Elevation and connectivity define genetic refugia for mountain sheep as climate warms

Global warming is predicted to affect the evolutionary potential of natural populations. We assessed genetic diversity of 25 populations of desert bighorn sheep (Ovis canadensis nelsoni) in southeastern California, where temperatures have increased and precipitation has decreased during the 20th century. Populations in low‐elevation habitats had lower genetic diversity, presumably reflecting more fluctuations in population sizes and founder effects. Higher‐elevation habitats acted as reservoirs of genetic diversity. However, genetic diversity was also affected by population connectivity, which has been disrupted by human development. Restoring population connectivity may be necessary to buffer the effects of climate change on this desert‐adapted ungulate.

[1]  G. L..  North America , 2022, Nature.

[2]  Rob Roy Ramey,et al.  Highways block gene flow and cause a rapid decline in genetic diversity of desert bighorn sheep , 2005 .

[3]  B. Charlesworth,et al.  NEUTRAL GENETIC DIVERSITY IN A METAPOPULATION WITH RECURRENT LOCAL EXTINCTION AND RECOLONIZATION , 1999, Evolution; international journal of organic evolution.

[4]  I. Hanski,et al.  Inbreeding and extinction in a butterfly metapopulation , 1998, Nature.

[5]  M. Bhaskara Rao,et al.  Model Selection and Inference , 2000, Technometrics.

[6]  V. Bleich,et al.  Mountain Sheep in California: A Historical Perspective on 108 Years of Full Protection , 1987 .

[7]  Pieter Baas,et al.  Effects of climate change on biodiversity: a review and identification of key research issues , 1999, Biodiversity & Conservation.

[8]  D. Ebert,et al.  Genetic Diversity and Genetic Differentiation in Daphnia Metapopulations With Subpopulations of Known Age , 2005, Genetics.

[9]  M. Hossaert-McKey,et al.  Genetic diversity and reproductive success in mandrills (Mandrillus sphinx). , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[10]  François Rousset,et al.  GENEPOP (version 1.2): population genetic software for exact tests and ecumenicism , 1995 .

[11]  J. Goudet.  FSTAT (Version 1.2): A Computer Program to Calculate F-Statistics , 1995 .

[12]  L. Bernatchez,et al.  Adaptive evolutionary conservation: towards a unified concept for defining conservation units , 2001, Molecular ecology.

[13]  D. Foran,et al.  The relationship between genetic variability and growth rate among populations of the pocket gopher, Thomomys bottae , 2003, Conservation Genetics.

[14]  W. Etges,et al.  Climate change and recent genetic flux in populations of Drosophila robusta , 2005, BMC Evolutionary Biology.

[15]  R. Frankham.  Genetics and conservation biology. , 2003, Comptes rendus biologies.

[16]  D. McCullough,et al.  Effects of Climate Change on Population Persistence of Desert‐Dwelling Mountain Sheep in California , 2004 .

[17]  Time series analyses of global change data. , 1994, Environmental pollution.

[18]  O. Hoegh‐Guldberg,et al.  Ecological responses to recent climate change , 2002, Nature.

[19]  R. Lande.  Genetics and demography in biological conservation. , 1988, Science.

[20]  V. Bleich,et al.  Genetics and the conservation of mountain sheep ovis canadensis nelsoni , 1986 .

[21]  G. Yohe,et al.  A globally coherent fingerprint of climate change impacts across natural systems , 2003, Nature.

[22]  L. Bender,et al.  Precipitation, density, and population dynamics of desert bighorn sheep on San Andres National Wildlife Refuge, New Mexico , 2005 .

[23]  R. Moss,et al.  The regional impacts of climate change : an assessment of vulnerability , 1997 .

[24]  P. Leberg,et al.  Estimating allelic richness: Effects of sample size and bottlenecks , 2002, Molecular ecology.

[25]  M. Whitlock,et al.  The effective size of a subdivided population. , 1997, Genetics.

[26]  J. Berger,et al.  Persistence of Different‐sized Populations: An Empirical Assessment of Rapid Extinctions in Bighorn Sheep , 1990 .

[27]  Jay L. Lush,et al.  The genetics of populations , 1948 .

[28]  James H. Brown,et al.  Using Montane Mammals to Model Extinctions Due to Global Change , 1992 .

[29]  R. Levins.  Some Demographic and Genetic Consequences of Environmental Heterogeneity for Biological Control , 1969 .

[30]  G. Luikart,et al.  Genetic rescue of an insular population of large mammals , 2006, Proceedings of the Royal Society B: Biological Sciences.

[31]  J. Wehausen.  Rapid Extinction of Mountain Sheep Populations Revisited , 1999 .

[32]  J. P. Mccarty.  Ecological Consequences of Recent Climate Change , 2001 .

[33]  J. Peñuelas,et al.  Running to stand still: adaptation and the response of plants to rapid climate change. , 2005, Ecology letters.

[34]  B. Charlesworth,et al.  Effects of metapopulation processes on measures of genetic diversity. , 2000, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[35]  R. Shaw,et al.  Range shifts and adaptive responses to Quaternary climate change. , 2001, Science.

[36]  Boris Worm,et al.  Ecosystem recovery after climatic extremes enhanced by genotypic diversity. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[37]  Uma Ramakrishnan,et al.  Genetic Response to Climatic Change: Insights from Ancient DNA and Phylochronology , 2004, PLoS biology.

[38]  R. R. Ramey,et al.  Experiments in DNA extraction and PCR amplification from bighorn sheep feces: the importance of DNA extraction method. , 2004, The Journal of heredity.

[39]  J. Gamarra,et al.  Metapopulation Ecology , 2007 .

[40]  James K. Lindsey,et al.  On the use of corrections for overdispersion , 1999 .

[41]  J. Wehausen,et al.  Desert-dwelling Mountain Sheep: Conservation Implications of a Naturally Fragmented Distribution , 1990 .

[42]  P. Leberg,et al.  GENETIC APPROACHES FOR ESTIMATING THE EFFECTIVE SIZE OF POPULATIONS , 2005 .

[43]  R. Frankham.  Relationship of genetic variation to population size in wildlife , 1996 .