Factors Associated with Preemptive Conservation of Imperiled Species under the US Endangered Species Act

The US Endangered Species Act (ESA) serves a key role in protecting and recovering imperiled species. However, species’ populations are often already highly vulnerable to extinction by the time they are listed, making their recovery challenging. In recent decades, increasing emphasis has been placed on proactive efforts to conserve species that are being considered for listing under the ESA before they are listed (i.e., preemptive conservation); the aim is to increase conservation benefits while avoiding the regulatory burdens and costs associated with ESA listings. Such conservation and listing outcomes depend on the cumulative effect of voluntary actions by public and private land managers across the species’ range. Engagement in conservation actions is influenced by the costs, benefits, and barriers that land managers face, which can be affected by their social, economic, environmental, and institutional context. In this study, we explore the importance of contextual factors that we hypothesized could influence voluntary decisions to promote or inhibit preemptive conservation of species that are under consideration for ESA listing. We empirically estimate each factor's association with preemptive conservation outcomes, using data for a set of species that entered the ESA listing process and were either officially listed (n = 314) or preemptively conserved (n = 73) between 1996 and 2018. We find that factors associated with precluded listing due to preemptive conservation include higher baseline conservation status, a lower proportion of private land across the species’ range, smaller total range size, facing specific types of threats, and the species’ range occurring in a greater number of states. These results can help inform conservation strategies to further promote preemptive conservation outcomes, including targeting resources toward imperiled species earlier in the listing process, addressing specific threats, and expanding incentives and coordination mechanisms to further encourage preemptive conservation actions by private landowners.