Introduction

Here we report on the fifth iteration of the biennial listing of a consensus of 25 primate species considered to be amongst the most endangered worldwide and the most in need of urgent conservation measures. The first was drawn up in 2000 by the IUCN/SSC Primate Specialist Group, together with Conservation International (Mittermeier et al. 2000). The list was subsequently reviewed and updated in 2002 during an open meeting held during the 19^th Congress of the International Primatological Society (IPS) in Beijing, China (Mittermeier et al. 2002). That occasion provided for debate among primatologists working in the field who had first-hand knowledge of the causes of threats to primates, both in general and in particular with the species or communities they study. The meeting and the review of the list of the World's 25 Most Endangered Primates resulted in its official endorsement by the IPS, and became as such a combined endeavor of the Primate Specialist Group, the IPS, and Conservation International. A third revision was carried out at a meeting in August 2004, at the 20^th Congress of the IPS in Torino, Italy (Mittermeier et al. 2006). The fourth, covering the biennium 2006–2008, was the result of a meeting held during the 21^st Congress of the International Primatological Society (IPS), in Entebbe, Uganda, 26–30 June 2006 (Mittermeier et al. 2007).

The list of the world's 25 most endangered primates for the biennium 2008–2010 was drawn up at an open meeting held during the 22^nd Congress of the International Primatological Society, Edinburgh, UK, 3–8 August 2008. Our most sincere thanks to the organizers of the congress: Paul Honess (University of Oxford), Phyllis Lee (Stirling University), Hannah Buchanan-Smith (Stirling University), Ann Maclarnon (Roehampton University), and William Sellers (Manchester University).

As was the case for the 2004–2006 report, the texts for each species—reporting on their conservation status and threats—have counted on the extraordinary collaboration and expertise of those who know most about them; 85 contributors in all. We are most grateful for their time and dedication. Their contributions guarantee the authority of this report in describing the reasons why these primates are in such danger, and we hope it will be effective in drawing attention to the plight of each and in garnering support for the appropriate concern and action by those who can contribute to saving them.

The World's 25 Most Endangered Primates: 2008–2010

The 2008–2010 list of the world's 25 most endangered primates has five species from Madagascar, six from Africa, 11 from Asia, and three from the Neotropics—five lemurs, a galago and the recently described kipunji from Tanzania, two red colobus monkeys, the roloway monkey, a tarsier, a slow loris from Java, four langurs (the pig-tailed langur from Indonesia, two so-called karst species from Vietnam, and the purple-faced langur from Sri Lanka), the Tonkin snub-nosed langur and the gray-shanked douc, both from Vietnam, the cotton-top tamarin and the variegated spider monkey from Colombia (the latter also from Venezuela), the Peruvian yellow-tailed woolly monkey, two gibbons (one from China/Vietnam, the other from India, Bangladesh and Myanmar) and two of the great apes (the Sumatran orangutan and the Cross River gorilla from Nigeria and Cameroon).

The changes in the list compared to the previous one of 2006–2008 (see Tables 3 and 4) were not because the situation of the six species dropped has improved; unfortunately, far from it. Most of the changes were made so as to highlight other closely related species, which are also in dire straits regarding prospects for their future survival.

Lepilemur sahamalazensis was replaced by Lepilemur septentrionalis. Both are from the northernmost parts of Madagascar, both have minute populations in tiny, tiny geographic ranges, and both suffer from hunting pressure and habitat loss.

Table 1.

The World's 25 Most Endangered Primates 2008–2010.

Loris tardigradus nycticeboides from Sri Lanka (2004 and 2006) was replaced by the Javan slow loris, representing a crisis threatening all the Asian lorises. The massive and crushing trade in them for pets and for commerce in traditional medicines, compounded by widepread forest loss, is causing their rapid decline. The Javan slow loris, representing the plight of all, is evidently the hardest hit of any of the lorisiformes in this respect.

The 2008 IUCN Red List of Threatened Species recognizes 19 red colobus monkeys (Procolobus). Five were Not Evaluated (NE), two were ranked as Near Threatened (NT), seven were ranked as Endangered (EN), and three were ranked as Critically Endangered (CR). Only one of the red colobus monkeys, Proclobus rufomitratus oustaleti, from Central Africa, north of the River Congo, was ranked as of Least Concern (LC). These colobus monkeys are particularly susceptible to hunting—the widespread and insidious bushmeat trade—and also suffer from forest loss and fragmentation. Four red colobus monkeys have been listed over the five iterations of this list since 2000: Procolobus badius waldroni, Procolobus p. pennantii and Procolobus epieni, from the widely destroyed, fragmented and hunted forests of West Africa, and Procolobus r. rufomitratus from the few small gallery forest patches remaining along the Tana River in Kenya. The Tana River red colobus has been on the list since 2002. The Niger Delta red colobus, first discovered only in 1993, was placed on the list in this biennium 2008–2010 because its range is very small, it suffers from bushmeat hunting, and there is widespread degradation of the Niger Delta's forests; there is every reason to suspect that its numbers are declining.

Table 2.

The world's 25 most endangered primates 2008–2010 are spread through 17 countries. Those which stand out are Madagascar (five species), Vietnam (five species), and Indonesia (four species).

Table 3.

The following primates included on the 2006–2008 list were removed from the 2008–2010 list.

Table 4.

The following six primates were placed on the list for the first time.

The Hainan gibbon, Nomascus hainanus, was taken off the list, despite the fact the world population of this species numbers less than 20 individuals. Considerable efforts are now underway to protect this species. The closely related eastern black crested gibbon, however, is also extremely threatened. It occurs in a very small region on the Vietnam/China border and numbers are estimated at around 100 in just 18 groups. The remaining few forest patches where it still survives are being destroyed (charcoal, firewood, and clearance for agriculture and pasture).

Of the two remaining species on the list for the first time, one was at the expense of one of the three red colobus monkeys, and the other at the expense of the Ecuadorean spider monkey, Ateles fusciceps, both on the 2006–2008 list. The loss of A. fusciceps of the Choco region of Ecuador was due to the lack of a spokesperson on its behalf. The addition of the cotton-top tamarin, Saguinus oedipus, endemic to northern Colombia, was due to a recent distribution-wide survey of the species that had revealed a highly fragmented and severely diminished population, with even the few small protected areas where it occurs suffering extensive forest loss. Sclater's lemur, Eulemur flavifrons, is one of the least-studied of all Eulemur species. The single population that occurs on the Sahamalaza Peninsula of Madagascar is undergoing a very rapid decline because of hunting and trapping and the destruction of its forests due to slash-and-burn agriculture and selective logging.

New Species

Five of the world's 25 most endangered primates are species only recently described: the Rondo dwarf galago (Galagoides rondoensis) by Paul Honess in Kingdon (1997); the gray-shanked douc (Pygathrix cinerea) by Tilo Nadler in 1997; the Niger Delta red colobus (Procolobus epieni) by Peter Grubb and C. Bruce Powell in 1999; the kipunji (Rungwecebus kipunji) by Carolyn Ehardt and colleagues in Jones et al. (2005); and the Siau Island tarsier (Tarsius tumpara) that was first described by Myron Shekelle and colleagues in 2008. Eighty-six primates—species and subspecies—have been described since 1990; 47 from Madagascar, 10 from Africa, 11 from Asia, and 17 from the Neotropics (statistic current 25 July 2009). Fifty-four of the primates described since 1990 are prosimians, and 32 are monkeys. Many of these new primates have very restricted distributions (one of the reasons they were not discovered sooner) and some are known only from their type localities. With more information becoming available it is possible to predict that many will be future candidates for this list.

Threats

The 2008 IUCN Red List of Threatened Species assessed the status of 634 primate taxa. Of these, 303 (47.8%) were ranked as threatened (Vulnerable, Endangered or Critically Endangered); 37% of the African primates, 43% of the lemurs, 71% of the Asian primates, and 40% of the Neotropical primates.

Nearly half of all the world's primates are threatened; principally due to habitat loss and hunting. In the face of habitat degradation and loss, factors which determine more precisely the status of each primate taxon include the following: the size of the geographic range of the taxon (extent of occurrence), the area actually occupied by the taxon (area of occupancy), the pattern of habitat loss (fragmentation, including fragment size and degree of fragment isolation), the extent and form of habitat degradation (for example, intensive logging, light selective logging, agroforestry, firewood collection, exploitation of non-timber products, understorey damage by cattle, and edge effects depending on fragment size), and the intrinsic resilience of the taxon to fragmentation and degradation. Hunting, of course, can vary in intensity (occasional, subsistence, for local, regional or international commerce [bushmeat]) and purpose (for food, traditional medicine, talismans and potions, for bait, pets or for biomedical research). Susceptibility to hunting pressure will depend on demographic (life history) variables, on overall population size and the geographic patterns of populations (some protected by remoteness, the degree to which populations are connected [sources and sinks]), and the ease with which they can be hunted (group size and habits, and accessibility, for example).

The depredations of hunting and habitat destruction on the populations of each primate taxon are behind the two principal parameters that result in them being placed on this list of the world's 25 most endangered primates—very, very small population sizes and very rapid declines in numbers. Of the 206 primates on the 2008 IUCN Red List that are classified as Critically Endangered or Endangered, fifty-four (26%) have at some time been placed on the world's 25 most endangered list. Seven of them have been on all five of the lists since 2000: the silky sifaka (Propithecus candidus), four Asian colobines—Delacour's langur (Trachypithecus delacouri), the Cat Ba langur (T. p. poliocephalus), the gray-shanked douc (Pygathrix cinerea), and the Tonkin snub-nosed monkey (Rhinopithecus avunculus)—the Cross River gorilla (Gorilla gorilla diehli), and the Sumatran orangutan (Pongo abelii) (Table 6).

Table 5 provides a summary of the threats to each of the world's 25 most endangered primates 2008–2010 as identified in the species profiles in this report.

Table 5.

Threats to the world's 25 most endangered primates 2008–2010 as given in the species' profiles in this report.

Table 6.

The following table shows the five lists produced to date. The seven species shaded are those which have remained on the list since 2000.

The World's 25 Most Endangered Primates 2008–2010 Profiles

Gray-headed Lemur

Eulemur cinereiceps (Milne-Edwards and Grandider, 1880)

Madagascar

(2004, 2006, 2008)

The gray-headed lemur (Eulemur cinereiceps) has a complicated taxonomic history. It is closely allied with the brown lemurs (Eulemur spp.), particularly the neighboring collared lemur (E. collaris). This taxon was until recently classed as a subspecies of Eulemur fulvus (Tattersall 1982; Mittermeier et al. 1994; Pastorini et al. 2000). However, cytogenetic and molecular genetic analyses, as well as infertility in crosses with collared lemurs, suggest full species status (Djletati et al. 1997; Wyner et al. 1999). The name derives from plates in Milne-Edwards and Grandidier (1890) and was applied to museum specimens from the southeastern coast near Farafangana by Schwarz (1931). Groves (1974) also used this name for “white-cheeked” specimens from southeastern Madagascar, distinguishing them from E. collaris. Subsequently, Rumpler (1975) made a similar distinction based on karyotypes, but adopted the presumably junior synonym E. albocollaris (or “white-collared lemur”). The latter nomenclature was supported by Tattersall (1979, 1982) and others, and came to prevail in the literature. It was later suggested that E. cinereiceps and E. albocollaris might represent separate taxa (Groves 2001; Mittermeier et al. 2006); in this scenario, E. cinereiceps would likely be found in coastal forests—the localities for specimens discussed by Schwarz (1931)—whereas E. albocollaris would be restricted to interior forests (for example, near Vondrozo). This idea was tested with available evidence from genetic sampling and population surveys (Johnson et al. 2008). Although not all original localities for E. cinereiceps could be sampled due to extensive fragmentation and lemur extirpations in this region during the last century, there is no evidence to date from mtDNA or phenotypes for a coastalinterior division. For now it seems most likely that the region contains just one species and that the name E. cinereiceps has priority (Johnson et al. 2008). Further ground surveys and genetic sampling should be conducted to confirm these findings.

The gray-headed lemur has one of the most restricted distributions of any Eulemur species. It occurs only in south-eastern Madagascar from just north of the Manampatrana River to near the Mananara River in the south (Petter and Petter-Rousseaux 1979; Tattersall 1982; Irwin et al. 2005). This range includes a continuous forest corridor in the interior escarpment and small forest relicts in the coastal plain. In the north, there is a hybrid zone with E. rufifrons centered in Andringitra National Park, extending south to the vicinity of Karianga and north beyond Ankarimbelo (Sterling and Ramarason 1996; Wyner et al. 2002; Irwin et al. 2005). This encompasses an area of up to 50% of the range of “pure” E. cinereiceps. The southern boundary of the species is not well established, and could extend to Vohipaho Forest near Vangaindrano (where E. cinereiceps may be sympatric with E. collaris; H. Andriamaharoa unpubl. data). Other than Andringitra National Park, E. cinereiceps is only found in two protected areas: Manombo Special Reserve and the recently established conservation project at Mahabo Forest, both near Farafangana. The large Andringitra population consists almost entirely of hybrids (Wyner et al. 2002), whereas degraded coastal forests at Manombo and Mahabo contain only c.750 E. cinereiceps individuals (C. Ingraldi in prep.). Population densities across the range tend to be low relative to other Eulemur species (Johnson and Overdorff 1999; Johnson and Wyner 2000). Recent analyses combining ground surveys and Landsat imagery indicate that the total habitat remaining within the gray-headed lemur range is approximately 700 km², with an estimated remaining population of 7,265 ± 2,268 individuals (Irwin et al. 2005).

Information regarding the natural history of the gray-headed lemur derives largely from recent studies conducted at the interior Vevembe Forest, along with new long-term studies currently underway at Manombo and Mahabo. This species has a highly frugivorous diet, supplemented with flowers, leaves, and fungi. Pandanus spp. flowers are an especially important food late in the dry season at Vevembe (Johnson 2002). Pandanus fruit also comprises a major component of the diet at Mahabo, along with Noronhia, Pyrostria, and Uapaca (H. Andriamaharoa, C. Birkinshaw, A. Rued unpubl. data). At Manombo, E. cinereiceps has been observed eating non-native plants like Aframomum angustifolium and a shelf fungus that grows on invasive Cecropia (Ralainasolo et al. 2008). Feeding on such items may enable E. cinereiceps to cope with habitat disturbance, and perhaps in part to avoid competition with other lemurs such as Varecia for native plants. The species is cathemeral (active both day and night) throughout the year. It is an adept arboreal quadruped with frequent use of leaping behaviors, and its limb kinematics corresponds closely with those of Eulemur collaris (Stevens et al. in review). Social groups tend to be multi-male/multi-female and regularly exhibit fission-fusion (Overdorff and Johnson 2003; Johnson 2006). Group size may reach as many as 16 individuals (Johnson 2002). Coastal populations have smaller social groups, with apparently frequent dispersal of individuals among groups (H. Andriamaharoa, S. Martin, C. Ingraldi, A. Rued unpubl. data). Like other lemurs, reproduction is highly seasonal, although extra-seasonal copulations (with at least one birth) have been recorded at Mahabo (A. Rued in prep.).

Deforestation and hunting present the greatest threats to the survival of the gray-headed lemur. Populations in the Manombo lowland rain forest and Mahabo littoral forest are particularly vulnerable to these pressures due to the fragmentation and isolation of the coastal landscape, as well as possible small population effects. They are also susceptible to powerful stochastic climatic events: a cyclone that struck this region in 1997 reduced lemur populations by approximately 50% (Ratsimbazafy et al. 2002). These coastal populations have apparently undergone a significant genetic bottleneck, and effective population size (number of breeding individuals) falls well below total population estimates (R. Brenneman, E. E. Louis Jr., S. Johnson in prep.). The extensive hybrid zone with E. f. rufus may also pose a risk to the gray-headed lemur; research is presently being conducted to assess the direction and magnitude of gene flow across the contact zone and “pure” populations (K. Delmore in prep.). Current research is also underway to investigate disease ecology in E. cinereiceps. Preliminary evidence suggests heavy infestations of some parasites (for example, pinworms) that could reduce fitness, particularly if degraded environmental conditions compromise immune response (S. Martin in prep.).

The Malagasy government, conservation NGOs, and researchers are together taking steps to counter these alarming trends. The Durrell Wildlife Conservation Trust is working in partnership with Madagascar National Parks to strengthen protection at Manombo, including possible expansion of the Special Reserve. Conservation education and tree-planting programs have also been established in the Manombo communities. Missouri Botanical Garden has supported community-based initiatives to preserve Mahabo Forest within the new framework for protected areas in Madagascar; similar programs are underway at Vohipaho, which may also maintain a small E. cinereiceps population. Conservation International is presently initiating programs for the management of the Fandriana-Vondrozo forest corridor. This will be critical for the long-term survival of the gray-headed lemur, as the vast majority of populations are found within this corridor and few are presently protected. Researchers from Université d'Antananarivo, University of Calgary, Stony Brook University, Henry Doorly Zoo, Ohio University, and other institutions are active in studying gray-headed lemur ecology, social systems, population dynamics, and genetics to better understand the risks and baseline requirements for this still poorly known species.

Steig Johnson, Jonah Ratsimbazafy, Nancy Stevens, Hubert Andriamaharoa, Sara Martin & Fidimalala Ralainasolo

Sclater's Black Lemur, Blue-Eyed Black Lemur

Eulemur flavifrons (Gray, 1867)

Madagascar

(2008)

The blue-eyed black lemur or Sclater's black lemur was rediscovered by science only in 1983 after more than a century of uncertainty about its existence (Koenders et al. 1985; Meier et al. 1996). Its taxonomic validity was thereafter confirmed independently by Rabarivola (1998) and Pastorini (2000). The species was until recently regarded as a subspecies of Eulemur macaco, but was elevated to full species status on the basis of the consistency of the morphological differences between the black lemur and the blue-eyed black lemur and the pairwise genetic distances between macaco and flavifrons of 68–72 bp (which are in the same range as between the former E. fulvus subspecies, i.e., 29–90 bp, according to Pastorini 2000). Furthermore, the fact that the hybrid zone between the two taxa is restricted to just the north-eastern part of the distribution of E. flavifrons (Andrianjakarivelo 2004; Schwitzer et al. 2005, 2006; Mittermeier et al. 2008) is in favour of this new taxonomy.

Eulemur flavifrons is still one of the least-studied of all Eulemur species. The species occurs only in northwest Madagascar in a very small area of about 2,700 km², south of the Andranomalaza, north of the Maevarano, and west of the Sandrakota rivers, where it inhabits primary and secondary forest fragments (Koenders et al. 1985; Meyers et al. 1989; Rabarivola et al. 1991; Mittermeier et al. 1994). The area of repartition of Eulemur flavifrons lies within a transition zone between the humid Sambirano region in the north and the western dry deciduous forest region in the south, harboring semi-humid forests with tree heights of up to 30 m on ferruginous alkalescent and alkaline soils based on sandstone, basalt or clay (IRNT 1991a). Average annual precipitation is around 1,600 mm (IRNT 1991b).

There is only a small population of Eulemur flavifrons remaining, the largest part of it living in forest fragments on and adjacent to the Sahamalaza peninsula (Mouton 1999). Rakotondratsima (1999) estimates the population of the Sahamalaza peninsula to be about 450–2,300 individuals and to have declined about 35.3% in three years (see also Andriamanandratra 1996). Andrianjakarivelo (2004) found the mean density of E. flavifrons in eight inventoried forest fragments to be 24 individuals per km² (range: 4–85 ind./km²). A total count in two different fragments of the Ankarafa forest on the Sahamalaza Peninsula yielded a density of 60 individuals per km² (Schwitzer et al. 2005, 2007a). However, the density of the species in Ankarafa seems to be higher than in any other forest in the range of E. flavifrons (Randriatahina and Rabarivola 2004). Extrapolating the two density estimates of Andrianjakarivelo (2004) and Schwitzer et al. (2005) to the total surface of the terrestrial core zones of the recently created Sahamalaza — Iles Radama National Park (115.8 km²) yields a remaining, severely fragmented population of 2780–6950 blue-eyed black lemurs. Eulemr flavifrons was assessed as Critically Endangered (CR A2cd) by the International Union for Conservation of Nature (IUCN) at their most recent Red List Assessment in April 2005, based on an 80% population reduction during the last 25 years. The principal threats to its survival are forest destruction due to slash-and-burn agriculture and selective logging, continued hunting and trapping, especially by the Tsimihety in the eastern part of its distribution, and live capture for the local pet trade (Gerson 1995; Rakotondratsima 1999). Andrianjakarivelo (2004) found a density of up to 570 traps/km² in certain areas where E. flavifrons occurs.

The blue-eyed black lemur's home range size and use differs between primary and secondary forest fragments, indicating that it is somewhat able to adapt to different types of habitat. Larger home ranges and lower densities of E. flavifrons in secondary forest as compared to primary forest, however, suggest that the former is less suitable habitat for the species (Schwitzer et al. 2007a). During a 12-month study, E. flavifrons consumed parts of 72 different plant species from 35 families; 52.3% of these were fruits and 47.7% were leaves. The animals also fed on flowers, insects, insect exudates and fungi (Polowinsky and Schwitzer in press). Eulemur flavifrons exhibits a bimodal activity pattern, which peaks during the morning and evening twilight. It shows activity bouts during the day and night year-round. Nocturnal illumination and the proportion of illuminated lunar disc are positively associated with the amount of nocturnal activity. Total daily activity, as well as nocturnal activity, is higher in secondary forest than in primary forest (Schwitzer et al. 2007b).

Blue-eyed black lemur groups are multi-male multi-female, ranging in size from 6 to 10 individuals, including 4 to 7 adults (G. H. Randriatahina and J. J. Roeder in prep.). Both sexes disperse, but only males have been seen moving into a foreign social group. The sex ratio at birth varies strongly between years and could be male-biased (G. H. Randriatahina and J. J. Roeder in prep.). Births occur between late August and October, at the end of the dry season. During two successive birth seasons, infant mortality was 22.7%. Infants start to become independent at around eleven weeks of age (S. Volampeno in prep.).

Parts of the Sclater's black lemur's range officially received protected area status in June 2007 (Parc National Sahamalaza — Iles Radama), including the Sahamalaza Peninsula and some mainland forests to the north and east (Moisson et al. 1999; Lernould 2002; Schwitzer and Lork 2004; Schwitzer et al. 2006). The Sahamalaza Peninsula is also a UNESCO Biosphere Reserve. The Association Européenne pour l'Etude et la Conservation des Lémuriens (AEECL) is a consortium of European zoos that have joined forces to conserve Madagascar's lemurs, with the involvement of representatives of local communities from the Sahamalaza Peninsula and representatives of WCS and several other environmental institutions. AEECL implemented a natural resource management programme in Sahamalaza in December 2000 in order to protect the remaining lemur habitat and to improve the living standards of the local human population. AEECL also maintains a field station in Sahamalaza, which serves as a basis for studying the conservation ecology of E. flavifrons and of other lemur species in the area.

As of 2008, there were 30 blue-eyed black lemurs living in European zoos (Moisson and Prieur 2008). The European captive population of the subspecies is being managed in a European Endangered Species Programme (EEP) coordinated by Mulhouse Zoo.

Christoph Schwitzer, Pierre Moisson, Guy H. Randriatahina, Sylviane Volampeno, Nora Schwitzer & Clément J. Rabarivola

Northern Sportive Lemur

Lepilemur septentrionalis Rumpler and Albignac, 1975

Madagascar

(2008)

The northern sportive lemur (Lepilemur septentrionalis) was originally described based on cytogenetic and morphometric characteristics (Rumpler and Albignac 1975, see also Rumpler et al. 2001). Its taxonomic status has been supported by more detailed cytogenetic, morphogenetic and especially molecular data (Rumpler et al. 2001; Ravaorimanana et al. 2004; Andriaholinirina et al. 2006), and accepted in recent taxonomic revisions of primates (Groves 2001, 2005) and lemurs (Mittermeier et al. 2006, 2008). It is believed to be strictly limited to a few small patches of dry forest in the far north of Madagascar, just to the south of Antsiranana on the east coast. Mittermeier et al. (2006) list the following localities: very small remnant forest patches near the villages of Madirobe and Ankarongana in the Sahafary region, and in the immediate vicinity of Andrahona, a small mountain about 30 km south of Antsiranana, east of Route Nationale 6 (observations by Yves Rumpler, Russell A. Mittermeier).

It is nocturnal, spending the day sleeping in tree holes, and very little is known about its ecology and behavior. Total numbers are unknown but, taking into account the limited distribution of L. septentrionalis in the forests of Sahafary, Andrahona and Andranomadiro, there are probably only about 100–150 individuals remaining. Tree-felling for charcoal continues at an alarming rate and the animals suffer from hunting. Surveys of five areas in 2007 provided the following population estimates: 1) Area of Andrahona (forest patches and gallery forests of Andrahona, Analajanana, and Analanjavavy)—20 individuals in the entire area; 2) Area of Ankarakataova (forests of Ankarakataova Be and Ankarakataova kely)—none found; and 3) Area of Sahafary (degraded forest patches in Western Sahafary, Sahafary East, Sahafary North, Andravina, Sahandrano, Andranomadiro, and Analalava)—about 100 individuals. None of these areas is protected.

The combination of a very small range containing little and rapidly decreasing suitable habitat with high pressure from hunting makes this species especially threatened. A consortium of the Association Européenne pour l'Etude et la Conservation des Lémuriens (AEECL), the University Louis Pasteur of Strasbourg and the Fondation Nature et Decouverte supported the field work and the genetic study. Socioeconomic studies are under way to determine the anthropogenic effect on the remaining population (Lernould 2006).

Iary Ravaorimanana, Alphonse Zaramody, Clément Rabarivola & Yves Rumpler

Silky Sifaka

Propithecus candidus Grandidier, 1871

Madagascar

(2000, 2002, 2004, 2006, 2008)

Propithecus candidus is a large white sifaka from northeastern Madagascar. Silky sifakas have recently been raised to full species (Mayor et al. 2002, 2004; Mittermeier et al. 2006), though some still consider this taxon to be a subspecies of Propithecus diadema (see Groves 2001; reviewed in Tattersall 2007). It has a head-body length of 48–54 cm, a tail length of 45–51 cm, a total length of 93–105 cm, and a weight of 5–6.5 kg (Lehman et al. 2005). The pelage is long, silky and white, which gives this species its common English name. In some individuals, silver-gray or black tints may appear on the crown, back and limbs, and the pygal region (at the base of the tail) is sometimes yellow. The muzzle and face are bare, the skin a mix of pink and black, with some individuals having all pink or all black faces. The tips of the naked black ears protrude just beyond the white fur of the head and cheeks. This species does not occur with any other sifakas and cannot be confused with any lemurs within its range.

Unlike Propithecus perrieri and P. edwardsi, where adult males and females are difficult to distinguish, adult male and female P. candidus can be readily distinguished from one another by the pelage coloration of the upper chest. Adult males possess a large brown “chest patch” that results from chest scent marking with the sternal gular gland. As rates of male chest scent marking increase during the mating season, male chest patches become larger and can cover the entire front torso to the abdomen (Patel 2006a).

The most recent IUCN Red List assessment (2008) lists P. candidus as Critically Endangered. This is one of the rarest and most critically endangered lemurs. Global population size is estimated between 100 and 1,000. Silky sifakas are hunted throughout their range as there is no local taboo, or fady, against eating them. Habitat disturbance, such as slash-and-burn agriculture (tavy), logging of precious woods (for example, rosewood) and fuel wood, also occurs in and adjacent to the protected areas where they are found (Patel et al. 2005b; Patel 2007b; Nielson and Patel 2008).

The silky sifaka has a very restricted range in northeastern Madagascar that includes the humid forest belt extending from Maroantsetra to the Andapa Basin and the Marojejy Massif. Marojejy National Park marks the northern limit of its current distribution, although at one time it occurred as far north as Bemarivo River near Sambava. The Androranga River may represent the northwestern range limit within the Tsaratanana Corridor. The Antainambalana River, within the Makira Conservation Site, is believed to be the southern limit. Silky sifakas may occur in northeastern Makira (Amparihibe, Bezavona), although they have not yet been observed there (Milne-Edwards and Grandidier 1875; Tattersall 1982; Wilme and Callmander 2006; Patel and Rasolofoson et al. 2007; Andrianandrasana 2008). Recent unconfirmed reports have identified several groups of silky sifakas just outside of north-eastern Makira in the unprotected Maherivaratra forest (Mosesy, Marojejy National Park Guide Association Chief pers. comm., February 2009) which would represent a slight enlargement of their known geographic range. In Maherivaratra and Andaparaty, silky sifakas may actually be sympatric with Varecia, which had never been suggested before 2008.

Surveys have documented the presence of silky sifakas in Marojejy National Park (Humbert 1955; Guillaumet et al. 1975; Benson et al. 1976, 1977; Duckworth et al. 1988; Nicol and Langrand 1989; Sterling and McFadden 2000; Goodman et al. 2003), Anjanaharibe-Sud Special Reserve (Nicol and Langrand 1989; Schmid and Smolker 1998; Goodman et al. 2003), the Makira Conservation Site (Rasolofoson et al. 2007; Ratelolahy and Raivoarisoa 2007; Patel and Andrianandrasana 2008), the Betaolana Corridor (Goodman et al. 2003), and the Tsaratanana Corridor (WWF Andapa Projet Simpona pers. comm.).

The majority of the remaining population of P. candidus is found in just two protected areas managed by Madagascar National Parks (Andapa): Marojejy National Park and Anjanaharibe-Sud Special Reserve. A few groups have recently been found in the Makira Forest Protected Area (managed by the Wildlife Conservation Society) at two sites: Andaparaty (central-east Makira) and Manandriana, 44 km to the north-west, adjacent to the Anjanaharibe-Sud Special Reserve). Silky sifakas are also found in the Betaolana Corridorthat connects Anjanaharibe-Sud and Marojejy, as well as the unprotected Tsaratanana Corridor to the northwest. Further surveys are needed in Makira and in the western part of Anjanaharibe-Sud, which has recently been extended. Approximately 16 groups were found during a recent survey in western Marojejy near Antsahaberoaka (December 2008, pers. obs.).

A 14-month study (Patel 2006a; Patel et al. 2006) and two short studies (Kelley and Mayor 2002; Queslin and Patel 2008) have examined the behavioral biology, communication, and feeding ecology of silky sifakas in Marojejy National Park. Silky sifakas show the greatest elevational range of any of the sifakas; as low as 300 m in the Makira (Andaparaty) and as high as 1,875 m in Marojejy. Thus, they inhabit several types of elevation-specific habitats including primary montane rainforest, sclerophyllous forest, and even low ericoid bush at their highest elevations. Their social structure is variable; they can be found in male-female pairs, one-male groups, and multi-male/multi-female groups. Groups range in size from two to nine. Home ranges (95% Kernel) vary by site from 34 to 47 ha (Patel 2006b; Patel and Andrianandrasana 2008).

Approximately 25% of the day is spent feeding, 44% resting, and the remainder is devoted to social behavior (16.8%), traveling, and sleeping. Long bouts of terrestrial play involving adults are not uncommon. Rates of aggression are low, and occur mainly during feeding. Females have feeding priority over males. As in other eastern sifakas, P. candidus is a folivorous seed predator eating fruits, seeds and leaves from a very large number of plant species. A recent two-month study documented feeding from 76 species across 42 families (mainly trees, but many lianas as well). During this short study, the most important plant families in their diet were Moraceae (20.3%), Fabaceae (12.9%), Myrtaceae (12.6%), Clusiaceae (10.1%) and Apocynaceae (9.5%). The four most preferred foods accounted for 37.1% of total feeding time: fruit from Pachytrophe dimepate (16.1%), seeds from Senna sp. (8.4%), young leaves from Plectaneia thouarsii (6.5%), and fruit from Eugenia sp. (6.0%). Fifty-two percent of feeding time was spent eating leaves, 34% fruit, and 11% seeds. Flowers and soil were eaten rarely (Patel 2006b; Queslin and Patel 2008).

Mating is believed to occur on a single day each year in December or January. Infants are born in June or July. Females generally give birth to a single offspring every two years, although they have been seen to give birth in consecutive years (Patel 2006b). Infants initially grasp the fur on their mother's belly, and only about four weeks later begin to ride “jockey style” on their mother's back. As is typical of Propithecus, all group members interact affiliatively with infants. Grooming is the most frequent form of non-maternal infant care, followed by playing, occasional carrying, as well as nursing in a few remarkable instances (Patel et al. 2003a; Patel 2007a). Dispersal has been observed only once, when a young adult male immigrated in 2007, aggressively forcing the older resident male out of the group he had been a member of for at least seven years. Although eastern sifakas generally exhibit male and female group transfer, female transfer in P. candidus has yet to be observed.

Other than humans, only the fossa (Cryptoprocta ferox) has been documented as a predator of the silky sifaka (Patel 2005). No aerial predation attempts by raptors have ever been observed, although these sifakas sometimes stare skyward and emit loud “aerial disturbance” roars in the presence of the large Madagascar buzzard (Buteo brachypterus), which does not, however, eat lemurs, only small birds. Loud sneeze-like “zzuss!” vocalizations are their second type of alarm call, and are emitted in response to terrestrial disturbances and to lost calls by other group members, as well as after receiving aggression. Acoustic analyses have revealed sex and individual differences in the acoustic structure of the silky sifaka “zzuss” vocalization (Patel et al. 2003b; Patel et al. 2006).

As in all prosimians, olfactory communication is well developed. Eastern sifakas have several specialized scentmarking glands that include a sebaceous chest gland only found in males, and mixed apocrine-sebaceous genital glands in both sexes (Schilling 1979). Sifakas do not allomark, as in Eulemur, by directly scent-marking conspecifics. Females scent-mark trees by rubbing their genital glands in a rhythmic vertical motion. Males scent-mark trees in a number of ways, by rubbing them with their chest gland, genital glands, or a combination of the two. Males routinely gouge trees with their toothcombs just prior to chest-marking, which leaves long-lasting visible marks. Silky sifakas do not eat bark or gum, so such non-nutritive male tree-gouging is likely communicative in function (Patel and Girard-Buttoz 2008). Both sexes often urinate while scent-marking. Although males scent-mark two or three times as often as females, female scent-marks are responded to far more often and more quickly than male marks. A one-year study found that only 17% of male P. candidus marks are responded to by other group members, but 71% of female marks received a response, on average within 61 seconds (Patel 2006a). In both P. edwardsi and P. candidus, male overmarking of a female's mark is the most common response, followed by males overmarking the scent-marks of other males. Male eastern sifakas preferentially use one type of scent-marking, combined chest-anogenital marking, when depositing an overmark (Andrianandrasana et al. 2007). The high rates of overmarking practiced by male eastern sifakas lead to totem-tree marking, in which certain trees are covered with male scent-marks and gouge marks. Extensive scent-marking of the home range border has not been observed in P. candidus (Patel 2006a; Ritchie and Patel 2006; Patel and Girard-Buttoz 2008).

Erik R. Patel

Africa

Roloway Guenon

Cercopithecus diana roloway (Schreber, 1774)

Ghana and Côte d'Ivoire

(2002, 2006)

There are two subspecies of Cercopithecus diana, both highly attractive, arboreal monkeys that inhabit the Upper Guinean forests of West Africa (Grubb et al. 2003). The roloway subspecies is distinguished by its broad white brow line, long white beard and yellow thighs. Groves (2001) considers the two subspecies to be sufficiently distinct to be regarded as full species. Of the two forms, the roloway, which is known from Ghana and eastern Côte d'Ivoire, is more seriously threatened with extinction. In fact, along with the white-naped mangabey (Cercocebus atys lunulatus) and Miss Waldron's red colobus (Procolobus badius waldroni), it is among the three most endangered monkeys of the Upper Guinea forest block and a target species of the relentless bushmeat trade (Oates 1996).

As primatologists have searched the forests of Ghana and Côte d'Ivoire for evidence of living red colobus, they have also documented the continued decline of both the roloway guenon and white-naped mangabey, which seem to be found in (or absent from) many of the same forests (Struhsaker and Oates 1995; Oates et al. 1996/1997; McGraw 1998a; Koné 2004; Oates 2006). In Ghana, roloway guenons have been steadily extirpated from both unprotected and protected areas (for example, Bia National Park) and the monkey is nearing extinction in that country, if it has not disappeared already. Several recent surveys have failed to find roloways in any reserves in western Ghana. It is possible that the Ankasa Conservation Area still contains a few roloway individuals (Magnuson 2003), but in 2006 a wildlife guard reported to J. F. Oates (unpubl.) that he had not seen the monkey for several years. Careful surveys of Ankasa and Bia Conservation Areas and Cape Three Points Forest Reserve in 2007–2008 by West African Primate Conservation Action did not locate any roloways, but unconfirmed reports of their continued survival at Ankasa were received (S. Gatti pers. comm.). A thorough survey of the Dadieso Forest Reserve (where the monkey was also reported in the recent past) should be a high priority.

In neighboring Côte d'Ivoire, the Roloway guenon is not known from any protected areas and the monkey's status is equally dire. Surveys made ten years ago documented roloways in two forests, the Yaya Forest Reserve and the Tanoé forest adjacent to the Ehy Lagoon (McGraw 1998b, 2005; Koné and Akpatou 2005). Hunters had also reported small numbers of roloways in the Parc National des Iles Ehotilé (Koné and Akpatou 2005). Subsequent surveys of eighteen areas made between 2004 and 2006 confirmed the presence of roloways only in the Tanoé forest (Gonedelé Bi et al. 2008). This evidence suggests that the roloway monkey may have been eliminated from at least two forest areas (Parc National des Iles Ehotilé, Yaya Forest Reserve) within the last decade and that the guenon's distribution in Côte d'Ivoire is now restricted to the Tanoé forest (Koné and Akpatou 2005). In 2007, local informants reported the presence of roloways in the Dassioko, Niouniourou, Port Gautier, Mabi and Yaya forest reserves, however surveys of these areas yielded no direct evidence of their presence (G. Campbell pers. comm.). If roloways have been eliminated from Ghana's Ankasa Conservation Area, then the Tanoé forest could be a final refuge for this guenon. This wet forest also harbors one of the few remaining populations of white-naped mangabeys in Côte d'Ivoire and, perhaps, a small number of Miss Waldron's red colobus. The Tanoé forest is under direct threat from a large palm oil company (PALMCI) and several organizations (CEPA, WAPCA) are lobbying against the company and have sponsored local awareness campaigns (Koné 2008). As the potential last refuge for roloways, white-naped mangabeys, and Miss Waldron's red colobus, the protection of the Tanoé forest should be the highest conservation priority.

W. Scott McGraw and John F. Oates

Tana River Red Colobus

Procolobus rufomitratus (Peters, 1879)

Kenya

(2002, 2004, 2006, 2008)

Gallery forests found in the lower Tana River, Kenya, appear to be remnants of a previously continuous forest that extended from Central Africa to East Africa 25,000–30,000 years ago). The forests are part of the East African Coastal Forests Biodiversity' Hotspot and for this, and other reasons, are of great conservation value. In particular, they are the only habitat for two endemic primate species; Tana River red colobus, Procolobus rufomitratus (Peters, 1879), and Tana River mangabey, Cercocebus galeritus Peters, 1879. These two species inhabit the forests along a 60-km stretch of the lower Tana River from Nkanjonja to Mitapani (01°55′S, 40°05′E). All of these forests are small, ranging in size from <1 ha to c. 500 ha. Six other species of nonhuman primates are found in this area. However, the Tana River red colobus and Tana River mangabey are forest dependent, and account for the bulk of the primate biomass in these forests.

The Tana River red colobus and the Tana River mangabey are both greatly threatened by forest loss and fragmentation caused by a growing human population. Forest is cleared mainly for agriculture; an estimated 50% of the original forest has been lost in the last 20 years. In addition, people use the remaining forest for materials to build homes and canoes, and for other non-timber forest products. Consequently, the current population of the Tana River red colobus is less than 1,000 individuals and declining, while the population of the Tana River mangabey is not much larger and declining. Furthermore, it has recently been found that the forest loss and fragmentation causes high levels of parasitism in these two primates (Mbora and McPeek 2009). The effect of this on the status of these two populations is currently unknown.

The long-term survival of the two endemic Tana River primates looks very bleak. In January 2007, the High Court of Kenya ruled that the Tana River Primate National Reserve (TRPNR), where 13 km² of forest were protected, was not established in accordance with the law. The TRPNR must, therefore, be degazzetted, which means that none of the habitat of the Tana River red colobus and Tana River mangabey is legally protected. Furthermore, habitat loss outside the TRPNR has been exacerbated by the failure of the Tana Delta Irrigation Project's (TDIP) rice-growing scheme (under the administration of the Tana and Athi Rivers Development Authority' [TARDA], with financing from Japan International Cooperation Agency [JICA]) to protect forest patches on their land. Now TARDA is in the process of expanding its activities in the region by establishing a 110 km² sugar cane plantation. In addition, a further 500 km² of land in and around the delta are earmarked for the development of sugarcane plantations by Mat International Sugar Limited. These new plantations will result in a large influx of people and an increase in the demand for forest resources.

Curiously, despite the dire circumstance of Tana River red colobus and the species being on the list of The World's 25 Most Endangered Primates since 2002, not one conservation agency is working in the forests of the lower Tana River. A five-year Kenya Wildlife Service (KWS) and Kenya Forest Department project, funded by the World Bank/GEF, was initiated in 1996 to enhance conservation and protection of the primates and forests. Unfortunately, this potentially important project was terminated prematurely due to poor project management. This left the responsibility for the conservation and protection of the Tana River's forests and primates entirely to the KWS.

Despite the troubles highlighted above, the Tana River situation is not hopeless. One of us (DNMM) has maintained a (relatively poorly funded) research project in the area over the last five years. He has thus been able to monitor developments on the ground. In addition, more than 250 families who farmed within the TRPNR were voluntarily relocated in 2005 to Kipini (about 90 km away) by the KWS. At the moment, there appears to be growing concern for forest and biodiversity' conservation among local people. For example, several local leaders have expressed a desire to convert the now degazetted TRPNR into a community wildlife sanctuary. However, there is need for strong support and encouragement from conservation organizations for a community-based conservation effort.

David N. M. Mbora & Thomas M. Butynski

Niger Delta Red Colobus Monkey

Procolobus epieni Grubb and Powell, 1999

Niger Delta, Nigeria

(2008)

This colobus monkey is listed as Critically Endangered on the 2008 IUCN Red List of Threatened Species. It only became known to science in 1993 in the course of a biodiversity' survey co-ordinated by C. Bruce Powell (Powell 1994). The monkey's scientific name is based on its name in the Ijaw language of the people who inhabit the limited area (1,500 km²) where it occurs in the central Niger Delta. Studies of vocalizations and mitochondrial DNA suggest that epieni is not closely related to its closest geographic relatives, the Bioko red colobus (Procolobus pennantii pennantii) or Preuss's red colobus (Procolobus preussi), leading Ting (2008) to treat this monkey not as a subspecies of pennantii (see Groves 2001, 2005; Grubb et al. 2003) but as a distinct species, Procolobus epieni. Groves (2007) regarded almost all the different forms of red colobus monkeys, including epieni, pennantii and preussi as separate species, in the genus Piliocolobus.

There has been only one field study of this red colobus. Werre (2000) established that epieni occurs only in the socalled “marsh forest” zone of the Central Delta, an area that has a year-round high water table, but which does not suffer deep flooding or tidal effects. The study suggested that the more clumped distribution of food species in the marsh forest was a key factor restricting the monkey to its limited range, which is demarcated by the Forcados River and Bomadi Creek in the northwest, the Sagbama, Osiama and Apoi Creeks in the east, and the mangrove belt to the south. At the time of its discovery the Niger Delta red colobus was locally common, especially in forests near the town of Gbanraun, but it was beginning to come under intense pressure from degradation of its habitat and commercial hunting. Important colobus food trees—especially Hallea ledermannii—were being felled at a high rate by artisanal loggers, and the logs floated out of the Delta on rafts to processing centers in Lagos and elsewhere. In addition, large canals dug as part of oil extraction activities, as well as smaller canals dug by loggers into the interior swamps, were changing local hydrology (Werre and Powell 1997; Grubb and Powell 1999). The Ijaw people are traditionally fishermen but outside influences introduced by the oil industry have encouraged commercial bushmeat hunting and logging throughout the Niger Delta.

As part of his research Werre (2000) formulated a conservation plan that was initially to protect 500 ha of forest near the settlement of Gbanraun through a leasehold arrangement with community landholders. It was hoped that this could eventually be expanded to a full protected area based on the proposed Apoi Creek Forest Reserve. At present there are no formal protected areas in the Niger Delta, even though it has great ecological significance and supports many rare, unique and/or threatened taxa. The Niger Delta red colobus shares its marsh forest habitat with two other threatened primates; the Nigerian white-throated guenon (Cercopithecus erythrogaster pococki) and the red-capped mangabey (Cercocebus torquatus), each listed as Vulnerable on the Red List. Also found in these forests are the putty-nosed monkey (Cercopithecus nictitans), the mona monkey (Cercopithecus mona), and possibly the olive colobus (Procolobus verus). However, political instability in the Delta, related in the most part to disputes over the allocation of oil revenues, has prevented any progress in biodiversity conservation during the last decade. Because red colobus monkeys have been found to be highly vulnerable to habitat disturbance and hunting in other parts of Africa (Struhsaker 2005), it is feared that the Niger Delta red colobus is being driven to the edge of extinction.

The red colobus monkeys are probably more threatened than any other taxonomic group of primates in Africa (Oates 1996; Struhsaker 2005). Almost all those of western Africa are in a precarious position. Procolobus badius waldroni (eastern Côte d'Ivoire and western Ghana), Procolobus preussi (western Cameroon and eastern Nigeria), and P. pennantii bouvieri (Republic of Congo) are also now Critically Endangered. Procolobus badius temminckii (Senegal to Guinea or Sierra Leone), Procolobus badius badius (Sierra Leone to western Côte d'Ivoire) and Procolobus pennantii pennantii (Bioko Island, Equatorial Guinea) are listed as Endangered. There has been evidence of a few P. badius waldroni surviving in swamp forest in the far southeastern corner of Côte d'Ivoire (McGraw and Oates 2002; McGraw 2005), but it is feared that this population may now be extinct. Procolobus pennantii bouvieri of the Republic of Congo has not been observed alive by scientists for at least 25 years, raising concerns that they may be extinct (Oates 1996; Struhsaker 2005). Procolobus pennantii pennantii is just hanging on in the southwestern corner of Bioko Island, where it has been decimated by bushmeat hunting (Hearn et al. 2006) in what is, theoretically, a protected area.

Although the security situation in the Niger Delta is challenging, a pilot survey is planned for early 2009 to gather information on the present status of forest and primates near Gbanraun, and to assess what options may be available for conserving any remaining P. epieni. A survey is also urgently needed for Bouvier's red colobus in Congo. In all the protected areas where red colobus monkeys occur, much greater efforts must be made to improve management, especially the enforcement of laws against hunting.

John F. Oates & J. Lodewijk Werre

Kipunji

Rungwecebus kipunji (Ehardt, Butynski, Jones & Davenport in Jones et al., 2005)

Tanzania

(2006, 2008)

The discovery of the kipunji (Rungwecebus kipunji), a monkey endemic to southern Tanzania (Jones et al. 2005; Davenport et al. 2006), demonstrated how much there is still to learn about Africa's forests, as well as the continent's primate fauna. Kipunji were first found by teams working in the Southern Highlands and Udzungwa Mountains in 2003 and 2004, respectively (Jones et al. 2005; Davenport 2005, 2006; Davenport and Jones 2005; Davenport et al. 2005, 2006), sites that are some 350 km apart. Although initially placed in the genus Lophocebus (Jones et al. 2005), subsequent molecular and morphological analyses led to the monkey's placement in a new monospecific genus Rungwecebus, making it the first new genus of African monkey to be described in 83 years (Davenport et al. 2006). Further molecular studies have corroborated the validity of the genus (Olson et al. 2008) and anatomical investigations are under way.

More importantly, however, the kipunji is one of the world's most threatened primates, as demonstrated by a recent census that provided the first systematically-derived data on the animal's abundance and distribution (Davenport et al. 2008). Kipunji are cryptic, rare, primarily arboreal and in urgent need of conservation attention (Davenport et al. 2006; Davenport and Jones 2005), and consequently a complete count after a long-term survey was made, ensuring a much more accurate population estimate (Davenport et al. 2008). The census demonstrated that the kipunji is probably Africa's rarest monkey, and provided empirical data in support of its official designation as ‘Critically Endangered’ on the 2008 IUCN Red List, with the genus facing an extremely high risk of extinction in the wild (Davenport et al. 2008; Davenport and Jones 2008).

The kipunji is restricted to a number of discrete portions of the forests of Mt. Rungwe and the adjacent Livingstone (in Kitulo National Park) in the Southern Highlands, and the Vikongwa area of the Ndundulu forest (in the new Kilombero Nature Reserve) in the Udzungwa Mountains. The Mt. Rungwe-Livingstone population occupies degraded submontane and montane forest between 1,750 and 2,450 m above sea level, whereas the Ndundulu population lives between 1,300 and 1,750 m above sea level in submontane forest (Davenport et al. 2006, 2008). Kipunji have not been recorded in the Udzungwa Mountains National Park itself, the closest record being 1.9 km outside the park boundary (Jones 2006). Despite extensive surveys, kipunji have not been recorded from other forests in either the Southern Highlands or the Udzungwa Mountains.

During the census, a total of 34 kipunji groups were identified in the Southern Highlands with an estimated total population of 1,042. Of these, 501 individuals in 16 groups were counted in Mt. Rungwe and 541 individuals from 18 groups in the Livingstone forest of Kitulo National Park. In Ndundulu, just four groups were identified with an estimated total of 75 animals. The total global population of the kipunji therefore, is estimated to be just 1,117 animals, living in some 38 groups (Davenport et al. 2008). During the same surveys, the Areas of Occupancy (AoO) for Mt. Rungwe, Livingstone Forest and Ndundulu were estimated to be 671 ha, 408 ha and 199 ha, respectively. The total for Rungwe-Kitulo therefore was 1,079 ha, and the total species' AoO was 1,278 ha based on data collected over three years (Davenport et al. 2008). Meanwhile the Extents of Occurrence (EoO) for kipunji for Mt. Rungwe, Livingstone and Ndundulu were 815 ha, 425 ha, and 528 ha, respectively. The total for Rungwe-Kitulo was 1,241 ha and the total species EoO was estimated to be 1,769 ha (Davenport et al. 2008).

A total population of just 1,117 animals is very small. As reported elsewhere, both the Mt. Rungwe and Livingstone forests are heavily degraded (Davenport 2005, 2006; Davenport and Jones 2005) and remote sensing analysis of forest cover has demonstrated that the extent of habitat connection between the various groups is extremely tenuous. Indeed the Mt. Rungwe-Kitulo portion of the population consists of a number of isolated sub-populations and this is compounded by the poor condition of the narrow Bujingijila Corridor that joins Mt. Rungwe and Livingstone (Davenport 2005). With the loss of this corridor, the Mt. Rungwe-Kitulo population will be further fragmented. Furthermore, and in addition to the continuing loss of habitat, this population continues to be hunted (Davenport 2005, 2006; Davenport et al. 2005).

The fragile status of the population in Ndundulu is particularly worrying and its causes remain unknown. However, given current thinking on primate population sizes, it may be that this population is no longer viable (Davenport et al. 2008). The recent census also revealed an interesting and statistically significant difference in mean group size between the Rungwe-Kitulo and the Ndundulu populations (Davenport et al. 2008). This may be due to the small total population size in Ndundulu, or to fragmentation, reduced resource patches and food availability in Rungwe-Kitulo, as demonstrated in other primate species. Either way, the kipunji is more sparsely distributed than initially thought (Jones et al. 2005). The total EoO (species range) is just 17.69 km² giving grounds for much conservation concern, and being considerably less than the 100 km² required to fulfill the ‘Critically Endangered’ criterion of the IUCN Red List.

An estimated 541 individuals reside in Livingstone, a forest that has been incorporated into Kitulo National Park. This should significantly improve protection for the kipunji groups in this area, although the forest is severely degraded (Davenport 2006), and illegal activities, including logging and hunting of primates, are only now being brought under control. A new management plan for Kitulo National Park has recently been produced, in which the mandate for research and monitoring of the kipunji falls to the Wildlife Conservation Society (WCS). There are no immediate plans for habituation of the animal for tourism until appropriate and thorough research has been carried out on its potential impacts. However, a section of forest contiguous with Mt Rungwe, and containing groups of kipunji, is now being leased to, and managed by, WCS. The kipunji here are being studied and monitored full time by WCS staff as well as national and international students.

More than 51% of the total kipunji population lives in forests with comparatively little management. However, there are grounds for optimism. Ndundulu Forest Reserve was absorbed by the new Kilombero Nature Reserve in 2007 (Marshall et al. 2007) under the auspices of the Forestry and Beekeeping Division of the Ministry of Natural Resources and Tourism. Similarly, Mt. Rungwe, so long a neglected Catchment Forest Reserve, is now in the final stages of becoming a nature reserve as well. This will complement the adjacent national park and enable community involvement. A management plan is currently being written, and reserve rangers have recently been hired and trained. It will, however, be some time until illegal activities are brought under control, even with full resources at the authority's disposal.

On Mt. Rungwe, where forest clearance, hunting and fragmentation pose the most serious threats (Machaga et al. 2005), the reasons for the animal's discrete distribution are being studied. Moreover, research is being carried out on aspects of the kipunji's social and reproductive behaviour, feeding ecology, home range dynamics, predation and demography. Across Rungwe-Kitulo, the isolated sub-populations may already be subject to a loss of genetic variability due to low effective breeding populations. Some may no longer be viable and this is also under investigation.

Southern Ndundulu, meanwhile, is in excellent condition due chiefly to its remote location (Davenport and Jones 2005). However, the long-term viability of the 7% of the kipunji population must be considered uncertain, at best. It is possible that this population is simply dying out ‘naturally’, but research into the reasons for, and the viability of, the small Udzungwa population is ongoing. Whether any tangible primate conservation measures could or should be applied in a largely undisturbed habitat is debatable. The focus of applied kipunji conservation work is currently the protection and restoration of the montane forest habitats of Mt. Rungwe, widespread environmental education, and support to both management authorities and local communities across the range.

Tim R. B. Davenport, Noah E. Mpunga, Sophy J. Machaga, Trevor Jones, Claire E. Bracebridge & Daniela W. De Luca

Cross River Gorilla

Gorilla gorilla diehli Matschie, 1904

Nigeria and Cameroon (2000, 2002, 2004, 2006, 2008)

The Cross River gorilla (Gorilla gorilla diehli) is the most western and northern form of gorilla, and is restricted to the forested hills and mountains of the Cameroon-Nigeria border region at the headwaters of the Cross River. It is separated by about 300 km from the nearest population of western lowland gorillas (Gorilla gorilla gorilla), and by around 250 km from the gorilla population in the Ebo Forest of Cameroon. The most recent surveys suggest that between 200 and 300 Cross River gorillas remain. Groups of these gorillas concentrate their activities in 11 localities across a 12,000 km² range, though recent field surveys confirmed the presence of gorillas outside of their known localities suggesting a wider distribution within this range. This distribution is corroborated by genetic research, which has found evidence that many Cross River gorilla localities continue to maintain contact through the occasional dispersal of individuals.

There are many human settlements around the forests where the gorillas occur, including a number of enclaved villages within Okwangwo and Takamanda. The encroachment of farms, dry-season fires set to clear forest or improve pasture, and development activities, such as roads, continue to threaten the integrity of gorilla habitat. However, large tracts of lower elevation forest remain between the localities where the gorillas are presently concentrated, and if these areas can be protected, the animals may be able to expand their range and population size. Genetic evidence suggests that the decline in the population of Cross River gorillas has been recent, and is probably associated with the introduction of hunting with firearms. After several years of awarenessraising by conservationists and researchers, hunting of Cross River gorillas for bushmeat has been reduced to a low level, but it is still a potential threat, as are wire-snare traps set for other animals. A conservation action plan to improve the survival prospects for the Cross River gorilla was published in 2007 (Oates et al. 2007), and many of the key recommendations contained in the plan have already been implemented.

Key sites for the Cross River gorilla and the Ebo gorilla

Afi Mountain Wildlife Sanctuary (AMWS). AMWS is managed by the Cross River State Forestry Commission with support from a partnership of NGOs. Although levels of hunting have been reduced, the presence of more than 600 illegal farms within the sanctuary remains an unresolved problem. Widespread illegal logging in the contiguous Afi River Forest Reserve (ARFR) and the spread of farms from the intervening Buanchor enclave threaten to sever the habitat corridor linking Afi to the Mbe Mountains in the east. The sanctuary itself has been largely protected from logging due to its steep mountainous slopes, although the forest is frequently damaged by dry-season fires. Habituation of gorillas for the purposes of tourism is proposed, the potential costs and benefits of which are being debated. The sanctuary is also the proposed release site for the reintroduction of captive drills (Mandrillus leucophaeus) by the NGO Pandrillus.

The Mbe Mountains. The Mbe Mountains are a critically important corridor linking Afi Mountain to the west with Cross River National Park and the larger block of gorilla habitat to the east. Lacking any formal conservation status, traditional ownership of the Mbe forest is claimed by nine surrounding communities. In 2005, these communities formed the Conservation Association of the Mbe Mountains (CAMM) to manage the area both for conservation and to provide benefits to local communities. Capacity building and support for CAMM is currently provided by the local NGO Development in Nigeria, and an effective patrol system by a team of eco-guards has been established by the Wildlife Conservation Society (WCS). A protected area boundary has been provisionally demarcated, and the permanent demarcation and legal gazettement of this boundary is currently in progress. Although the mountains remain under threat from logging, agricultural encroachment and hunting, these threats have diminished somewhat since 2005.

Cross River National Park: Okwangwo Division. Cross River National Park (CRNP) is the most important site for Cross River gorillas in Nigeria and is contiguous with Takamanda in Cameroon. A number of new ranger posts have been constructed, and in 2008 all park rangers received basic training in anti-poaching techniques. Despite the efforts of park authorities, high levels of hunting occur in most areas of the Okwangwo Division (the northern sector of Cross River National Park where gorillas are found), driven by the lucrative bushmeat market. In addition, farmland belonging to three large village enclaves threaten to divide the park in two and thereby isolate the forest and gorillas of the ‘Boshi Extension’ in the extreme north from the rest of the Okwangwo Division. There have been recent efforts to promote transboundary collaboration between Okwangwo and Takamanda. Unfortunately, should the long-threatened privatization of national parks in Nigeria proceed as planned, the consequences for the remaining gorillas could be catastrophic.

Takamanda National Park. Originally established as a forest reserve in 1934, Takamanda was upgraded to a national park in November 2008. Takamanda's long history of use by local communities poses one of the biggest challenges to conservation in this area. The unsustainable harvesting of wildlife, certain non-timber forest products, and illegal timber extraction (from surrounding areas) must be brought under control. Many of these activities are driven by market forces in Nigeria, and a transboundary approach is essential to success. Despite these challenges, Takamanda and the adjacent Mawambi Hills located outside the southern boundary of the park provide refuge to a significant proportion of Cameroon's Cross River gorillas as well as scattered groups of drills (Mandrillus leucophaeus), chimpanzees (Pan troglodytes ellioti), Preuss's guenons (Cercopithecus preussi) and other large mammals. The area is also known to be of importance in terms of plant diversity, birds, reptiles and other taxa.

Mone River Forest Reserve. Mone was created as a Forest Reserve in the 1950s. Although there are no human settlements within the reserve, local people continue to harvest timber, wildlife, and other forest products. Due to a varied topography and rich vegetation, Mone still provides habitat for a number of large mammals, including Cross River gorilla in the northern half of the reserve (recent studies have confirmed that these gorillas are using an area larger than previously confirmed). In 2003, the government indicated that they might upgrade Mone to a Wildlife Sanctuary, and surveys have confirmed that this is urgently warranted. WCS in partnership with the UNEP/UNESCO Great Ape Survival Programme (GrASP) is to lead a feasibility study into carbon-based marketing for the area.

Mbulu forest. The Mbulu forest is a large block of unclassified forest which cloaks a series of extremely rugged and remote valleys located between the Kagwene Gorilla Sanctuary and northern Takamanda. Human population pressure is relatively low, with human activities being largely restricted to farming in valley bottoms and accessing the forest via ridges or less steep slopes for hunting and the harvesting of other forest products. Because of the relatively low human pressure, Cross River gorillas and other important species have found refuge here, and the forests of Mbulu provide one of the best opportunities to maintain some form of habitat corridor connectivity between various Cross River gorilla sites in the area. WCS is reviewing the possibility of establishing new protected areas and corridors, while at the same time working with villages adjacent to Cross River gorilla sites to establish a community-based gorilla protection and monitoring system known as the ‘gorilla guardian network.’

Kagwene Gorilla Sanctuary. Created in 2008, this sanctuary is the only protected area established specifically to conserve the Cross River gorilla. Although of limited size, Kagwene is home to a number of gorillas which are the subject of long-term research, monitoring and protection activities. Due to the daily presence of gorilla monitors, Kagwene is an important site for capacity-building related to gorilla monitoring and awareness-raising. In the near future, the Ministry of Forestry and Wildlife plans to post a warden and eco-guards to the Sanctuary, and will become increasingly involved in the financing of the site. Urgently required management measures include the demarcation of boundaries, recovery of farm-encroached forest, and integration of surrounding communities into management strategies. It is also important that forest corridor links with Mbulu are maintained.

Bechati-Fossimondi-Besali (BFB) Forest (now Lebialem-Mone Forest Landscape). The BFB Forest is about 40 km south of Mone and is the southernmost location of the Cross River gorilla. Though of limited size (c.120 km²), the BFB Forest is home to a likely small, but as yet unknown number of gorillas. In 2007, the Environment and Rural Development Foundation (ERuDeF) expanded gorilla research and conservation activities to Ndumbin-Nkandu and the Bechati-Mone Forest Corridor. In 2009, research activities will include the Mak-Betchou Forest, Nkingkwa Hills and Mbanga/Mpongo-Ebensuk Forest. ERuDeF also initiated community-based management activities to secure a future for great apes in the BFB Forest, where the main threats are habitat fragmentation and forest encroachment by small farmers, and hunting.

Ebo Forest. About 250 km south of the Cross River population and 5 km north of the Sanaga River, the Ebo Forest in southwestern Cameroon is home to a small isolated population of gorillas the taxonomic affinities of which are still unclear. The forest, which covers almost 2,000 km² and is adjacent to a large FSC-certified logging concession at its northern perimeter, is characterized by extreme topography and a diversity of habitats, and holds a unique assemblage of 11 diurnal primate species. Researchers from the Zoological Society of San Diego's Ebo Forest Research Project have been working in Ebo since 2005, and one of the three research stations is situated in the gorilla's range. Recent field research suggests that fewer than 25 individual gorillas survive in an area of about 25 km². The Ebo forest is also inhabited by important populations of other highly threatened species such as the drill (Mandrillus leucophaeus leucophaeus), Preuss's red colobus (Procolobus preussi) and the Gulf of Guinea chimpanzee (Pan troglodytes ellioti). The forest's primates are under extreme pressure from bushmeat hunting to supply the commercial trade, given the proximity of Ebo to the main urban centers in Cameroon. Over 1,000 km² of the Ebo Forest is currently being gazetted as a national park.

Aaron Nicholas, Andrew Dunn, Ymke Warren, Richard Bergl, Jacqueline Sunderland-Groves, Louis Nkembi & Bethan Morgan

Asia

Javan Slow Loris

Nycticebus javanicus É. Geoffroy, 1812

Indonesia

(2008)

All Asian lorises are imperiled by the devastating loss of their habitat; indeed, this major threat resulted in Sri Lanka's Critically Endangered Horton Plains slender loris appearing rightfully in the last two incarnations of this list (Nekaris 2006; Nekaris and Perera 2007). An even greater immediate threat to Asian lorises, however, is their high demand in the rampant Asian pet and traditional medicine trades (Schulze and Groves 2004; Streicher 2004). Easy to catch due to their slow locomotion, numbers of lorises in animal markets far outstretch the ability of these slow-reproducing primates to recover their population numbers in the wild (Shepherd et al. 2004). Indeed, this threat raised international concern, resulting in the transfer of all members of the genus Nycticebus to CITES Appendix I in 2007 (Nekaris and Nijman 2007). Five species of slow loris are now recognized: N. coucang (greater), N. pygmaeus (pygmy), N. bengalensis (Bengal), N. menagensis (Bornean), and N. javanicus (Javan) (Roos 2003; Chen et al. 2007). All slow lorises suffer from trade throughout their range, but when combined with tremendous habitat loss, no other species has been harder hit than the Javan slow loris.

Finally recognized by the IUCN as a species in 2006, and currently listed as Endangered, the Javan slow loris is distinguished easily from its congeners in several respects. Both morphologically and genetically, it is most similar to, yet still distinct from, the largest slow loris, N. bengalensis of mainland Asia (Roos 2003; Groves and Maryanto 2008). Weighing about 1 kg, the most distinctive feature of the Javan slow loris is its facial mask, comprised of bold fork marks leading from the eyes and ears to the crown of the head, revealing a white diamond pattern on the forehead (Nekaris and Jaffe 2007). Despite being legally protected since 1973, with its creamy neck, bold dorsal stripe, and panda-like face, it is no wonder that Indonesian pet traders in the 1990s targeted Javan slow lorises above other endemic loris species. Since 2002, however, the numbers of Javan lorises in trade have decreased, with a stark rise in numbers of Sumatran greater slow lorises, a species whose threat status must also be carefully monitored.

Nycticebus javanicus is found only on the Indonesian island of Java. Java has a long history of cultivation and deforestation that already started c.1000 AD, but really took off in 1830 when the Dutch colonial government imposed the so-called ‘cultuurstelsel’. To support this agro-economic system, farmers were forced to grow export crops on communal grounds, which were often forest (Whitten et al. 1996). By the end of the 19^th century the natural forest was severely fragmented, and at the beginning of the last century the remaining forest, especially in West and Central Java, showed a fragmentation pattern very similar to that seen today. Over the last few decades, the decrease in forest area has been slow. At present, less than 10% of the original forest remains, most of it covering the higher slopes of the central mountains.

GIS models have shown that historic forest loss and continued degradation mean that less than 20% of habitat suitable for N. javanicus remains. Species distribution modeling and a Gap Analysis have also revealed that only 17% of the potential distribution of N. javanicus is currently within the protected area network of Java. Furthermore, Thorn et al. (2008) have highlighted conservation priority areas for the increased protection of N. javanicus, based on GIS analysis and ecological niche modeling. These include recommendations for the extension of seven important protected areas across the island, as well as 11 priority survey sites where the current distribution and abundance of this enigmatic primate should be studied. More surveys are vital since the decreased number of Javan lorises in trade seems to correlate with exceedingly low numbers in the wild (Nekaris et al. 2008). Indeed, surveys by three research groups all showed animals to occur at 0.02 to 0.20 animals per km, when they could be found at all, meaning 5–10 km must be walked to see a single loris (Nekaris and Nijman 2008; Winarti 2008). Roads and human disturbance have been shown to correlate negatively with Javan slow loris abundance (Collins 2007; Winarti 2008).

Also urgently required are programs to mitigate trade in all species of slow loris. A number of studies have found that slow lorises are not always a targeted group, but that they do have economic value throughout their range. Rather than seeking a loris, villagers moving through the forest simply pick up a loris when they happen to see it (Starr et al. 2008). Similarly, when forests are clear cut (for agriculture or cash crops), villagers pick through the felled trees and collect the lorises; with a defense mechanism to cling to branches rather than to flee, and with their nocturnal senses stunned by bright daylight, lorises are an easy target (Ratjacsek 1998).

In Java itself, lorises are often specifically targeted for the trade (Sanchez pers. obs.). Local villagers who find a loris take it to a distributor dealer who compiles a stock of lorises. These animals go to middlemen who then distribute them throughout the “bird” markets in the main towns in Java. The traders who ultimately sell the animals are aware that trading lorises is profitable, reaching a price in the market up to ten times or more the purchasing price at the stocker's level.

Once they arrive at a market, lorises face other threats. To avoid being bitten by the purportedly toxic lorises, traders habitually cut or pull out an animal's front teeth. Most of these lorises die due to dental abscess or pneumonia. Those that do survive are no longer able to eat their preferred food (gum) (Wiens et al. 2006), or to engage in the important behavior of social grooming with the toothcomb, meaning that any confiscated animals are unlikely to survive if released to the wild. Reintroduction itself is a threat to the Javan loris; three major trade hubs, markets in Jakarta, Bandar Lampung and Palembang, receive lorises from throughout the region. The similar appearance of lorises to the untrained eye results in release of other loris species into Java, with potential for disastrous effects from hybridization or displacement by invasive species.

To combat the issue of trade, starting in 2002, a handful of foreign-aid assisted rescue centers were built up in Indonesia. These rescue centers became the haven for many different species of illegally traded wildlife confiscated by the Indonesian forest authorities, including hundreds of slow lorises. Up to 95–100% mortality of slow lorises has been reported by most rescue centers, due to untreated dental infections, improper care and malnutrition, as well as inappropriate releases. This problem is being combated with help from International Animal Rescue Indonesia (IARI), which set up the first facility specialized for the rescue and rehabilitation of lorises in Indonesia in 2006. Working closely with other NGOs, Indonesian Universities, and the Indonesian Ministry of Forestry, a Loris Rescue Unit is being set up to work on market investigations, rescue, rehabilitation and release of lorises, education and awareness, and supporting research work.

For a long time, slow lorises were thought to be common throughout Indonesia, and the presence of animals in trade was believed to be an indicator of their abundance. We are only beginning to unravel the complexity of their taxonomy and distribution, leading to an overall bleak picture. If trade cannot be halted, Critically Endangered will be a more apt listing for these evolutionarily distinct and beautiful primates. While Java has an impressive and comprehensive protected area network, encompassing over 120 terrestrial conservation areas covering some 5,000 km², enforcement of environmental laws and active protection of forest is lacking in most of these parks. Besides curbing the illegal trade, it is paramount that these conservation areas, and indeed all other remaining forest areas on the island, be effectively protected.

K. A. I. Nekaris, K. Llano Sanchez, J. S. Thorn, I. Winarti & V. Nijman

Simakobu or Pig-Tailed Snub-Nose Langur

Simias concolor Miller, 1903

Indonesia

(2002, 2004, 2006, 2008)

The simakobu monkey (Simias concolor) again is serving as the flagship species for the four Mentawai Island primates. The other three species inhabiting the 7,000 km² archipelago located west of Sumatra are Kloss's gibbon (Hylobates klossii), the Mentawai Island leaf monkey (Presybtis potenziani), and the Mentawai macaque (Macaca pagensis). Simias is a monotypic genus with two subspecies. Simias concolor concolor Miller, 1903 inhabits Sipora, North Pagai, and South Pagai Islands and several small islets off of South Pagai. Simias c. siberu Chasen and Kloss, 1927 occurs only on Siberut Island.

Very little has been published on simakobu behavior and ecology. The first activity budget of habituated simakobus described the activities of two groups living in the Betumonga region of southwestern North Pagai. The data show that simakobus spend almost equal amounts of time resting (46%) and feeding (44%), and less time moving (7%) (Paciulli and Holmes 2008). Wendy Erb is in the middle of a year-long study of male simakobu behavior, which should yield more complete data on basic activity patterns (pers. comm.).

New estimates of the amount of forest cover remaining on the Pagai Islands (about 826 km²) have been calculated using Google Earth Pro composite satellite imagery (Paciulli and Viola 2009). The forest cover coupled with primate density data (Paciulli 2004) indicate that there are approximately 3,347 simakobus, 1,049 Kloss's gibbons, 1,545 leaf monkeys, and 7,984 pig-tailed macaques on the Pagai Islands. All of the primate species seem to reach their highest known densities in the Peleonan Forest, site of the Siberut Conservation Project in northern Siberut (Waltert et al. 2008).

The 190,500-ha Siberut National Park, a UNESCO Biosphere Reserve, covers 47% of Siberut Island and serves as the main reserve for the Mentawai primates. The large majority of the other remaining natural habitat lies outside officially protected areas. Most of these areas are subjected to human encroachment, product extraction, commercial logging, and conversion to cash crops and oil palm plantations (Whittaker 2006). Although hunting appears to be declining and opportunistic in many areas of the Pagais, where it still occurs it has devastating effects on S. concolor, the preferred game species (Mitchell and Tilson 1986; Fuentes 2002; Paciulli 2004). In addition, S. concolor seems to be particularly sensitive to logging, having 5 individuals/km² in unlogged Pagai forests to half that amount (2.5 individuals/km²) in Pagai forest patches logged 20 years earlier (Paciulli 2004). Drastic measures need to be taken to ensure that the Peleonan Forest on Siberut and areas on the Pagais are truly protected.

Lisa M. Paciulli

Delacour's Langur

Trachypithecus delacouri (Osgood, 1932)

Vietnam

(2000, 2002, 2004, 2006, 2008)

Delacour's langur, also known as the white-rumped black leaf monkey, is endemic to Vietnam, occurring in a very restricted area in the north of the country that comprises about 5,000 km² between 20°–21°N and 105°–106°E. The distribution is closely related to the limestone mountain ranges in the provinces Ninh Binh, Thanh Hoa, Hoa Binh, and Ha Nam. Currently there are 18 locations known where Delacour's langurs occur. They are isolated populations, and combined total at most only 400 to 450 km². We know of five localities where local people have reported that it has been extirpated. The northwestern border of the distribution is Mai Chau, between the Da River in the north and the Ma River in the south. The Da River seems to form the northern border of the species' range, but the exact southern boundary is unclear. There are a number of isolated limestone areas south of the Ma River, but the only location where they are known there is the limestone complex between Lang Chan and Ngoc Lan. This population is, however, now most probably extirpated. It seems that this species never occurred south of the Chu River.

During the decades following the discovery of Delacour's langur in 1930 there was only scanty information on its existence and distribution. The first sightings of live animals were reported in 1987 from Cuc Phuong National Park. The most important and for some subpopulations the only factor for the decline in numbers is poaching, which is not primarily for meat, but for bones, organs and tissues that are used in the preparation of traditional medicines. The 18 isolated wild populations of Delacour's langur have been confirmed over 10 years of surveys and monitoring by the Frankfurt Zoological Society. The total population counted in 1999/2000 was about 280 to 320 individuals. The recorded numbers of animals hunted over the 10 years (1990 to 1999) totaled 320, an annual loss of more than 30 individuals, but the real number is undoubtedly higher. Sixty percent of all existing Delacour's langurs occur in isolated populations with less than twenty animals. The loss of these subpopulations, and consequently 60% of the entire population, is foreseeable without management, strict regulations and law enforcement. Surveys in 2004 in two protected areas with important subpopulations — Cuc Phuong National Park and Pu Luong Nature Reserve — showed a decline in numbers of 20% in 5 years (2000 to 2004). Surveys were carried out in 2008 by the Frankfurt Zoological Society in search of possibilities to translocate small isolated populations under severe threat. The results of the surveys show a continuously dramatic decline. The population in Ngoc Son Nature Reserve is most probably extirpated, the population in Pu Luong Nature Reserve reduced by about 25%, and the population in Cuc Phuong National Park reduced to 8 to 11 individuals. It is to be expected that the population in unprotected areas which have yet to be surveyed will show a similar tendency. A reasonable estimate of the current population indicates no higher than 200 individuals. Surveys by the Frankfurt Zoological Society continue, and should provide background information about status of populations and logistics for translocation. The improvement of protection for most of the subpopulations is not a realistic option, and most subpopulations are already too small for recovery without active management.

Four areas where Delacour's langurs occur are protected: Cuc Phuong National Park, Pu Luong Nature Reserve, Hoa Lu Cultural and Historical Site, and Van Long Nature Reserve. Van Long Nature Reserve is believed to harbor the largest remaining population. Delacour's langurs there are well protected due to close cooperation between the provincial forest protection authorities and a local guard unit paid and trained by the Frankfurt Zoological Society. Since the establishment of the Nature Reserve in 2001, the population of Delacour's langurs has grown by about 35%, and currently numbers 80 to 90 individuals. Efforts to save this species are one focus of the Vietnam Primate Conservation Program of the Frankfurt Zoological Society and the Endangered Primate Rescue Center at Cuc Phuong National Park, established in 1993 primarily to safeguard the future of this and other endangered Vietnamese primates. The Endangered Primate Rescue Center is the only facility which keeps this species. The center started a breeding program with five confiscated animals, and 15 individuals have been born since 1996. The aim is to reintroduce these langurs into well-protected areas to establish additional free ranging populations.

Tilo Nadler

Golden-headed Langur or Cat Ba Langur

Trachypithecus p. poliocephalus (Trouessart, 1911)

Vietnam

(2000, 2002, 2004, 2006, 2008)

The golden-headed langur, Trachypithecus p. poliocephalus, is probably the most endangered of the Asian colobines. This subspecies occurs only on the Island of Cat Ba in the Gulf of Tonkin, northeastern Vietnam. The Cat Ba Archipelago is in the world-famous Ha Long Bay, a spectacular karst formation that was invaded by the sea. The golden-headed langur inhabits tropical moist forest on limestone karst hills, and shares this habitat preference with the other six to seven taxa of the T. francoisi group. These so called karst langurs, including the Cat Ba langur and its closest relatives, the white-headed langur, T. p. leucocephalus Tan, 1955, in southern China, display strict behavioral adaptations to their karst habitat.

There are no systematic and reliable data available on the historic density of the langur population on Cat Ba Island. According to reports of indigenous people the entire island of Cat Ba (140 km²) and some smaller offshore islands were previously densely populated by langurs. Hunting has been the sole cause for the dramatic and rapid population decline from an estimated 2,400–2,700 in the 1960s to only 53 individuals by 2000. The langurs were poached mainly for trade in traditional medicines. Since the implementation of strict protection measures towards the end of 2000, the langur population on Cat Ba Island increased to current 60–70 individuals.

Although the growth of the population is encouraging, the overall status of the subspecies is most critical. As a result of habitat fragmentation, the remaining population is now divided into seven isolated sub-populations, probably only four of which include males, while the others are all-female groups and thus non-reproducing social units. The total reproductive output in this species is accordingly low. Since a peak in births in 2003, the reproductive output of the Cat Ba Langur has stagnated at 1–2 offspring per year.

Cat Ba Island and the surrounding area are nationally and internationally recognized for their importance to biodiversity conservation. Cat Ba National Park was established in 1986. It presently covers more than half of the main island. The Cat Ba Archipelago (some 1,500–2,000 large and small islands, cliffs and rocks) was designated a UNESCO Man and the Biosphere Reserve in 2004.

Despite this, nature and wildlife protection on Cat Ba Island is deficient, though awareness as well as partnership and commitment with the local communities are slowly increasing. However, efforts to effectively conserve the langurs and their habitat face major obstacles due to the need to better address the local community's aspirations for development, and due to the steadily increasing human population, besides persistent, severe deficiencies in law enforcement. As elsewhere in the region, poaching is driven by increasingly attractive commercial gains in satisfying the immense local and regional demand for wildlife and animal parts. The strictest protection regime possible is necessary for the survival of all the mammals and other species on Cat Ba that are, like the langurs, targeted by the Asian wildlife trade.

A conservation program for the golden-headed langur on Cat Ba was initiated in November 2000 by the Zoologische Gesellschaft für Arten- und Populationsschutz (ZGAP), München, and Allwetterzoo Münster, Germany. The aim is to provide for their protection, reduce population fragmentation, and contribute to the conservation of the biodiversity on Cat Ba Island in collaboration with Vietnamese authorities.

Daniela Schrudde, Roswitha Stenke, Phan Duy Thuc & Martina Raffel

Western Purple-faced Langur

Trachypithecus (Semnopithecus) vetulus nestor Bennett, 1833

Sri Lanka

(2004, 2006, 2008)

One of the most serious problems facing Sri Lanka's western purple-faced langur (T. v. nestor) stems from the fact that it inhabits some of the most densely populated regions of the country. As a result, this endemic monkey's long-term survival is severely threatened by unplanned and haphazard urbanization. A recent survey involving nearly 1,900 km of travel through one-third of T. v. nestor's historical range (Hill 1934) showed that nearly 81% of the areas surveyed consisted of deforested and human-dominated landscapes. Another analysis indicated that more than 90% of its entire range has been replaced by houses, home gardens, townships, temples, schools, plantations, commercial operations and other areas of human activity. Deforestation has fragmented and drastically depleted the preferred habitat and principal food sources of the highly arboreal and folivorous T. v. nestor.

Within the fragmented and human-dominated landscape, T. v. nestor subsists mainly on fruits from home gardens (Dela 2007; Rudran 2007). The nutritional consequences of feeding on a low diversity diet mainly of cultivated fruits are unclear, but likely to be detrimental over the long term, because T. v. nestor is adapted to obtain its nutrients and energy from leaves with the help of a highly specialized stomach containing symbiotic bacteria (Bauchop and Martucci 1968). Given these specializations, relying on a diet of fruits instead of leaves may undermine the functioning of this monkey's gut fauna and thereby compromise its ability to absorb nutrients. Furthermore, fruits tend to occur seasonally, which means that T. v. nestor may not be able to fully satisfy its energy requirements outside the fruiting season. When such detrimental effects have the potential to affect this langur through most of its range, its long-term survival becomes an issue of serious concern.

Besides depleting T. v. nestor's primary food source and preferred habitat, deforestation and fragmentation also cause other problems for this monkey's survival. For instance, when fragmentation forces it to move on the ground, for which it is ill-adapted, people will occasionally capture young individuals to raise them as house pets. While on the ground T. v. nestor also runs the risk of being killed by domestic dogs or speeding vehicles. Death by electrocution is another source of mortality when it climbs onto power lines and electricity cables (Parker et al. 2008). In some parts of its range T. v. nestor is occasionally shot and killed while feeding in home gardens (Dela 2004). Deforestation and fragmentation indirectly lead, therefore, to a host of human-induced fatalities, which reduce group sizes and undermine social organization.

The long-term effect of extensive deforestation resulting in local extinctions was also evident during the recent survey. The western purple-faced langur was seen or recorded as present only in 43% of the sites surveyed in the eastern half of its historical range (N = 23), and 78% of the survey sites in the western half (N = 27). The sites where it was seen or recorded as present were interspersed between areas where it was absent or rare, suggesting the occurrence of local extinctions.

Although facing a perilous future, certain facts revealed during the recent survey indicate that it is still possible to save this monkey from disappearing forever. The largest forests it now inhabits (about 21 km² in all) are found around two reservoirs (Kalatuwawa and Labugama) that supply water to 1.2 million inhabitants of Sri Lanka's capital, Colombo. Because of their importance to people and their size, these forests are the last and most secure strongholds for maintaining viable populations over the long term. The Forest Department responsible for these forests has indicated interest in replanting the pine plantations in them with native species that are exploited by T. v. nestor. Such an initiative would certainly increase the extent of T. v. nestor's preferred habitat, but it would first require a study of this langur's dietary preferences in the wild, which have yet to be studied.

Another important fact that surfaced during the survey was that the Forest Department has plans to promote forest conservation among communities living around its forests, through environmental education and nature tourism programs. Such programs can help conserve T. v. nestor, but to be effective they must be translated into action almost immediately.

Most people living within this langur's range were found to be Buddhists, who have a strong aversion to killing animals. The Buddhist taboo against killing may explain why this monkey has survived for as long as it has in such a densely populated area despite its reputation as an agricultural pest and a nuisance causing damage to roofs of houses and other properties. Sporadic killing does occur, however, as conflict between humans and monkeys intensifies (Nahallage et al. 2008), and poverty plagues the lives of the local people. Despite this situation, our survey revealed at least two forested sites around Buddhist monasteries where the incumbents strictly enforced the principles of their faith and protected T. v. nestor and other wildlife. Hence soliciting the support of the Buddhist clergy and using cultural traditions to protect wildlife is a real possibility in Sri Lanka.

The above mentioned facts indicate that opportunities still exist for conserving T. v. nestor, despite the survival problems of this endangered endemic. The survey led to the development of a comprehensive plan for conserving T. v. nestor that includes three initiatives; public education, personnel training, and research. Because of the urgent need for conservation action, some elements of these initiatives were launched immediately after the survey despite the paucity of funds.

The public education initiative was launched at two sites that were identified as important for the long-term conservation of T. v. nestor, and targeted rural communities, particularly school children and their parents, living close to them. One site was around the Labugama-Kalatuwawa reservoirs where a viable population of T. v. nestor could be maintained over the long term, and the other was an area where humanmonkey conflict was particularly intense. The educational activities at both sites were conducted with the support and participation of local Buddhist temples and clergy, and culminated in a public exhibition of conservation-oriented children's paintings and essays, at which the country's Minister for Environment and his top bureaucrat awarded prizes to the most talented youngsters. These events were publicized via newspaper articles and radio talk-shows to inform a much larger audience throughout the island that efforts to help conserve T. v. nestor were supported by the government and influential officials of the country.

The training initiative was launched with a series of activities designed to help a group of six trainees learn about the biology and identification of Sri Lanka's primates, birds and butterflies. Similar workshops dealing with plants, land snails, reptiles, amphibians and invasive species have been scheduled for the future. The primary objective is to train local youth, particularly those living around the Kalatuwawa-Labugama reservoirs, to become well-informed naturalists, who could work independently as nature guides or with us to help conserve T. v. nestor

The research initiative remains dormant for the moment due to a lack of funds, but proposals have been submitted to address this shortcoming. When funds become available, research on T. v. nestor's ecology and behavior, particularly its dietary preferences in the wild, will begin, and the work on the public education and training initiatives will be expanded. The battle to win the hearts and minds of people and to help ensure the survival of T. v. nestor has only just begun. Much remains to be done, and success can be achieved if this battle is sustained until current trends of deforestation are reversed, and people become more aware of the value of their wildlife.

Rasanayagam Rudran, Kanchana Weerakoon & Ananda Wanasinghe

Gray-shanked Douc Monkey

Pygathrix cinerea Nadler, 1997

Vietnam, Cambodia (?), Laos (?)

(2000, 2002, 2004, 2006, 2008)

The colobine monkeys of the genus Pygathrix are native to Indochina. Until only ten years ago, just two distinct taxa were recognized: the red-shanked douc, Pygathrix nemaeus (Linnaeus 1771), in the northern part of Central Vietnam and Central Laos; and the black-shanked douc, P. nigripes (Milne-Edwards, 1871) from South Vietnam and east Cambodia. The gray-shanked douc was first described as a subspecies of the red-shanked douc, but genetic studies have since demonstrated a divergence at species level (Roos and Nadler 2001). It occurs in Central Vietnam between 13°30′ and 16°N, and has been recorded in five provinces: Quang Nam, Quang Ngai, Kon Turn, Gia Lai, and Binh Dinh. Currently, gray-shanked doucs are known only from Vietnam, but records exist close to the border with Laos, and there are photos of hunted animals from south-east Laos and far north-east Cambodia that suggest that the species occurs in small neighboring areas in both countries. Surveys and research on this recently discovered primate have been conducted by the Vietnam Primate Conservation Program of Frankfurt Zoological Society, and the Endangered Primate Rescue Center at Cuc Phuong National Park.

Gray-shanked douc populations are fragmented, and estimated to total 600–700 individuals. Their occurrence has been confirmed in eight protected areas: Song Thanh Nature Reserve, Ngoc Linh Nature Reserve, Ba To Cultural and Historical Site, An Toan Nature Reserve, Kon Cha Rang Nature Reserve, Kon Ka Kinh National Park, Mom Ray National Park and A Yun Pa Nature Reserve. Hunting—the principal threat to the species—is, however, still a problem inside these parks and reserves. Snares are the most commonly-used method since gun confiscation programmes were carried out in a number of the areas. Often hundreds of traps are installed in trees frequently used by the monkey groups, as well as on the ground where they are seen crossing between small forest patches. Trapped animals are often severely injured and mutilated. Forest loss within at least part of the species' range is attributable to the expansion of agriculture, illegal logging and firewood collection. Almost 10,000 ha of forest are selectively logging every year in the Central Highlands.

The Endangered Primate Rescue Center has received 37 confiscated gray-shanked douc monkeys since 1995, and has begun a breeding program to provide stock for reintroduction in protected forests. Based on information from villagers and forest protection authorities, less than one-quarter of the hunted animals are confiscated alive. Frankfurt Zoological Society is studying the species in the Central Highlands of Vietnam, specifically to provide recommendations for the establishment of special “Species Protection Areas”, which will promote connectivity between the currently-isolated populations in the established parks and reserves.

Ha Thang Long & Tilo Nadler

Tonkin Snub-nosed Monkey

Rhinopithecus avunculus Dollman, 1912

Vietnam

(2000, 2002, 2004, 2006, 2008)

The Tonkin snub-nosed monkey is one of four unusual, large, Asian colobine monkeys of the genus Rhinopithecus, all of which possess a characteristic turned-up nose. The three other species are endemic to China, while the Tonkin snub-nosed monkey is found only in northeastern Vietnam. This species was discovered in 1911, collected on perhaps no more than two occasions over the course of the subsequent 50 to 60 years, and consequently presumed to be extinct by a number of primatologists until it was rediscovered in 1989. Historically the species occurs only east of the Red River between about 21°09′–23°N. Due to widespread deforestation and intensive hunting in recent decades, its distribution has become severely restricted.

Currently, there are only five known locations with recent evidence where Tonkin snub-nosed monkeys occur, and these are completely isolated. In 1992, a population was found in Na Hang District, Tuyen Quang Province. As a result of the discovery, a nature reserve was established in 1994. The nature reserve comprises two separate areas: the Tat Ke and Ban Bung sectors. A study in 1993 observed 72 individuals and estimated 80 in the Tat Ke sector, and observed 23 individuals and estimated 50 in the Ban Bung sector. A later study, in 2004–2005, found far lower densities, and estimated only 17–22 individuals in the Tat Ke sector; no estimation of numbers was possible for the other subpopulation in Ban Bung sector. The main threat to the monkeys in Tat Ke Sector was hunting. This may result from a hydropower and flood prevention dam project in Na Hang. Construction began in 2002, and some 10,000 workers moved into the area for dam construction. This created a number of access roads and a demand for wildlife products and firewood. Conservation activities carried out by several organizations have been unsuccessful, and it has resulted in a reduction of this population.

A population of about 70 individuals was estimated for Cham Chu Nature Reserve in 2001, also in Tuyen Quang Province. Based on interviews of local people during a survey that was reported in 1992, the population was believed to have dropped to only 20–40 individuals. A survey in 2006 provided no sightings and no reliable evidence of the survival of the population. Local reports indicate, however, a small group of 8–12 individuals still in the area. The current threats to the populations of the monkeys are hunting and habitat destruction. Conservation efforts should target reducing human activities inside the reserve.

A population of about 60 Tonkin snub-nosed monkeys was discovered in 2001 and a later study (2005–2006) confirmed about 90 animals in Khau Ca, close to Du Gia Nature Reserve, Ha Giang Province. This is the only population which is not immediately threatened. There, public awareness and community participatory activities are being linked to increased protection efforts under the supervision of Fauna and Flora International (FFI).

A new population of about 20 Tonkin snub-nosed monkeys was discovered in a small forest patch in Tung Vai Commune of Quan Ba District close to the border with China. This is the second population of Tonkin snub-nosed monkey discovered in Ha Giang Province. The newly discovered population at Tung Vai appears to be threatened by hunting and habitat loss due to timber exploitation, shifting cultivation and the collection of non-timber forest products for commercial purposes. The immediate measures are likely to be training and establishing patrol groups, awareness-raising, more survey work to locate other groups and assess the range of the monkeys, and assessment of the impact of cardamom production on the habitat.

The total population of the Tonkin snub-nosed monkey is believed to be less than 200 individuals.

Le Khac Quyet, Dong Thanh Hai & Tilo Nadler

Eastern Black Crested Gibbon

Nomascus nasutus (Kunkel d'Herculais, 1884)

China, Vietnam

(2008)

The eastern black crested gibbon occurs in a very restricted area along the Sino-Vietnam border, comprising only about 48 km², around 22°55′N, 106°30′E, including the northern Phong Nam-Ngoc Khe forests (about 30 km²) of Trung Khanh District, Cao Bang Province, Vietnam, and an immediately adjacent area (about 18 km²) in Jingxi County in South China's Guangxi Zhuang Autonomous Region (La Quang Trung and Trinh Dinh Hoang 2004; Chan Bosco Pui Lok et al. 2008).

In the past, the species was believed to comprise two subspecies (N. nasutus nasutus and N. n. hainanus), the first occurring in Vietnam and the second on China's Hainan Island. Both have now been elevated to full species, based initially on differences in territorial calls and fur coloration (La Quang Trung and Trinh Dinh Hoang 2004), but supported by genetic data (Roos et al. 2007). At the 2006 Asian Primate Red List Workshop in Cambodia, both were recognized as distinct species (Geissmann 2007; Chan et al. 2008). The historical range of the eastern black-crested gibbon was east of the Red River in China and Vietnam. It was thought to have gone extinct over its historical range in mainland China (Tan 1985), but was rediscovered recently in Bangliang Limestone Forest in Jingxi County; the population was estimated at 19 individuals, living in three groups (Chan Bosco Pui Lok et al. 2008). In Vietnam, it was also feared extinct until scientists from Fauna and Flora International (FFI) rediscovered a population in the limestone forest of Phong Nam-Ngoc Khe Communes in the northernmost Trung Khanh District, Cao Bang Province, northeast Vietnam, along the border with Guangxi. The population was estimated to be 26 individuals in at least five groups, based on a survey conducted in August 2002 (Geissmann et al. 2002, 2003), and 37 individuals in 8 groups in a survey in September 2004 (Trinh Dinh Hoang 2004). Based on simultaneous surveys in September 2007 on both sides of the border, the total population of the gibbon is around 110 individuals living in 18 groups (Le Trong Dat et al. 2008). Thus, the species should be listed as Critically Endangered.

Nomascus nasutus inhabits lower montane and limestone forests in a wet tropical monsoon climate at elevations of 500–900 m (Geissmann et al. 2000). The main threat to this species, given its restricted range, is habitat loss and disturbance. The habitat of N. nasutus is in danger of being cleared for cultivation, pasture for livestock, and firewood collection by local Vietnamese, as well as charcoal-production by local Vietnamese and Chinese. The species is also endangered from problems intrinsic to small population size such as inbreeding effects, poor mate-choice, and human or natural disaster (La Quang Trung and Trinh Dinh Hoang 2004).

Conservation efforts on this species have been initiated in China since its rediscovery two years ago. Work on a proposed nature reserve to protect the gibbons, including comprehensive surveys and official document preparation, is now in progress, and the reserve will soon be in place. As for its conservation in Vietnam, Fauna and Flora International (FFI), along with Cao Bang FPD, is spearheading the establishment of a Species Conservation Area and a joint forest protection system that involves communities, a ranger force, and border patrol. FFI is also partnering with the Cao Bang Rural Development Project to encourage sustainability and conservation education and research in the local communities of the region (La Quang Trung and Trinh Dinh Hoang 2004). There is an urgent need to integrate the conservation efforts of both countries if the species is to be saved.

Long Yongcheng & Tilo Nadler

Western Hoolock Gibbon

Hoolock hoolock (Harlan, 1831)

Bangladesh, India, Myanmar

(2009)

Western and eastern hoolock gibbons were formerly in the genus Bunopithecus as two subspecies. In 2005, Mootnick and Groves placed them in a new genus, Hoolock as two distinct species, the western being Hoolock hoolock and the eastern, Hoolock leuconedys. The western hoolock gibbon occurs in India, Bangladesh and Myanmar, and the eastern hoolock gibbon in India, Myanmar and China.

The range of western hoolock gibbon is strongly associated with contiguous canopy, broad-leaved, wet evergreen and semi-evergreen forests. Hoolock gibbons are important seed dispersers, their diet including mostly ripe fruits, with some flowers, leaves and shoots.

Western hoolock gibbons face numerous threats, and now may be dependent on human action for their survival. Threats include habitat loss due to human encroachment, forest clearance for tea, slash-and-burn cultivation, hunting as food and medicine, and capture for trade. Additional threats include decline in forest quality which affects fruiting trees, canopy cover and the viability of their home ranges. Isolated populations face additional threats arising from intrinsic effects of small populations. Some populations surviving in a few remaining trees are harassed by locals and dogs while attempting to cross clearings between forest patches in search of food.

Habitat loss over the last 3–4 decades suggests that western hoolock gibbons have declined from more than 100,000 to less than 5,000 individuals (a decline of more than 90%). The contiguous forests have borne the brunt of persistent human impacts. Isolated forest fragments hold a few families of about 1–4 individuals; numbers insufficient for long-term survival. Apart from some border forests between India and Myanmar, the remaining habitat is fragmented, holding minimal populations. The extirpation of western hoolock gibbons from 18 locations between 2001 and 2005 has been documented; ten in India and eight in Bangladesh.

About 100 locations of western hoolock gibbons have been recorded in India. In 2005, 77 of those locations had less than 20 individuals, and 47 of these had less than 10. A Population Viability Analysis (PVA) predicted a 75% decline in the population in India and a 95% decline in the population in Bangladesh over the next two decades, based on the current effects of human impacts.

Earlier estimates of western hoolock gibbons in Bangladesh were about 200 in 22 separate locations. Anwar Islam and his team conducted site visits in additional areas since then, and now estimate a total of about 300 individuals comprising 82 groups in 37 sites. In northeastern Bangladesh there are 12 sites with 102 hoolocks. The rest are in 25 sites in the southeast. There may be populations numbering 50–100 individuals in remote areas of the southeast hill tracts, but this has not been confirmed because of inability to visit these sites due to insurgency. During the last 15 or so years, hoolock gibbons have been extirpated from many sites, including Chunati Wildlife Sanctuary in the southeast. The extent of degradation and fragmentation of hoolock gibbon forests in the country is severe and the available habitats are continuing to decline.

The southernmost population of the western hoolock gibbon in Myanmar has been surveyed by Geissmann et al. confirming the presence and identification of western hoolock gibbon (Hoolock hoolock) in southern Rakhine Yoma, Myanmar, albeit a very small number. Reports of several other surveys in southern Myanmar are pending (Geissmann et al. 2008).

There may be much yet to learn about the distribution of the two species of hoolock gibbons. J. Das et al. identified the eastern species from Lohit district of Arunachal Pradesh, India, for the first time in 2005. Also, in a study conducted in the early months of 2009, D. Chetry found a new population of Hoolock leuconedys of around 150 groups between the rivers Dibang and Lohit in Lower Dibang Valley District of Arunachal Pradesh, India.

Warren Brockelman has carried out surveys of the eastern hoolock, Hoolock leuconedys in two accessible protected areas east of the Chindwin River in Myanmar since 2005. Recent studies in Mahamyaing Wildlife Sanctuary, western Myanmar, using auditory sampling of groups, produced an estimate of about 6,000 individuals and a mean density of more than 2 groups/km² in areas of suitable forest. Preliminary analysis of a survey by WCS—Myanmar and Wildlife Department personnel farther north in the Hukaung Valley (Kachin State) suggested that thousands of hoolocks survive there also. The Hukaung Valley Wildlife Sanctuary includes the headwaters of the Chindwin River and is contiguous with areas in India. The area of evergreen forest in the Hukaung Valley Reserve and contiguous PAs is so large (more than 20,000 km²) that the population there is likely to be in the tens of thousands. If so, this represents the largest population of hoolocks anywhere. Nevertheless, these PAs are not well protected and it is hoped that current interest in conservation in this multiple-use area will be sustained.

Eastern hoolock gibbons also occur in China. According to Fan Pengfei, a Chinese field biologist, the Chinese eastern hoolock gibbons survive only in Gaoligongshan Nature Reserve (GNR) in Baoshan, Tengchong, and Yingjiang. Based on field surveys, population size in GNR was estimated to be 20–21 groups. There are about 15 groups living outside Gaoligongshan Nature Reserve (based on interviews). The total population size is estimated to less than 150 individuals and is severely fragmented. The largest subpopulation in Yunnan has 8–10 groups; the second largest subpopulation has four groups, and in several sites there are only single groups. Twenty years ago researchers estimated the population size of hoolock gibbons to be less than 200. This was a low estimate due to failure of research to cover all distribution areas. The hoolock gibbon is threatened by poaching in some places and by habitat degradation and fragmentation outside GNR. There are no records of western hoolock gibbons in China to date.

There has been serious concern about the survival of hoolock gibbons for some decades. The species was listed on Schedule I, the highest schedule, on the Indian Wildlife (Protection) Act in 1972. It is categorized as Endangered on the IUCN Red List. The western hoolock gibbon was designated as one of the top 10 threatened gibbon taxa of the world in a Resolution taken in the gibbon symposium of the Congress of the International Primatological Society at Beijing in 2002.

Hoolock gibbons were assessed along with other South Asian primates at a Conservation Assessment and Management Plan workshop held in Coimbatore in 2002. Participants from northeastern India and Bangladesh assembled detailed locality tables which painted a bleak picture for western hoolock gibbons. Participants recommended that a Population and Habitat Viability Assessment (PHVA) Workshop should be conducted for the species. In 2005, a PHVA workshop was conducted for Hoolock hoolock in Dhaka, Bangladesh. Among other recommendations, workshop participants suggested that small, isolated, doomed individuals and groups in degraded areas should be translocated to more supportive habitat within their range.

The level of local knowledge required to conduct successful wild-to-wild translocations needed supplementation, so a collaborative initiative between GOs and NGOs in India and Bangladesh for scoping and training in translocation was organized. Two workshops, held in September 2008 for all stakeholders from India and Bangladesh, and February 2009 for senior foresters or their representatives from India generated a great deal of interest as well as a new awareness of the subtleties of such an exercise. Tentative plans were made for each state at the workshop. Arunachal Pradesh has taken the initiative and engaged the Wildlife Trust of India to assist them with an exercise for several isolated groups in an agricultural field in the state. Other northeastern Indian states and Bangladesh are also considering conducting carefully planned and executed translocations. The CAMP, PHVA and translocation training workshops also generated considerably more public awareness activities on hoolock gibbon that are now taking place very regularly, which will be useful also to the translocations when they occur.

There are hundreds of western hoolock gibbons languishing as single individuals or in minute groups in the northeastern Indian states and in Bangladesh. Successfully translocating these to more viable locations in nearby larger areas with resident, established hoolock populations will not only enrich the gene pool and strengthen populations but also salvage animals and their genetic material that would not otherwise survive even a very few years. Such an exercise will also provide a platform with a remarkable profile for enhancing protection as well as for reclaiming and restoring forest patches to create more contiguous habitat for hoolocks. It should also create good will and interest by the public, whose cooperation is necessary for long-term success. However, such exercises should be undertaken with strict adherence to the IUCN/SSC Reintroduction Specialist Group (RSG) reintroduction guidelines. They should also be a “last resort”, after exploring all other means of conserving both habitats and species, working with locals in the current areas.

The population trends for the western hoolock gibbon observed over recent years in Bangladesh and northeastern India indicate a very rapid decline in numbers for which very little has been done in the way of mitigation. Immediate measures are required by governments, forest departments, local communities and NGOs to limit habitat destruction, initiate or improve habitat restoration and upgrade implementation of protective measures. Although there are indications of increased numbers in this report, it is only because more localities or areas are being visited and found to have hoolock gibbons sometimes in significant numbers. This should not, in any way, lead to complacency but to greater efforts to see that the threats which have plagued the hoolock gibbon in the past 3–4 decades are addressed and contained.

Sally Walker, Sanjay Molur, Warren Y. Brockelman, Jayantha Das, Anwarul Islam, Thomas Geissmann & Fan Peng-Fei

Sumatran Orangutan

Pongo abelii Lesson, 1827

Indonesia (Sumatra)

(2000, 2002, 2004, 2006, 2008)

Sumatran (Pongo abelii) and Bornean (P. pygmaeus Linnaeus, 1760) orangutans are now considered to be two distinct species, comprising the genus Pongo. Three subspecies are recognized for P. pygmaeus, but the Sumatran orangutan is a single taxonomic unit. The long-term viability of the entire genus is in question, but the Sumatran orangutan faces the more immediate threat of extinction and is listed as Critically Endangered on the IUCN Red List of Threatened Species.

The species is endemic to Sumatra, Indonesia. Truly wild populations are restricted to the remaining lowland forests of the two most northerly provinces of the island, Nanggroe Aceh Darussalam (NAD) and North Sumatra. A small reintroduced population is also currently being established in Jambi Province, further to the south.

About 6,600 wild individuals remain (based largely on nest density surveys and 2002 satellite imagery). They survive in just 10 fragmented habitat units stretching from the central regions of NAD, south to the Batang Toru River in North Sumatra, with a notable gap in their distribution immediately west of Lake Toba. The southernmost populations in North Sumatra could be genetically and culturally distinct from their more northern relatives due to isolation. The largest populations occur within Nanggroe Aceh Darussalam, where until 2005 a separatist conflict made monitoring and conservation work problematic. Recent surveys appear to have confirmed the absence of orangutans in the northernmost forests of NAD such that almost all orangutans in Aceh can be found within what is known as the Leuser Ecosystem.

The Leuser Ecosystem is a 26,000 km² conservation area established by presidential decree that encompasses the smaller Gunung Leuser National Park (10,950 km²; itself part of the Sumatran Rainforest World Heritage Site) and the 1,025 km² Singkil Swamps Wildlife Reserve. About 5,800 orangutans are considered to remain in the Leuser Ecosystem. The Leuser Ecosystem, and the smaller National Park and Wildlife Reserve within it, forms the only conservation area where viable wild populations of the Sumatran orangutan, Sumatran tiger, Sumatran rhinoceros and Sumatran elephant, each of which is endangered in itself, still occur side by side. The National Park, however, mostly comprises high mountains, and as the orangutan is predominantly a lowland species, rarely being found above 1,000 m above sea level, the majority of orangutans are found within the larger Leuser Ecosystem but outside of the National Park itself. For example, the Ecosystem harbors c.88% of the remaining 6,600 Sumatran orangutans whilst only 30% are found within the National Park and 23% within the Singkil Swamps Wildlife Reserve.

Throughout its range, the primary threat to the Sumatran orangutan is habitat conversion and fragmentation. Logging, both legal and illegal, often leads to total conversion of forests for agriculture or oil palm plantations. Roads are also a constant threat, since they further fragment already declining populations and also give access for additional logging and encroachment. Although precise rates of forest loss are difficult to determine, primary lowland forests in Sumatra have been devastated over the last 30 years. One study of forest cover concludes 301,420 ha, or 13% of the original 2,284,771 ha of forests, were lost in North Sumatra Province alone between 1990 and 2000 (Gaveau et al. 2007). A second analysis, more focused on orangutan habitat in Sumatra concluded that habitat supporting around 1,000 orangutans was being lost each year in the Leuser Ecosystem alone during the late 1990s (van Schaik et al. 2001). This was largely due to legal logging concessions and conversion of lowland forests to oil palm estates, but also to illegal logging and encroachment in some places.

Fortunately, the rate of habitat loss decreased markedly in many areas during the Aceh civil conflict, as even loggers did not consider it safe to work in the forests. In fact, Gaveau et al. (2007) found that satellite data indicated that the rate of loss was five times faster in Aceh between 1990 and 2000 (294 km² or 0.75% per year) than it was between 2000 and 2006 (58 km² or 0.15% per year). Orangutan populations have nevertheless plummeted in those regions that have still been affected by logging. Even small-scale selective logging can reduce local orangutan densities by as much as 60% in Sumatra (Rao and van Schaik 1997).

Encroachment and conversion, especially by settlers fleeing the conflict in NAD and migrants from Nias Island, also accelerated habitat loss in some parts. After the 2004 tsunami many people moved from coastal areas, and the subsequent increase in demand for timber still poses a significant threat. Several new roads (part of a project known as Ladia Galaska) have also begun further fragmenting remaining orangutan habitat. Proposed new roads are a particular concern in the Singkil Swamps Wildlife Reserve, especially as Sumatra's peat swamp forests support the highest densities of orangutans in the world. This is expected to become a major problem in coming years as illegal loggers and settlers gradually move in and open up new agricultural land. Throughout their range, orangutans are sometimes killed as pests at the forest edge as they raid agricultural crops (particularly highly prized fruits such as durian), and in parts of North Sumatra Province they are occasionally still hunted for food. A small yet still significant trade in young Sumatran orangutans as pets also persists.

Key conservation interventions rely heavily on a dramatic and rapid improvement in enforcement of wildlife and forest laws and far greater consideration for environmental issues in spatial planning decisions. Implementing patrols, improving law enforcement (especially the number and frequency of cases actually prosecuted), stopping illegal logging, halting legal logging and forest conversion to plantations, promoting forest restoration, halting road construction, addressing human-orangutan conflict, and providing connectivity in the landscape to allow for genetic exchange are all seen as prerequisites for the species' survival. There is some cause for optimism, however. The Indonesian government has developed a National Strategy and Action Plan for Orangutan Conservation 2007–2017 (DitJen PHKA 2007) and the Government of NAD has also imposed a moratorium on all logging in the Province. Nevertheless, as with so many plans and laws, if not strictly followed and enforced, both could result in little or no change from business as usual. Indeed, if pre-civil conflict rates of habitat loss resume in NAD and the protected status of remaining habitat outside of the Leuser Ecosystem is not quickly enhanced, we could see a further 50% of Sumatran orangutans vanish within a decade. Effective long-term solutions to conserve northern Sumatra's remaining lowland primary forests are still urgently needed.

Ian Singleton, Jatna Supriatna & Serge A. Wich

Neotropical Region

Variegated or Brown Spider Monkey

Ateles hybridus I. Geoffroy, 1829

Colombia, Venezuela

(2004, 2006, 2008)

There are two recognized subspecies of the variegated or brown spider monkey. Ateles hybridus brunneus Gray, 1870 is restricted to Colombia, occurring between the lower Ríos Cauca and Magdalena in the Departments of Bolívar, Antioquia and Caldas. Ateles h. hybridus occurs east from the right bank of the Río Magdalena extending into western Venezuela. Both subspecies are Critically Endangered due to habitat loss, hunting and the pet trade.

The large size, slow reproductive rate (single offspring at 3–4 year intervals) and generally low population densities of spider monkeys make them especially vulnerable to hunting. Historically, A. hybridus has suffered from habitat destruction, and only 0.67% of the current remaining range of A. hybridus is protected; most has been converted to farms for agriculture and cattle.

Ateles h. brunneus has a small geographic range in a region where forest loss, degradation and fragmentation is widespread. Currently, the remaining populations are surrounded by human populations, compounding the already high level of threat. Only 9% of their potential range remains as continuous forest. This subspecies has been identified in different areas of the Antioquia department, such as: Segovia, Remedios, Maceo, Yondó, Puerto Berrio, and Zaragoza. However, the habitat destruction and hunting pressure over this species has provoked possible local extinctions. Between 2007 and 2008, surveys in this Department yielded some possible areas where this species no longer exists (for example, Vereda El Brazil, Corregimiento La Sierra). Surveys have been conducted to determine the density of this subspecies in the municipality of Maceo. In 2006 one group of eight individuals were found in this area, and by 2008 just four individuals were spotted in the same area, after five months of surveys. A refuge remains, however, in the Serranía San Lucas in southern Bolívar, and in some parts of Nechí, identified as important areas for the establishment of national parks. A protected area is highly necessary for this subspecies that also would include two other threatened endemic primates, the white-footed tamarin, Saguinus leucopus, and the woolly monkey, Lagothrix lugens.

Ateles h. hybridus is extremely endangered due to habitat destruction in both Colombia and Venezuela. The lowland forest of the state of Zulia and the piedmont of the Perijá Mountains are heavily destroyed from expansionist cattle-ranching activities. Within the Perijá Mountains only 30% of the forest is relatively well preserved and protected. The rest is affected by rapid human expansion and land clearing, poor protection and increasing fragmentation, putting potential corridors at risk in most of its extent. Also in the Perijá Mountains, brown spider monkeys seem to be favorite game. In central Venezuela, some areas that had populations in 2001 were resurveyed in 2007 without successful sightings; most of the areas were already covered by secondary vegetation. The lowland forest from the eastern part of the Andean Mountains, San Camilo and Ticoporo, are under severe logging pressure.

Ateles hybridus can be found in at least six zoos in Colombia, presenting problems of surplus animals and consanguinity. This species is suffering also from the pet trade; about 20 confiscated individuals are currently in residence in four rescue centers and need to be relocated. There is an urgent need for surveys to establish areas with populations of this species and to propose conservation measures. An ex situ breeding program is also necessary to maintain healthy and viable captive populations.

Erwin Palacios, Alba Lucia Morales-Jiménez & Bernardo Urbani

Peruvian Yellow-tailed Woolly Monkey

Oreonax flavicauda (Humboldt, 1812)

Peru

(2000, 2006, 2008)

The taxonomy of the yellow-tailed woolly monkey has been a matter of some discussion. First described as Simia flavicauda by Humboldt in 1812, it was again described by Thomas (1927a) as Lagothrix (Oreonax) hendeii a century later. Later in the same year, after receiving a new juvenile specimen, Thomas (1927b) elevated the subgenus Oreonax to full generic status. In his revision of the woolly monkeys, Fooden (1963) found that S. flavicauda and O. hendeii were actually the same species and very closed related to Lagothrix, and he thus named it Lagothrix flavicauda. Groves (2001) revised some available skulls and found it more closely related to Ateles, and consequently separated flavicauda from Lagothrix, and revived Thomas' old genus Oreonax. Most recently, Matthews and Rosenberger (2008a, 2008b) revised Groves' work and found evidence for a “misclassification because a heuristic measure of statistical support has been misconstrued as a biological and phylogenetic characteristic”, and therefore argued against the validity of Oreonax as a genus. A more comprehensive reassessment of the systematics of Lagothrix is still needed, using a wider set of characters and samples, both in morphology and molecular genetics.

The Peruvian yellow-tailed woolly monkey is endemic to Peru, and is found only in a small area in the Tropical Andes. Oreonax flavicauda is known to persist only in primary premontane, montane and cloud forest between 1,500 to 2,700 m above sea level (Leo Luna 1982; Butchart et al. 1995; DeLuycker 2007; Shanee et al. 2008). Historically, the distribution of the species may have included the regions of Amazonas, San Martín, Huánuco, Loreto and La Libertad, as predicted by the species distribution modeled by Pacheco et al. (2007). Now the species is restricted to scattered forests in only two regions—Amazonas and San Martín (Heymann and DeLuycker 2007; Shanee et al. 2008). There are no current estimates of remaining population numbers. Indiscriminate clear-cutting of primary cloud forest is the principal threat to this species, and its habitat has been largely deforested, resulting in a strongly fragmented landscape.

We estimated the extent of the historical distribution area of O. flavicauda, based on a model without taking into account current deforested areas and human settlements, to be 41,446 km². In 1981, it was estimated that the potential forested habitat was at least 11,240 km² and it was predicted that at least 1,600 km² would be deforested for agriculture by 1991 (Leo Luna 1984). With a modeled distribution using known localities and suitable habitat, we estimate the current potential distribution of O. flavicauda to be 7,690 km², a number that is rapidly diminishing due to a high rate of human immigration to the area, combined with unregulated land use. In addition, much or most of this forest is now highly fragmented or isolated from other tracts of forest. Oreonax flavicauda has likely declined drastically in numbers due to a major reduction in area of occupancy and a decrease in the quality of their habitat.

Very little is known about the ecology and behavior of the yellow-tailed woolly monkey. Results from studies in the early 1980s indicated that the sizes of its multi-male/multi-female groups range from 5 to 18 individuals. Oreonax flavicauda eats a variety of fruits, flowers, leaves, lichens, leaf bases of bromeliads, epiphyte roots and bulbs, and possibly insects (Leo Luna 1982; DeLuycker 2007). Surveys in the Amazonas region found groups ranging from 7 to 10 individuals (Cornejo et al. 2007), but DeLuycker (2007) reported an unusually large group (17–20 individuals) in an area relatively close to agricultural plots. The species appears to be very sensitive to habitat disturbance (Leo Luna 1987; DeLuycker 2007). Where the forest is disturbed by logging, O. flavicauda decreases its use of the area (Leo Luna 1984), often retreating further into high-altitude forests far away from human settlement, where it is able to use larger tracts of forest. In 1981, it was estimated that O. flavicauda occurred in low densities, from 0.25 to 1 group per km² (Leo Luna 1987). Recently, a survey conducted in a forest fragment provided an estimate of 1–2 groups per km² (Cornejo 2007). Based on the difficulty of locating groups of O. flavicauda during an intensive three-month survey, DeLuycker (2007) suspected this species to have large home ranges (as do other atelins), but Cornejo (2008) estimated the home range of a single group as only 69 ha.

The species is known to be present in the Río Abiseo National Park (PNRA) (2,745 km²), the Alto Mayo Protected Forest (BPAM) (1,820 km²), and the Reserved Zone Cordillera de Colán (ZRCC) (641 km²), all of which were established with assistance from the Asociación Peruana para la Conservación de la Naturaleza (APECO). Between 1996 and 2001, more than 6,000 ha of primary forest were cleared inside the BPAM (Peru, INRENA 2008). The forest of the BPAM is now considerably fragmented, a result of lack of enforcement and a substantial human population living in the protected forest itself. The “Reserved Zone” Cordillera de Colán (ZRCC) is finally being categorized as a National Sanctuary and a Community Reserve of Awajun Natives, after many years of being without a formal categorization and a management plan. BPAM and ZRCC also suffer from illegal selective logging—ZRCC has two operative mining concessions near its borders, and both areas have the constant threat of human unregulated migration. Oreonax flavicauda has been extirpated from all but the most distant and isolated forests on the eastern side of the Río Alto Mayo. Illegal hunting still occurs within and outside protected areas, and if monkeys are encountered, they are likely to be shot, because of their size, conspicuousness, and trustful behavior toward humans. The species' velvety, thick, long fur, its skin and skull, and yellow genital hair-tuft are sought after as trophy items, and make this species a target for hunters even when they do not hunt it for subsistence. Infants taken when their mothers are shot are sold in markets as pets. PNRA is the only governmental protected area that, because of its inaccessibility, is actually protecting the yellow-tailed woolly monkey. Unfortunately, PNRA is only protecting 852 km² of suitable habitat for the species (M. Leo Luna unpubl. data).

There is very little information on the biology and natural history of this species, resulting mainly from the difficulties imposed by the mountainous and precipitous terrain where it lives. A complete, range-wide survey of its cloud forest habitat is urgently needed to develop plans to protect the remaining populations of Oreonax flavicauda. These surveys should also include population genetic studies, to examine genetic variability and the viability of existing populations.

Currently, a number of institutions are investing efforts and resources in northeastern Peru's cloud forests. Some community-based conservation projects are underway (Ucumari, Apenheul, Neotropical Primate Conservation [Shanee et al. 2007, 2008] and the Museo de Historia Natural—UNMSM in Amazonas), protected area policies and management plans are being enforced (APECO and Deutsche Gesellschaft für Technische Zusammenarbeit—GTZ), private reserves are being established (Asociación Ecosistemas Andinos, Sociedad Peruana de Derecho Ambiental), and conservation education campaigns are being held (Yunkawasi). While these conservation efforts have already produced some positive results, they are not enough. The regions of Amazonas and San Martín have the highest rates of deforestation of Peru (Reategui and Martínez 2007)—the product of very deep social conflicts in the area, with illegal logging and illegal land traffic being the main problems.

Urgent conservation initiatives necessary for the yellow-tailed woolly monkey's survival should continue and include: increased protection within designated parks, reserves, and protected forests, which currently lack enforcement; the establishment of a contiguous area of protected forest, to create a biological corridor; control of illegal logging; purchase of land; the provision of alternative economic models for local communities living along buffer zones, in order to prevent further migration into the primary cloud forests; and the implementation of a strong conservation education plan.

Fanny M. Cornejo, Anneke M. DeLuycker, Heidi Quintana, Victor Pacheco & Eckhard W. Heymann