Potential Sensitivity of Québec's Breeding Birds to Climate Change

We examined the relationship between climatic factors and the distribution of breeding birds in southern Québec, Canada to identify the species whose distribution renders them potentially sensitive to climate change in the study area. We determined the degree of association between the distribution of 65 breeding bird species (601 presence-absence squares of the Atlas of the Breeding Birds of Québec) and climate variables (212 climatological stations in operation for at least 20 years over the period 1953–1984) by statistically correcting for the effects of several factors that are correlated with bird distribution. Factors considered were the nature and scale of land cover patterns that included vegetation types and landscape characterization, geographical coordinates, and elevation. Canonical Correspondence Analysis (CCA) was used to investigate the effect of climatic variables on breeding bird distribution. Independent variables accounted for a total of 29.1% of the variation in the species matrix. A very large portion of the variance explained by climate variables was shared with spatial variables, reflecting the relationships among latitude, longitude, elevation, and climate. After correcting for the effect of land cover variables, climatic variables still explained 11.4% of the variation in the species matrix, with temperature, i.e., warmer summers and milder winters, having a greater influence than precipitation, i.e., wetter summers. Of the 65 species, 14 appeared to be particularly climate-sensitive. Eight are insectivorous neotropical migrants and six species are at the northern limit of their range in the study area. The opposite is largely true for the eight others; they are practically absent from the southern part of the study area, except for the Dark-eyed Junco (Junco hyemalis), which is widespread there. The White-breasted Nuthatch (Sitta carolinensis) is the only resident species that seemed responsive to climatic variables, i.e., milder winters. Climate warming is thus likely to induce northward shifts for several neotropical migrant species. Many species that currently breed in the northern portion of eastern United States are likely to move northward into Canada. It is thus crucial that sufficient habitats be preserved in Canada to accommodate these future “climate refugees.” Forests in the study area are under management for lumber and therefore, their conservation should receive particular attention.