Soil respiration, sometimes called total soil respiration (RT), represents the second largest CO2 flux from soil to atmosphere in the terrestrial ecosystems. It involves the microbial respiration of litter from aboveground sources, belowground litter and root respiration, from rhizodeposition. The unexpected heavy snowfall events in subtropical forest areas represent climate change anomalies that lead to increased sensitivity to RT and its fractions.
In a study published in Applied Soil Ecology, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) investigated how aboveground litterfall respiration and its environmental parameters respond to heavy snowfall events.
The researchers set up a chamber with automated CO2 efflux in the subtropical forests of the Ailao Mountain. They carried out two treatments: a control treatment with litterfall to measure the total soil respiration (RT) and a litter removal treatment to measure aboveground litterfall respiration (RL). They examined the he responses of aboveground litterfall respiration to unexpected heavy snowfall events and soil temperature, soil moisture, rainfall, total litterfall, litter water content, nitrate nitrogen, and ammonium nitrogen.
They found that the aboveground litterfall respiration had strong connection with soil temperature, soil moisture, rainfall and litter water content for two periods: before the heavy snowfall event (BS) and during and after the heavy snowfall event (AS). However, it was not significantly connected with ammonium nitrogen for either period.
Furthermore, they found that the unexpected snowfall events took effects the connection between aboveground litterfall respiration and total litterfall. The snowfall events declined temperature sensitivity of aboveground litterfall respiration.
“The results indicate that current global terrestrial models underestimate aboveground litterfall respiration trends for the feedback of global climate change in subtropical forests,” said ZHANG Yiping of XTBG.
ZHANG Yiping Ph.D
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China