Spatial pattern of ecosystem function and ecosystem conservation.

The spatial pattern of ecosystem function can affect ecosystem conservation. Ecosystem functions are often heterogeneous spatially due to physical and biological factors. We can influence ecosystem functions by changing the spatial patterns of the physical and biological elements of an ecosystem and regulating their combinations. The variation-position effect highlights a phenomenon resulting from the spatial pattern of ecosystem function. The effect shows that the identical variation of a factor may produce different effects on the over-all situation when this variation occurs in a different spatial position. In a watershed of the Yangtze River, water retention is a primary ecosystem function. The variation-position effect for water retention capacity occurs in the watershed because of the spatial heterogeneity in vegetation, soil, and slope. The change of vegetation that occurs in a complex can affect the overall situation of water retention, and the effect can be different due to the change occurring in the position holding different vegetation-soil-slope complex. To improve the ecosystem in the watershed and to meet the social needs for the ecosystem function of water retention, a strategy called "ecosystem function and spatial pattern-based forest extension" was proposed to conserve forests. The implementation of the strategy enables the watershed to attain the maximum effective increase in water retention capacity.