"Until recently, conservation buyers were a very small part of the land market--they didn't have much impact," says Gretchen Daily, professor of biological sciences at Stanford University and co-author of the study. "But now there are over 1,500 land trusts operating in the United States, and together they can change land prices and patterns of development."
The full or partial purchase of land has become a cornerstone of efforts to conserve biodiversity in countries with strong private property rights, the authors write, but harm arises when land trust activity elevates land prices and displaces development onto lands where conservation is needed.
"Land trusts have become so powerful that their collective purchases could actually backfire by drawing development toward sites with high conservation value," Daily explains. "Protecting lands that lack biodiversity is not only a waste of money but undermines future opportunities by increasing development pressure on unprotected lands."
For the study, lead author Paul Armsworth of Sheffield University, Peter Kareiva of The Nature Conservancy, James Sanchirico of Resources for the Future and Daily conducted an economic analysis of land-buying practices based on a variety of assumptions about where biodiversity resides. They found that market feedbacks can be especially worrisome if lands outside of nature reserves have considerable ecological value, and if there are developers keen to capitalize on amenities that result from conservation.