Study On The Dynamic Changes Of Small Lakes Of Bosten Lake And Its Drivers The Past40Years

The lake is a sensitive area of global environmental change,is a typical area ofglobal environmental change research, especially inland lakes. Lakes is an indicator ofclimate change and environmental variability. Inland lakes in arid area as a uniqueecosystem unit in arid region, is one of the basic spaces to maintain the arid area ofhuman survival and development. In recent years, with the rapid development ofregional socio-economic, under the influence of human large-scale land and waterdevelopment activities, the inland lake ecological environment has been a continuousdisturbance of human activities, affected the ecological environment of the lake,Therefore, climate change and human activities under a coupling of ecologicalrestoration and its adaptation to changing hydrological conditions is a key of lakeprotection and management.The small lake in Bosten Lake as a study area in this thesis,1976,1990,2002and2009remote sensing data were processed by applying3S technology to find out thearea variation law and its driving factors of small lakes in Bosten Lake for nearly40years. The results are as follow:（1）The water area is in a greater Change by human activities influence from1976to2009in the study area. The Bosten Lake Basin is a continuous dry years from1982to1990, Bosten Lake water level is in a continuous minimum water level at thisperiod, small lake water area reduced more than752.54hm~2in1990to1976. BostenLake Basin devastating floods in2002, Bosten Lake water level fluctuations rise,Bosten Lake in the highest water level in history, accordingly small lake wetlands is inhigh water level, Small lake water area has expaned than in1990. After2002, thewater level began to decline, generally shows a trend of shrinking.Based on the results, the rate of landscape pattern is faster than in1990after12years small lake in Bosten Lake, Indicating that the impact of human activities and ecological environment change is more obvious after the1990s. Accordance to thetransfer matrix, from1990to2002in the study area landscape changes faster thanfrom1976to1990, the rate of change reaches-1.421, indicating that the lake has beenseverely damaged, Deteriorating ecological environment. The lakes dynamic degree islarger than2.87%in2002～2009to1990～2002, the degree of influence of humanactivities on the lake is more and more increased.（2） Wetland landscape is in a significant change in each study period. Sumedup, landscape diversity index and evenness index increased first and then decreasedtrend in study period, turning point in2002, showed landscape heterogeneity smallerof the year2002in the study area, the impact of human activities is smaller, hasincreased after2002, the landscape types is in the trend of diversifying direction ofdevelopment, regional landscape pattern become increasingly popular with themajority of plaque control, the landscape diversity is increased,the degree oflandscape heterogeneity and complexity increased. Landscape dominance indexshowed a trend of increasing at first and then decreasing, increases0.06in1976to0.16in1990, begins to increase after2002, showed farmland is becoming more andmore dominant in the area, the separation between the different plaque decreases andthen increases, showed landscape fragmentation degree is deepen, this related humanactivities on land use change impact strength.（3）Small lake surface area change closely related with meteorological factors,meteorological elements influence water level through rivers, temperature and lakesurface area change was negatively correlated, the correlation coefficient is-0.84,precipitation has little to do with the small lake, the decrease in temperature andprecipitation increase is the main reason for the widening of small lakes area inBosten Lake.As can be seen from the land use transition matrix, lakes transformed into arableland area is0ha from1976to1990in study area, human beings had no significant effect on the lake at that period. Lakes transformed into arable land area is189.25hafrom1990to2002in study area, showed that the role of human activities on the lakeis began to strengthen.