COS 62-4 - How can lost wildlife migrations be restored? Key drivers of success across taxa and ecosystems

Background/Question/Methods

Global declines in wildlife migrations have prompted new initiatives to conserve remaining migratory behaviors. However, amid ongoing losses of migratory behaviors, a key related question has been mostly overlooked: Once a migration has been lost, how can it be restored? Important attempts have been made to recover extirpated migrations, and our understanding of restoration remains narrowly confined to these particular species and landscapes. Here, we examine diverse restoration efforts through the unifying lens of behavioral ecology to draw broader inferences regarding the feasibility and effectiveness of restoring lost migrations. First, we discuss recent developments in migration ecology that broadly inform prospects for restoration. Then, we bring together case studies of restoration attempts across four major taxonomic groups (fish, birds, mammals, and herpetofauna) to synthesize common themes influencing restoration success among terrestrial and freshwater vertebrates. From this evaluation, we develop a conceptual framework to help inform restoration efforts across taxa, and we identify opportunities for conservation work and research to fill remaining knowledge gaps.

Results/Conclusions

We identify three broad strategies comprising seven specific techniques capable of effectively restoring lost migrations. First, lost migratory populations can be reestablished (via techniques of either translocating wild animals or releasing captive-bred animals). Second, lost habitats can be recovered (by techniques aimed at restoring seasonal ranges, reestablishing habitat connectivity, or restoring stopover sites). Third, lost behavioral patterns can be revived (using techniques involving teaching animals or facilitating social learning). We find that success of these efforts relies on common aspects of behavioral ecology that transcend taxonomic and geographic boundaries, so we identify and explore the key biological mechanisms underpinning the success of each. Additionally, we explore key roles of exploration, learning, and adaptation in wildlife migration; explicitly consider instances in which restoration may be ineffective or inappropriate; and define actions that can be taken by policymakers, management agencies, nongovernmental organizations, and community groups to develop beneficial restoration efforts. Our work reveals a previously underappreciated potential for restoring lost migrations in terrestrial and freshwater vertebrates, and it provides guidance on whether and how conservation practitioners, researchers, and policymakers can work to restore the valuable migrations we have lost.