Precipitation reduction alters herbaceous community structure and composition in a savanna

Abstract

Questions In the changing climate scenario, the decline in precipitation is expected to alter water availability for plants, which in turn affects plant community structure and composition. The responses of community composition and structure to declines in precipitation are well documented in other biomes but remain understudied in water‐limited savannas. Location A savanna ecosystem in southwest China. Methods We used a four‐year (2014–2017) precipitation manipulation experiment to examine changes in herbaceous community composition and structure across the species, functional group and community levels under precipitation reduction. Results Precipitation reduction significantly decreased the average height and percentage cover of the herbaceous community, while increasing species richness and the Pielou evenness index. Precipitation reduction significantly decreased average height, percentage cover and relative abundance of graminoids and perennials, but increased those of forbs and annuals. Precipitation reduction prompted a shift in the dominant species of the herbaceous community towards Fimbristylis monostachya. Conclusions The results show that precipitation reduction changed the composition and structure of the herbaceous community of this savanna. Furthermore, they provide strong evidence that changes in herbaceous community structure and composition in response to the intensity and duration of precipitation reduction in this savanna exhibited relatively low thresholds, which suggests that the herbaceous community's response to a decline in precipitation was essentially nonlinear. These findings imply that even relatively small declines in precipitation may stimulate shifts in plant community structure and composition and affect the function and stability of savanna ecosystems.

Weed Responses to Crop Residues Management in a Summer Maize Cropland in the North China Plain

“…This result could be attributed to the fact that annual weeds may be rapid growth species with a short life span, growing and reproducing faster than perennials when encountering disadvantageous conditions like drought [35]. Overall, the present study found contrasting results of the relative abundance of weed types under different crop residues management, indicating that different weed types may have different adaptation strategies associated with their morphological or physiological traits to adapt to environmental changes [36].…”

The response of litter decomposition to extreme drought modified by plant species, plant part, and soil depth in a temperate grassland

“…Numerous studies in grasslands documented shifts in plant species abundances in response to natural or experimental drought (Albertson & Weaver, 1942; Breman & Cissé, 1977; Gibbens & Beck, 1987; Hoover et al, 2014; Jin et al, 2019), either by reordering of species or functional groups (i.e., some species become abundant under changing conditions at the expense of others; Smith et al, 2009), or through the replacement of a dominant species. When a shift in species abundances occurs, the litter decomposition rate of species that are favored under altered environmental conditions may differ from that of previously abundant species.…”

Extinction risk of Chinese angiosperms varies between woody and herbaceous species

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