Estimation Of Soil Calcium Spatial Distribution In Karst Areas And Analysis Of Its Impact On Plant Species Diversity

The special karst geological background makes the soil in karst areas very calcium-rich.As a ubiquitous environmental factor in karst areas,soil calcium plays an important role in the karst ecological environment.In terms of maintaining plant species diversity,calcium environmental factors Its ecological function cannot be ignored.As an important landmark for global biodiversity conservation,karst areas harbor extremely rich biodiversity under their unique ecosystems.This paper takes Guizhou Province as the research area,combined with the surface soil total calcium data,plant species diversity data,remote sensing data,climate data,topographic data,economic data,lithology data,etc.Factor data,using geographic weighted regression model,linear trend analysis,geographic detector and stepwise linear regression analysis and other methods,to carry out the estimation of soil calcium spatial distribution in karst area and the analysis of its impact on plant species diversity,in order to further reveal the indicators of karst area.The spatial distribution characteristics of soil calcium in a calcium-rich environment and its mechanism of formation and maintenance of plant species diversity provide theoretical support and accumulation of basic data.The main conclusions of the research at the end of the article are as follows:(1)The GWR model was used to effectively estimate the spatial distribution of total calcium in the topsoil of Guizhou Province.The overall level of total calcium in the topsoil of Guizhou Province was relatively high and the spatial heterogeneity was strong.Lithology and slope are the dominant factors affecting the spatial distribution heterogeneity of total calcium in topsoil.The GWR model has better reliability and accuracy than the traditional least squares regression in the estimation of the spatial distribution of total calcium in the topsoil of Guizhou Province.The estimated total calcium in the topsoil varied from 1.045 g/kg to 28.437g/kg,with an average value of 11.38 g/kg.The overall content level was high,and the spatial heterogeneity showed moderate variation.Lithology and slope are the dominant environmental factors affecting the spatial distribution pattern and heterogeneity of total calcium in topsoil.The total calcium content of the bottom layer of the limestone background is the highest,the total calcium content of the bottom layer of the clastic rock background is the lowest,the total calcium content of the bottom layer of the 0-10°slope grade is the lowest,and the bottom layer of the 40-50°slope grade has the highest total calcium content.(2)The overall level of vegetation coverage in Guizhou Province is relatively high.In the past 20 years(2000-2019),the vegetation coverage has increased significantly,and the regional vegetation restoration effect is remarkable.The distribution of vegetation coverage is mainly dominated by medium,medium-high and high coverage,the sum of which is about89.7%,the average annual growth rate is 0.5%,and the average vegetation coverage is 0.53.In the past 20 years,the trend of vegetation coverage has been slightly improved and basically unchanged.The sum of the two areas accounts for 68.94%,and the area of the improved area accounts for 57.93%.The western area has improved significantly,and the degraded areas are more concentrated around towns and cities.,the overall dynamic trend is stable and tends to improve.(3)Vegetation restoration in Guizhou Province is deeply affected by both socioeconomic factors and natural environment factors,and socioeconomic factors have a stronger impact on regional vegetation restoration than natural environment factors.Active human activities have made great contributions to vegetation restoration in Guizhou Province.In terms of socio-economic factors,GDP is the dominant factor in maintaining vegetation restoration in Guizhou Province.In terms of natural environment factors,precipitation is the dominant factor in maintaining vegetation restoration in Guizhou Province,the most suitable ranges for the two to maintain FVC recovery are RMB 2.124-94.317billion and 1422.8-1645.36 mm.Actively promoting the optimization and upgrading of the industrial structure,vigorously promoting the rapid development of the tertiary industry,and continuously implementing the policy of returning farmland to forests and grasslands have made great contributions to the improvement of vegetation in Guizhou Province.(4)Soil calcium plays an important role in maintaining plant species diversity in karst areas,but soil calcium does not play a dominant role in maintaining plant species diversity in karst areas,but maintains calcareous endemic species of plant species diversity in karst areas.With a leading role,the maintenance of regional plant species diversity mainly depends on the restoration of vegetation under the interaction of active human activities and unique natural environment.Under the Maolan primitive karst forest,the plant species diversity was significantly positively correlated with soil calcium and vegetation coverage,and the plant species diversity and both were significant at the0.01 level.0.826 and 0.598,R~2 was 0.682 and 0.58,respectively.Soil calcium had a greater contribution to the maintenance of calcareous endemic species and regional plant species diversity.In the degraded karst forests of Maotiao River and Nanming River in Guiyang,the plant species diversity only has a significant positive correlation with vegetation coverage,and it is significant at the 0.01 level,the Pearson correlation coefficient is 0.875,and the R~2 value is 0.765,while soil calcium and plant species diversity were not significant at either the 0.01level or the 0.05 level,and soil calcium did not play a dominant role in maintaining plant species diversity in the region.In general,the maintenance of regional plant species diversity in karst areas mainly depends on the restoration of vegetation under the interaction of active human activities and unique natural environment.