Landscape Pattern Changes In Chongqing

There are58nature reserves in Chongqing. On a macro level,a systematic study of nature reserves is still blank. Therefore, it’s of little possibility and necessity to conduct a landscape pattern study on nature reserves distributing in Chongqing. This paper selects six municipal representative nature reserves as the main object of study (six nature reserves relates to natural ecosystem nature reserves, wildlife nature reserves and nature relics reserves). Meanwhile, it combines with the actual situation of Chongqing’s six nature reserves. With the support of "3S" technique, it makes use of TM image of2000,2005,2010, and conducts a pattern analysis on the landscape type of six nature reserves through ArcGIS and Fragstats3.3software. The selected landscape pattern indices include plaque number, patch density, patch area, proportion of plaque area, dynamic degree of plaque area, landscape shape index, fractal dimension of plaque, fragmentation index,Shannon diversity index, and Shannon evenness index. On the basic quantitative analysis of landscape pattern change in the six nature reserves, this paper evaluates driving factors changing their landscape pattern. Thus, it analyzes nature reserves, the experimental zone, the buffer zone, and the core area, comprehensively evaluating the protective effect of the prohibiting measures in Chongqing’s nature reserves. What’s more, it provides a theoretical basis for the management and decision-maKing of the relevant departments.The results indicates that:(1) Changes of the number of landscape typeIn these six nature reserves, the landscape type number of Simian Mountain, Baima Mountain, Wangerbao Mountain, Pengxi River, Huaying Mountain and Xiaonanhai is respectively13,10,13,15,13and17. Among them, Pengxi River and Huaying Mountain still have industrial patch types. In2010, bare soil plaque of Pengxi River has disappeared. In all, their patch number are changing, for example, patch number of Simian Mountain and Huaying Mountain reduces;while, patch number of the rest does increase. (2) Changes in plaque areaIn these six nature reserves, changes of plaque area varies considerably, dry and land area reduces at most. Dry and land area of Simian Mountain, Baima Mountain, Wangerbao Mountain, Pengxi River, Huaying Mountain and Xiaonanhai is successively90.09hm2、54.81hm2、50.76hm2、301.05hm2、25.17hm2、648.27hm2. In the meantime, increase in plaque area mainly is the increased woodland or grass, in which Pengxi River’s dry land becomes paddy fields or rivers.(3)Changes in patch shape indexIn six nature reserves, Xiaonanhai’s patch shape index is maximum. On the contrary, Pengxi River’is minimum. In a period of10years, Huaying Mountain, Wangerbao and Baima Mountains’ patch shape index increased, but the rest’s in turn reduced.(4)Changes in plaque densityIn six nature reserves patch density from big to small is as followed:Pengxi River, Xiaonanhai, Huaying Mountain, Wangerbao, Baima Mountain and Simian Mountain. And their plaque density reflects the fragmentation degree, among which, the highest fragmentation index is Pengxi River, the lowest one is Simian Mountain; Simian Mountain and Pengxi Rivers’ fragmentation index is lessened, the other four show a trend to rise.(5) Landscape diversityIn six nature reserves, the diversity index descending order is Huaying Mountain, Pengxi River, Wangerbao, Baima Mountain, Xiaonanhai and Simian Mountain. Therein, diversity index increased in Pengxi River, Huaying Mountain, Wangerbao, Xiaonanhai and Baima Mountain; diversity index decreased only in Simian Mountain.(6)Landscape evenness indexAll of these evenness index descends as follows (take reserves’ evenness index in2010as the principle thing):Huaying Mountain, Baima Mountain, Wangerbao, Pengxi River, Xiaonanhai and Simian Mountain. The evenness indexes of Pengxi River, Wangerbao and Baima Mountain increased. Therein, Pengxi River’s evenness index mainly increased in the period2005-2010, Baima Mountains’ evenness index increased in2000-2005, but decreased in2005-2010,and decrement was not very large. During the period of2000to2010, evenness indexes of Huaying Mountain, Xiaonanhai, and Simian Mountain reduced.(7) Landscape pattern driving forceChanges in landscape pattern of nature reserves partly attributes to the natura factors, but the dominant factor is human’s interference and policy wizard.