The Ark Isn’t Always the Best Option for Saving Endangered Wildlife
Dozens of wildlife species go extinct every 24 hours, by some estimates—a wave of change so fast that it’s been termed the “sixth great extinction” because it’s on par with the mass die-offs caused by asteroid strikes and other natural forces millions of years ago.
So it seems like a no-brainer that when a species is threatened with vanishing forever, people should try to breed the animals in captivity.
But biologists should think twice before removing animals from the wild to breed them, said Paul Dolman, a conservation ecologist at the University of East Anglia who specializes in preserving species in human-modified landscapes.
“Captive breeding can clearly be really valuable and really important for some species in some situations,” said Dolman. But “it isn’t always the right option for saving a species that’s at risk of extinction.”
Dolman is the lead author on a new study that, for the first time, gives conservation scientists a tool for comparing the potential of captive versus wild breeding to save a species from extinction. Dolman’s research was published Thursday in the Journal of Applied Ecology.
“Typically, when a species is going extinct, captive breeding is established at a cost of millions of dollars with no sureness of success, ” he said. “We’re saying that before you put all your eggs in one basket, it’s important to objectively evaluate how likely it is to be a success.”
Criticism of captive breeding has grown in recent years because it can reduce a species’ genetic diversity, which harms survival rates. The emphasis on breeding in captivity can also diminish both money and momentum for saving equally vital wild habitat.
“Having worked in zoos, there is a lot of effort; zoos are trying to do conservation,” said Peyton West, director of the Frankfurt Zoological Society U.S., a group focused on conserving rhinos and other species in the wild. But “because it’s so difficult to release captive-bred animals back into the wild, there’s a lot that goes on in zoos, under the heading of captive breeding, that never results in release.”
The great Indian bustard, the large bird at the center of Dolman’s study, has gone extinct in 90 percent of its historical range, according to the EDGE database. Habitat loss and degradation “driven by the need for agriculture, infrastructure, mining, as well as poor habitat management” are the main factors now pushing it toward extinction.
Dolman and his colleagues gathered data on clutch size, chick survival rate, time to sexual maturity, and other details of the bustards’ life history in the wild and in captivity. Then they mathematically analyzed, or modeled, whether captive breeding or wild breeding would be more likely to save the species.
They found that with bustards, the factors combined to make a focus on captive breeding a path to likely extinction.
Keeping the bird in the wild while also saving its habitat had a better chance of saving it from extinction, with the population increasing within five to 10 years and two to three times as many wild adults surviving in the wild within 20 to 30 years.
The model can be used with other large bird species, Dolman said.
West lauded the move to a more analytical approach to conservation decisions. “With some animals there just isn’t going to be an option to save them by breeding in the wild,” she said, “while with others, their behaviors are too complicated” to make captive breeding a hopeful option.
“I think the California condor is a good example of where without a captive breeding program, there was no chance for those birds,” she said.
But perhaps with the great Indian bustard, “you can’t teach them to do it in captivity in a way that will allow them to survive in the wild.”
So, Why Should You Care? The health of human communities depends on the plants, animals, land, air, and water that make up the planet’s biosphere, its layer of life. Without them, crops are more vulnerable to collapsing, and forests and gardens are more exposed to diseases and die-offs. Potential new medicines and materials will be lost. And living on Earth will be a lot less fun and exciting.