Greater local diversity under older species pools may arise from enhanced competitive equivalence. (20th November 2020)

• Record Type: Journal Article
• Authors: Leopold, Devin R.; Fukami, Tadashi
• Editors: Coulson, Tim
• Is Part Of: Ecology letters. Volume 24:Number 2(2021)
• Page Start: 310
• Page End: 318
• Publication Date: 2020-11-20
• Subjects: biodiversity -- chronosequence -- coexistence -- community assembly -- functional diversity -- regional species pool; Ecology -- Periodicals; 577
• DOI: 10.1111/ele.13647
• Languages: English
• ISSNs: 1461-023X

Abstract

Abstract: Ecological communities typically contain more species when located within geologically older regions. This pattern is traditionally attributed to the long‐term accumulation of species in the regional species pool, with local species interactions playing a minor role. We provide evidence suggesting a more important role of local species interactions than generally assumed. We assembled 320 communities of root‐associated fungi under 80 species pools, varying species pool richness and the mean age of the sites from which the fungi were collected across a 4‐myr soil chronosequence. We found that local diversity increased more with increasing species pool richness when species were from older sites. We also found that older species pools had lower functional and phylogenetic diversity, indicating greater competitive equivalence among species. Our results suggest that older regions have higher local richness not simply because older pools are more speciose but also because species have evolved traits that allow them to locally co‐occur. Abstract : We present the results of an experiment that challenges the widely held belief that greater local biodiversity in geologically older regions can be explained by older regions having greater regional species richness. Using experimental manipulations of microbial communities in laboratory microcosms, we show that an additional cause of greater local diversity in older regions is that the constituent species of older regional species pools are more likely to have evolved traits that allow local co‐occurrence. Our results suggest a greater role of local species interactions in the formation of regional species pools than has been previously thought.