No abstract

The increase in biomass and abundance of woody plant species, often thorny or unpalatable, coupled with the suppression of herbaceous plant cover, is a widely recognized form of rangeland degradation. Bush encroachment therefore has the potential to compromise rural livelihoods in Africa, as many depend on the natural resource base. The causes of bush encroachment are not without debate, but fire, herbivory, nutrient availability and rainfall patterns have been shown to be the key determinants of savanna vegetation structure and composition. In this paper, these determinants are discussed, with particular reference to arid and semi-arid environments of Africa. To improve our current understanding of causes of bush encroachment, an integrated approach, involving ecological and indigenous knowledge systems, is proposed. Only through our knowledge of causes of bush encroachment, both direct and indirect, can better livelihood adjustments be made, or control measures and restoration of savanna ecosystem functioning be realized. ResumenUna forma ampliamente reconocida de degradación de pasturas es el incremento de la abundancia de especies de plantas leñosas, a menudo espinosas y no palatables, y de su biomasa, conjuntamente con la pérdida de plantas herbáceas. En África, la invasión por arbustos puede comprometer el sistema de vida rural ya que muchas personas dependen de los recursos naturales básicos. Las causas de la invasión por arbustos no están lo suficientemente claras pero el fuego, los herbívoros, la disponibilidad de nutrientes y el patrón de precipitación han demostrado ser determinantes clave de la estructura y la composición de la vegetación de sabana. En este documento se hace un análisis del impacto de estos determinantes, con especial referencia a los ambientes áridos y semi-áridos de África. Para una mejor comprensión de las causas de la invasión por arbustos se propone un enfoque integrado que involucra sistemas ecológicos y de conocimiento autóctono. Solamente a través del conocimiento, tanto directo como indirecto, de las causas de la invasión por arbustos, será posible hacer los ajustes necesarios para una mejor calidad de vida o tomar las medidas de control y restauración de las funciones del ecosistema de sabanas.

Despite their importance to rural livelihoods, the economic and environmental sustainability of contemporary communal pastoral systems of the Kalahari is increasingly being put under scrutiny. Using data collected from a survey of randomly selected pastoral households from two districts of Ghanzi and Kgalagadi South, Botswana, this paper outlines the major constraints affecting contemporary extensive pastoral systems. Because of the prevailing semi-arid climate, recurrent drought outbreaks were cited as a common challenge in both study areas together with lack of fenced grazing areas. Stock theft was also highlighted as a challenge, even though it was more pronounced in Kgalagadi South. In Ghanzi area, the other important challenges included loss of livestock due to predation, while stray animals, stock theft and loss of livestock due to road accidents were equally important. Kgalagadi South pastoral households experienced serious shortage of drinking water for their livestock, followed by inadequate grazing land and limited access to distant markets. The preceding, together with several other less prominent challenges revealed in this study, exert pressure on pastoral livelihoods. There is need, therefore, to address these perceived challenges and strengthen resilience through effective policy reviews to secure rural livelihoods.

No abstract

Current efforts to control and possibly eradicate the highly contagious and economically important Foot and Mouth disease (FMD) in Botswana are hampered by numerous inextricably linked constraints. These constraints were unveiled using a questionnaire-based approach among 94 communal area livestock owners in eastern Botswana's Zone 6 (FMD-free zone without vaccination, straddling part of the Central and North East Districts, sharing a common border with Zimbabwe to the east). The area has a history of FMD, with the last outbreaks recorded in 2002 and 2003 prior to the study. Some of the most outstanding constraints in FMD control were (1) rampant cross-border livestock theft, (2) veterinary cordon fence damage attributed to illegal immigrants and an ever-increasing elephant population, (3) livestock interaction with FMD-susceptible wild ungulates on the same rangelands, and (4) an absence of a protection zone (formerly 'buffer zone') along the Botswana/Zimbabwean border as well as (5) general apathy towards daily livestock management demonstrated by some owners/herders. The paper further discusses these complex socioecological constraints as perceived by livestock owners and offers possible policy considerations including targeted FMD awareness campaigns, strengthening of FMD risk analysis capacity and synchronization of surveillance and control strategies among neighbouring countries as well as adoption of approaches such as compartmentalization and commodity-based trade to enable greater access of Botswana's beef to high-value international markets.