Biodiversity is regarded as a scientific concept, a measurable entity, as well as a social–political construct (Gaston 1996, Wilson 1993). The aim of this volume is to develop the scientific basis for biodiversity studies, and for the integration of the concept into management practice. We emphasize biodiversity as a powerful, integrative concept—one that requires careful articulation and further conceptualization before application. Diversity is a concept that refers to the range of variation or differences among a set of entities; biological diversity then refers to variety within the living world. An example of biological diversity is “species diversity,” which is commonly used to describe the number, variety, and variability of the assemblage of living organisms in a defined area or space. However, biodiversity as a concept has evolved. Current definitions expand the biological diversity concept to emphasize the multiple dimensions and ecological realms in which biodiversity can be observed. These definitions stress that biodiversity encompasses at least four kinds of diversities: genetic diversity, species or taxonomic diversity, ecosystem diversity, and landscape diversity (McAllister 1991; Solbrig 1993, Stuart and Adams 1991; Groombridge 1992; Heywood 1994, Wilson 1993). Two main problems emerge as a consequence of the broad scope that the biodiversity concept has taken at present. Cast as questions, the problems are: (1) How do we incorporate processes (e.g., foraging, energy and nutrient flows, patch dynamics) into a concept that is based on seemingly static entities (i.e., individual organisms, species, habitat types, patch types)? (2) How do we integrate across ecological subdisciplines (e.g., ecosystem, population, landscape ecology) and across scales that are involved in biodiversity studies? The two problems are not mutually exclusive. Indeed, they are inseparable and complementary. For example, to determine how species diversity and ecosystem processes interact requires incorporation of entities and processes, as well as integration of community and ecosystem ecology. The focus on both entities and processes reflects the long-recognized dichotomy of structure and function in biology and ecology. Clearly, both structure and function must be integrated in order to successfully solve ecological questions. Dealing with biodiversity brings this needed integration into focus.
Crab scars reveal survival advantage of left-handed snails