title: Effects of simulated acid rain on soil fauna community composition and their ecological niches.
abstract: Acid rain is one of the severest environmental issues globally. Relative to other global changes (e.g., warming, elevated atmospheric [CO2], and nitrogen deposition), however, acid rain has received less attention than its due. Soil fauna play important roles in multiple ecological processes, but how soil fauna community responds to acid rain remains less studied. This microcosm experiment was conducted using latosol with simulated acid rain (SAR) manipulations to observe potential changes in soil fauna community under acid rain stress. Four pH levels, i.e., pH 2.5, 3.5, 4.5, and 5.5, and a neutral control of pH 7.0 were set according to the current pH condition and acidification trend of precipitation in southern China. As expected, we observed that the SAR treatments induced changes in soil fauna community composition and their ecological niches in the tested soil; the treatment effects tended to increase as acidity increased. This could be attributable to the environmental stresses (such as acidity, porosity and oxygen supply) induced by the SAR treatments. In addition to direct acidity effect, we propose that potential changes in permeability and movability of water and oxygen in soils induced by acid rain could also give rise to the observed shifts in soil fauna community composition. These are most likely indirect pathways of acid rain to affect belowground community. Moreover, we found that nematodes, the dominating soil fauna group in this study, moved downwards to mitigate the stress of acid rain. This is probably detrimental to soil fauna in the long term, due to the relatively severer soil conditions in the deep than surface soil layer. Our results suggest that acid rain could change soil fauna community and the vertical distribution of soil fauna groups, consequently changing the underground ecosystem functions such as organic matter decomposition and greenhouse gas emissions.
authors.affiliation: Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China; Key Laboratory of Tropical Agro-Environment, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China; Guangdong Engineering Research Center for Modern Eco-agriculture and Circular Agriculture, Guangzhou 510642, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wei
authors.affiliation: Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China; Key Laboratory of Tropical Agro-Environment, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China; Guangdong Engineering Research Center for Modern Eco-agriculture and Circular Agriculture, Guangzhou 510642, China. Electronic address: jeanzh@scau.edu.cn.
authors.forename: Jiaen
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China; Key Laboratory of Tropical Agro-Environment, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China; Guangdong Engineering Research Center for Modern Eco-agriculture and Circular Agriculture, Guangzhou 510642, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Qin
mesh_terms: D015258:Acid Rain / Q000633:toxicity*; D000818:Animals; D002681:China; D004463:Ecology; D017753:Ecosystem; D007448:Invertebrates / Q000187:drug effects / Q000502:physiology*; D009584:Nitrogen; D011891:Rain; D012987:Soil / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D015258:Acid Rain; D012987:Soil; D014874:Water Pollutants, Chemical; D009584:Nitrogen
keywords: Acidic red soil; Below-ground ecosystems; Global changes; Soil animals; Subtropical ecosystems