ABSTRACT
Elucidating mechanisms underlying community assembly and biodiversity patterns is central to ecology and evolution. Genome size (GS) has long been hypothesized to potentially affect species' capacity to tolerate environmental stress and might therefore help drive community assembly. However, its role in driving ß-diversity (i.e., spatial variability in species composition) remains unclear. We measured GS for 161 plant species and community composition across 52 sites spanning a 3200-km transect in the temperate grasslands of China. By correlating the turnover of species composition with environmental dissimilarity, we found that resource filtering (i.e., environmental dissimilarity that includes precipitation, and soil nitrogen and phosphorus concentrations) affected ß-diversity patterns of large-GS species more than small-GS species. By contrast, geographical distance explained more variation of ß-diversity for small-GS than for large-GS species. In a 10-year experiment manipulating levels of water, nitrogen, and phosphorus, adding resources increased plant biomass in species with large GS, suggesting that large-GS species are more sensitive to the changes in resource availability. These findings highlight the role of GS in driving community assembly and predicting species responses to global change.
Subject(s)
Biodiversity , Grassland , Plants , Soil , Nitrogen , PhosphorusABSTRACT
Plant genome size (GS) varies greatly over 2400-fold in angiosperms. Genome sizes are closely related to plant traits from cellular to individual level, which would have far-reaching ecolo-gical implications. Genome size may shape the interspecific responses of plants to changes of resource availability in Inner Mongolia grassland which is co-limited by water and nitrogen availabi-lity. We tested the role of genome size in structuring plant community composition after single and combined water (W) amd nitrogen (N) addition in a typical grassland of Inner Mongolia. Plant genome sizes were estimated by flow cytometry. We found that the response of plant aboveground net primary production (ANPP) to change in water availability was significantly affected by genome size. Water and NW addition significantly increased ANPP of small GS plants, instead of large GS species. Nitrogen addition had no effects on ANPP of both small and large GS plants. We found no effects of all the treatments on plant species richness. Results showed that GS modulated the response of grassland plant species to changes in water rather than nitrogen availability in Inner Mongolia. Since GS is a relatively constant trait with substantial interspecific variation, the application of GS in ecological studies would be of great significance to better understanding of ecosystem structure and function under global change.
