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Competition on a divided and ephemeral resource: Testing the Assumptions. II. Association

Shorrocks, Bryan; Rosewell, Jonathan and Edwards, Kathy (1990). Competition on a divided and ephemeral resource: Testing the Assumptions. II. Association. Journal of Animal Ecology, 59(3) pp. 1003–1017.

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(1) We test the assumption of the aggregation model of coexistence on a divided and ephemeral resource that there is no association between species.

(2) We test associations by presence and absence from patches using 2 x 2 contingency tables and the chi-squared statistic. As a convenient index of association we use the four-point correlation coefficient phi = sqrt(chi-squared/N) where N is the number of observations (patches) in the corresponding contingency table and chi-squared is the uncorrected statistic.

(3) The data, from laboratory experiments, field experiments and field collections shows no evidence of association between species pairs. Out of 157 comparisons, only eight show significant associations at the 5% level.

(4) We incorporate phi into the original aggregation model for two-species competition and into the guild-size extension and examine its influence. Probability refuges and resource refuges are therefore brought together within one conceptual framework.

Item Type: Journal Article
ISSN: 0021-8790
Keywords: probability refuge; resource refuge; interspecific competition; aggregation; population dynamics; patchy environment;
Academic Unit/Department: Mathematics, Computing and Technology > Computing & Communications
Mathematics, Computing and Technology
Interdisciplinary Research Centre: Centre for Research in Education and Educational Technology (CREET)
Item ID: 17347
Depositing User: Jonathan Rosewell
Date Deposited: 02 Jul 2009 15:42
Last Modified: 15 Jan 2016 11:32
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