Competition between plants and soil microbes for available nitrogen as well as mechanisms responsible for coexistence of dominant plant species in terrestrial ecosystems have been hot topics in ecological studies.

Supported by the National Natural Science Foundation of China and the National Basic Research Program of China, Dr. XU Xingliang from Institute of Geographic Sciences and Natural Resources Research (IGSNRR) with his colleagues investigated spatio-temporal patterns of competition between plants and soil microbes for available nitrogen in alpine meadows using short-term 15N tracer experiment. The results showed that competition between plants and soil microbes for available nitrogen in alpine meadows were depended on root density and therefore soil depth, inorganic N form, and different periods during the growing season.

Meanwhile, using 15N tracers they investigated how dominant plant species acclimate to nutrient enrichment caused by saprophyte fungi in alpine meadows. It was shown that most of targeted plant species exhibited chemical niche shifts instead of niche conservatism. This indicates that chemical niche shifts can occur rapidly in alpine meadows, and challenges the core of niche-based geographical models which have employed niche conservatism as an important assumption.

These results have been published in Journal of Ecology 99, 563-571 and Plant and Soil 341, 495-504.

References:

Xu, X.L., Ouyang, H., Richter, A., Wanek, W., Cao, G.M. and Kuzyakov, Y. (2011): Spatio-temporal variations determine plant–microbe competition for inorganic nitrogen in an alpine meadow. Jounal of Ecology 99, 563−571.

Xu, X.L., Ouyang, H., Cao, G.M., Richter, A., Wanek, W. and Kuzyakov, Y. (2011): Dominant plant species shift their nitrogen uptake patterns in response to nutrient enrichment caused by a fungal fairy in an alpine meadow. Plant and Soil 341, 495-504.