Effect Of Landscape Pattern Change On Bird Diversity In Anhui Anqing Caizi Lake National Wetland Park

Birds are one of the important components in the wetland ecosystem,which play an important role in maintaining the stability of the ecosystem and are extremely sensitive to the changes of the environment.Bird diversity can reflect the bird community structure and habitat conditions,and is one of the important indicators of wetland ecosystem quality.The habitat conditions of wetlands directly or indirectly affect the abundance,richness,and spatial distribution of bird communities,and then determine the diversity of bird communities.At the landscape scale,bird community structure is determined by habitat patch size and landscape type diversity.The higher heterogeneity of wetland habitat,the more birds can inhabit it.Wetland landscape pattern with seasonal changes directly affects bird community diversity.Understanding the responses of birds to changes in landscape patterns is the basis for enhancing conservation and management of wetland birds and their habitats.In this paper,Anhui Anqing Caizi Lake National Wetland Park was chosen as research area,by aid of the grid units,bird surveys were conducted from August 2019 to January 2020 and August 2020 to January 2021.Based on remote sensing images,using ENVI 5.3,Arc GIS 10.2 and Fragstats4.2,the changes in landscape pattern within grid cells were identified.Finally explored the relationship between birds and the landscape pattern of habitats.The main results are as follows:1.There are 106 species of birds,belonging to 15 orders and 40 families.A total of 67 species,30 families,were recorded in the high-water period,of which 54.55% were Passeriformes and 12.12% were Ciconiiformes.During the low-water period,79 species of 21 families of birds,32 species of Passeriformes,13 species of Anthiformes,12 species of Charadriiformes were recorded.In terms of the number of birds,and the Passeriformes birds are the dominant ones,in high-water period.In low-water period,the wintering waterbirds are the main birds,and the Anseriformes are the dominant species.2.The temporal and spatial dynamics of bird diversity vary significantly with months.There are more birds in the southern part of the wetland park during high-water period.After entering the low-water period,birds are concentrated in the northern part of the wetland park.Among them the northern part of the ecological conservation zone has the largest number,the number of birds in the southern part is relatively reduced,and only a few birds are distributed in the central of the wetland park.The number of birds in the ecological conservation zone has obvious seasonal dynamics.The number of birds recorded in the high-water period is less,and the number of birds recorded in the wintering season is the largest.The diversity index of each functional zone in the high-water period are higher than that in the low-water period.The diversity index of the ecological conservation zone decreased significantly between seasons,and the diversity index of the rational utilization zone is significantly higher than the others during the entire survey period.3.From the high-water period to the low-water period,the landscape heterogeneity of wetland park increased.The characteristics of landscape changes in the two periods are that the area of water decreased monthly,and the area of mudflats and grassland increased significantly after entering the low-water period.The water area reaches the highest proportion of 83.62% in the high-water period,and gradually decreases to 44.06% in the low-water period.At the landscape level,after entering the low-water period,the fragmentation index,landscape diversity index and evenness index increased significantly,while the sprawl index decreased.Combined with the specific ecological significance of each landscape index,the changes of these indexes indicated that during this period,the landscape pattern of Caizi Lake National Wetland Park became fragmented and complicated and the water landscape advantage decreased.The degree of landscape heterogeneity has increased.4.The main landscape factors affecting the diversity of terrestrial birds and wintering waterbirds are different.In the high-water period,landscape fragmentation,evenness and diversity index were the main landscape factors affecting the distribution of common land birds in the wetland park.In the low-water period,the distribution of wintering waterbirds was mainly affected by the area of mudflats,grassland and water patch.