Effects of contrasting types of marine protected areas on seagrass- and coral communities : are community-based reserves an important complement to government-managed protected areas?

Abstract: Coastal ecosystems, including seagrass beds and coral reefs, are among the most ecological and economical important ecosystems on Earth. At the same time as these ecosystems support livelihoods of coastal communities they are being highly degraded worldwide. Government-managed marine protected areas (MPAs) are a common tool in marine conservation and have been demonstrated to successfully protect natural resources. At the same time, they are increasingly criticized for excluding and marginalizing local communities. Therefore, alternative types of management that are managed by the communities themselves (community-based reserves; CBRs) constitute a promising alternative since they have a much higher acceptance among local people. However, the scientific knowledge on protection effects of CBRs on these critical habitats are scarce, and most research on the effects of place-based management has largely focused on coral reefs. The aim of this thesis was therefore to investigate how MPAs and CBRs affect corals and seagrasses, and their associated communities, using coastal Kenya (East Africa) as a case study. Paper I examines effects from CBRs and MPAs on benthic community composition, and cover and diversity of seagrasses, hard corals and associated benthic organisms. Paper II examines the effects of CBRs and MPAs on the density, size, biomass and potential monetary value of fish; the basis for coastal fisheries that are a particularly important ecosystem service in the study area. The results demonstrate that the small and recently protected Kenyan CBRs can increase the diversity of benthic organisms, protect important functional groups, increase structural complexity, and additionally increase fish size, biomass and monetary value. The results also show that protection from MPAs can result in shifts in both seagrass beds and coral reef communities (from a dominance of stress-tolerant species in fished areas, to stress-sensitive species in protected areas), and that the two habitats were similarly affected by protection. In summary, this thesis suggest that i) locally-managed CBRs may be an important complement to MPAs, and ii) that seagrass beds should more often be included in management plans.