Spatio-temporal epidemiology of livestock diseases in the variable semi-arid rangelands of northern Kenya.

Diseases affecting livestock can have significant impacts on the animal, humans and the economy. Participatory epidemiology and spatial analysis were conducted to assess livestock disease problems in Samburu County, northern Kenya. Key informants were selected purposively with the help of local leaders. Among the livestock, goats were identified to have the most economic importance. On the other hand Pestes des Petits Ruminants (PPR), Foot and Mouth Disease (FMD) and Camel Trypanosomiasis diseases were identified to have the highest impact on pastoral livelihood. Spatial analysis indicated that all the disease hotspots were closely related to the distribution of herds during different seasons of the year. Correlations between the mean annual rainfall and selected livestock diseases were significant for East Coast Fever (ECF) (r = - 0.767, p = 0.001, N = 15), Cattle Helminthiasis (r = 0.639, p = 0.010, N = 15), Cattle Anaplasmosis (r = 0.631, p = 0.012, N = 15) and Camel Pox (r = - 0.646, p = 0.044, N = 10). There was a strong relationship between seasonality and livestock disease epidemiology. Disease control efforts should be focused towards the hotspots in the wet season and dry season grazing areas.

Experimental prosopis management practices and grassland restoration in three Eastern African countries.

Woody species have been introduced in many parts of the world to provide economic benefits, but some of those species are now among the worst invaders, causing widespread economic and environmental damage. Management of woody species to restore original ecosystem services, such as biodiverse grassland that can provide fodder and sequester carbon, are needed to limit the impacts of alien species. However, the best management methods, i.e., the most economically efficient and effective way to remove trees and the most effective way to restore or rehabilitate the cleared land, are not developed for many species. In Eastern Africa, prosopis (Prosopis julifora) has invaded large areas of savanna and grassland, thereby affecting, among other things, fodder and water for livestock, access to dry season grazing lands and ultimately pastoral livelihoods. We tested three prosopis treatments (manual uprooting and cut stump and basal bark herbicide application) in combination with three incremental restoration interventions (divots, divots + mulching, divots + mulching + grass seed sowing). The three-year study was replicated in Ethiopia (Afar National Regional State), Kenya (Baringo county) and Tanzania (Moshi district). Prosopis survival and vegetation development, both diversity and biomass, were recorded. The prosopis treatments were all highly effective (between 85 and 100% tree mortality in almost all cases), but the two treatments that involved the complete removal of the aboveground biomass (manual and cut stump) yielded a more productive and more diverse vegetation than the treatment that killed the trees standing (basal bark). Compared to the effect of prosopis removal, the effect of restoration interventions on vegetation composition was small, indicating that most species re-established from the soil seed bank. The results show that it is possible to restore land previously invaded by prosopis. Despite the different rates of vegetation establishment and variation in species composition, the restoration interventions resulted in vegetation that in some cases contained a substantial fraction of perennial grasses. The method chosen to control prosopis depends on the availability of resources, including herbicides, and the need to remove rootstocks if the intention is to plant crops. Supplementary Information: The online version contains supplementary material available at 10.1186/s43170-023-00163-5.

Large herbivores maintain a two-phase herbaceous vegetation mosaic in a semi-arid savanna.

Many arid and semi-arid rangelands exhibit distinct spatial patterning of vegetated and bare soil-dominated patches. The latter potentially represent a grazing-induced, degraded ecosystem state, but could also arise via mechanisms related to feedbacks between vegetation cover and soil moisture availability that are unrelated to grazing. The degree to which grazing contributes to the formation or maintenance of degraded patches has been widely discussed and modeled, but empirical studies of the role of grazing in their formation, persistence, and reversibility are limited.We report on a long-term (17 years) grazing removal experiment in a semi-arid savanna where vegetated patches composed of perennial grasses were interspersed within large (>10 m2) patches of bare soil.Short-term (3 years) grazing removal did not allow bare patches to become revegetated, whereas following long-term (17 years) grazing removal, bare soil patches were revegetated by a combination of stoloniferous grasses and tufted bunchgrasses. In the presence of grazers, stoloniferous grasses partially recolonized bare patches, but this did not lead to full recovery or to the establishment of tufted bunchgrasses.These results show that grazers alter both the balance between bare and vegetated patches, as well as the types of grasses dominating both patch types in this semiarid savanna.Synthesis: Large herbivores fundamentally shaped the composition and spatial pattern of the herbaceous layer by maintaining a two-phase herbaceous mosaic. However, bare patches within this mosaic can recover given herbivore removal over sufficiently long time scales, and hence do not represent a permanently degraded ecosystem state.