Spatially explicit, individual-based modelling of pastoralists' mobility in the rangelands of east Africa

An agent based-model of mobility of pastoralists was developed and applied to the semi-arid rangeland region extending from southern Ethiopia to northern Kenya. This model was used to investigate temporal adaptation of pastoralists to the spatial heterogeneity of their environment. This dissertation describes the development, structure, and corroboration process of the simulation model, Pastoral Livestock Movement Model (PLMMO). PLMMO is a spatially explicit, individual-based pastoralists-animal foraging and movement model. It simultaneously simulates the foraging and movement behavior of individual pastoralists and their livestock in a rangeland ecosystem. Pastoralists?? herd mobility patterns and other measures of movement were compared to data from field studies. Predictions of the model correspond to observed mobility patterns across seasons. The distances moved were found to be significantly correlated (r2 = 0.927 to 0.977, p<0.0001) to drought and non-drought climatic regimes. The PLMMO model therefore proved to be a useful tool for simulating general movement patterns of pastoralists relative to movement range sizes in the pastoral rangelands of southern Ethiopia and northern Kenya. We then used the PLMMO model to explore the impact of emerging changes in rangeland use in the study area. The ways in which pastoralists?? mobility patterns adapt to emerging challenges in the study area were explored by simulating the following four scenarios: 1) climate change with concomitant reduction in forage yield, 2) climate change with concomitant improvement and higher variability in forage yield, 3) increased livestock population densities and 4) improved access to water. The climate induced change scenario with increased and more variable forage production resulted in the shortest distances moved by pastoralists in comparison to all other scenarios. The total search distances under this scenario were only 20% of normal season distances. The improved water access scenario also returned a significant (p=0.017) drop in distances moved. There was, however, no significant impact on either increase in livestock numbers or reduction in available forage on mobility. We judged the agent-based model PLMMO developed here as a robust system for emulating pastoral mobility in the rangelands of eastern Africa and for exploring the consequences of climate change and adaptive management scenarios

Effects of Post Eviction Resettlement on Land-Use and Cover Change in Uganda’s Oil Exploration Areas

Evaluation of the changes in land use and land cover change (LULCC) in respect to oil exploration across the Albertine region in Uganda has been focused around the exploration areas and protected areas, with no attention to the potential impacts of evictees’ activities on resettled areas. This study used LANDSAT images to analyze the land use and land cover changes (LULCC) among the period before eviction (2002 and 2005) at the climax of eviction and resettlements (2005-2011), and during the post-resettlement period (2011-2015) to quantify the impacts of resettlements on the environment. LANDSAT images were processed using ERDAS IMAGINE software and analyzed using ArcGIS 10.1 to determine LULCC in relation to post-eviction resettlement in the study area. Results from the study indicate. The results of the study indicate that vegetation reduced by 33.08 percent, woodland were converted into settlements by 48 percent while farmlands increased by 18.3 percent. Non vegetated areas increased during resettlements however they reduced five years after eviction which indicated the ability of the ecosystem to stabilize. The study proved that post eviction induced resettlements can yield potential environmental effects to resettled areas. It is important therefore to plan and implement other means of additional source of income and construction materials for evictees to abate vegetation clearance and hence rescue the woodland. The study also recommends maintenance of an optimum population and well-planned pre eviction resettlement schemes

ABUNDANCE AND DIVERSITY OF NATIVE FORAGE SPECIES IN PASTORAL KARAMOJA SUB-REGION, UGANDA

Low input pastoral production systems rely exclusively on natural forage resourcesin space and time. Information on the abundance and diversity of such pastures is vitalin improving livestock production and managing the biodiversity of grazing landscapes. Thisstudy documented grass and browse forage species utilised in pastoral Karamoja, and determinedtheir relative abundance by district, season and grazing land cover. Up to 65 grass and110 browse species were utilised in Karamoja Sub-region. In situ assessments revealed thatChloris, Hyparrhennia, Sporobolus, Pennisetum, Aristida, Cynodon, Eragrostis, Setaria, andPanicum grasses had higher relative abundance. Triumfetta annua, Indigofera erecta, Acaciadrepanolobium, Grewia holstii, Acacia kirkii, Acacia mellifera, Acacia tortolis, Maeruapseudopetalosa, Acacia oerfota, and Ocimmum canum woody species were the most abundant.From the community assessment, Hyparrhennia, Chloris, Panicum, Bracharia, Eragrostis, and Setaria grasses and Acacia mellifera, Cadaba farinose, Acacia oerfota, Acaciadrepanolobium, Caparis tormentosa, Maerua pseudopetalosa and Hisbiscus micrantha woodyplants were identified as the most abundant among the grazing land cover. The grass andbrowse forage species varied by season, location, and land cover type. The study also founddetailed local knowledge of grass and browse forage species in the community. This study hasshown the existence of high diversity among grass and browse forage species with differentiatedrelative abundance across space and time. This, and the detailed communal culturalknowledge, form a basis for the improvement of livestock production as well as biodiversityconservation in Karamoja sub-region

Effects of heterogeneous land use/cover types on river channel morphology in the Solo River catchment, Eastern Uganda

In the tropics, unmonitored land use/cover types cause significant effects on the narrowing and widening of river channels which affects the integrity of water resources. River channel planform extent was characterized using Landsat images, while water and bedload samples were collected and analysed for a period of one year. The results revealed that in 1986, the channel planform covered 3.7 sq km in length than in 2013 where it increased to 4.2 sq km. Wetland (537.1mgl−1) and bushland (186.3mgl−1) cover types had the highest concentration of suspended sediments. Fine sand (0.25 mm), silty sand (1 mm) and silty clay (0.125 mm) bedload particle types dominated the riverbed along the channel from the sampled land use/cover types. The high concentration of sediments, bedload materials, bank instability, and streamflow were significant contributors to the narrowing and widening of the channel (p < 0.05). Agricultural land use was the major contributor of channel aggradation (0.8 m) and degradation (0.25 m) compared to tree plantations, bushlands, forest and wetland cover types

Land Cover and Soil Properties Influence on Forage Quantity in a Semiarid Region in East Africa

Soil properties contribute to the widely recognised resilience of semiarid areas. However, limited attention has been given in providing a scientific basis of how semiarid soil properties in the various land covers occur and how they influence forage quantity. This study investigated the influence of different soil properties and land cover types on herbaceous biomass quantity in the Karamoja subregion of Uganda. A completely randomized design in three land cover types (thickets and shrublands, woodlands, and savannah grasslands) was implemented. In each vegetation type, 50 × 40 m plots were demarcated with nested plots to facilitate clipping of the herbaceous layer. Composite soil samples at two depths (0–15 cm, 15–30 cm) were obtained from each plot. The results showed that soil properties varied across land cover types. Soil pH ranged between 6.9 and 8.1 and SOM, N, P, and K were generally low in all land cover types. Soil hydraulic properties revealed the existence of rapid to very rapid permeability in thickets/shrublands, grasslands, and woodlands. Percent change in soil properties (0–15 cm to 15–30 cm) was highest in P, Ca, Mg, Na, and SOM. In the grasslands, P positively (p≤0.01) influenced herbaceous biomass, whereas pH, K, Na, % sand, and % clay, N, and SOM had a negative relationship with herbaceous biomass (p≤0.05). Herbaceous biomass in the thickets/shrublands was negatively influenced by P, Ca, and Mg and % clay and positively by N and % silt (p≤0.05). Only N and SOM were significant determinants of herbaceous biomass in the woodlands (p≤0.05). The low level of soil nutrients observed in this study reveals the fragility of semiarid soils, indicating the need for sustainable landscape management