Soil stabilization linked to plant diversity and environmental context in coastal wetlands

Ford, H., Garbutt, A., Ladd, C. , Malarkey, J. and Skov, M. W. (2016) Soil stabilization linked to plant diversity and environmental context in coastal wetlands. Journal of Vegetation Science, 27(2), pp. 259-268. (doi: 10.1111/jvs.12367) (PMID:27867297) (PMCID:PMC5111397)

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Background: Plants play a pivotal role in soil stabilization, with above‐ground vegetation and roots combining to physically protect soil against erosion. It is possible that diverse plant communities boost root biomass, with knock‐on positive effects for soil stability, but these relationships are yet to be disentangled. Question: We hypothesize that soil erosion rates fall with increased plant species richness, and test explicitly how closely root biomass is associated with plant diversity. Methods: We tested this hypothesis in salt marsh grasslands, dynamic ecosystems with a key role in flood protection. Using step‐wise regression, the influences of biotic (e.g. plant diversity) and abiotic variables on root biomass and soil stability were determined for salt marshes with two contrasting soil types: erosion‐resistant clay (Essex, southeast UK) and erosion‐prone sand (Morecambe Bay, northwest UK). A total of 132 (30‐cm depth) cores of natural marsh were extracted and exposed to lateral erosion by water in a re‐circulating flume. Results: Soil erosion rates fell with increased plant species richness (R2 = 0.55), when richness was modelled as a single explanatory variable, but was more important in erosion‐prone (R2 = 0.44) than erosion‐resistant (R2 = 0.18) regions. As plant species richness increased from two to nine species·m−2, the coefficient of variation in soil erosion rate decreased significantly (R2 = 0.92). Plant species richness was a significant predictor of root biomass (R2 = 0.22). Step‐wise regression showed that five key variables accounted for 80% of variation in soil erosion rate across regions. Clay‐silt fraction and soil carbon stock were linked to lower rates, contributing 24% and 31%, respectively, to variation in erosion rate. In regional analysis, abiotic factors declined in importance, with root biomass explaining 25% of variation. Plant diversity explained 12% of variation in the erosion‐prone sandy region. Conclusion: Our study indicates that soil stabilization and root biomass are positively associated with plant diversity. Diversity effects are more pronounced in biogeographical contexts where soils are erosion‐prone (sandy, low organic content), suggesting that the pervasive influence of biodiversity on environmental processes also applies to the ecosystem service of erosion protection.

Item Type:Articles
Additional Information:This study presents data collected as part of the Coastal Biodiversity and Ecosystem Service Sustainability project (CBESS: NE/J015644/1), part of the BESS programme; a 6‐yr programme (2011–2017) funded by the Natural Environment Research Council (Bangor University grant reference: NE/J015350/1) and the Biotechnology and Biological Sciences Research Council (BBSRC) as part of the UK's Living with Environmental Change (LWEC) programme. The views expressed are those of the authors and do not reflect the views of BESS Directorate or NERC. J.M. was funded by the NERC COHBED project (NE/1027223/1). M.W.S. and A.G. acknowledge financial support from the Welsh Government and Higher Education Funding Council for Wales through the Sêr Cymru National Research Network for Low Carbon, Energy and Environment.
Glasgow Author(s) Enlighten ID:Ladd, Dr Cai
Authors: Ford, H., Garbutt, A., Ladd, C., Malarkey, J., and Skov, M. W.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Journal of Vegetation Science
ISSN (Online):1654-1103
Published Online:04 January 2016
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Journal of Vegetation Science 27(2): 259-268
Publisher Policy:Reproduced under a Creative Commons License

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