The geometric mean of relative abundance indices: a biodiversity measure with a difference

Buckland, S. T., Studeny, A. C., Magurran, A. E., Illian, J. B. and Newson, S. E. (2011) The geometric mean of relative abundance indices: a biodiversity measure with a difference. Ecosphere, 2(9), 100. (doi: 10.1890/ES11-00186.1)

Abstract

The 2010 Biodiversity Target of the Convention on Biological Diversity (CBD), set in 2002, which stated that there should be ‘a significant reduction of the current rate of biodiversity loss' by 2010, highlighted the need for informative and tractable metrics that can be used to evaluate change in biological diversity. While the subsequent Aichi 2020 targets are more wide‐ranging, they also seek to reduce the rate of biodiversity loss. The geometric mean of relative abundance indices, G, is increasingly being used to examine trends in biological diversity and to assess whether biodiversity targets are being met. Here, we explore the mathematical and statistical properties of G that make it useful for judging temporal change in biological diversity, and we discuss its advantages and limitations relative to other measures. We demonstrate that the index reflects trends in both abundance and evenness, and that it is not prone to bias when detectability of individuals varies by species. We note that it allows data from different surveys to be combined to generate a composite index. However, the index exhibits high variance and unstable behaviour when rarely‐recorded species are included in the analyses.

• Item Type: Articles
• Additional Information: AEM would like to acknowledge the support of the European Research Council. ACS' studentship was funded by the University of St Andrews.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Illian, Professor Janine
• Authors: Buckland, S. T., Studeny, A. C., Magurran, A. E., Illian, J. B., and Newson, S. E.
• College/School: College of Science and Engineering > School of Mathematics and Statistics > Statistics
• Journal Name: Ecosphere
• Publisher: Ecological Society of America
• ISSN: 2150-8925
• ISSN (Online): 2150-8925
• Copyright Holders: Copyright © 2011 Buckland et al
• First Published: First published in Ecosphere 2(9):100
• Publisher Policy: Reproduced under a Creative Commons License