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Hierarchy of the factors influencing the broad-scale waterbirds functional diversity gradients in temperate China
  • +4
  • Yamian Zhang,
  • Wenzhuo Tan,
  • Li Wen,
  • QIng Zeng,
  • Haitao Tian,
  • Yifei Jia,
  • Guangchun Lei
Yamian Zhang
Beijing Forestry University
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Wenzhuo Tan
Beijing Forestry University
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Li Wen
NSW Department of Planning Industry and Environment
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QIng Zeng
Beijing Forestry University
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Haitao Tian
Beijing Forestry University
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Yifei Jia
Beijing Forestry University
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Guangchun Lei
Beijing Forestry University
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Abstract

Geographical gradients in species diversity have long fascinated biogeographers and ecologists. However, the extent and generality of the positive/negative effects of the important factors governing functional diversity (FD) patterns are still debated, especially for the freshwater domain. We examined lake productivity and functional richness (FRic) of waterbirds sampled from 35 lakes and reservoirs in northern China with a geographic coverage of over 5 million km2. We used structural equation modelling (SEM) to explore the causal relationships between geographic position, climate, lake productivity and waterbirds FRic. We found unambiguous altitudinal and longitudinal gradients in lake productivity and waterbirds FD, which were strongly mediated by local environmental factors. Specifically, we found 1) lake productivity increased northeast but decreased with altitude, and the observed gradients were driven by climate and nutrient availability, with 93% of variation explained in the individual SEM; 2) waterbirds FD showed similar geographic and elevational gradients.; the environmental factors which had direct and/or indirect effects on these geographic and elevational gradients included climate, lake productivity and morphology, which collectively explained more than 56% of the variation in waterbirds FD; and 3) a significant (P = 0.029) causality between lake productivity and waterbirds FD was confirmed. Nevertheless, the causality link was relatively weak in comparison with climate and lake area (standardized path coefficient was 0.65, 0.21, and 0.17 for climate, area, and productivity, respectively). Through articulating the dominant causality paths, our results could contribute to the mechanistic explanations underlying the observed broad–scale biodiversity gradients.

Peer review status:ACCEPTED

15 May 2020Submitted to Ecology and Evolution
17 May 2020Submission Checks Completed
17 May 2020Assigned to Editor
19 May 2020Reviewer(s) Assigned
06 Jun 2020Review(s) Completed, Editorial Evaluation Pending
18 Jun 2020Editorial Decision: Revise Minor
14 Aug 20201st Revision Received
14 Aug 2020Review(s) Completed, Editorial Evaluation Pending
14 Aug 2020Submission Checks Completed
14 Aug 2020Assigned to Editor
20 Aug 2020Editorial Decision: Accept