Species recovery and recolonization of past habitats: lessons for science and conservation from sea otters in estuaries

PeerJ

article

Brent B. Hughes¹  Kerstin Wasson³  M. Tim Tinker⁴  Susan L. Williams⁶  Lilian P. Carswell⁷  Katharyn E. Boyer⁸  Michael W. Beck⁹  Ron Eby³  Robert Scoles³  Michelle Staedler^1,10  Sarah Espinosa⁴  Margot Hessing-Lewis^1,11  Erin U. Foster^1,11  Kathryn M. Beheshti⁴  Tracy M. Grimes^1,13  Benjamin H. Becker^1,14  Lisa Needles^1,15  Joseph A. Tomoleoni⁵  Jane Rudebusch^1,16  Ellen Hines^1,16  Brian R. Silliman² 

[1] Department of Biology, Sonoma State University;Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University;Elkhorn Slough National Estuarine Research Reserve;Department of Ecology and Evolutionary Biology, University of California;U. S. Geological Survey, Western Ecological Research Center;Department of Evolution and Ecology, Bodega Marine Laboratory, University of California;Ventura Fish and Wildlife Office;Estuary & Ocean Science Center, Department of Biology, San Francisco State University;Institute of Marine Sciences, University of California;Monterey Bay Aquarium;Hakai Institute;Applied Conservation Science Lab, University of Victoria;Department of Biology, San Diego State University;Point Reyes National Seashore, United States National Park Service, Point Reyes Station;Center for Coastal Marine Sciences, Department of Biological Sciences, California Polytechnic State University—San Luis Obispo;Estuary & Ocean Science Center, Department of Geography and Environment, San Francisco State University

关键词: Marine Mammal Protection Act;    Estuary;    Food web;    Fisheries;    Restoration;    Endangered Species Act;    Top predator;    Recovery;   

DOI  :  10.7717/peerj.8100

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Recovering species are often limited to much smaller areas than they historically occupied. Conservation planning for the recovering species is often based on this limited range, which may simply be an artifact of where the surviving population persisted. Southern sea otters (Enhydra lutris nereis) were hunted nearly to extinction but recovered from a small remnant population on a remote stretch of the California outer coast, where most of their recovery has occurred. However, studies of recently-recolonized estuaries have revealed that estuaries can provide southern sea otters with high quality habitats featuring shallow waters, high production and ample food, limited predators, and protected haul-out opportunities. Moreover, sea otters can have strong effects on estuarine ecosystems, fostering seagrass resilience through their consumption of invertebrate prey. Using a combination of literature reviews, population modeling, and prey surveys we explored the former estuarine habitats outside the current southern sea otter range to determine if these estuarine habitats can support healthy sea otter populations. We found the majority of studies and conservation efforts have focused on populations in exposed, rocky coastal habitats. Yet historical evidence indicates that sea otters were also formerly ubiquitous in estuaries. Our habitat-specific population growth model for California’s largest estuary—San Francisco Bay—determined that it alone can support about 6,600 sea otters, more than double the 2018 California population. Prey surveys in estuaries currently with (Elkhorn Slough and Morro Bay) and without (San Francisco Bay and Drakes Estero) sea otters indicated that the availability of prey, especially crabs, is sufficient to support healthy sea otter populations. Combining historical evidence with our results, we show that conservation practitioners could consider former estuarine habitats as targets for sea otter and ecosystem restoration. This study reveals the importance of understanding how recovering species interact with all the ecosystems they historically occupied, both for improved conservation of the recovering species and for successful restoration of ecosystem functions and processes.

【 授权许可】

CC BY