生态学范式变迁综论

PARADIGM SHIFT IN ECOLOGY: AN OVERVIEW

拟总结生态学研究在若干方面的最新进展，并涉及到平衡与非平衡、同质性与异质性、决定性与随机性，以及单一尺度与等级关联等问题。在此基础上，作者将对生态学中的范式变迁作一论述。缀块动态观点和等级理论的结合，使尺度与空间异质性明确地联系在一起，从而正在形成一个新的生态学范式，并导致了关于生态学系统时空动态的新观点．等级缀块动态范式的主要内容包括缀块等级系统概念、系统动态与缀块变化观点、格局－过程－尺度观点、非平衡观点和兼容与复合稳定性原理．环境的随机性和生物反馈作用均可引起生态学系统不稳定性．减缓这些不稳定因素的一个极为重要的机制即空间和时间尺度上的兼容和复合稳定性过程．等级缀块动态范式的最重要贡献之一就在于它为生态学提供了一个新理论构架，使异质性、尺度和等级特征相结合，并使平衡态，多平衡态及非平衡态等观点相统一。

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.