Role of desert annuals in nutrient flow in arid area of Northwestern China: a nutrient reservoir and provider |
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Authors: | Bao-Ming Chen Gen-Xuan Wang Shao-Lin Peng |
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Institution: | (1) State Key Laboratory of Biocontrol, School of Life Science, Sun Yat-Sen (Zhongshan) University, Guangzhou, 510275, Guangdong Province, People’s Republic of China;(2) College of Life Science, Zhejiang University, Hangzhou, 310027, People’s Republic of China |
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Abstract: | Previous studies have tested the “vernal dam” hypothesis of spring ephemeral herbs in hardwood forests. The desert annual
is a component of the desert ecosystem that takes advantage of water resources and temperature conditions during the rainy
season to rapidly complete its life cycle within several months. To understand the role desert annual/ephemeral plants play
in nutrient flow, we studied vegetation cover, nitrogen content and litter production of annual plants and litter decomposition
rate in plant communities dominated by four shrubs (Haloxlon ammodendron, Hedysarum scoparium, Calligonum mongolicum, and Nitraria tangutorum) and two dominant annuals (Agriophyllum squarrosum and Halogeton arachnoideus Moq) in Minqin, northwestern China. Results indicate that over half of the total vegetation cover was provided by annuals.
Annuals also took up a large amount of nitrogen (0.46–3.78 g N m−2) along the oasis–desert ecotone. Litter production and nutrient content were higher in areas dominated by annual plants than
in areas dominated by shrubs. Furthermore, the litter decomposition rate of the annuals was higher than that of the shrubs,
except for the shrub H. ammodendron, although almost all of the litter’s carbon (C) and nitrogen (N) remained after 6 months of decomposition. Without the annuals,
more nutrients and rainwater might be lost through leaching or dust transfer caused by the wind erosion. In addition, green
twigs of the annuals are the food for some animals, we found some green twigs and litter from annuals left in front of gerbil
and rabbit burrows, sometimes even blocking these burrows. Thus, desert summer annuals, like nutrient reservoirs and providers,
take up nutrients during the rainy season, providing some animals and microbes with food, and finally release these nutrients
after death.
Bao-Ming Chen and Gen-Xuan Wang contributed equally to this work. |
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Keywords: | Annual plant Ephemeral Nitrogen Nutrient Vernal dam |
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