The relative conservation impact of strategies that prioritize biodiversity representation, threats, and protection costs

Edmond Sacre,Rebecca Weeks,Robert L Pressey,Michael Bode

doi:10.1111/csp2.221

Abstract

AbstractDespite exponential increases in the coverage of protected areas (PAs) over recent decades, global biodiversity continues to decline. One explanation for this lack of success is that the efficacy of conservation prioritization strategies is rarely measured in terms of conservation “impact,” which requires comparing proposed PA networks to a counterfactual scenario in which no intervention is applied. This approach contrasts with measuring efficacy using surrogates for conservation impact, such as the extent, total biodiversity value, or representativeness of a proposed PA network. However, implementing an experimental counterfactual scenario is difficult because of time, funding, and ethical constraints. Here, we use an alternative and complementary approach: an ex‐post analysis with counterfactual outcomes measured using historical empirical data on changes in biodiversity in unprotected landscapes. This approach allows for the comparison of different retrospectively implemented prioritization strategies to a real counterfactual outcome. In our analysis, we predict the impact of several alternative PA prioritization strategies in Queensland, Australia, using high‐resolution datasets of vegetation clearing, habitat type, and land acquisition cost. Our results show that achieving conventional conservation targets does not equate to achieving impact, and that alternative, and relatively simple, prioritization strategies can achieve far greater impacts.

Highlights

Despite increasing conservation efforts worldwide, evidence of continued declines in biodiversity (Butchart et al, 2010; Hoffmann et al, 2010; Tittensor et al, 2014) has called into question the efficacy of current conservation prioritization methods (Carwardine, Klein, Wilson, Pressey, & Possingham, 2009; Pressey, Weeks, & Gurney, 2017)
We offer an empirical ex-post approach that allows impacts to be estimated by comparing estimated outcomes to a real counterfactual scenario
Our results illustrate that reaching any specific target does not guarantee that such an approach will lead to benefits in terms of impact, and maximize return on investment

Summary

| INTRODUCTION

Despite increasing conservation efforts worldwide, evidence of continued declines in biodiversity (Butchart et al, 2010; Hoffmann et al, 2010; Tittensor et al, 2014) has called into question the efficacy of current conservation prioritization methods (Carwardine, Klein, Wilson, Pressey, & Possingham, 2009; Pressey, Weeks, & Gurney, 2017). Representation targets are widespread in conservation policy and practice, often serving as the primary objective of national and multinational reserve systems supported by millions of dollars of public and private conservation funding (e.g., Commonwealth of Australia, 2005; Fernandes et al, 2005; UNEP-WCMC, 2008) Many of these approaches disregard an essential component of conservation impact: threats to biodiversity. The second method is to compare alternative prioritization strategies using ex-ante modeling of future landscapes to predict counterfactual outcomes (Monteiro et al, 2020; Newburn, Reed, Berck, & Merenlender, 2005). These are useful for identifying areas for potential protection. We use high-resolution datasets of land valuation to explore the cost-efficiency of each strategy, and to explore how impacts vary according to available budgets

| METHODS

| RESULTS

Findings

| DISCUSSION