Some ecological side-effects of chemical and physical bush clearing in a southern African rangeland ecosystem

Haussmann, Natalie S.; Kalwij, Jesse M.; Bezuidenhout, Stefan

doi:10.1016/j.sajb.2015.07.012

Cited by 13 publications

(5 citation statements)

References 25 publications

(36 reference statements)

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“…Field observation also revealed extensive bush clearing but with low recruitment of desirable pasture species and high dominance of herbaceous weedy species that seemed to demoralize adopters. The observed bush encroachment and farmer"s effort to clear them support observations made by Haussmann et al (2016) who noted ecological consequences associated with physical clearing, especially when the topsoil is disturbed and habitat structure is altered that ultimately favor the growth of perennial grass species as well as re-establishment of fast-growing, undesired species. Bush encroachment and water scarcity were major challenges affecting rangeland productivity and livelihoods to the extent that they take priority for agro pastoralist investment thus the high adoption rates recorded in this study.…”

Section: Agro-pastoralists' Adoption Of Range Pasture Improvement Andsupporting

confidence: 81%

Drivers and restrictions of range pasture improvement by agro-pastoralists in Kiruhura District, Uganda

Robert¹,

Sarah²,

Okello³

2020

Afr. J. Agric. Res.

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Range pastures provide the basic ruminant feeds resource for livestock production in semi-arid areas despite ruminant nutrition remaining a challenge affecting productivity. Different livestock development interventions have been promoted to improve livestock nutrition with low farmer adoption rate. A cross sectional exploratory study was conducted between March and July 2018 to identify the drivers of range pastures improvement technologies adoption in rangelands with specific objectives as: (a) Assessing the knowledge, attitudes and practices of pastoralists in regard to range pasture improvement practices and technologies; (b) identifying the forage species planted by pastoralists and strategies for their sustainable utilization; (c) identifying the incentives for the adoption and maintenance of range pasture improvement practices and; (d) identifying the key players and their roles in range pasture improvement promotion and constraints faced in attempt to improve rangeland pastures. A structured questionnaire guided interview was conducted with 294 agro pastoralists while qualitative data was obtained using, KII. Results revealed that farmers had knowledge on range pasture improvement technologies, although adoption rate was low (19.5%). The range pasture improvement practices, included: Pasture establishment, bush clearing, paddocking, conservation, reseeding and over-sowing and water development. However, results also revealed knowledge gaps in silage and hay making, reseeding and understanding principles of range management. The level of education, household income, off farm activities, access to laborers and credit, agriculture exhibitions, farmers' meetings and on-farm demonstrations influenced farmers' adoption of fodder production technologies. Farm gate milk prices, sensitization, financial support, farm output of adopters and inputs support seemed to drive farmers to improve their range pastures. These findings underline the importance of farm-gate milk prices and institutional support as drivers for farmer decision for investment in pasture improvement. Therefore, policy and development interventions should emphasize improvement of milk farm gate prices and farm support systems.

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Section: Agro-pastoralists' Adoption Of Range Pasture Improvement Andsupporting

confidence: 81%

Drivers and restrictions of range pasture improvement by agro-pastoralists in Kiruhura District, Uganda

Robert¹,

Sarah²,

Okello³

2020

Afr. J. Agric. Res.

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“…Already bush‐encroached areas are often mechanically cleared. However, every manipulation of ecosystems results in changes of the habitat with subsequent impacts on vegetation and faunal composition (Cogger & Cogger, ; Haussmann et al., ), including changes in habitat use or in animal movements (Archibald et al., ). In this matter, knowledge about the influence of bush clearing on large herbivores is of interest, as the changes in natural herbivore assemblage are described as one driver of bush encroachment (Staver et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…() developed an expert system for arid rangeland management that includes several procedures to prevent bush encroachment, for example the monitoring of seed production. Also herbicides and fires are used for management (but see Haussmann, Kalwij, & Bezuidenhout, ; Angassa & Oba, ; Joubert, Smit, & Hoffman, ; Lohmann, Tietjen, Blaum, Joubert, & Jeltsch, ; Mudongo, Fynn, & Bonyongo, ). However, for practical and economic reasons the mechanical removal of woody plants is often used as management strategy for promoting natural grass growth or restoring bush‐encroached savannahs by reseeding with perennial grasses (Smit, ).…”

Section: Introductionmentioning

confidence: 99%

Influence of differently managed bush‐encroached sites on the large herbivore distribution in the Namibian Savannah

2017

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Bush encroachment is reported from savannah regions worldwide. Different management strategies are used to rehabilitate these areas. In this context, the mutual interaction between vegetation and large herbivore's distribution is evident. We studied effects of land management on vegetation structure in regard to encroaching species and the subsequent habitat use of two grazing (oryx, Oryx gazella L.; common warthog, Phacochoerus africanus GMELIN) and one browsing (greater kudu, Tragelaphus strepsiceros PALLAS) herbivore species. We assumed that (i) cleared areas will be favoured by grazers and (ii) noncleared areas will be favoured by browsers.Specifically, we asked: Which factors determine the habitat use of these different feeding guilds? Consistently with our expectations, we found that warthog favoured sites with high grass cover. For oryx, surprisingly shrubs with a height of 80-150 cm influenced their distribution positively, whereas for kudu, only the interactivement leur distribution, alors que pour les koudous, seule l'interaction du site

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“…Every manipulation of ecosystems results in changes of the habitat with effects on vegetation composition and subsequent consequences for habitat use and movements of animals (e.g., Archibald et al, 2005;Haussmann et al, 2016). Changes in the natural herbivore composition are ascribed as one driver of the development of bush encroachment (e.g., Staver et al, 2009).…”

Section: Synthesis and Outlookmentioning

confidence: 99%

Impact of bush encroachment management on plant response and animal distribution

Stolter¹,

Joubert²,

Schwarz³

et al. 2018

Biodivers. Ecol.

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Abstract:The transformation of grassland by bush encroachment causes socioeconomic problems in arid and semi-arid regions. At the moment, de-bushing is the only way to control bush encroachment. In this context, we conducted two independent projects within SASSCAL. First, in a greenhouse experiment, we investigated the morphological plant response to damage of four diff erent bush encroacher species in order to understand if intervention in the plants' early life stage may reasonably fi ght bush encroachment and if treated plants are used diff erently by livestock (e.g., sheep and goats). In a second project, we investigated the infl uence of bush clearing on the habitat utilisation of diff erent large herbivores (e.g., greater kudu, warthog, and gemsbok). Specifi cally, we wanted to know if typical grazers (e.g., warthog and gemsbok) are found at open cleared sites and typical browsers (greater kudu) in encroached regions and if vegetation parameters (e.g., grass cover) drive this distribution. For our greenhouse experiment, we found that all seedlings reacted morphologically to the damage of top-shoots, but to diff erent extents. Damaged plants show species-specifi c responses, like diff erences in branching and thorn sizes and survival rates. In contrast to sheep, goats were not absolutely deterred by mechanical defences of the off ered plant species. Therefore, we assume that under controlled grazing regimes, goat feeding could be a useful tool to interfere with the establishment of large numbers of seedlings. In our second project, the animal distribution did not consistently match our expectations. While warthog and cattle shared open bush-cleared sites, we found gemsbok utilising non-cleared sites with high thornbush cover of medium height, which was similar to patterns shown by greater kudu. The results are discussed in light of competition, risk avoidance, and habitat heterogeneity.Resumo: A transformação dos prados pela densifi cação de plantas lenhosas causa problemas s ocioeconómicos em regiões áridas e semi-áridas. De momento, a remoção de plantas lenhosas é a única maneira de controlar a sua densifi cação. Assim, conduzimos dois projectos independentes no contexto do SASSCAL. Numa experiência numa estufa, investigámos a resposta morfológica a danos de quatro espécies invasoras diferentes, de modo a compreender se a intervenção no estádio inicial de vida é razoável para combater a invasão das lenhosas, bem como se estas plantas tratadas são usadas de forma diferente pelo gado (ovelhas e cabras). Num segundo projecto, investigámos a infl uência do desmatamento na utilização do habitat por diferentes grandes herbívoros (cudo, javali-africano e órix). Especifi camente, queriamos saber se típicos herbívoros de pasto (e.x.: javali-africano e órix) eram encontrados em locais abertos, e típicos browsers (cudo) em regiões invadidas, e se os parâmetros da vegetação (e.x.: cobertura de gramíneas) conduzem esta distribuição. Na nossa experiência na estufa, descobrimos que todas as plântulas reagiram morfologic...

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Some ecological side-effects of chemical and physical bush clearing in a southern African rangeland ecosystem

Cited by 13 publications

References 25 publications

Drivers and restrictions of range pasture improvement by agro-pastoralists in Kiruhura District, Uganda

Drivers and restrictions of range pasture improvement by agro-pastoralists in Kiruhura District, Uganda

Influence of differently managed bush‐encroached sites on the large herbivore distribution in the Namibian Savannah

Impact of bush encroachment management on plant response and animal distribution

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