Toward a Unified Framework in Biodiversity Studies

Biodiversity has been defined as the “full variety of life on Earth” (Takacs 1996). Because biodiversity refers to a fundamental property of ecological systems, it continues to develop as a scientific frontier for exploration and discovery. Ecological systems are a mixture, or diversity, of living and nonliving entities interconnected by a web of interactions. Biodiversity is a concept used to describe the number, variety, and organization of entities in the biosphere, or a unit of the biosphere, and their relationships to each other (Gaston 1996). More importantly, biodiversity includes consideration of processes that create and maintain variation in ecological systems (Groombridge 1992). Therefore, biodiversity is not simply about entities and taxonomy. Rather, biodiversity is concerned with the diversity of species within communities, the range of ecological processes within ecosystems, and the diversity of ecosystem processes across landscape mosaics (Heywood 1994, Levin 1997). A similar perspective on biodiversity is provided by Noss (1990), who applies the concept over hierarchical levels of organization ranging from the gene to the entire biosphere, and recognizes compositional, structural, and functional approaches to biodiversity. In contrast to this broad and comprehensive scope of biodiversity suggested above, researchers and conservationists often employ a narrow definition of biodiversity shaped by their values, interests, and goals. A more precise and more widely recognized interpretation of the scope of biodiversity is required in order to promote scientific research and to develop management programs (Christensen et al. 1996). The objective of this chapter is to build on the comprehensive framework for biodiversity proposed in the introduction (chapter 1, fig.1.1) and combine it with additional insights from the other chapters. The initial framework recognizes biodiversity to include four components, and one complex output. The components are the roster of entities, the number of each kind of entity, the nature and degree of difference between the entities, and the spatial or functional organization of the entities. The outcome is the effect of biodiversity on ecosystem processes. This framework enables us to (1) map, in a more unified way, the present achievements of research in the field of biodiversity, (2) understand the complexity of biodiversity, and (3) advance the scientific basis for biodiversity management.