Finding Biodiversity Hotspots

Reading the lay of the land can lead biologists to biodiversity hotspots. Landscapes with great variation in slope, soil, and other characteristics tend to shelter more species than do featureless areas, according to two studies appearing in the current issue of Conservation Biology. The findings could lead to faster, cheaper ways to earmark areas in need of conservation.

Biologists have long speculated that highly diverse landscapes such as mountain ranges host more species. Proving the connection--although requiring back-breaking, time-consuming field surveys--would provide conservationists with an easier way to locate species-rich hotspots.

One promising shortcut that uses digital maps was recently tested by biologists Peter August, Keith Killingbeck, and colleagues at the University of Rhode Island, Kingston. The team used a geographic information system to analyze the topography, soils, and hydrology of 234 2-hectare plots within a Rhode Island reserve. They then went out into the field and counted the trees and shrubs growing on 20 of both the most diverse and least diverse plots. On average, complex plots had more species: 31 versus 18. To see if the method worked in different kinds of landscapes, they then tried it on 26 reserves--including salt marsh and grassland habitat--owned by the Rhode Island Audubon Society and got similar results. Killingbeck, however, cautions that the approach still needs to be tested elsewhere and notes that it does not necessarily identify areas holding rare or valued species.

Although the approach is "not radically new, it is a very useful step toward understanding how the physical environment affects species diversity," says conservation biologist Malcolm Hunter of the University of Maine, Orono. And August notes that conservation groups have already "expressed big interest in the concept."