pH drives ammonia oxidizing bacteria rather than archaea thereby stimulate nitrification under Ageratina adenophora colonization
HaifengXiao, Douglas A.Schaefer. Xiaodong Yang
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China.
Understanding mechanisms of successful colonization by exotic plant species in non-native habitat is critical to meet long-term restoration aims. Overgrowing plants can alter resources, especially soil inorganic nitrogen availability and get benefits from positive feedback. However, comprehensive knowledge on particular mechanisms underlying their successful colonization remains unclear. Here, field examinations and laboratory manipulations were combined to investigate significant impact of overgrowing Ageratina adenophora on soil NO3−-N availability and nitrification. Interestingly, we found significant enhancement in soil total N, NO3−-N, pH, potential nitrification rates, and ammonia oxidizing bacteria (AOB), while reduced abundance of ammonia oxidizing archaea (AOA) under the influence of A. adenophora. Notably, AOB abundance was positively correlated with both pH and soil potential nitrification rates. AOA abundance was negatively correlated with pH and had no significant correlation with soil nitrification potential. Both AOA and AOB communities significantly differed between populated and non-populated soils. pH was the strongest factor contributing to this community difference. We conclude that A. adenophora stimulates nitrification with the help of AOB rather than AOA under relatively higher soil pH condition.
Keywords: Ageratina adenophora, Nitrification, Soil pH, Ammonia oxidizing bacteria, Ammonia oxidizing archaea.