Variation in preferences describing how to value the future among conservation practitioners and its implications for today's protection priorities

When seeking to make land conservation decisions, should managers favor actions that will make immediate differences or those promising long-term gains? The choice depends on how individuals weight benefits and costs experienced at different future times, something temporal discount rates can be used to represent. Despite the ubiquity of inter-temporal tradeoffs in conservation decision-making, little is known about time preferences of relevant practitioners. Taking land protection decisions as an example, we use responses from experimental-choice surveys to show practitioners at environmental NGOs display high variability in how they evaluate environmental benefits and costs through time. Participants had a median discount rate of 11.9%, significantly higher than values traditionally used in environmental policy. Moreover, discount rates ranged from 74% to negative values. When asked to compare financial amounts at two future times, practitioners used discount rates that were not significantly different. When asked about an environmental attribute (protected land), they used discount rates that declined through time. We applied such rates to a spatial prioritization model to illustrate how differences we observed in discounting could influence conservation priorities today. We used species persistence in the central and southern Appalachian Mountains as our benefit stemming from protecting land. Through this illustrative application, we show that differences in how practitioners value the future change today's protection priorities, with as little as 43% overlap in counties with the highest conservation return on investment. As the conservation community re-envisions protection goals, how we weight environmental benefits and costs through time will help determine paths forward.