Fig. 2.

Variation in PES enrollment as a function of conservation costs and other enrollment costs. Each panel is an illustrative case. The horizontal axis represents the opportunity costs of conservation and the vertical axis represents other PES enrollment costs. The PES program pays each contract a total of 5, and thus landholders will enroll when their costs fall in the shaded region: the area where the sum of both costs is less than 5. Each dot depicts the costs of 1 of 10 landholders. By construction, six have conservation costs less than or equal to zero and would conserve in the absence of the program. A depicts the case in which there are no costs of enrollment and corresponds to the 10 landholders who enroll at a price of 5 in Fig. 1. B–D focus on these same 10 landholders and depict different correlations between costs of conservation and other costs of enrollment, which yield different enrollment patterns. In each of cases B–D, the average enrollment cost among the 10 landholders is 4.5.