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Diversity partitioning in Permian and Early Triassic benthic ecosystems of the Western USA: a comparison


Hofmann, Richard; Hautmann, Michael; Bucher, Hugo (2017). Diversity partitioning in Permian and Early Triassic benthic ecosystems of the Western USA: a comparison. Historical biology, 29(7):918-930.

Abstract

This paper compares the relative contributions of within-habitat diversity [alpha-diversity] and betweenhabitat- diversity [beta-diversity] to regional diversity [gamma-diversity] in marine benthic communities of the western US before and after the end-Permian mass extinction. We found that presumably coolwater faunas from the Permian Gerster Limestone and the Park City Formation had low alpha- and betadiversities, comparable to those of low diverse faunas of the Early Triassic. In contrast, tropical Permian faunas had much higher alpha-diversities and a variable pattern of beta-diversity: Whereas faunas of spacelimited bioherms show a positive correlation between beta-diversity and gamma-diversity, beta-diversity in level-bottom faunas is elevated only when gamma-diversity is very high (>250 species). This contrasting pattern probably reflects differential effects of interspecific competition on habitat partitioning. In lowcompetitive level-bottom faunas, species are able to coexist until competition forces species into their ecological optima, thereby increasing beta-diversity. This effect occurs at much lower gamma-diversities in more competitive reef-bound faunas, causing the observed positive correlation between beta- and gamma-diversity. We suggest that differences in the level of interspecific competition and hence diversity partitioning between Permian and Triassic benthic communities result from the higher average metabolic rates in the Mesozoic mollusc-dominated benthos in contrast to their Permian counterparts.

Abstract

This paper compares the relative contributions of within-habitat diversity [alpha-diversity] and betweenhabitat- diversity [beta-diversity] to regional diversity [gamma-diversity] in marine benthic communities of the western US before and after the end-Permian mass extinction. We found that presumably coolwater faunas from the Permian Gerster Limestone and the Park City Formation had low alpha- and betadiversities, comparable to those of low diverse faunas of the Early Triassic. In contrast, tropical Permian faunas had much higher alpha-diversities and a variable pattern of beta-diversity: Whereas faunas of spacelimited bioherms show a positive correlation between beta-diversity and gamma-diversity, beta-diversity in level-bottom faunas is elevated only when gamma-diversity is very high (>250 species). This contrasting pattern probably reflects differential effects of interspecific competition on habitat partitioning. In lowcompetitive level-bottom faunas, species are able to coexist until competition forces species into their ecological optima, thereby increasing beta-diversity. This effect occurs at much lower gamma-diversities in more competitive reef-bound faunas, causing the observed positive correlation between beta- and gamma-diversity. We suggest that differences in the level of interspecific competition and hence diversity partitioning between Permian and Triassic benthic communities result from the higher average metabolic rates in the Mesozoic mollusc-dominated benthos in contrast to their Permian counterparts.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Paleontological Institute and Museum
Dewey Decimal Classification:560 Fossils & prehistoric life
Language:English
Date:2017
Deposited On:14 Dec 2016 16:49
Last Modified:19 Aug 2018 05:42
Publisher:Taylor & Francis
ISSN:0891-2963
OA Status:Closed
Publisher DOI:https://doi.org/10.1080/08912963.2016.1263626
Project Information:
  • : FunderSNSF
  • : Grant ID200021_149152
  • : Project TitleChanges of palaeocommunity structure and diversity partitioning in benthic marine communities during the Palaeozoic-Mesozoic transition

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