Environmental correlates of avian species richness over southern Ontario, Canada.

Species richness is an ecologically important descriptor of ecosystems and, as a component of biodiversity, may be useful for conservation planning. Global and local patterns of richness have been related, with moderate success, to climatic and habitat parameters respectively. However our ability to predict species richness breaks down at intermediate scales (quadrats 10$\sp0$-10$\sp3$ km$\sp2$ in size extending over regions of 10$\sp3$-10$\sp6$ km$\sp2$). We examined the spatial variation in breeding bird species richness in 100 km$\sp2$ squares, across 200,000 km$\sp2$ of southern Ontario, and tested for relationships with a suite of environmental variables that included, climate, human population, land cover, a heterogeneity index, soil fertility and parkland. We conclude that at this spatial scale, the variation in total avian species richness over southern Ontario is not sufficiently well related to either temperature or habitat to warrant further investigation of possible mechanistic links. The richness of certain guilds, however, shows some promise as a possible measure for conservation planning and management. (Abstract shortened by UMI.