Integrating impact evaluation in the design and implementation of monitoring marine protected areas

Abstract

Quasi-experimental impact evaluation approaches, which enable scholars to disentangle effects of conservation interventions from broader changes in the environment, are gaining momentum in the conservation sector. However, rigorous impact evaluation using statistical matching techniques to estimate the counterfactual have yet to be applied to marine protected areas (MPAs). While there are numerous studies investigating 'impacts' of MPAs that have generated considerable insights, results are variable. This variation has been linked to the biophysical and social context in which they are established, as well as attributes of management and governance. To inform decisions about MPA placement, design and implementation, we need to expand our understanding of conditions under which MPAs are likely to lead to positive outcomes by embracing advances in impact evaluation methodologies. Here, we describe the integration of impact evaluation within an MPA network monitoring programme in the Bird's Head Seascape, Indonesia. Specifically we (i) highlight the challenges of implementation 'on the ground' and in marine ecosystems and (ii) describe the transformation of an existing monitoring programme into a design appropriate for impact evaluation. This study offers one potential model for mainstreaming impact evaluation in the conservation sector.

Keywords: Bird's Head Seascape; Indonesia; conservation impact; coral reefs; counterfactual; monitoring.

Figure 1.

Map of monitoring sites inside and outside of MPAs in the BHS. Triangles indicate sites sampled outside of MPAs (‘control’) and circles indicate sites sampled inside MPAs (‘treatment’). Black shapes were matched and will be included in subsequent impact analyses, while grey shapes are sites that were dropped post-matching and will therefore not be included future impact analyses. Map does not include all MPAs in the region and is limited to MPAs included in the analyses. PNG, Papua New Guinea.

Figure 2.

Baseline differences in the fish biomass of key fisheries (dark blue) and functional fish groups (light blue) within MPAs versus outside MPAs in the BHS, shown as ratios of biomass from matched MPA (inside) and control (outside) site pairs. Ratio more than 0 indicate biomass at MPA sites more than control sites. Each boxplot shows the distribution of ratios for individual MPAs; ratios were also pooled to show the overall distribution across the seascape (All MPAs). The shaded box represents the interquartile range; the black line within the shaded box is the median value; whiskers indicate maximum and minimum values excluding outliers; dots represent outliers (more than 1.5 times upper quartile).