Restoration thinning reduces bush encroachment on freehold farmlands in north-central Namibia. (27th March 2021)
- Record Type:
- Journal Article
- Title:
- Restoration thinning reduces bush encroachment on freehold farmlands in north-central Namibia. (27th March 2021)
- Main Title:
- Restoration thinning reduces bush encroachment on freehold farmlands in north-central Namibia
- Authors:
- Nghikembua, Matti T
Marker, Laurie L
Brewer, Bruce
Leinonen, Arvo
Mehtätalo, Lauri
Appiah, Mark
Pappinen, Ari - Abstract:
- Abstract: Bush encroachment affects ~45 million ha of Namibia and, without appropriate restoration measures, it negatively affects rangeland productivity and biodiversity. Thinning is a common method to counteract bush encroachment. The thinning strategy applied in north-central Namibia was assessed to examine how effective it has been in reducing bush encroachment. Trees/shrubs were selectively thinned manually, targeting all height classes, except individuals with stem diameters ≥18 cm. We investigated the effects on the vegetation and soil properties using surveys on three freehold farms (in 2016 and 2017) in bush-encroached and previously thinned habitats. Our results revealed significant differences in the mean total nitrogen (TN) content between the treatments; thinned areas had higher TN content which would be beneficial for fast-growing grasses. In the thinned plots, the occurrence probability of red umbrella thorn ( Vachellia reficiens Warwa) was significantly reduced, indicating that it was the most harvested species; and umbrella thorn ( Vachellia tortilis (Burch.) Brenan spp. heteracantha ) was increased, indicating that it favoured reduced densities of dominant species. Natural regeneration was rapid; the tree/shrub abundance in the 0–1-m height class in the thinned area surpassed those in the non-thinned by 34 per cent, ~7.2 years since thinning. Thinning significantly reduced tree/shrub abundances of the 1–3- and >3-m height classes, which was still evidentAbstract: Bush encroachment affects ~45 million ha of Namibia and, without appropriate restoration measures, it negatively affects rangeland productivity and biodiversity. Thinning is a common method to counteract bush encroachment. The thinning strategy applied in north-central Namibia was assessed to examine how effective it has been in reducing bush encroachment. Trees/shrubs were selectively thinned manually, targeting all height classes, except individuals with stem diameters ≥18 cm. We investigated the effects on the vegetation and soil properties using surveys on three freehold farms (in 2016 and 2017) in bush-encroached and previously thinned habitats. Our results revealed significant differences in the mean total nitrogen (TN) content between the treatments; thinned areas had higher TN content which would be beneficial for fast-growing grasses. In the thinned plots, the occurrence probability of red umbrella thorn ( Vachellia reficiens Warwa) was significantly reduced, indicating that it was the most harvested species; and umbrella thorn ( Vachellia tortilis (Burch.) Brenan spp. heteracantha ) was increased, indicating that it favoured reduced densities of dominant species. Natural regeneration was rapid; the tree/shrub abundance in the 0–1-m height class in the thinned area surpassed those in the non-thinned by 34 per cent, ~7.2 years since thinning. Thinning significantly reduced tree/shrub abundances of the 1–3- and >3-m height classes, which was still evident 7.2 years since thinning. Based upon the generalized linear mixed-effects model, tree/shrub counts between treatments may equalize in ~14 and 15 years for the 1–3- and >3-m height classes, respectively. Thinning was effective in reducing tree/shrub abundances and can be used to restore wildlife habitat on the Namibian farmland: however, post-thinning management is required to maintain an open savannah vegetation structure as the 0–1-m height class cohort will eventually grow into mature trees/shrubs. … (more)
- Is Part Of:
- Forestry. Volume 94:Number 4(2021)
- Journal:
- Forestry
- Issue:
- Volume 94:Number 4(2021)
- Issue Display:
- Volume 94, Issue 4 (2021)
- Year:
- 2021
- Volume:
- 94
- Issue:
- 4
- Issue Sort Value:
- 2021-0094-0004-0000
- Page Start:
- 551
- Page End:
- 564
- Publication Date:
- 2021-03-27
- Subjects:
- Forests and forestry -- Periodicals
Forests and forestry -- Great Britain -- Periodicals
634.9 - Journal URLs:
- http://forestry.oxfordjournals.org/ ↗
http://ukcatalogue.oup.com/ ↗ - DOI:
- 10.1093/forestry/cpab009 ↗
- Languages:
- English
- ISSNs:
- 0015-752X
- Deposit Type:
- Legaldeposit
- View Content:
- Available online (eLD content is only available in our Reading Rooms) ↗
- Physical Locations:
- British Library DSC - 4000.000000
British Library DSC - BLDSS-3PM
British Library HMNTS - ELD Digital store - Ingest File:
- 18422.xml