Keystone species complexes in kelp forest ecosystems along the northern Chilean coast (SE Pacific): Improving multispecies management strategies

Abstract

Focal species help us understand composition, status and function at the community and ecosystem levels. Multispecies trophic network analysis extends the classic concept towards a more holistic view, based on the concept of the “keystone species complex” (KSC). The main goal of this study is to determine the keystone species complex in seven benthic ecological systems dominated by kelp forests along approximately 1000 km of the northern Chilean coast. For this purpose, quantitative and semi-quantitative multispecies trophic network models were constructed. In addition, the obtained KSCs were compared to those obtained in previous studies to determine the general pattern among the linked components. Based on our outcomes, we can state the following four generalities: (1) the KSCs are constituted of components of three trophic levels; (2) the components are directly and trophically linked; (3) the trophic path consisting of the sea star M. gelatinosus (top predator), the Small Epifauna Omnivores and Phytoplankton (primary producer) appears in most of the model systems; and (4) the KSCs reached an average of 17.3% of the total system biomass. The determination of KSCs along intervening coastal ecosystems could improve the management strategies for artisanal fisheries and conservation-monitoring programmes.