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Citation. Chapman, K. 2001. Conserving regional biodiversity: role of reserves, rural lands and suburbs in the prairie-forest transition, Minnesota, USA. Ph. D. Thesis, University of Minnesota.
Abstract. Increasing land use intensity in the prairie-forest transition, Twin Cities, Minnesota, raises concerns
that species might disappear from the regional biota. Bird, tree, and shrub species' responses to land
use intensity (in reserves, rural lands, suburbs) and canopy cover (from grassland to forest) were
measured in 302 plots to understand how communities or species simultaneously varied along gradients. Unexpectedly, bird richness and diversity in plots were equal at all land use intensities, while the rural landscape supported the greatest bird richness and diversity, and reserves slightly less. Bird richness fell 38% and beta diversity 45% from rural lands to suburbs. However, rural lands supported fewer species of woody plants than reserves and suburbs, although higher suburban richness was due to non-native species. Suburban grasslands and savannas had very low shrub abundance and very high non-native bird abundance, and suburban forests supported unexpectedly high numbers of development tolerant native birds. The bird communities of reserve and rural forests were more similar than were reserve and rural grasslands/savannas. Management sensitive birds preferred reserves, and regionally declining birds occurred largely in grasslands. Of 63 bird species analyzed in detail, one-fifth required reserves, two-fifths tolerated agriculture but not suburbanization, and 29% benefited
from suburbanization. Life history traits associated with birds using grassland and savanna resembled life history traits of birds occupying suburbs, indicating that grassland and savanna birds possessed traits better suited for colonizing the unique suburban environment than did forest birds. As landscapes became increasingly human dominated, forest birds became increasingly restricted to forests. However, grassland and savanna birds were more vulnerable than forest birds because regional grassland-savanna loss and use intensity were greater than forest loss and use. Reserves may best serve as refuges for regionally declining grassland and savanna birds, while suburbs could support large populations of development tolerant native birds if development were concentrated and large expanses of wild land retained. Rural lands represented an unrecognized conservation opportunity threatened by dispersed residential and suburban-style development. Conservation measures in rural lands could increase the likelihood that most members of the regional biota would persist well into the