Conservation of peripheral populations
My research has focused on the ecology of Canada lynx (Lynx canadensis), a mammal experiencing substantial range contraction across North America. I have identified threats to lynx populations at their southern range extent, including hybridization with bobcats (Lynx rufus), riverine barriers, and gradients of climate and suitable habitat.
Continental-scale assessment of the hybrid zone between bobcat and Canada lynx
The distribution of Canada lynx in North America has contracted by 40% from its historical range, and hybridization with bobcats is a potential, uncertain threat to lynx conservation. We conducted a continental-scale assessment of the prevalence of hybridization and genetic introgression between lynx and bobcat. Using control region sequences and clustering of microsatellite data, we found that the prevalence of genetic introgression was relatively low. We found evidence of backcrossing to both lynx and bobcat parental types, suggesting that hybrids can be fertile. If the abundance of Canada lynx at the southern extent of its distribution is low relative to bobcat, hybridization and backcrossing with bobcat over several generations could result in the loss of lynx in areas of sympatry. If climate warming results in the bobcat distribution shifting northward towards the southern extent of the lynx distribution, the likelihood of interspecific hybridization could increase.
Isolation of peripheral populations of Canada lynx
We tested whether the St. Lawrence River in eastern Canada would cause genetic divergence of Canada lynx populations by restricting dispersal and gene flow. We sampled lynx from eastern Canada and found three genetic clusters, defined by the St. Lawrence River and the Strait of Belle Isle, a waterway separating Newfoundland from mainland Canada. These waterways were not absolute barriers, however, as we found 24 individuals that appeared to have crossed them. Peripheral populations of lynx are threatened in parts of Canada and the USA, and it is thought that these populations are maintained by immigration from the core. Our findings suggest that in eastern North America, rescue might be less likely because the St. Lawrence River restricts dispersal. We found that ice cover was often sufficient to allow lynx to walk across the ice in winter. If lynx used ice bridges in winter, then climate warming could cause a reduction in the extent and longevity of river and sea ice, further isolating these peripheral lynx populations.
Climate change reduces genetic diversity of Canada lynx at the trailing range edge
Shifts in species distributions due to environmental change may affect the spatial pattern of genetic structure within a species' range. We investigated spatial patterns of neutral genetic diversity and differentiation at the southern edge of the Canada lynx distribution in Ontario, Canada. We showed that the southern range boundary of lynx distribution in central Canada has contracted northward by >175 km since the 1970s, and that high winter temperature, low snow depth, and low proportion of suitable habitat are strongly correlated with low neutral genetic diversity and high genetic differentiation at the trailing range edge. Our work demonstrates that environmental conditions can have a marked influence on neutral genetic structure, and suggests that changes in environmental conditions will result in further loss of genetic diversity in southern peripheral populations of lynx.
Publications
Prentice MB, J Bowman, K Khidas, EL Koen, JR Row, DL Murray, PJ Wilson. 2017. Selection and drift influence genetic differentiation of insular Canada lynx (Lynx canadensis) populations on Newfoundland and Cape Breton Island. Ecology and Evolution 7(9): 3281-3294. Link
Koen EL, J Bowman, and PJ Wilson. 2015. Isolation of peripheral populations of Canada lynx. Canadian Journal of Zoology 93(7): 521-530. Link
Koen EL, J Bowman, JL Lalor, and PJ Wilson. 2014. Continental-scale assessment of the hybrid zone between bobcat and Canada lynx. Biological Conservation. 178: 107-115. Link
Koen EL, J Bowman, DL Murray, and PJ Wilson. 2014. Climate change reduces genetic diversity of Canada lynx at the trailing range edge. Ecography 37(8): 754-762. Link
Row JR, PJ Wilson, C Gomez, EL Koen, J Bowman, DH Thornton, and DL Murray. 2014. The subtle role of climate change on population genetic structure in Canada lynx. Global Change Biology 20(7): 2076-2086. Link
Row JR, C Gomez, EL Koen, J Bowman, DL Murray, and PJ Wilson (2012) Dispersal promotes high gene flow among Canada lynx populations across North America. Conservation Genetics 13(5):1259-1268. Link
Continental-scale assessment of the hybrid zone between bobcat and Canada lynx
The distribution of Canada lynx in North America has contracted by 40% from its historical range, and hybridization with bobcats is a potential, uncertain threat to lynx conservation. We conducted a continental-scale assessment of the prevalence of hybridization and genetic introgression between lynx and bobcat. Using control region sequences and clustering of microsatellite data, we found that the prevalence of genetic introgression was relatively low. We found evidence of backcrossing to both lynx and bobcat parental types, suggesting that hybrids can be fertile. If the abundance of Canada lynx at the southern extent of its distribution is low relative to bobcat, hybridization and backcrossing with bobcat over several generations could result in the loss of lynx in areas of sympatry. If climate warming results in the bobcat distribution shifting northward towards the southern extent of the lynx distribution, the likelihood of interspecific hybridization could increase.
Isolation of peripheral populations of Canada lynx
We tested whether the St. Lawrence River in eastern Canada would cause genetic divergence of Canada lynx populations by restricting dispersal and gene flow. We sampled lynx from eastern Canada and found three genetic clusters, defined by the St. Lawrence River and the Strait of Belle Isle, a waterway separating Newfoundland from mainland Canada. These waterways were not absolute barriers, however, as we found 24 individuals that appeared to have crossed them. Peripheral populations of lynx are threatened in parts of Canada and the USA, and it is thought that these populations are maintained by immigration from the core. Our findings suggest that in eastern North America, rescue might be less likely because the St. Lawrence River restricts dispersal. We found that ice cover was often sufficient to allow lynx to walk across the ice in winter. If lynx used ice bridges in winter, then climate warming could cause a reduction in the extent and longevity of river and sea ice, further isolating these peripheral lynx populations.
Climate change reduces genetic diversity of Canada lynx at the trailing range edge
Shifts in species distributions due to environmental change may affect the spatial pattern of genetic structure within a species' range. We investigated spatial patterns of neutral genetic diversity and differentiation at the southern edge of the Canada lynx distribution in Ontario, Canada. We showed that the southern range boundary of lynx distribution in central Canada has contracted northward by >175 km since the 1970s, and that high winter temperature, low snow depth, and low proportion of suitable habitat are strongly correlated with low neutral genetic diversity and high genetic differentiation at the trailing range edge. Our work demonstrates that environmental conditions can have a marked influence on neutral genetic structure, and suggests that changes in environmental conditions will result in further loss of genetic diversity in southern peripheral populations of lynx.
Publications
Prentice MB, J Bowman, K Khidas, EL Koen, JR Row, DL Murray, PJ Wilson. 2017. Selection and drift influence genetic differentiation of insular Canada lynx (Lynx canadensis) populations on Newfoundland and Cape Breton Island. Ecology and Evolution 7(9): 3281-3294. Link
Koen EL, J Bowman, and PJ Wilson. 2015. Isolation of peripheral populations of Canada lynx. Canadian Journal of Zoology 93(7): 521-530. Link
Koen EL, J Bowman, JL Lalor, and PJ Wilson. 2014. Continental-scale assessment of the hybrid zone between bobcat and Canada lynx. Biological Conservation. 178: 107-115. Link
Koen EL, J Bowman, DL Murray, and PJ Wilson. 2014. Climate change reduces genetic diversity of Canada lynx at the trailing range edge. Ecography 37(8): 754-762. Link
Row JR, PJ Wilson, C Gomez, EL Koen, J Bowman, DH Thornton, and DL Murray. 2014. The subtle role of climate change on population genetic structure in Canada lynx. Global Change Biology 20(7): 2076-2086. Link
Row JR, C Gomez, EL Koen, J Bowman, DL Murray, and PJ Wilson (2012) Dispersal promotes high gene flow among Canada lynx populations across North America. Conservation Genetics 13(5):1259-1268. Link