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Resource partitioning in communities is often achieved by sympatric species having different morphologies that allow them to access different resources. This is because differences in morphology influence an organism's capability to perform a task that is relevant to their ecology. Here, we compare limb, shell, and head morphology, swimming performance, habitat use, and diet of three species (Rhinoclemmys rubida , R. pulcherrima, and Kinosternon chimalhuaca) that co-occur in the tropical dry forest of Chamela, Jalisco, Mexico. We found that these species do not overlap in both habitat or diet, and the overlap that we observed in habitat was contrasted by differences in diet. We also found a consistent relationship among limb and shell morphology, swimming speed, and habitat. Rhinoclemmys rubida occupies the driest deciduous forest atop and along hills, has shorter hands, less interdigital webbing, longer plastrons, more-domed shells, and slower swimming speeds in proportion to body size. In contrast, Kinosternon chimalhuaca exclusively occupies arroyos or seasonal streams, has longer hands, more interdigital webbing, smaller plastrons, less-domed shells, and faster swimming speeds in proportion to its body size. Rhinoclemmys pulcherrima was found in all habitats and intermediate in morphology and swimming speed between the other two species. Therefore, in this study system, limb and shell morphology are good indicators of habitat differences between turtle species. These differences are likely due to the influence that limb and shell morphology have on swimming performance. Relationships between head morphology and diet were less clear, which might be the result of changes in behavior or habitat rather than morphology. Patterns of resource partitioning in Chamela seem to coincide with other studies of turtle communities, which suggests that relationships among morphology, performance, and ecology that we observe here might be a general pattern across turtles. [ABSTRACT FROM AUTHOR]

The ecology of many ectotherms depends heavily on their ability to navigate the surrounding thermal environment in a manner that maintains body temperature (Tb) within or near some optimal temperature range at least some of the time. From April–December 2016, we measured shell temperatures (Ts) and water temperatures (Tw) in two Spotted Turtle (Clemmys guttata) populations in southeastern Georgia using iButton temperature loggers. We attached radio transmitters and iButtons to the carapace of adult Spotted Turtles (n = 18 and 11 in each population, respectively) in early spring. Temperature loggers recorded a Ts measurement every 90 minutes (accuracy = 0.5°C), and we restricted our analyses to temperatures recorded between sunrise and sunset. Monthly mean Ts ranged from 12.3±3.4 to 27.1±2.7°C (SD), and seasonal variation accounted for a majority of the observed variation in temperatures. We found a strong positive correlation between weekly mean Ts and weekly mean Tw at one site that remained flooded throughout the study (P < 0.0001, R2 = 0.99). Tw could not be measured at the other site because it dried completely early in the study. Spotted Turtles did occasionally (<5% of total temperature observations) bask to raise Ts above that of the surrounding Tw. Gravid females achieved significantly higher daily maximum temperatures (26.2°C) than males (24.5°C) during the four weeks surrounding egg development (P = 0.043). In general, Spotted Turtles at the southern end of their range appear to spend a majority of their time conforming to environmental temperatures that often fall within the preferred range for the species. [ABSTRACT FROM AUTHOR]

Long-term studies on wildlife populations are necessary to track population abundance and shifts in demography over time, yet such studies are difficult to plan, fund, and conduct and are therefore rarely undertaken. Such studies are especially important for long-lived species that can persist for long periods of time with little to no reproductive output or recruitment. We conducted two population studies spanning a 30-year time frame on the globally endangered Spotted Turtle (Clemmys guttata) on protected land in the center of their range. Spotted Turtles are endangered in Canada, listed as globally endangered on the IUCN red list, and declining throughout their range. However, there has only been one previous long-term study tracking their long-term population trajectory. Here, we use mark–recapture data collected over a 30-year time frame and report that the estimated population size of Spotted Turtles has decreased by 49% at our study site despite the habitat residing with a protected area. This decline was concurrent with a significant increase in the proportion of larger individuals within the population, indicating a lack of recruitment into the sub-adult stage class. These results highlight the value of long-term studies in monitoring population changes of long-lived species, the importance of active management within protected areas, and the ability of long-lived species to persist for long periods of time despite having little recruitment and a declining population trajectory. [ABSTRACT FROM AUTHOR]

Phenotypic variation within a species can be associated with genetic differentiation and varying environmental conditions among populations and their habitats. The relationship between environmental conditions and phenotype expression can influence evolutionary potential, possibly affecting rates of speciation or ecological character displacement. Here, we use a geometric morphometric approach to investigate if shell-shape morphology variation is influenced by the location within the drainage basin (cumulative drainage area) in a freshwater turtle, Graptemys nigrinoda. Drainage area is used due to its hierarchical controls on hydrology, channel morphology, and thus instream hydraulics that comprise the physical habitat hypothesized to drive differences in shell morphology. In addition, we investigate the extent to which salinity may drive similar morphological variation in coastal range extents. We use spatial regression models to assess how geographic variation in carapace length and shell height is influenced by cumulative drainage area and marsh habitat type (i.e., freshwater or brackish marsh). We found that carapace length, shell height, and carapace shape variation covaried with cumulative drainage area in both sexes. Shells become larger and more domed with larger cumulative drainage areas. Additionally, turtles from larger cumulative drainage areas are characterized by distal shifts in costal and marginal scute orientation and medial shifts in costal scutes. The morphological response to hydrogeomorphic controls on physical habitat (e.g., channel morphology and hydrodynamics) as represented through drainage area is predictable and reported in several turtle species. Although others have invoked a predator response hypothesis for larger, more domed shell phenotype (i.e., stronger shell to resist crushing), we propose an alternative hypothesis that there is a potential locomotive advantage of a domed shell phenotype in lentic habitats likely related to buoyancy (i.e., greater volume to mass ratio), which needs further research. Furthermore, increased body size could likely be a selective advantage for inhabiting resource-rich brackish water habitats with increasing dietary diversity. Because these phenotypes (flattened shell and large body size) are associated with locomotion efficiency, our results suggest that gene flow is potentially impeded by distinctly different environmental conditions, providing further evidence for continued or maintained divergence between suggested subspecies within Graptemys nigrinoda. [ABSTRACT FROM AUTHOR]

Understanding how environmental factors influence various aspects of freshwater turtle health remains an important yet understudied topic within the context of individual–environment interactions. This is particularly true of host-associated bacterial microbiota, which are being increasingly recognized as a significant and understudied topic in the context of individual turtle health. While this area of work has expanded in certain areas, research efforts remain limited with regard to host–microbiota interactions in the context of habitat contaminants. Specifically, the commonly used herbicide, glyphosate, is of interest due to its massive worldwide use and known effects on various organisms. Effects of captivity on host-associated microbial community structure also remain largely unknown in various non-model organisms. To address these unknown effects of Roundup® and captivity on host-associated microbiomes, we examined the effects of low-level Roundup® exposure and captivity on the cloacal microbiota of the False Map Turtle, Graptemys pseudogeographica. We determined the effect of glyphosate by taking cloacal swabs pre- (0 h) and post-exposure (72 h) and examined microbial community beta- and alpha-diversity through 16S rRNA gene high-throughput sequencing. The results of this study indicate that low-level, short-term glyphosate exposure does not significantly alter the microbiota structure of G. pseudogeographica. However, there was a significant decrease in microbial community beta-diversity over time, confirming a trend that has been observed to a limited extent in other non-model organisms when put in laboratory conditions. These results are useful in understanding the baseline cloaca microbial community structure of G. pseudogeographica, as well as the implications and limitations of laboratory-based microbiota studies. Furthermore, this work suggests that low-level and short-term glyphosate exposure does not have a significant effect on the cloacal microbial community structure in wild-caught G. pseudogeographica. [ABSTRACT FROM AUTHOR]

The article presents profile of herpetologist Janis Arnold Roze who researched about life and its power. It mentions that Roze along with his brother Jesús Hoyos have collected reptiles and plants on Margarita Island in Venezuela; and wriiting articles on peculiarities of natural history and popular culture of turtles. It also mentions that Roze has worked at the Universidad Central de Venezuela; and has worked in field of biological and human sciences.

The Eastern and Florida Chicken Turtle subspecies (Deirochelys reticularia reticularia and D. r. chrysea) exhibit nesting cycles that are atypical for aquatic North American turtles, with nesting occurring in the fall, winter, and early spring. The reproductive cycles of the western subspecies (D. r. miaria), however, have not been studied. Therefore, we monitored the reproductive status of female D. r. miaria in 2012 and 2013. In our populations, both male and female D. r. miaria were inactive on land from mid-July to mid-March. This differs from the activity patterns of the other subspecies in which females typically remain active into the fall and sometimes winter. Also, in contrast to the nesting patterns of D. r. reticularia and D. r. chrysea, female D. r. miaria developed follicles in the spring and summer (March-July) and contained eggs in the summer (May-July). Therefore, we conclude that the Western Chicken Turtle exhibits a nesting pattern that is more similar to that of other sympatric species in the family Emydidae than it is to other subspecies of D. reticularia. [ABSTRACT FROM AUTHOR]

Indeterminate growth, although widely accepted in reptiles, has questionable supporting evidence. In turtles and tortoises, evidence for indeterminate growth is mixed depending on the species, population, and individual. Using a captive colony of desert tortoises, I explored three questions about adult growth: 1) Do tortoises experience growth at reproductively mature size classes? 2) For those adults that experience growth, is growth continuous throughout adulthood? 3) Are there differences in growth and size between males and females? I found that adult tortoises maintained growth potential past reaching sizes deemed sexually mature. Growth rate was strongly related to size. Larger individuals grew less than smaller ones, and the majority of individuals appeared to stop growth at some point during adulthood. Additionally, there was little difference in growth rate between males and females, although males did achieve larger sizes than females. In summary, desert tortoises appear to display a finite growth potential that is regulated by size, sex, and potentially age, but both sexes can grow well past sexual maturity. [ABSTRACT FROM AUTHOR]

Omnivory is ubiquitous in aquatic and terrestrial ecosystems and may increase stability of food webs. Turtles are long-lived and among the most abundant organisms in lentic aquatic habitats. Many species are omnivores and thus may be especially important in regulating ecosystem dynamics in these systems. Turtles are also one of the most threatened vertebrate groups in the world; if they indeed play pivotal roles in lentic ecosystems, their declines may disrupt or even destabilize those ecosystems. In order to assess the role of turtles in an aquatic ecosystem, we examined sources of primary production, trophic structure, and ontogenetic diet shifts of five species of turtles, other herpetofauna, and fish in a large shallow lake in northern Florida. Stable isotope analyses (δ13C and δ15N) of 42 species of animals and five sources of primary productivity revealed that macroalgae and/or particulate organic matter were the foundation of the food web. Trophic structure of the herpetofauna and fish indicated a high degree of omnivory (TPs of 3-4), few specialists at high trophic levels (TP ≥ 4.0), and few strict primary consumers (TP = 2.0). Several predatory fish ( Micropterus salmoides, Lepomis gulosus, and Pomoxis nigromaculatus) and herpetological predators (e.g., Alligator, Nerodia) were functionally trophic omnivores with trophic positions lowered by predation on primary and low trophic position secondary consumers. We found two major divisions in the trophic structure of turtles-an herbivore ( Pseudemys floridana) and four omnivores ( Apalone ferox, Chelydra serpentina, Sternotherus odoratus, and Trachemys scripta). There were at least three types of omnivores, species that are generalist feeders throughout their life (e.g., C. serpentina, S. odoratus), species that change their trophic position during ontogeny (e.g., A. ferox), and species with the same trophic position through ontogeny but resulting from different diet composition as juveniles and adults (e.g., T. scripta). Trophic position of some species indicated that even when turtles are primarily predatory, they also function as vegetative consumers and facultative scavengers (e.g., T. scripta, S. odoratus, A. ferox). Given that omnivory is a critical process that can stabilize food webs, there will certainly be dramatic shifts in how energy and nutrients flow through these lentic ecosystems if turtle populations decline. [ABSTRACT FROM AUTHOR]

Reproductive success is often difficult to ascertain in reptiles because of inconspicuous reproductive behaviors such as courtship that occurs in aquatic habitats and cryptic breeding outcomes such as multiple paternity and sperm storage. We corroborated field observations of mating behavior with genetic parentage analysis to assess the mating system and reproductive success in the rare Blanding's Turtle (Emydoidea blandingii) within a fragmented landscape in Will County, Illinois. During four consecutive years of radio-telemetry monitoring, we observed promiscuous mating behavior among males and females. Parentage was strongly skewed (one male sired 38% of 272 offspring) and multiple paternity was rare (11% of 28 clutches). Both males and females produced offspring with multiple individuals over the course of the study, but parentage did not always correspond with observed mating attempts; only 41% of male mating attempts observed in the field corresponded with sired offspring. For males, number of female mates inferred from paternity analysis was positively correlated with total number of offspring sired. No correlation was found between relatedness of observed mating pairs and hatching success. Repeat paternities in clutches were detected among years, with one confirmed instance of across-season sperm storage. High variation in reproductive success and low levels of multiple paternity in Blanding's Turtle in Will County compared to other areas may be attributed to habitat modification, small population size, and disruption of the mating system. [ABSTRACT FROM AUTHOR]

Species inhabiting running waters have evolved life-history strategies and morphological characteristics that allow them to survive in fluctuating river environments. Riverine turtles often have behavioral responses associated with seasonal drying and flooding, and morphological variation that is correlated with physical instream habitat. We compared movement behavior, body size, and body condition of Western Pond Turtles (Actinemys marmorata) under two different flow regimes: a regulated reach with dam-influenced perennial flow and a naturally intermittent reach upstream of the dam. We used radiotelemetry to track the seasonal movements of turtles at both sites and compared body size and condition through data gathered during snorkel surveys. We found that timing of migration was significantly influenced by flow regime. Turtles in the intermittent reach departed the river earlier than those in the perennial reach, and also migrated to the river earlier in the spring. Overall, turtles from the intermittent reach spent less time annually in the water, and adults were significantly smaller and had lower body condition compared to those from the perennial reach. In our study system, a dam converted part of a historically intermittent reach to a perennial one; this apparently had some positive effects, such as increased foraging time, larger body size, and better body condition. However, there may be tradeoffs with regard to habitat quality for rearing juvenile turtles to assure recruitment and persistence of the population. [ABSTRACT FROM AUTHOR]

We quantified illegal and unmonitored harvest of three endangered sideneck turtles (Podocnemis spp.) by examining discarded turtle shells in 29 riverine communities both up- and down-river from the Arrau Turtle Wildlife Refuge in the Middle Orinoco, Venezuela. We compared harvested turtle sizes to those captured during in-water research surveys to determine harvest selectivity. We found fresh sideneck turtle shells in most communities visited; carapaces and plastrons from P. expansa were the most abundant despite their protected status. Turtle harvest was skewed toward females in all species, and toward juvenile P. expansa and adult P. unifilis and P. vogli. Considering historical accounts of widespread turtle husbandry in the area, Podocnemis spp. life history, and population recovery for these species in community-based conservation programs elsewhere in South America, we recommend community-managed captive breeding of faster-maturing P. unifilis and P. vogli to satisfy turtle consumption needs. These measures, along with improved nesting-beach protection, may allow recovery of populations of P. expansa and make possible their legal subsistence harvest in the future. [ABSTRACT FROM AUTHOR]

Currently, little is known about the seasonal variation of corticosterone (CORT) levels, either baseline or stress response, within freshwater turtles. We conducted a seasonal CORT study with a species of freshwater turtle, Graptemys flavimaculata (Yellow-blotched Sawback; family Emydidae), that is endemic to the Pascagoula River system of southeastern Mississippi. Graptemys flavimaculata is commonly observed while basking on deadwood snags, with us using basking traps and dip nets as active capture methods. We caught both male (n = 60) and female (n = 49) turtles during the months of April--October during 2007 and 2008. Immediately after capture, we collected an initial blood sample, confined the turtle for 35 minutes, and then took a second blood sample. Competitive binding radioimmunoassays were done to determine CORT levels. Time zero CORT levels for both sexes were generally lower than previously reported levels for other turtle species, likely due to the trapping methods used. By time 35 min, CORT levels were significantly elevated relative to initial levels. We did not detect seasonal differences in time zero CORT levels for males or females. However, seasonal differences in time 35 CORT levels for males were detected, with higher levels observed during summer months (July, August) relative to spring (April) and fall (October) months. Seasonal differences were also detected in time 35 CORT levels of females, with lower levels observed during July (nesting season) relative to September. This study provides novel information and insight into the differences in seasonal physiological demands for this species, and aquatic turtle species in general, while also providing probable connections of physiology to seasonal life history events. [ABSTRACT FROM AUTHOR]

In an effort to identify long-term changes in a river turtle community and its habitat, we reexamined the turtle community in a 4.6 km section of the North Fork of White River (NFWR), Ozark County, Missouri, that was previously studied between 1969 and 1980. We compared data collected in 2004 to data from 1969 and 1980 to determine if alterations in the habitat, community composition, or Northern Map Turtle (Graptemys geographica) population size and structure had occurred. Previous studies showed that the population of G. geographica declined between 1969 and 1980. Our results indicate that the population of G. geographica failed to rebound by 2004. The population of Red-eared Sliders (Trachemys scripta elegans) that established in the research section between 1971 and 1980 expanded their distribution between 1980 and 2004. Threats to the population of G. geographica included lack of basking sites, increased human recreational use of the stream, and water quality degradation. [ABSTRACT FROM AUTHOR]

Two fossils from the diverse St Bathans Fauna from Early Miocene sediments in New Zealand are described and identified as from a large, probably terrestrial turtle. They are the first freshwater or terrestrial turtles to have been reported from the Cenozoic of New Zealand. Recent authors have used the absence of turtles and species they considered unlikely to raft to New Zealand to debunk the long held theory that an element of the New Zealand fauna was ancient and vicariant and had evolved on what David Bellamy called Moa's Ark. The discovery that large non-marine turtles were once present in New Zealand adds to a growing and diverse list of terrestrial taxa known from Zealandia shortly after its maximum inundation in the Late Oligocene. Many of these taxa, including a diverse herpetofaunal component, represent lineages endemic to New Zealand and had poor dispersal capabilities, supporting the long held view that a part of the Zealandian fauna was vicariant in origin. [ABSTRACT FROM AUTHOR]

Determining the demographic structure of turtles is important to understanding their population status and conservation needs. Concern has been raised for the long-term persistence of the Western Pond Turtle (Actinemys marmorata) based on demographic analyses using size while ignoring age. Here, we compare the size versus age structures, and examine growth curves, for turtle populations from four sites in the Klamath-Siskiyou ecoregion of northern California and southern Oregon. We show that age structure does not correspond to size structure for two populations. Also, the most abundant of these populations had relatively few small turtles, which suggests inability of previous researchers to locate small turtles. Growth rates and adult size differed among populations, with turtles from two sites in the Coast Range significantly smaller and slower growing than turtles from either a reservoir on the eastern lower slopes of the Coast Range or the Klamath Basin east of the Cascade Mountains. Neither air temperature nor elevation explained the differences in size and growth rates. We hypothesize that larger body size and faster growth rates for some populations of A. marmorata may be due to high local productivity. We show that use of size alone gave an erroneous interpretation of population structure. Finding a few small-sized turtles in populations may not represent a lack of recruitment but, instead, a need to determine the proportion of young turtles based on their actual ages. [ABSTRACT FROM AUTHOR]

Because many species of semi-aquatic turtles have specific habitat requirements and unique life history characteristics, they are particularly vulnerable to anthropogenic habitat modification. The federally threatened Bog Turtle (Glyptemys muhlenbergii) requires specialized wetland habitats, such as bogs and fens, in the eastern United States and often occurs in isolated populations. To develop a more a detailed understanding of the habitat use, movement, and thermal biology of Bog Turtles, we radiotracked and monitored the temperatures of 11 adult Bog Turtles at an isolated Piedmont meadow bog in North Carolina from May 2007 to March 2008. We found that turtles used soft, shallow mud habitat in the bog, but moved to a streambed when the bog became dry. While in the bog, turtles were often found within or underneath woody debris. Although most turtles resided exclusively in the southern part of the bog and the stream, two male turtles made substantial over-land movements away from the bog exceeding 130 m. All but one turtle overwintered in a streambed adjacent to the bog. Turtles overwintering within stream habitat were not exposed to temperatures below 0°C, but one turtle that overwintered in the bog did reach below-freezing temperatures. This study suggests that high-quality bog habitat and habitat heterogeneity are critical for populations living in isolated and dynamic habitats. However, maintenance of corridors between suitable habitats may be necessary for the long-term survival of Bog Turtle populations. [ABSTRACT FROM AUTHOR]

During two nesting seasons we monitored 19 naturally Incubated nests of Podocnemis lewyana obtained from two sites in the Mompos Depression of northern Colombia. We incubated another nine nests in the laboratory under similar humidity conditions, but at six different temperatures. We sexed the hatchlings obtained from all nests to confirm for the first time the occurrence of temperature-dependent sex determination in this species and quantify sex ratios and the pivotal temperature for this population. In both nesting seasons, the majority of the nests in the field produced hatchlings of both sexes, but sex ratios differed between study beaches/years. The pivotal temperature documented (33.4°C) appears to be among the highest reported for a turtle species. Incubation conditions in the naturally incubated nests also influenced hatching success rates and incubation periods, but not hatchling size or weight. Hatchlings obtained from the nests incubated in the laboratory were reared for one month In order to study the Influence of prehatching factors on growth rates. In these nests we documented maternal effects on egg size, Initial hatchling size, and weight and growth rates. Incubation temperature also influenced hatching success rates, sex ratios, growth rates, and hatchling size, but not hatchling weight. [ABSTRACT FROM AUTHOR]

The high densities of freshwater turtles, along with their Iongevities and tendencies toward omnivory, can make them critical influences on the energy flow in lakes and the resilience of lake food webs. Despite this potential importance, there is little understanding of whether turtle abundances are driven by bottom-up (productivity) or top-down (predation) vectors. In this study I examined the environmental correlates of abundance of three dominant turtle species in 17 northern Florida lakes that span a gradient in primary productivity. I examined the associations between the abundances of the Yellow-Bellied Slider (Trachemys scripta), Florida Cooter (Pseudemys floridana), and Florida Softshell Turtle (Apalone ferox) and 18 environmental factors that varied either discretely or continuously across the lakes. Mantel analyses revealed significant associations between abundance of T. scripto, P. floridana, and A. ferox and periphyton and presence of mud and muck substrates, revealing a significant bottom-up influence. However, abundances were also associated with the presence or absence of alligators, important predators of turtles, indicating a significant top-down influence. The abundances of P. floridana and A. ferox were correlated with additional factors that suggest a role for specific dietary items and trophic position. The results indicate that both bottom-up and top-down controls are important limiting factors to turtle populations and implicate turtles as critical elements in the structure and, perhaps, the stability, of food webs in southeastern lakes. [ABSTRACT FROM AUTHOR]

Many important questions in ecology and conservation biology require assessment of the body condition of animals, which is often achieved using mass and length data. However, fully quantitative condition indices can be difficult to obtain in the field for large taxa like marine turtles. Therefore, rapid visual-assessment techniques for categorizing condition can be useful for field studies. Here, we test whether a visual method of categorizing body condition in the Green Turtle (Chelonia mydas) based on the shape of a turtle's plastron is comparable to two commonly used body condition indices derived from mass and length measurements. Condition scores for both mass-length indices varied in the expected manner with our visual condition categories, verifying that the rapid visual assessment technique accurately reflects differences in body condition. This technique should aid many field studies of turtles where body condition data are required hut mass data cannot easily be obtained. [ABSTRACT FROM AUTHOR]

Sources of body temperature (Tb) variation in freshwater turtles are known for very few species. Using surgically implanted, temperature-sensitive radiotransmitters in Midland Painted Turtles (Chrysemys picta marginata), we assessed Tb variation in relation to sex, microhabitat use, weather conditions, and water temperature (Tw) in a marsh system in northern Michigan. Diel Tb cycling occurred regardless of weather conditions and included monotonic declines during late evening and early morning hours, a late morning warming phase, a mid-day spike, and afternoon oscillations. Males maintained significantly higher mean Tb than females during the 0000-0600 h time period but not at other times during the day. During the nesting season and during all summer and fall months, sex did not explain any variation in mean daily Tb, but males had significantly lower mean daily Tb variability (CV Tb) than females. Mean daily Tb and CV Tb were significantly lower on overcast days than on sunny days, and females maintained significantly greater mean daily Tb than males on cloudy days. Habitat use affected mean daily Tb, where turtles that used the open-water microhabitat had higher and less variable Tb than turtles that used the edge microhabitat for at least part of the day. Overall, mean total daily distance moved (TDDM) was greater in males than in females although the effect was weak. Mean TDDM was significantly greater on sunny days than on cloudy days, and greater in turtles that used open-water microhabitats than in turtles that used only the edge microhabitat. Mean daily Tb began to decline in October, but mean TDDM, and therefore activity, did not occur until November. Daily movements ceased when Tw fell to 2.0-3.9°C in December and January. [ABSTRACT FROM AUTHOR]

The use of terrestrial habitat by freshwater turtles is receiving increased attention by herpetologists, driven in part by conservation efforts to protect critical upland habitat. I report on a high degree of non-nesting terrestrial activity by Chrysemys picta in Virginia. During a three-year project, 60 individual adult turtles were followed by radiotelemetry, primarily during the summer, with 22 of them being detected on land. Fifteen turtles dispersed overland at distances up to 3300 m, two turtles nested, four turtles aestivated on land for a mean of 34 days, and an adult male overwintered on land for approximately 290 days. Terrestrial activity was evidently prompted by drying of the home ponds. Most available upland habitats were used, with slight preferences by dispersing turtles for wooded habitats and by aestivating turtles for non-wooded habitats. Aestivation on land by C. picta has rarely been reported but may be fairly common during periods of drought. Overwintering on land by adult C. picta has not been reported and will require additional research to explain the physiological responses needed to survive. This study underscores the importance of upland habitat in the life history and conservation of freshwater turtles. [ABSTRACT FROM AUTHOR]

The following is a study of the trophic niche of Phrynops rufipes revealed by an investigation of stomach flushing and fecal samplings. We successfully stomach flushed all 31 adult turtles captured and collected feces from ten of the flushed turtles. Our results show that only an integrated approach using both techniques is able to provide a comprehensive picture of P. rufipes diet. Trichoptera larvae were the most eaten item in numeric terms and in frequency of occurrence, but shrimp contributed the greatest volume of invertebrates. The seeds of most kinds of palm trees common around streams in the area were eaten. Due to the limitations of stomach-flushing technique, palm fruits were underestimated, but they still contributed the highest volume of material flushed from the stomachs and found in the feces. Our findings alter the conclusions concerning the food habits of P. rufipes: it is an omnivore species that feeds in an opportunistic way on a greater quantity of benthonic macro-invertebrates and fishes than was evident from previous studies based on fecal sampling alone. [ABSTRACT FROM AUTHOR]

Leeches are one of the most commonly observed parasites of freshwater turtles. We used baited hoop traps to capture 433 turtles belonging to five species (Apalone spinifera, Chelydra serpentina, Chrysemys picta, Sternotherus odoratus, and Trachemys scripta) to determine the host (species, microclimate use, sex, reproductive stage, and body size) and environmental characteristics (month of capture, turtle abundance, vegetation, turbidity, pond size, and availability of basking structures) that affected leech parasitism in Illinois ponds. Leech prevalence on turtles varied significantly among turtle species, was highest on bottom-walkers and adults, and varied throughout the year. Leech intensity was highest on larger turtles and in turbid ponds. The results from this study display the importance of utilizing turtle assemblages for examining overall trends in host-parasite dynamics, demonstrate the influence of environmental characteristics on leech parasitism, and provide baseline data for future studies examining leech parasitism on turtles. [ABSTRACT FROM AUTHOR]

The body condition of an animal reflects its energetic state such that an animal in good condition has greater energy reserves than one that is in poor condition. Body condition in turn should be positively correlated with fitness because energetic reserves limit the amount of energy that can be allocated to reproduction. Using Spotted Turtles (Clemmys guttata) as a model system, and three years of field data from a South Carolina, USA population, we tested the prediction that reproductive output increases with maternal body condition. The effect of body condition on the reproductive output of female turtles was examined at three temporal scales (among clutches, among nesting seasons, and among females) using several variables including clutch frequency, clutch size, and multiple measures of egg size. We predicted that females in good condition will have a higher clutch frequency than those in poor condition; that females in good condition will have larger clutch sizes than those in poor condition; and that females in good condition will have larger eggs than those in poor condition. Among clutches and nesting seasons, we found no relationship between female body condition and reproductive output. Among females over the entirety of the three-year study, we found a positive relationship between body condition and clutch mass and egg size. In addition, females in poor condition and females in good condition both produced larger clutch sizes than females in intermediate condition. Our findings suggest that within a given reproductive bout and within a given reproductive season, energy reserves do not affect immediate reproductive investment. However, over the longer-term, females in good condition have greater reproductive output, which supports the idea of a bet-hedging life history strategy in turtles. [ABSTRACT FROM AUTHOR]

The ecologies of vertebrate species have been increasingly studied via stable isotope analyses of small quantities of body tissues. However, critical assumptions relating to the consistency in stable isotopic values in consumer tissues and their diet as well as the rate of incorporation of diet-derived stable isotopes into consumer tissues remain poorly validated for most taxa despite numerous stable isotope studies targeting natural systems. In this study, we measured stable carbon and nitrogen diet-tissue discrimination and elemental turnover in whole blood, red blood cells, blood plasma, brain, liver, pectoralis major muscle, pubioshiofemoralis internus muscle, stratum corneum (sc) dermis, and stratum germinativum (sg) dermis of Pond Sliders (Trachemys scripta) fed ad libitum on two isotopically distinct diets. Turtles were fed a soy-based control diet (32% protein, 3% lipids, 4% fiber), and after 146 d, a subset was switched to a fish meal-based experimental diet (44% protein, 24% lipids, 3% fiber). At the diet switch, diet-tissue isotopic equilibrium could not be confirmed by δ13C values for any tissue, but was established for δ15N values for all tissues except sc dermis and sg dermis (range = +1.9 to +3.8‰). An exponential-decay regression model and half-life calculation resulted in half-lives for N ranging from 35.6 d (blood plasma) to 52.5 d (liver). These represent the first published stable isotope turnover rates for reptiles and the first diet-tissue isotopic discrimination factors for freshwater turtles. The discrimination factors found here are similar to those established for soft-tissues among other vertebrate taxa; however, elemental nitrogen turnover rates in tissues of T. scripta are among the slowest established to date among vertebrate taxa. [ABSTRACT FROM AUTHOR]

We present body and clutch size information for two Gopher Tortoise (Gopherus polyphemus) populations, the southernmost populations for which such information is available. We combine these data with previous studies of 17 other populations to evaluate geographic variation in body and clutch size. Our study sites were Okeeheelee County Park, Palm Beach Co., Florida (OCP), and Archbold Biological Station, Highlands Co., Florida (ABS). Mean clutch sizes were 8.2 and 6.3 and mean adult female carapace lengths 308 mm and 274 mm at OCP and ABS, respectively. At OCP, clutch size showed a polynomial relationship with body size, with largest clutches at intermediate adult body sizes. This relationship may reflect senescence. Clutch sizes at ABS were not significantly associated with body size. Body size variation among populations showed a polynomial relationship to latitude, temperature, productivity, and seasonality; body sizes were smallest at intermediate values of all independent variables. Gopher Tortoises produce larger clutches in areas that are more southern, warmer, have greater productivity, and are less seasonal. Of environmental variables, clutch size variation is best explained by productivity. Future studies of other populations, particularly from the southern part of the range, are needed to evaluate the significance of the apparently unique clutch size-body size relationship observed at OCP, and to further clarify how and why body and clutch sizes vary throughout the range. [ABSTRACT FROM AUTHOR]

We quantified movements, spacing, and activity of Sonoran Mud Turtles (Kinosternon sonoriense) in interrupted mountain streams of southern Arizona over an 18-year period using capture-recapture sampling and radiotelemetry. Movement and activity patterns of turtles depended on water availability and varied by their sex and size. Although considered almost entirely aquatic in Arizona, mud turtles estimated terrestrially during periods of extreme drought. Mter the onset of summer rains, turtles increased the frequency with which they moved between pools and to nesting sites. Movements (average distance moved [AvD] ± SE) of all turtles were shorter during drought years (males = 26 ± 1.3 m, females = 19 ± 1.3 m) than non-drought years (males = 153 ± 1.2 m; females = 41 ± 1.2 m). Adult male turtles made longer movements (93 ± 1.2) and had longer home-range lengths (206 ± 1.2 m) than did adult females (AvD = 38 ± 1.2; home range = 40 ± 1.2 m). Younger adult females (carapace length [CL] 100-118 mm) made longer movements (52 ± 1.2 m) and had longer home ranges (80 ± 1.9 m) than did older females (>118 CL mm; AvD = 38 ± 1.2 m; home range = 26 ± 2.2 m). Males made movements >500 m more frequently (8%) than females (2%) and moved as far as 7.2 km as measured along drainage bottoms. Large turtles used pools exclusively, only rarely sharing pools with other large individuals of the same sex. Degradation and losses of interior wetlands in the southwestern U.S. have reduced the potential for long-distance movements of turtles among disjunct, remnant populations, which has consequences for conservation of turtles and other aquatic species in the region. [ABSTRACT FROM AUTHOR]

Most studies that have investigated the influence of hydric conditions during incubation on the size and quality of hatchling reptiles have used either vermiculite or sand as the incubation medium, and the applicability of data derived from eggs using one media type or the other to natural populations has had considerable debate. However, few studies have used soil from actual nesting areas as the incubation medium. In this study, I tested the influence of variation in substrate water content during incubation on the size of hatchling Snapping Turtles from southeastern Michigan using soil collected from actual Snapping Turtle nests. Eggs from six clutches were fully buried in sterilized soil that had been dried and then reconstituted to six different levels of hydration (3, 5, 7, 9, 11, and 13% gravimetric water content). Eggs in the driest soil (3%) had a slight net loss of mass over the course of incubation, whereas eggs in the wetter soils gained mass to varying degrees correlating positively with soil water content. Hatchling mass was significantly lower in the two driest soils than in the wetter soils. Carapace length was significantly shorter for hatchlings from the driest soil (3%) than for those from soils with 7% and 9% water contents, and significantly shorter for hatchlings from the wettest soil (13%) than for those from the 7, 9, and 11% water contents. Soil water contents measured adjacent to a single nest site over three consecutive field seasons ranged from 1.1 to 8.2%, with median water contents ≤ 5% in all three seasons. These findings support the hypothesis that normal variation in soil hydration can influence the size of hatchlings emerging from natural nests. The degree to which hatchling size varies with normal variation in soil water content, however, may have only minor impact on hatchling survivorship in light of other factors that could potentially influence hatchling survival in this species. [ABSTRACT FROM AUTHOR]

Turtles are in decline world-wide, and few studies have collected the long-term, age-specific demographic data needed to identify species-specific life history stages critical to population viability and conservation. Here I report estimates of birth and death rates, survivorship, and longevity of Spotted Turtles (Clemmys guttata) using modified logarithmic decay equations and 24 years of mark-recapture data collected from a population at the northern extreme of the species' range. The recruitment rate was more than twice the mortality rate. Spotted Turtle survivorship and longevity estimates are among the highest values reported for any animal species, and females are significantly more long-lived than males. Minimum annual adult female survivorship is 96.5%, maximum longevity is 110 years, and age at maturity is 12 years. Minimum male survivorship is 94.2%, maximum longevity is 65 years, and age at maturity is 11 years. This ongoing study is the longest-running on Spotted Turtles, yet insufficient age-specific data have been gathered to construct a life table, particularly because egg and hatchling survival rates remain unknown; future work should specifically focus on gathering such data. The results of the current study have important management implications when considering which life history stages to protect for maintenance of population viability of long-lived vertebrates. [ABSTRACT FROM AUTHOR]

Movement and activity patterns are important aspects of the ecology raid conservation of any organism. Among turtles, data on the behavioral ecology of hatchling stages are lacking. To increase our knowledge of hatchling turtles, I tracked 20 hatchling gopher tortoises (Gopherus polyphemus) for up to 335 days after hatching to determine movement patterns, refugia use, microhabitat use, and home range size. Consistent with other studies, hatchling gopher tortoises moved infrequently and over very short distances through their first winter, a period during which they are presumably receiving energy from yolk stores. With the onset of warm spring weather, hatchling tortoises began to move more, most likely to obtain energy after depleting yolk stores. Refugia included both burrows and pallets (short holes in the ground), which were surrounded by a high percentage of ground cover (81.4%) and tall (> 50 cm) vegetation. Home range size estimations depended heavily on the number of different locations recorded for each individual and varied from 0.0001--4.8 ha, depending on the method of calculation and longevity of the hatchling. Hatchlings moved infrequently, spent large amounts of time in burrows and under tall vegetation, anti moved short distances while changing refugia. However, these data represent some of the largest home range sizes reported for G. polyphemus to date, suggesting that dispersal and the hatchling life stage are important behavioral aspects that, if neglected, may result in underestimating spatial requirements necessary to support all ecological aspects of this declining, species. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms and patterns of how energy is allocated into the reproductive components of offspring size and number is central to life-history theory. We used X-ray photographs from a long-term mark recapture study of Kinosternon subrubrum, Sternotherus odoratus, and Pseudemys floridana to investigate hypotheses concerning variation in reproductive allocation due to constraint on egg size, within-female variability (within and among clutches), interannual environmental variation, multiple annual clutches, allocation of continuous resources into small integer numbers of offspring (fractional offspring-size problem), and age. Patterns of reproductive allocation varied markedly within and among species. Overall, egg size varied as a function of maternal body size and age, intra-annual clutch frequency, the fractional offspring size problem, and environmental variation. Clutch size varied with maternal body size, clutch frequency, and environmental variation. We examine how effectively the data support optimal-egg-size and phenotypic-plasticity models of reproductive allocation, and identify limitations of fundamental biological findings necessary to address the issues. [ABSTRACT FROM AUTHOR]

The Kemp's Ridley (Lepidochelys kempii) is one of the most endangered sea turtles in the world, and it possesses temperature-dependent sex determination (TSD). Sex ratios produced under TSD can vary widely and can affect the reproductive ecology of a population. Therefore, sex ratios produced from TSD are of ecological and conservation interest. The current study validated and utilized a testosterone radioimmunoassay (RIA) to examine the sex ratio of juvenile Kemp's Ridleys inhabiting the waters near Steinhatchee, Florida. Testosterone levels were measured in blood samples collected from juvenile Kemp's Ridleys captured over a three-year period. Results of this study indicate that a significant female bias (approximately 3.7:1) occurs in the aggregation of juvenile Kemp's Ridleys inhabiting the waters near Steinhatchee. [ABSTRACT FROM AUTHOR]

The relationship between egg size and composition (relative amounts of lipid, protein, and water) can play an important role in determining neonate size, quality, or the amount of post-hatching care observed in many reptiles. We evaluated the relationship among egg wet mass, non-polar lipid mass, water content, shell dry mass, and lean dry mass within and among seven clutches of the Diamondback Terrapin, Malaclemys terrapin, from Chesapeake Bay. Egg size varied considerably among clutches, but was relatively uniform within clutches. Non-polar lipid mass, lean dry mass, and water content correlated positively with egg wet mass indicating that larger eggs contain a proportionally greater amount of these components. There was no relationship between egg wet mass and shell dry mass. Clutches had similar, positive slopes but different intercepts in the relationships between lean dry mass and lipid mass and between water content and total dry mass. Thus, clutches differed in the relative proportions of resources but had similar allocation patterns of egg components. Our data cannot resolve whether these effects are due to differences in resource availability or differences in the physiological mechanisms involved in egg provisioning. [ABSTRACT FROM AUTHOR]

Flicker electroretinography (ERG) was used to examine the in situ photopic (cone-photoreceptor based) spectral sensitivities of Green and Loggerhead Sea Turtles. Both species were responsive to wavelengths from 440-700 mn, and both had peak sensitivity in the long wavelength portion of the spectrtun (∼580 nm). For Loggerhead Sea Turtles, no measurable responses were obtained below about 440 nm, whereas reliable signals were seen for Green Sea Turtles at wavelengths down to 400 nm. Both species exhibited significant declines in sensitivity below 500 mn. The overall shapes of the spectral sensitivity functions were similar for the two species. These results support previous findings that sea turtles have well-developed photopic visual systems. The characteristics of these spectral sensitivity functions indicate that both species possess multiple cone photopigment types, and these, in conjunction with the presence of colored oil droplets, strongly imply a capacity for color discrimination. Comparative evaluation suggests that these turtles have modified their visual pigments from those of their terrestrial relatives to better suit the ambient conditions present in the shallow water, submarine environments that they typically inhabit. [ABSTRACT FROM AUTHOR]

Information about animal movement patterns is critical to understanding their ecology, and such information is essential to the design of conservation plans for threatened species. Using radio telemetry, GPS, and ArcView GIS software, we examined seasonal activity, habitat use, movements, and home-range size of a southeastern population of Spotted Turtles (Clemrays guttata), a declining species. Data collected over three years revealed an annually repeated pattern of seasonal activity. Habitat use differed annually, seasonally, and between the sexes. Home ranges overlapped, and there was an area of concentrated overlap in early spring, indicating an aggregation of turtles, likely for breeding. Individuals showed annual fidelity to home-range areas. Home-range size (calculated using three methods) for males was smaller (∼5 ha) than that of gravid females (∼16 ha). Movement data did not fully support the reproductive strategies hypothesis. As predicted, gravid females moved greater distances than males during the nesting season. In contrast to the hypothesis, males did not more their greatest distances in spring at which time mating mainly occurs. That males did not make the predicted movements in spring can be explained by the fact that turtles aggregated at this time of year; thus, males do not need to travel to find mates. The current study is important because it provides information on the role of natural ("hurricane-tip-ups") and anthropogenic (powerline rights of way, clearcuts) disturbances in maintaining habitat heterogeneity and the early-successional vegetative communities preferred by Spotted Turtles. A set of management recommendations is presented. [ABSTRACT FROM AUTHOR]

Identifying sex of hatchling turtles is difficult because juveniles are not obviously externally dimorphic, and current techniques to identify sex are often logistically unfeasible for field studies. We demonstrate a widely applicable and inexpensive alternative to detect subtle but significant sexual dimorphism in hatchlings, using landmark-based geometric morphometric methods. With this approach, carapace landmarks were digitized from photographs of each hatchling, and shape variables were generated after variation in size, location and orientation were eliminated. These variables were then analyzed for sexual dimorphism, and used in discriminant function analysis to estimate sex of each hatchling. Using this approach on two species (Chrysemys picta and Podocnemis expansa), we found this method had high accuracy in assigning sex when compared with true sex (98% and 90%, respectively), and cross-validation revealed a correct classification rate of 85%. These correct classification rates were considerably higher than those found on the same species using linear distance measurements as data. We also explored two alternative statistical approaches for assessing sex (K-means clustering and multiple logistic regression) and found that these alternative approaches were accurate only 61% and 78% of the time, respectively, in C. picta and 69% and 77% of the time in P. expansa. These findings are similar to classification rates found for turtle species using approaches based on linear distance measurements. We also found that the observed sexual dimorphism differed between the two species. In P. expansa, males displayed relatively more expansion of the central region of the carapace relative to females, whereas in C. picta this pattern was reversed. We conclude that discriminant analysis of morphology quantified using geometric morphometrics provides researchers with a powerful tool to discriminate between male and female hatchling turtles. [ABSTRACT FROM AUTHOR]

We identify a fragmentary turtle specimen from the middle Miocene (MN 5) of Hambach, Germany, as the bridge peripheral of a carettochelyine turtle. This important find extends the fossil record of the group to the Neogene of Europe and calls into question the utility of fossil carettochelyids in identifying tropical climate zones. [ABSTRACT FROM AUTHOR]

The reptile immune response is performed by a well-developed immune system whose leukocytes have been characterized as lymphocytes, monocytes and granulocytes. A main characteristic of the reptile immune system is the effect of the seasonal cycle on its histology and function, as has been reported in the turtle Mauremys caspica. In the present study, we have assessed the presence of lymphocytes in the " main lymphoid tissues (blood, spleen, and thymus) searching for putative seasonal variations and sex-associated differences in lymphoid distribution. Our results show that lymphocytes are the most commonly observed leukocyte subpopulation in blood. The highest percentages of blood lymphocytes were obtained in spring. Lymphoid tissues showed higher proportions of lymphocytes in spring and summer. Finally, females showed higher lymphocyte proportions than males in the spleen during spring and in the thymus during summer. Summarizing, the lymphoid redistribution of M. caspica is affected by the seasonal cycle. The major proportion of lymphocytes was obtained in spring and summer; the seasonal periods when these turtles are more active, and the risk of infections is higher. [ABSTRACT FROM AUTHOR]

Gregarious behavior among oviparous female animals just prior to oviposition can be explained by several mechanisms, including a benefit to offspring survival. By clustering eggs together in one area, females may dilute the probability of egg predation. We tested the hypothesis that nest density influences egg survival in the Pig-Nosed Turtle (Carettochelys insculpta) along a river in northern Australia. Beaches with multiple nests were three times more likely to experience a predation event than beaches with single nests. However, the number of nests on a beach did not influence the probability of predation of individual nests, when considering either beaches with single versus groups of nests, or when comparing beaches with single nests, small groups of nests (n = 2-5), and large groups of nests (n = 6-8). Therefore, gregarious behavior of reproductive females during the nesting period did not dilute predation risk to nests. Four other hypotheses might explain the behavior: (1) nesting areas are limited; (2) nesting in groups dilutes predation risk to nesting females; (3) nesting in groups dilutes predation risk to hatchlings; and (4) social interactions in aggregations of nesting females provide additional information on nesting beaches/sites, reducing some cost associated with independent assessments of nesting beaches/sites. [ABSTRACT FROM AUTHOR]

We studied the reproductive and nesting ecology of the Yellow-Blotched Map Turtle (Graptemys flavimaculata) from 1993-1994 and from 1996-1997 on the Pascagoula River in southeastern Mississippi. This species has undergone a recent decline leading to its listing as Threatened under the U.S. Endangered Species Act. We found three distinctive features of the biology of this population: a relatively low reproductive frequency compared with most other map turtles (maximum of 1.16 clutches/female), a very high level of nest mortality caused by river flooding and fish crow predation (90% mortality in some years); and an unexpectedly high level of nesting in shaded areas along the riverbank, perhaps in response to human disturbance on and near sandbars. Our data suggest that, in the absence of extraordinarily high adult survival, this population will decline because of low recruitment. We suggest a series of specific strategies to reverse these declines, including better law enforcement to protect adult turtles, public education, and possibly, protection of nests on the nesting beaches. [ABSTRACT FROM AUTHOR]

The effect of predation by large non-gape-limited vertebrates on the survivorship and size distribution of larvae of four anuran species was assessed using two syntopic freshwater turtle species, Emys orbicularis and Mauremys leprosa. Predator species and predator sex within species were used as treatments in replicated, factorial experiments for predation trials on tadpoles of Bufo ealamita, Hyla mericlionalis, Rana perezi, and Pelobates cultripes. Tadpole consumption rates were significantly higher for the carnivorous E. orbicularis than for M. ieprosa. Rana perezi tadpoles were the least consumed, whereas R cultripes and H. meridionalis had the lowest survivorship rates, being relatively easier to catch than R. perezi. Significant size selection occured for larger tadpoles of R cultripes, whereas predation upon R. porezi tended to concentrate on the smaller size classes. The results point to an overall tendency of turtles to predate upon large tadpoles, yet the outcome of size selection by large vertebrates may depend on phenotypic traits that enhance the escape potential of tadoles. Mauremys leprosa had a high rejection rate of tadpoles, suggesting a higher sensitivity to unpalatability as compared to E. orbicularis, especially with relation to R. perezi. The results indicate that the effect of unpalatability as a predation deterrent may vary even among taxonomically close predator species. [ABSTRACT FROM AUTHOR]

Presents news briefs related to ichthyology and herpetology as of August 20, 2004. Web site created by the Morphological Informatics Group University of Missouri at Rolla; Poster illustrating the state turtles published by the Touchstone Energy Cooperatives of Kentucky; Conference on the biology of rattlesnakes.

Reports on the posters published by the Maine Department of Inland Fisheries and Wildlife illustrating the state's amphibians, turtles and reptiles as of September 2004. Number of posters published; Animals included in the posters.