Prioritising species for monitoring in a South African protected area and the Red List for plants

Abstract

Protected areas (PA) in biodiversity hotspots face the challenge of monitoring large numbers of locally rare and threatened plant species at times with limited budgets. Prioritising species according to their local extinction risk could help PA managers to decide which species to monitor. However, there is often very little information available on the species occurrence and extinction risk in the PA. Because of this, PA managers often rely on the national or global Red List for prioritising species at the PA level. Here, we evaluate the effectiveness of using the Red List for species prioritisation and examine the robustness of extinction probability equations for 74 fynbos species in Table Mountain National Park (TMNP). We conducted in-field surveys to verify the persistence of subpopulations previously recorded, following a detection protocol adapted for rare and cryptic plant species. We found that most targeted species were extant within TMNP but with a substantially reduced number of subpopulations. Twenty-six species only had one or two subpopulations remaining. Critically Endangered (CR) species lost on average 4 subpopulations more than Least Concern (LC) species. However, species persistence in TMNP was largely independent of their Red List status. Half of the species represented by just one or two subpopulations were listed as LC. This work shows that prioritising monitoring according to the Red List status is not appropriate at the scale of the individual PA. We suggest that more in-field data and monitoring is required to prevent extinctions occurring in PAs.