An impact evaluation of conservation investments targeting long-distance migratory species.

Abstract

We evaluated the impact of a philanthropic program investing in the conservation of sites along the Pacific Americas Flyway, which spans >16,000 km of coastline and is used by millions of shorebirds. Using a quasi-experimental, mixed methods approach, we estimated what would have happened to shorebird populations at 17 sites without the sustained and additional investment they received. Using the synthetic control method, we failed to find evidence of an overall effect across three outcome variables. Species- and site-level effects were heterogeneous, with a few cases showing some evidence of a positive effect, including a site with a high level of overall investment. Results suggest six shorebirds are declining across the entire Flyway, including at many Latin American sites. However, the percentage of Flyway populations present at the sites has remained stable, with a greater percentage at the treatment sites (i.e., investment sites). Multiple mechanisms are possible for our results, including that investments have yet to mitigate impacts and negative impacts at other sites are driving declines at the treatment sites. A limitation of our evaluation is the sole focus on shorebird abundance and lack of data that prohibited the inclusion of other outcome variables. Monitoring infrastructure is now in place to design a more robust and a priori shorebird evaluation framework across the entire Flyway. With this framework, it will prove easier to prioritize limited dollars to result in the most positive conservation outcomes. This article is protected by copyright. All rights reserved.