Small-scale effects of annual and woody vegetation on sediment displacement under field conditions

Hoffman, Oren; Yizhaq, Hezi; Boeken, Bertrand

doi:10.1016/j.catena.2013.04.003

Cited by 27 publications

(21 citation statements)

References 53 publications

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“…Similar phenomena were also reported from numerous sandy dune fields (Dougill & Thomas, ; Hesp, ; Langford, ; X. R. Li, Tian, Jia, Zhang, & Liu, ; Nickling & Wolfe, ; Olson, ; Quets et al, ; Seifert et al, ; Tengberg, ; Tengberg & Chen, ; X. P. Wang et al, ; X. P. Wang et al, ; P. Zhang, Yang, Zhao, Bao, & Song, ). Furthermore, on a loessial parent material, sand entrapment (as opposed to silt and clay) is especially apparent (Buis et al, ; Hoffman, Yizhaq, & Boeken, ), pointing to the cardinal role played by plants in trapping sand. Given that sand primarily moves by saltation and silt and clay are transported in suspension (Arens, Van Boxel, & Abuodha, ; Ho, Dupont, El Moctar, & Valance, ; Y. Li & Guo, ), the plant role in trapping sand is quite obvious.…”

Section: Common Paradigmsmentioning

confidence: 99%

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Biocrust research: A critical view on eight common hydrological‐related paradigms and dubious theses

Kidron

2018

Ecohydrology

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Although being relatively young, research on biocrusts has already yielded numerous paradigms and/or dubious theses. The very existence of these “truths” may lead to erroneous conclusions and/or hinder research on these topics. In the current summary, eight paradigms and dubious theses are examined: (a) Biocrusts require physical crusts for establishment; (b) plant establishment is necessary for biocrust establishment on dunes; (c) developmental stages of biocrusts are often regarded as successional stages; (d) climate‐driven crust morphology determines crust hydrology; (e) infiltration (and subsequently run‐off) over biocrusts is determined by soil pores; (f) run‐off in dryland may stem from hydrophobicity; (g) exopolysaccharides trigger infiltration; and (h) mosses impede infiltration and subsequently the growth of perennial plants. During this summary, reasons that lie behind these paradigms and dubious theses are examined using data and/or rationale for a critical analysis. Experimental data, mostly gathered from the Nizzana research site of the Hallamish dune field (Negev Desert, Israel), and published material (mainly from the Tabernas and Tengger deserts) are used. It is argued that most of the paradigms were either based on improper techniques or never thoroughly investigated. The argument presented herein does not necessarily imply that none of the paradigms may take place under very specific conditions but that their acceptance as general “truth” is questionable.

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Section: Common Paradigmsmentioning

confidence: 99%

“…Zhang, Yang, Zhao, Bao, & Song, 2011). Furthermore, on a loessial parent material, sand entrapment (as opposed to silt and clay) is especially apparent (Buis et al, 2010;Hoffman, Yizhaq, & Boeken, 2013), pointing to the cardinal role played by plants in trapping sand.…”

Section: Plant Establishment Is Necessary For Biocrust Establishmenmentioning

confidence: 99%

Biocrust research: A critical view on eight common hydrological‐related paradigms and dubious theses

Kidron

2018

Ecohydrology

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“…In semi‐arid environments, bare ground may be easily erodible while that beneath vegetation patches is more resistant due to root reinforcement (Gyssels et al ., ). Vegetation can also reduce the erosive energy of both rainspash and overland flow: reducing the impact of raindrops (Hoffman et al ., ), reducing the amount of overland flow due to increased infiltration and slowing its velocity due to the roughness imposed by vegetation (Saco and Moreno‐de las Heras, ).…”

Section: Discussionmentioning

confidence: 99%

Quantifying sheet wash erosion rates in a mountainous semi‐arid basin using environmental radionuclides and a stream power model

Geng

Pan

Milledge

et al. 2015

Earth Surf Processes Landf

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Erosion rates and processes define how mountainous landscapes evolve. This study determines the range of erosion rates in a semi‐arid landscape over decadal time spans and defines the dominant processes controlling variability in erosion rates. The varying topography and climatic regimes of the Xiying Basin (Qilian Shan Mountains, China) enables us to examine the relative roles of sheet wash versus rainsplash and the influence of vegetation on soil erosion and deposition. Soil erosion rates since 1954 were determined using 137Cs along 21 transects at four sites with varying gradient, rainfall, and vegetation cover. The mean 137Cs derived soil erosion rate ~0.42 mm/a was consistent with the catchment level erosion rate derived from total sediment yield for a 44 year record. However, there is considerable variability in 137Cs erosion rates both between transects and along transects, perhaps reflecting variation not only in the effectiveness of individual processes but also in their relative roles. We compare the 137Cs‐derived erosion rates with 1‐D models for sediment flux that incorporate sheet wash and rainsplash processes, testing them over a previously untested 60 year timescale. The variability in 137Cs erosion rates along transects is best replicated by sheet wash dominated simulations, suggesting that this is the dominant erosion process in this semi‐arid landscape. The functional form of the sheetwash model can also explain our observations that 137Cs erosion rates decrease with upslope length (i.e. distance down slope) while its variability increases. However, sparsely vegetated sites, located in slightly drier locations, have higher erosion rates, and are not as accurately modeled as densely vegetated sites, suggesting that patchiness of vegetation introduces fine scale variability in erosion rates on these slopes. Copyright © 2015 John Wiley & Sons, Ltd.

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“…Accordingly, we propose that the main ecohydrological role of shrubs is patch creation and maintenance, which is critical under livestock grazing, but loses its importance after herbaceous and shrub cover are decoupled (Guardiola-Clararnonte et al, 2011). Thus, although the direct effect of the shrubs during rainfall is limited to interception of the rainfall itself (Hoffman, Yizhaq, & Boeken, 2013), whatever effects shrub cover has on runoff movement are indirect, via their facilitation of herbaceous plants. These effects are mediated by ground cover and soil structures that control the sink function, such as porosity and hydrophobicity, which are strongly influenced by herbaceous biomass (both green and senescent; Boeken & Orenstein, 2001;Hoffman et al, 2013).…”

Section: The Functional Role Of Vegetation Structure and Patternmentioning

confidence: 99%

Shifts in landscape ecohydrological structural–functional relationship driven by experimental manipulations and ecological interactions

2017

Self Cite

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Vegetation structure and patchiness are central controllers of ecohydrological function in semiarid regions. The feedback interactions between vegetation patchiness and water redistribution make semiarid ecosystems sensitive to state‐shifts, where nonlinearities appear in the structure–function correlations. Hydrological connectivity of runoff sources is functionally important for source–sink interactions over a range of spatial scales and plays a key role in ecosystem state‐shifts. Accordingly, the study of the functional responses of ecosystems to changes in connectivity is important for assessing the system's resilience in response to drivers of degradation. We used runoff data collected over 18 years in experimentally manipulated plots to study both the primary functional response to the manipulations and the changes in both structure and function over two decades. By comparing simultaneous changes in woody and herbaceous cover, biocrust cover and connectivity, and runoff yield, we examined the interactions among the different cover classes and assessed the functional consequences of these interactions. The manipulated changes in vegetation and biocrust cover caused large differences in runoff yields, with positive correlation between biocrust cover and runoff. However, changes in vegetation patterns reduced these differences, as the spread of herbaceous plant cover, at the expense of biocrust and woody cover, caused a shift in the cover–runoff relationship. The landscape was resilient to degradation due to rapid shrub growth in locations of high biocrust cover. On the other hand, a positive feedback of herbaceous plant cover replacing shrub cover caused a state‐shift, likely driven by a combination of drought recurrence and cessation of grazing.

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Small-scale effects of annual and woody vegetation on sediment displacement under field conditions

Cited by 27 publications

References 53 publications

Biocrust research: A critical view on eight common hydrological‐related paradigms and dubious theses

Biocrust research: A critical view on eight common hydrological‐related paradigms and dubious theses

Quantifying sheet wash erosion rates in a mountainous semi‐arid basin using environmental radionuclides and a stream power model

Shifts in landscape ecohydrological structural–functional relationship driven by experimental manipulations and ecological interactions

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