植食性土壤动物对我国东部典型森林细根生产量的影响OA

As a key component of carbon cycling in terrestrial ecosystems,the production of fine roots is regulated by both environmental and biological factors.Herbivorous soil animals are an important factor influencing fine root turnover.To elucidate the mechanisms by which herbivorous soil animals influence fine root production across broad geographical gradients,we established 17 plots in natural secondary forests spanning a latitudinal range of 18°36′N-53°26′N in eastern China.We manipulated herbivorous soil animal activity by applying insecticides to control their feeding on roots.Following one-year treatment,fine roots were collected from the 0-20 cm soil layer,classified using the root order classification approach,and their production was quantified to examine differential responses of absorptive fine root(AFR)and transport fine root(TFR)yields to herbivory disturbance.The results showed that:(1)under natural conditions,both AFR and TFR production exhibited a significant increasing trend from north to south sites,with yields in tropical and subtropical regions being significantly higher than those in temperate and cold-temperate regions.Specifically,AFR production in tropical forests was 1.5-2.1 times of that in cold-temperate plots(78-94 g·m-2),and TFR production was 3-4 times of that in cold-temperate plots(138-150 g·m-2).Some mid-subtropical plots had lower yields than adjacent areas in the same climatic zone due to micro-environmen-tal differences.(2)After excluding herbivorous soil animals,AFR and TFR production significantly increased in half of the plots,but the magnitude of response differed significantly across latitude zones.AFR production in-creased by 20％-25％and TFR production by 25％-30％in low-latitude tropical and subtropical regions,with AFR yields in some subtropical plots being the highest among adjacent latitudes after treatment.AFR production in-creased by only 10％-15％in high-latitude cold-temperate to temperate regions,with cold-temperate plots becom-ing low-yield areas and showing no significant geographical gradient.Two-way ANOVA Showed that there was a sig-nificant interaction between treatment effects and latitude zones(P＜0.05),with a stronger regulatory effect of soil animals on fine root production in low-latitude regions.(3)Fine root production was highly significantly negatively correlated with latitude and significantly positively correlated with mean annual temperature and annual precipitati-on,confirming that hydrothermal condition is the fundamental driver of geographical differentiation of fine root pro-duction.The regulatory effect of herbivorous soil animals showed latitudinal dependency.Low-latitude regions in-duced plant compensatory growth through feeding pressure,while high-latitude low-temperature environments inhib-ited soil animal activity,masking their effects by climatic factors.This study provides an important reference for fur-ther exploring the relationship between herbivorous soil animals and fine root production in forests,and has impor-tant theoretical significance for understanding the relationship between energy flow and material cycling in forest e-cosystems.