From Populations to Ecosystems: Theoretical Foundations for a New Ecological Synthesis

A defining feature of ecology over the last few decades has been a growing appreciation of the importance of considering processes operating at spatial scales larger than that of a single locality, from the scale of the landscape to that of the region (Ricklefs and Schluter 1993; Turner et al. 2001). Spatial ecology, however, has reproduced the traditional divide within ecology between the perspectives of population and community ecology on the one hand and ecosystem ecology on the other hand.

The population and community ecological perspective has focused on population persistence and species coexistence in spatially distributed systems (Hanski and Gilpin 1997; Tilman and Kareiva 1997) and has a strong background in theoretical ecology and simple, generic mathematical models. The metapopulation concept has occupied a prominent role in the development of this perspective (Hanski and Gilpin 1997). A metapopulation is a regional set of local populations that are spatially distinct but connected by dispersal, such that each population undergoes a dynamics of local extinction and colonization from elsewhere. The strength of this concept has been its ability to deliver specific testable hypotheses on the increasingly critical issue of conservation of fragmented populations in humandominated landscapes. Because local extinction and colonization can be influenced by interspecific interactions such as predation and competition, a natural extension of the metapopulation concept is provided by the metacommunity concept, which designates a set of communities that are spatially distinct but connected by dispersal (Leibold et al. 2004). Significant new insights are being gained from the metacommunity perspective (Holyoak et al. 2005).

Another perspective, however, has developed from ecosystem ecology and is represented by landscape ecology. Landscape ecology is concerned

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