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Reintroductions & Translocations Continue to be an important tool in wildlife management Wildlife Reintroductions • Does habitat remain? – – – – How much? Connected? Management? Competition / Predation / Diseases Wildlife Reintroductions • Viable Population? – PVA • VORTEX • RAMAS Wildlife Reintroductions • Viable Population? – PVA • VORTEX • RAMAS • Incorporate GIS Wildlife Reintroductions • Genetic Considerations – Why should you care? – Genetic swamping? Genetic Considerations: Why Should You Care? • Genetic variation is the underlying basis for adaptation to future environmental change • Loss of genetic variation is often a direct consequence of species reintroduction • Understanding how genetic loss occurs can help to prevent management actions that decrease the genetic diversity of reintroduced wildlife species Wildlife Reintroductions • Genetic Considerations – Inbreeding – Did we release highly related individuals? Wildlife Reintroductions • Genetic Considerations – Founder Effect Founder Effect • The reduction in overall genetic diversity experienced as a consequence of population establishment from a limited sample of individuals – Most reintroductions and natural colonization events exhibit Founder Effects – The magnitude of the effect depends upon the number of animals translocated or colonizing an area Wildlife Reintroductions • Genetic Considerations – Genetic Bottleneck Bottleneck • An event in which a population drops significantly in size and then recovers • Events such as habitat loss, over harvest, or reintroduction can create bottlenecks and the magnitude of the effect on genetic diversity depends upon: – Number of individuals at lowest point – Length of time population remains depressed Genetic Drift • Random fluctuations in gene frequencies due to temporal variance in survival and reproduction – Small populations drift more rapidly than large ones – Higher reproductive and survival rates can slow the rate of genetic drift – Genetic drift can result in loss of genetic diversity as well as increases in the frequency of rare alleles Inbreeding • Mating of closely related individuals • Anytime genes that are alike by descent (i.e., from a shared ancestor) come together within individuals – Enhanced by slow population growth rates – Affected by mating system – Influenced by the relatedness of the initial population founders (e.g. reintroductions) Hypothetical Source Population Different Colors Represent Copies of Different Genes Trap and Transplant Reintroduced Population Loss of From Alleles • Small Samples Source Due to Original • Incomplete Sampling of Genes Sampling Event • Sampling of Related Groups Founder Effects Loss of Alleles Due • Differential Survival of Founders Post-Release • Differential Survival of Offspring to Stochastic Processes • Differential Reproductive Contributions Loss of Alleles Due to • Inefficient Transfer of Genes Stochastic And • UnequalDeterministic Reproductive Contributions • Differential Survival Processes • Mating of Closely Related Individuals Over Generations 10 10 Generation Bottleneck Genetic Drift Inbreeding 20 Generation Bottleneck 20 Loss of Allelic Diversity Apparent Genetic Drift Inbreeding 30 30 Generation Bottleneck Loss of Allelic Loss of Allelic Diversity Dramatic Diversity Dramatic Common Allele Rare Allele Predominant Predominant Genetic Drift Inbreeding Wildlife Reintroductions • Genetic Considerations – Marten reintroductions
