干旱区绿洲景观尺度稳定性初步分析

Preliminary Analysis on the Oasis Stability at the Landscape Level in the Arid Regions

在景观尺度上,从绿洲景观多样性、景观廊道的复杂性以及土地利用及其生态环境效应等方面探讨了绿洲景观稳定性的内涵,并对新疆三工河流域绿洲进行实例分析和应用。结果表明(1)人工绿洲景观的稳定需要绿洲景观的多样性逐渐降低和景观廊道的复杂性增加;但天然绿洲的稳定需要增加景观的多样性和景观廊道的复杂性。(2)人工绿洲景观稳定性还可从绿洲土地利用变化方面分析,绿洲土地利用变化是人类投入大量负熵的结果,投入的负熵越多,绿洲土地利用程度越高,越有利于绿洲从低级的亚稳定状态不断向高级稳定态发展,从而实现绿洲可持续发展。但人类的投入并不总是有利于绿洲的稳定,可用土地废弃比例的变化,说明人类投入对绿洲生态环境和稳定性造成的影响,土地废弃的比例越高,绿洲生态环境的质量也就越低,绿洲的稳定性也就越低。(3)通过绿洲景观多样性、景观廊道的复杂性和土地利用状况综合评判,1978～1998期间三工河流域绿洲景观及其各部分的稳定性逐步提高。

Taking the oasis in the Sangong River Watershed(Fukang County, Xinjiang) as the study area, mainly using remote sensing image data in the similar periods of 1978, 1987 and 1998, the landscape stability of the oasis is researched from many aspects including landscape diversity, corridor complexity and land use change. The main results of stability of the oasis landscapes are as follows:(1) The stability of the artificial oasis landscapes needs that the oasis landscape diversity is gradually decreased and the complexity of landscape corridor is increased. However, the natural oases show the different situation: the higher their landscape diversity and the more complex their landscape corridor are, the higher their stability will be.(2) It is necessary to analyze the stability of the artificial oasis landscapes from land use change. Land use change in oases is the result that human inputs the much negative entropy. The more human inputs, the higher the land used extent will be and the more advantageous the conditions for the oasis evolution from the low level and the sub stability to the high level and the stability, thus the sustainable development of an oasis can be achieved. However, the input in an artificial oasis is not always advantageous for the oasis stability. The proportion of the abandoned lands can be used to reveal the impacts of human input on the ecological environment and oasis stability: the higher the proportion of the abandoned lands is, the lower the quality of the ecological environment in the artificial oasis and its stability will be.(3) The analysis on the landscape diversity, corridor complexity and land use change in the Sangong River watershed reveals that the stability of the oasis has been gradually increased since 1978.