The conservation paradox: Invasive species are often threatened in their native habitats

Introduced species introduced by humans are one of the main causes of global species decline, and were partly responsible for 60% of species that have gone extinct around the world in recent decades. Introduced mammals in Central Europe include species such as the brown rat, mouflon, and mink.

Now, a study led by biologists from the University of Vienna and La Sapienza University in Rome shows that some of these species introduced by humans are themselves at risk of extinction in their native regions. Shown. The study was published in the latest issue of the journal Conservation Letters.

Globalization of the earth introduces many plant and animal species to new regions of the world. Invasive species can displace native species through competition or carry new diseases. However, at the same time, some of these invasive species are at risk of extinction within their native ranges.

This creates a conservation paradox. Because the question now is whether to protect or fight alien populations of species that are threatened with extinction in their native range. However, until now it was unknown how many exotic mammals this paradox actually applies to. In a new study, scientists have quantified this paradox to move one step closer to an answer.

A total of 230 species of exotic mammals have been introduced by humans to new areas and are permanently resident there. “We were interested in how many of these species are at risk of extinction in their homeland,” said Lisa, from the University of La Sapienza and the University of Vienna, lead author of the study.・Mr. Tedeschi explains.

Scientists were able to show that 36 of the exotic mammal species are endangered in their native homelands and therefore fall under this conservation paradox. “We were very surprised by this high number, as we had assumed that non-native species were common in their native regions,” Tedeschi continued.

One of the important endangered native mammals is the Crested Monkey, whose population has declined by 85% in its native habitat on Sulawesi since 1978, but has continued to grow in other Indonesian islands. It has also spread and maintains a stable population. Wild rabbits are endangered in Europe, but other parts of the world, such as Australia, have introduced very large populations, much larger than in Europe.

Most native endangered species originate from tropical Asia. Their decline is often the result of large-scale rainforest destruction and overfishing. Therefore, human-introduced populations may help prevent the extinction of these species.

Globalization: conservation faces difficult challenges

Assessing global extinction risk does not currently take into account the occurrence of species that are no longer in their native range. However, in this study, the researchers were able to show that the extinction status of some species could be improved if invasive species were also taken into account.

“For 22% of the species analyzed, the risk of global extinction would be reduced if non-native species were also included in the assessment,” said one of the study’s lead authors, Professor of Biodiversity at the University of Vienna Sex researcher Franz Essl explains. Scientists say the results highlight the considerable importance of exotic populations to the survival of endangered species, especially when there are high levels of threat to native habitats.

However, including non-native populations of these species in threat assessments also carries risks. For example, less attention is paid to protecting populations of endangered species in native areas. Furthermore, exotic populations can have negative effects on other species.

“The main focus must continue to be on the conservation of native species; There may be more species in the area.

“This poses a difficult challenge for nature conservation: weighing opportunities and risks,” Franz Essl concluded. “This is also a sign of the globalization of species distribution.”