Study On The Spatial Distribution And Environmental Difference Of Tropical Forest Plant Communities In Xishuangbanna Based On Reproductive Traits

In the past,the study on plant community assembly is mainly based on species composition,the relationship between communities and environmental factors.In recent years,the functional traits such as leaf traits,trunk traits are also used to study community assembly.However the plant regeneration and the completion of plants individual life history depend on the plant reproduction process.Because of different kinds of plants adopt different reproduction methods to maintain the continuation of their populations and form a diversified plant community assembly.This study aims to reveal that plant reproductive traits can directly reflect plant community assembly and ecosystem processes than other plant traits.Therefore,the study focuses on the tropical forest plant community under different environmental factors in Xishuangbanna.We investigated 69 plots of 20m×20m plant community,sixteen reproductive traits,eight leaf traits,two trunk traits,and thirteen environmental factors.Firstly,the clustering method was used to divide the plant communities into three plant communities.The article analyzed the species composition and environmental differences in different plant communities.Furthermore,The article analyzed the relationship between different reproductive traits and other functional traits,and the main environmental impact factors.Finally,based on the main reproductive traits,the paper was reconstructed the main pattern of plant community assembly by using the null model,tested the contribution of habitat filtration,competitive inhibition and random effects to plant community assembly.The main study results show that:(1)The environmental factors influenced plant community assembly mainly including elevation and recovery time,followed by canopy openness,slope,soil water content,soil available potassium,soil total phosphorus,and soil pH.Community ? was mainly distributed in the environmental factors such as longest recovery time and the lowest elevations.Community I had the lowest canopy openness,moderate soil available potassium,soil pH and soil water content,and the highest total soil phosphorus.The main species were Parashorea chinensis,Pometia tomentosa,Pittospporopsis kerrii,and Saprosma ternatum,etc..The indicator species were Baccaurea ramiflora,Dysoxylum excelsum,and Saprosma ternatum,etc..Community ? was mainly distributed in the environment of shortest recovery time and medium elevation.Community II had the highest canopy openness and soil water content,and the lowest soil available potassium,soil total phosphorus and soil pH.The main species were Castanopsis echinocarpathe,Phoebe puwenensis,Ficus altissimaalpine,Garcinia cowa and Engelhardtia sppicata.The indicator species were Litsea pierrei Lec.var.szemaois Liou Ho,Garcinia cowa,Ardisia quinquegona Bl.,etc..Community ? was distributed in the environment of the shortest recovery time and highest altitude,and the lowest canopy openness and soil water content,the highest soil available potassium,soil pH value,and medium soil total phosphorus.The main species were Machilus tenuipila,Castanopsis mekongensis,Aporusa yunnanensis and Pittospporopsis kerrii,etc..The indicator species were Castanopsis mekongensis and Castanopsis echinocarpa.(2)The plant functional traits influenced plant community assembly mainly including reproductive traits,followed by leaf traits,while the trunk traits were lowest.Among them,the fruit types were correlated with fruit shape,fruit color,inflorescence position,flower color,flower sex and seed dispersal.Inflorescence types were correlated with inflorescence position,flower color and seed dispersal.The specific leaf area was correlated with leaf nitrogen and phosphorus content.(3)Community ? had the largest fruit and seed.The dispersal mode of seeds were mainly winged and anim2.Their fruits had berry,capsules and drupe.Most of the flowers were bisexual,and the inflorescence types were cyme,raceme and hypanthium in axillary.Community ? and Community ? had the relatively small fruit and seed.The dispersal mode of seeds were mainly winged,auto and anim1.The fruit types were capsule and nut.Most of the flowers were unisexual and polygamous,and the inflorescence types were cyme,raceme,umbel,capitulum,cone and spica etc..(4)The environmental factors influenced reproductive traits mainly includingelevation and recovery time,followed by canopy openness,slope,soil moisture,total soil phosphorus and soil pH.Among them,the environmental factors influenced fruit traits mainly including elevation,recovery time,canopy openness,soil total phosphorus and soil available potassium etc..The environmental factors influenced dispersal mode mainly including canopy openness,soil pH,soil organic matter and soil total phosphorus etc..The environmental factors influenced flower colors mainly including elevation,recovery time,canopy openness,soil water content,soil total phosphorus and total potassium etc..(5)In community ?,competitive inhibition was mainly community assembly,secondly habitat filtering and random effects.In community ? and community ?,habitat filtration was mainly community assembly,secondly competitive inhibition and random effects.Among them,In community II the main limiting factors were soil pH and soil total phosphorus.In community III,the main limiting factors of habitat filtration were soil organic matter,soil water content and soil total phosphorus.