No abstract

A study on effects of bush encroachment control techniques on rangeland productivity and tick population dynamics was conducted in Arero district of Borana zone, southern Ethiopia, for three consecutive years. The study targeted two main and dominant encroaching bush species in Borana rangeland, Acacia drepanolobium and Acacia mellifera, and their effects on some vegetation attributes and tick population dynamics. A hectare of rangeland encroached by these two acacia species was replicated/divided into three plots, and each plot was subdivided into five sub-plots to receive five treatments: cutting at 0.5 m above ground and pouring kerosene on stumps (T1), cutting at 0.5 m above ground and debarking the stumps down into the soil surface (T2), cutting at 0.5 m above ground alone (T3), cutting at 0.5 m above ground and dissecting the stumps (T4) and control (T5). Data on basal and litter covers, soil erosion and compaction, dead and re-sprouted encroaching tree/shrub species and nymphand adult-stage tick populations were collected before and after treatment applications. The applied treatments significantly influenced (p < 0.05) basal cover, nymph-and adult-stage tick population and the two encroaching tree species. The results of this study showed that T3 and T2 were good in controlling A. drepanolobium in that order. T4 and T2 had a significant effect in controlling A. mellifera in their order. Controlling bush encroachment had also a positive effect in eradicating the tick population. The most dominant grass and non-grass species observed after the control actions were Cenchrus ciliaris, Chrysopogon aucheri, Abutilon hirtum, Pennisetum mezianum, Dyschoriste hildebrandtii, Zaleya pentandra and Eragrostis papposa. Therefore, controlling encroaching tree/shrub species had created a conducive grazing area with palatable herbaceous species for the livestock and unequivocally reduced tick population which play a role in reducing cattle milk production through closing off teats. The management of bush encroachment, if sustained, will contribute in stabilizing rangelands and help minimize the negative effects of feed and food crises in the future.

Understanding the impact of land use change on soil organic carbon stock following the conversion of a semiarid rangeland into different land use types is essential to devise an appropriate and sustainable rangeland management strategy. However, there is a knowledge gap as to the impact of currently ongoing land use changes on soil organic carbon stock, which is an important rangeland ecosystem service, particularly in the face of climate change. Thus, this study was conducted to assess the effect of land use change on soil organic carbon stock in three land use types, namely, enclosures, communal grazing and cultivated lands in Borana rangeland. The result indicated that there were significant interactions between land use types and depths for soil organic carbon stock (p<0.0001) and bulk density (p=0.0055) with mean losses of 60% and 69% in soil organic carbon stock from the surface layer (0-10 cm) of communal and cultivated lands, respectively, as compared to enclosure land use type. The results indicated that communal grazing and crop cultivation in the Borana rangeland resulted in significantly decreased soil organic carbon stock. Hence, the current trend must be curbed to put back the system on its right track of resilience and sustainability for its long-term benefit and to mitigate the unprecedented increase in CO 2. Therefore, the results of this study would be useful for the improvement of land use management in the future.

Grazing management strategies tend to have different effects on rangeland plant production. Changes in grazing management can, therefore, affect the carbon stock potential of rangelands. Despite rangeland ecosystems being important global sinks for carbon, we know relatively little about the effect of traditional grazing management practices on their potential to store carbon. In this study, we evaluated the carbon stock and change rate of rangelands using three traditional grazing management practices in the semiarid pastoral ecosystem of eastern Ethiopia. By comparing data on vegetation and soil carbon stocks, we found that there was a strong significant difference (p < 0.001) between these different management practices. In particular, the establishment of enclosures was associated with an annual increase in carbon stocks of soil (3%) and woody (11.9%) and herbaceous (57.6%) biomass, when compared to communal open lands. Both enclosure and browsing management practices were found to have the highest levels of soil organic carbon stocks, differing only in terms of the amount of woody and herbaceous biomass. Thus, modest changes in traditional grazing management practices can play an important role in carbon storage and sequestration. Further research is required on a wider range of traditional pastoral management practices across space and time, as understanding these processes is key to combating global climate change.

Participatory impact assessment of ticks on Borana cattle milk production was conducted from January 2010 to July 2010. The objectives of this study were to assess the status of tick infestation in relation to climate change, teats blinding and milk production and to estimate the economic losses caused as a result of the effect of ticks on dairy cattle and its implications on food security in Yabello, Moyale and Meo districts of Borana zone. Multi-stage sampling technique was employed and the data was analyzed using descriptive statistics and matrix triangulation. Thus, about six villages "Ollas" were systematically identified and a total of 86 households were interviewed employing questionnaires comprising 6-12 pastoralists and agropastoralists per ten PAs which in sum contained 60-120 individuals who provided information pertaining to the objectives set; in which increase of ticks population at an alarming rate was perceived having several factors affecting and its real impact of blinding on teats which signal loss of milk production which in fact revealed economic loss and implicated food insecurity on vulnerable social groups, specifically children and elders >80 years old within the settings. Tick resistance to currently available acaricides was complained by communities. It was observed that acaricides were sold in open market and there was no strong control on illegal veterinary drug vendors. Communities also purchase these acaricides and misuse them which, contributed to the increase of acaricide resistance. This is a good indication for policy makers and local authorities to take strict action on illegal drug vendors.