The Endangered Species Act (ESA) has long been hampered by inadequate resources, leaving the US’s foremost law for protecting plants and animals filled with delays and failures in species recovery, researchers said on Wednesday.
The findings, published in the scientific journal Plos One on the eve of the law’s 50th anniversary, helped shed light on why, despite hundreds of species listed, only 54 in the country have fully recovered.
“It’s unfortunate that while we have this very noble law, we haven’t really given it the resources it needs to succeed,” said Erich K Eberhard, an author on the study.
The new report, which examined data from the Federal Register, found that since 1985, one of the main sources of funding for ESA has decreased by almost 50% when measured on a per species basis.
Although the law has been shown to be effective when it comes to keeping species from going extinct (it has saved over 99% of listed species from extinction, according to the US Fish and Wildlife Service), it has not been as successful when it comes to species recovery.
The authors explained that typically by the time a species has received protection, it has already reached “dangerously low population sizes”, which makes recovery extremely difficult.
Eberhard gave the example of the Sierra Nevada bighorn sheep, which was listed as endangered in 2000 when its population had been reduced to as few as 100 individuals. “Now we’re 20 years after the fact, it’s still an imperiled species listed by ESA,” he said.
Between 1992 and 1999 the average wait time for species petitioned for listing was 5.9 years, while between 2000 and 2009, it was 9.1 years, according to the study. In more recent years, it has been reduced to three years.
The ESA advises that there be only a two-year wait period, as longer delays can put a species, whose population is already very small, at greater risk.
But the report explained that the low population numbers probably had more to do with a long backlog of rare species, rather than a sudden decline in more common species while they waited to be listed.
The study built on a report published in 1993 that painted a similarly bleak picture of the law.
“In that paper we called for earlier protection of declining species,” explained David S Wilcove, professor of ecology at Princeton University, and an author on both the new and previous studies. “Then after the passage of almost 30 years, the question was, had anything changed? And the answer is no.”
The previous study found that from 1985 to 1991, the median population size when a species was listed by ESA was 1,075 for vertebrates and 999 for invertebrates. Viable population sizes for vertebrates are measured in the thousands, while invertebrates are even higher, explained Wilcove.
In the years since, the authors said the population sizes when listed by ESA have remained largely unchanged.
Today, the rate of species extinction has intensified due to such things as climate crisis, habitat loss and exploitation through hunting and overfishing. Approximately 1 million species are in danger of going extinct, some in a matter of decades, according to the 2019 Global Assessment Report on Biodiversity and Ecosystem Services.
At the time of this reporting, there were 1,270 plants and animals in the US listed as endangered and 402 listed as threatened.
The new report was published just two months before the Conference of the Parties to the Convention on Biological Diversity meeting, in which leaders from across the world are expected to adopt a plan for conserving biodiversity over the next few decades. The US is one of only a handful of nations that has not ratified the treaty, but has a history of participating.
Eberhard said as leaders start developing these ambitious goals, it would be good for them to consider the cautionary tale found within these findings.
“It’s great to have super-ambitious goals, [but] you need to back those up with real action,” he said. “In this case, real action is providing the Fish and Wildlife Service with the resources that it needs.”