Termites are primary ecosystem engineers that play vital roles in tropical and subtropical ecosystems. Termite mounds play a central role in nutrient fixation and cycling in terrestrial ecosystems. However, termite-microbe interactions and their impact on nutrient cycling processes in tropical ecosystems have been less studied.
In a study published in Geoderma, researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences investigated termite-induced changes in soil microbial communities and their nutrient cycling functions within termite mounds (i.e., live mounds and abandoned mounds) in the humid tropical region of southwest China.
The researchers examined the spatial distribution of microbial communities and their related functions on nutrient cycling in different mound stages (live mounds and abandoned mounds). They demonstrated the changes in the spatial distribution pattern of microbial community composition and structure in the termite mounds.
The results showed that live termite mounds harbor unique microbial communities with an intermediate abundance between surrounding topsoils and deep soils and a higher ratio of fungi to bacteria in live mounds relative to surrounding soils. However, the microbial communities tended to resemble surrounding soils when the mounds were abandoned.
In live mounds, the microbial communities decreased significantly compared to the surrounding surface soils. Conversely, the termite mounds supported higher microbial richness and biomass than the surrounding deep soils. The elevated nutrients in the mounds may provide more energy and primary carbon sources for the growth of microorganisms, resulting in a greater increase in the microbial communities in live mounds than in surrounding deep soils.
Microbes in the live mounds tended to use complex, residual organic substrates as their energy source rather than plant-derived organic matter. However, when the mounds were abandoned, the microbes acquired energy identical to the pre-existing recalcitrant C of mounds and easily degradable organic materials from plant sources.
"Our results demonstrate that termite nesting behaviour and its effect on the physicochemical properties shape the microbial communities and microbial processes in termite mounds and subsequently contribute to soil nutrient cycling in tropical ecosystems," said LIU Wenjie of XTBG.
