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Extreme rarity of competitive exclusion in modern and fossil marine benthic ecosystems

Adiel A. Klompmaker and Seth Finnegan
Extreme rarity of competitive exclusion in modern and fossil marine benthic ecosystems
Geology (Boulder) (August 2018) 46 (8): 723-726


Competitive interactions have been invoked as major drivers of ecological and evolutionary trends through time, but the strength and frequency of such interactions is notoriously difficult to evaluate. Here we use inferences from species co-occurrence patterns to determine the frequency of the extreme endmember of competition-competitive exclusion-in modern and fossil benthic marine invertebrate assemblages. Within environmentally and temporally well-constrained species pools, we examine the percentage of all species pairs that co-occur less often than expected by chance (segregated pairs) as a maximum measure of competitive exclusion. Segregated pairs are very rare, with most assemblages containing none, and the frequency of segregated pairs shows no trend throughout the Phanerozoic. Contrary to the competition-relatedness hypothesis, we find little evidence that segregated pairs are more common among closely related species except potentially for congeneric pairs in deeper water settings where physical disturbance is relatively low. Although taphonomy, post-mortem transport, and time-averaging could obscure original co-occurrence patterns, analyses suggest that these factors are unlikely to fully explain the low frequency of segregated pairs. Our findings support the hypothesis that predation and disturbance keep marine benthic communities below carrying capacity and thus reduce the potential for competitive interactions to dictate community composition in shallow waters.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 46
Serial Issue: 8
Title: Extreme rarity of competitive exclusion in modern and fossil marine benthic ecosystems
Affiliation: University of California at Berkeley, Department of Integrative Biology, Berkeley, CA, United States
Pages: 723-726
Published: 20180801
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 57
Accession Number: 2018-083851
Categories: General paleontology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2018261
Illustration Description: illus.
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201821
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