Private Land And Public Good: A Study In Bird Conservation
Growing food now takes up 38% of land worldwide. This change in land use has reduced wildlife habitat, leading to population declines in many species. This study examined how well private land conservation programs work to reverse these declines in four bird species in Illinois.
The North American Breeding Bird survey made its first counts in 1966. Over time, tallies for many bird species have declined, some precipitously. In response, continent-wide goals were set that would return populations to pre-decline levels over the next 30 years. These goals were further refined into regional and statewide targets.
Much of the restoration effort has focused on expanding breeding habitat. However, buying and restoring substantial amounts of land is economically infeasible. Instead, conservation programs in both Europe and the U.S. financially incentivize farmers to create wildlife habitat on their farms. In the U.S., the Conservation Reserve Program (CRP) and the Wetlands Reserve Program (WRP) have created three million acres of potential wildlife habitat out of private farmlands.
The study sought to quantify the how much private land conservation programs contributed to population recovery. It focused on four bird species whose populations have declined at least 50% since 1966. They were the Bell’s Vireo, Field Sparrow, Northern Bobwhite and Willow Flycatcher. Investigators also estimated what it would cost to achieve population goals for the four species.
Researchers surveyed for birds in 172 randomly-chosen restored fields in central and west-central Illinois from 2012 to 2015. Population abundance for each of the four species was then estimated from these samples. Where the population estimate fell short of the population goal, researchers calculated the amount and cost of land needed to reach the species goal. Results showed that three of the four species, Field Sparrow, Northern Bobwhite and Willow Flycatcher would need additional restored habitat to reach population goals. The cost would be millions of dollars per year just in land rental alone without including outlays for habitat creation or management.
These results suggest that programs such as CRP are effective for restoring the density of species with modest population goals. For species with goals far above the current populations, the amount of habitat needed would be difficult to obtain and cost-prohibitive. In this study, private land conservation efforts were adequate to restore the Bell’s Vireo population to the statewide goal and the Willow Flycatcher close to the statewide goal. However, restored habitats are supporting populations of the Field Sparrow and Northern Bobwhite that are less than one-third of the statewide goal.
Improving the management of restored habitats may be successful in improving population densities. Targeting these efforts towards at-risk species would be a cost-effective way to improve results. Animal advocates can use these results as a guide to focus their efforts on the species most likely to be impacted within the existing conservation programs.