Graptemys Flavimaculata Research Articles

Population Status of the Megacephalic Map Turtles Graptemys pearlensis and Graptemys gibbonsi and Recommendations Regarding Their Listing Under the US Endangered Species Act

The Pascagoula map turtle (Graptemys gibbonsi) and Pearl map turtle (Graptemys pearlensis) were first separated from the Alabama map turtle (Graptemys pulchra) in 1992 under the former name and subsequently recognized as 2 separate species in 2010. The possibility that they should be listed under the Endangered Species Act was raised 7 yrs after separation from G. pulchra, when basking surveys showed that at most sites they were considerably less abundant than 2 sympatric congeners listed as threatened: the Pearl River drainage's ringed sawback (Graptemys oculifera, listed in 1986) and the Pascagoula River drainage's yellow-blotched sawback (Graptemys flavimaculata, listed in 1991). Historical data also indicated that the sympatric species pairs may once have been more similar in abundance. Now, more than 2 decades later, G. gibbonsi and G. pearlensis are candidates for listing. From 2015 to 2018, we surveyed basking turtles in point counts and in jon boat and canoe surveys and conducted trapping at several sites to ascertain the status of the 2 candidate species. Data were also combined with similar data collected between 2006 and 2014. Despite their similarity morphologically and in their basic ecology, 3 important differences are pertinent to the question of whether the 2 candidate species should be federally protected. First, their river systems are geomorphically very different. The medium-size to large tributary streams that the 2 species inhabit are a considerably more prominent feature of the Pascagoula drainage than the Pearl drainage and may insulate populations from potential threats on the main stems. Second, G. gibbonsi inhabited 35% more stream reach, had 22% higher catch per unit effort, and were recorded at 44% higher numbers in point counts and 3% higher numbers in basking density surveys than G. pearlensis. Coarse-scale estimates of each species' global populations suggest that G. gibbonsi is ∼ 1.56 times as abundant as G. pearlensis overall. Third, the reasons for the listing of each species' sympatric sawback congener are very different: G. oculifera of the Pearl drainage was listed primarily due to existing and imminent but as-yet-unrealized habitat modification, while G. flavimaculata of the Pascagoula drainage was listed primarily due to perceived low populations, particularly in upper portions of the drainage, and concerns regarding water quality. We conclude that G. pearlensis warrants conservation protection via a listing as threatened, while G. gibbonsi should be listed either as threatened or as threatened by similarity of appearance. For G. gibbonsi, the former option would recognize a long-term historical decline in its relative abundance suggested by trapping data from the 1950s through 1970s, while the latter would recognize its less imperiled status and protect it from the pet trade while focusing recovery efforts on G. pearlensis.

Ecology of Riverine Turtle Communities in the Southern United States: Food Resource Use and Trophic Niche Dimensions

As part of an integrated study of the ecology of freshwater riverine turtle communities in the southern United States, we analyzed food resource partitioning in the turtle communities of the Cahaba, Chickasawhay, and Pearl rivers. We collected turtles with an array of unbaited fyke nets for periods of 10 d from 1 July to 13 August 1978 and 30 April to 4 August 1979, capturing 2707 turtles of 16 species in 2428 trap days. We successfully flushed the stomach contents from 729 turtles of the following species: Apalone mutica, Apalone spinifera, Graptemys flavimaculata, Graptemys gibbonsi, Graptemys nigrinoda, Graptemys oculifera, Graptemys pearlensis, Graptemys pulchra, Pseudemys concinna, Sternotherus carinatus, Sternotherus peltifer, and Trachemys scripta. We also caught 4 other species in low numbers: Chelydra serpentina, Graptemys pseudogeographica kohnii, Macrochelys temminckii, and Sternotherus odoratus. Stomach contents were identified and quantified by volume and percentage of occurrence for each species from each river. Food items were identified and placed in 6 categories: crustaceans, insects, mollusks, fish, plants, and unidentified. Pseudemys concinna was the most specialized feeder at all 3 sites, feeding almost exclusively on plants, followed by the wide-headed Graptemys and then narrow-headed Graptemys. Specialist species tended to show extensive niche overlap with any other species that consumed a large proportion of the specialists' preferred foods.

Spatial, Seasonal, and Sexual Variation in the Diet ofGraptemys flavimaculata, a Threatened Turtle of the Pascagoula River System, Mississippi, USA

The conservation of imperiled species often depends upon conserving their prey. Graptemys flavimaculata (Yellow-blotched Sawback) is an imperiled turtle endemic to the Pascagoula River system of Mississippi, USA. We investigated diet variability of G. flavimaculata relative to site geography, sex, seasons, and size. We captured individuals from May to October in 2007 and 2008 at two distant sites. One site is an inland freshwater tributary (Leaf River, LR) and the other site is coastal and tidally influenced (Pascagoula River, PR). Feces from males (n = 68) and females (n = 74) were collected and analyzed. Using the Index of Relative Importance (IRI; 0–100 scale, 100 = only item present in all samples), we found that G. flavimaculata are primarily sponge specialists for both males (IRILR = 85, IRIPR = 91) and females (IRILR = 84, IRIPR = 65). For both sexes, between-site differences were more varied than within-site differences; for the latter, prey items were typically similar for males and females at a single site, but importance varied. Seasonal comparisons suggest that both LR and PR females shifted diets towards mollusks during the spring and fall, possibly associated with increasing energy and calcium for reproduction. Based on the frequency of wood fragments in feces, submerged deadwood appears important for prey species, and therefore, managers should conserve deadwood along riverbanks (i.e., mature riparian corridors). If channel maintenance is needed, deadwood should be moved toward banks rather than removed to conserve structure for prey species colonization.

Intersexual allometry differences and ontogenetic shifts of coloration patterns in two aquatic turtles, Graptemys oculifera and Graptemys flavimaculata.

Coloration can play critical roles in a species' biology. The allometry of color patterns may be useful for elucidating the evolutionary mechanisms responsible for shaping the traits. We measured characteristics relating to eight aspects of color patterns from Graptemys oculifera and G. flavimaculata to investigate the allometric differences among male, female, and unsexed juvenile specimens. Additionally, we investigated ontogenetic shifts by incorporating the unsexed juveniles into the male and female datasets. In general, male color traits were isometric (i.e., color scaled with body size), while females and juvenile color traits were hypoallometric, growing in size more slowly than the increase in body size. When we included unsexed juveniles in our male and female datasets, our linear regression analyses found all relationships to be hypoallometric and our model selection analysis found support for nonlinear models describing the relationship between body size and color patterns, suggestive of an ontogenetic shift in coloration traits for both sexes at maturity. Although color is critical for many species' biology and therefore under strong selective pressure in many other species, our results are likely explained by an epiphenomenon related to the different selection pressures on body size and growth rates between juveniles and adults and less attributable to the evolution of color patterns themselves.

Conservation genetics of the yellow-blotched sawback Graptemys flavimaculata (Testudines: Emydidae)

Turtles within the genus Graptemys are increasingly becoming a group of conservation priority due to (1) the number of species endemic to single Gulf of Mexico rivers and (2) human alterations of riverine habitat. The yellow-blotched sawback (Graptemys flavimaculata) is a federally threatened species that is endemic to the Pascagoula River system of southeastern Mississippi, USA. Currently, there is nothing known about genetic variation and population structure in G. flavimaculata. We used microsatellite data to analyze population genetic structure, assess historical demography, and determine effective population size at six sites throughout the Pascagoula River system. Considerable genetic diversity was found within each site (mean allelic richness: 6.65–8.08) and two analyses found no evidence of genetic bottlenecks. All of the pairwise FST values, while low (average = 0.026), were significant, with most sites possessing one or more private alleles. Pairwise FST values with the Escatawpa River site were larger (0.030–0.047), which likely reflect its historical isolation. Genetic distance was correlated to geographic distance between sites, with the exception of the Escatawpa River site; a similar pattern was also found with estimates of recent rates of migration among sites. While an analysis of molecular variance indicated that most variation was partitioned within rather than among sites, STRUCTURE analysis strongly supported the recognition of two distinct groups (mainstem Pascagoula vs. Escatawpa), with the possibility of additional substructure within the mainstem Pascagoula.

Effects of human disturbance on the behavior and physiology of an imperiled freshwater turtle

The effect of human disturbance on wildlife is of increasing interest because of the growing use of wildlands by humans for recreation. Few studies have documented the effect of human disturbance on behavior and physiology simultaneously, with no studies existing for any turtle species. Turtles are one of the most endangered taxonomic groups and many are of conservation concern, including the yellow-blotched sawback (Graptemys flavimaculata), a freshwater turtle of the Pascagoula River system, Mississippi, USA. We studied G. flavimaculata individual- and population-level basking behavior, while also documenting the effects of human disturbance on basking behavior at recreationally disturbed and control sites. We also assessed the physiological response of turtles to human disturbance by measuring heterophil/lymphocyte levels (H:L; higher levels indicate increased stress) and shell condition of captured turtles at the 2 sites. At the individual level, disturbed turtles at the recreationally disturbed site basked for significantly shorter durations than undisturbed turtles at the same site and undisturbed turtles at the control site; disturbed turtles at the control site basked longer than all groups possibly because the few instances of disturbances all occurred during a time of year when basking durations were longest. At the population level, we detected significantly lesser basking percentages at the recreationally disturbed site relative to the control site, possibly because of natural differences among the sites (i.e., a more stable thermal environment) or because of the higher level of human disturbance. At the recreationally disturbed site, more disturbances occurred on weekend and weekend bordering days relative to weekdays, and larger and slower boats disturbed significantly greater percentages of basking turtles compared to smaller and faster watercraft. Further, turtles from the disturbed site had significantly higher H:L levels relative to the undisturbed site, and an index of shell condition was significantly poorer at the disturbed site. Boating records indicate that the impact of recreational boating at the disturbed site likely has grown over the last 22 years because of an increase in the number and size of boats using the river; this trend will likely continue unless restrictions are enacted by managers and/or state entities to limit the number and size of boats that access the river. © 2013 The Wildlife Society.

Seasonal Variation of Corticosterone Levels in Graptemys flavimaculata, an Imperiled Freshwater Turtle

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.

Basking Ecology of the Yellow-Blotched Sawback (Graptemys flavimaculata), an Imperiled Turtle Species of the Pascagoula River System, Mississippi, United States

Abstract Basking is an understudied aspect of turtle biology, especially considering how frequent and observable it is in some species. Researchers have suggested many physiological roles that basking likely fulfills in turtles. We documented seasonal basking behavior of the yellow-blotched sawback (Graptemys flavimaculata) on the Leaf River, a tributary of the Pascagoula River in southeastern Mississippi. We used binoculars and a spotting scope to determine G. flavimaculata individual- and population-level basking patterns throughout the main active months (April–October) and across the daily activity period; we also describe a new method to determine population basking percentage that may be useful for future aquatic turtle surveys. We found distinct differences in individual- and population-level basking behavior across months, sexes, and the daily activity period. We also documented differences in basking structures used between the sexes but found little correlation between population-level basking a...

Morphological and Molecular Reassessment of Graptemys oculifera and Graptemys flavimaculata (Testudines: Emydidae)

The turtle genus Graptemys consists of 15 recognized taxa, distinguished largely on the basis of pigmentation pattern (i.e., soft tissue and shell), head size, and shell morphology. However, phylogenetic studies have shown limited sequence divergence within the genus and between Graptemys oculifera and Graptemys flavimaculata relative to most other members of the Emydidae. Graptemys oculifera of the Pearl River drainage and G. flavimaculata of the Pascagoula River drainage have been recognized as species since 1890 and 1954, respectively. However, the description of G. flavimaculata was based on a limited number of morphological characters. Several of these characters overlap between G. flavimaculata and G. oculifera, and no attempt was made to test for significant morphological differentiation. In this study, we reevaluated the morphological and genetic distinctiveness of G. flavimaculata and G. oculifera with (1) multivariate statistical analyses of 44 morphological characters and (2) 1,560 bp of sequence data from two mitochondrial genes (control region and ND4). The morphological and molecular analyses produced incongruent results. The principal components analysis ordinations separated the two species along a pigmentation gradient with G. flavimaculata having more yellow pigmentation than G. oculifera. Likewise, clustering analyses separated the specimens into two distinct groups with little overlap between the species. Our mitochondrial data supported previous findings of limited genetic differentiation between the two species. However, the results of our morphological analyses, in conjunction with recently published nuclear gene sequence data, support the continued recognition of the two species.

Genetic and Morphological Variation Between Populations of the Pascagoula Map Turtle (Graptemys gibbonsi) in the Pearl and Pascagoula Rivers with Description of a New Species

Abstract Cryptic or undescribed species pose a major problem in conservation biology. Managing multiple unresolved taxa collectively as a single entity could precipitate the loss of unrecognized genetic variation and unique populations and, possibly, lead to extinction of undiscovered or unrecognized taxa. In contrast to other species in its clade, the Pascagoula map turtle (Graptemys gibbonsi), as currently recognized, is not confined to a single major river system (or a cluster formed by a major river and adjacent minor drainages) but occurs in two major river systems, the Pearl and Pascagoula Rivers. We analyzed G. gibbonsi samples from both rivers for the first time in a morphological and molecular assessment of the taxonomic status of this poorly studied species. We compared the extent of genetic differentiation (mitochondrial DNA; mtDNA) between G. gibbonsi populations with members within the pulchra clade and between Graptemys oculifera and Graptemys flavimaculata. We found significant carapace pat...

Reproductive parameters in female yellow-blotched map turtles ( Graptemys flavimaculata) from a historically contaminated site vs. a reference site

Graptemys flavimaculata, the yellow-blotched map turtle, is a long-lived, threatened, species, endemic to the Pascagoula River drainage in Mississippi. During the 1980s, one branch of the drainage (i.e. the Leaf River) was impacted by effluent from a wood pulp processing plant known to contain endocrine disrupters. A decade later, we examined seasonal reproductive parameters (i.e. monthly plasma estradiol-17β (E 2), testosterone (T), vitellogenin (VTG) and follicular development) in adult female turtles from historically polluted and reference sites in the drainage to determine if legacy exposure to pollution impacts reproduction . We found no seasonal patterns in E 2 or T and these patterns did not differ between sites. However, E 2 differed significantly among ovarian stages for the reference, but not pollutant exposed females. A significantly greater percentage of reference site females were able to produce a second clutch than females from the historically polluted site (50% and 17%). Additionally, there was a significant positive correlation between E 2 with VTG levels for reference, but not pollutant exposed females. Body and yolk tissue contaminant analysis indicated that exposure to pollutants is presently minimal and unlikely the cause of the reproductive differences observed between sites; instead, differences are potentially due to exposure history.

Comparison of the Effects of Dipotassium Ethylenediaminetetraacetic Acid and Lithium Heparin on Hematologic Values in Yellow-blotched Map Turtles, Graptemys flavimaculata

ABSTRACT The effects of dipotassium ethylenediaminetetraacetic acid (EDTA) and lithium heparin on hematologic values of yellow-blotched map turtles, Graptemys flavimaculata, were compared. Ten animals confiscated by the Department of Natural Resources, Georgia had blood drawn from the occipital sinus as part of a health evaluation. Length and width of red blood cells were compared between different treatment groups (EDTA, lithium heparin and fresh blood). A complete blood count and hemoparasite examination were performed on each anticoagulated sample. There were no significant differences in lengths between groups, but widths were significantly smaller (P<0.05) in anticoagulated blood smears than in fresh blood smears. Using a paired t test, EDTA and lithium heparin samples were significantly different (P<0.05) for packed cell volume percentage, plasma protein, white blood cell count, heterophils, eosinophils, monocytes, azurophils, and combined monocytes and azurophils counts. The data showed that EDTA i...

No place to nest or bask: Effects of human disturbance on the nesting and basking habits of yellow-blotched map turtles ( Graptemys flavimaculata)

Considerable recent attention has focused on how human disturbance alters the behaviour of imperiled taxa. Data on such impacts are common for waterfowl, marine mammals, and some large game animals. However, little is known about how human disturbances affect reptiles, perhaps because most reptiles are secretive and are not commonly seen by the public. We studied the impact of human disturbances on the nesting and basking behaviour of the yellow-blotched map turtle ( Graptemys flavimaculata) on the Pascagoula River in southeastern Mississippi, USA. We found that both nesting and basking behaviour of map turtles were altered by human recreational activities. Turtles attempting to nest commonly abandoned their attempts upon the approach of a boat and, prior to nesting, numerous individuals waited several hours near the beach without emerging. Basking turtles frequently dove into the water upon the approach of a boat and some did not return to bask. Anglers in small boats that remained in the vicinity of basking sites caused the most disturbances, whereas personal water crafts (jet skis) caused fewer disturbances. Our data suggest that interruption of nesting activities may have an especially severe impact on the viability of this population through changes in numbers of clutches females are able to lay and altering the microhabitat females select for their nests.

Reproductive and Nesting Ecology of the Yellow-Blotched Map Turtle, Graptemys flavimaculata: Implications for Conservation and Management

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.

Enteric Helminths of Graptemys flavimaculata Cagle, 1954, a Threatened Chelonian Species from the Pascagoula River in Mississippi, U.S.A.

The enteric helminth fauna of the threatened yellow-blotched sawback turtle, Graptemys flavimaculata Cagle, 1954, was examined for the first time. Seven specimens were collected from the Pascagoula River in Jackson, George, and Green counties, Mississippi, U.S.A. The turtles were necropsied for toxicology studies, and their intestinal tracts were salvaged for parasitic analysis. One acanthocephalan species, Neoechinorhynchus stunkardi; 5 trematode species, Telorchis corti, T. angustus, T. singularis, an unidentified pronocephalid, and Cotylaspsis cokeri; and 2 nematode species, Falcaustra procera, and Spiroxys sp., were found. No new species were encountered; however, G. flavimaculata is a new host record, and the Pascagoula River is a new location record for all 8 helminth species. Transmission of at least 3 of the 8 helminth species involves ingestion of a mollusc intermediate host by the turtle host, which is not unexpected given the molluscivorous diet of adult G. flavimaculata.

Comparison of reproductive parameters in male yellow-blotched map turtles ( Graptemys flavimaculata) from a historically contaminated site and a reference site

From May to September of 1998, we collected monthly plasma samples from male yellow-blotched map turtles captured at two sites in the Pascagoula River drainage, Mississippi. One site (Vancleave) has a documented history of pollution from industrial sources (principally 2,3,7,8-tetrachlorodibenzo- p-dioxin, TCDD). Fish consumption advisories at the Vancleave site were lifted in 1996 and current impacts appear minimal. However, the yellow-blotched map turtle, a federally protected species, continues to decline in numbers. To determine if endocrine disruption could be a factor in the low reproductive rates observed in Vancleave turtles, we examined levels of plasma testosterone ( T) and estradiol-17β (E 2) from males at this site and a second site (Leaksville), which has no known source of industrial pollution. Plasma was also tested for vitellogenin (VTG), which, in males, can be a biomarker of exposure to estrogenic contaminants. No males had detectable plasma VTG nor did mean monthly E 2 levels differ between sites. However, 10% of males from the historically polluted site were found to have high levels of E 2 (equivalent to levels found in females) and T was significantly lower for males captured at this site for 3 of 5 months. Our data suggest that the current impact of contaminants on reproduction in this population is limited. However, a portion of the population may have been affected developmentally, as represented by differences in reproductive parameters detected between sites.

Seasonal Variation in Reproductive Steroids of Male and Female Yellow-Blotched Map Turtles, Graptemys flavimaculata

From April to October of 1996 and 1997, we measured seasonal changes in plasma testosterone (T) in male and plasma T and estradiol-17β (E2) in female yellow-blotched map turtles, Graptemys flavimaculata, from the Pascagoula River, Mississippi. In 1996, plasma from females was analyzed for progesterone. In 1997, ovaries of adult females were ultrasound imaged to determine stages of follicular development. Males exhibited peak T levels in September and October of both years, indicating fall gonadal activity. Males also exhibited a low level spring peak in T during April. Female E2 levels increased significantly in May and June, the primary period of ovarian development. Females with preovulatory follicles did not have significantly higher E2 levels than females with medium- or small-sized follicles. When compared to other freshwater turtle species, peak levels of E2 were low. Testosterone levels did not follow a distinct yearly pattern in females. Progesterone levels were elevated in June when peak nesting was observed. Ultrasound and hormone data indicate that females lack ovarian development in the fall and produce on average only one clutch per year.

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and organochlorine pesticides in yellow-blotched map turtle from the Pascagoula River basin, Mississippi, USA.

Concentrations of polychlorinated-dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs), -biphenyls (PCBs), and organochlorine pesticides were measured in tissues of map turtles collected from two locations in the Pascagoula River drainage of Mississippi, USA. PCBs were most predominant among the organochlorines with a concentration of up to 99 ng/g, wet weight (580 ng/g, lipid weight) in livers. The greatest concentration of PCDDs/DFs of 1.1 pg/g, wet weight (15.76 pg/g, lipid weight) was found in the liver of a male turtle. The measured concentrations of organochlorines were less than those reported for turtles from the Great Lakes Basin and upper St. Lawrence River. PCBs contributed 90-99% of the total estimated 2, 3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs). Particularly, PCB congeners 105, 118, and 156 accounted for 68-80% of the estimated toxic potency of PCBs in turtles.

Home Range and Seasonal Movements of the Turtle Graptemys flavimaculata

Home Range and Seasonal Movements of the Turtle Graptemys flavimaculata