A hierarchical ecological approach to conserving marine biodiversity

A number of ecological models have been developed to provide an understanding of the various biotic and abiotic components required to conserve biodiversity and to reconcile objectives and methods between those interested in the conservation of species (e.g., population management) and those advocating the conservation of spaces (e.g, protected areas). One of the better known efforts-pioneered in the Pacific Northwest of the United States-is a hierarchical ecological framework, that separates biodiversity into compositional, structural, and functional attributes at the genetic, population, community-ecosystem, and landscape levels of organization. We present an adaptation of this terrestrial framework consistent with the ecological function of marine environments. Our adaptation differs in its treatment of the community and ecosystem levels of organization. In our marine framework, the community level denotes predominantly the biotic community components of biodiversity, and the ecosystem level-consistent with marine terminology-denotes predominantly physical and chemical components. The community and ecosystem levels are further separated into those attributes based on ecological structures such as depth or species richness and those based on ecological processes such as water motion or succession. The distinction between the biotic (genetic, population, and community) and abiotic (ecosystem) is required because the biological components of biodiversity such as competition or predation are often more difficult to observe than the abiotic components such as upwellings, substratum, or temperature. As a result, efforts to conserve marine biodiversity are often dependent on the observable abiotic (ecosystem) components, which can be used as surrogates for the identification and monitoring of biotic (community) components. We used our hierarchical framework to identify, and suggest how conservation strategies could be implemented in marine environments depending on whether existing data are to be used or new data are to be collected.