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International Journal of Ecology
Volume 2010 (2010), Article ID 826475, 13 pages
http://dx.doi.org/10.1155/2010/826475
Research Article

Determining Boundaries between Abundance Biozones Using Minimal Equipment

1Petroleum Geoscience Programme, Department of Chemical Engineering, Faculty of Engineering, The University of the West Indies, St. Augustine, Trinidad and Tobago
2Department of Land Science and Surveying, Faculty of Engineering, The University of the West Indies, St. Augustine, Trinidad and Tobago

Received 26 February 2010; Accepted 12 May 2010

Academic Editor: Mariana Amato

Copyright © 2010 Brent Wilson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The areal extent of a biological community is usually determined using statistical techniques that only give reliable results where samples contain similar and high numbers of specimens. This paper presents a simple, inexpensive method for determining the geographical limits of biological communities applicable where adjacent samples contain widely differing numbers of specimens. The method is a development of SHE Analysis, which discerns boundaries between adjacent abundance biozones (ABs), an AB being an area with a distinct community structure. As originally conceived, SHEbi (SHE Analysis for the identification of Biozones) commences with species' absolute abundances and works best with large samples of equal sizes. If the variance in 𝑁 (per sample) is high, SHEbi may place AB boundaries in unexpected locations. A modification, based on proportional abundances, is developed here using species' proportional abundances ( 𝑝 𝑖 = 𝑛 𝑖 / 𝑁 ) for each sample where 𝑛 𝑖 is the number of specimens in the ith species in the sample. For intertidal foraminifera from the Caroni Swamp, Trinidad, where 𝑁 , the number of specimens, fluctuates widely between samples, the modification (SHEbip) gives ecologically more sensible results than does traditional SHEbi.