Defining landscape resistance values in least-cost connectivity models for the invasive grey squirrel: a comparison of approaches using expert-opinion and habitat suitability modelling

Stevenson-Holt, Claire D. ORCID: https://orcid.org/0000-0003-3635-5404 , Watts, Kevin, Bellamy, Chloe C., Nevin, Owen ORCID: https://orcid.org/0000-0003-3513-8053 and Ramsey, Andrew D. ORCID: https://orcid.org/0000-0002-5550-9977 (2014) Defining landscape resistance values in least-cost connectivity models for the invasive grey squirrel: a comparison of approaches using expert-opinion and habitat suitability modelling. PLoS ONE, 9 (11). e112119.

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Abstract

Least-cost models are widely used to study the functional connectivity of habitat within a varied landscape matrix. A critical step in the process is identifying resistance values for each land cover based upon the facilitating or impeding impact on species movement. Ideally resistance values would be parameterised with empirical data, but due to a shortage of such information, expert-opinion is often used. However, the use of expert-opinion is seen as subjective, human-centric and unreliable. This study derived resistance values from grey squirrel habitat suitability models (HSM) in order to compare the utility and validity of this approach with more traditional, expert-led methods. Models were built and tested with MaxEnt, using squirrel presence records and a categorical land cover map for Cumbria, UK. Predictions on the likelihood of squirrel occurrence within each land cover type were inverted, providing resistance values which were used to parameterise a least-cost model. The resulting habitat networks were measured and compared to those derived from a least-cost model built with previously collated information from experts. The expert-derived and HSM-inferred least-cost networks differ in precision. The HSM-informed networks were smaller and more fragmented because of the higher resistance values attributed to most habitats. These results are discussed in relation to the applicability of both approaches for conservation and management objectives, providing guidance to researchers and practitioners attempting to apply and interpret a least-cost approach to mapping ecological networks.

Item Type:	Article
Journal / Publication Title:	PLoS ONE
Publisher:	Public Library of Science
ISSN:	1932-6203
Departments:	Academic Departments > Science, Natural Resources & Outdoor Studies (SNROS) > Forestry and Conservation
Additional Information:	© 2014 Stevenson-Holt et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Depositing User:	Insight Administrator
Date Deposited:	18 Dec 2014 13:56
Last Modified:	12 Jan 2024 13:16
URI:	https://insight.cumbria.ac.uk/id/eprint/1643

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