Professor Princeton University Princeton, New Jersey, United States
Background/Question/Methods
Accelerating rates of species extinction is a matter of global concern. In the U.S., the strongest law to prevent species extinctions is the Endangered Species Act (ESA). However, a longstanding concern has been the relatively few ESA-listed species that have successfully recovered to the point of no longer needing protection.
This low rate of recovery may be due to a pattern of not protecting species under the ESA until their populations have reached dangerously low levels, which increases time to recovery and the likelihood of stochastic extinction. Evidence of this pattern was initially provided in a 1993 paper by Wilcove et al. We repeated their methodology for the 1992–2020 time period to determine whether the US Fish & Wildlife Service (FWS) has become more proactive as we approach the 50th anniversary of the ESA and roughly 30 years since attention was first drawn to this problem.
We also examine trends in the length of time (t) between when a species is first identified as potentially deserving of protection and when it actually receives protection under the ESA (“wait-times”), as well as trends in funding for the listing and recovery of imperiled species.
Results/Conclusions
Total number of individuals and number of populations at time of listing did not differ significantly between the 1985-1991 and 1992-2020 periods (Wilcox Test: p = 0.0825, p</em> = 0.9111; p = 0.4068, p = 0.0433; and p = 0.6642, p = 0.0596, for plant, vertebrate, and invertebrate total number of individuals and number of populations, respectively). Consistently, few species have received protection in the one-year period prescribed in the ESA.
Our data suggest that inadequate funding is the root of these problems. An inflation-adjusted analysis of appropriations for the listing of new species shows that funds climbed modestly from 1996–2010 before beginning a decade-long decline that was halted only in 2020. Appropriations to recover listed species, measured on a per species basis, have dropped by nearly 50% since 1985. In short, FWS is being asked to do more with less resources. Inadequate funding for recovery actions and delays in listing, coupled with small populations, are likely the key factors that explain the low rate of recovery of ESA-listed species.
The U.S.’s failure to solve the funding gaps that undermine the ESA is a stark reminder of the difference between the promise of change and its functional implementation.
