Restoring productive rangelands: A comparative assessment of selective and non-selective chemical bush control in a semi-arid Kalahari savanna

Harmse, Christiaan J.; Kellner, Klaus; Dreber, Niels

doi:10.1016/j.jaridenv.2016.08.009

Cited by 24 publications

(40 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Chemicals such as Tordon 225 and tebuthiuron have been successfully used, but the use of Tordon 225 is restricted by certain physiological and environmental conditions [30]. Concerns about tebuthiuron on the other hand pertain to the accumulation and persistence of the chemical in the soil thus posing potential threats to non-target species [36,37]. Biological methods sometimes employed include the controlled use of herbivores (especially goats) and fire.…”

Section: Combating Bush Encroachmentmentioning

confidence: 99%

Vachellia (Acacia) karroo Communities in South Africa: An Overview

Dingaan¹,

Preez²

2018

Pure and Applied Biogeography

View full text Add to dashboard Cite

Vachellia karroo is a useful and widespread tree in Africa. It belongs to the family Fabaceae, which is the third largest woody plant family in southern Africa. This is an ecologically and economically important species as almost all of its parts, including bark, pods, seeds, leaves and thorns, are extremely useful to both humans and animals. Various commercial products are also obtained from the tree, and gum is one of the most important products. V. karroo in South Africa has an extensive distribution range that includes several biomes. It is very adaptable and has wide habitat tolerance, growing under many differing conditions of soil, climate, and altitude. Although it is often associated with heavy, clayey soils on the banks of rivers and streams, it also grows in bushveld, dry thornveld, grassland and woodland. V. karroo is easy to grow and as a result can become an aggressive invader of valuable farming land and grazing areas, a phenomenon usually referred to as bush encroachment. An analysis of historic data comprising 1553 relevés and 2006 species, compiled from all areas of South Africa where V. karroo is known to occur was conducted, and TWINSPAN classification produced five main vegetation types.

show abstract

Section: Combating Bush Encroachmentmentioning

confidence: 99%

Vachellia (Acacia) karroo Communities in South Africa: An Overview

Dingaan¹,

Preez²

2018

Pure and Applied Biogeography

View full text Add to dashboard Cite

show abstract

“…In recent years many pastoralists from countries in southern Africa started to apply a wide range of management practices to counteract shrub-encroachment, for example, prescribed fires, chemical or manual bush control, brush packing and reseeding of perennial grasses. It is still not clear which of these practices are successful under which farming system and environmental conditions (Harmse, Kellner, & Dreber, 2016;Throop & Archer, 2007;van den Berg & Kellner, 2005).…”

mentioning

confidence: 99%

Interconnected effects of shrubs, invertebrate‐derived macropores and soil texture on water infiltration in a semi‐arid savanna rangeland

et al. 2020

View full text Add to dashboard Cite

Many semi arid savannas are prone to degradation, caused for example, by overgrazing or extreme climatic events, which often lead to shrub encroachment. Overgrazing by livestock affects vegetation and infiltration processes by directly altering plant composition (selective grazing) or by impacting soil physical properties (trampling). Water infiltration is controlled by several parameters, such as macropores (created by soil-burrowing animals or plant roots) and soil texture, but their effects have mostly been studied in isolation. Here we report on a study, in which we conducted infiltration experiments to analyze the interconnected effects of invertebrate-created macropores, shrubs and soil texture (sandy soil and loamy sand) on infiltration in two Namibian rangelands. Using structural equation modeling, we found a direct positive effect of shrub size on infiltration and indirectly via invertebrate macropores on both soil types. On loamy sands this effect was even stronger, but additionally, invertebrate-created macropores became relevant as a direct driver of infiltration. Our results provide new insights into the effects of vegetation and invertebrates on infiltration under different soil textures. Pastoralists should use management strategies that maintain a heterogeneous plant community that supports soil fauna to sustain healthy soil water dynamics, particularly on soils with higher loam content. Understanding the fundamental functioning of soil water dynamics in drylands is critical because these ecosystems are water-limited and support the livelihoods of many cultures worldwide.

show abstract

“… Bush control refers to past applications (minimum 6 years old) of a tebuthiuron‐based arboricide in areas, where the density of the woody layer most likely exceeded 1.000 tree equivalents per ha (1 TE = woody plant of 1.5 m). In untreated sites, an ongoing preventative range management maintained a moderate bush cover over time, whereas the combined effect of overgrazing and suppression of wildfires was the likely cause for the thickening of vegetation in the high‐bush cover sites (Harmse, Kellner & Dreber, ). …”

Section: Methodsmentioning

confidence: 99%

“…The implications for ecosystem functions are varied, whereas negative effects on key services such as forage production are among the most prevalent. Hence, active bush control is often applied by local commercial farmers to thin out the woody layer and restore the economic viability of their rangelands (Harmse, Kellner & Dreber, ). A positive ecological side effect of such measures can be the conservation of local biodiversity, whose overall status may otherwise significantly decline in response to compositional and structural changes of thickening woody vegetation (Archer & Predick, ).…”

Section: Introductionmentioning

confidence: 99%