Remote Sensing-Based Land Use/Land Cover Change And Its Effects On Ecological Environments

The land use and land cover change(LUCC)is one of the core researches of International Geosphere-Biosphere Program(IGBP)and International Humanistic Dimensions Programmed(IHDF)on global environment change,and has been the global environment research hotspot.For either ecology or economy development,it plays same important role..China,as one of the civilized countries in this world, its land use and land cover experienced huge change after long human utilization especially recent years the increasing natural resource demands with rapid economy development.This huge change has caused sharp conflict between economy development and ecology environment protection and hence need more effective researches on regional land use and land cover and its effects on environments.At present,most of the study of land use and land cover change and its influence on environment just focus on ecological fragile or economic developed areas.,and lacks researches in complex topography areas like hilly mountains in southwest china,which rather is quietly important indeed.Meanwhile research of quantitative evaluation on regional environment quality is still in the initial stage,andtakeing the ecological and environment into account when analyzing the sustainable utilization of land use still need more concerns.Consequently the research of environment effect about land use and land cover change in complex topography becomes the main content of current land use and land cover change(LUCC).In this dissertation,the author select the "Chongqing one hour economic circle" where is the combination of urban and rural in Chongqing along with economy highly developed and human activity frequently as study area.Base on the TM/ETM images of 1988,2000 and 2006,the author analyzed the land use and land cover change(LUCC),the driving factors of LUCC and the changing of climate as well as the urban heat island.In the end,environment quality of research area was given detailed evaluation in quantitative way.This study will be able to supply good foundation on solution of conflicting among regionall sustainable land use,ecological environment and sustainable increase of economy.The conclusions can be draw as follows:1.The classification of land use and land cover change base on TM/ETM image In this dissertation,author established a special classification system about LUCC that combined the special Terrain of Chongqing and the second land survey of china,although the latter hasnt formally started yet.The system includes seven types:paddy field,dry land,woodland,grassplot,residential points and industrial and mining land.The author interpreted the TM/TEM image of 1988,2000 and 2006 with Computer automatic classification and artificial visual interpretation and concluded that the total accuracy of remote sensing image of 2006 arrived 88.53%,classification precision of woodland and housing centre is 90%that is upper than paddy field and unutilized land which are 89.31%,87.5%respectively,and the lowest are grassland and water area with only 83.96%and 83.18%respectively.But all of them can satisfy the demands of classification precision.meanwhile,the author found the variation of land use of residential points,unutilized land and industrial and mining land are the most;the water surface declined little;the area of forest land grassland enhanced;however the cultivated area(paddy field and dry land)shrank.2.LUCC analysis based on the index of landscape-ecology and land-use/land cove change By building a series of land-use index models,such as landscape spatial pattern index and land-use change matrix,the author analyzed changes of land-use structure and transformation with different land-use types.The conclusions can be draw as follows::(1)Under the activity of human being,fast changes had taken place in landscape pattern,thus landscape heterogeneity increased.Area of cropland decreased fast,while that of residential area and land of industries and mining increased quickly.Area of woodland and grassland increased a little,however,that of unused land decreased sharply.Thus,transformation between different land-use types was frequent, especially the transformation between paddy field and dry land,which was different from plain area. During the three study periods of the study area,the proportion of the largest piece(LPI)decreased gradually,while piece density(PD)and edge density(ED)increased consistently,thus,the total fractal index and landscape fragmentation increased,impacts of human on landscape was increasing.Compared with the piece type level index and landscape level index,paddy field and dry land indicated a approximate change state with the landscape level index,in other words,fractal index increased continuously and the degree of landscape fragmentation also enhanced during the study period,so the geometric shape of the piece become complex.The shape of residential area and land of industries and mining become irregular due to the impacts of topography and traffic,average piece area increased quickly and shape of piece become complex,deviation of piece decreased gradually,the largest piece index presented a increasing state,but landscape fractal index increased a little.Changes of landscape pattern would induce several ecological effects.As a whole,depression of the regional nature ecological value would pose a negative impact on food supplies,water quality,soil and biology diversity.(2)The author found that cropland decreased dramatically over the past 20 years by investigating the cropland area and spatial change of land-use types.The distribution of conversion from paddy field to residential area and land of industries and mining,which presented remarkable regional difference,mainly distributed in the area of fast urbanization including Jiulongpo,Shapingba,Jiangbei and Yubei which was forming layer of the city;the pattern of transformation of dry land mainly included dry land—woodland and dry land—paddy field,while the transformation from dry land to residential area and land of industries and mining presented remarkable regional difference,which was mainly distributed in Changshou,part of Yubei,Tongliang and Hechuan,these area were the middle layer of the city;and that Wansheng,Nanchuan, Dazu and Tongnan were the exterior layer of the city,transformation between paddy field and dry land was the main pattern in these area.In sum,reduction of cropland resources was smaller during 1988 to 2000 compared with that during 2000 to 2006.(3)The related index of land use/land cover change presented remarkable temporal-spatial difference. The author investigated land-use dynamic index and found that residential area and land of industries and mining increased most fastly during the whole study period,and then were grassland,woodland,dry land, paddy field,water area and unused land in turn.Integrated land-use dynamic index was the most during the period from 2000 to 2006 which indicated that the intensity of land-use change was much stronger during the later period than that during the former period.The intensity of land-use change show clearly spatial difference.The intensity of land-use change were the most strongest in Tongnan,Dazu,Hechuan and Tongliang,while next were Beibei,Yubei and Changshou in turn.In the main city zone,land-use intensity of Jiangbei and Nanan were in the developing period,while that of other area were falling into a decline period.The intensity of land-use change during the later period obviously differed from that during the period 1988-2000,land-use intensity of Shapingba,Nanan,Yuzhong,Jiangbei and Yubei,which was suited in the main city zone,were falling into a decline period,while that of Yongchuan,Jiangjin,Fuling and Nanchuan were in the developing period.3.Driving forces analysis on LUCC(land use and cover change) LUCC is driven by natural factors and society economy factors,The study area is a typical hilly landscape,The main driving factors are natural landscape,altitude and elevation which effect on each type of land use changes significantly,because the land use of the area above 800 meters are mainly woodland, so it is especially important for us to research on distribution law of the land types of the area below 800 meters.In 1998,the largest proportion in the area below 400 meters was watershed,followed by the mining sites and settlements,dry land,paddy field,unutilized land,woodland and pasture.The area percentage below 400 meters was 89.44%in watershed,while 85.49%in mining sites and settlements,however the largest relative area percentage between 400 meters and 800 meters arrived 46.52%in pasture.The most of cultivated land distributed in the area below 400 meters,the proportion in paddy field and dry land were respectively 61.9%and 62.6%.In 2000,the area below 400 meters was also watershed,mining sites and settlements,the proportion of both unutilized land below 400 meters and woodland between 400 meters and 800 meters raised a little,it showed that most woodland transform into the other types of land use in low altitude area,however,most unutilized land and the other types of land use transform into woodland in low and mediad altitude area,and the changes in woodland had metastatic trends in low and middle altitude area in the years from 1988 to 2000.The area proportion between 400 meters and 800 meters raised a lot in mining sites and settlements,the total distributed area on woodland had a trend of rising,while the distribution in pasture had a trend of decreasing. The results showed that there was a three-dimensional development in all city construction,the urban greening project improved a little,the project of returning land for farming to forestry had a lot of significantly effects on research area.The variation characteristics on farmland were driven by social economic factors,the mainly factor which effects the changes of farmland area was economic factors.The quantity of farmland showed decreased in the linear relationship with the total output value,the total fixed assets investment in whole society and the gross industrial production value,the fixed investment and the gross domestic product(GDP)increasing have a certain lag effect compared with the occupied of the farmland.4.The research on climate and urban heat island change characteristics based on classic statistical methodsSliding t-test is used in this dissertation,while analyzing annual variation and seasonal change on urban heat island on the study area in 1980-2006.The results can be concluded as follows:(1)The temperature change characteristics on the study area were similar to the climate change characteristics under the background of global change,since 1980s,all of them showed the tendency of rising,they mainly appeared as negative anomaly before 1997,and positive anomaly after 1997,the temperature increased by 0 56℃after the jump compared with that before the jump,so it is in fact that the temperature add 0.33℃in every 10 years.The same method was used to analysis data from each weather station,the result showed that the temperature increased after the jump compared with that before the jump, the temperature in all main city increased a lot,especially in Tongliang weather station,it was at 0.96℃,more increased than anyone,the least one was Dazu at 0.38℃,Spring was the most obviously one in seasonal temperature changes,the jump year was 1997,the temperature difference before and after the year was 0.89℃,equal to 0.53℃in every 10 years.The summer temperature showed an periodical change, and the jump temperature was not significant;The jump year in autumn was 1995,the temperature difference before and after the year was 0.72℃,equal to 0.47℃in every 10 years,the jump year in winter was 1996,the temperature difference before and after the year was 0.59℃,equal to 0.37℃in every 10 years.(2)In recent 30 years,it was obviously that the high temperature centers appear in urban of Beibei, Shapingba and so on,and they gradually decreased in suburbs of Dazu,Rongchang and so on,the average local temperature in the study urban areas were 0.54℃from 1980 to 2006,and in the study suburb areas were -0.22℃,the average Urban Heat Island Effect was 0.76℃.The local temperature increased obviously in the study urban area,and decreased a little in suburbs,the Urban Heat Island Effect almost had been increasing obviously,in recent 30 years,the changes of the Urban Heat Island Effect showed a regular distribution.5.Ecological environment quality quantitative evaluation and variation characteristics analysis In this dissertation,the author established the regional ecological quality comprehensive evaluation model by using the analytic hierarchy process.Average temperature,heat island intensity,rainfall, biological abundance index,the density of water as well as NDVI were chosen as indicators to quantitatively evaluate regional quality of the ecological environment and the conclusions can be depicted as follows(1)As a whole,some districts in the West Chongqing region such as Tongnan,Tongliang,Dazu, Bishan,Yongchuan and Rongchang which has a lower level of ecological environment,but the district of Changshou has a high level.After standardization on evaluation results,it shows that within two years, areas that were ranked as excellent and good accounted for 62.56%and 60.96%respectively,but excellent areas decreased by 3%and in 2000,the area that were ranked as average accounted for 39%whereas in 2006 the percentage was decreased to only 12.36%.It was obvious to see that in the southwest area of Chongqing,the ecology quality was tending to decreasing trend.(2)Form 2000 to 2006,the overall quality of the ecological environment of the area was clearly declining,significant deterioration area ratio reached 31.7%,and significantly change good regional area ratio was only 5.2%.And the dropped ecological environment of research regional area ratio reached 59.7%and the increased ecological environment of the region area was only 27.1%.Regional changes in the quality of the ecological environment had obvious spatial difference.Most significant deterioration of regional distributed in the southwest of Chongqing where belongs to regional of Cheng-Yu Traffic Route and the large parts of the capital city.Land-use/cover change(LUCC)plays a very important role in Global Change Research,its ultimate aim is to find a harmonious and sustainable development direction from the human process and natural process.In this dissertation,the author used the remote sensing images to obtain characteristics of regional land use/land cover changes,and utilized meteorological data to analyze regional climate Decadal Oscillation and the heat island effect.These acquired results were made as parameters of regional environment quantitative evaluation and the final evaluation result will be able to provide good foundation for local land use planning,the sustainable development of ecological environment and land resources.