Grassland ecosystems cover c. 40% of global land area and contain c. 40% of soil organic carbon. Understanding the effects of adding nutrients to grasslands is essential because they provide much of our food, support diverse ecosystem services and harbor rich biodiversity. Using the meadow steppe (grassland) study site of Inner Mongolia, we manipulated seven key nutrients and a cocktail of micronutrients to examine their effects on grassland biomass productivity and diversity. The results, explained in structural equation models, link two previously disparate hypotheses in grassland ecology: (1) the light asymmetry competition hypothesis and (2) the genome size-nutrient interaction hypothesis. We show that aboveground net primary productivity increases predominantly from species with large genome sizes with the addition of nitrogen, and nitrogen plus phosphorus. This drives an asymmetric competition for light, causing a decline in species richness mainly in species with small genome sizes. This dynamic is likely to be caused by the nutrient demands of the nucleus and/or the scaling effects of nuclear size on cell size which impact water use efficiency. The model will help inform the best management approaches to reverse the rapid and unprecedented degradation of grasslands globally.
|Original language||English (US)|
|Number of pages||12|
|State||Published - Dec 2022|
Bibliographical noteFunding Information:
The authors acknowledge the staff of Erguna Forest‐Steppe Ecotone Research Station for their support. The authors are grateful to Dashuan Tian, Haiyang Zhang, Xiaoguang Wang, Guojiao Yang, Liangchao Jiang, Lingyu Shao and Mengzhen Xu for their help during the course of the experiments and writing. This study was supported by grants from the National Natural Science Foundation of China (42130515) and the Chinese National Key Development Program for Basic Research (2017YFA0604802).
© 2022 The Authors. New Phytologist © 2022 New Phytologist Foundation.
- Inner Mongolia Steppe
- genome size
- light competition
- multiple nutrient manipulations
- net primary productivity
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't