Habitat is the fundamental unit for understanding species ecology and preserving biodiversity; it has always had a variety of meanings often not explicitly defined. This important book focuses on the two main uses of the term and their importance for nature conservation. The first, traditional usage (TH), is that of terrestrial, aquatic or aerial spatial units which can be denoted by the species they host, with associated trophic relationships and interdependencies. The second, termed resource-based habitat (RBH), focuses on any one species' habitat. These RBHs are rarely limited to one space but are defined by the intersection of appropriate resources and suitable conditions. Since the ability of individuals to exploit resources is influenced by their own unique combination of traits, the RBH is spatially and temporally variable. The book explores how communities are structured, how species and individuals interact (niches, guilds, food webs, etc.), and how biodiversity changes over