Linking ecosystem condition and landscape context in the conservation of ecosystem multifunctionality

Abstract

Nature reserves are often implemented to restore the condition of habitats, protect populations of harvested species and to protect, as well as enhance, ecological functions. It is, however, not clear whether and how the spatial context of reserves influences their capacity to promote this ecosystem multifunctionality. We measured how the spatial context of no-take marine reserves and the condition of ecosystems combine to structure animal assemblages and modify rates of two key ecological functions (herbivory, carrion scavenging) in mangrove forests in the Moreton Bay Marine Park, Queensland, Australia. Fish diversity and the abundance of harvested fish species were highest inside reserves, and in mangrove forests nearer to the open ocean and moderate-sized seagrass meadows, and far from coral reefs. The rates of both ecological functions were, however, not elevated inside reserves. The highest rates of carrion scavenging occurred in mangrove forests that were open to fishing, far from the open ocean, and near both large seagrass meadows and coral reefs. Herbivory was highest in mangrove forests that were close to both large seagrass meadows and coral reefs, and with abundant pneumatophores and low mangrove tree canopy cover. We therefore found positive effects of reserves on animal assemblages, but not on ecological functions, and show that ecosystem multifunctionality is not always tightly linked with biodiversity. The results of this study highlight the importance of quantitative conservation goals, and in integrating data on both the ecological condition and spatial context of ecosystems when prioritizing conservation to maximise both biodiversity and ecosystem multifunctionality.