Characteristics and controls of ecological stoichiometry of shrub leaf in the alpine region of northwest China.

• Shrub growth is limited by N but increase leaf C to resist harsh conditions. • Stoichiometric ratios of plants were not related to those of soils, but controlled by soil properties. • Soil water, bulk density and porosity drive the ecological stoichiometry. Studying the ecological stoichiometry of ecosystem would promote understanding about how plant adapt to environment changes. As a typical alpine region, the Qilian Mountain of northwest China is a good platform for this purpose, but the ecological stoichiometric of plants is largely unknown. This study selected five dominant shrub species to collect shrub leaves and soils to explored the carbon (C): nitrogen (N): and phosphorus (P) characteristics and controls of them. The mean content of C (549.39 g kg−1) in leaves of shrub plants was higher than that of global flora. N:P ratio of five shrubs leaves (7–10) were all lower than 14. The shrubs in the alpine regions resist harsh conditions by increasing leaf C content, and their growth is restricted by N. Compared with altitude and soil, shrub species have greater effects on soil stoichiometric characteristics. The Caragana tangutica shrub may be the best specie for ecological restoration. The stoichiometric ratios of shrub leaves are not related to those of soils, but controlled by soil properties, mainly including soil water content (34.2%), bulk density (32.5%) and total porosity (12.8%). This study interpreted the mechanism how shrub adapt to changing environment, and provide information for how effectively restore the ecological environment in the alpine regions. [ABSTRACT FROM AUTHOR]