|Credit Matilda Luk, Princeton University|
The wildlife trade involves thousands of vertebrate species and now rivals habitat loss as an extinction driver in some regions. However, its impacts are poorly known because field monitoring of wild populations is expensive, localized, and requires specialized expertise.
Approximately one third of the world’s birds sourced from most of Earth's ecosystems are traded. A staggering 1.5 billion live ornamental fish are exported every year. Thousands of reptile and mammal species are marketed legally and illegally. The illegal wildlife trade alone is worth US$10 billion per year, the total retail value of ornamental fishes adds up to US$2.2. billion and so on.
Wildlife trade affects thousands and thousands of species, yet for only a handful of species we have enough information to assess what effect continuous harvesting has on their populations. For the vast majority of species, we really don't know what impact wildlife trade is having. It is a silent killer. Species decimated by trade are not necessarily considered endangered. Nor does wildlife trade leave cleared forests or other obvious signs of destruction in its wake as activities such as mining or illegal logging often do.
Researchers from Princeton University thought of a different way to to gauge and perhaps halt the devastation of the wildlife trade on populations of prized animals. They found that species that are disappearing as a result of the pet trade can be identified by changes in their market prices and trade volumes. Increasing prices and decreasing availability could mean that wild populations are plummeting.
The researchers studied open-air pet markets on the Indonesian island of Sumatra and found that bird species that increased in price but decreased in availability exhibited plummeting populations in the wild. The researchers examined bird-market data from 1987 to 2013, and surveyed local ornithologists and expert birdwatchers to confirm that wild populations of the species most prized as pets declined as their price went up and market availability decreased.
They conclude that a prolonged rise in price coupled with a slide in availability could indicate that a species is being wiped out by its popularity in the pet trade. Through regular pet-market monitoring, conservationists and governments could use this information as an early indicator that a particular species is in trouble. At that point, more sophisticated measures could be taken to monitor and protect that species' wild population.
Market monitoring can be done far more quickly and cheaply than field-based monitoring of wild populations, especially in developing tropical countries where fieldwork requires special expertise and can be difficult to conduct. Those countries usually host a large number of species and have big markets for pets, yet have lax-to-nonexistent monitoring and conservation programs.
This study also highlights the pet trade as an emerging threat facing many birds and other wildlife, one that can act independently from other drivers of extinction such as habitat loss.