高原鼢鼠鼠丘植被群落物种多样性与生产力的耦合格局及环境调控OA

The relationship between species diversity and productivity remains a central theme in contemporary ecological research.As natural"disturbance gradient platforms,"the molehills created by the plateau zokor(Myospalax baileyi)provide a unique opportunity to study the dynamics of species diversity and productivity during plant community assembly.In this study,we investigated molehills of varying ages within grazing-excluded plots in alpine meadows on the eastern Qinghai-Tibet Plateau.We analyzed the patterns of plant species diversity and temporal changes in aboveground,belowground,and total biomass.By measuring key soil physicochemical properties,we identified the primary drivers influencing vegetation succession on these disturbed microsites.The results indicated that:(1)With increasing succession duration,there were significant differences in soil bulk density,soil moisture content,organic carbon,and the carbon-to-phosphorus ratio among the different years.Among these,the total phosphorus,organic carbon,and the variations in perennial mounds were significantly lower than those in one-year mounds.(2)Aboveground biomass demonstrated a significant and consistent increase over time,ultimately reaching a level in perennial mounds that was 5.40 times greater than that in annual mounds.In contrast,both belowground and total biomass exhibited a pattern of an initial decreasfollowed by a recovery.Total biomass peaked in perennial mounds,registering a value 156.51％higher than the minimum observed in two-year-old mounds.The Shannon-Wiener and Simpson diversity indices also showed a unimodal trend,initially increasing and then declining.Both indices reached their maximum values in the second year of succession,exceeding those in the undisturbed flatland control by 15.34％and 5.54％,respectively.(3)The negative correlation between species diversity and productivity(encompassing aboveground,belowground,and total biomass)during succession on zokor mounds was formed through stage-specific processes.It must therefore be understood as a dynamic consequence of the entire successional sequence,not a static relationship at a given stage.(4)Mantel tests and structural equation modeling revealed that both species diversity and productivity were regulated by the stage-specific dynamics of soil bulk density,soil moisture content,organic carbon,and the carbon-to-phosphorus ratio.Specifically,soil organic carbon content accounted for 32.00％of the variation in total biomass.Meanwhile,the soil carbon-to-phosphorus ratio explained 57.00％and 51.00％of the variation in the diversity indices(Shannon-Wiener and Simpson indices)and total biomass,respectively.In summary,during the vegetation succession of plateau zokor mounds,intensified resource competition and reduced spatial heterogeneity led to an increase in community productivity while simultaneously decreasing species diversity.These findings offer a theoretical basis for alpine meadow restoration,biodiversity conservation,and the maintenance of ecosystem functions.