Tag: turtles

North American turtles establish succcessful populations in Germany, possibly threathening ecosystems

For the first time, self-sustaining populations of three non-native species of turtles were identified in south-western Germany by researchers at the University of Freiburg

For the first time, self-sustaining populations of three non-native species of turtles were identified in south-western Germany by researchers at the University of Freiburg

Original text published by the University of Freiburg

Three species of turtles native to North America have been successfully reproducing in the wild in Germany, report for the first time environmental researcher Benno Tietz and biologist Dr. Johannes Penner of the University of Freiburg, along with Dr. Melita Vamberger of the Senckenberg Natural History Collection in Dresden.

Their results were published in the open-access scientific journal NeoBiota.

The scientists examined a total of nearly 200 animals living in the wild in lakes in Freiburg and Kehl. Their findings suggest that the turtles have established themselves in a new habitat, where they could become a threat to the local ecosystem.

For two species, this is the first evidence of independent reproduction outside of their natural reproductive range. For the third species, this is the northernmost evidence of its presence up to now,

says Penner.
The false map turtle (Graptemys pseudogeographica) enjoys the sun’s warmth. Photo: Johannes Penner.

Turtles released into the wild

Invasive species do a great deal of economic damage world-wide. They also contribute to advancing global species extinctions.

Alien reptiles regularly make their way into the wild in Germany. Most often, this is because they have been released by pet owners.

Large numbers of North American pond sliders (Trachemys scripta) were imported into the European Union (EU) in the 1980s and 1990s as house pets. In 1997, their import into the EU was banned. By 2016, the sale of specimens born here was also made illegal.  Since then, pet shops have replaced them with other freshwater turtles, such as the river cooter (Pseudemys concinna) and the false map turtle (Graptemys pseudogeographica).

Genetic analyses of specimens of all three species in a range of ages have now demonstrated that they are reproducing independently in local waters. 

What’s surprising is that the invasive species have established themselves so far north. In Europe, successful reproduction and self-maintaining populations of Trachemys scripta were only known in the Mediterranean regions and the continental climate zone of Slovenia,

explains Benno Tietz.

Until recently, it had been assumed the turtles being examined couldn’t reproduce in Central Europe due to the colder climate. Especially the false map turtle is actually quite sensitive to the cold,

he says.
A North American pond slider (Trachemys scripta) resting on a lily pad. Photo: Johannes Penner.

Consequences for local species unclear

The invasive turtles could become a problem for indigenous species.

The European pond turtle (Emys orbicularis), for example, is now only present in Germany in parts of Brandenburg.

In an experimental setup, the European pond turtle showed weight loss and an increased death rate when being kept together with Trachemys scripta,

reports Penner.

Penner says that could be caused by the larger, alien species forcing the smaller local turtles from places where they sun themselves, leading the local turtles to have  problems with thermoregulation. Or perhaps the competition led to them having greater challenges when seeking food. 

Beyond that, aquatic turtles could be hosts for viruses and parasites, leading them to play a role in the spread of diseases. This could potentially have a damaging influence on other parts of the ecosystem, including amphibians, fish, or aquatic plants.

On the other hand, in their study, the researchers consider the alien species could assume functions in damaged ecosystems that would otherwise go unreplaced.

Vamberger says these questions urgently need to be explored further.

We need to raise public awareness that people should not release – no matter what kind of species – any animals into the wild in future.”

she insists.
A river cooter (Pseudemys concinna) lets itself drift in the water. Photo: Johannes Penner.
Meet the research team:

Dr. Johannes Penner was the scientific coordinator of the research training group “Conservation of Forest Biodiversity in Multiple-Use Landscapes of Central Europe” (ConFoBi) and a lecturer for the Chair of Wildlife Ecology and Management of the University of Freiburg. Currently, he is a curator at the NGO “Frogs and Friends” and a guest researcher in wild animal ecology.

Benno Tietz has completed a Master’s degree in Environmental Sciences at the University of Freiburg. His thesis – finished in the Winter Semester of 2020/2021 – investigated alien turtles. Currently, he is a research assistant at the Freiburg Institute of Applied Animal Ecology.

Dr. Melita Vamberger is a researcher at the Senckenberg Natural History Collection in Dresden.

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The study was supported by the Hans Schimenz Fund of the German Society for Herpetology and Terrarium Science (DGHT) as well as the Academic Society of Freiburg.

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Research paper:

Tietz B, Penner J, Vamberger M (2023) Chelonian challenge: three alien species from North America are moving their reproductive boundaries in Central Europe. NeoBiota 82: 1-21. https://doi.org/10.3897/neobiota.82.87264

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Wildlife trade threats: The importance of genetic data in saving an endangered species

In a new study, published in the scientific journal Nature Conservation, a research team analyses the genetic diversity of the endangered Four-eyed turtle, a species that has fallen victim to the growing wildlife trade in Vietnam. Having identified several distinct lineages in field-collected and local trade samples, the scientists warn that confiscated animals must not be released back into the wild before they have their origin traced back to the locality they have been captured.

In Southeast Asia, wildlife trade is running rampant, and Vietnam plays a key role in combating wildlife trafficking.

Since the country opened its market to China in the late 1980s, a huge amount of wildlife and its products has been transported across the border every year. Species have also been exported to other Asian countries, Europe and the USA. Furthermore, in recent years, Vietnam has also supported the transit of pangolin scales and other wildlife products from across Asia and even as far as Africa all the way to China and other destinations.

Additionally, in line with the expanding wealthy middle class, consumption of wildlife and its products has risen dramatically in Vietnam. As a consequence, the country takes on all three major roles in the international wildlife trade: export, transit and consumption.

Four-eyed turtle captured in Pu Mat National Park, central Vietnam
Credit: Asian Turtle Program
License: CC-BY 4.0

Freshwater turtles and tortoises make up a large part of the international trade between Vietnam and China and the domestic trade within Vietnam. Meanwhile, due to the increasing use of social networks, wildlife trade is shifting to online-based platforms, thereby further facilitating access to threatened species. Consequently, the Vietnamese pond turtle and the Swinhoe’s softshell turtle, for example, are already on the brink of extinction. Despite the repeated recent survey efforts of conservation biologists, no viable populations of their species have been found.

One of the effective approaches to the conservation of the most endangered species is to have confiscated animals released back into the wild, following the necessary treatment and quarantine, or transferring them to conservation breeding programmes. However, in either of the cases, it is necessary to know about the origin of the animals, because the release of individuals at sites they are not naturally adapted to, or at localities inhabited by populations of incompatible genetic makeup can have negative effects both on the gene pool and ecosystem health.

In the present research article, published in the peer-reviewed open-access scientific journal Nature Conservation, turtle conservationist and molecular biologist Dr. Minh D. Le of Vietnam National University (Hanoi) and the American Museum of Natural History (New York), in collaboration with the Cologne Zoo (Germany) and the Asian Turtle Program – Indo-Myanmar Conservation (Hanoi), the Institute of Ecology and Biological Resources (Hanoi) and Hanoi Procuratorate University (Hanoi), studies the geographic distribution of genetic diversity of the endangered Four-eyed turtle (Sacalia quadriocellata). The species, whose common name relates to the four eye-resembling spots, located on the back of its head, has traditionally been neglected by scientific and conservation efforts.

Having analysed field-collected and local trade samples along with confiscated animals, the researchers concluded that there is a significant number of genetically distinct lineages distributed in Vietnam and China, and that local trade samples could provide key data for resolving the genetic patterns of the species. They remind that Four-eyed turtles are getting more and more difficult to find in the wild.

Two four-eyed turtles captured in Pu Mat National Park, central Vietnam
Credit: Asian Turtle Program
License: CC-BY 4.0

On the other hand, the study highlights that confiscated animals are of various origin and, therefore, must not be released arbitrarily where they have been seized. Instead, the researchers recommend that captive programmes establish regular genetic screenings to determine the origin of confiscated turtles, so that the risk of crossing different lineages is eliminated. Such genetic screenings are of crucial importance to solve the current issues with biodiversity conservation in the country and the region.

Like other developing countries, Vietnam does not have any specific guidelines on how to release confiscated animals back into the wild yet. This and other similar studies emphasise the role of the government in the implementation of stricter laws and regulation,”

said Dr. Minh D. Le, lead author of the study.

This research once more underscores the IUCN’s One Plan Approach, which aims to develop integrative strategies to combine in situ and ex situ measures with expert groups, for the purposes of species conservation,

added Dr. Thomas Ziegler of the Cologne Zoo.

The research was funded by the Critical Ecosystem Partnership Fund, the Partnership for Enhanced Engagement in Research (PEER), the United States Agency for International Development, the US Fish and Wildlife Service, Vietnam’s Ministry of Science and Technology and IDEAWILD.

Trapping four-eyed turtles in Pu Mat National Park, central Vietnam
Credit: Asian Turtle Program
License: CC-BY 4.0

Original source:

Le MD, McCormack TEM, Hoang HV, Duong HT, Nguyen TQ, Ziegler T, Nguyen HD, Ngo HT (2020) Threats from wildlife trade: The importance of genetic data in safeguarding the endangered Four-eyed Turtle (Sacalia quadriocellata). Nature Conservation 41: 91-111. https://doi.org/10.3897/natureconservation.41.54661

Contact: 

Dr Minh Duc Le, Vietnam National University
Email: le.duc.minh@hus.edu.vn

Newly discovered turtle species is facing extinction

For decades, it has been assumed that the Chinese Softshell Turtles from East Asia all belonged to one and the same species, Pelodiscus sinensis. Widely distributed all the way from the Russian Far East through the Korean Peninsula to China and Vietnam, the species was said to vary substantially in terms of its looks across localities. However, around the turn of the century, following a series of taxonomic debates, scientists revalidated or discovered a total of three species distinct from the ‘original’.

Recently, a Hungarian-Vietnamese-German team of researchers described a fifth species in the genus. Their discovery is published in the open-access journal ZooKeys.

The new species, which differs both genetically and morphologically from the other four, has well-pronounced dark blotches on the underside of its shell. The markings are also the reason why these turtles are going by the scientific name Pelodiscus variegatus, where “variegatus” translates to “spotted” in Latin.

“This morphological feature, among others, led to the discovery that these animals belong to a hitherto undescribed species,” explains Professor Dr. Uwe Fritz of the Senckenberg Natural History Collections in Dresden.

Unfortunately, the identification of multiple species within what used to be a single one has its potentially ill-fated consequences. While the Chinese Softshell Turtle was once considered widespread and not threatened, each newly discovered species “reduces” the individual population numbers.

“When we look at each species, the distribution range as well as the number of individuals is much smaller than when all were combined. Until now, the newly described Spotted Softshell Turtle was considered part of the Lesser Chinese Softshell Turtle Pelodiscus parviformis, which was discovered by Chinese researchers in 1997. Pelodiscus parviformis was already considered critically endangered. Now that its southern representatives have been assigned to a different species, the Spotted Softshell Turtle, the overall population size of each species is even smaller,” explains Balázs Farkas, the study’s Hungarian lead author.

Because of its restricted range and the levels of exploitation it is subjected to, the conservation status of the new species is proposed to be Critically Endangered, according to the criteria of the IUCN Red List of Threatened Species.

Habitat of the newly discovered softshell turtle, Pelodiscus variegatus. Photo by An Vinh Ong.

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Original source:

Farkas B, Ziegler T, Pham CT, Ong AV, Fritz U (2019) A new species of Pelodiscus from northeastern Indochina (Testudines, Trionychidae). ZooKeys 824: 71-86. https://doi.org/10.3897/zookeys.824.31376