Pet distribution modelling: Untangling the invasive potential of Trachemys dorbigni (Emydidae) in the Americas

Human activities have been changing the global biogeographic patterns by the introductions of invasive species. For reptiles, the invasion rate increase of non-native species is remarkably related to the pet trade, especially for freshwater turtles. Here we estimated the invasive potential of the South American turtle Trachemys dorbigni in the Americas using a combination of climatic and human activity variables. We built species distribution models based on data from the native and invasive ranges, using the ensemble model from five different algorithms (GAM, MAXENT, BRT, RF and GBM). We compared the two models’ performance and predictions, one calibrated with only climatic variables (climate-driven), and the second also included a descriptive variable of human activity (climate plus human-driven). Suitable areas for T. dorbigni covered occurrence areas of its congeners and highly diversified ecoregions, such as the eastern USA, the islands of Central America, and the south eastern and eastern Brazilian coast. Our results indicate that human activities allow T. dorbigni to establish populations outside of its original climatic niche. Including human activity variables proved fundamental to refining the results to identify more susceptible areas to invasion and to allow the efficient targeting of prevention measures. Finally, we suggested a set of actions to prevent T. dorbigni becoming a highly impacting species in the areas identified as more prone to its invasion.

Transcending marine turtles: first report of hatching failure in eggs of Amazonian freshwater turtles with symptoms of the fungal emerging disease fusariosis

In the last decades fungal pathogens are causing devastating population declines across a broad range of taxa. A newly emerging fungal disease, sea turtle egg fusariosis, caused by members of the Fusarium solani species complex (FSSC), has been reported to be responsible for hatching failure in sea turtles around the world. However, this has not been reported in other non-marine turtle species. Herein we report high hatching failure from eggs symptomatic of fusariosis in the yellow-spotted Amazon river turtle ( Podocnemis unifilis), inhabiting a pristine environment in the Ecuadorian Amazon. We assessed hatching success from eggs symptomatic and asymptomatic of fusariosis ( n = 680 eggs), tested for Fusarium infection by PCR amplifying the TEF-1α gene (n= 68 turtle internal egg swab samples) and sequenced eight amplicons for screening of FSSC membership on an Illumina Miseq. Hatchability was 72% for asymptomatic eggs, whilst only 8% of symptomatic eggs hatched. Eight percent of asymptomatic and 58% of symptomatic eggs tested positive for Fusarium spp. and sequencing revealed that nine sequence variants from three asymptomatic and four symptomatic eggs corresponded to F. keratoplasticum, F. solani and F. falciforme, the three major FSSC pathogens already reported in sea turtle egg fusariosis. Our study therefore suggests that observed hatching failure of eggs showing symptoms of fusariosis is at least partially caused by Fusarium pathogens within FSSC in a freshwater turtle. This report highlights that fusariosis is more widespread among the Testudines order than previously reported and is not limited to sea environments, which is of particular conservation concern.

Dynamics of the global trade Asiatic Softshell Turtle (Amyda cartilaginea Boddaert 1770): Shifting trends in commerce and consequences for sustainability

Biodiverse countries such as Indonesia provide the exotic Asiatic Softshell Turtle (Amyda cartilaginea Boddaert 1770) for the wildlife trade. Deciding which trade model is detrimental to species survival in the wild can be a major challenge for Management Authorities (MA) in implementing CITES. The consequences for conservation, long-term use, and livelihoods are uncertain. The study used the CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) trade database. The collection of raw data is based on trade reports for the species of freshwater turtles (testudinidae) for the period 2011 to 2021, export countries from Indonesia, export destinations for all countries and sources of harvested turtles from the wild. This research aims to study the freshwater turtle trading trends over the decade, compare total quotas to actual harvest, and recognize how the precautionary principle is applied in harvesting A. cartilaginea. Harvesting and trading are following the quota regulated under the Indonesian government. However, conservation efforts were less emphasized, so it is feared that there will be a population decline and even extinction in the future, while the population in the wild cannot be ascertained. The larger the harvest quota set and the shorter the harvest period, the larger the natural population that must be available.

Not only pond sliders: freshwater turtles in the water bodies of the Milan northern urban area (Italy)

Freshwater turtles represent one of the most common pets released in urban water bodies. In Europe, after the ban on the import of Trachemys scripta, other non-native turtle species now dominate the legal pet trade. Some of these species have high invasive potential, such as the well-known slider turtle, but their diffusion outside their native range is poorly known. This work summarises presence data about non-native freshwater turtles, different from slider turtles T. scripta, into two urban parks located at the northern boundary of the Milan outskirts (Italy, Lombardy). Turtle detections were obtained merging field surveys conducted from 2014 to 2020, with sparse pictures taken by occasional observers. The situation depicted shows, in addition to the ubiquitous spread of slider turtle subspecies and hybrids in both parks, the frequent presence of other multiple genera such as Pseudemys and Graptemys. Isolated individuals of Apalone spinifera, Graptemys ouachitensis, Mauremys sinensis, Pelomedusa subrufa and Sternotherus carinatus were also found. I also detected one Emys orbicularis, probably escaped or released.

Impacts of dams on freshwater turtles: a global review to identify conservation solutions

Dams create many impacts on freshwater ecosystems and biodiversity. Freshwater turtles are at direct and indirect risk due to changes caused by damming including the loss of terrestrial and aquatic nesting and feeding habitats, changes to resource availability and reduced dispersal. We reviewed the global scientific literature that evaluated the impact of dams on freshwater turtles, and carried out additional searches of literature published in seventeen languages for studies evaluating actions to mitigate the impact of dams. The search produced 43 published articles documenting dam impacts on 29 freshwater turtle species from seven families (Chelidae, Chelydridae, Emydidae, Geoemydidae, Kinosternidae, Podocnemididae and Trionychidae) in 13 countries. More than a third of studies (41.9%, n = 18) focused on nine North American species of the Emydidae. Few studies were found from Europe and Asia and none from Africa. The number of studies, life-history stage studied and threat status differed significantly between temperate and tropical latitudes. Most studies were from temperate latitudes, where studies focused more on adults and less threatened species compared with tropical latitudes. Studies evaluated dam impacts as barriers and changes to water flow and quality, but no studies were found that assessed turtles and changes to land cover or mercury caused by dams. More than half of the studies (59%, n = 24) suggested actions to help mitigate dam impacts. Yet, only four studies on three temperate and one tropical species documented the effect of interventions (dam removal, flow management, artificial pond maintenance and community-based action). These findings demonstrate a lack of documented evidence evaluating dam impacts on freshwater turtles particularly in tropical regions. This lack of evidence reinforces the importance of strengthening and maintaining robust long-term studies of freshwater turtles needed to develop effective conservation actions for this group of vertebrates.

Nidoviruses in Reptiles: A Review

Since their discovery in 2014, reptile nidoviruses (also known as serpentoviruses) have emerged as significant pathogens worldwide. They are known for causing severe and often fatal respiratory disease in various captive snake species, especially pythons. Related viruses have been detected in other reptiles with and without respiratory disease, including captive and wild populations of lizards, and wild populations of freshwater turtles. There are many opportunities to better understand the viral diversity, species susceptibility, and clinical presentation in different species in this relatively new field of research. In captive snake collections, reptile nidoviruses can spread quickly and be associated with high morbidity and mortality, yet the potential disease risk to wild reptile populations remains largely unknown, despite reptile species declining on a global scale. Experimental studies or investigations of disease outbreaks in wild reptile populations are scarce, leaving the available literature limited mostly to exploring findings of naturally infected animals in captivity. Further studies into the pathogenesis of different reptile nidoviruses in a variety of reptile species is required to explore the complexity of disease and routes of transmission. This review focuses on the biology of these viruses, hosts and geographic distribution, clinical signs and pathology, laboratory diagnosis and management of reptile nidovirus infections to better understand nidovirus infections in reptiles.