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Impacts of pollution and climate change on ombrotrophic Sphagnum species in the UK: analysis of uncertainties in two empirical niche models

Smart, S.M.; Henrys, P.A.; Scott, W.A.; Hall, J.R.; Evans, C.D.; Crowe, A.; Rowe, E.C.; Dragosits, U.; Page, T.; Whyatt, J.D.; Sowerby, A.; Clark, J.M.. 2010 Impacts of pollution and climate change on ombrotrophic Sphagnum species in the UK: analysis of uncertainties in two empirical niche models. Climate Research, 45. 163-177. 10.3354/cr00969

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Abstract/Summary

A significant challenge in the prediction of climate change impacts on ecosystems and biodiversity is quantifying the sources of uncertainty that emerge within and between different models. Statistical species niche models have grown in popularity, yet no single best technique has been identified reflecting differing performance in different situations. Our aim was to quantify uncertainties associated with the application of 2 complimentary modelling techniques. Generalised linear mixed models (GLMM) and generalised additive mixed models (GAMM) were used to model the realised niche of ombrotrophic Sphagnum species in British peatlands. These models were then used to predict changes in Sphagnum cover between 2020 and 2050 based on projections of climate change and atmospheric deposition of nitrogen and sulphur. Over 90% of the variation in the GLMM predictions was due to niche model parameter uncertainty, dropping to 14% for the GAMM. After having covaried out other factors, average variation in predicted values of Sphagnum cover across UK peatlands was the next largest source of variation (8% for the GLMM and 86% for the GAMM). The better performance of the GAMM needs to be weighed against its tendency to overfit the training data. While our niche models are only a first approximation, we used them to undertake a preliminary evaluation of the relative importance of climate change and nitrogen and sulphur deposition and the geographic locations of the largest expected changes in Sphagnum cover. Predicted changes in cover were all small (generally <1% in an average 4 m2 unit area) but also highly uncertain. Peatlands expected to be most affected by climate change in combination with atmospheric pollution were Dartmoor, Brecon Beacons and the western Lake District.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.3354/cr00969
Programmes: CEH Topics & Objectives 2009 onwards > Biodiversity > BD Topic 2 - Ecological Processes in the Environment
CEH Sections: Billett
Emmett
Parr
ISSN: 0936-577X
Additional Information. Not used in RCUK Gateway to Research.: Cliamte Research is an Open Access journal and full text can be accessed via the OFFICIAL URL link
Additional Keywords: nitrogen, sulphur, generalised linear model, generalised additive model, uncertainty, large scale, peatlands, UKCP09, UKCIP02
NORA Subject Terms: Botany
Ecology and Environment
Date made live: 19 Jan 2011 16:11
URI: http://nora.nerc.ac.uk/id/eprint/13097

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