Unpacking conservation easements’ assessed land use designations and their implications for realizing biodiversity protection

Native ecosystem and biodiversity loss from land use conversion into human-modified landscapes is evident in the U.S. and globally. In addition to public land conservation, there is an increase in private land conservation through conservation easements (CEs) across exurban landscapes. Not every CE was established strictly for biodiversity protection and permitted land uses can increase human modification. No research of which we are aware has examined the actual tax assessor’s land use designations (LUDs) through time. We constructed granular CE datasets (GCED) of CEs and their parcels’ tax assessment LUDs for 1997 – 2008/2009, based on original data from twelve counties in six U.S. states. Using the GCED, we examined patterns in the LUDs, with implications for land uses that could impact CE biological outcomes. We show that LUDs on exurban private conservation lands were predominately residential and agricultural, with increased residential over time. Critically, the LUDs lack a biological conservation exempt designation/category. There is no consistent trend in association between the primary CE reason and its parcel’s LUD, suggesting that they coincide in some circumstances but in others, the CE may be a response to contravene the LUD. The majority of the first CE reasons are focused on open space preservation, except in some counties where agricultural land uses and agricultural CEs are associated. The economically and human-focused LUD is one of many social factors that should be considered in a classification system for private land conservation and CEs more specifically. These results prompt the land conservation, conservation biology, and environmental planning communities to explore assessed land uses’ impact on biodiversity conservation objectives.