Back from the Brink: Extinction doesn't have to be a Death Sentence
How fast must you run to stay in the same place? That’s what Alice had to ask herself when racing with the Red Queen in Lewis Carroll’s Through the Looking Glass. Often conservation biologists and scientists have to ask themselves the same question. Annie discusses more…
Evidence suggests that we’re already in the sixth mass extinction event, with more than 35,000 species threatened with extinction. Attempting to save a species from the brink of extinction can often feel like an uphill battle and to get somewhere then you must run at least twice as fast. But hope is not lost as we have come to find that extinction isn’t always a death sentence.
Since 1993, conservation efforts have saved around 48 species of birds and mammals from the brink of extinction. One such success story is that of the California Condor (Gymnogyps californianus). The Condor was threatened to near extinction by habitat destruction and lead poisoning from eating carcasses of animals containing lead bullet fragments. In 1987 the last of the 27 wild birds were captured, rendering the species extinct in the wild. Captive breeding programs were introduced in an attempt to save the species. Over the years California Condor have been reintroduced into the wild and as of March 2020, there were 93 mature individuals in the wild. Scientists are hopeful that they will continue to breed and that their numbers will increase. Lead poisoning once led to almost 50% of the deaths in the California Condor population and is still the species greatest threat to survival.
California Condor by Alicia Hayden
Another success story is that of the Guam Rail (Hypotaenidia owstoni), a fast-running flightless bird and the second bird in history—after the California Condor—to recover after being declared extinct in the wild. The Guam Rail was once widespread on the island of Guam but its numbers started to decline after the accidental introduction of Brown Tree Snake (Boiga irregularis) to the island at the end of World War II. The last wild Guam Rail was killed by this invasive predator in 1987. Luckily 22 birds were brought into captivity to save the species. After a difficult 35-year-long breeding program, the Guam Rail has been re-established on the neighbouring Coco Island that is free from the invasive Brown Tree Snake. There has been some evidence of breeding in the wild and the IUCN suggests that the bird can be found throughout the island, but the population is likely to be small. The Brown Tree Snake has done significant damage to Guam’s fauna and projects to wrangle the snake population are still underway.
Guam Rail by Alicia Hayden
Przewalski's Horse is another species that was formerly extinct in the wild but has been successfully translocated. All Przewalski's Horses that are alive today are the descendants of 13 wild-caught horses that were bred with domestic horses. The new population is still very genetically similar to the wild horses and are slowly being reintroduced into Mongolia and China. There are close to 180 mature horses in the wild and according to IUCN, the population is slowly growing.
Przewalski’s Horse by Nathalie Dickinson.
Captive breeding programs with the intent to reintroduce endangered species into the wild have had varying levels of success worldwide. According to IUCN, while close to 80 species of plants and animals are extinct in the wild, they are holding on by a thread in botanical and zoological collections. Although reintroduction is usually the end goal of a captive breeding program, it is notoriously difficult to reintroduce a captive species into the wild.
The reintroduction programs to ‘rewild’ the Giant Panda are an example of this. The success rates are notoriously low and captured individuals have a hard time socializing with their wild kin. Yet hope is not lost, a recent study details the successful rewilding of three Giant Pandas and with more information on the best ways to reintroduce future captive animals back into the wild.
Giant Panda by Aimee Lee.
Captive breeding and reintroduction programs are just one facet of conservation. Protecting areas, implementing conservation legislation, and better public awareness are all key to save endangered species. For example, over the past 30 years, projects to conserve China’s bamboo forests have had a positive impact by increasing forest cover and improved connectivity between Giant Panda habitats. The 1988 Wildlife Protection Act conferred protected status to Giant Pandas and was instrumental in curbing poaching. As well as this, the bear is well-loved by the public and considered the face of animal conservation. This has helped raise funds and protect the declining bamboo forests from the effects of climate change.
New scientific advancements in genetic research have given conservation a new weapon to combat extinction. Just last month scientists cloned Willa, a black-footed ferret (Mustela nigripes) that lived more than 30-years ago, to add to the genetic diversity of the declining population of a critically endangered species. The genes of all of the black-footed ferrets alive today can be traced back to seven individuals. This means that the resultant lack of genetic diversity could cause major problems when trying to re-establish the species. Willa’s genome contained three times more unique variations than the entire living species possess. So if her clone, affectionately named Elizabeth Ann, were to mate successfully and reproduce then she would introduce her unique genetic diversity to the species. This is important because a small gene pool usually means a higher chance of contracting diseases or being born with a genetic disability and lower fertility rates, limiting the species ability to adapt to new habitats. But Elizabeth Ann’s genes could give the black-footed ferrets a better chance at survival.
It’s not just the species that we know about that are threatened with extinction, biodiversity hotspots in remote and unstudied parts of the country are currently under threat and we do not have structures in place to protect them from extinction. A large number of species are still being discovered every year. Hundreds of new species were discovered in 2020, an iridescent Vietnamese snake (Achalinus zugorum), an Iranian ‘Joker’ spider (Loureedia phoenixi), and a new species of monkey (Trachypithecus popa) from Myanmar that is unfortunately already on the critically endangered list. Scientists from the Natural History Museum alone were credited with identifying a whopping 503 new species. But unfortunately, some species are going extinct before they can even be discovered. This is what happened to the San Cristóbal vermilion flycatcher (Pyrocephalus dubius) in 2016. It was a strikingly beautiful bird with a unique song that puzzled scientists because, while it looked similar to another species of flycatcher it had a different call. Genetic studies proved that it was a distinct species but the celebrations were short-lived because promptly after being discovered it went extinct, never to be heard again.
Climate change and the exploitation of forests are two of the main culprits behind extinction. But hope is not lost, the Convention on Biological Diversity (CBD) adopted an ambitious plan to conserve biodiversity with a 2020 deadline. One of the targets was to prevent the extinction of species with threatened status and to improve and sustain the conservation status of species that are in the most decline. If the rate of extinction that was documented between 1993 to 2009 was allowed to continue, then in the past decade the number of extinction events would have been 2 to 4 times higher than they are today. And while not all the targets of the CBD were met, human efforts have saved up to 48 species of birds and mammals from extinction. Leaving us optimistic that the race is not lost and that extinction is no longer an inevitable death sentence.
Thank you to Alicia Hayden, Aimee Lee and Nathalie Dickinson for their wonderful illustrations. You can find more of their work at @aliciahaydenwildlife, @alllustration and @nathalied_art.
Annie Megan Santamaria
Annie is an MSc. graduate from the University of Exeter with interests in disease evolution. She is passionate about her research and aspires to make a positive impact on human and animal welfare. Annie was a part of the editorial team at Gubbi Labs where she managed an online science news journal and created graphics, podcasts and wrote pieces on scientific developments. Her goal is to bridge the gap between the researcher and the public by making science more accessible and easy to understand.
You can find her on Instagram @megansmaria.