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Lookup NU author(s): Professor Giles Budge
This is the authors' accepted manuscript of an article that has been published in its final definitive form by Wiley-Blackwell Publishing Ltd, 2017.
For re-use rights please refer to the publisher's terms and conditions.
© 2017 British Ecological Society. Ecological processes operating on large spatio-temporal scales are difficult to disentangle with traditional empirical approaches. Alternatively, researchers can take advantage of 'natural' experiments, where experimental control is exercised by careful site selection. Recent advances in developing protocols for designing these 'pseudo-experiments' commonly do not consider the selection of the focal region and predictor variables are usually restricted to two. Here, we advance this type of site selection protocol to study the impact of multiple landscape scale factors on pollinator abundance and diversity across multiple regions. Using datasets of geographic and ecological variables with national coverage, we applied a novel hierarchical computation approach to select study sites that contrast as much as possible in four key variables, while attempting to maintain regional comparability and national representativeness. There were three main steps to the protocol: (i) selection of six 100 × 100 km2 regions that collectively provided land cover representative of the national land average, (ii) mapping of potential sites into a multivariate space with axes representing four key factors potentially influencing insect pollinator abundance, and (iii) applying a selection algorithm which maximized differences between the four key variables, while controlling for a set of external constraints. Validation data for the site selection metrics were recorded alongside the collection of data on pollinator populations during two field campaigns. While the accuracy of the metric estimates varied, the site selection succeeded in objectively identifying field sites that differed significantly in values for each of the four key variables. Between-variable correlations were also reduced or eliminated, thus facilitating analysis of their separate effects. This study has shown that national datasets can be used to select randomized and replicated field sites objectively within multiple regions and along multiple interacting gradients. Similar protocols could be used for studying a range of alternative research questions related to land use or other spatially explicit environmental variables, and to identify networks of field sites for other countries, regions, drivers and response taxa in a wide range of scenarios.
Author(s): Gillespie MAK, Baude M, Biesmeijer J, Boatman N, Budge GE, Crowe A, Memmott J, Morton RD, Pietravalle S, Potts SG, Senapathi D, Smart SM, Kunin WE
Publication type: Article
Publication status: Published
Journal: Methods in Ecology and Evolution
Print publication date: 08/11/2017
Online publication date: 05/04/2017
Acceptance date: 16/03/2017
Date deposited: 25/07/2017
ISSN (electronic): 2041-210X
Publisher: Wiley-Blackwell Publishing Ltd
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