Farmland Landscape Pattern Change And Its Ecoenvironmental Effects In Dongting Lake Ecological Economic Zone

Dongting lake ecological economic zone including Yueyang city,Chang de city,Yiyang city,Changsha city of Hunan province,Jingzhou city of Hubei province and other areas,is approved by the state council in 2014 of countries and directives.Taking Dongting lake ecological economic zone Landsat TM remote sensing image in 1990,2000,2010,2000 year as the main source of information,using ArcGIS software interpretation and Fragstats landscape index and SPSS19.0 correlation analysis,according to the real-time monitoring data of water quality and soil in the lake district,the change of farmland landscape pattern and its ecological environment effect in the ecological economic zone of Dongting lake were preliminarily analyzedThe main research results show that:?1?Analysis on the change of farmland landscape type area:From 1990 to 2016,farmland landscape area continued to decrease by 1.50%,among which,both paddy field and dry land area decreased in farmland classification,and decreased by 1.37%and 0.74%respectively.Farmland area accounts for more than 37%of the total area of the study area.During the study period,the area of lakes,rivers,construction land and unused land increased by 0.50%,2.54%,30.40%and 6.66%respectively,while the area of farmland,woodland and grassland decreased by 1.5%,0.36%and 7.17%respectively.?2?Analysis on the change characteristics of farmland landscape index:According to the Fragstats classification standard,the corresponding indicators were selected to analyze the landscape index of the ecological economic zone of dongting lake.From 1990 to 2016,the complexity of lakes and rivers was weakened,and the connectivity was enhanced.The degree of farmland connection and agglomeration is weakened,and the landscape pattern tends to be scattered.The number of patches of dry land and paddy field in the lake area was the highest,both of which maintained at over 900,and the area of paddy field decreased by1.37%in 26 years.The number of dry land patches?NP?is the largest,and the value of the boundary density?ED?of dry land is second only to that of woodland and paddy field,indicating that the dry land is strongly disturbed and highly fragmented.?3?Analysis on driving force of farmland landscape pattern change:Including population factors,urbanization,industrial development,government macro-control and so on.From 2000 to 2016,the urbanization of dongting lake eco-economic zone increased by48.82%,the industrial output value increased by 7 times,and the farmland area decreased by1.27%.Urbanization grew by an average of 3.05%a year,the annual average decline of0.08%farmland area,C<1 indicates that farmland area to reduce the size of the amplitude is less than the urbanization level of growth,dongting lake ecological economic zone in the urbanization process of farmland resources reasonable use.?4?Analysis of farmland landscape pattern and eco-environmental effects:Using SPSS19.0 to analyze the correlation between landscape type area and farmland landscape pattern index of Dongting Lake eco-economic zone and water quality index of dry?flood?water period,and to study the water quality of the area there are some linkage changes with other landscape pattern parameters.The farmland landscape as the main source of pollution output is positively correlated with the water quality of pH,COD_Mn,NH₃-N,while it is significantly negatively correlated with DO,indicating that the farmland causes non-point source pollution;farmland landscape there was a correlation analysis between the pattern indexes NP,LPI,PAFRAC,CONHESION,AI,ED,PD and the dry?flood?water quality.According to the soil data,such as basic farmland,vegetable base and drinking water source,the comprehensive pollution index of 1 points in the research area of basic farmland soil was2.137,the pollution grade was moderate,6.7%,and the other points were all clean level,and the 2 points of the main vegetable base were mild.Pollution,accounting for 13.3%,all of them are clean and clean,and the soil surrounding the centralized drinking water source is clean and clean according to the two grade standard of soil environmental quality.