Ecogeomorphic Feedbacks in Semiarid Rangelands: A Review

doi:10.1016/S1002-0160(09)60111-9

Pedosphere

Volume 19, Issue 2, April 2009, Pages 217-229

https://doi.org/10.1016/S1002-0160(09)60111-9 Get rights and content

Abstract

The ecogeomorphic processes occurring on semiarid rangelands are reviewed, with emphasis on the source-sink relations and positive feedback loops that existed between shrub patches and intershrub areas, and the way livestock presence affected these interactions. Compared with intershrub areas, the shrub patches had a higher soil porosity, infiltration capacity, water-holding capacity, hydraulic conductivity, structural stability, and organic matter content, and lower bulk density. These differences derived from a host of processes whose intensity was less in the shrub patches, including raindrop impact, mechanical crust formation, overland water flow, soil erosion, evaporative moisture loss, and flock trampling. There was also greater shading of the soil surface; soil and litter deposition; water accumulation; microbial, fungal, and mesofaunal activities in the shrub patches. The overland flow of water carried soil and litter from the intershrub areas to the shrub patches and resulted in microtopographic modifications that tended to strengthen these source-sink relations. Grazing had an impact on these processes, not only at the shrub-intershrub scale but also within the intershrub areas, through the creation of highly compacted trampling routes. The combined role of the above ecogeomorphic processes was to maintain the rangeland's functionality. Without these inter-relationships, water loss, soil erosion, and nutrient depletion would occur at the hillside scale, causing degradation of the landscape.

References (88)

N.A.L. Archer et al.
Below-ground relationships of soil texture, roots and hydraulic conductivity in two-phase mosaic vegetation in south-east Spain
J. Arid Environ.
(2002)
G. Bergkamp
A hierarchical view of the interactions of runoff and infiltration with vegetation and microtopography in semiarid shrublands
Catena.
(1998)
E. Bochet et al.
Modified topsoil islands within patchy Mediterranean vegetation in SE Spain
Catena.
(1999)
C. Boix-Fayos et al.
Influence of soil properties on the aggregation of some Mediterranean soils and the use of aggregate size and stability as land degradation indicators
Catena.
(2001)
J. Bromley et al.
The role of surface water redistribution in an area of patterned vegetation in a semi-arid environment, south-west Niger
J. Hydrol.
(1997)
M.F. Brown et al.
The effects of termites and straw mulch on soil nitrogen in a creosote bush (Larrea tridentata) dominated Chihuahuan Desert ecosystem
J. Arid Environ.
(2003)
R.B. Bryan
Soil erodibility and processes of water erosion on hillslope
Geomorphology.
(2000)
L. Descroix et al.
Influence of soil surface features and vegetation on runoff and erosion in the Western Sierra Madre (Duango, Northwest Mexico)
Catena.
(2001)
D.A. Devitt et al.
Root channel macropores enhance downward movement of water in the Mojave Desert ecosystem
J. Arid Environ.
(2002)
D.L. Dunkerley
Banded vegetation: Survival under drought and grazing pressure based on a simple cellular automaton model
J. Arid Environ.
(1997)

D.L. Dunkerley et al.

Runoff and runon areas in a patterned chenopod shrubland, arid western New South Wales, Australia: Characteristics and origin

J. Arid Environ.

(1995)

D.J. Eldridge et al.

Infiltration through three contrasting biological soil crusts in patterned landscapes in the Negev, Israel

Catena.

(2000)

W. Garner et al.

A proposed mechanism for the formation of “fertile islands” in the desert ecosystem

J. Arid Environ.

(1989)

A.C. Imeson et al.

Soil erosion and climate change: The transect approach and the influence of scale

Geomorphology.

(1998)

E.C. Jackson et al.

Desertification and biopedoturbation in the northern Chihuahuan Desert

J. Arid Environ.

(2003)

J.L. Janeau et al.

The soil surface characteristics of vegetation stripes in Northern Mexico and their influences on the system hydrodynamics—An experimental approach

Catena.

(1999)

S.N. Krogh et al.

Presence/absence of a keystone species as an indicator of rangeland health

J. Arid Environ.

(2002)

R. Lefever et al.

On the origin of tiger bush

B. Math. Biol.

(1997)

X. Li et al.

Arylsulfatase activity of soil microbial biomass along a Mediterranean-arid transect

Soil Biol. Biochem.

(2003)

X. Li et al.

Enzyme activities along a climatic transect in the Judean Desert

Catena.

(2003)

J.A. Ludwig et al.

Stripes, strands or stipples: Modelling the influence of three landscape banding patterns on resource capture and productivity in semi-arid woodlands, Australia

Catena.

(1999)

J.A. Mabbutt et al.

Vegetation banding in arid Western Australia

J. Arid Environ.

(1987)

E. Martinez-Meza et al.

Stemflow, throughfall and channelization of stemflow by roots in three Chihuahuan desert shrubs

J. Arid Environ.

(1996)

A. Mauchamp et al.

Water funneling by the crown of Flourensia cernua, a Chihuahuan Desert shrub

J. Arid Environ.

(1993)

J.M. Nicolau et al.

Effects of soil and vegetation on runoff along a catena in semi-arid Spain

Geomorphology.

(1996)

W.L. Nutting et al.

Physical and chemical alteration of soil by two subterranean termite species in Sonoran Desert grassland

J. Arid Environ.

(1987)

L.W. Parker et al.

The effects of subterranean termite removal on desert soil nitrogen and ephemeral flora

J. Arid Environ.

(1982)

M.J.M. Römkens et al.

Rain infiltration into loess soils from different geographic regions

Catena.

(1995)

G. Sanchez et al.

Interactions of plant growth and sediment movement on slopes in a semi-arid environment

Geomorphology.

(1994)

P. Sarah et al.

Soil structure variations under manipulations of water and vegetation

J. Arid Environ.

(2004)

S. Sarig et al.

Immediate effect of wetting event on microbial biomass and carbohydrate production-mediated aggregation in desert soil

Geoderma.

(1993)

W.H. Schlesinger et al.

Soil moisture content and plant transpiration in the Chihuahuan desert of New Mexico

J. Arid Environ.

(1987)

I. Stavi et al.

Surface microtopography and soil penetration resistance associated with shrub patches in a semiarid rangeland

Geomorphology.

(2008)

I. Stavi et al.

Grazing-induced spatial variability of soil bulk density and content of moisture, organic carbon and calcium carbonate in a semi-arid rangeland

Catena.

(2008)

S.W. Trimble et al.

The cow as geomorphic agent—A critical review

Geomorphology.

(1995)

J.M. Tromble

Water interception by two arid land shrubs

J. Arid Environ.

(1988)

C. Valentin et al.

Soil and water components of banded vegetation patterns

Catena.

(1999)

M. Weltz et al.

Flash grazing and trampling: Effects on infiltration rates and sediment yield on a selected New Mexico range site

J. Arid Environ.

(1989)

W.G. Whitford et al.

Stemflow contribution to the “fertile island” effect in creosotebush, Larrea tridentata

J. Arid Environ.

(1997)

H. Yizhaq et al.

Banded vegetation: Biological productivity and resilience

Physica A.

(2005)

E. Zaady et al.

Litter as a regulator of N and C dynamics in macrophytic patches in Negev desert soils

Soil Biol. Biochem.

(1996)

E.W. Bhark et al.

Association between plant canopies and the spatial patterns of infiltration in shrubland and grassland of the Chihuahuan desert, New Mexico

Ecosystems.

(2003)

J.M. Bradford et al.

Effect of soil surface sealing on splash from a single waterdrop

Soil Sci. Soc. Am. J.

(1986)

D.D. Breshears et al.

Overstory-imposed heterogeneity in solar radiation and soil moisture in a semiarid woodland

Ecol. Appl.

(1997)

Cited by (56)

Grazing Influences on Geomorphic Systems
2022, Treatise on Geomorphology
Grazing by wild and domesticated animals can have profound geomorphic impacts on the landscape and grazing by feral animals may also have substantial geomorphic impacts, although more research is needed in this area. Wild grazers, such as native ungulates including mountain goats and elk, are increasingly restricted in their range to nature preserves where their concentrated numbers can produce severe localized erosion, although the reintroduction of natural predators in some areas may reverse this trend. Feral animals, such as wild horses and burros, are grazers that produce erosional impacts in sensitive sites such as arid or semi-arid climates and on coastal dunes. Domesticated grazers, including especially cattle and sheep, impact widespread geographic areas, and produce geomorphic impacts through trampling and compaction of soil leading to accelerated runoff and gullying, disruption of streambed vegetation, chiseling and sloughing of streambanks, disruption of protective soil crusts, and terracette formation.
Soil loss from small rangeland plots under simulated rainfall and run-on conditions
2020, Geoderma
In order to predict and mitigate soil erosion it is necessary to understand the mechanism of detachment by raindrops and by shallow flow. The relative contribution of these drivers to the overall erosion process on arid rangelands is not well understood and field experimental data is limited. The experiment was conducted using simulated rainfall and overland flow on 56 small (2 m × 6 m) natural plots located on 7 rangeland sites in Arizona, USA. The goals of the study were (i) to compare raindrop driven and shallow flow driven erosion rates on arid rangeland, and (ii) assess the role of flow hydraulics, vegetation, and cover on attenuation of erosive impact of raindrops. A total of 520 measurements of steady state flow under two treatments (rainfall and run-on) were obtained. Flow discharge on the plots varied between 3 and 355 mm h⁻¹ and unit sediment yield varied between 0.02 and 30 g m⁻² min⁻¹. Sediment yield was best predicted by flow discharge for both rainfall and run-on treatments on all sites explaining 18% to 75% of its variability. There was statistically significant difference between two treatments. Rainfall treatment generated 2 to 44 times more sediment than run-on at the same discharge rate. We found no strong evidence of raindrop impact affecting overland flow velocity. Among 19 variables related to surface conditions a weak correlation was found between sediment yield and plant foliar cover, structure, and surface litter. However, there was no single best cover predictor common for all ecological sites tested.
Collapse and failure of ancient agricultural stone terraces: On-site geomorphic processes, pedogenic mechanisms, and soil quality
2019, Geoderma
Citation Excerpt :
Regardless, as expected, mean of soil penetration resistance was significantly and 75% greater in the inter-shrub spaces than that in the shrubby patches (Table 2). The significantly and over twofold greater electrical conductivity of soil in the shrubby patches than in the intershrub spaces (Table 2) is somewhat unexpected due to the assumed greater leaching capacity of salts under the shrub canopy (Stavi et al., 2009). A possible explanation for this finding could be the combined effect of: (1) washing of salts from the H. scoparium's shoots by processes of throughfall (Zhang et al., 2016) and stemflow (Wang et al., 2011), and their accumulation beneath the shrub canopy; (2) defoliation of the shrub's saline leaves and stems, and their accumulation under its canopy; and (3) adsorption of salts from runoff water by the organic residues which accumulate under the shrub canopy.
Water is the major limiting factor for primary productivity in drylands. In ancient times, stone terraces aimed at runoff harvesting and soil erosion control were established, allowing agricultural crop production. Land abandonment and cease of maintenance have led to the collapse and failure of terraces in the hinterlands of the Roman/Byzantine city of Avdat in the arid Negev Desert, Israel. The objective of this study was to assess the geomorphic processes and pedogenic mechanisms related to terrace collapse, and their on-site impact on soil quality. We studied key properties of the top 10 cm of soil in intact-terrace plots and partially-collapsed terrace plots, as well as in ‘natural’ lands. Unexpectedly, the soil texture was finer in the partially collapsed-terrace plots (clay loam) than that in the intact-terrace plots (loam). This was attributed to transportation of mineral material by rolling, which sorts out the large primary particles. This process, which characterizes rill erosion of high erosive power, is probably the predominant surface process in this study. The soil penetration resistance was significantly greater in the partially-collapsed terrace plots, and was attributed to the continuous removal of recently deposited loose sediments and exposure of the underlying, compacted older sediments. Soil stoniness, which was 16-fold greater in the partially-collapsed terrace plots, was also attributed to soil erosion. Unexpectedly, the total organic carbon was similar in both terrace states. Yet, labile organic carbon was 41% lower in soil of the partially-collapsed terrace plots, suggesting greater susceptibility of this fraction to erosional processes. The low electrical conductivity in the soil of the intact-terrace plots, was attributed to the better leaching of salts. The soil's calculated available water capacity was 42% greater in the intact-terrace plots. The study suggests that these processes and mechanisms strengthen each other through a chain of feedbacks, resulting in accelerated degradation of the collapsed-terrace lands.
Geodiversity effects on soil quality and geo-ecosystem functioning in drylands
2019, Catena
Geodiversity is defined as the natural variability of geologic, geomorphic, and soil features. It has been acknowledged to positively affect biodiversity and species richness. A long-term drought occurring in the semi-arid northern Negev of Israel has led to the mass mortality of shrubs, with the particularly adverse impact on the predominant Noaea mucronata species. Recent observations in these shrublands have suggested that this mass mortality is not uniformly distributed over the landscape, but is confined to hillslopes characterized by low-geodiversity. This type of hillslope is defined by a deep (>1 m) soil layer, lacking rock fragments in its profile and on its surface. Also, the herbaceous vegetation cover of these hillslopes is very high (>90%), but shrubby vegetation cover is very low (<10%) and for the most part, non-vital. At the same time, shrubby vegetation in high-geodiversity hillslopes – defined by a shallow (~10 cm) soil layer, and high rock fragment content (>30% volume) and cover (>20%) – is rather dense (>25%) and vital, but their herbaceous vegetation cover is quite sparse (<30%). Soil was sampled from the 0–10 cm depth in two micro-habitats – shrubby patches and inter-shrub spaces – on both the homogeneous and heterogeneous hillslopes. Overall, soil quality was found to be considerably higher in the heterogeneous hillslopes compared to the homogeneous hillslopes. This included the contents of hygroscopic moisture, total organic carbon, particulate organic carbon, and carbon lability, whose means were 22%, 36%, 27%, and 38%, respectively, greater in the heterogeneous hillslopes. Further, mean clay dispersion index was 18% lower in the heterogeneous hillslopes. At the same time, mean soil electrical conductivity was 13% greater in the heterogeneous hillslopes. Yet, this could be attributed to the greater clay content in the former type (19.1%) than that in the latter type (12.7%) of hillslope, with the assumingly higher salt-adsorption from the soil solution. Overall, the results show that the effect of micro-habitat on the soil properties was relatively moderate, and therefore, suggest that the impact of geodiversity might override that of vegetation patchiness. The results highlight the importance of assessing patch-scale and/or hillslope-scale geodiversity in future studies of dryland ecosystems around the world.
Small-Format Aerial Photography and UAS Imagery: Principles, Techniques and Geoscience Applications
2019, Small-Format Aerial Photography and UAS Imagery: Principles, Techniques and Geoscience Applications
Soil quality and aggregation in runoff water harvesting forestry systems in the semi-arid Israeli Negev
2016, Catena
Water availability is a major limiting factor for dryland afforestation. Earthworks that modify natural landforms for the formation of runoff harvesting systems are prevalent in the Israeli drylands, with the aim of establishing afforestation projects. However, serious concerns alarm that such earthworks have detrimental effects on the geo-ecosystem functioning. Therefore, the objective of this study was to examine the impact of the establishment of contour bench terrace (also called shichs/shychs/shikim) runoff harvesting systems on selected soil properties, with particular focus on soil aggregation. Thus, we assessed the effect of the establishment of contour bench terraces in a multi-aged forestry land, comprised of 2-year-old and 9-year-old afforestation areas, and compared them to ‘natural’ hillslopes as a reference treatment. The study was implemented in the Ambassadors' Forest, located in the semi-arid northern Negev of Israel, where we sampled the surface soil (at a depth of 0–5 cm) in north- and south-facing hillslopes. Considerable differences were recorded for the afforestation systems between the source (inter-terrace area) and sink (terrace-bottoms) areas. Data normalizing according to the relative cover percentage of the terraces and inter-terrace areas showed that the mean values of mean weight diameter (MWD), stable aggregate content, and particulate organic carbon in the natural hillslopes were 1.4%, 32.4%, and 20%, respectively, greater than in the 9-year-old afforestation systems, and 12.1%, 28.9%, and 31%, respectively, greater than in the 2-year-old systems. Means of clod content, aggregate slaking index, and clay dispersion index in the natural hillslopes were 62.3%, ~ twofold, and 35.0%, respectively, smaller than in the 9-year-old systems, and almost threefold, nearly twofold, and 46.2%, respectively, smaller than in the 2-year-old areas. The soil calcium carbonate content was similar in soils of the natural hillslopes and 9-year-old afforestation lands, which was ~ 17% smaller than in the 2-year-old afforestation systems. Considerable differences among the land-uses were also recorded for the soil texture. Mean coarse root biomass, despite revealing only a marginally-significant effect (p-value = 0.0765), was 40.0% greater in the natural hillslopes than in the 9-year-old systems, and more than twofold greater than in the 2-year-old systems. Hillslope aspect affected some of the measured properties, revealing only slightly better soil conditions in the (mesic) north- than in the (xeric) south-aspects. The data revealed that forestry-related earthworks degrade the soil quality and geo-ecosystem functioning in the short term. Yet, despite some discrepancies, the data also showed the occurrence of self-restoration processes of the geo-ecosystem over the long term.

View all citing articles on Scopus

View full text

Ecogeomorphic Feedbacks in Semiarid Rangelands: A Review

Abstract

J. Arid Environ.

Catena.

Catena.

Catena.

J. Hydrol.

J. Arid Environ.

Geomorphology.

Catena.

J. Arid Environ.

J. Arid Environ.

J. Arid Environ.

Catena.

J. Arid Environ.

Geomorphology.

J. Arid Environ.

Catena.

J. Arid Environ.

B. Math. Biol.

Soil Biol. Biochem.

Catena.

Catena.

J. Arid Environ.

J. Arid Environ.

J. Arid Environ.

Geomorphology.

J. Arid Environ.

J. Arid Environ.

Catena.

Geomorphology.

J. Arid Environ.

Geoderma.

J. Arid Environ.

Geomorphology.

Catena.

Geomorphology.

J. Arid Environ.

Catena.

J. Arid Environ.

J. Arid Environ.

Physica A.

Soil Biol. Biochem.

Association between plant canopies and the spatial patterns of infiltration in shrubland and grassland of the Chihuahuan desert, New Mexico

Ecosystems.

Effect of soil surface sealing on splash from a single waterdrop

Soil Sci. Soc. Am. J.

Overstory-imposed heterogeneity in solar radiation and soil moisture in a semiarid woodland

Ecol. Appl.