In arid and semi-arid environments, pastoralists use herd mobility to manage resource variability. We investigated temporal mobility patterns of livestock keepers on the spatially confined commons of Namaqualand, South Africa, between 1997 and 2006. We conducted semi-structured interviews with about 300 livestock keepers from ten villages in the Leliefontein communal area. Herd mobility varies significantly amongst the herds in the different villages. Mobility in Leliefontein is complex and is influenced by environmental, agricultural, social and personal factors. We conclude that even with a high degree of variability in herd movements, the mobility patterns of livestock keepers over the last ten years have remained relatively stable.

The potential of Cephalophyllum inaequale was investigated for use in initiating ecosystem restoration in degraded landscapes of Namaqualand, South Africa. Cephalophyllum inaequale, a perennial shrub, is a member of the succulent Mesembryanthemaceae family, typical of the Succulent Karoo Biome and in particular of the Namaqualand area. A bioclimatic envelope was modeled to establish the area in which this species might feasibly be used. The regional bioclimatic potential for C. inaequale proved to be extensive, covering approximately 17,500 km 2 . An examination of the functional role of C. inaequale showed it to facilitate early seedling survival in this community. A nearest-neighbor study found no evidence of interspecific competition between C. inaequale and its dominant co-occurring species, possibly due to vertical stratification of rooting structures. Cephalophyllum inaequale significantly reduced wind speed and soil erosion. Experiments to test the feasibility of propagating, reintroducing, and establishing this species showed that it easily germinates from seed, and transplanted cuttings have a high survival rate. This study demonstrates that C. inaequale has potential for use in initiating the restoration of degraded lands in South Africa.

With probably fewer than 3000 individuals alive in the biodiversity hotspot of the Succulent Karoo in southern Africa, populations of the endemic, Giant Quiver Tree, Aloe pillansii, are thought to be declining and thus threatened with extinction. Using repeat photography and field data we investigated the long-term changes in one population of A. pillansii at its type locality, the roughly 100 ha Cornell's Kop in the Richtersveld, South Africa. There are currently 75 individuals alive at this site. Of these, 44% are <1 m in height (seedlings), 4% are 1 -3 m (juveniles) and 52% are >3 m (adults). An analysis of 14 repeat photographs shows that since 1937 an average of 1.4% of the plants >3 m in height has died annually. At this rate all the remaining 39 plants on Cornell's Kop in this size class will be dead in 71 years. The relative paucity of plants in the 1 -3 m size classes could be explained by several factors including plant theft, animal damage and unfavourable recruitment conditions during the first 80 years of the 20th century. Annual growth rates decrease as plants age. Individuals <1 m in height grow at 42.5 mm yr )1 while plants 1 -3 m and those >3 m grow at 31.0 and 16.4 mm yr )1 respectively. At 8 m, the tallest plant on Cornell's Kop could be as old as 382 years and thus to maintain itself at this site, A. pillansii would only need to recruit relatively infrequently. The relatively high proportion of seedlings suggests that conditions have recently been favourable for recruitment at this site. Seedling ages, estimated from their heights, indicate that over 50% of the plants <1 m in height germinated 5 -10 years ago. This is consistent with local rainfall records which show that rainfall was consistently above the long-term annual average of 75 mm during this period. However, the loss of six seedlings from the population in the last 5 years, probably due to grazing or theft, suggests that without intervention this species will not survive on Cornell's Kop.

Africa; nearly 13 million km 2 or 5.1 million square miles), although a signifi cant amount of livestock production also occurs within the agricultural lands and some also on the margins of bare soil environments, particularly during above-average rainfall years. Their composition and productivity are infl uenced primarily by rainfall, fi re, and grazing, although over longer time frames, changes in temperature and the concentration of atmospheric CO 2 are also important.A wide range of land use systems, governed by often complex land tenure arrangements, affect Africa's rangelands. Within this complexity, there are three main types of livestock systems: 1) industrial livestock systems, 2) agropastoral and pastoral systems, and 3) smallholder croplivestock systems. Irrespective of the system used, however, livestock are central to the livelihoods of more than 200 million Africans who rely on them for income from sales of milk, meat, and skins, and for protein consumption, draft power, and ritual and spiritual needs, among other uses. Owning livestock is one way by which many people are able to diversify their risk, increase their assets, and improve their resilience to sudden changes in climate, disease outbreaks, and unfavorable market fl uctuations.Agricultural production (of which livestock production is an important part) not only contributes to the livelihoods of individual households, but also to the continent's economy as a whole. It accounts for 20-30% of the gross domestic product of sub-Saharan Africa and 55% of African exports. Despite rapid rates of urbanization, more than 60% of Africans still live in rural areas, and more than 56% of the total labor force (estimated at over 200 million people) was engaged in some form of agricultural activity in 2002. Estimates are that nearly 90% of the poorest inhabitants work primarily in agriculture and more than two thirds own E ven though Africa has contributed the least to global greenhouse gas emissions, it is considered the continent most susceptible to climate change impacts because of 1) the large proportion of people who live in the subtropics, a region predicted to be affected by increased temperature and reduced precipitation; 2) the high dependence of people on natural resources, livestock, and agriculture for their livelihoods; 3) extreme poverty in many parts of Africa, which makes it diffi cult for affected people to respond to an increased incidence of drought and fl oods; and 4) the degraded state of Africa's natural resources, which renders them less resilient to the impact of higher temperatures and lower and more variable precipitation. Africa's Rangelands and Their Importance to the ContinentAfrica covers about 30 million km 2 (11.6 million square miles) and, although it is slightly smaller in size than Asia, it is unique in having its land mass distributed more or less equally in both hemispheres. Its vast length (8,050 km or 4,990 miles), breadth (7,560 km or 4,867 miles) and elevation range (−153 to 5,895 m or −500 to 19,340 feet) results...

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