Study On Landscape Fragmentation Of The Habitats For Waterfowl In Zhalong

Zhalong nature reserve is an important habitat for red-crowned cranes and other rare waterfowl.With the development of urbanization and the increase of population in China,human activities have seriously threatened the reproduction of waterfowl living in zhalong,and the habitat fragmentation of waterfowl is one of the threats.In order to protect the species diversity of zhalong waterfowl,this paper classifies the landscape of zhalong conservation area according to the characteristics of habitat selection of waterfowl,obtained the habitat landscape classification data of zhalong waterfowl in 1990,2000,2010 and 2017.Landscape index model,the effective mesh size model and fracturing spatial process model based on Forman theory were used to study landscape patch characteristics,spatial and temporal distribution characteristics of degree of fragmentation and spatial process characteristics of zalong waterfowl habitat.In the research process,the main results are as follows:(1)The heavy marsh habitat always occupies the central position of zhalong protection zone,the light marsh habitat wraps around the periphery of the heavy marsh habitat,and the grassland and disturbed habitat are distributed in the northwest,southeast and southwest parts of the protection zone;The northwest and southeast grassland habitats have been expanding.(2)Between 1990 and 2000,the habitat landscape changed the most and the phenomenon of drought was obvious;After 2000,the phenomenon of habitat drought was alleviated,but salinization occurred.(3)During the study period,zhalong habitat landscape patch fragmentation tended to be serious;Light bog and heavy bog habitat shrink as a whole and the distribution of light bog landscape elements becomes increasingly discrete.All kinds of habitats are disturbed by human activities.The degree of habitat fragmentation of the center of the reserve is low,and the parts in the north,southwest,southeast and the boundary are seriously broken,and the trend is aggravating.(4)In each period of time,the increasing degree of fragmentation of the protected area is always larger than the alleviated area;But over the entire time series,the fragmentation increases and the area decreases.Along the disappearance direction of the river,zhalong habitat fragmentation degree is low;The west-east trend shows an inverted "V".(5)From 1990 to 2000,a large area of marsh habitat island in the northwest of the reserve disappeared;During the whole research period,the area of the patches in the re-segmentation process gradually increased,and finally became the habitat fragmentation mode that paid equal attention to the shrinking process in the habitat.(6)The habitat structure in the 126-185 elevation region is unstable,and the habitat fragmentation changes most dramatically in the 135-143 m elevation region.Precipitation has certain influence on habitat fragmentation degree in the reserve.The fire in the protected area directly causes the habitat and food loss of aquatic birds in the protected area,which is also the main reason why the habitat began to increase the area of saline-alkali land after 2000.The protection policy for zhalong has effectively alleviated the phenomenon of habitat fragmentation.