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Optimising biodiversity assessments by volunteers: The application of occupancy modelling to large-scale amphibian surveys

journal contribution
posted on 2023-06-07, 22:41 authored by David Sewell, Trevor J C Beebee, Richard A Griffiths
Mobilising volunteers to carry out biodiversity assessments can help to identify priorities for conservation across broad geographical scales. However, even when volunteers carry out simple presence¿absence surveys, there can be significant issues over false absences and subsequent data interpretation. Simple but scientifically robust protocols are therefore required for these programmes. Here we evaluate amphibian survey protocols for the National Amphibian and Reptile Recording Scheme (NARRS) in Britain, which aims to assess the status of five widespread amphibian species. Surveys were undertaken by trained volunteers and researchers in two contrasting landscapes over 2 years, and occupancy modelling was used to determine covariates of detection, and to optimise the number of surveys and number of methods required. Although surveys need to take into account seasonal and annual changes in the detectability of different species, there were also landscape effects. Frogs and toads were generally harder to detect in ponds in Kent than in Wales, while the converse was true of newts. Adding bottle-trapping to the suite of methods increased the detection of smooth and palmate newts in both areas, and of great crested newts in Wales. Overall, reliable assessment of the presence or absence of all five species at a site required four separate surveys, each using four different methods (visual encounter surveys during both day and night, dip netting and bottle-trapping). Our approach may prove useful for finding the best compromises between rigor and simplicity when volunteers are used in large-scale surveys.

History

Publication status

  • Published

Journal

Biological Conservation

ISSN

0006-3207

Issue

9

Volume

143

Page range

2102-2110

Pages

9.0

Department affiliated with

  • Evolution, Behaviour and Environment Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2012-02-06

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