Land Use Change And Its Ecological Environmental Effects Around The Dongting Lake

Basis on the reviews and summarizes of land use change research and its environmental effects, with a typical lake-Dongting Lake as the subject, the land use in space and time in recent 15 years was established, The data used is 1996,2001,2007 and 2011 remote sensing information database, the study explores the typical lake land use temporal and spatial evolution, and its single factor and multi-factor coupling relationship with environmental factors, anaryze the specific response mechanism. On the basis of these results, the study, optimizes the CLUE-S model, simulates and predicts the trend of future land use and environmental change, finally provide in-depth reference to the decision-making on the lake land sustainable utilization and environmental protection. This study’s main contents and conclusions inc lude:The main contents of study:1. With landscape ecology and GIS analysis method and land use dynamic model, land use dynamic change characteristics and landscape pattern and its driving factors were analysised.2.The background of environmental quality in 2001 and 2007 was reconstructed, with multi-source remote sensing data.at the same time, the lake ecological environmental quality changes in future 14 years was predicted used the grey multiple regression models.3. Base on the classification of land use in 2001 and 2011, the grade of land use intensity was formulated, which applied to the Information express of land use intensity, then the lake surface temperature was inversd by two-factor model.4. The multi-factor coupling relationship of LUCC and ecological environment in 1996-2011was explored with an canonical correlation analysis method, the canonical correlation between land use and social-economic factors, landscape ecology and land use change was analysised. The relationship between them can be represented by the corresponding typical variables.5. Based on CULE-S and grey prediction model, the future land use space change in year 2016,2021 was simulated, the proposals for decision-support was made by the simulated results.The main conclusions of study:1. The lake district land use structure changed significantly, the rapid increase of construction land growth reached 78.7%, mainly through encroaching on cultivated land and forest land; the increase in cultivated land is small by 6.2%, mainly encroaching on woodland and grassland; Woodland initially decreased, but then increased, but totally reduced by nearly 20%;water and grass land decreased by 11.5% and 11.5% respectively; degree of land use change was given priority to construction land, forest land, water; land use degree change is high in the east but low in the west; in landscape pattern of land use, the overall fragmentation increased, the fractal dimension reduced, and the diversity degree of spread slightly reduced.2. Lake ecological environmental quality overall declined in the seven years, rainfall reduced, vegetation coverage was reduced, the surface temperature increased. The intensity of land use is the main factor that led to the decrease of the environmental quality. The study predicts lake area land ecological environmental quality in the short term future with degrading trend, by 2021 environmental quality degradation in 2007 will be 18.5%. As a result of the accumulating effect of environmental factors of the lake environmental quality change, the main impact of different environmental factors (rainfall, temperature, light, etc.) in a certain space area gathered, will lead to the change of environmental quality.3. The rule of land use intensity in response to temperature change was revealed,converting unused land, woodland and grassland into farmland and construction land will cause the decrease of the underlying surface reflectance of land utilization, leading to the temperature rise; when the level of land use intensity in transition, the temperature will rise obviously, and the intensity of land use of small increases has insignificant impact on temperature rise; the responding process of the land use intensity change to the temperature change is in synchronization with the temperature change itself, both show the trend of decrease with the increase of latitude. Temperature rate is higher at the lower latitude than at the higher latitude, the temperature effect on the land use intensity is more sensitive, more vulnerable than the effect of land use.4. The canonical correlation analysis on land use with social and economic elements shows that land use change can be used with the corresponding typical variable to measure; Construction land, cultivated land, forest land and population not only have typical correlation with GDP and urbanization, but also with NP, PD, LSI, ED; water body is not only canonically correlating with agricultural population and urbanization,, but also is strongly sensitive to the NP, SHDI, CONTAG,temperature and sunlight; The grassland is only sensitive to the agricultural population, urbanization, SHDI, IJI, temperature and sunlight.5 Water, wetland, urban construction, forested land protection partition was proposed, with a mosaic partition protection approach, water resources protection was used a buffer zones, which was emphasized the importance of grading and adjust measures to local conditions, these ways can be provided references for lake environmental protection.