The Philippine forest turtle, Siebenrockiella leytensis, is endemic to Palawan and Dumaran islands. Its limited distribution, exploitation, and habitat destruction are the main threats to this Critically Endangered species. The populations of 5 sites in northern Palawan were assessed in terms of habitat, population size, density, and structure. Fieldwork was conducted from 28 January to 15 June 2007. Turtles were collected through visual encounters and with pit fall and baited funnel traps. All captured individuals were marked and released after standard measurements were taken. Considering the relatively short sample period, populations were considered “closed,” that is, with negligible birth, death, and migration. Population size was then estimated using statistical analysis. Information on exploitation was gathered through interviews. Surveys revealed various degrees of habitat destruction and different levels of exploitation among sites. Population size estimates varied from 10 to 110 individuals per site, and in the majority of sites, adults were most prevalent. Densities ranged from 4.4 to 121.7 (mean 39.3 ± 49.5) individuals/ha. The highest density and largest population were found at the least disturbed site. Low densities were recorded in the more disturbed habitats, presumably as a result of exploitation. In 3 of the 5 sites turtles are heavily exploited either for local food consumption or for the international pet trade. Findings justify its current status as Critically Endangered. In situ conservation of the most pristine population (Site I) is recommended in line with further research on the biology, ecology, and distribution pattern of the species.

Asian turtles have declined substantially in recent decades because of the large-scale collection of wild individuals for the food, pet, and medicine trades. This has hampered studies into the ecology and natural history of turtles in their natural habitats because many species have become so rare that they are simply unavailable for study. One way to re-establish or supplement these turtle populations is through translocation (either of wild-caught individuals or those raised in farms). However, successful translocation is partly dependent upon released individuals maintaining site fidelity. We translocated 16 big-headed turtles, Platysternon megacephalum, in southern China to study their movements and microhabitat use in the wild and use this information to evaluate the feasibility of translocation as a conservation technique for this species. Translocated turtles generally moved short distances (daily range: 0–89.6 m), with males moving further than females and both sexes moving further at night than during the day. Additionally, big-headed turtles rarely used terrestrial habitats (the maximum distance an individual was located from the stream was 5.8 m) and remained hidden in refugia most of the time. Some sex differences in microhabitat use were also apparent; females were visible less often, spent more time on land (which coincided with the nesting season), remained closer to the stream bank, used shallower water, and used different types of refugia than males. The very short distances that big-headed turtles moved, combined with their consistent fidelity to the stream and cryptic behavior, all suggest that this species would be a good candidate for larger-scale translocation experiments. To our knowledge, this is the first published study of movement patterns and habitat use of translocated semiaquatic or aquatic turtles outside of Europe and the first published radiotelemetry study of turtles from mainland China.

The green sea turtle (also known locally as black turtle; Chelonia mydas) is 1 of 5 species of sea turtles found along the coast of the state of Baja California Sur, Mexico, where several bays and lagoon systems provide an important growth and feeding habitat. We characterized blood biochemistry values of 67 green turtles captured at 2 mangrove estuaries along the Pacific coast of the Baja California Peninsula, Mexico, from 2005 to 2007. Blood samples were collected from live turtles for biochemical analysis of 18 parameters and analyzed by physical state (healthy, injured), size classes, season, and geographic location. Green turtles showed differences in the variability of the biochemical parameters between the 2 sites. In Punta Abreojos, injured sea turtles had lower calcium (28%), potassium (28%), and inorganic phosphorus (34.5%) levels and higher cholinesterase activity (16%) compared to healthy turtles. Juvenile turtles collected in Bahía Magdalena had higher glucose levels (34%) than subadults. Levels of triglycerides, total proteins, and albumin correlated positively with size. During the summer and during the years 2005 (Bahía Magdalena, BMA) and 2006 (Punta Abreojos, PAO), individuals had significantly higher concentrations of lipid (cholesterol and triglycerides), glucose, uric acid, and protein. Differences in the habitat, food availability, and environmental conditions between BMA and PAO were reflected in the variability of the biochemical parameters when compared by different factors, such as physical state, size, and seasonality. This is the first report of blood biochemical values of green sea turtles in the Pacific coast of Baja California, Mexico. All serum chemistry values of green sea turtles were within published reference ranges of healthy sea turtle population.

Body condition index is used as a measure for an individual's condition, usually with reference to its nutritional status and the energy reserves. Reproductive success, survival, and thus, population dynamics, depend on body condition of the organisms. In this study, the seasonal and annual body condition factor (a) and the relative body condition index (K_rel) were estimated from the length–weight relationship of green turtles (Chelonia mydas) collected in 3 coastal lagoons of Baja California Sur during 2005–2007. Seasonal and annual differences in a, and differences between study sites and physical appearance (healthy or injured) of K_rel were analyzed. Juveniles were the predominant age class (< 77 cm straight carapace length). Green turtles from Punta Abreojos (PAO) had a lower K_rel than individuals of Laguna San Ignacio at a given size. In Bahía Magdalena (BMA) and PAO injured green turtles had a smaller K_rel than turtles classified as healthy at a given size. Additionally, the increase in K_rel per cm of straight carapace length of injured green turtles from PAO was lower than that of healthy ones. Body condition factor, a, varied between years in turtles from PAO, being highest during 2006. An increasing tendency in a, from winter to summer, was observed in PAO and BMA. The periods when green turtles had the highest body condition factor a (summer, 2005 BMA, 2006 PAO) coincided with periods of highest serum concentrations of glucose, proteins, lipids, calcium, and uric acid; nevertheless, the relative body condition index was not correlated with those parameters. The relative body condition index resulted in a simple and sensible method that provided an overall trend of the data under a number of stress conditions, detecting differences also between injured and healthy individuals. The body condition factor, in conjunction with blood biochemistry parameters, proved to be a useful tool as biomarkers of the apparent physical and nutritional status of the green sea turtles.

In riverine systems, the construction of locks and dams may present barriers to movement for aquatic organisms and effectively fragment otherwise continuous populations. We examined the spatial ecology and population genetics of northern map turtles (Graptemys geographica) in the Trent-Severn Waterway (TSW), Ontario, Canada. We hypothesized that the locks and dams on the TSW are fragmenting map turtle habitats and creating barriers to movement, and predicted that turtles from fragmented habitats have significantly reduced home range sizes and daily movements compared to turtles from unfragmented habitats, and that populations on either side of a lock and dam would be genetically distinct. Home ranges and average daily movements were smaller for turtles from fragmented habitats compared with continuous habitats, indicating that locks and dams are restricting mobility. However, populations in fragmented habitats showed none of the predicted genetic consequences of fragmentation (e.g., reduced heterozygosity and allelic richness, differentiation across a barrier). Genetic data may be reflecting historic population structure because only a few turtle generations have passed since the construction of the locks and dams about 100 years ago. Additionally, our genetic data may not be sufficiently robust to detect differentiation at this relatively small geographic scale. Our study highlights the conservation importance of examining multiple facets of a single potential threat, especially for long-lived species that may show differences in short- and long-term effects of fragmentation.

A decreased tannin load during 2006–2007 in a northern Florida blackwater river allowed us to make observations on the ecology of the Suwannee cooter (Pseudemys concinna suwanniensis), a species otherwise usually studied in clear, spring-fed rivers. We conducted a capture–mark–recapture study of this protected species and recorded the locations of marked individuals throughout a > 7.4-km study site for > 5 months. Large Suwannee cooters can be highly vagile and are capable of covering long distances rapidly (> 1.5 km in a day), with few individuals found > 5 km from previous capture locations. For large turtles, the propensity to move across different habitats and the size of the actively used linear home range varied extensively and were best explained by individual variation rather than by sexual differences. We observed an abundant population, including all size classes. Turtle distribution throughout the site was unequal among river sections and was positively correlated with the number of basking sites and water depth. We recommend basking counts to monitor population trends in blackwater rivers, especially under conditions of high tannin concentrations when hand capturing turtles is difficult.

Health evaluations were conducted in the northwestern Atlantic for 19 leatherback turtles, which included 12 turtles directly captured as part of a satellite telemetry study and 7 turtles entangled in fishing gear. Assessment included physical examination; determination of heart rate and respiratory rate; and hematologic, plasma biochemical, nutritional, toxicologic, parasitologic, and microbiological investigations. Significant differences were found between directly captured and entangled turtles for curved carapace length, curved carapace width, blood urea nitrogen, chloride, sodium, triglycerides, relative heterophil count, relative monocyte count, relative and absolute eosinophil count, pH, bicarbonate, lead, and beta-hydroxybutyrate. Directly captured turtles showed evidence of mild respiratory acidosis. Significant differences were found between sexes for curved carapace length, curved carapace width, total protein, globulin, sodium, relative monocyte count, gamma-globulin, and anion gap. Relatively high blood concentrations of selenium and cadmium were found in all turtles.

Homopus signatus signatus is a small tortoise that is endemic to arid northwestern South Africa, where its range is threatened by aridification. It is not clear how the taxon will respond to an aridifying habitat, emphasizing the need for population monitoring. I conducted a mark–recapture study over 5 years with above- and below-average rainfall to analyze population structure, abundance, apparent survival, and effects of rainfall. The population had a continuous size-class distribution and contained similar frequencies of males, females, and juveniles, indicative of a viable population with reproduction and recruitment into adulthood. It consisted of transient and resident individuals, with an abundance of 16–21 resident tortoises/ha. High spring activity levels appeared to result in high (0.35–0.94) recapture rates, which differed among years as a result of different search efforts. Apparent annual survival rates of residents depended on group and increased with shell volume, ranging from 0.74 to 0.99. Although females were the larger sex, their apparent survival tended to be slightly lower than male survival, possibly because of high female activity to accumulate nutrients for the production of large eggs. Rainfall had little effect on apparent survival, suggesting that physiological responses to drought exploited by H. s. signatus are effective in helping them survive. Consequently, mortality during current, periodic droughts does not seem to oppose recommended conservation measures to improve adult survival and delay detrimental effects of aridification on growth and reproduction.

Morphological variation in size and shape of organisms has physiological, ecological, and evolutionary relevance. In this context, an important step in the identification of evolutionary units is to identify groups of populations occupying a continuous geographic space, at both genetic and morphological levels. The freshwater turtle Hydromedusa is endemic to the Neotropical region and inhabits water bodies of the Paraná–La Plata basin of Argentina and coastal streams of Brazil and Uruguay. The genus is present in the fossil record since the Paleocene (56 mya) and currently consists of only 2 extant species. Hydromedusa tectifera has the widest distribution, from Santiago del Estero in Argentina to the State of Sao Paulo in Brazil. The goal of this work was to study the patterns of morphological variation of H. tectifera through most of its geographical range. Herein, we report morphological variation of carapace shape in this species associated with developmental and historical parameters. Our results support the hypothesis that at least part of the morphological variation found is associated with population variation among basins, possibly as a result of reduced gene flow among their populations. This variation is shown in both linear and geometric morphometry analyses. Sea level fluctuations that occurred in the region during the last 15 million years could have caused the current differentiation.

A nonnative haplotype of Phragmites australis (Cav.) Trin. ex Steudel has recently expanded its range to become a dominant invasive species in many areas of North America and has thereby become a conservation concern. It is highly aggressive and outcompetes surrounding vegetation by resource competition. Also, by successfully modifying the habitat, P. australis can displace native plant communities and negatively affect other organisms. Phragmites australis abundance has increased significantly at Long Point, Ontario, Canada, a highly sensitive area where 6 freshwater turtle species nest. At these high latitudes, turtles rely upon open, unshaded areas to provide adequate solar heat for nesting and select nest sites based on specific physical characteristics at the time of oviposition. The rapid expansion of P. australis has reduced suitable nesting habitat for many turtle species because the plants' growth during a season alters the microenvironment of turtle nests during incubation, particularly affecting nest temperature, the most important factor for embryo development. Phragmites australis is highly exploitative, and its uncontrolled invasion threatens the reproductive success of freshwater turtle species at Long Point and much of North America.

Populations of long-lived animals, such as semi-aquatic turtles, that depend on high survivorship of reproductive adults, are particularly susceptible to the negative effects associated with habitat modification in suburban areas. Survivorship of semi-aquatic turtles in suburban landscapes may be reduced as a result of a number of factors, including the elimination of appropriate nesting habitat and the introduction of human-subsidized predators. Unfortunately, few studies on turtle populations in anthropogenically modified habitats estimate vital rates, and researchers are rarely able to study populations both before and after development. We studied painted turtle (Chrysemys picta) vital rates at 5 ponds in the Charlotte Metropolitan area of North Carolina; 2 ponds and their surrounding habitat underwent development after the first year of study, 1 pond was on a golf course, and 2 were farm ponds. We used Program MARK to generate open population models examining the effects of location and sex on turtle survivorship. Our results showed relatively stable population densities over 4 years across all ponds, with the largest density (approximately 100 turtles/ha) occurring at a recently developed site. Among ponds, turtles had variable annual adult survivorship (ca. 60%–95%), and males generally had lower survivorship than females. Our results emphasize the importance of site-specific habitat factors that influence turtle population demography and indicate that for long-lived species, whose population densities may not respond immediately to habitat change, long-term monitoring efforts examining population vital rates are needed to more fully evaluate the effects of anthropogenic modification.

Reproduction in the red-cheeked mud turtle (Kinosternon scorpioides cruentatum) was studied in southeastern Mexico and Belize (Yucatan Peninsula) on the basis of museum and field-collected specimens. Adult females (mean carapace length [CL]  =  110 mm) were not significantly larger than adult males (mean CL  =  108 mm). Females matured at 100–105 mm CL and an estimated age of 9–10 years. Annual reproduction by females was apparently continuous for at least 10 months of the year (August–June), with the production of multiple annual clutches (possibly as many as 5) being typical and the number of clutches per year increasing with female size. Eggs exhibit diapause and embryonic estivation and apparently hatch in nature during the wet season (June–August) after up to 9 months in the nest. Modal clutch size was only 2 eggs (mean 2.2; range 1–4), and clutch size increased with female body size. Egg size averaged 31.5 × 16.6 mm and 5.5 g and did not vary with female body size. Relative egg mass (REM  =  mean egg mass × 100/[body mass − clutch mass]) averaged 2.3, was lower in larger clutches, and decreased with increased body size. Relative clutch mass (RCM  =  REM × clutch size) averaged 4.85, similar to that for the sympatric K. creaseri (4.5), the 2 lowest values reported for any studied Kinosternon population. RCM did not vary with female body size or clutch size. Females devote a relatively constant proportion of body mass to each clutch, and increases in reproductive output with size and age are apparently accomplished by increases in clutch size (but not egg size) and clutch frequency. This unusual suite of reproductive traits (small body size, small clutch size, production of up to 5 clutches per year, reduced relative clutch mass, and embryonic diapause and estivation) may have been instrumental in the success of this species at colonizing more of South America than any other Mesoamerican turtle genus or species and in less than 4 million years.

Long-term observations at El Cuyo, Mexico, show a spatial pattern of beach preference by hawksbill and green turtles nesting at that beach. The morphological features of this beach were examined to evaluate their influence on the nesting preferences of these 2 sea turtle species.

We report a field observation of an adult female leatherback turtle (Dermochelys coriacea) expulsing 2.6 kg of plastic debris from her cloaca while nesting in French Guiana. This field report sustains concerns about plastic ingestion by this endangered species and, further, the impacts of plastic debris to marine wildlife, and points out the needs for effective waste management in both terrestrial and marine habitats.

During the voyage of the Beagle, Charles Darwin collected a single juvenile tortoise from James (San Salvador or Santiago) Island in the Galápagos Archipelago. This specimen, often referred to as Darwin's “pet” tortoise was returned alive to England along with 3 other small tortoises and examined by J.E. Gray. The subsequent fate of the specimen has been the source of much speculation, and recent popular publications have variously proposed that the tortoise was transported to Australia (where it supposedly lived to an age of more than 175 years) or that it remained in England but disappeared without a trace. We discovered that Darwin's pet was indeed registered into the British Museum collection in 1837 and that it is still extant and clearly labeled on the inner face of the plastron as BMNH 1837.8.13.1 from James Island. These data were overlooked for more than 170 years, and 3 curators (Gray, Günther, and Boulenger) who published chelonian catalogues between 1844 and 1889 all failed to recognize this specimen as Darwin's tortoise, mentioning it only as a stuffed juvenile of unknown provenance. Günther referred the specimen to his newly erected Testudo ephippium, subsequently regarded as endemic to Abingdon (Pinta) Island, but confirmation of the specimen's James Island origin implies that Darwin's pet tortoise is, appropriately, referable to Chelonoidis darwini.

Human and natural factors threaten loggerhead turtle (Caretta caretta, Linnaeus 1758) survival in the western Mediterranean basin. Loggerhead stranding data in the south of Spain provide evidence that human activities are having a more detrimental effect on larger-sized loggerhead turtles. The straight carapace length of 162 individuals affected by natural causes averaged 35.15 cm; whereas, that of 179 individuals affected by human-related causes averaged 46.23 cm. The difference was highly significant.

Four new loggerhead turtle nest sites were discovered in 2006 and 2008 on Italian beaches at the northern limit of this species' nesting. Only 2 hatched, 1 with low success (33.3%) and 1 with a 92.2% success, whereas the other 2 failed to hatch after prolonged incubation (> 100 days), caused by low temperatures. Another 9 unusual loggerhead nests in the western Mediterranean have been recorded over the last decade, and because it is yet unclear what may be driving this behavior, further working is needed including establishing organized monitoring of potentially suitable beaches.

Seed dispersal capabilities by red-eared sliders (Trachemys scripta elegans) and common snapping turtles (Chelydra serpentina) in southwestern Missouri were investigated for mulberry (Morus spp.), barnyardgrass (Echinochloa crus-galli), and curly dock (Rumex crispus). Feeding trials conducted on these seeds demonstrated that seed damage was low and percentage of germination of turtle-passed seeds did not exceed controls for any seed species tested. These turtle species are capable of dispersing mulberry, barnyardgrass, and curly dock seeds to areas near pond margins and to more distant locations during overland movements.

Few studies have described the natural history of Phrynops geoffroanus in anthropogenic environments. We analyzed the stomach contents of 39 P. geoffroanus from the Anhanduizinho River, Campo Grande, Mato Grosso do Sul, Brazil, from September 2004 to April 2005. We verified the presence of invertebrates (Odonata larvae and mollusks), fish, and plant material. The primary food item ingested all year by the P. geoffroanus examined was the larval stage of Chironomus sp.

We present baseline data on the distribution and abundance of invasive red-eared slider turtles (Trachemys scripta elegans) in the Sacramento River basin of northern California and discuss their possible impacts on the native western pond turtle, Emys [ =  Actinemys] marmorata. Although T. s. elegans may be able to spread throughout the drainage, our surveys suggest that it is currently concentrated near urban areas and relatively rare throughout most of the areas where large Emys marmorata populations persist. We also confirm 2 additional localities where extralimital breeding of T. s. elegans is occurring.

Turtle carapaces clearly function as antipredator adaptations, but their varied structure has rarely been matched to differential predation pressure in nature. In addition, the role of antipredator behaviors, and how they interact with morphological defenses in turtles, is poorly understood. Here we show that a small turtle, Pelusios subniger, is found predominately in pools and watercourses where the Nile crocodile, Crocodylus niloticus, a species that imposes intense predation pressure on them, is absent. Our ecological data are consistent with the interpretation that P. subniger can share the same ecological landscape with C. niloticus through behavioral avoidance.

During the last two weeks of November 2008, we recorded 115 tracks of nesting females and 219 hatching events by green turtles (Chelonia mydas) on one of three beaches on Isla Clarión, Archipelago Revillagigedo, Mexico. Combined with single surveys of the other two suitable beaches, we estimated as many as 500 green turtle nests were laid on Isla Clarión in two 2-week periods, thus signaling the importance of Isla Clarión as an important nesting site for this endangered species in the eastern Pacific Ocean. Further study and guaranteed protection to ensure the conservation of this population are recommended.