title: Rapid plant species loss at high rates and at low frequency of N addition in temperate steppe.
abstract: Humans are both intentionally (fertilization) and unintentionally (atmospheric nutrient deposition) adding nutrients worldwide. Increasing availability of biologically reactive nitrogen (N) is one of the major drivers of plant species loss. It remains unclear, however, whether plant diversity will be equally reduced by inputs of reactive N coming from either small and frequent N deposition events or large and infrequent N fertilization events. By independently manipulating the rate and frequency of reactive N inputs, our study teases apart these potentially contrasting effects. Plant species richness decreased more quickly at high rates and at low frequency of N addition, which suggests that previous fertilization studies have likely over-estimated the effects of N deposition on plant species loss. N-induced species loss resulted from both acidification and ammonium toxicity. Further study of small and frequent N additions will be necessary to project future rates of plant species loss under increasing aerial N deposition.
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China; State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China; University of Chinese Academy of Sciences, Yuquan Road, Beijing, 100049, China.
authors.forename: Yunhai
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaotao
authors.initials: X
authors.lastname: Lü
authors.forename: Forest
authors.initials: F
authors.lastname: Isbell
authors.forename: Carly
authors.initials: C
authors.lastname: Stevens
authors.forename: Xu
authors.initials: X
authors.lastname: Han
authors.forename: Nianpeng
authors.initials: N
authors.lastname: He
authors.forename: Guangming
authors.initials: G
authors.lastname: Zhang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yu
authors.forename: Jianhui
authors.initials: J
authors.lastname: Huang
authors.forename: Xingguo
authors.initials: X
authors.lastname: Han
mesh_terms: D044822:Biodiversity; D002681:China; D004305:Dose-Response Relationship, Drug; D005308:Fertilizers / Q000032:analysis*; D065948:Grassland; D009584:Nitrogen / Q000494:pharmacology*; D057948:Viridiplantae / Q000187:drug effects / Q000502:physiology*
chemical_list: D005308:Fertilizers; D009584:Nitrogen
keywords: Inner Mongolia; N addition frequency; acidification; ammonium toxicity; biodiversity; peak effect; pulse effect; temperate grassland