Search Results (33)

Previous studies have consistently reported the detrimental impact of dam construction on natural populations of softshell turtles across East and Southeast Asia, with particularly severe effects on large-bodied species. The Wattle-necked Softshell Turtle (Palea steindachneri), a large-sized and Critically Endangered member of the family Trionychidae, remains poorly documented throughout much of its native range in Southeast Asia. In this study, we present new field data from the Đà River basin in northern Vietnam, encompassing areas both upstream and downstream of the Sơn La Dam. Data were obtained through a combination of direct field observations, camera trap monitoring, and semi-structured interviews with local fishers and traders. Two individuals of P. steindachneri—including a juvenile—were recorded, providing the first confirmed evidence of ongoing natural reproduction in the region. Additionally, we documented 102 individuals of Pelodiscus sp., encompassing all life stages and indicating a stable, reproducing local population. Despite overlapping in macrohabitat use along the river, the two species were spatially segregated, with a minimum interspecific distance of 8.2 km, suggesting broad sympatry without syntopy, potentially due to microhabitat partitioning. These findings underscore the persistence and likely reproductive viability of P. steindachneri in modified riverine systems affected by dams, and have broader conservation implications for other threatened taxa with similar ecologies, such as Rafetus swinhoei. Urgent conservation actions, including habitat protection, community-based monitoring, and strengthened regulation of the wildlife trade, are essential to ensure the survival of remaining wild populations. Full article

Rio Grande Cooters (Pseudemys gorzugi) occupy the Rio Grande watershed and have among the smallest ranges of all North American freshwater turtles. Anthropogenic dewatering is considered to have caused range contractions and population declines. We sought to facilitate management recommendations by determining the extent of movement and potential associations with extrinsic cues. We conducted a GPS-enabled telemetry study from August 2015 to May 2017 on the Devils River in Texas, USA. We included Capture–Mark–Recapture data from 2011, 2014, and 2015–2018 to determine population status in conjunction with movement ecology. Turtles showed increased movement as streamflow and water depth increased. Larger movements were also made mid-year, coincident with the peak nesting season. We speculate that seasonality and increases in streamflow facilitate switches from slower, localized movement to transiting modes. We observed individual heterogeneity in transitory movements. Such movements led us to maintain our population estimate of 726 to 1219 individuals is representative of the entire Devils River. The extent of movement in P. gorzugi has been previously underestimated and long-range movements could explain observed genetic structure. Future efforts to re-establish natural flow regimes in the Rio Grande basin could potentially be the most effective management approach for this range-restricted chelonian. Full article

Freshwater turtle species preservation relies on understanding their population dynamics and geographical distribution. Amur softshell turtles (ASTs [Pelodiscus maackii]) are poorly protected due to insufficient awareness and the population in Northeastern China has experienced a steep decline compared to previous years. This study aims to investigate the population density and structure of ASTs in the Jewellery Island area of the Ussuri River in Northeast China using continuous-time capture–recapture methods in closed populations. A three-month mark–recapture study was conducted in 2022, resulting in 35 juvenile captures, including 12 recaptures from 23 marked individuals. The estimated population size in the study area was 40.79 ± 9.75 (95% confidence interval, 95% CI = 27–65), translating to 0.663 ± 0.158 turtles/ha (95% CI = 0.44–1.06 individuals/ha). Approximately 35.4–85.2% of the estimated population was marked. Additionally, we explored the influence of environmental variables on turtle distribution by dividing the surveyed sites into seven sections based on their natural characteristics. The ASTs distribution inferred from trapping successes was considerably different among sections, with most turtles (91%) captured at the vegetated shoreline and in water channel 2. This research offers essential baseline data to support future assessments of ASTs population on a larger scale and to inform the development of conservation strategies. Full article

Culturally, chelonians are important sources of nutrition and income for rural and urban people in tropical rainforests, but urban trade can cause declines in wild populations. This study analyses the urban chelonian trade and its trends to better understand the impact on free-living populations in the Northern Peruvian Amazon. We studied the urban trade of wild chelonians by conducting 526 days of participant observation and structured questionnaires with the main chelonian vendors in the wet markets of Iquitos between 2006 and 2018. The trade of chelonians decreased by −161.6%, from 22,694 individuals in 2006/07 to 8657 individuals in 2017/18. Chelonoidis denticulatus was the species sold the most (86.3%), followed by Podocnemis unifilis (13.6%). Podocnemis expansa was only sold in 2006/07. River turtle sales increased in the dry season, while sales of Chelonoidis denticulatus decreased. Turtles were the most expensive meat sold in urban markets: 49.7% more expensive than the most frequently consumed fish, Prochilodus nigricans, and 48.4% more expensive than poultry. Turtles represented only 0.19% (SD 0.23) of the index of domestic meat and fish consumption per capita. River turtle eggs are sold by a different set of vendors, and in 2017/18, 570,229 eggs were traded in the market of Belén in Iquitos, equivalent to an approximate lay of 10,418 P. unifilis and 1178 P. expansa females. The high magnitude of the trade of river turtle eggs together with the reduction in their meat trade suggests a prioritization of egg sales, which should improve the conservation of adults, since meat sales can be detrimental to chelonian populations. Full article

Bellinger River virus (BRV) is a serpentovirus (nidovirus) that was likely responsible for the catastrophic mortality of the Australian freshwater turtle Myuchelys georgesi in February 2015. From November 2015 to November 2020, swabs were collected from turtles during repeated river surveys to estimate the prevalence of BRV RNA, identify risk factors associated with BRV infection, and refine sample collection. BRV RNA prevalence at first capture was significantly higher in M. georgesi (10.8%) than in a coexisting turtle, Emydura macquarii (1.0%). For M. georgesi, various risk factors were identified depending on the analysis method, but a positive BRV result was consistently associated with a larger body size. All turtles were asymptomatic when sampled and conjunctival swabs were inferred to be optimal for ongoing monitoring. Although the absence of disease and recent BRV detections suggests a reduced ongoing threat, the potential for the virus to persist in an endemic focus or resurge in cyclical epidemics cannot be excluded. Therefore, BRV is an ongoing potential threat to the conservation of M. georgesi, and strict adherence to biosecurity principles is essential to minimise the risk of reintroduction or spread of BRV or other pathogens. Full article

Comprehensively understanding the spatial ecology and habitat preferences of endangered species is essential for population restoration and conservation. We investigated the home range and movement of the endangered Amur soft-shell turtle (Pelodiscus maackii) in the Ussuri River, Heilongjiang Province, Northeastern China. The study involved tracking 19 Amur soft-shell turtles from late June to mid-October, 2022, resulting in complete and partial home range size data for eight subadults and two adults, respectively. The primary analysis focused on eight subadults, and the models that best described daily movement were identified. We also explored the potential factors influencing home range size. The mean movement rate ranged from 39.18 ± 20.04 m/day to 72.45 ± 29.36 m/day and was positively correlated with the linear home range and water temperature. The most enlightening estimation of home range was derived from a 95% kernel density estimate, utilizing likelihood cross-validation smoothing while adhering to constraints delineated by the river boundaries. The average size of the home range was determined to be 1.02 hectares and displayed no correlation with body size. Subadults tended to establish well-defined home ranges over time, whereas defining home ranges for adults proved challenging. This research addresses a gap regarding the ecology of the Amur soft-shell turtle and provides a foundation for future conservation plans. Full article

Researchers recognize the silent, negative and deleterious effects caused by mercury pollution in gold mining areas. Freshwater turtles are culturally part of the diet of riverside populations in the Amazon region and this area presents mercury (Hg) pollution issues mainly due to gold mining activities. Thus, this research aimed to evaluate the total mercury (THg) content in the different organs of Amazonian giant river turtle (Podocnemis expansa) and carry out a human health risk assessment associated with the consumption of these animals. This study was conducted in the Vila Balbina, municipality of Presidente Figueiredo, state of Amazonas, Brazil. Skin (n = 28), muscle (n = 19) and brain (n = 2) samples were analyzed by Atomic Absorption Spectrometry (TDA-AAS) and a DMA-80™ mercury analyzer was used for the total mercury determinations. The average values found for THg in the skin, muscle and brain samples were, respectively, 0.1045 mg·kg⁻¹, 0.1092 mg·kg⁻¹ and 0.0601 mg·kg⁻¹. Thus, THg was observed even though the P. expansa were kept in captivity, possibly due to previous contamination by air, water and food. The Hazard Quotient (HQ) was calculated considering a 9.07 g·day⁻¹ intake dose of P. expansa and the consumption of turtles once a week showed an HQ = 2.45, which may cause long-term injuries to human health. Although the muscle concentrations were below the maximum limit established by the World Health Organization (WHO) and Brazilian regulatory agencies, it is important to evaluate consumption factors such as amount ingested, frequency and animal gender, which may cause a potential risk to regular consumers due to mercury bioaccumulation. The WHO may consider various aspects in order to warn the Amazon population about the severity and silent hazard of this metal, especially due to the importance of this matrix in the region. This region urgently needs government actions to inhibit clandestine mining and to prevent future serious, chronic health problems of the entire population. Full article

The low cost of production and the widespread use of plastics has brought about a problem that is difficult to measure; microplastics are considered emerging pollutants because their presence can pose a risk to the environment. This study focuses on the characterization of microplastics (MPs) in the nesting area of green (Chelonia mydas) and Kemp’s ridley (Lepidochelys kempii) sea turtles, on the coastal municipalities of Nautla and Vega de Alatorre, Veracruz, Mexico. Five beaches along 15.5 km of coastline were analyzed and samples were taken in the intertidal zone. In this work, only microplastics in sizes from one to five mm were analyzed. A characterization of the potential sources of microplastics at the basin level was carried out and 94% of the samples analyzed presented MPs, the greatest amount was at site Playa Navarro (B32) (1.2 Item/kg dw), and in the high tide zone (4.86 ± 2.79 Item/kg dw). The predominant color of the MPs was white (42%), the most representative form were fragments (31%), while most of the MPs presented sizes of 4–5 mm (35%) followed by 1–2 mm (34%). The chemical composition of most of the MPs was polyethylene (55%). Regarding the sources of the MPs generation, livestock, agriculture, fishing, tourism, wastewater discharges, urban solid waste and, to a lesser extent, the plastic industry were identified. The mobilization factors of the MPs turned out to be the Colipa and Misantla rivers with runoff from the basin, wind, waves and marine currents. Full article

In semi-distributed hydrologic models, it is difficult to account for the impacts of wetlands on hydrologic processes, as they are based on lumped, subbasin-scale wetland concepts. It is a challenge to incorporate the influences of individual small wetlands into watershed-scale models by using lumped parameterization. The objective of this study was to improve watershed-scale hydrologic modeling by taking into account real wetland features during the wetland parameterization. To achieve this objective, a joint modeling framework was proposed to couple a surface delineation algorithm with a semi-distributed hydrologic model and then applied to the Upper Turtle River watershed in North Dakota, USA. The delineation algorithm identified the topographic properties of wetlands, which were further utilized for wetland parameterization. A nonlinear area–storage relationship was determined and used in the estimation of the wetland-related parameters. The results demonstrated that the new joint modeling approach effectively avoided misestimating the wetland-related parameters by accounting for real topographic characteristics (e.g., storage, ponding area, and contributing area) of identified wetlands and their influences, and provided improved modeling of the hydrologic processes in such a wetland-dominated watershed. Full article

Citizen science is emerging as a powerful tool for the early detection of biological invasions. The exotic pet trade has been deemed as the most significant cause of establishment for reptiles, and among them, turtles have the highest number of introduction events. In Europe, at least 13 species of alien freshwater turtles have been recorded in the wild. In Greece, only two species of alien turtles have been reported, namely the American pond slider Trachemys scripta and the Florida cooter Pseudemys floridana. In this study, we provide an updated checklist of the alien freshwater turtles recorded in Greece, using citizen science, personal observations, and literature. Our results provide the first records for the country of five species, namely the Florida red-bellied cooter Pseudemys nelsoni, the Eastern river cooter Pseudemys concinna, the Chinese stripe-necked turtle Mauremys sinensis, the Chinese soft-shelled turtle Pelodiscus sinensis, and the Common snapping turtle Chelydra serpentina and new localities for T. scripta. Similar to the myth of the Lernaean Hydra (i.e., for every head chopped off, more would regrow), the pet turtle trade has been proven to have multiple heads. Full article

Natal philopatry—the return of an animal to its place of birth to reproduce—can shape population genetics and link essential habitats across generations, yet examples from long-term mark-recapture studies are rare. In this study, we observed 136 nests of Northern Map Turtles at Mount Union, Pennsylvania, between 2000 and 2008 and then individually marked and released 691 hatchling turtles into the Juniata River. During a recent six-year period (from 2017 to 2022), 46 of the hatchling-marked turtles (6.7%) returned to Mount Union as adult females to nest. The ages of these turtles ranged from 11–22 years at first recapture, and their mean age was 17 years. Forty-one hatchling-marked females came from observed nests with known mothers, and remarkably, just four (of 52) mothers produced over half of the returning females. The minimum ages of the oldest female turtles were estimated at 39 years, with reproductive lifetimes of at least 23 years. Our results indicate that a few long-lived Super Moms have made extraordinary contributions to hatchling recruitment and population viability of Northern Map Turtles of the Juniata River. The timing of release also had a significant influence on the probability of a turtle returning, with hatchlings released in May returning at a higher rate than those released earlier in the spring. In addition, morphological characteristics of hatchling-marked females suggest that factors causing shell shape abnormalities in adult turtles have not abated over the past two decades as previously theorized and likely involve exposure of juveniles to contaminants in the Juniata River rather than any maternal influence. Full article

Effective conservation of endangered species relies on the characterization of habitat use and tracking of long-term population trends, which can be especially challenging for marine species that migrate long distances and utilize a diversity of habitats throughout their lives. Since 2012, citizen science volunteers at the Aquarium of the Pacific in Long Beach, California, have been monitoring an urban population of East Pacific green sea turtles (Chelonia mydas) that resides near the mouth of the San Gabriel River (SGR) in Southern California, USA, in order to gain insights about how the population uses this area. Here, we collate and analyze nine years of citizen science data, including observed sightings collected across 10 observation stations. Our results confirm that green sea turtles are frequently present around warm water effluent from power plants, similar to research results reported for other locations in the eastern Pacific Ocean. Importantly, observational data also show notable green sea turtle activity around the outfalls for a small wetland habitat bordering the SGR, highlighting the importance of wetland ecosystems as a key habitat and foraging area for this threatened population. Finally, our results showcase the benefits of using citizen science to monitor sea turtle populations in easily accessible nearshore habitats. Full article

Environmental contaminants with chemical origins, such as organochlorine pesticides (OCPs) have major impacts on the health of marine animals, including sea turtles, due to the bioaccumulation of those substances by transference throughout the food chain. The effects of environmental pollution on the health of marine turtles are very important for management strategies and conservation. During recent decades, the south Gulf of Mexico and the Yucatan Peninsula have suffered from increasingly frequent disturbances from continental landmasses, river systems, urban wastewater runoff, port areas, tourism, industrial activities, pesticides from agricultural use, and other pollutants, such as metals, persistent organic pollutants (POPs) and hydrocarbons (from the oil industry activities), which contaminate water and sediments and worsen the environmental quality of the marine ecosystem in this region. In this study, we assessed the concentrations of OCPs in the blood and eggs of 60 hawksbill turtles (Eretmochelys imbricata) nesting at the Punta Xen turtle camp, and their effects on the nesting population’s reproductive performance: specifically, maternal transfer and embryonic development were analyzed. Hematologic characteristics, including packed cell volume, white blood cell count, red blood cell count, and haemoglobin levels, and plasma chemistry values, including creatinine, blood urea nitrogen, uric acid, triglyceride, total cholesterol and glucose, were also measured. The general health of the turtles in this study, as well as their levels of urea, serum creatinine, glucose, uric, acid, cholesterol, and triglyceride, fell within normal ranges and was similar to other normal values, which could indicate the turtles’ good energy levels and body conditions for nest-building activity, with all of the turtles able to successfully come ashore to nest. All the same, the obtained results also indicate that OCPs affect the nesting and reproductive performance of the hawksbill turtles, as well as their fertility and the development of the population of eggs and reproductive performance, specifically in terms of maternal transference and embryonic development. There were significant differences in the concentrations of OCPs (ΣHCHs and ΣDienes) between maternal blood and eggs, indicating that these chemicals are transferred from nesting females to eggs and, ultimately, to hatchlings. OCPs may, therefore, have an effect on the health and reproductive performance of hawksbill turtles, both in terms of their fertility and egg development. Conservation strategies need to be species-specific, due to differences in feeding, and address the reasons for any decline, focusing on regional assessments. Thus, accurate and comparable monitoring data are necessary, which requires the standardization of monitoring protocols. Full article

According to the IUCN, Southeast Asia is the area of the world with the highest number of threatened turtle species. The current status of chelonians is particularly catastrophic in Vietnam. However, there is still a lack of field data to unambiguously support this fact for a few species. To better understand the freshwater turtle diversity and eventually undertake efficient conservation actions, we conducted surveys with local fishers using standardized questionnaires in two independent river systems in northern Vietnam. A total of 112 questionnaires were administered to as many fishers in April and October 2022. We directly observed four sympatric freshwater species (Pelodiscus sinensis, Palea steindachneri, Mauremys sinensis and Sacalia quadriocellata) in Lao Cai and Yen Bai provinces, and two species (Pelodiscus sinensis and Palea steindachneri) in Bac Giang, Hai Duong, Thai Binh, and Hung Yen provinces. Based on the interviews, we added as possible the presence of two other species (Rafetus swinhoei and Pelochelys cantorii) in each of the two study areas. Moreover, we recorded for the first time in Vietnam, two wild individuals of an invasive alien species, the Common snapping turtle (Chelydra serpentina), confirming that the distribution and ecology of turtle species in Vietnam is poorly understood. Furthermore, recent photos (year 2019) of a 38 kg softshell turtle, possibly attributable to Rafetus swinhoei, were recorded from a restaurant in the area. In conclusion, interviews with local fishers have been found to be useful for exploring the likely presence and the local distribution of the various turtle species. Full article

In this study, we investigated the avian diversity and threatening factors in five peri-urban sites around Fez city (Morocco) for 2 years (2018–2019). The study hosted 131 avian species, including 64.88% breeding species, 19.84% migrant winterers, and 11.45% migrant breeders. Five species of conservation concern such as the vulnerable European turtle dove and the European goldfinch, the near-threatened ferruginous duck and bar-tailed godwit, and the endangered white-headed duck were recorded. Most bird species were recorded at the Oued Fez River (26.89%) and the El Mehraz dam (25%), followed by the El Gaada dam (17.4%), the Ain Bida garbage dump (15.5%), and the Ain Chkef Forest (15.18%). About 44.44% of the breeding species were found at Oued Fez, along with 33.33% at the El Mehraz dam, while El Gâada, Ain Chkef, and Ain Bida hosted only 7.40% of species. An important breeding population of the endangered white-headed duck was recorded at El Mehraz and Oued Fez. The extension of farmlands, urbanization, touristic activities, and drought constitute the most menacing factors for the avian diversity and their habitats in Fez. Full article