We collected information to determine the status of Barbour's map turtle (Graptemys barbouri) in Florida by conducting standardized surveys of occupied watersheds in 2014–2015, including the Choctawhatchee, Chipola, Apalachicola, and Ochlockonee rivers. Single-pass basking surveys were used to determine the distribution and relative abundance of G. barbouri. Multiple-pass basking surveys and N-mixture modeling were used in sections of the Apalachicola and Ochlockonee rivers to estimate detectability and abundance of map turtles. Observed counts were compared with available information from previous surveys to make inferences about population change. A total of 5917 G. barbouri observations were recorded during single-pass surveys along 502 river kilometers (rkm) and we expanded the documented range by 76 rkm. Further, we used multiple-pass surveys to estimate 2079 G. barbouri along six 2-km sections (12 km total) of the Apalachicola River (173.3 turtles/rkm) and 292 G. barbouri along five 5-km sections (25 km total) of the Ochlockonee River (11.7 turtles/rkm). The present study is the most comprehensive distributional survey for G. barbouri in Florida to date. The species was documented for the first time in 2 counties and observed counts were consistently higher than in previous surveys. Overall, the Florida population appears secure with evidence of expansion in both the Choctawhatchee and Ochlockonee drainages.

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.

The impacts of human modifications of rivers and associated riverine fauna are well documented, especially following the construction of impoundments. In the Pearl River system of Mississippi and Louisiana, 2 endemic Graptemys species are found (G. oculifera; G. pearlensis), but little is known of their densities in urban segments near Jackson, Mississippi, even though both are species of conservation concern. I used spotting scopes and binoculars to complete replicated basking surveys for both Graptemys species during the summers of 2017 and 2018 in 5 equidistant segments of the Pearl River and nearby oxbow lakes. Basking densities for both species were generally higher in river segments upstream and downstream of Jackson compared to middle segments. Graptemys oculifera were found in greater densities than G. pearlensis in all segments (14–69-times higher). Graptemys oculifera was found in 4 of the 6 oxbow lakes surveyed, but mean densities decreased 10-fold compared with river segments; G. pearlensis was absent from all oxbow lakes. Densities for a generalist turtle species, Trachemys scripta, increased 35 times in oxbow vs. river habitats. The middle 3 survey segments (∼ 15.9 river kilometers) are inclusive of a proposed river impoundment project—the One Lake Project—for flood control and economic development. Estimates of direct and indirect impacts of this project are sizeable for G. oculifera (direct impact: 1684; indirect: 2129) while estimates for G. pearlensis are lower (direct: 88; indirect: 219). The One Lake Project would surely alter existing riverine processes and will favor generalist turtles such as T. scripta that prefer nonflowing lake settings at the expense of riverine Graptemys species. The One Lake Project would be a major setback to both Graptemys species in and around the project area and would negatively impact the recovery potential of both species.

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.

Northern map turtles (Graptemys geographica) are a species of conservation concern with a limited distribution in Pennsylvania. We examined nest site fidelity of G. geographica along the Juniata River at Mount Union, the largest reported nesting area in the commonwealth. Nesting habitat included a mitigation area bordering a highway, partitioned by a turtle exclusion fence, and an adjacent pile of coal tailings. A linear grid along the turtle fence allowed us to determine distances between nests of individual females. Our results indicate that female G. geographica at Mount Union exhibit nest site fidelity, as the frequency distribution of distances between nests of individual females was positively skewed, and distances between nests (both within and among seasons) were smaller than distances between randomly selected pairs of nests from different individuals. Females placed different clutches of eggs as close together as 0.30 m. Within-season (first and second clutch) internest distances were significantly smaller than internest distances among years, which increased over time. We also attached radio transmitters to a sample of adult females following nesting to determine the extent of riverine migrations, as long-distance nesting migrations are associated with fidelity to particular nesting sites. Following nesting, 2 females remained in the river near the Mount Union nesting habitat and 3 females moved downstream 4.3–5.6 km, yet all of the turtles returned to their previous nesting areas the following summer. Nest site fidelity can benefit map turtles if the habitat remains stable, results in high nest survivorship, and produces high-quality hatchlings, yet the behavior may be detrimental if it exposes turtles to significant risks such as road mortality or environmental contaminants. Our results indicate that maintaining long-term nesting habitat and ensuring suitable river quality at Mount Union may be essential for the conservation of G. geographica in central Pennsylvania.

Despite its biological importance in shaping both individual fitness and population structure, much remains to be learned about the hatchling emergence ecology of most freshwater turtles. Here, we provide some of the first details on these early life stages for the Ouachita map turtle (Graptemys ouachitensis) obtained during 2015–2017 along the lower Wisconsin River, Iowa County, Wisconsin, and integrate our results into related research within the genus Graptemys. Dedicated trail cameras over in situ turtle nests provided otherwise difficult to obtain observational data relevant to natural hatchling emergence without disturbing nests or hatchlings. In contrast to some earlier reports for Graptemys, hatchling emergence was mostly diurnal and synchronous, primarily in the morning soon after soil temperatures began to rise from overnight low values. Data suggest a temperature change model of cueing hatchling emergence, which may represent a local or regional adaptation to reduce nocturnal predation risks, mostly from raccoons (Procyon lotor), or may simply reflect default diurnal hatchling activity patterns when not affected by thermal constraints. Aside from predation, hatchlings on this small study site are affected by vegetative shading, leading to relatively long times to first emergence periods (mean, 82.3 d), low mean nest temperatures (25.9°C), and a likely male-biased sex ratio. These findings highlight the value of hatchling emergence studies in revealing important influences on population viability and in guiding appropriate habitat management in conservation efforts.

Despite its importance to individual fitness and population dynamics, the dispersal behaviors of most neonate freshwater turtles after nest emergence are poorly known. We studied the initial dispersal tendencies of neonate Ouachita map turtles (Graptemys ouachitensis) exiting natural nests during 2015–2017 along the Wisconsin River, Wisconsin. Overall, dispersal was nonrandom, and hatchlings largely oriented toward the nearest substantial vegetative cover, a woodland north of the nesting area. However, variation sometimes occurred in routes taken among hatchlings within a clutch. Directional changes within an individual's dispersal track, including route reversals, were also observed. As our work appears to be the first to use standalone trail cameras as a primary data-gathering tool for a hatchling dispersal study, it highlights the potential benefits and limitations of this technique for similar research.

In many freshwater turtle species, increasing adult female body size is accompanied by increases in both clutch size and egg size. Because clutch size and egg size represent competing sinks for the increasing abdominal space that can be devoted to reproductive potential as a female grows larger, both are hypoallometrically related to body size, i.e., each increases at less than the rate at which body size is increasing. I studied the reproductive allometry of 2 species of the map turtle and sawback genus (Emydidae: Graptemys) in syntopy in the Alabama River. Relative to congeners, Graptemys nigrinoda is a small-bodied species and Graptemys pulchra is a large-bodied species. In the study populations, adult female G. pulchra were on average 23% larger in plastron length and 125% larger in body mass and there was no overlap in size. Both species had positive but hypoallometric relationships of both clutch size and egg size with body size, a pattern reported for 3 congeners previously, thus further demonstrating the competing sinks of increases in both variables and refuting the optimal egg size hypothesis. For interspecific comparisons using analysis of covariance, there was no significant effect of species on clutch size after accounting for the effect of plastron length. The effect of species on egg width and width of the pelvic aperture was significant, with G. pulchra having relatively wider eggs and pelvic apertures, perhaps related to the more domed carapace and larger body sizes of their hatchlings. Compared with 3 congeners, the 2 Alabama River species had relatively small clutches of relatively large eggs. Latitudinal effects on reproductive output may be important in Graptemys, with more-northerly populations tending toward larger clutches of smaller eggs. There is a need to analyze more data from more populations with log-log analyses of reproductive allometry to confirm the trend. There is also a need to consider shape allometry in future analyses; in particular, the hypoallometry of both shell height and shell width relative to shell length.

The conservation of species at the periphery of their ranges has been gaining increased attention. The northern map turtle (Graptemys geographica) is a wide-ranging species that is considered globally stable. However, some states/provinces may have only peripheral populations of the species with either few existing populations or a small area occupied. In Mississippi, only a small portion of northeastern Mississippi occurs in the Tennessee River drainage, a drainage occupied by G. geographica, and range maps project that the species may occur in a small fraction of the state in Tishomingo County. However, no specimen or photographic vouchers had previously been collected for the species. We conducted canoe and visual point count surveys within creeks of the Tennessee River drainage to determine if G. geographica is present and, if so, to further assess the distribution and abundance of the species in northeastern Mississippi. We discovered the species in 2 confluent creeks in Tishomingo County, but only 1 appears to hold a viable population. The habitat of these creeks, including bedrock or gravel substrate, is similar to localities previously described for the species; the species was absent from areas surveyed dominated by clay- or sandy-bottomed creeks. Peripheral populations of a species are usually the first populations to exhibit declines, and it is therefore important to manage those populations accordingly and protect their genetic integrity. For these reasons, we suggest listing the species as critically imperiled (S1) and endangered in Mississippi. These designations would afford state protection to what is now likely Mississippi's rarest turtle species.

The movement of nonindigenous aquatic species into new river systems has the potential to negatively impact native species and/or their environments. The construction of the Tennessee-Tombigbee Waterway (TTW) in the 1970s and 1980s directly linked 2 evolutionarily distinct aquatic communities, and faunal exchange across the TTW has been documented in both fishes and freshwater mussels. However, to date there have been no recognized exchanges of the turtle fauna between the Tennessee and Tombigbee river systems. Herein we document the exchange of Ouachita map turtles (Graptemys ouachitensis), a native of the Tennessee River system, and Alabama map turtles (Graptemys pulchra), a native of the Tombigbee River system, each occurring outside its native ranges in the opposite river system likely via dispersal in the TTW. For G. ouachitensis, we observed a range displacement of ∼ 55 river kilometers (rkm) south from the nearest specimen records in the Tennessee River system into upper Bay Springs Lake of the Tombigbee River drainage. Graptemys pulchra had a range displacement northward of ∼ 137 rkm from the nearest specimen record in the Tombigbee River system to Pickwick Lake of the Tennessee River drainage. For the latter, it seems most parsimonious that G. pulchra historically occurred farther north than the specimen record suggests. Otherwise, individuals would have had to execute movements through and/or around 4 locks and dams, which seems less probable. We recommend that additional monitoring of nonnative turtles should be conducted to document existing range and potential range expansions (inclusive of Graptemys nigrinoda, blackknobbed sawback) while studies to assess genetic introgression among these closely related species are warranted.

Humans commonly move turtles and tortoises across geopolitical and geographic boundaries through food markets and the pet trade. One group commonly encountered in the pet trade is the genus Graptemys (map turtles and sawbacks). In the late 1980s, Graptemys pseudogeographica (false map turtle) was documented outside of its native range in the Pearl River near Jackson, Mississippi. Through replicated visual surveys in 2017 and 2018, we found that G. pseudogeographica persists in this location, but their densities were low (0.22/river km; 0.5% of all observations) compared with the 2 native Graptemys species. We evaluated the historical avenues for introduction via natural or human-mediated routes. Based on topographic profiles and historical hydrologic records, we strongly refute a prior hypothesis that G. pseudogeographica naturally colonized the Pearl from a neighboring drainage during the Easter Flood of 1979. Rather, we suggest that introduction via the release of unwanted pets is a more parsimonious conclusion. Because the lineage is shallowly diverged on an evolutionary scale, it seems possible that hybridization could occur between introduced G. pseudogeographica and Graptemys oculifera. Consequently, genetic introgression of the nonnative G. pseudogeographica genome is a possible threat to G. oculifera, a federally threatened species. This is a conservation concern to be further evaluated.

We used a 36-yr study of a turtle community in a northern Indiana lake to examine shell anomalies and temporal changes in their frequency in 3 species. The overall frequency of shell anomalies was 17% in painted turtles (Chrysemys picta), 11% in northern map turtles (Graptemys geographica), and 18% in red-eared sliders (Trachemys scripta elegans), and there were more anomalies on the carapace than on the plastron in 2 species (C. picta and G. geographica). The probability that an individual would have a shell anomaly was affected negatively by year of first capture and estimated year of hatching in C. picta and by carapace length at first capture in C. picta and T. s. elegans, although the relationships were weak (all r² ≤ 0.15). Thus, there was no suggestion of a systematic change in shell anomalies over time in the Dewart Lake turtle community.

Long-term data sets are critical in assessing populations of long-lived species such as turtles. The Urban Turtle Project was initiated in 2018 to begin building a long-term data set on the demography and ecology of the turtle populations in various urban waterways of Birmingham, Alabama. Another goal of the project is to increase public awareness of the state's impressive chelonian diversity by employing citizen scientists on semiannual sampling weekends. In its 2-yr existence, 52 participants volunteered over 200 hrs during 4 sampling weekends, with 16 volunteering for multiple weekends. Over 200 turtles of 10 species were sampled, with the majority of captures (n = 83) being Alabama map turtles (Graptemys pulchra), a historically understudied species. Collected demographic and reproductive data contribute to a better understanding of natural history of G. pulchra and how this and other species exist in an urban environment.

The high valuation of urban green spaces is obvious, given the lost economic opportunities their preservation requires. With more and more of the world's human population moving to urban areas, experiences with urban wildlife are becoming increasingly important for maintenance of people's connection to and concern for the natural world. Turtle watching provides an opportunity to connect urban residents with charismatic species that engender positive aesthetic responses from the public. In Erie, Pennsylvania, the Presque Isle Partnership is a nonprofit organization dedicated to enhancing visitor experiences at Presque Isle State Park. The park is a sandspit peninsula on Lake Erie that has abundant turtle populations in its sheltered bays and interior wetlands, particularly its populations of the common map turtle, Graptemys geographica. The common map turtles of Graveyard Pond have long been one of the park's signature wildlife spectacles. A basking aggregation that can exceed 100 turtles in late spring and early fall is enjoyed by visitors to a shoreline picnic area, canoeists, kayakers, and guests on the park's pontoon boat tours. In 2012, the Partnership funded construction of a handicapped-accessible turtle observation deck with fixed binocular viewfinders and informative signage. Total material cost for the project was $20,466 (∼ $22,922 in 2020 US dollars); labor for construction was donated by local industry. Since its construction, the observation deck has become a popular stop for park visitors. Similar projects would be suitable for many urban areas in the United States and many other countries with watchable turtle populations and would enhance urban residents' encounters with urban turtle populations.

Barbour's map turtle (Graptemys barbouri) is the species of map turtle with the highest degree of sexual dimorphism, with females attaining larger body sizes and having much greater head widths than males. Accordingly, females and males also feed on different riverine prey, with females historically feeding on native gastropods and bivalves and males predominantly feeding on soft-bodied macroinvertebrates. Here, we report on a diet shift in female Barbour's map turtle from native prey to an invasive mollusk, the Asian clam (Corbicula fluminea), in southwestern Georgia.

We observed the number of basking female Graptemys geographica (northern map turtles) at 4 basking sites before and after controlled motorboat disturbances using time-lapse cameras. In the 6 hrs following disturbance, the mean number of turtles basking at a site was 43.8% less than before the disturbance; this reduction in use of basking sites suggests that a single boat disturbance event can markedly affect the use of basking sites by female turtles for several hours. The behavioral and physiological impacts of such a shift in habitat use are unclear and should be the focus of future studies.

Nest-site fidelity has been well-documented in turtles, but it is not known how long this behavior can persist. Nesting areas used by 153 individually marked Mississippi map turtles (Graptemys pseudogeographica kohnii) during 2001–2003 were compared with those used in 2019. Only 2 of 100 turtles collected in 2019 were recaptures, but these turtles returned significantly closer to their original capture location than by chance. The 17-yr interval between successive captures represents the longest record of nest-site fidelity in a freshwater turtle.