title: Heterotrophic respiration does not acclimate to continuous warming in a subtropical forest.
abstract: As heterotrophic respiration (R(H)) has great potential to increase atmospheric CO2 concentrations, it is important to understand warming effects on R(H) for a better prediction of carbon-climate feedbacks. However, it remains unclear how R(H) responds to warming in subtropical forests. Here, we carried out trenching alone and trenching with warming treatments to test the climate warming effect on R(H) in a subtropical forest in southwestern China. During the measurement period, warming increased annual soil temperature by 2.1 °C, and increased annual mean R(H) by 22.9%. Warming effect on soil temperature (WE(T)) showed very similar pattern with warming effect on R(H) (WE(RH)), decreasing yearly. Regression analyses suggest that WE(RH) was controlled by WE(T) and also regulated by the soil water content. These results showed that the decrease of WE(RH) was not caused by acclimation to the warmer temperature, but was instead due to decrease of WE(T). We therefore suggest that global warming will accelerate soil carbon efflux to the atmosphere, regulated by the change in soil water content in subtropical forests.
authors.affiliation: Key laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China.|Ailaoshan Station for Subtropical Forest Ecosystem Studies, Jingdong, 676209, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Chuansheng
authors.initials: C
authors.lastname: Wu
authors.affiliation: Global Carbon Cycle Research Section, Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, 305-8506, Japan.
authors.forename: Naishen
authors.initials: N
authors.lastname: Liang
authors.affiliation: Key laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China.|Ailaoshan Station for Subtropical Forest Ecosystem Studies, Jingdong, 676209, China.
authors.forename: Liqing
authors.initials: L
authors.lastname: Sha
authors.affiliation: Key laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Xingliang
authors.initials: X
authors.lastname: Xu
authors.affiliation: Key laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China.|Ailaoshan Station for Subtropical Forest Ecosystem Studies, Jingdong, 676209, China.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Huazheng
authors.initials: H
authors.lastname: Lu
authors.affiliation: Key laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Song
authors.affiliation: Key laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China.
authors.forename: Qinghai
authors.initials: Q
authors.lastname: Song
authors.affiliation: Jingdong Bureau of National Nature Reserve, Jingdong, Yunnan 676209, China.
authors.forename: Youneng
authors.initials: Y
authors.lastname: Xie