| Take the middle reaches of Hei River Basin as the study area, combinated with RS, GIS technology, dynamic model of the land exploitation, ecological service value evaluation method, to carry out land use / land cover change and its environmental thermal effect research from the basin scale and county regional scale. Based on sustainable development in Hei River area. Through the establishment of decision tree classification model to classify the TM / ETM Remote sensing image, 2000- 2010 years, the area of land using dynamic change analysis, analysis of the typical county land use landscape characteristic analysis, study area in 2000 and 2010 thermal environment effect analysis, ecological service value analysis that the following conclusions:(1)In the middle reaches of Hei River in 2000- 2010, in which the ecological environment has been improved, and forest land, grassland area overall in a upward trend.From the change of time for land use / cover in the middle reaches of Hei river, in ten years, a pattern, the area of forest, grassland, urban were increased, scrub and wetlands were first increased and then decreased, the area of the land is decreased first and then increased, and the desert area was decreasing, the area of glacier / permanent snow cover area from the reduced to the same. For the two level pattern, in ten years, these seven types of forest, sparse forest, sparse grass, marsh, garden, residential, industrial and traffic area was increasing, broadleaf shrub, grassland, water, sand area was first increased and then decreased, sparse shrub, meadow, the area of cultivated land is the first to reduce after the increase, saline alkali land and other types of area was decreasing.(2)With the development of urbanization, the pressure of ecological environment on the middle reaches of the Hei River is increasing.(1) From the spatial transfer situation of land use / land cover types in the middle reaches of Hei river, a pattern, in ten years, conversion between the types of the land use mainly concentrated in the forest and shrub and farmland- Town, desert and cropland Grassland- town. For the two level patterns, in ten years, the land use conversion types were mainly concentrated in the other- water- marsh, grassland and arable land, other-saline- Industrial and traffic.(2) From the dynamic changes of landscape pattern in the middle reaches of Hei river, 2000 to 2010 years, the landscape feature matrix for grassland and farmland, desert was maintained in the middle reaches of Hei River, corresponding to two level of landscape pattern, sparse grassland, arable land and other landscape were maintained. From the type of point of view, the grass is of the highest degree of fragmentation, but the trend of fragmentation was decreased, the corresponding two landscape pattern from sparse grass. From weighted fractal dimension grassland, farmland and shrub were greatly affected by human activities, and the influences of the saline alkali soil was very small; from the landscape level, from 2000 to 2010 ten years, the number of patches and patch density were increased at first and then decreased in the middle reaches of Hei river; the average patch area was reduced at first and then increased. On the level of two landscape pattern, the change trend of patch number, patch density and average patch area were keeping with a pattern of landscape level. The one pattern and two pattern of landscape level, contagion index were reduced at first and then increased, the overall to reduce, the patch size decreased, plaque agglomeration degree decreased, landscape fragmentation.(3)The fragmentation of landscape in the study area increased, and the aggregation degree of the patch decreased.(1) From the dynamic change of landscape pattern in the middle reaches of Hei River, from 2000 to 2010 years, the middle reaches of Hei River to maintain the cultivated land and grassland, desert landscape feature matrix, two landscape patterns corresponding with sparse grassland, cultivated land and other landscape. Based on the class level, grassland degree of fragmentation was the highest, but the trend of fragmentation in the two level is reduced, the landscape pattern of sparse grassland, grassland area weighted fractal dimension from the point of view, farmland and shrub, affected by human activities, and is less affected by saline; from the landscape level, from 2000 to 2010 ten years, the number of patches and patch density in the middle reaches of Hei river were first increased and then decreased; the average patch area was decreased and then increased. The number of patch two pattern at the landscape level, the change trend of patch density and average patch area and a pattern of landscape Changes consistent level. Primary and secondary landscape level, contagion index was reduced after the first increase in the trend, generally reduced in most of that patch size decreased, plaque agglomeration degree decreased, landscape fragmentation increased.(2)The landscape pattern of typical counties, from the point of view, the patch density of Ganzhou district is the highest, the landscape is relatively complete, Ganzhou District due to urbanization and other human activities influence are higher, and the natural landscape types were replaced by the artificial landscape, landscape biodiversity minimum. Minle County by the return of cultivated land and grassland, also the effects of the forest engineering, the landscape diversity increased and the degree of landscape fragmentation in decline. Gaotai County landscape is the most significant feature is a decade of wetland landscape types of dramatic changes. slightly.(1)From the watershed ecosystem service function value, the ecological service value was 35.99 billion Yuan, 41.02 billion Yuan and 39.14 billion Yuan, respectively, in 2000, 2005 and 2010, in the middle reaches of the Hei River. The economic value of ecosystem services was increased first and then decreased in the middle reaches of Hei River, but the increase was far greater than the amount. The contribution for farmland and water was highest on ecosystem services value, reaching more than 28%. According to order of the ecological service value, were: water regulation, food production, gas regulation, waste treatment, biological control, pollination, nutrient cycling, and climate regulation > Entertainment > disturbance regulation > water supply > erosion control > raw material > culture > the formation of soil > habitat > gene resource. Due to the change of land type area, all kinds of service function value also change in different degrees.(2)From point of view of ecosystem service function value of the counties, ten years, of the counties in the middle reaches of Hei river ecosystem service value difference larger, Ganzhou, Linze County and Ming Huaxiang service value was increased continuously, Gaotai County and Shandan County service value showed increased and then decreased trend, Minle county service value showed a declining trend. Contribution to the ecological service function value of the largest land type to woodland, water. Ganzhou district and Gaotai County food production value of service function, Minle County water regulation of the service function of maximum value.(5)The characteristics of the surface temperature oasis are prominent, and the vegetation index is negatively correlated with the vegetation index.(1)From the distribution pattern of the land surface temperature in the middle reaches of Hei River, the surface temperature showed obvious temperature characteristics in arid area of Northwest China, that is the vegetation cover of the oasis area high low temperature, high temperature outside of oasis desert area. The study area from southeast to northwest surface temperature was increased, the macro, the surface temperature, the Ganzhou East- Zhangye city- Linze County in the central and western regions in Gaotai County formed in the high value area.(2)Through the statistical analysis of the surface temperature of different land use types, shown that the surface temperature value in 2010 is generally higher than in 2000 for other types of land use value except Glacier, because the image retrieving land surface temperature acquisition time difference, its contribution to the two surface temperature difference rate is very small. In 2000, forest, grassland, desert standard difference, on the whole, consistent with land use / two periods of land surface temperature changes the size of cover types. Using post-hoc multiple comparison method of Tamhane T2 test analysis of surface temperature in any of two kinds of land(4)The value of ecosystem services in the middle reaches of Hei River increased use difference between the types of significant degree, the land use / temperature difference between cover types are significantly(sig.<0.01), only the difference between the farmland and towns is not significant.(3)From the profile lines on the map, vegetation coverage area, there was a negative correlation between land surface temperature and vegetation index, land surface temperature and vegetation index have obvious opposite trend. And the vegetation cover better place two contrast more obvious. From the two periods of change point of view, basically the same profile lines of the two periods of change the shape of the curve, but the surface temperature curve has the overall downward trend in 2010, while the vegetation index curve is the overall upward trend, two curves with central tendency.(4)From 2000 to 2010, the result for the regression of land surface temperature and vegetation index analysis, showed that the maximum absolute value of the linear coefficient in regression function was desert, that is to say with the increase of vegetation index, surface temperature desert decreased most rapidly, in 2000, the second is the smallest forest, grassland and shrub; And in 2010, are the second smallest wetlands, glaciers and the shrub. |
PDF Full Text Request