During the past decade, voluntary contracts called conservation easements have become a popular method for conserving land. Embodied in an agreement between landowners and a government or non-governmental organization, these easements have differing goals, structures and financial arrangements.

As the area protected by easements has grown to 30 million acres, questions have multiplied. Are easements the most efficient way to conserve land and biodiversity? What easement structures are the most effective?

The answers are difficult to obtain, says Adena Rissman, an assistant professor in forest and wildlife ecology at the University of Wisconsin-Madison, who began exploring easements about 10 years ago.

"It's become clear that easements are not going to be easy to assess, compared to common park or wilderness area models, given the diverse goals, processes, and financing," Rissman says.

In a study published in late September in the journal Society and Natural Resources, Rissman and Nathan Sayre of the University of California compared two large easement projects dominated by grazing land: the Malpai Borderlands Group, straddling the Arizona-New Mexico border, and The Nature Conservancy's Lassen Foothills, in northern California.

Each project has more than 80,000 acres under easements, but they have differing origins, structures and conservation requirements, Rissman says. The borderlands project was intended to preserve habitat for the ranchers who had sold easements to a land trust that they control. The foothills easements are held by The Nature Conservancy, which helped fund Rissman's research and has explicit biodiversity conservation goals.

Although Rissman has long been interested in the efficacy of easements, her goal in this study was to explore the social relationships that helped or hindered progress, using interviews with landowners, conservation organizations, and scientists.

Social relationships, she says, affect the nature, terms and methods of the easement agreement, even when the easements have broadly similar goals in conserving grazing land.

"In comparing the two cases, we assumed that landowner goals and land trust goals were more closely aligned for Malpai than for Lassen, since in Malpai, landowners make up the majority of the land trust board," Rissman says.

"So we expected to find that the Malpai easements would contain fewer restrictions, that the restrictions would be behavior-based rather than performance-based, and that the monitoring would be less intensive, and this matches pretty closely what we found."

Also as expected, Rissman adds, Lassen contained a greater focus on direct conservation outcomes.

The surprising thing, Rissman says, was "the important role of informal, personal relationships. These were a stronger driver of conservation outcomes in Malpai, where ranchers were working together to raise funds for research and land management."

The tight social relationships at Malpai Borderlands existed long before the easements were written, Rissman says.

"Malpai is a unique organization created by a unique confluence of events, a longstanding effort to bring together the landowners to support their relations with governmental agencies that own a great deal of land in the region, and from which the ranchers lease large areas," Rissman says.

The Lassen project is more typical, with diverse landowners, and the easement process tended to strengthen social relationships that were looser to begin with, Rissman says.

"The existing social situation of each area helped determine how the land trust worked with landowners, and that affected the ability to meet conservation goals. Malpai was more concerned with preserving the grazing character of the land, and its major outcome was to limit building; the easements contained few restrictions on how ranchers managed their land."

Beyond restricting development, the Lassen easements prohibited the scraping and collection of volcanic rock from the grasslands, and required some landowners to install cattle-proof fences along streams to reduce erosion and water pollution. Lassen also had an enforceable requirement that landowners retain a certain amount of stubble through the winter to prevent erosion.

Particularly at Malpai, having outside advice and expertise was key to success, Rissman says. "Consultants and scientists participated; this was not a do-it-yourself project."

As far as can be told, both projects are meeting their goals, which reflects both a workable structure and effective management of social relationships, Rissman says.

"When we design and evaluate conservation programs, we need to pay close attention to these relationships, both formal and informal. Land managers need to account for more than just trees and birds. This is not just about resources, it's also about managing relationships among people."