Land trusts and conservation easements: Who is conserving what for whom?

Land trusts, partnered with government agencies or acting alone, are working to conserve habitat, open space, and working landscapes on private land. Spending both public and private funds, such institutions frequently acquire less than full title by purchasing or accepting donations of conservation easements. These title and organizational arrangements are evolving so fast that it is difficult to assess their conservation accomplishments and long-term viability. To understand the contribution of these arrangements to the preservation and restoration of biodiversity, conservation biologists need to identify the biological resources likely to be conserved and those likely to be left unprotected through easements held by land trusts. We describe land trusts and conservation easements and why they are currently an attractive approach to land protection. Our review of the literature showed that little information is available on (1) the resulting pattern of protected lands and resources being conserved, (2) the emerging institutions that hold conservation easements and the landowners they work with, and (3) the distribution of costs and benefits of land trusts and easements to communities and the general public. The prescriptive literature on how to establish land trusts and negotiate easements is extensive. However, easily available information on protected resources is too aggregated to determine what is actually being conserved, and more detailed data is widely scattered and hence difficult to synthesize. The social science literature provides some insight into the motives of landowners who participate but offers little about the variety of institutions or which type of institution works best in particular ecological and political settings. Equally undeveloped is our understanding of the inherent tension between the public and private benefits of this widely used incentive-based conservation strategy. Interdisciplinary research is needed to determine the ecological and social consequences of acquiring partial interest in private land for conservation purposes.