"Our findings suggest that alteration and destruction of the remaining productive habitats outside nature reserves will pose dire threats to many wildlife populations," say Andrew Hansen and Jay Rotella of Montana State University in Bozeman in the August issue of Conservation Biology.
Globally, development is concentrated near biodiversity hotspots. This is partly because private lands are more likely to have productive habitats such as lowlands and coastal and riparian areas, which generally have moderate climates, ample water and fertile soil. In contrast, reserves are more likely to be at higher elevations and have poor soil, which makes them less productive. This disparity means that species in a reserve may depend on the more productive habitat on nearby private lands, making the species vulnerable to development outside the reserve.
Hansen and Rotella studied the effects of land use and habitat type on bird populations in the Greater Yellowstone Ecosystem (GYE), where rural residential development has increased rapidly. Development has increased more than four times since 1970 in the Montana and Wyoming parts of the GYE. The 3,600-square mile study area ranged from a high-elevation plateau in Yellowstone National Park to privately-owned lowlands. The researchers assessed bird abundance and diversity at 100 sites that represented the study area's range of topography, climate and soils. 135 bird species were found in the study area, and sites estimated to have 60% or more of the maximum bird abundance and diversity were designated "bird hotspots". The researchers also assessed the reproduction and population growth of American robins and yellow warblers at two types of sites: low-elevation cottonwood stands and
Contact: Andrew Hansen
Society for Conservation Biology