Synchronous Responses of Plant Functional Traits to Nitrogen Deposition From Dominant Species to Functional Groups and Whole Communities in Alpine Grasslands on the Qinghai-Tibetan Plateau

Abstract

Nitrogen deposition is recognized as one of the major threats to the ecosystem function of alpine grasslands on the Qinghai-Tibetan Plateau (QTP). However, few studies have documented the gradient responses of plant species, functional groups, and communities in alpine grassland ecosystems to various levels of N deposition on the QTP. We applied eight linear mixed-effect models combing acidification, eutrophication, and phosphorus availability to explore if the responses of functional traits (particularly plant height and specific leaf area) of plants from dominant species to functional groups and whole communities in different types of grassland to nitrogen deposition were consistent with the same or different models. We found that the specific leaf area of Stipa capillata, non-forb, and community-weighted mean value in the alpine steppe were synchronous and related to acidification with nitrogen addition; the height of Stipa capillata, non-forb, and community-weighted mean value in the alpine steppe was synchronous and related to acidification, eutrophication, and phosphorus availability with nitrogen addition; the height and specific leaf area of Elymus breviaristatus to functional groups and community-weighted mean value in cultivated grasslands (CGs) were synchronous and related to acidification, eutrophication, and phosphorus availability with nitrogen addition. Most of the responses of functional traits of plants to acidification, eutrophication, and phosphorus availability associated with nitrogen deposition in the alpine steppe and the CG were synchronous, while only the response of the specific leaf area of forb functional groups to eutrophication associated with N deposition in the alpine steppe was asynchronous.

Divergent coupling mechanism of precipitation on plant community multifunction across alpine grassland on the Tibetan Plateau

“…Apparently, the balance among C, N, and P exerted a profound impact on diverse plant functions, which was able to quickly respond to the dynamics of nutrient supply via its physiological adaptability. Previous studies have explored the coupling patterns of plant N and P (Zhou et al, 2020), leaf N and P (Li et al, 2022), and root N and P in alpine grassland (Ma et al, 2020). And they have illustrated that water and heat play a crucial effect in determining the coupling and decoupling process of C, N, and P biogeochemical cycles.…”

Nitrogen Addition Affects Ecosystem Carbon Exchange by Regulating Plant Community Assembly and Altering Soil Properties in an Alpine Meadow on the Qinghai–Tibetan Plateau

“…A study from the QTP found that the N deposition could shift plant species composition in favor of graminoids ( Shen H. et al, 2022 ). The responses of the functional traits of alpine plants to the N deposition showed cascading effects from dominant species to functional groups and plant communities ( Li et al, 2022 ). A long-term N addition can greatly reduce species richness ( Li S. et al, 2019 ), and NEE may increase under N addition ( Niu et al, 2009 , 2010 ).…”

Editorial: Patterns, functions, and processes of alpine grassland ecosystems under global change

“…In alpine meadow, N and P addition significantly affect t plant communities ( Ma et al., 2021 ), soil microbial community and enzyme activities ( Zi et al., 2022 ), and microbial functional genes ( Xiao et al., 2022 ). In alpine steppe, N and P application led to an increase in aboveground biomass ( Li et al., 2021b ), and increased intensity of bacteria and fungi ( Li et al., 2021c ), also affected the plant functional traits ( Li et al., 2022d ). Meanwhile, grazing increased herbage respiration in summer, presumably through stimulation of gross photosynthesis ( Yuan et al., 2022 ), and changed plant community composition and reduced stochasticity of soil microbial community assembly of alpine grasslands ( Li et al., 2022a ).…”