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A 2-year study was conducted on the forest cane turtle, Vijayachelys silvatica, in Chalakudy District, Kerala, South India. This is a poorly known species, endemic to the Western Ghats of Southern India. The aims of the study were to ascertain morphometrics, sex ratios, and reproductive data in the field. Female Vijayachelys were more massive than males and significantly larger in all the characters examined, except for straight-line carapace length. The sex ratio among adult individuals was 47 males to 36 females (1.31∶1), which did not differ significantly from 1∶1. The greatest number of turtles was found in October and the fewest in May. Mating was observed in the months of June, September, and November and oviposition in January and February. Clutch size was 2 eggs in most cases. Turtles were observed to feed on snails, mushrooms, centipedes, and beetles living in the molding leaf litter and humus. Almost all turtles had algae on their shells.
Kurt A. Buhlmann, Thomas S. B. Akre, John B. Iverson, Deno Karapatakis, Russell A. Mittermeier, Arthur Georges, Anders G. J. Rhodin, Peter Paul van Dijk, J. Whitfield Gibbons
There are currently ca. 317 recognized species of turtles and tortoises in the world. Of those that have been assessed on the IUCN Red List, 63% are considered threatened, and 10% are critically endangered, with ca. 42% of all known turtle species threatened. Without directed strategic conservation planning, a significant portion of turtle diversity could be lost over the next century. Toward that conservation effort, we compiled museum and literature occurrence records for all of the world's tortoises and freshwater turtle species to determine their distributions and identify priority regions for conservation. We constructed projected range maps for each species by selecting geographic information system–defined hydrologic unit compartments (HUCs) with verified locality points, and then added HUCs that connected known point localities in the same watershed or physiographic region and that had similar habitats and elevations as the verified HUCs. We analyzed a total of 305 turtle species and assigned each to 1 of 7 geographic regions of the world. Patterns of global turtle species distributions were determined and regional areas of turtle species richness identified. In only 2 areas of the world did as many as 18 or 19 species occur together in individual HUCs. We then compared species distributions with existing global conservation strategies (GCSs) and established biodiversity priority areas. Presence of a species in a GCS was defined as ≥ 5% its range. Of the 34 biodiversity hotspots, 28 collectively contain the projected ranges of 192 turtle species, with 74 endemic; the 5 high-biodiversity wilderness areas contain 72 species, with 17 endemic; and 16 other wilderness areas contain 52 species, with 1 endemic. However, 116 turtle species have either < 50% of their ranges in existing GCSs (57 species) or do not occur in them at all (59 species, 19.3%), thus potentially leaving many tortoises and freshwater turtles without any regional GCS. For each of these 116 species we identify a priority Ecoregion for further conservation consideration, and we identify 3 new global Turtle Priority Areas for conservation based on aggregated Ecoregions. These are the Southeastern United States, Lower Gangetic Plain, and Coastal Australia Turtle Priority Areas.
This paper provides the first overview of sea turtles in Guinea-Bissau, presents data on their ecology, and analyzes threats and conservation initiatives. The green turtle (Chelonia mydas) is by far the most widespread and abundant of the 5 species that nest in Guinea-Bissau. Between ca. 7000 and 29,000 green turtle nests are laid per year at the globally important site of Poilão Island, with a few hundred more on surrounding islands. There is a marked interspecific variability in nesting seasonality, with green and hawksbill (Eretmochelys imbricata) turtles nesting mostly during the rainy season and olive ridley (Lepidochelys olivacea) and leatherback turtles (Dermochelys coriacea) during the dry season. Informal interviews all over the coastal zone suggest that sea turtle populations have markedly declined within living memory. Main threats are poaching of eggs and of nesting females and the incidental capture in fishing gear. Amongst the major achievements of sea turtle conservation efforts are that all species are protected by law, the most important nesting beaches have been included in the protected area network, and significant progress has been made in removing the presence of settlements of foreign fishermen from the areas near the turtle concentrations where accidental captures used to occur. On the down side, it should be pointed out that protection in the national parks is insufficient. The main problem seems to be the weak enforcement of park and national rules by park authorities, which creates a feeling of relative impunity in park residents and visiting fishermen.
During an accreditation review of the Shark Reef Aquarium at the Mandalay Bay Hotel in Las Vegas, Nevada, AZA (Association of Zoos and Aquariums) reviewers expressed concern about the possible effects of low light intensity and absence of ultraviolet light on serum 25-hydroxyvitamin D levels in our green turtles (Chelonia mydas). In an effort to address this concern, blood samples from the aquarium's 3 resident green turtles were periodically analyzed over a 5-year period. Serum 25-hydroxyvitamin D level in a green turtle living at a second indoor facility for 432 months was also analyzed. Two of 4 turtles housed at a third facility were moved from an outdoor to an indoor habitat, and serum 25-hydroxyvitamin D level of all 4 turtles was measured over a 2-year period. In this limited population, serum 25-hydroxyvitamin D levels began to decline about 4–5 months following indoor confinement and continued to decline for 6–8 years. Turtles in the outdoor facility had vitamin D3 blood serum concentrations of 60–70 nmol/L. After 6–8 years of confinement indoors, blood serum concentrations of vitamin D3 declined to 5–15 nmol/L. Although clinical symptoms of low serum 25-hydroxyvitamin D levels were not detected during regular veterinary examination of this limited study population, further research is needed to elucidate the long-term effects of restricted ultraviolet exposure or low dietary intake of vitamin D3 in green turtles. Blood serum concentration of vitamin D3 in wild turtles has apparently not been reported.
During terrestrial nesting forays, north-temperate freshwater turtles may experience a range of environmental temperatures that could cause overheating or constrain movement if temperatures are too high or low. Yet, we have very little understanding of how body temperature (Tb) varies in freshwater turtles during various nesting foray activities. We studied Tb variation in Chrysemys picta marginata from a small marsh in northern Michigan, 2003–2004. Three individuals left the marsh, nested, and returned to the marsh in a single day; whereas, 5 others remained on land for up to 3 days, mostly immobile under leaf litter. While on land, Tb of turtles and air temperature (Ta) showed parallel, diel oscillations. Mean Tb of mobile turtles exceeded prevailing Ta values but was similar to Tb recorded for those same individuals while aquatic 1 week before and after the nesting foray. Therefore, active nesting turtles on forays may have maintained suitable Tb values by use of sun or shade. During the nesting process, Tb decreased from 23.5°C to 20.0°C. Turtles that entered terrestrial refugia after evening nesting had Tb values similar to those while mobile, often at times when the evening sky illuminated the nesting areas. Therefore, low light levels, which could limit navigation, and Tb values, which could impede movements, did not directly cause turtles to seek terrestrial refugia after nesting. Instead, we suggest that impending low environmental temperatures, waning light levels that would eventually impair navigation abilities, and, ultimately, the risk of predation while returning to the marsh caused turtles to seek terrestrial refugia.
KEYWORDS: Reptilia, Testudines, Testudinidae, Stigmochelys pardalis babcocki, tortoise, rehabilitation, release into the wild, postrelease monitoring, South Africa
Babcock's leopard tortoises (Stigmochelys pardalis babcocki) are taken to rehabilitation centers in KwaZulu-Natal province, South Africa, because they are either escaped, unwanted, or confiscated pets, or else are confiscated from persons who acquire them illegally from the wild. South African rehabilitation centers are reluctant to euthanize tortoises, and there are few tortoise sanctuaries. Consequently, the local conservation authority, Ezemvelo KwaZulu-Natal Wildlife, developed a release protocol based on International Union for Conservation of Nature and Natural Resources guidelines, to facilitate the release of rehabilitated S. p. babcocki into the wild. The present study was done to determine whether rehabilitated animals could be successfully released into the wild, judged by whether individuals were able to survive in the wild. Seventeen apparently healthy individuals, with longer than 100-mm carapace length, that had been in captivity for more than 2 months in a large rehabilitation center were released into the wild. These rehabilitated animals, with attached radiotelemeters, were hard-released at 2 different sites within the historical range of the species and were monitored over a year. One of the tortoises was returned to captivity because of disease, 3 were killed intentionally or accidentally by humans, one died probably due to being turned over by another animal, 3 others died from a combination of disease, starvation and/or dehydration, and the fate of 6 was unknown. Because only 2 animals survived 13 months after release at one of the sites and only one was known to have survived 25 months after release at the other site, rehabilitated S. p. babcocki were not successfully released into the wild. However, recommendations to improve the probability of success of future releases of rehabilitated S. p. babcocki into the wild are provided.
We studied the nesting behavior of the pig-nosed turtle, Carettochelys insculpta, in northern Australia. We used remote camera systems and focal observations to test the hypothesis that the nesting behavior in C. insculpta is similar to that of its closest relatives, the softshell turtles (Trionychidae). Carettochelys nested at night, in contrast to diurnal nesting in the majority of softshell turtles. Observations of groups of turtles in the water prior to nesting indicated gregarious or social behavior. On average, gravid turtles emerged around 6 times onto 1–2 beaches spanning 2 nights. Turtles nested at around 2100 ± 3 h, when sand temperatures at nest depth were near their maxima. Minimum air and water temperatures during nesting were 17.5°C and 24.6°C, respectively. Nesting turtles spent an average of 27 min on a beach, similar to softshell turtles but shorter than reported for most other turtle species. Relatively short nesting duration in these species may be caused by the ease in excavating a chamber in sand and the close proximity of nesting areas to water. Overall, the nesting sequence reflected the conservative nesting behavior in turtles, was similar to that of softshells, but differed in subtle ways. Empty nest chambers, commonly referred to in the literature as “test holes”, were sometimes the result of abandonment resulting from incidental contact between turtles searching for a nest site.
Peter B. Richardson, Michael W. Bruford, Marta C. Calosso, Lisa M. Campbell, Wesley Clerveaux, Angela Formia, Brendan J. Godley, Aaron C. Henderson, Kate McClellan, Steven Newman, Kristene Parsons, Martin Pepper, Susan Ranger, Jennifer J. Silver, Lorna Slade, Annette C. Broderick
This study reviews the status of marine turtles in the Turks and Caicos Islands (TCI) using data gathered during a multidisciplinary study involving field surveys, questionnaire-based interviews, and molecular genetics between 2002 and 2006. Large aggregations of foraging turtles in the archipelago's waters are dominated by juvenile green (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata), with provisional mixed-stock analysis of these species suggesting that the aggregations originate predominantly from larger and relatively proximate source rookeries in the Wider Caribbean region. This study also suggests that the islands host remnant nesting populations of turtles, with hawksbill turtle nests recorded more frequently than green and loggerhead turtle (Caretta caretta) nests. The TCI islanders retain a culture of turtle use, with the current regulated and legitimate harvest likely to be one of the largest among the Caribbean Islands. This study suggests that historic and current harvest of turtles and their eggs in the TCI may have contributed to the apparent decline in the country's nesting populations. In order to address this conservation concern, changes to the regulation and management of the TCI's turtle fishery are necessary, but further research is needed to inform these changes.
Turtle researchers often use depredated nest surveys as an index of the total number of turtle nests laid. However, it can be difficult to determine whether an empty nest hole indicates a depredated nest or not. In such cases the presence of depredated egg shells clearly indicates that a nest was present; similarly, absence of eggshells may be interpreted to mean that no nest was present. We measured the amount of calcium in raccoon (Procyon lotor) scats at depredated nests of diamondback terrapins (Malaclemys terrapin) at Jamaica Bay Wildlife Refuge, New York, and found that during the first half of the nesting season, raccoons ingested egg contents without their shells, but during the second half of the season they ate whole eggs with shells. Researchers who use the presence of egg shells during depredated nest surveys should be aware that their counts may be affected by this change in predation behavior by raccoons.
A fragmentary radius of Hesperotestudo bermudae from an underwater cave deposit in Bermuda is only the second known specimen of the species. The exact provenance and age of the specimen have been lost, but the record provides additional evidence that there was a population of endemic tortoises on Bermuda in the Pleistocene.
Two separate populations of threatened gopher tortoises (Gopherus polyphemus) in Florida were found to carry Salmonella spp. during relocation efforts from Orange and St. Johns Counties to Walton County. The potentially zoonotic bacteria were detected using cloacal swabs for culture and PCR analysis. Although there was a difference in the amount of perceived clinical stress undergone in each group, the percentage of tortoises shedding Salmonella was not statistically significant between the cohorts (9% and 11%). All isolates underwent antibiotic sensitivity testing and were susceptible to 10 antibiotic compounds.
Skeletochronological analysis was used to compare stained and unstained cross sections of humeri from Kemp's ridley (Lepidochelys kempii) and loggerhead (Caretta caretta) sea turtles to determine if the 2 histological techniques yielded an equal number of visible lines of arrested growth (LAGs). Stained sections viewed at high magnification under a compound microscope revealed the presence of closely spaced and splitting LAGs, resulting in a greater number of individual LAG counts for these sections when compared to unstained and stained sections viewed at a lower magnification under a dissecting microscope. Prior studies have shown that some of these closely spaced LAGs are annual, and therefore the inability to detect such marks could result in a downward bias in age estimates.
We assessed mitochondrial DNA diversity in Trionyx triunguis from the Mediterranean basin (22 samples) and continental Africa (4 samples). The continental African group comprised 4 different and newly described haplotypes, while the Mediterranean group consisted of only 1 previously known haplotype, with the nucleotide divergence between the 2 groups being 1.5% ± 0.7%.
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