Abstract:

Ant nesting affects soil microbial and physicochemical environments and can directly and indirectly regulate the accumulation and regulation of soil organic carbon (SOC) components. The Mellettia leptobotrya community in tropical Xishuangbanna was selected to explore the effects of ant nesting on the accumulation of the SOC pool (i.e., total, easily oxidized, and microbial carbon) and component allocation (easily oxidized organic carbon/total organic carbon and microbial carbon/total organic carbon) in ant nests and reference soils. The effects of ant-induced alterations were examined in terms of the physicochemical properties of component accumulation and allocation of SOC. The results were as follows: 1) ant nesting promoted the accumulation of SOC components (P<0.01). In contrast to the reference soils, the concentrations of total, microbial, and easily oxidized organic carbon in the ant nests increased by 19.7%, 35.5%, and 153.3%, respectively. 2) Ant nesting significantly affected spatiotemporal changes in the soil carbon pool (P<0.050). In contrast to the reference soils, the increased extents of seasonal variations in total organic carbon, easily oxidized organic carbon, and microbial biomass carbon in ant nests were 11.4%-30.1%, 13.6%-72.3%, and 53.4%-212.3%, respectively. Furthermore, these values decreased by 43.1%-422.4% from 0-5 cm to 10-15 cm soil layers in ant nests compared to the reference soils (38.1%-111.4%). 3) The ratios of microbial biomass carbon (15.2%) and easily oxidized organic carbon (36.9%) to total organic carbon were significantly higher in ant nests than in the reference soils (7.5%-31.6%). In the 0-5 cm to 10-15 cm soil layers, the decreased range of microbial biomass carbon (63.1%) was smaller in ant nests than in the reference soils (75.2%), whereas those of easily oxidized organic carbon (277.2%) were higher in ant nests than in reference soils (53.4%). 4) Principal component analysis showed that soil temperature, moisture, pH, and ammonium nitrogen were the main factors controlling soil total organic carbon accumulation, whereas soil temperature and bulk density were the main factors regulating soil active organic carbon allocation. Therefore, the results suggest that ant nesting can regulate soil organic carbon component accumulation and allocation primarily by changing the status of physical soil properties (microclimate, acid-alkalinity, and aeration) and soil nutrients (ammonium nitrogen) in tropical forests.

Key words: ant nesting, active carbon component, carbon accumulation, carbon allocation, Xishuangbanna, Tropical forests

摘要：

蚂蚁筑巢能够通过影响土壤微生物及理化环境而直接或间接调控土壤有机碳各组分积累及分配动态。以西双版纳崖豆藤热带森林群落为研究样地，测定蚁巢和非巢地土壤碳库组分（总有机碳、易氧化有机碳、微生物生物量碳）含量及分配（易氧化有机碳/总有机碳、微生物生物量碳/总有机碳）的时空动态，分析蚂蚁筑巢引起热带森林土壤性质改变对有机碳组分积累与分配的影响特征。结果表明，1）蚂蚁筑巢显著促进土壤总有机碳及各组分含量的积累（P<0.01）。相较于非巢地，蚁巢土壤总有机碳、微生物生物量碳、易氧化有机碳含量分别提高了19.7%、35.4%和153.3%。2）蚂蚁筑巢显著影响土壤碳库各组分含量的时空变化（P<0.050）。其中，相较于非蚁巢，蚁巢土壤总有机碳、易氧化有机碳、微生物生物量碳含量季节变化的增幅分别为11.4%-30.1%、13.6%-72.3%、53.4%-212.2%；蚁巢土壤总有机碳、微生物生物量碳、易氧化有机碳含量沿土层降幅（43.1%-422.4%）显著高于非蚁巢（38.1%-111.4%）。3）蚁巢土壤微生物生物量碳（15.2%）和易氧化有机碳（36.9%）在总有机碳中分配均值均显著高于非巢地（7.5%-31.6%），蚁巢土壤微生物生物量碳分配沿土层降幅（63.1%）小于非蚁巢（75.2%），易氧化有机碳分配（277.2%）则大于非蚁巢（53.4%）。4）主成分分析表明，温湿度、pH、氨氮是调控蚁巢土壤有机碳组分积累的主要协同因子，温度和容重是蚁巢土壤有机碳组分分配的主控因子。蚂蚁筑巢主要通过改变土壤物理环境（微气候、酸碱性、通气性）和土壤氮库（铵氮）的状况，进而对土壤有机碳组分积累及组分分配产生重要影响。

关键词: 蚂蚁筑巢, 活性碳组分, 碳积累, 碳分配, 西双版纳, 热带森林