A generalised abundance index for seasonal invertebrates

Dennis, Emily B. and Morgan, Byron J. T. and Freeman, Stephen N. and Brereton, Tom and Roy, David B. (2016) A generalised abundance index for seasonal invertebrates. Biometrics, . ISSN 0006-341X. E-ISSN 1541-0420. (doi:https://doi.org/10.1111/biom.12506) (Full text available)


At a time of climate change and major loss of biodiversity, it is important to have efficient tools for monitoring populations. In this context, animal abundance indices play an important role. In producing indices for invertebrates, it is important to account for variation in counts within seasons. Two new methods for describing seasonal variation in invertebrate counts have recently been proposed; one is nonparametric, using generalized additive models, and the other is parametric, based on stopover models. We present a novel generalized abundance index which encompasses both parametric and nonparametric approaches. It is extremely efficient to compute this index due to the use of concentrated likelihood techniques. This has particular relevance for the analysis of data from long-term extensive monitoring schemes with records for many species and sites, for which existing modeling techniques can be prohibitively time consuming. Performance of the index is demonstrated by several applications to UK Butterfly Monitoring Scheme data. We demonstrate the potential for new insights into both phenology and spatial variation in seasonal patterns from parametric modeling and the incorporation of covariate dependence, which is relevant for both monitoring and conservation. Associated R code is available on the journal website.

Item Type: Article
Uncontrolled keywords: Butterflies, citizen science, concentrated likelihood, normal mixtures, phenology
Subjects: Q Science > QA Mathematics (inc Computing science) > QA276 Mathematical statistics
Q Science > QH Natural history > QH541 Ecology
Divisions: Faculties > Sciences > School of Mathematics Statistics and Actuarial Science > Statistics
Depositing User: Byron Morgan
Date Deposited: 03 Mar 2016 16:24 UTC
Last Modified: 19 Oct 2016 13:50 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/54434 (The current URI for this page, for reference purposes)
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