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The occurrence of wet and dry spells is a phenomenon most often used to identify the arid and semi-arid lands (ASAL) in Kenya. The use of first-order Markov processes that are embedded into a computer model to determine the critical climate extremes is presented. The model uses the concepts of conditional probability, Poisson probability distribution function and chi-square testing to predict the critical spells. The daily rainfall data (1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000) for two weather stations in the Kano Plains (Kenya) have been used to illustrate model application. For example, based upon the bimodal rainfall pattern in the study area, the model revealed the length of the critical dry spell to be 14 days in the long rainy season and 12 days in the short rainy season, while the critical wet spell was found to be 12 and 8 days, for the long and short rains respectively for Ahero Irrigation Scheme. It is recommended that a climate and environmental audit in the Kano Plains for the determination of land and water management strategies include critical dry and wet spell determination. This will enhance more sustainable planning and utilization of the crucial water and land resources in the region and in other tropical rangelands.

To offer an increased understanding of the spatial patterns, temporal, social and physical predictors of the conversion and transformations of land use in Lake Victoria basin, an assessment of proximate and underlying forces is presented. This study discusses key theoretical underpinnings for the manifold linkages existing between selected drivers of land‐use changes around the basin and their consequences on human well‐being. Using a meta‐analytical research design, the paper analyses ecosystems level cases of the causes of land use and cover changes in the basin, to determine any spatio‐temporal or institutional patterns and dynamics. A suite of recurrent core variables has been identified to influence land use and cover changes in the basin. The most prominent of these at the underlying category are climatic factors, economic factors, institutions, national and regional policies, population growth and other remote influences. At the proximate level, these factors drive cropland expansion, overgrazing, infrastructure extension and rates of land degradation. These are supported by empirical evidence from the basin. This assessment is crucial for appropriate local and transboundary policy interventions, which have to be fine‐tuned to the locale‐specific dynamic patterns associated with the inherent ecosystems changes.

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Understanding future ecosystem changes is central to sustainable natural resource management especially when coupled with in‐depth understanding of impacts of drivers, such as governance, demographic, economic and climate variations and land use policy. This offers comprehensive information for sustainable ecosystem services provision. A foresight process of systematic and presumptive assessment of future state and ecosystem integrity of Lake Victoria basin, as participatory scenario building technique, is presented. Four scenarios have been illustrated as possible future states of the basin over the next twenty years. Using a scenario building model developed in Ventana Simulation (VENSIM®) platform, the paper presents a scenario methodology for tracking changes in lake basin ecosystem status. Plausible trends in land use change, changes in lake levels and contribution of fisheries are presented. This is part of an initial attempt to setup long‐term environmental policy planning strategies for Lake Victoria basin. The assumptions, driving forces, impacts and opportunities under each scenario depict major departure and convergence points for an integrated transboundary diagnosis and analysis of regional issues in the basin as well as strategic action planning for long‐term interventions. The findings have been presented in terms of temporal, spatial, biophysical and human well‐being dimensions. The attempts in this study can be embedded in a policy framework for basin management priority setting and may guide partnerships for environmental management.