动物园的物种保护工作太过随意

The world's zoos work hard and spend enormous resources on the conservation of endangered species, but the resources are not always optimally spent. One big problem is international legislation and the need of more zoos to work in regional or global networks. Zoo resources can be spent much more effectively, say scientists from University of Southern Denmark after analyzing animal collections across the world's zoos. Many zoos work hard to protect and breed endangered animal species in captivity, and they spend a lot of money doing so. But the effort is too random and the work is crippled by international legislation, making it impossible to optimize the conservation efforts. There is a need for an international joint strategic effort if we want good results from all the money spend, conclude the researchers, ecologists Dalia A. Conde, Owen Jones and Fernando Colchero from the University of Southern Denmark in the scientific journal PLOS One.

"The prevalence of threatened species in zoo's do not always reflect the number of threatened species in the wild," says Dalia Conde.

For example, although zoo collections are heavily focused on birds, there are only few threatened birds in zoos. Contrary to this zoos have a heavy focus on threatened turtles (Testudines) and carnivorous marsupial (Dasyuromorphia).

Regarding to the high number of threatened marsupials, Dalia Conde explains that Australian zoos are trying to use these species not only for captive breeding programs but also to educate people about the threats, that a local species faces.

"As for the high number of turtles, one of the reasons is that the zoos have to take over many confiscated（充公，没收） animals after smugglers have tried to trade them illegally," she says.

The prevalence of endangered species in zoos therefore not always reflects the prevalence in nature. Two groups -- the turtles and carnivorous（食肉的） marsupial -- are overrepresented, while most groups of threatened species are the result of opportunistic collections rather than a major focus. Besides birds, threatened amphibians, insect-eating mammals (Eulipotyphyla) and rodents (Rodentia) are underrepresented in the world's zoos. In fact not a single one of the 84 endangered species of insectivorous（食虫的） mammals are found in zoos. Among mammals about half (92 of 201) of the endangered species are found in zoos. Overall, 57 out of the 59 animal orders that are found in zoos have a lower proportion of threatened species in zoos than in the wild.

This discrepancy is not the only challenge for conservation work in the zoos, the authors point out:

"Many zoos hold only a small population of an endangered species and they are struggling to make the populations grow. The zoos need to be able to share experiences and individuals with other populations in order to get a healthy growing population. But this is difficult, if not impossible, when there are thousands of miles between populations of the same species and it is highly challenging to get permits to exchange animals," the researchers explain.