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A mismatch between community assembly and abundance-based diversity indices
  • Matthew Edmonds,
  • Jennifer Bufford,
  • William Godsoe
Matthew Edmonds
University of Canterbury

Corresponding Author:[email protected]

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Jennifer Bufford
Manaaki Whenua - Landcare Research
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William Godsoe
University of Canterbury
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Abstract

Long-term ecological studies have consistently reported slower than expected changes in biodiversity over time. One explanation for this phenomenon is that commonly used diversity measurements such as species richness are too coarse to detect mechanisms shaping community assembly. It remains unclear whether abundance based diversity measurements are susceptible to the same problem. To test this, we study temporal changes in abundance based diversity indices across 3341 observations from 880 plots from 15 long-term vegetation plot studies. We then partition diversity change into mechanisms of interest to ecologists: selection, drift, and immigration. We show that these mechanisms are an imperfect predictor of temporal diversity change, creating a mismatch between changes in species abundances and changes in diversity, particularly when shifts in diversity are rapid. To resolve this mismatch, we quantify a less studied mechanism “rarity shifts”, which measure how an individual’s contributions to diversity changes over time. We found rarity shifts are an important component of diversity change across many studies. Furthermore, rarity shifts tend to oppose other mechanisms, particularly selection. Therefore, rarity shifts obscure changes in relative abundance from abundance based diversity measurements, revealing why diversity changes appear slower than expected. Ultimately, understanding rarity shifts can lead to a more accurate understanding of the rate and nature of temporal diversity change in ecology and conservation.
23 Jun 2023Submitted to Ecography
28 Jun 2023Submission Checks Completed
28 Jun 2023Assigned to Editor
28 Jun 2023Review(s) Completed, Editorial Evaluation Pending
28 Jun 2023Reviewer(s) Assigned
04 Aug 2023Editorial Decision: Revise Major
31 Aug 20231st Revision Received
01 Sep 2023Submission Checks Completed
01 Sep 2023Assigned to Editor
01 Sep 2023Review(s) Completed, Editorial Evaluation Pending
08 Sep 2023Reviewer(s) Assigned
27 Oct 20232nd Revision Received
27 Oct 2023Submission Checks Completed
27 Oct 2023Assigned to Editor
27 Oct 2023Review(s) Completed, Editorial Evaluation Pending
31 Oct 2023Editorial Decision: Accept