PARADIGM SHIFT IN ECOLOGY: AN OVERVIEW
生态学范式变迁综论

Paradigm refers to the world view and a system of concepts, theories and methods shared and used by a scientific community. Scientific advances are usually accompanied by shift in paradigms. A common assumption historically in ecology is evident in the term "balance of nature". The phrase usually implies that undisturbed nature is ordered and harmonious, and that ecological systems return to a previous equilibrium after disturbances. The more recet concepts of point equilibrium and static stability, which characterize the classical equilibrium paradigm in ecology, are traceable to the assumptions implicit in "balance of nature". However, the classical equilibrium view failed not only because equilibrium conditions are rare in nature, but also because of our past inability to incorporate heterogeneity and scale multiplicity in our quantitative expressions for stability. The theories and models built around these equilibrium and stability principles have misrepresented the foundations of resource management, nature conservation, and environmental protection.This paper synthesize recent developments that advance our understanding of equilibrium vs. non-equilibrium, homogeneity vs. heterogeneity, determinism vs. stochasticity, and single-scale phenomenon vs. hierarchical linkages in ecological systems. The integration of patch dynamics with hierarchy theory has led to new perspetives in spatial and temporal dynamics with explicit linkage between scale and heterogeneity. The major elements of the hierarchical patch dynamics paradigm include the idea of nested hierarchies of patch mosaics, ecosystem dynamics as a composite of patch changes in time and space, the pattern-process-cafe perspective, the non-equilibrium perspective, and the concepts of incroporation and metastability.Both environmental stochasticities and biotic feedback interactions can cause instability and contribute to the dynamics observed at various scales. Stabilizing mechanisms that dampen these destabilising forces often involve spatial and temporal incorporation.In contrast to the stability that derives from an assumed self-fregulation in a closed system, the concepts of incorporation and metastability deal explicitly with multiple-scale processes and the consequences of heterogeneity. The most important contribution of hierarchical patch dynamics lies in the framework provided for incorporating heterogeneity and scale explicitly, and for integrating equilibrium, multiple equilibrium, and non-equilibrium perspectives.