Land Use/Cover Change And Its Impact On Habitat Suitability Of Giant Panda Distribution Counties In Sichuan Province

Giant panda(Ailuropoda melanoleuca)is a flagship species for global biodiversity conservation,however,due to natural factors and human activities,the habitat loss and fragmentation are the greatest threats to its long-term survival.Based on the current survival and conservation status of giant pandas,research on the effects of human disturbances on the suitability and connectivity of giant panda habitats and the relationship between them is carried out.It is essential for the conservation of giant panda populations and habitats,and for maintaining the integrity of ecosystem functions.Land use/cover change acts as one of the main drivers affecting biodiversity distribution patterns.Currently,the relationship between dynamic land-use change and species conservation still needs to be explored in depth.Therefore,it is crucial to analyze the impact of land use dynamic changes on giant panda habitat.In this study,37 counties(cities and districts)where giant panda habitats are located were selected as the study area.Based on the analysis of land-use dynamics,we evaluated the changes in habitat quality.Then,the third,fourth national and field infrared camera giant panda distribution point data were used to evaluate changes in the suitability and connectivity of giant panda habitats,which combined with climate,topography,vegetation and anthropogenic disturbance factors.Finally,a paired t-test was used to test whether habitat suitability and connectivity changed under land-use transformation.Moreover,we explored the effects of socioeconomic development,land use/cover change on habitat suitability and connectivity of giant pandas and the relationship of their association by using stepwise regression analysis.The results showed that:(1)The forest land(+0.69%),construction land(+0.30%)and water area(+0.18%)increased while grassland(-0.89%)and cultivated land(-0.28%)area decreased in the study area,which showed a shifting pattern of the land use.The dynamic degree of land use in each county ranges from 0.01%to 0.36%,indicating that the rate of land use change is relatively slow and the degree of land use varies widely,with Anzhou district,Chongzho,Muchuan,Pengzhou,Shifang and Shawan Counties having the greatest degree of land use with values greater than 250.(2)The spatial quality of habitat decreased from west to the east,with the area of improving habitat quality(952.35 km~2)being smaller than that of decreasing(1,562.38km~2).But the habitat quality within the giant panda habitat remained stable.The degree of degradation of the overall habitat quality showed an increasing trend,and the mean value of habitat degradation index increased from 0.018 in 2000 to 0.022 in 2020.Moreover,the quality of habitats in areas with high degree of habitat degradation in space was also low,and vice versa.The variation range of quality and landscape fragmentation was roughly in the same spatially.In areas with high landscape fragmentation,the habitat quality was lower.(3)The spatial distribution pattern of habitat suitability for giant pandas is high in the middle and low in the surroundings.16,039.92 km~2 of suitable habitat in 2000 and15,599.88 km~2 of suitable habitat in 2020.The spatial distribution pattern of connectivity of giant panda habitats was more or less the same across time,with the high connectivity mainly occurring in the protected areas.The places where connectivity increased significantly were mainly in Pingwu,Qingchuan,Baoxing and Shimian Counties.In contrast,there is a risk of decreasing habitat connectivity at the borders of Jiuzhaigou and Pingwu Counties,Beichuan and Mao Counties,southern Wenchuan County,and Ganluo,Ebian and Meigu Counties.(4)Under different land-use conversions,habitat connectivity almost always increased significantly from 2000 to 2020,and suitability showed different positive or negative changes.It occurs mainly in areas where other types convert to land types such as grassland and water.(5)There was a significant positive correlation between habitat suitability index changes and land use degree changes,and an opposite trend between changes in regional primary industry values.The connectivity index variation showed a significant positive correlation with the change of secondary industry value and a significant negative correlation with the change of total population,but there was no significant linear relationship with the land use factor.