Are they, aren’t they?: What it takes to declare a species extinct

It’s an error with a charming name, but very real consequences. “Erroneously declaring a species extinct could lead to its actual demise, simply because stakeholders may give up on trying to save it,” says P Jeganathan, a wildlife biologist with the NGO Nature Conservation Foundation (NCF).

So how does one know? By the guidelines of the International Union for Conservation of Nature (IUCN), a species may be declared extinct when there is “no reasonable doubt that the last individual has died”. In some cases, sadly, that reasonable doubt is becoming easier to erase, as crucial habitats erode.

Two new species of stingless bee from Tanzania and Madagascar, for instance, were recently identified, from among existing specimens collected over a century ago. Scientists were able to reasonably assume both extinct, because the conditions in which they lived simply do not exist in the small and rapidly changing habitats that once housed them.

In most of the world, the reasonable doubt can linger. And few countries have the means and manpower to conduct the kinds of exhaustive surveys required, and mandated by IUCN, to track even known endangered species. It is a daunting task even with larger mammals, and becomes incrementally harder with species that are smaller, nocturnal, or dwelling in hard-to-access habitats.

The solution, biologists suggest — Jeganathan is one among them — is to depend less heavily on enumeration. “It is more important to conserve entire habitats rather than focus on just species,” he points out. If a habitat is healthy, the species within it will be less at risk to begin with, and will be easier to spot as well.

A focus on long-term surveys is essential too, says Sanjay Sane, a professor who specialises in insect flight, at the National Centre for Biological Sciences (NCBS), Bengaluru. Such surveys require longer funding cycles. “The average cycle of government funding in India is three years, while a single long-term survey needs to be at least a decade long,” says Sane.

The use of student-level research could help. Agriculture students, for instance, conduct systemic surveys as part of their course work. Most of their findings are saved in silos, gathering dust.

At the University of Agricultural Sciences, Bengaluru, then professor of entomology VV Belavadi began doing things differently last year, cataloguing students’ findings to build an active archive. “During their course, each student collects about 50 insects and studies them,” he says. “We began cataloguing the species collected through these assignments, with descriptions of their nesting behaviours.” As these efforts continue at the institute, the hope is that, over the years, data on populations and patterns will accumulate, and trends will become apparent.

Given how little we know about the natural world, large stores of data from across sources is vital. As the oft-cited and reasonably accurate statistic has it, modern science has only identified about 14% of the species on Earth, and 9% of those in the oceans. (There are an estimated 8.7 million species globally.)

The IUCN Red List currently lists 150,388 at-risk species, from among those known to us and well-studied. It groups these across nine categories: Not Evaluated, Data Deficient, Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, and Extinct. Around the world, wildlife departments in individual countries track and list extinctions too.

We have meanwhile been declared to be in the midst of a sixth mass extinction — driven this time not by geological shifts and natural disasters but by human activity. Given this landscape, it is only by casting the widest net possible that we can assess where we stand; track and prevent extinctions; identify endangered habitats to protect (so as to eventually protect our own too). And celebrate the victories as species rebound.

In 2021, for instance, four species of commercially fished tuna were moved down the IUCN list of most-threatened, amid stricter laws and more effective enforcement.

In other good news, a species assumed extinct is currently in the process of being re-categorised, in a campaign that has animated communities of biologists and bird-lovers in the US. The species is the ivory-billed woodpecker, a majestic black-and-white bird with a bright red crown nicknamed the “Lord God” Bird, after the reaction its sighting evokes.

It was officially last sighted in 1944, and was almost taken off a list of protected animals and birds this year, because the US Fish and Wildlife Service intended to declare it extinct. Then a study led by researchers at the National Aviary in Pittsburgh was published in the journal Ecology and Evolution in May. It presented drone footage, audio recordings and images from trail cameras collected over a decade, to establish an “intermittent but repeated presence” of the bird. The Fish and Wildlife Service is now reconsidering its decision.

Which brings us full circle to the vital importance of data, collaboration and new approaches; and the complications of declaring a species extinct — even just one; even one already known to us.