Simultaneous confidence intervals for comparing biodiversity indices estimated from overdispersed count data

authored by: Ralph Scherer, Frank Schaarschmidt, Sabine Prescher, Kai U. Priesnitz
Abstract: Diversity indices might be used to assess the impact of treatments on the relative abundance patterns in species communities. When several treatments are to be compared, simultaneous confidence intervals for the differences of diversity indices between treatments may be used. The simultaneous confidence interval methods described until now are either constructed or validated under the assumption of the multinomial distribution for the abundance counts. Motivated by four example data sets with background in agricultural and marine ecology, we focus on the situation when available replications show that the count data exhibit extra-multinomial variability. Based on simulated overdispersed count data, we compare previously proposed methods assuming multinomial distribution, a method assuming normal distribution for the replicated observations of the diversity indices and three different bootstrap methods to construct simultaneous confidence intervals for multiple differences of Simpson and Shannon diversity indices. The focus of the simulation study is on comparisons to a control group. The severe failure of asymptotic multinomial methods in overdispersed settings is illustrated. Among the bootstrap methods, the widely known Westfall-Young method performs best for the Simpson index, while for the Shannon index, two methods based on stratified bootstrap and summed count data are preferable. The methods application is illustrated for an example.
Organisation(s): Department of Biostatistics
External Organisation(s): Hannover Medical School (MHH)
Julius Kühn Institute (JKI) Federal Research Centre for Cultivated Plants
Bavarian State Research Center for Agriculture (LfL)
Type: Article
Journal: Biometrical Journal
Volume: 55
Pages: 246-263
No. of pages: 18
ISSN: 0323-3847
Publication date: 03.2013
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Statistics and Probability, Statistics, Probability and Uncertainty
Sustainable Development Goals: SDG 14 - Life Below Water
Electronic version(s): https://doi.org/10.1002/bimj.201200157 (Access: Closed)