Using forest-based carbon programs to conserve biodiversity
While the main impetus for carbon program creation is the mitigation of carbon pollution, these programs may also provide conservation benefits including habitat preservation for threatened species. Owners of small forest tracts, however, may be unlikely to enroll in carbon programs because profits from small tracts may not compensate for the fixed costs of carbon plan development and verification. As a result, a significant proportion of forests may be excluded from forest-based carbon programs. A potential solution is for third party vendors, such as conservation organizations, to aggregate smaller parcels for enrollment. We investigated whether aggregating parcels for carbon program enrollment might provide conservation co-benefits in the form of conserved habitat for rare species. To do so we assessed whether forest parcels enrolling in carbon programs encompass a significant number of rare species. First, we gathered data on parcel size enrollment in three carbon registries and evaluated whether the distribution of forest-tracts enrolled in carbon projects is similar to the distribution of forest-tracts across the US. We then examined how the distribution of rare species correlates with the distribution of enrolled parcel sizes by overlaying spatially explicit species observation data with forest parcel data for five focal states.
We found that the majority of US forest parcels are smaller than that enrolled in existing carbon programs and that the distribution of rare species on parcels reflects parcel size with a slight skew toward more rare species found on small parcels. As such, the vast majority of rare species are on small parcels. Our findings suggest that enrollment of only large parcels in carbon programs will be inefficient at providing conservation co-benefits, and that conservation organizations would be well served to act as aggregators of smaller parcels for enrollment thus offsetting costs of protecting valued resources not found on large tracts.