Background/Question/Methods: It is becoming increasingly obvious that preserving native biodiversity can help reduce the risk of zoonotic diseases, yet the benefits of disease cases averted are rarely considered when the economics of habitat protection or restoration are considered. We present a cost/benefit analysis for an extensive habitat restoration plan in the Albany Pine Bush Preserve (APB), New York. The APB is a rare, inland, pitch pine/scrub oak community. Parts of the site are degraded by invasive species including the black locust (Robinia pseudoacacia), a nitrogen fixing tree that disrupts the soil chemistry and facilitates further invasion by other species. An ambitious plan to restore this habitat has been challenged on economic grounds.
Our cost/benefit analysis included as a benefit, the value of the cases of Lyme disease (LD) likely to be averted by the reduction in the density of black-legged tick (Ixodes scapularis), the vector of LD. We documented that the restoration efforts reduce the density of the infective stages of the black-legged tick by more than 98%. We then used published cost of illness studies to estimate the direct and indirect costs of LD.
Results/Conclusions: From published accounts, we established a cost of $8,402 per LD case. We then calculated the present value, the estimated amount that a case of LD per year, prevented in the future, is worth today given a specified discount rate (3%). Thus, preventing one case of LD per year has a present value (PV) due to avoided direct and indirect costs of treatment of $280,067. The costs of the restoration efforts (the removal of trees, disking soil to dilute nitrogen-enrichment, planting native species, herbicide treating root sprouts (one-time cost of $2,959,588) and burning every 5 years to discourage woody growth ($2,780,000/5 years)), have a PV of $23,193,778. Thus, the costs of the habitat restoration efforts can be recouped by preventing 83 LD cases per year.
Based on the LD rate in Albany County, NY (213 cases per 100,000 people), the number of visitors per year to the APB (100,000) and the reduction in tick density caused by the restoration (98%), we estimate that the restoration project could prevent up to 200 LD cases per year, more than covering the costs of restoration. Although not all restoration efforts will result in a similar reduction in zoonotic disease risk, the possibility should be considered when weighing the costs and benefits of restoration and preservation.