Essays on Protected Area Size: Effects on Ecological and Economic Effectiveness

Faced with continuing threats to biodiversity, governments are increasingly seeking to expand protected areas. Financial resources are limited, which often spurs conservation planners to prioritize locations for future protection. Thus, prioritization of protected areas is increasingly being evaluated based on the return on investment (ROI) they offer. This thesis consists of two essays analyzing the land acquisitions made by the world’s largest conservation organization, The Nature Conservancy (TNC). In the first essay, entitled “Effects of Protected Area Size on Conservation Return on Investment,” the increase in effective mesh size per dollar invested to acquire a parcel was greater for larger parcels, implying that the overall ecological and economic effectiveness is higher in protecting larger areas relative to smaller ones. This finding suggests that, all else being equal, conservation organizations have an incentive when selecting parcels for protected area creation to favor larger parcels over smaller ones. Furthermore, given the incentive to favor larger parcels, conservation organizations tend to favor larger parcels more as is the case when they focus on both ecological and economic effectiveness together and not on ecological effectiveness alone. Therefore, a conservation priority decision will be biased toward larger parcels if conservation organizations are interested in achieving ecological and economic effectiveness.

The second essay, entitled “Effects of Parcel Size on Conservation Return on Investment for Protected and Unprotected Matching Sites,” provides the first rigorous test of and comparison of the elasticity of size on conservation ROI with area between transactions made by a conservation organization versus transactions without such involvement. This comparison shows that a conservation organization’s scale effects with protected area size on conservation benefit and cost are not shown in non-conservation acquisitions in the wider land market. This finding implies that different preferences lead to scale effects with protected area size on conservation benefit and cost as the general market behavior of the non-conservation buyers does not result in the same scale effects for unprotected sites.