Influencing Factors Of Ecosystem Functions In Coastal Wetlands Dominated By Suaeda Salsa

Ecosystem management policies increasingly emphasis on providing multiple functions rather than individual ecosystem function.In order to study the impact mechanism of ecosystem function at the coastal wetland in community level,this paper takes Suaeda salsa communities as the research object in the Yancheng National Nature Reserve and Dafeng Milu National Nature Reserve.Community investigation was conducted to study the effects of soil factors and animal disturbance factors on individual ecosystem function(above ground net primary productivity,nutrient cycle,and litter decomposition).The ecosystem multifunctionality was quantified by averaging the above ecological function indexes after standardization,and to explore the impact of the soil properties and animal disturbance on the ecosystem multifunctionality of the Suaeda salsa community.The main findings were as follows:(1)The vertical distribution of soil characteristics of Suaeda salsa communities in different ecosystems was consistent.The soil electrical conductivity,total carbon,organic carbon,total nitrogen,ammonia nitrogen,nitrate nitrogen and available phosphorus basically showed a decrease with depths;The soil moisture increased first and then decreased with depth;p H and total phosphorus were relatively stable among the three soil levels.In addition,the differences in soil characteristics between research systems generally decreased with increasing depth.(2)The correlation between aboveground biomass and vegetation coverage in the Suaeda salsa communities in coastal wetland is extremely significant,but not significantly related to vegetation coverage.Animal disturbance indicators(crab burrowing density and mean distance of nearest neighboring burrows)varied greatly between systems.(3)Soil moisture and soil electrical conductivity were important factors affecting the carbon cycle index.The effect of system heterogeneity on the carbon cycle index was mainly reflected in the 10 ~ 60 cm soil layer.Soil moisture was an important factor affecting the nitrogen cycle index.Different research systems had little effect on the nitrogen cycle index.Soil electrical conductivity was an important factor affecting phosphorus cycle index,and the influence of system heterogeneity on phosphorus cycle index was mainly reflected in the 10 ~ 60 cm soil layer(especially in the 10 ~ 30 cm soil layer).(4)The effects of soil factors,animal disturbance factors and system heterogeneity had no significant effect on above ground net primary productivity and litter decomposition.(5)Soil moisture,soil electrical conductivity,crab burrowing density and mean distance of nearest neighboring burrows had a positive effect on the multifunctional index,while p H had a negative effect on the multifunctional index.Only the soil layer with soil electrical conductivity in the 10 ~ 30 cm soil layer had a significant effect on the multifunctional index.(6)The effect of each influencing factor on the multifunctionality index in the 3 soil layers was a comprehensive reflection of the effect on each individual ecosystem function,which would obscure the effect of each influencing factor on individual function;In the 0 ~ 60 cm soil layer,the positive effects of soil moisture and soil electrical conductivity on the multifunctionality reached a significant level.In general,there was a consistent vertical distribution pattern of soil indexes among different research systems.Soil moisture content and soil electrical conductivity were important factors affecting the nutrient cycle.The effect of each factor on the ecosystem multifunctionality was a comprehensive reflection of the effect on each individual ecosystem function.This study can provide a reference for understanding ecosystem multifunctionality at the community level.