Polarization of competition increases with latitude

Barnes, David K.A. ORCID: 2002 Polarization of competition increases with latitude. Proceedings of the Royal Society of London, Series B, 269 (1504). 2061-2069.

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Many organisms overlap in their use of resources in space and time. Where and when resources are restricted, species must compete for them. Living space, often a critical resource controlling food and mate availability, is directly contested by organisms in most habitats. The ensuing animal interactions generally result in a winner gaining space and a loser, which may die. Contact matrices from studies of interference competition in encrusting marine Bryozoa (clonal and colonial animals), spanning at least 60degrees latitude in both hemispheres, were analysed and subjected to a modern transitivity index. Only data for Bryozoa were used because (i) use of a single taxon with restricted ecology simplifies the scope for types of encounters, (and therefore) interpretation; and (ii) ecological bias is reduced because bryozoans are abundant at all latitudes. The analysis shows that assemblage competition is more hierarchical towards both poles. Thus, poorer competitors fail more frequently in interactions with increasing latitude. The cause of this trend is the simplification of overall outcomes between competitors, such as fewer ties, reversals in outcome or competitive loops (where low-ranking competitors beat those of higher ranking). The implication of such a trend is that the maintenance of biological diversity at high latitudes may principally be by physical rather than biological (competition) processes. Certainly, ocean surface energy increases with latitude through wind and wave action (and ice scour in polar regions).

Item Type: Publication - Article
Digital Object Identifier (DOI):
Programmes: BAS Programmes > Antarctic Science in the Global Context (2000-2005) > Life at the Edge - Stresses and Thresholds
ISSN: 0962-8452
Additional Keywords: interference competition; hierarchies; transitivity; disturbance
NORA Subject Terms: Biology and Microbiology
Ecology and Environment
Date made live: 20 Sep 2011 14:26 +0 (UTC)

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