This study evaluated the macro-invertebrate fauna in water bodies of southern Nigeria spanning the rainforest and derived savanna ecozones. The benthic macro-invertebrate fauna of Edo Ecozone comprises 55 taxa, belonging to 13 major groups. The abundance of major taxonomic groups varied considerably among the surveyed aquatic ecosystems. Chironomidae (Diptera) were well represented and dominant in 11 of the 20 water bodies surveyed. Most rare and restricted species were gastropods (Mollusca), one such species, Mutela cf. dibia, being endemic to the catchment. The overall abundance was maximal (97) at Okomu River in the lowland forest and minimal (5) at Avielle River in derived savanna, respectively. The human impact on macro-invertebrate biodiversity is documented, including changes in benthic fauna distribution patterns.

Trends in the distribution, population dynamics and reproductive biology of the estuarine cirolanid isopod, Cirolana fluviatilis, were investigated over a 12-month period in the warm–temperate Gamtoos River Estuary, by means of baited traps. Tolerance of adult isopods to combinations of salinity and temperature, and sediment preference, were investigated in the laboratory. Isopods were captured in highest numbers in the lower to middle reaches of the estuary, which appears to be related to a preference by C. fluviatilis for sediment with high mud content. Size-frequency distributions tended to be unimodal, becoming slightly bimodal only after manca release, which occurred predominantly during the warm summer months (December–March). Female C. fluviatilis reached sexual maturity at a length of about 6.0 mm, and males at about 5.2 mm. Fecundity was positively correlated to female body length. Brooding females remained inactive, leading to temporal variations in the male to female ratio.

The Knysna seahorse, Hippocampus capensis, is an endangered teleost confined to three South African estuaries. Its abundance within these systems is low and distributions are patchy. Consequently, monitoring population sizes is labour-intensive. The aim of this study was to establish if Knynsa seahorses are associated with specific regions within the estuaries, on which conservation efforts could concentrate. The relationship of Knysna seahorses with aquatic vegetation was analysed in the Knysna Estuary (the largest of the three estuarine systems inhabited by H. capensis) to determine whether this species shows a preference for a particular plant species, vegetation density or vegetation height. Seahorses were associated with five dominant aquatic plants: Zostera capensis, Caulerpa filiformis, Codium extricatum, Halophila ovalis and Ruppia cirrhosa. Together, these comprised 96% of the submerged objects with which seahorses were associated. The relative abundance of plant species changed along the estuary, but seahorses were present throughout the system, except at the estuary mouth, which was characterized by low plant densities and strong currents. No significant difference was found between the proportion of plant species present in a particular region of the estuary and the proportion of plants that seahorses used as holdfasts. However, when Z. capensis and C. filiformis were present at the same sites, adult seahorses preferred C. filiformis as holdfast. Adult seahorse density (individuals/m²) was significantly correlated with percentage vegetation cover and with holdfast length, but juvenile seahorse density was not. Nonetheless, significantly more adult and juvenile seahorses were found at sites characterized by high vegetation cover (>75%) than at sites with lower cover. Our results indicate that although there is some evidence that Knynsa seahorses prefer certain plant species over others, they are likely to be encountered anywhere in the estuary where aquatic plants are present. Conservation efforts in the Knysna Estuary should thus concentrate on such vegetated areas, which comprise approximately 11% of the total submerged surface area.

Pastoralists on rangelands adjacent to the Baviaanskloof Provincial Nature Reserve, Eastern Cape, report stock losses through predation by leopards (Panthera pardus). This leads, in certain cases, to persecution of the leopards. This study attempted to quantify livestock depredation by leopards by comparing leopard diet within and outside the reserve. Leopard scats from both areas were analysed for prey items. A total of 18 prey taxa was identified, including small to medium-sized ungulates, rodents, birds and a felid. The mountain reedbuck was the most frequently utilized prey, followed by vlei rat, bushbuck, rock hyrax and grysbok. Baboons, although abundant throughout the study area, were not utilized by these leopards. There was a significant difference in the frequency of prey items between the reserve and the rangeland samples in terms of the relative contribution of the prey taxa. Medium-sized and small ungulates were heavily utilized in the reserve, whilst the diet in rangelands was composed largely of small mammals (including small ungulates). Only two scats contained the remains of domestic animals, indicating that <5% of the diet comprised this prey category, and suggesting that leopards in the study area do not preferentially prey on livestock.

We examined 170 museum specimens of the southern African gekkonid lizard Homopholis wahlbergii, to quantify sexual dimorphism, male and female reproductive cycles and diet. The largest male and female we recorded were 116 and 119 mm snout–vent length (SVL) respectively. We compared SVL, tail length, head length, head width and eye diameter and found no evidence of sexual dimorphism in any of these characters. The smallest female with thickened muscular oviducts and follicles, indicating sexual maturity, was 59 mm SVL, but the smallest female we found with fully developed eggs was 85 mm SVL. Virtually all females larger than 59 mm appeared to be in some stage of reproduction, suggesting that females reproduce every year once they reach sexual maturity. Egg size ranged from 17–19 mm long. Egg size was not correlated with maternal SVL. We found adult females with ready-to-lay eggs during the warmer months of the year, but not during winter and spring. The smallest sexually mature male was 72 mm SVL. Virtually all males larger than this size displayed at least semi-turgid testes and most adult male testes were at least semi-turgid for much of the year. The only significant decrease in testicular activity was in mid-winter (June–August), thus, spermatogenesis is closely tied to female follicular development and ovulation. Velvet geckos are largely insectivorous (92%) and feed on a broad spectrum of prey. Their diet was dominated both numerically (34%) and volumetrically (22%) by beetles. Lepidoptera were the next most important prey category, suggesting that they exploit both terrestrial and flying invertebrates. They are unusual among lizards because they feed on millipedes. Males and females had very similar diets which may be explained by their lack of sexual dimorphism, although females tended to eat a greater volume of prey. Interestingly, less than half (37%) of the lizards examined contained prey items, suggesting that most individuals were not in positive energy balance. We also found evidence of prey size selection as a function of gape size, such that larger geckos took advantage of larger prey items.

Metriaclima lanisticola, a native cichlid of Lake Malawi, was studied under laboratory conditions to evaluate its possible role as a predator of snails (Bulinus spp.). Bulinus globosus, B. nyassanus and B. tropicus were used as prey. B. globosus and B. nyassanus are intermediate hosts of human schistosomes in Lake Malawi. M. lanisticola orally shelled snails of all three species. Even when small snail sizes were offered, the fish shelled them. This suggests that M. lanisticola is entirely an oral sheller. Opercula of Melanoides species were commonly found in the stomach contents of wild-caught M. lanisticola, while whole snail shells or shell fragments were never observed, further suggesting that the fish is an oral sheller. M. lanisticola consumed more B. nyassanus in aquaria without substratum than in aquaria with a sandy substratum and apparently the fish is dependent on visual perception for prey detection.

The incidence of torpor during summer and winter in response to cold exposure in Mops condylurus was studied in a subtropical environment. Body temperature changes under natural roosting conditions during winter and summer were monitored using bats fitted with temperature-sensitive radio transmitters. Rectal temperatures of free-roosting bats were also measured during winter. During summer, the effect of clustering on the incidence of torpor under different climatic conditions was investigated. Mops condylurus were thermolabile and displayed daily bouts of torpor during winter and summer, with body temperatures closely conforming to ambient temperatures. Body temperatures as low as 12.0°C were recorded during winter. Regression analysis showed a positive correlation between body and ambient temperatures in winter and summer. There was no difference in the incidence of torpor between single and clustering bats, although single bats maintained slightly higher body temperatures. Results indicate that M. condylurus maintained an optimally small T_b–T_a differential by readily becoming torpid under roosting conditions, thereby minimizing energy expenditure.

In eastern Africa, populations of the tree snail Sitala jenynsi are monomorphic, dimorphic or trimorphic for the width of the upper brown band on their shells. We measured the variation in the width of this band in several populations and analysed it using two mutually verifiable methods: arithmetical probability paper and regressions of log-transformed shell metrics. The demarcations of the three morphs in areas of spatial overlap between the band-width states have been defined. We recognized existence of type I narrow-banding which associates monomorphism, and type II narrow-banding, medium banding and wide-banding forms which associate polymorphism. We have also quantified the variation in three other characters, two of which are also polymorphic: a lower pigmented band and an upper unpigmented ‘ghost band’. The evolutionary implications of the findings are discussed. Continued use of varietal names to describe the banding polymorphism of S. jenynsi is recommended, in preference to the multidimensional colour pattern notation commonly applied to gastropods.

Basking is a behaviour frequently observed in the rock hyrax (Procavia capensis) during winter that supposedly plays a significant role in rewarming from nocturnal hypothermia. This behaviour, together with changes in body temperature and changes in black bulb temperatures (T_bb) were investigated in the natural environment. In this study, rock hyraxes did not reduce their body temperature substantially overnight and thus basking was not used for rewarming but rather to maintain constant body temperatures under low ambient conditions. Frequency of basking changed throughout the day as T_bb increased and decreased. Different basking postures (hunched or flat), orientations to the sun and basking bout lengths were modified depending on T_bb experienced. There was no difference in body temperature between the two basking postures at any T_bb. It appears that rock hyraxes did not use basking behaviour as a way of warming up after night-time but used it during the day as a diurnal energy conserving mechanism.

We studied waterfowl abundance and diversity in relation to season (wet vs dry), wetland characteristics (vegetation and morphometrics) and land-use in a semi-arid agricultural region of South Africa to determine how waterfowl respond to various wetland characteristics, particularly those of permanent agricultural ponds. Wetlands were visited during the wet (n = 215) and dry (n = 178) seasons of 1997 and species' abundances, and wetland and upland characteristics were recorded. Canonical correspondence analyses and multiple regressions determined which wetland and upland characteristics were most strongly associated with waterfowl density and species richness for both the wet and dry season. Overall, diving ducks were not abundant in the wet season, and were rare to absent in the dry season. Divers only responded positively to the characteristics of natural wetlands, including greater surface area, percent coverage of emergent vegetation, and high (ungrazed) shoreline vegetation. Of six species of dabbling ducks present during the wet season, occurrence of three co-varied with wetland and upland characteristics associated with agriculture, namely permanent water, and agricultural grains in the dry season. Being largely grazers, geese responded positively to the higher proportions of bare shoreline, characteristically surrounding agricultural ponds. Because only a few species associated with artificial waterbodies, natural wetlands should be conserved to protect waterfowl diversity in semi-arid South Africa.

In lizards, pheromonal cues are important for mate recognition and are expected to diverge during the speciation process. We tested for divergence in pheromonal mate and species recognition between male flat lizards (Platysaurus broadleyi) belonging to the same population, a different population, and a sister species. Males were given a choice between two refuges, an odourless control and one of the following: a conspecific female from the same population (sympatric), a conspecific female from a distant population (allopatric), and a female from their sister species (heterospecific), P. capensis. Males chose refuges treated with the scent of a heterospecific over an odourless control refuge but showed no preference for refuges that were scented with female conspecific (allopatric or sympatric) cues over the control. These results were consistent in the breeding and non-breeding seasons. In a second experiment males were offered a choice of female scents between sympatric and allopatric conspecifics; an allopatric conspecific and a heterospecific; and a sympatric conspecific and a heterospecific. Males showed a trend of preferring heterospecific over conspecific refuges and allopatric over sympatric conspecific-scented refuges, but these results were not significant at alpha <0.05. Contrary to our original expectations, these experiments do not provide any evidence for a pheromonal pre-mating isolation mechanism within this species complex. However, our results suggest a preference for novel female scents by males, consistent with selection for genetic diversity.

Assessing the risk of extinction to species forms an essential part of regional conservation initiatives that facilitate the allocation of limited resources for conservation. The present study conducted conservation priority assessments for 221 South African terrestrial mammal species using existing data sources. These data sources included regional IUCN Red List assessments, regional geographic distributions, relative endemism, taxonomic distinctiveness, relative body mass and human density. These components were in turn subjected to two quantitative conservation priority assessment techniques in an attempt to determine regional conservation priorities for South African terrestrial mammals. The top 22 mammal species (i.e. the top 10% of assessed species) identified by both regional conservation priority assessment techniques to be of conservation priority, consistently identified 13 South African terrestrial mammal species to be of high conservation priority. Seven of the 13 species were from the order Afrosoricida, two species from the order Eulipotyphla, with one species each from the orders Chiroptera, Lagomorpha, Pholidota, and Rodentia. More importantly, 12 of the 13 mammal species were also listed as threatened in the 2004 Red Data Book of South African Mammals. These results suggest that the two conservation priority assessment techniques used in the present study may represent a practical and quantitative method for determining regional conservation priorities, and include measures that represent vulnerability, conservation value, and threat.

The snake Psammophis schokari has a widespread distribution across North Africa, and in Morocco/Western Sahara is represented by three different morphotypes: striped, unicoloured and the Western-Sahara morph. ND4 mitochondrial DNA sequences from 28 specimens comprising 20 P. shokari, two P. aegyptius, one P. elegans, two P. sibilans, one P. condanarus and two outgroups were analysed. Within P. schokari we identified four genetic lineages (Morocco/Western Sahara, Mauritania, Algeria and Israel) with a genetic divergence ranging from 4–5%, less than that typically found between different species. Surprisingly, Moroccan/Western Sahara and Algerian lineages are the most divergent ones. This geographic substructuring may be due to severe climate changes in the Sahara desert between the Miocene and Pleistocene associated with expansion/contraction phases of this desert. Psammophis aegyptius is the sister-taxon of Psammophis schokari with a high level of genetic divergence between them (10.7%) supporting the recognition of P. aegyptius as a distinct species. The three Moroccan/Western Sahara colour morphotypes form one genetic lineage, indicating that colour pattern does not reflect a different phylogenetic history, and is probably an ecological adaptation to the local environment.

The aquatic oxygen consumption of the estuarine brachyuran crab, Cyclograpsus punctatus, was investigated after a 24-hour acclimation period at different temperature (12.5, 20, 30°C) and salinity (9, 17.5, 35, and 44‰) combinations. Salinity had no significant effect on oxygen consumption at 12.5 and 20°C in both large and small crabs. At 30°C and 44‰, however, the rate of oxygen consumption declined in large crabs (from 0.233 to 0.176 mg O₂ g wwt/h) and increased in small crabs (0.300 to 0.469 mg O₂ g wwt/h). There was also a significant increase in the oxygen consumption (0.300 to 0.536 mg O₂ g wwt/h) of small crabs at the high temperature/low salinity combination. Temperature had a significant effect on the rate of oxygen consumption at all salinities, with Q₁₀ values ranging from 1.16 to 2.85. In all cases the mass-specific oxygen consumption rate of small crabs was higher than that of large crabs. The results suggest that the confinement of this species to the lower reaches of estuaries may, in part, be due to physiological constraints on juveniles and small individuals.

The breeding of frogs in four ponds near Harare, Zimbabwe, was investigated during a wet rainy season (2000/01) and a dry one (2001/02). During 2000/01 eight and nine species bred in two ponds in abandoned gravel pits that never contained fish, but only four species bred in these in 2001/02 and the relative abundance was reduced by about 50%. Pond 3 was a small dam that filled after the rains and was invaded by fish once it overflowed. Five species bred in it in 2000/01, but breeding activity was curtailed once it was invaded by catfish, Clarias gariepinus, some of which were found with frog remains in their stomachs. The pond did not overflow in the following season, and was therefore not invaded by fish; although only four species bred in it their relative abundance was considerably higher. Pond 4 was a permanent pond that always contained fish. Only three species bred in it and the relative abundance of tadpoles was always low. Species belonging to the Ranidae seemed to be most severely affected by drought and this may explain the absence of some species, such as the African bullfrog, Pyxicephalus adspersus, that was once abundant around Harare.

Laboratory studies have resulted in classification of the marbled African lungfish, Protopterus aethiopicus, as an obligate air-breather. However, there have been no investigations of the extent of dependence on aerial respiration by this species in the wild. We used radio telemetry to obtain quantitative information on the surfacing frequency of lungfish in Lake Baringo. The results showed radio-tagged lungfish came to the surface during the period immediately following their release but that aerial respiration later ceased, indicating that the fish were able to meet their metabolic oxygen requirements solely through aquatic respiration. These results suggest that under certain conditions lungfish in the wild may not be obligate air breathers and that the use of aerial respiration may be a function of ecological as well as physiological factors.

One way to avoid potential predators is to be sensitive to odour cues, particularly those in faeces and urine, left by predators. This sensitivity has been demonstrated in many solitary, nocturnal, small mammals which may fall victim to ambush predators. We tested the response of Cape ground squirrels, a diurnal, group-living small mammal, to the presence of predator (black-backed jackal) faeces and non-predator (black wildebeest) dung in baited traps, and also predator faeces and non-predator dung outside their burrows. The squirrels showed a significantly higher avoidance of traps scented with predator faeces than both control and non-predator dung-scented traps. They also took significantly longer to emerge from burrows that had predator faeces outside compared with control burrows and burrows with non-predator dung outside and showed a trend for higher vigilance once they emerged from burrows with predator faeces outside. We argue that as diurnal group-living reduces a reliance on olfactory cues, this species is more likely to rely on visual cues and the vigilance of other individuals than nocturnal solitary species that have been the focus of most studies up till now. As a result, squirrels very quickly return to normal behaviour after exposure to a predator cue. Level of sociality is likely to influence responses to olfactory cues of predators and should be the focus of further studies.

The tadpole of Amietia wittei (Anura: Pyxicephalidae) is described from the highlands of Kenya. It is distinguished from the tadpoles of Amietia ruwenzoriensis, and A. angolensis, in the region by the numbers of labial tooth rows.