TY - JOUR
T1 - Chronic nitrogen addition induces a cascade of plant community responses with both seasonal and progressive dynamics
AU - Zhou, Xiaobing
AU - Bowker, Matthew A.
AU - Tao, Ye
AU - Wu, Lin
AU - Zhang, Yuanming
N1 - Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/6/1
Y1 - 2018/6/1
N2 - Short-lived herbaceous plants provide a useful model to rapidly reveal how multiple generations of plants in natural plant communities of sensitive desert ecosystems will be affected by N deposition. We monitored dynamic responses of community structure, richness, evenness, density and biomass of herbaceous plants to experimental N addition (2:1 NH4 +:NO3 − added at 0, 0.5, 1, 3, 6 and 24 g N m− 2 a− 1) in three seasons in each of three years in the Gurbantunggut desert, a typical temperate desert of central Asia. We found clear rate-dependent and season-dependent effects of N deposition on each of these variables, in most cases becoming more obvious through time. N addition reduced plant richness, leading to a loss of about half of the species after three generations in the highest N application level. Evenness and density were relatively insensitive to all but the greatest levels of N addition for two generations, but negative effects emerged in the third generation. Biomass, both above and below ground, was non-linearly affected by N deposition. Low and intermediate levels of N deposition often increased biomass, whereas the highest level suppressed biomass. Stimulatory effects of intermediate N addition disappeared in the third generation. All of these responses are strongly interrelated in a cascade of changes. Notably, changes in biomass due to N deposition were mediated by declines in richness and evenness, and other changes in community structure, rather than solely being the direct outcome of release from limitation. The interrelationships between N deposition and the different plant community attributes change not only seasonally, but also progressively change through time. These temporal changes appear to be largely independent of interannual or seasonal climatic conditions.
AB - Short-lived herbaceous plants provide a useful model to rapidly reveal how multiple generations of plants in natural plant communities of sensitive desert ecosystems will be affected by N deposition. We monitored dynamic responses of community structure, richness, evenness, density and biomass of herbaceous plants to experimental N addition (2:1 NH4 +:NO3 − added at 0, 0.5, 1, 3, 6 and 24 g N m− 2 a− 1) in three seasons in each of three years in the Gurbantunggut desert, a typical temperate desert of central Asia. We found clear rate-dependent and season-dependent effects of N deposition on each of these variables, in most cases becoming more obvious through time. N addition reduced plant richness, leading to a loss of about half of the species after three generations in the highest N application level. Evenness and density were relatively insensitive to all but the greatest levels of N addition for two generations, but negative effects emerged in the third generation. Biomass, both above and below ground, was non-linearly affected by N deposition. Low and intermediate levels of N deposition often increased biomass, whereas the highest level suppressed biomass. Stimulatory effects of intermediate N addition disappeared in the third generation. All of these responses are strongly interrelated in a cascade of changes. Notably, changes in biomass due to N deposition were mediated by declines in richness and evenness, and other changes in community structure, rather than solely being the direct outcome of release from limitation. The interrelationships between N deposition and the different plant community attributes change not only seasonally, but also progressively change through time. These temporal changes appear to be largely independent of interannual or seasonal climatic conditions.
KW - Arid
KW - Biodiversity-productivity relationship
KW - Ephemeral plant
KW - Evenness
KW - Global change
KW - Species richness
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U2 - 10.1016/j.scitotenv.2018.01.025
DO - 10.1016/j.scitotenv.2018.01.025
M3 - Article
C2 - 29335179
AN - SCOPUS:85040307265
SN - 0048-9697
VL - 626
SP - 99
EP - 108
JO - Science of the Total Environment
JF - Science of the Total Environment
ER -