Human disturbance on macrobenthic assemblages and the role of Marine Protected Areas in reducing its impact.

Abstract

Marine protected areas (MPAs) are areas in the coastal zone of land or seas especially dedicated to protection and maintenance of biological diversity, and are currently receiving increasing attention as management tools for protecting marine populations from destructive human activities. The present study explores the impact of a marine protected area (MPA) in Sri Lanka on a gradient of anthropogenic disturbances on rocky shore communities by comparing the benthic communities of disturbed and non-disturbed localities. This paper assessed the ecological impacts of unconstrained human activities in two study localities and compared with one non-exploited locality. Results showed that community abundance followed a decreasing trend along gradients with increasing disturbances, albeit community biomass, due to opportunistic algal species, increased parallel to disturbances. The community compositions in the three study localities differed, ranging from a predominantly conservative species to fast-growing opportunistic species in disturbed areas. A combination of multivariate analyses confirmed that most of the species with dominant biomass in disturbed areas were opportunistic species such as Valoniopsis pachynema, Gracilaria cassa and Padina boergesenii. Our study supports the growing literature that human activities in the coastal zone modify the original community assemblage structure.