[Responses of soil microbial community structure and function to simulated warming in alpine forest.]

Area of Science:

• Ecology
• Soil Science
• Microbiology

Background:

• Alpine ecosystems are sensitive to climate change.
• Soil microbial communities are crucial for ecosystem function.
• Understanding microbial responses to warming is vital for predicting ecosystem changes.

Purpose of the Study:

• To investigate the effects of simulated warming on soil microbial community structure and soil enzyme activity in an alpine coniferous forest.
• To differentiate the responses of bacteria and fungi to elevated temperatures.

Main Methods:

• Soil cores from organic and mineral layers were incubated under controlled conditions.
• Three temperature treatments were applied: ambient, ambient + 2°C, and ambient + 4°C.
• Phospholipid fatty acids (PLFAs) were analyzed to assess microbial community structure and enzyme activities were measured.

Main Results:

• Warming significantly reduced bacterial PLFAs in the organic layer and Gram-negative bacteria (G⁻) PLFAs in the mineral layer.
• Soil fungi were less affected by warming, and the ratio of Gram-positive (G⁺) to Gram-negative (G⁻) bacteria increased.
• No significant changes in soil enzyme activities (laccase, BG, AP, NAG) were observed under warming conditions.
• Positive correlations between fungal, bacterial, G⁺, and G⁻ PLFAs indicated coordinated microbial growth, while a negative correlation between BG and bacteria suggested carbon source competition.

Conclusions:

• Soil bacteria are more sensitive to warming than fungi in alpine forest soils.
• Fungal communities exhibit greater tolerance to elevated temperatures.
• Warming alters soil microbial community structure, but soil enzyme activities remain stable under the studied conditions.