Patterns And The Correlative Factors Of Soil Physic-chemical Properties Of The Masson Pine(Pinusmassoniana)Forests In The Fragmented Of The Thousand Island Lake

Soil is an important part of the forest ecosystem and plays an irreplaceable role in the maintenance of forest biological diversity and ecosystem function.Understanding the spatial distribution pattern of soil physical and chemical properties and its determinants in fragmented landscapes is of great significance for speculating on the impact of habitat fragmentation on forest ecosystems.Therefore,this study aimed to study the effects of habitat fragmentation on soil physical and chemical properties of Masson pine forests in the continental(35 plots)and 29 bridge islands(plots).The results showed that:(1)The principal component analysis(PCA)and t-test showed that there was significant difference in soil physical and chemical properties between the island and adjacent continent.The soil thickness of Masson pine forest was significantly higher than island,while the maximum soil water content was significantly lower than island.The total P(Phosphorus)of soils in the mainland was significantly lower than islands while the available phosphorus(AP)and nitrate nitrogen(NO3--N)was significantly higher than that islands.(2)The effect of island environmental factors on soil physical and chemical properties was analyzed by linear mixed effect model.We found that the content of C,N,P,NO3-N and AP in soil decreased with the increase of the distance from the edge of the island.The island isolation and topography affected some soil physico-chemical factors,while the island area had no effect on the soil physical and chemical properties.There was a significant correlation between soil physico-chemical factors and plant community diversity.Habitat fagmentation changed the soil conditions of Pinusmassconiana forest in The Thousand Island Lake,and the edge effect may be one of the main processes controlling the spatial distribution of soil properties in fagmented habitat.(3)The linear mixed effect model is used to analyze the influence of terrain on the soil in the mainland.We found that with the elevation increasing,the content of total N and the maximum water holding capacity decreased,and the soil ammonium nitrogen and soil density increased With the increase of slope,the soil total phosphorus increased,the soil available P and soil thickness decreased.With the slope toward the east,the content of total phosphorus and nitrate nitrogen in soil decreased,the total nitrogen,ammonium nitrogen and soil thickness increased.Topography has no effect on soil total P,ammonium nitrogen,soil density and maximum water holding capacity.(4)The linear mixed effect model was used to analyze the influence of topography factors and fragmentation on the physical and chemical composition of soil We found that with the aggravation of fragmentation,the soil total nitrogen and soil density increased,the soil ammonium nitrogen,nitrate nitrogen,maximum water holding capacity and soil depth decreased.With the increasing of altitude,soil total nitrogen,nitrate nitrogen,available phosphorus and soil depth decreased,while ammonium nitrogen and maximum water holding capacity increased.With the increasing of slope,total nitrogen,ammonium nitrogen and available phosphorus increased,soil depth decreased.As the aspect increases more northward,the soil ammonium nitrogen and available phosphorus increased,and the soil nitrate nitrogen and maximum water holding capacity decreased.As the aspect is more eastward,soil total nitrogen and maximum water holding capacity increased,while soil nitrate nitrogen,soil depth and soil density decreased.(5)On the islands,the indicators which influence the biodiversity of Pinusmassoniana forest(such as Simpson index and Shannon-Wiener index)are soil nitrate nitrogen,available phosphorus and soil density.In mainland,the indicators which influence the biodiversity are soil phosphorus,ammonium nitrogen and soil density.This study deepens the understanding of how habitat fragmentation affects soil conditions and is of great significance to the formulation of forest management measures in the context of habitat fragmentation.Soil is an important part of forest ecosystem,and the study of soil physical and chemical properties has deepened the understanding of forest biodiversity and ecological function.