Warnings of imminent extinction crisis for largest wild animal
species
Indian water buffalo (Bubalus arnee) in Kaziranga National Park, India, is an endangered bovid with a global population estimated at fewer than 4,000 individuals in the wild.
Credit: Varun R. Goswami, WCS India Program
A team of conservation biologists is calling for a worldwide strategy to prevent the unthinkable: the extinction of the world's largest mammal species.
In a public declaration published in today's edition of the journal BioScience, a group of more than 40 conservation scientists and other experts are calling for a coordinated global plan to prevent the world's "megafauna" from sliding into oblivion.
Among the threats cited by the group as drivers of this mass extinction are illegal hunting, deforestation and habitat loss, the expansion of agriculture and livestock into wildlife areas, and the growth of human populations.
"The more I look at the trends facing the world's largest terrestrial mammals, the more concerned I am we could lose these animals just as science is discovering how important they are to ecosystems and to the services they provide for people," said Dr. William Ripple, professor of ecology at Oregon State University and lead author of the study.
Ripple worked with other authors on the study to examine population trends of many species, including many of the most well-known, charismatic species such as elephants, rhinos, gorillas, and big cats that are now threatened with extinction.
Approximately 59 percent of the world's biggest mammalian carnivore species -- including the tiger -- and 60 percent of the largest herbivores are now listed on the International Union for Conservation of Nature's Red List of Threatened Species as threatened with extinction.
"Perhaps the biggest threat for many species is direct hunting driven by a demand for meat, pets, and body parts for traditional medicines and ornaments," Dr. Elizabeth Bennett, WCS's Vice President of Species Conservation and a co-author on the study. "Only a massive commitment from the international community will stop this rampant destruction of so many animal populations."
All of these large species play critical roles in their ecosystems. Species at risk include elephants, that provide a suite of vital ecosystem services as ecological engineers, dispersing seeds and nutrients across vast areas. "The loss of elephants in the forests of Central Africa is increasingly damaging the function of the region's most important ecosystems," said WCS Conservation Scientist Dr. Fiona Maisels, one of the study's co-authors. "We're only beginning to understand how vital these keystone species are to the health of rainforests and other species that inhabit them."
Human-wildlife conflict is a serious concurrent threat for many species. "With simultaneous loss of wildlife habitat and expansion of human populations and agriculture, negative interactions between people and wildlife are bound to rise," said WCS India Scientist Dr. Varun R. Goswami, also a co-author on the study. "For wide-ranging megafauna like elephants and tigers, we need landscape-scale conservation strategies, taking into account the increasing interface between wildlife and people."
Some megafauna face the threat of obscurity. The loss of elephants worldwide to poachers in pursuit of ivory is well-known and is the focus of extensive efforts to shut down this trade, but the study authors point out that many species are at risk from many similar threats but are so poorly known that effective conservation efforts to save them are difficult.
The paper includes a 13-part declaration that highlights the need to acknowledge the threatened status of many large mammals and the vital ecological roles they play. The declaration also cites the importance of integrating the efforts of scientists and funding agencies in developing countries where many species occur; the need for a new global framework to conserve megafauna; and the moral obligation of saving the world's biggest mammal species.
Should the gray wolf keep its endangered species protection?
New genomic research provides the scientific answer
Gray wolves are currently protected under the US Endangered Species Act (and are not always gray).
Credit: Dan Stahler
Research by UCLA biologists published today in the journalScience Advances presents strong evidence that the scientific reason advanced by the U.S. Fish and Wildlife Service to remove the gray wolf from protection under the Endangered Species Act is incorrect.
A key justification for protection of the gray wolf under the act was that its geographic range included the Great Lakes region and 29 Eastern states, as well as much of North America. The Fish and Wildlife Service published a document in 2014 which asserted that a newly recognized species called the eastern wolf occupied the Great Lakes region and eastern states, not the gray wolf. Therefore, the original listing under the act was invalid, and the service recommended that the species (except for the Mexican gray wolf, which is the most endangered gray wolf in North America) should be removed from protection under the act.
A decision by the U.S. Fish and Wildlife Service to remove the gray wolf from protection under the Endangered Species Act may be made as early as this fall.
In the new study, biologists analyzed the complete genomes of North American wolves -- including the gray wolf, eastern wolf and red wolf -- and coyotes. The researchers found that both the red wolf and eastern wolf are not distinct species, but instead are mixes of gray wolf and coyote.
"The recently defined eastern wolf is just a gray wolf and coyote mix, with about 75 percent of its genome assigned to the gray wolf," said senior author Robert Wayne, a UCLA professor of ecology and evolutionary biology. "We found no evidence for an eastern wolf that has a separate evolutionary legacy. The gray wolf should keep its endangered species status and be preserved because the reason for removing it is incorrect. The gray wolf did live in the Great Lakes area and in the 29 eastern states."
Once common throughout North America and among the world's most widespread mammals, the gray wolf is now extinct in much of the United States, Mexico and Western Europe, and lives mostly in wilderness and remote areas. Gray wolves still lives in the Great lakes area, but not in the eastern states.
Apparently, the two species first mixed hundreds of years ago in the American South, resulting in a population that has become more coyote-like as gray wolves were slaughtered, Wayne said. The same process occurred more recently in the Great Lakes area, as wolves became rare and coyotes entered the region in the 1920s.
The researchers analyzed the genomes of 12 pure gray wolves (from areas where there are no coyotes), three coyotes (from areas where there are no gray wolves), six eastern wolves (which the researchers call Great Lakes wolves) and three red wolves.
There has been a substantial controversy over whether red wolves and eastern wolves are genetically distinct species. In their study, the researchers did not find a unique ancestry in either that could not be explained by inter-breeding between gray wolves and coyotes.
"If you did this same experiment with humans -- human genomes from Eurasia -- you would find that one to four percent of the human genome has what looks like strange genomic elements from another species: Neanderthals," Wayne said. "In red wolves and eastern wolves, we thought it might be at least 10 to 20 percent of the genome that could not be explained by ancestry from gray wolves and coyotes. However, we found just three to four percent, on average -- similar to that found in individuals from the same species when compared to our small reference set."
Pure eastern wolves were thought to reside in Ontario's Algonquin Provincial Park. The researchers studied two samples from Algonquin Provincial Park and found they were about 50 percent gray wolf, 50 percent coyote.
Biologists mistakenly classified the offspring of gray wolves and coyotes as red wolves or eastern wolves, but the new genomic data suggest they are hybrids. "These gray wolf-coyote hybrids look distinct and were mistaken as a distinct species," Wayne said.
Eventually, after the extinction of gray wolves in the American south, the red wolves could mate only with one another and coyotes, and became increasingly coyote-like.
Red wolves turn out to be about 25 percent gray wolf and 75 percent coyote, while the eastern wolf's ancestry is approximately 75 percent gray wolf and 25 percent coyote, Wayne said. (Wayne's research team published findings in the journal Nature in 1991 suggesting red wolves were a mixture of gray wolves and coyotes.)
Although the red wolf, listed as an endangered species in 1973, is not a distinct species, Wayne believes it is worth conserving; it is the only repository of the gray wolf genes that existed in the American South, he said.
The researchers analyzed SNPs (single nucleotide polymorphisms) -- tiny variations in a genetic sequence, and used sophisticated statistical approaches. In the more than two dozen genomes, they found 5.4 million differences in SNPs, a very large number.
Wayne said the Endangered Species Act has been extremely effective. He adds, however, that when it was formulated in the 1970s, biologists thought species tended not to inter-breed with other species, and that if there were hybrids, they were not as fit. The scientific view has changed substantially since then. Inter-breeding in the wild is common and may even be beneficial, he said. The researchers believe the Endangered Species Act should be applied with more flexibility to allow protection of hybrids in some cases (it currently does not), and scientists have made several suggestions about how this might be done without a change in the law, Wayne said.
