Assessment Of Bird Habitat Quality In Areas Of The Lower Reaches Of Huolin River Basin

The lower reaches of Huolin River Basin is located in the ecotone of agriculture and animal husbandry in northern China.It is an important supply water source for many national nature reserves such as Horqin wetland and Xianghai wetland.Over the past few decades,excessive land development and utilization has led to the drying up of many lakes in the basin,the degradation of various habitats,and the sharp reduction of the number of many common bird species.These ecological problems have seriously affected the sustainable development of local economy and society.This paper selects the lower reaches of Huolin River Basin as the study area,takes birds as indicator organisms,and analyzes the temporal and spatial variation law of habitat quality and its correlation with the evolution of landscape pattern in the watershed ecosystem based on invest model and geographic information technology,in order to provide scientific reference for the ecological restoration work in the watershed ecosystem in China in the future by quantifying the impact of human activities on habitat quality and understanding the interaction between human activities and habitat,The results show that:(1)From 2000 to 2020,human activities in the study area showed an expanding trend.The grassland area continues to decrease,and the cumulative net transfer area is1410.21km2,which is mainly transformed into cultivated land,and some grasslands are degraded into other land types;The change range of cultivated land,other land types and water area is smaller than that of grassland,showing an upward trend.The cumulative net transfer areas of the three are-675.83km~2,-503.80km~2and-169.48km~2respectively;The area of forest land and construction land has not changed significantly;Thanks to the implementation of relevant local policies,many grasslands and other land types in the study area have been restored to water areas.(2)In terms of pixel area proportion and variation range on each Habitat degradation degree level,the habitat degradation degree in the study area from 2000to 2020 was mainly micro degree,followed by mild degree,and the area of severe degradation grade was the least.The habitat degradation index gradually decreased radially to the radiation direction with the construction land as the center.The area of high and severe degradation showed an upward trend,the area of moderate degradation first decreased and then increased,and the area of slight and mild degradation tended to be stable;In terms of pixel area proportion and variation range on each habitat quality level,the pixels with better habitat quality grade accounted for the largest area in the study area from 2000 to 2020,with the area proportion of three phases being 47.49%,47.94%and 52.68%respectively,followed by the pixels with good habitat quality grade,with the area proportion of three phases being 40.78%,37.07%and 31.49%respectively.The pixels with poor habitat quality grade ranked in the middle,and the area proportion of pixels of the other two habitat quality grades was very small,The distribution characteristics of each habitat quality grade in each district and county are basically consistent with the total distribution characteristics of habitat quality grade.The change range of pixel area with good habitat quality grade is the largest and shows a gradual decreasing trend.It decreased by 3.71%from 2000to 2010 and 5.58%from 2010 to 2020.The change range of pixel area with good and poor habitat quality grade is the second,and they show a gradual increasing trend.The change rate tends to zero due to the small proportion of pixel area of the other two habitat quality grades.(3)From 2000 to 2020,the habitat quality of nearly half of the regions within the research scope has changed,and the habitat quality has an obvious trend of improvement;From the perspective of land cover types,the habitat quality grade area of cultivated land has the largest change range,among which the habitat quality grade of cultivated land has improved from 2000 to 2010 is 3574.14km~2,and from 2010 to2020 is 3574.14km~2,followed by grassland and other land types.The habitat quality of other land cover types has little change or accounts for a small proportion in the past 20 years;The changes of habitat quality and landscape pattern show a certain correlation.When the landscape pattern changes sharply,the habitat quality will deteriorate accordingly,When the variation rate of habitat quality increases,human land development activities are also more intense.