Quantifying the contribution of conservation easements to large-landscape conservation

Private lands are critical for conservation of ecosystem diversity and sustaining large-scale ecological processes. Increasingly, conservation easements (CE) are used as a tool to protect private land from future development; yet, few studies have examined whether contemporary patterns of CE effectively contribute to landscape scale biodiversity and ecosystem conservation goals. We analyzed the distribution of 1223 CE established between 1970 and 2016 in the High Divide, a region dominated by public lands and of national conservation importance in the Rocky Mountains of the United States, with respect to ecosystem representation and landscape connectivity, two common large-scale conservation goals. We found that CE were frequently located closer to water and to other land protected for biodiversity (e.g., GAP 1 and 2 status) than were private lands more generally. CE provided increased representation within the protected areas network for 10% of the ecosystems within the region, particularly for mesic and riparian areas. Despite the addition of CE to the protected areas network, we found insufficient representation for 43 out of 87 ecosystems (< 5% representation on land managed for biodiversity). Protection of priority ecosystems varied across CE and illustrated potential mismatches between regional and national scale conservation goals. Furthermore, while public lands contributed the most toward conserving important areas for connectivity, CE protected potential landscape connectivity only slightly more effectively than randomly allocated areas. CE provide important complements to public lands in terms of ecosystem diversity and landscape connectivity. However, conservation planners and land managers could increase conservation benefits from CE by prioritizing under-represented ecosystems and more explicitly targeting lands to maintain landscape permeability.