土地利用结构与生态过程

LAND USE STRUCTURE AND ECOLOGICAL PROCESSES

本文从土地利用与土壤水分、土地利用与土壤养分、土地利用与水土流失 3个方面系统讨论了土地利用结构与生态过程研究的现状和特征 ,指出 :1 )土地利用结构对土壤水分的影响涉及生态系统、坡面、小流域和区域等系列尺度 ,土地利用的分布及景观特点影响土壤水分的时空变异 ;2 )土地利用对土壤养分的影响表现在土地利用的镶嵌格局影响土壤养分的分布和迁移 ,土地利用的变化可以引起土壤养分的变化 ;3)土地利用与水土流失关系密切 ,土地利用的改变能够减少或增加径流和土壤侵蚀。尺度不同 ,土地利用与水土流失的机制也不尽相同。土地利用结构与生态过程的研究 ,还需要注重大尺度和多尺度上的综合研究。

As one of the key topics of landscape ecology, the relationship between landscape pattern and ecological processes has been paid much attention recently, in particular on the relationship of land use structure and ecological processes, such as soil moisture dynamics, soil nutrient change and soil erosion. In this paper, the key issues of land use structure and ecological processes are discussed. (1) Soil moisture plays an important role in plant growth and vegetation rehabilitation, and has a high temp-spatial heterogeneity. The study on tempo-spatial variation of soil moisture involves multiple scales from ecosystem, transect, catchments (or watershed), to large basin. The characteristics of spatial distribution of soil moisture are largely dependent on land use types, topographic position, soil texture and others. (2) The spatial pattern and transportation of soil nutrient are affected by the heterogeneous landscape, which is closely related to the land use structure. Usually, different land use types may result in different patterns on nutrient loss and runoff. The combination of land use types on the hill-slope may bring a complex consequence on soil nutrient. (3) It has been found that the main reason of soil loss is inappropriate land use. The obvious effects of land use on water and soil erosion may be properly forecasted by using soil erosion model. However, how the factors affect the water and soil loss is still not clear at present, and the mechanism of soil erosion is different with scale changing. Studys on the relationship between land use structure and ecological processes are imperative and significant tasks understanding for land use change and related environmental effects. However, most current researches are conducted at the small scale. It is necessary to pay much more attention on the large scale or multiple scales.