Causes and consequences of fenceline contrasts in Namibian rangeland
| dc.contributor.advisor | Smit, G. N. | |
| dc.contributor.author | Zimmermann, Ibo | |
| dc.date.accessioned | 2016-01-08T09:37:07Z | |
| dc.date.available | 2016-01-08T09:37:07Z | |
| dc.date.copyright | 2009-08-31 | |
| dc.date.issued | 2011-02-15 | |
| dc.date.submitted | 2009-08-31 | |
| dc.description.abstract | English: This study made use of the opportunity provided by fenceline contrasts in Namibia to measure differences in rangeland and learn from farmers about the inputs and outputs of management on each side of the fence. The 34 measured contrasts were mostly clustered within the Camelthorn and Thornbush Savannas, with three in the Highland and Dwarf shrub Savannas of Namibia. Mean annual rainfall ranges from 235 to 475 mm. Rangeland measurements focussed on well established perennial vegetation to avoid the fluctuating effect of ephemerals. Eight characteristics were measured and significant (P<0.05) differences occurred in at least one of these at each contrast. Two characteristics (distance from sample point to the nearest perennial grass and the species) were combined to determine a rangeland condition index. At 22 of the 34 contrasts the condition index was significantly (P<0.05) higher on one side of the fence. There was no clear method to distinguish between the influences of different management inputs that may have caused the fenceline contrasts. Therefore, subjective judgment was relied upon to identify bush control as the most likely single causative factor at ten contrasts, stocking rate and period of rest at five contrasts each, and stocking density at two contrasts. Management contributed to both causes and consequences of fenceline contrasts. The negative correlation between stocking rate and rangeland condition index was weak (r = −0.2575, P = 0.04, n = 64), suggesting that there may have been more farms where a higher stocking rate was the cause of poorer rangeland than farms where the higher stocking rate was the consequence of better rangeland raising the carrying capacity. The stronger correlation between profit and income (r = 0.9288, P < 0.001, n = 25) than between profit and expenditure (r = 0.0267, P = 0.899, n = 25), suggests that farmers should focus on reducing non-essential expenditure to increase profitability. Game farming can earn high income, but continuous selective grazing by gregarious game animals may lead to poorer rangeland condition. Useful lessons were learnt from the case study of an innovative farmer who adapted his management based upon his keen observations of rangeland dynamics. Many of his interventions were strategically timed in relation to rainfall events. There is much that can be learnt by both scientists and other farmers from the management strategies applied by successful farmers who earn a good profit while sustaining the rangeland. | en_ZA |
| dc.description.abstract | Afrikaans: Hierdie studie het die geleentheid wat deur grensdraad kontraste in Namibië moontlik gemaak is gebruik om veranderinge in plantegroei beide kante van die grensdraad te meet en om kennis in te win van boere omtrent die bestuursinsette- en uitsette aan beide kante van die grensdaad. Die 34 gemete kontraste was meestal binne die kameeldoring en doringbos savanna van Namibië geleë, met drie in die Hoogland savanna en dwerg bossie savanna. Gemiddelde jaarlikse reënval het gewissel van 235 – 475 mm. Plantegroei metings het gefokus op gevestigde meerjarige plante ten einde die wisselvalligheid van eenjarige plante te vermy. Agt veranderlikes is gemeet en betekenisvolle (P<0.05) verskille in ten minste een veranderlike is by elke kontras gevind. Twee veranderlikes (afstand vanaf metingspunt na die naaste meerjarige gras, asook die spesie) is gekombineer om ‘n veldtoestands indeks te bereken. By 22 van die 34 kontraste was die veldtoestand betekenisvol (P< 0.05) hoër aan die een kant van die grensdraad in vergelyking met die ander kant. Daar was geen geskikte metode om tussen die bydraes van verskillende bestuursinsette wat moontlike tot die grensdraad kontraste aanleiding gee het, te onderskei nie. Om hierdie rede was dit nodig om op subjektiewe beoordeling te vertrou waarvolgens ontbossing geidentifiseer is as die mees waarskynlike veranderlike wat by 10 kontraste tot die meeste verskille bygedra het. By ‘n verdere vyf kontraste is veelading en rus as die belangrikste veranderlikes geïdentifiseer en veedigtheid by nog twee kontraste. Bestuur het bygedra tot beide die oorsake en gevolge van die grensdraad kontraste. Die negatiewe korrelasie tussen veelading en veldtoestands indeks was swak (r = −0.2575, P = 0.04, n = 64). Hieruit wil dit voorkom of daar meer plase was waar ‘n hoë veelading die oorsaak van swak weiding was teenoor plase waar die hoër veelading die gevolg was van beter weiding wat die weidingkapasiteit verhoog het. Die sterker korrelasie tussen wins en inkomste (r = 0.9288, P<0.001, n = 25) as tussen wins en uitgawes (r = 0.0267, P = 0.8999) n = 25), is ‘n aanduiding dat boere op die vermindering van nie noodsaaklike uitgawes moet konsentreer ten einde winsgewendheid te verhoog. Wildboere kan ‘n hoër inkomste verdien, maar aanhoudende, selektiewe beweiding deur wildtroppe mag tot swakker weidingtoestande lei. Uit die gevallestudie van ‘n innoverende boer wat sy bestuur op fyn waarnemings van weiveld dinamika gebaseer het, is waardevolle lesse geleer. Talle van sy bestuursintervensies was met strategiese tydsberekening ten opsigte van reënval toestande geneem. Daar is baie wat deur beide navorsers en mede boere van die bestuurstrategië van suksesvolle boere wat ‘n redelike wins toon en wie hul weiding in ‘n goeie toestand hou, geleer kan word. | af |
| dc.identifier.uri | http://hdl.handle.net/11660/2071 | |
| dc.language.iso | en | en_ZA |
| dc.publisher | University of the Free State | en_ZA |
| dc.rights.holder | University of the Free State | en_ZA |
| dc.subject | Thesis (Ph.D. (Animal, Wildlife and Grassland Sciences))--University of the Free State, 2009 | en_ZA |
| dc.subject | Range management -- Namibia | en_ZA |
| dc.subject | Growth (Plants) -- Measurement | en_ZA |
| dc.subject | Shifting cultivation | en_ZA |
| dc.subject | Savanna | en_ZA |
| dc.subject | Biodiversity | en_ZA |
| dc.subject | Bush encroachment | en_ZA |
| dc.subject | Fenceline contrasts | en_ZA |
| dc.subject | Rangeland condition | en_ZA |
| dc.subject | Rangeland management | en_ZA |
| dc.subject | Savanna | en_ZA |
| dc.subject | Stocking rate | en_ZA |
| dc.title | Causes and consequences of fenceline contrasts in Namibian rangeland | en_ZA |
| dc.type | Thesis | en_ZA |