Metrics for evaluating representation target achievement in protected area networks

Global conservation targets (e.g. Aichi Target 11) have helped drive a dramatic expansion of the global protected area (PA) network. Credible metrics have an important role to play in evaluating and expanding PAs to achieve conservation outcomes and objectives. For metrics to be useful and adopted, they need to be transparent, easy to understand, and easy to implement. We present two complementary metrics, mean protection gap and mean target achievement, for evaluating representation target achievement in PA networks along with the R package ConsTarget that calculates and plots both metrics. We use Australia's proposed Commonwealth Marine Reserve network as a case study to demonstrate the application of these metrics. We recommend the metrics be used to evaluate the progress towards building representative PA networks in line with Aichi target 11's goals.