Land degradation in Mhondoro (Zimbabwe) : an environmental assessment of communal land uses and resource management practice

Thesis (MA)--Stellenbosch University, 2002.

ENGLISH ABSTRACT: When land loses its intrinsic qualities or suffers a decline in its capabilities it is said to be degraded. Land degradation manifests itself in various forms such as deforestation, soil erosion, land, air and water pollution. In the context of sustainable development land degradation has become one of the world's major concerns. Now, more than ever before, it has become urgent to carry out empirical studies on the nature and extent of land degradation and to come up with appropriate responses to the problem. In much of the developing world communal natural resource management practices are common. It is often assumed that communal exploitation of common property resources such as woodlands, pastures, water sources and wildlife inevitably leads to land degradation. This is due to the belief that humankind would seek to derive maximum benefit from common pool resources without incurring any costs towards the conservation of those resources. This study was an environmental assessment of the impacts of communal land-use systems and common property resources management practices in the Mhondoro communal lands of Zimbabwe. The area has been subject to human settlement for over a century and is regarded as a typical representation of a well-established communal land management system. Several methods were used to make the assessment. These included the following: a questionnaire survey; interviews with key informants; soil and vegetation traverses and field measurements; tree density counts in demarcated plots; calculation of the population density and livestock density for the study area; completion of an environmental evaluation matrix and a communal projects sustainability index checklist; and analysis of geo-referenced time-lapse aerial photography covering a fifteen year period (1982-1997). It was established that serious land degradation had occurred in Chief Mashayamombe's ward in Mhondoro. Degradation manifested itself in the form of soil erosion and stream sedimentation, woodland depletion, pasture degradation and wildlife habitat destruction. Communal land-use and natural resource management practices are only partially to blame for this state of affairs. The fragile nature of the sandy soils of the uplands, the sadie soils of the vlei areas, combined with the fairly high rainfall amounts (annual average 750mm) make the area prone to soil erosion. Rainfall intensity tends to be high in the area and when the rain falls on the poorly vegetated, and highly erodible soils erosion occurs. The land has become severely stressed due to over-utilisation; a population density of 93 people per km2 and livestock density of 110 cattle per km2 were recorded. The land available for communal settlement in the area has been limited in extent. Due to the general poverty of the communal farmers the replacement of nutrients into the cultivated soil has not kept pace with the deteriorating condition of the land. Contrary to popular misconceptions, communal area residents have shown concern for environmental conservation through fallowing their fields, gully reclamation efforts, grazing schemes, woodland preservation and tree growing practices. Remedial and/or mitigatory measures for the environmental recovery of the area could adopt some of these well-established practices and incorporate them in a whole-catchment management strategy. Key words Land degradation, environmental degradation, pollution, environmental assessment, common property resources, communal land uses, sustainable resources management, sustainability indicators, soil erodibility, soil erosivity

AFRIKAANSE OPSOMMING: Wanneer grond sy intrinsieke waarde verloor of 'n afname in sy vermoë toon, kan gesê word dat die grond gedegradeer is. Gronddegradasie manifesteer in verskeie vorme, soos ontbossing, gronderosie, grond, lug en water besoedeling. Gronddegradasie het binne die konteks van volhoubare ontwikkeling wêreldwyd van besondere belang geword. Nou, meer as ooit vantevore, is dit noodsaaklik om empiriese studies uit te voer aangaande die aard en omvang van gronddegradasie, en om vorendag te kom met toepaslike reaksies tot die probleem. Gemeenskaps natuurlike hulpbron bestuur praktyke is algemeen in die ontwikkelende wêreld. Daar word dikwels veronderstel dat uitbuiting van gemeenskaplike eiendoms hulpbronne deur die gemeenskap, soos woude, weivelde, waterbronne en wild, onvermeidelik lei na gronddegradasie. Hierdie aanname het ontwikkel as gevolg van die oortuiging dat die mensdom daarna sal streef om maksimum voordeel te trek uit gemeenskaplike hulpbronne, sonder om enige koste aan te gaan ten opsigte van die bewaring daarvan. Hierdie studie behels 'n omgewings evaluering van die impakte van gemeenskaps grondgebruik sisteme en gemeenskaplike eiendoms hulpbron bestuur praktyke in die Mhondoro gemeenskaplike grond van Zimbabwe. Die area word al vir meer as 'n eeu deur mense bewoon, en word beskou as 'n tipiese voorbeeld van 'n gevestigde gemeenskaps grondbestuur sisteem. Verskeie metodes is toegepas met die evaluering, en sluit in: 'n vraelys opname; onderhoude met sleutel segspersone; grond en plantegroei opnames en veldopnames; boom digtheidstelling in afgebakende persele; berekening van bevolkingsen veedigtheid vir die studiegebied; opstelling van 'n omgewing evaluerings matriks en 'n gemeenskap projek volhoubaarheids indeks kontroleerlys; en 'n analise van geo-referenced time-lapse lugfoto's wat strek oor 'n tydperk van 15 jaar (1982-1997). Daar is vasgestel dat ernstige gronddegradasie voorkom in Hoofman Mashayamombe se wyk in Mhondoro. Degradasie word gemanifesteer in die vorm van gronderosie en stroom sedimentasie, uitputting van woude, weiveld degradasie en die verwoesting van wild habitatte. Gemeenskaps grondgebruik en natuurlike hulpbron bestuurspraktyke is net gedeeltelik verantwoordelik vir die stand van sake. Gronderosie vind plaas ook as gevolg van die sensitiewe aard van die sanderige grond van die hoogland, die sodic grond van die vlei areas, in kombinasie met redelike hoë reënval (gemiddeld 750mm per jaar). Reënval intensiteit in die area is geneig om hoog te wees, en erosie vind plaas wanneer reën val op die hoogs erodeerbare grond wat met yl plantegroei bedek is. Die grond verkeer onder geweldige druk as gevolg van oorbenutting; 'n bevolkingsdigtheid van 93 mense per km2 en veedigtheid van 110beeste per km2 is aangeteken. Die grond beskikbaar vir vestiging van gemeenskappe word in omvang beperk. Die vervanging van grondvoedingstowwe in bewerkte grond hou nie tred met die agteruitgang in die kondisie van die grond nie, as gevolg van die algemene armoede van die gemeenskapsboere. Inwoners van die gemeenskapsarea , teenstrydig met algemene wanopvattings, toon besorgdheid ten opsigte van omgewingsbewaring deur die grond braak te lê, donga herwinnings pogings, wei velds planne, bewaring van woude en praktyke ten opsigte van die groei van bome. Remediërende en/of versagtende maatstawwe vir die herstel van die omgewing kan van hierdie gevestigde praktyke inkorporeer in 'n bestuursstrategie wat die hele opvangsgebied insluit. Sleutelwoorde Gronddegradasi e, omgewingsde gradasi e, besoedeling, omgewingsassessering, gemeenskaplike eiendoms hulpbronne, gemeenskaplike grondgebruik, volhoubare hulpbron bestuur, volhoubaarheids aanwysers, grond erodeerbaarheid, grond verwering.

Masters