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Coupling vegetation organization patterns to soil resource heterogeneity in a central Kenyan dryland using geophysical imagery

Franz, Trenton E.; King, Elizabeth G.; Caylor, Kelly K.; Robinson, David A.. 2011 Coupling vegetation organization patterns to soil resource heterogeneity in a central Kenyan dryland using geophysical imagery. Water Resources Research, 47, W07531. 18, pp. 10.1029/2010WR010127

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Abstract/Summary

In dryland ecosystems, understanding the effects of heterogeneity in soil moisture and geophysical properties on vegetation structure and dynamics poses a suite of challenging research questions. Heterogeneity in soil depth can affect resource availability and the subsequent organization of woody vegetation, while spatiotemporal variation in soil moisture can reveal important ecohydrological feedbacks that govern the outcome of anthropogenic activities on the organization of dryland vegetation. In this research we investigate two cases of soil resource heterogeneity that affect the organization of dryland vegetation patterns by expanding previous electromagnetic induction (EMI) imaging techniques. In the first case we examine the influence of soil depth as a control on soil resource availability on hillslopes in tree-grass systems in central Kenya. Our results indicate that woody vegetation clumping occurs where soil depth changes, and the deeper rooted Acacia tortilis occurs on deep soils while the drought tolerant Acacia etbaica occurs on shallow soils. In the second case we examine daily patch–interpatch scale moisture dynamics following two different-sized rain events in a degraded landscape. With the aid of a numerical subsurface flow model, EMI, and soil moisture data, we have identified a possible positive feedback mechanism (‘soil moisture halo effect’) that we believe may have contributed to the proliferation and two-phase pattern formation of a native succulent Sansevieria volkensii in degraded ecosystems of Kenya. By determining how different plants respond to, and modify, the soil environment, we can better understand resource capture and dynamics, which in the longterm will help to develop management strategies.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1029/2010WR010127
Programmes: CEH Topics & Objectives 2009 - 2012 > Water > WA Topic 2 - Ecohydrological Processes > WA - 2.1 - Identify and quantify sources, fluxes and pathways of water, chemicals ...
CEH Topics & Objectives 2009 - 2012 > Biogeochemistry > BGC Topic 1 - Monitoring and Interpretation of Biogeochemical and Climate Changes > BGC - 1.4 - Develop innovative, effective methods for monitoring fluxes, exposure and effects
CEH Sections: Emmett
ISSN: 0043-1397
Additional Keywords: Sansevieria volkensii, spatial patterns, ecohydrology, geophysics, electromagnetic induction, soil moisture
NORA Subject Terms: Agriculture and Soil Science
Ecology and Environment
Date made live: 30 Aug 2011 10:30
URI: http://nora.nerc.ac.uk/id/eprint/15006

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