Land ownership and other landscape-level effects on biodiversity in southern Ontario's Niagara Escarpment Biosphere Reserve, Canada

摘要

We investigated effects of landscape-level factors on measures of biodiversity using published descriptions for 98 significant natural areas along the Niagara Escarpment. This is a 725 km, largely forested, Paleozoic limestone escarpment that, excepting the Great Lakes, is the most prominent topographical feature of southern Ontario, Canada. Results show highly significant differences in mean site size and extent of forest interior among natural areas of different ownership classes, with larger and more forested sites being under mixed (private + public) ownership, but no significant difference between sites of public and private ownership. Analysis of covariance demonstrated that after controlling for differences in landscape-level factors (total size of natural area, extent of forest interior, extent of landform heterogeneity and geographic location), most measures of biotic diversity (including the number of vegetation community types, provincially rare vascular plants, and regionally and locally rare breeding birds) differed significantly among sites of private, public and mixed ownership. In general, values at public and mixed ownership sites were greatest, with significantly lower biodiversity values at privately-owned sites. Furthermore it would seem not to be a product of public bodies having historically purchased the largest sites or most-forested sites, since there is no significant difference between the mean size of publically-owned and privately-owned sites. Results of stepwise multiple regression confirm the well known relation between size of a natural area and variation in both total, and rare species diversity. Since public sites have generally more species than private sites, they are essential elements of any conservation network.