Aboveground Net Primary Productivity in Grazed and Ungrazed pastures: Grazing Optimisation Hypothesis or Local Extinction of Vegetation Species

The controversy that has surrounded herbivory studies in the last few decades prompted our investigation to establish the extent to which herbivore optimisation hypothesis or compensatory growth evidence is real. We used the traditional movable cage method to collect primary productivity data on herbage, functional groups and key individual grass species in various controlled large herbivore treatments in an east African savanna. The herbivore treatments in triplicate blocks included cattle, wild herbivores with and without mega herbivores and combinations of cattle and wild herbivores also with and without mega herbivores. The findings revealed that at herbage level, most grazed treatments (four out of five) had higher productivity than the ungrazed control and three showed grazing optimisation curve at sixth polynomial degree between monthly productivity and grazing intensity (1-g/ng). At functional group level forbs productivity was higher in the ungrazed control than in any of the grazed treatments while at individual grass species level _Themeda triandra_ productivity was higher in all grazed treatments than in ungrazed control. We conclude against presence of herbivore optimisation hypothesis at herbage, functional group and species level because of lack of attributable grazing effect in grazed treatments that matches complex ecological effects in the ungrazed treatment

Community-Based Conservation: An Emerging Land Use at the Livestock-Wildlife Interface in Northern Kenya

In East Africa, an estimated 70% of wildlife populations are dispersed outside protected areas on community land. The way of life of the pastoralists, essentially support the thriving of wildlife. However, pastoralism is slowly transiting to more sedentary forms of livestock production. The region‘s wildlife populations future now largely depends on the conservation of habitats and migratory corridors on private and communally owned lands with competing land uses. Community wildlife conservancies are one of the approaches of decentralizing wildlife management and curbing biodiversity and habitat loss at the livestock-wildlife interface environments. Further, conservancies present an avenue for restoration of degraded grazing lands and improving pastoral livelihoods. This paper reviews the community-based conservation unfolding in northern Kenya using the case of Naibung’a Wildlife Conservancy in Laikipia County. Conservancies through land zoning and range rehabilitation have contributed to improved security of wildlife, people and their livestock. Conservancies’ success depends on continued investment in vegetation recovery, grazing management, livestock marketing and benefit sharing. The perceived threats facing conservancies are pasture scarcity, cattle rustling and human-wildlife conflicts. Conservation objectives and human livelihoods in Africa are closely interlinked and lessons learnt in Naibung’a Wildlife Conservancy could particularly be useful to other similar initiatives in Africa

A Policy Brief on Adopting the Somali Camel for Enhanced Profitability and Pastoral Resilience in Northern Kenya

Persistent drought and high temperatures in Isiolo and Marsabit counties of northern Kenya repeatedly devastate livestock herds particularly cattle making the pastoralists less resilient, more vulnerable to climate change and poor. To address this challenge, an IGAD funded project promoted adoption of Somali camel breed, trained farmers on improved management and also estimated potential profitability of rearing the camel. Through the project, trainers were trained and facilitated to train 240 peri-urban Somali camel producers in Isiolo and Marsabit on breeding, health, routine husbandry and marketing. Impact study documenting positive stories of change was conducted at the end. Producers who hitherto made zero money from their camels were making KES. 42,000 a month from sale of 20 litres of milk daily from only 5 milking camels; producers had adopted a new grazing management strategy that ensured daily access of the camel milk market and conservation of grazing areas around settlements; motor bikes had been adopted as means delivering milk to collection centers thus creating jobs for the youth; the beneficiary producers were spending more money on production inputs. In terms of policy, the county governments of Isiolo and Marsabit need to appreciate the huge business potential in Somali camel rearing and the magnitude of positive change that can be brought about by capacity training of producers on improved camel management technologies and agree to allocate more funds in support of livestock production extension services

Combining ability of maize (Zea mays L.) inbred lines resistant to stem borers

Ten inbred parents with varying resistance levels to Chilo partellus and Busseola fusca were crossed in a half diallel mating scheme to generate 45 F1 hybrids. The hybrids and five commercial checks were evaluated across four locations in Kenya under artificial and natural infestation in 2009. Genotype (G) by environment (E) interaction (G x E) was non-significant for stem borer leaf damage, number of exit holes and tunnel length, suggesting that screening for stem borer resistance at one location would be adequate. On the other hand, G x E and general combining ability (GCA) x environment interactions were highly significant for gray leaf spot and turcicum leaf blight, indicating an inbred line resistance to a disease in one location may have a different reaction to the same disease in another location. The results of combining ability analysis showed that GCA effects were significant for stem borer resistance traits (leaf damage scores, number of exit holes, and tunnel length) while the opposite was true for specific combining ability (SCA) effects. Parents 5, 2, 6, 9 and 3, were good sources of genes for higher grain yield while parents 1 and 4 were good sources of resistance genes for stem borers. Hybrid 5 x 9 was the best performing hybrid in grain yield (6.53 t/ha) across the locations, while hybrid 1 x 4 was the least performing in grain yield (3.08 t/ha). The source of stem borer resistance identified in the study may be useful for improving levels of stem borer resistance in maize breeding  programs in eastern and southern Africa.Key words: Combining ability, maize, inbred lines, stem borers

The decline of water hyacinth on Lake Victoria was due to biological control by Neochetina spp

There has been some debate recently about the cause of the decline of water hyacinth on Lake Victoria. While much of this evidence points to classical biological control as the major factor, the El Niño associated weather pattern of the last quarter of 1997 and the first half of 1998 has confused the issue. We argue first that the reductions in water hyacinth on Lake Victoria were ultimately caused by the widespread and significant damage to plants by Neochetina spp., although this process was increased by the stormy weather associated with the El Niño event; second that increased waves and current on Lake Victoria caused by El Niño redistributed water hyacinth plants around the lake; and third that a major lake-wide resurgence of water hyacinth plants on Lake Victoria has not occurred and will not occur unless the weevil populations are disrupted. We conclude that the population crash of water hyacinth on Lake Victoria would not have occurred in the absence of the weevils, but that it may have been hastened by stormy weather associated with the El Niño event

Tsetse control and land-use change in Lambwe valley, south-western Kenya

For a long time, trypanosomosis, spread by the tsetse fly Glossina, constrained human settlement in the Lambwe Valley, a south-western Kenya rangeland. After lengthy efforts to control tsetse over many years, the valley is currently experiencing an increase in human population growth rate, and rapid changes in land-use and cover are taking place. Using timeseries aerial photograph interpretation, social survey methods, and a review of human population trends over five decades, a three-fold expansion in cultivation in the settled areas over a 50-year period, with a consequent decrease in woody vegetation cover was identified. In the Ruma National Park, occupying a third of the valley floor, shrublands and thickets have expanded while open grasslands have decreased. The sudden increase of land under cultivation adjacent to prime agricultural land designated for wildlife conservation, exacerbated by bush encroachment and dwindling resources for tsetse control could provide a situation suitable for land-use conflicts. Sustainability of this unique rangeland is dependent on how judiciously the resources are shared among all stakeholders in the valley. This study suggests continued tsetse surveillance and agricultural intensification in the settled areas to minimise chances of conflicts in land-use

Effect of Balanites glabra canopy cover on grass production, organic matter and soil moisture in a southern Kenyan rangelan

A study was undertaken in Kenya’s southern savanna rangelands to determine the seasonal effect of Balanites glabra canopy cover on aboveground grass biomass, grass species composition, soil organic matter and soil moisture content. The study was conducted during the period June to December 1999 in order to capture both the dry and wet season effects. The grass biomass in the sub-canopy zone (2–4m from tree trunk) was found to be significantly higher than in the mid-canopy (0–2m from tree trunk) and open grassland zones (4–6m from tree trunk) during the dry season. However, the difference between the sub-canopy and the open grassland was not significant during the wet season, implying that the role of a tree canopy in enhancing grass biomass is greater during the dry than the wet season. Variations in percent grass species composition from the mid-canopy to the adjacent open grassland were observed, indicating that while B. glabra canopy cover favours certain grass species, other species find the microclimatic conditions under the canopy unfavourable. Soil organic matter in the mid-canopy zone was significantly higher than in the sub-canopy and adjacent open zones during both dry and wet season. Although the sub-canopy zone exhibited significantly higher soil moisture content than the mid-canopy and open grassland zones during the dry season, the difference between the subcanopy and the adjacent open grassland during the wet season was not significant, suggesting that the tree canopy influence on soil moisture is more pronounced in the dry than the wet season

The use of sociological methods to assess land-use change: A case study of Lambwe valley, Kenya

Land-use history, not readily available for most places, remains the weakest link in nearly all studies of historic vegetation change, in Africa as well as other places in the world. Notwithstanding, communities hold a great wealth of knowledge on the processes and events influencing change on the land they occupy. The Lambwe Valley, southwestern Kenya, has a multi-ethnic population of settlers from the early 1950s. These people have seen the transformation of an initially forested area with diverse challenges to their survival, to present-day scramble for the remaining high potential land. A large part of the forces driving human settlement and consequent changes in land-use and cover is attributed to the control of tsetse and trypanosomosis. The application of a socio-economic method of mapping land-use change with the participation of the community in this study depicted trends and the underlying causes. The control of tsetse fly and therefore trypanosomosis infection was significant in driving the changes in the valley. Agricultural intensification is suggested as a means to support the resultant higher populations of people and livestoc