Study On Landscape Pattern And Connectivity Dynamic Changes Of River Corridor In Changsha

To understand river corridor dynamic changes of landscape pattern and connectivity in Changsha, using vector data as the foundation in 1990, 1995,2000,2005,2010 and 2014 year in Changsha, to obtain data along the river corridor under the GIS support, to calculate landscape pattern index and connectivity index with Fragstats3.3 and Conefor Sensinode2.2 software, and analyze the reason of landscape index changes, then analyze the difference of landscape pattern in Changsha regional. The main results are as follows:(1)The CA, NP and AI is downward trend, DIVISION is rising trend, that reflect patch fragmentation is degree deepening, among them, the patch fragmentation of green river corridor is more serious.(2)Climate factors as precipitation, temperature and evaporation changes will affect the increase or decrease of landscape patch area. Construction land takes up water, the reason is that population growth, and policy changes and urban planning changes directly affect the change of river corridor landscape pattern.(3)The river corridor is made up of a large number of small plaque and a small number of large patches of giant plaque. Giant plaque is the main source of landscape connectivity core plaques. Landscape connectivity index value all shows the tendency of decrease under different threshold setting. Landscape connectivity core area is decreasing. The main reason is that the number of small area patches has been reduced, and the giant patches are divided into large and medium-sized patches, which makes connectivity taken a knock.(4)To compare landscape pattern and connectivity index value of river corridor in Changsha including six districts, two counties and one county-level city. The results show that:the NP in Liuyang, Ningxiang, Xingsha and Wangcheng is more. SHAPE-MN and SPLIT is higher. AI and connectivity index is low. LPI, AI and connectivity index is higher, SHAPE-MN, AI and DIVISION is low in Kaifu, Yuelu, Tianxin, Furong and Yuhua. The main factors affecting of landscape index space difference is the terrain, planning and population. The terrain is relatively flat in Kaifu, Yuelu, Tianxin, Furong and Yuhua. This area is densely populated and key development areas. The river corridor by human disturbance is larger. The terrain is relatively rugged in Liuyang, Ningxiang and Changsha County. Rivers shape is irregular. This area is sparse populated and the river corridor by human disturbance is lesser.(5) River corridor landscape patch area is declining, and patch fragmentation degree is deepening, and landscape connectivity index value is decreasing, and the connected core area is reducing. Suggestions such as prevent water degradation, strengthening the protection of important ecological corridor control, strengthening the plaques, ecological node protection, repair the optimization countermeasures have been put forward to protect the river corridor.