Additional Population Viability Analysis of the Scandinavian Wolf Population

• Population modeling was carried out to estimate the effects of immigration into the Scandinavian wolf population using realistic genetic assumptions and to examine the trajectory of genetic diversity under a variety of scenarios. Initial modeling sought to establish the most up to date demographic parameters and genetic data, particularly focusing on ways to adequately model inbreeding within the population, and sought to examine the effects of varying these parameters on the outcomes of models by following the population from foundation in 1983 until 2008. The first set of forward modeling parameters were examined for a range of population sizes and immigration rates without using allele frequencies for the population and with immigrants being modeled using supplementation (that assumes immigrants are genetically unique compared to the population they are immigrating into). The results concluded that an acceptable loss of gene diversity and an increase in inbreeding coefficient of within 10% could be achievable in larger population sizes (370 and greater) with as little as one effective migrant per generation. However, since the genetic dividend of immigration was probably too optimistic assuming complete genetic uniqueness of the immigrants, two further models were developed to better utilize the genetic data available.The first of these two models used supplementation as before, but this time using pedigree data and individual inbreeding coefficients for a sample of the population in 2012. The second model used allele frequencies that were estimated from genetic marker data from the population in 2012, and for the most proximate immigrant (Finnish) population, and used these genetic data to simulate changes in genetic diversity under different dispersal scenarios. It was not possible to combine these two approaches in a single model using Vortex, so their outputs were compared and contrasted but more emphasis has been placed on the allele frequencies based model. The allele frequencies based model showed that modest levels of immigration (one effective migrant per six years or 0.83 per generation) over both a ten and twenty generation period was sufficient to maintain gene diversity at acceptable levels (0.95 of its current state), regardless of the population size when it was varied between 300 and 700, and was able to constrain mean inbreeding coefficient in the population to values below 0.31 (current estimate 0.27). This result is conservative in the sense that it is predicated on the assumption that immigrants have similar reproductive success to residents (there is circumstantial evidence that immigrant can outperform residents). However, ‘effective’ immigration implies individuals that arrive in the population survive and breed and this has been a rare occurrence in the Scandinavian wolf population since its reestablishment during the last thirty years. For the long-term survival of the Scandinavian wolf and to conform to Favourable Reference Population status, an effective population size of 500 should be achieved for the meta-population to which it belongs and the current effective size of the Scandinavian wolf is between 80 and 130. It is therefore important to establish the fraction of the entire metapopulation’s effective size (including Finland and Karelia) that is represented in Scandinavia so that appropriate targets can be established.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)

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