Mega study shows how international pet trade favors invasive species

In the 1970s, Argentine parrot (Myiopsitta monachus) and that of Kramer (Psittacula krameri) were part of a lucrative and legal import market from their countries of origin to Spain to become companion animals. Released by their owners, as of 1975 some specimens in freedom began to be seen in Barcelona.

These birds already number in the thousands throughout the country due to their reproductive success and great resilience, and they have been included in the Spanish Catalog of Invasive Exotic Species. In fact, in the Madrid’s community a plan is planned to reduce their numbers and stop their invasion. But examples like that of the parrots exist all over the world.

The study shows that the pet trade not only creates opportunities for invasions, but favors invasive species

The burma python (Python bivittatus), introduced in Florida (USA), or the korean squirrel (Eutamias sibiricus) in central and eastern Europe, add to the long list of exotic animals that are transported from their native habitats to human homes, from which they escape or are released.

To better understand the causes of the spread of invasive species, Jérôme MW Gippet Y Cleo bertelsmeiera, from the Department of Ecology and Evolution of the University of Lausanne in Switzerland, have carried out a meta-analysis of the international pet trade, where they believed that invasive species could be overrepresented. In total, they collected data on 7,522 species of mammals, birds, reptiles, amphibians, and fish.

The results, published this week in the journal PNAS, reveal that 12.6% of commercialized pets are invasive species in some part of the world. In addition, the work shows that they are 7.4 times more frequent in this business than in the world calculation of vertebrate species.

“The world trade in exotic pets tends to particularly promote species with great potential to invade ecosystems outside their natural geographic zones,” he tells SINC. Gippet, first author of the study.

The scientists reached this conclusion by also analyzing the case of the emerging trade in ants as pets, too recent to be responsible even for any invasion. Despite this, invasive ant species are over-represented in this market, corroborating the fact that the pet trade not only creates opportunities for invasions, but favors invasive species.

Fight between an American alligator and a Burmese python in the Everglades National Park in Florida. / Lori Oberhofer, National Park Service

A danger to biodiversity and human health

The problem begins when, once released, these animals survive in their new areas. “Having an invasive species (or any species with invasion potential) as a pet is dangerous because, if this species escapes in nature, and manages to survive and reproduce, it could negatively impact native species, the ecosystem, agriculture or human health ”, says the scientist.

Species with invasive potential should not be traded as pets

Jérôme Gippet, ecologist

In the case of burma python for example, this has become a “real ecological problem because it is in competition with native predators”, explains the ecologist. korean squirrel it is also a vector for many parasites and diseases.

Although some of the most marketed and popular on the market are the royal python (Python regius) and the Florida terrapin (Trachemys scripta), there are other species that are “very dangerous because there is a high probability that they will invade other parts of the world if people buy them as pets and then let them escape (or release them),” adds Gippet.

Given the results of the work, the authors demand greater awareness of risk and regulations regarding the international trade in wild species as pets. “Prevention is better than cure,” the researcher tells SINC.

“A species can only become invasive if it is introduced outside of its natural range. Species with invasive potential should not be traded as pets ”, concludes Gippet, for whom it is essential to ensure that the species sold are not invasive before authorizing their trade.


Jérôme MW Gippet et al. “Invasiveness is linked to greater commercial success in the global pet trade” PNAS

Rights: Creative Commons.

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