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Measures of Niche Overlap
Author(s) -
Slobodchikoff C. N.,
Schulz William C.
Publication year - 1980
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1936823
Subject(s) - resource (disambiguation) , basis (linear algebra) , estimator , simple (philosophy) , dimension (graph theory) , independence (probability theory) , computer science , interpretation (philosophy) , niche , mathematics , mathematical optimization , ecology , geometry , statistics , pure mathematics , biology , computer network , philosophy , epistemology , programming language
This paper examines the mathematical bases of three commonly used measures of niche overlap along a single resource dimension: curve averaging, asymmetrical α and symmetrical α. Also, we examine the common methods (product α, summation α) for calculating overlap along two or more resource dimensions. The advantage of curve averaging is that it has a simple transition from discrete to continuous data and a simple geometric interpretation, but the method is relatively difficult to apply to a combined overlap along several resource dimensions. The symmetrical α method of computing overlap along a single resource dimension is useful biologically in that it: (1) has a convenient geometric interpretation; (2) is applicable for both discrete and continuous data; (3) provide a mathematical basis for computing overlap along several resource dimensions; and (4) provides a mathematical basis for testing whether patterns of resource use along different resource dimensions are independent. A test for resource independence is developed in this paper. The symmetrical α method, however, measures the patterns of resource uses, and not the actual competitive pressure resulting from niche overlap. A better estimator of competitive pressure is the asymmetrical α method.