蚂蚁筑巢对西双版纳热带森林土壤易氧化有机碳时空动态的影响

蚂蚁筑巢定居能够形成与巢穴周围显著不同的微生境和土壤养分环境,从而对土壤易氧化有机碳(EOC)产生重要影响.本研究以中国科学院西双版纳勐仑热带植物园白背桐群落为研究对象,比较蚂蚁巢地与非巢地土壤EOC时空分布特征,并分析蚂蚁筑巢引起土壤理化性质的改变对土壤EOC时空动态的影响.结果表明: 研究区蚁巢和非蚁巢地土壤EOC随月份均呈明显的单峰型变化规律,表现为6月>9月>3月>12月;土壤EOC沿土层呈逐渐降低的变化趋势,在0～5 cm土层,蚁巢土壤EOC显著大于非巢地,在5～10和10～15 cm土层的差异不显著.蚂蚁筑巢显著提高了土壤温度、土壤有机碳、土壤易氧化有机碳、土壤微生物生物量碳、全氮、硝态氮和水解氮含量,显著降低了土壤含水率和容重,但对铵态氮、pH值的影响不显著.土壤有机碳、土壤微生物生物量碳是调控蚁巢和非巢地土壤EOC时空变化的主要因子,土壤温度、含水率、全氮和硝态氮等土壤指标对土壤EOC的影响次之.蚂蚁筑巢主要通过改变微生境(土壤温度和水分)及土壤养分(主要是土壤有机碳和微生物生物量碳)的状况,进而调控热带森林土壤易氧化有机碳的时空动态.

Effects of ant nesting on the spatiotemporal dynamics of soil easily oxidized organic carbon in Xishuangbanna tropical forests,China.

Ant nesting can form microhabitat and soil nutrient condition in their nests that is diffe-rent from the surrounding environment, thus having a crucial effect on the variation of soil easily oxidized organic carbon (EOC). In this study, the Mallotus paniculatus communities in Menglun Tropical Botanical Garden of Xishuangbanna, Chinese Academy of Sciences was taken as the research object. We compared the spatiotemporal distribution of soil EOC in ant nests and the refe-rence soils, and analyzed the relationship of the variation in soil EOC to the changes in soil physicochemical properties. The results showed that soil EOC in ant nests and the reference soils had a unimodal change trend with months. The order was ranked as June>September>March>December. The soil EOC decreased with the soil layers. The EOC was higher in 0-5 cm nest soils than in the refe-rence soils, while it was not significantly different in the 5-10 cm and 10-15 cm soil layers. Ant nesting increased soil temperature, soil organic carbon, soil easily oxidized organic carbon, soil microbial biomass carbon, total nitrogen, soil nitrate nitrogen and hydrolysis nitrogen, but reduced the soil water content and bulk density. The impacts of ant nesting on soil ammonium and pH was not significant. The soil organic carbon and microbial biomass carbon had crucial roles in regulating the spatiotemporal variation in EOC in ant nests and the reference soils, whereas the effects of soil temperature, soil water content, total nitrogen and nitrate nitrogen ranked the second. The ant nesting had a crucial effect on the spatiotemporal variations in easily oxidized organic carbon, mainly through changing the microhabitat (e.g., soil temperature and moisture) and soil nutrients (e.g., soil organic carbon and microbial biomass carbon) in Xishuangbanna tropical forests.