A two-stage translocation strategy for improving juvenile survival of Hawaiian monk seals

Abstract

We propose a two-stage translocation strategy to conservemetapopulations of endangered species. The concept takes advantage ofvariation in vital rates among subpopulations to increase individualfitness, improve species status, and maintain metapopulation structurefor long-term resiliency. We simulate two-stage translocation scenariosfor conserving the Hawaiian monk seal Monachus schauinslandi, acritically endangered species which exhibits highly variable juvenile,but consistently favorable adult, survival rates. Moving young sealsfrom areas of lower to higher juvenile survival and subsequentlyreturning them to their source site once they have reached anappropriate age improves population reproductive value. We present adecision framework for implementing two-stage translocation in a mannerthat minimizes risks while increasing the likelihood of desiredoutcomes. Two-stage translocation may be effective for metapopulationsof other rare species which exhibit variation in vital rates amongsubpopulations and a life-stage bottleneck due to factors that are notamenable to in situ mitigation.