| Land is the basis for human survival and development.With the rapid development of the social economy,the population is rising,and the demand for land by humans is increasing,so that the land can be further developed and utilized.The evolution of the land use landscape pattern further reflects the way humans change land use.Taking the Taihangshan Qi River Basin as an example,this paper studies the land use status vector data,DEM data and topographic relief data of the Qi River Basin in 1990,2000,2010 and 2015,with the help of ArcGIS 10.2 and Fragstats 4.2.ENVI5.1,Excel2010 and other software.Using land use transfer matrix,land use dynamics model,land use information map,digital elevation model,digital slope model,terrain distribution index,topographic index and landscape index,the land use change and spatial differentiation characteristics of Qi River Basin were carried out.The characteristics of the land use landscape pattern change in the Qi River Basin from 1990 to 2015 were quantitatively described.The gradient characteristics of the land pattern in the Qi River Basin from 1990 to 2015 were analyzed.Based on the evolution characteristics of the landscape pattern of the Qi River Basin,further analysis was made.Corresponding optimization scheme.The main conclusions of this paper are as follows:(1)From 1990 to 2015,the land use types in the Qi River Basin were mainly cultivated land,grassland and woodland.The sum of the three land areas accounted for more than 90%of the total area of the study area,and the sum of the three land areas in the four periods The total area of the Qi River Basin is 95.16%,94.83%,93.23%and 92.01%.The substrate landscape of the Qi River Basin consists of three types of landscape:cultivated land,forest land and grassland.Construction land and waters are two types of land affected by human disturbance.In the four periods,the land area of the two regions accounted for 4.84%,5.16%,6.73%,and 7.95%of the total area of the study area.The area of unused land accounts for less than1%of the research area.In general,the Qi River Basin is dominated by agroforestry.From 1990 to 2015,the trends of cultivated land and forest land were consistent,showing a decreasing state.Especially in 2000-2015,the cultivated land and forest land decreased the most,with a decrease of 129.70 km~2 and 21.07km~2.Grassland,construction land and waters have maintained a continuous growth trend in the past 25 years,and the grassland area has increased the most.It increased by 88.48 km~2 between 2000 and 2015,followed by the increase of construction land,and increased by 42.31 km~2 between 2000 and 2015.The water area was 1990-2000.It has only increased by 0.02%.By 2015,the water area has increased by 19.89km~2,an increase of 0.89%.The area of unused land in the study area is very small,showing a growing trend from 1990 to 2015.(2)The area of cultivated land change was the largest in 1990-2015,with a decrease of 137.19 km~2 in 25 years,mainly converted into grassland,forest land and construction land;the increase of grassland was large,increasing by 88.39 km~2 in 25 years;the forest land showed a decreasing trend with a total decrease of 21.54 km~2.The water area showed an increasing trend,increasing by 20.16 km~2 in 25 years;the main source of construction land was cultivated land,followed by grassland,with a total increase of 49.21 km~2.In the 25 years from 1990 to 2015,the unused land and construction land grew fastest,the land use dynamics were 25.04%and 2.73%;the cultivated land and forest land decreased the fastest,and the land use dynamics were-0.74%and-0.13%,respectively.From 1990 to 2015,the comprehensive index of land use degree in the Qi River Basin showed a downward trend with time.The land use comprehensive index100-200 accounted for the largest proportion in the study area,followed by 200-300,and the land use comprehensive index 300-400 accounted for 300-400.At least,the overall utilization level of the Qi River Basin is at a medium level.From 1990 to 2015,the stable map has the largest area and the widest distribution,accounting for 75.06%of the total area of the study area,followed by the late change map,the intermediate transition map and the iterative map,followed by the continuous change map and The early variants accounted for the least.(3)The LUCC situation in the Qi River basin in the next 10 years may be as follows:the area of cultivated land and forest land continues to decrease,and the area of grassland,water area,construction land and unused land continues to increase.In the past ten years,the social economy of the Qi River Basin is still in a stable development stage.The rapid development of urbanization has led to the construction land to continuously invade other land use types,resulting in a large reduction in cultivated land and woodland landscape.(4)As far as the topographic gradient distribution of land use structure is concerned,cultivated land,construction land,grassland and water area are mostly located in low altitude,small slope and low terrain relief area,and the forest land is in high altitude,large slope and high relief area.Distribution of land use change on elevation gradient:In low-altitude areas,the area of cultivated land decreased,and the area of grassland,water area and construction land increased.In the mid-altitude area,the area of grassland and woodland is reduced.The increase of forest land area is mainly in high altitude area;the dominant distribution interval of cultivated land,grassland and construction land has not changed,the spatial distribution pattern of forest land has changed significantly,and the dominant distribution range has gradually narrowed to high terrain gradient.Distribution of land use change on slope gradient:in low slope areas,the area of cultivated land decreased,the area of construction land and forest land increased; grassland and water area were always in an increasing state;the distribution index of cultivated land,forest land,grassland,water area and construction land remained basically stable.There is no change in the dominant distribution interval.The distribution of land use change on the undulating gradient:in the low-lying relief area,the area of cultivated land is decreasing and the area of construction land is increasing.In the middle and high topographical areas,the area of cultivated land is still decreasing,the area of forest land is decreasing slightly,water area,grassland and construction The land area continues to increase;the dominant position of cultivated land,water area and construction land is distributed on the 0-30m and 30-70m terrain fluctuation level,and the grassland dominant position is concentrated in the 70-200m terrain relief zone,and the forest land is above 70-200m and above 200m.The range of fluctuations is the dominant category.(5)In the degree of landscape fragmentation,the degree of landscape fragmentation in the study area intensified from 1990 to 2010,and it was moderated and reduced in 2010-2015.In terms of aggregation degree,the 25-year“distributed-aggregated”state,dispersed in 1990-2010,the degree of cohesion decreased,internal connectivity decreased,the degree of dispersion decreased in 2010-2015,connectivity increased,and more concentrated,but for 25 years,landscape The spread index is decreasing and the connectivity of the dominant landscapes in the study area is reduced.From the aspect of shape change,1990-2000 tends to be irregular and complex,and 2000-2015 tends to simple rules.In terms of landscape diversity,the 1990-2015 Fragrance Index and Fragrance Uniformity Index continued to rise,indicating that the landscape diversity of the study area increased,and the obvious dominant types and plaque types were evenly distributed in the landscape. |
PDF Full Text Request