BEST addresses the research issue that African drylands are fast approaching a tipping point of range enclosure, with associated loss of wild and domestic grazer mobility, and attendant loss of ecosystem services and of poor people's livelihoods. The shift to an enclosed (or conversely back to an open) state is driven by the interplay of changing policies on land tenure and natural resource management. The effects of these policies, which are integrated at the level of household tradeoff decisions and subsequent land use choices, are expressed in environmental and social sustainability implications. BEST asks the research question: How do different policy and economic drivers shape household decisions on land use choices, and with what ecosystem services and poverty implications? BEST's objectives are therefore: (1) to develop a conceptually innovative approach focusing on the intersection of changing land tenure and NRM policies and their impact on tipping drylands from open, resilient rangelands with mobile domestic and wild animals and often cash-poor but relatively secure and resilient pastoral livelihoods, into a closed, impoverished state (2) to leverage existing datasets (biophysical and socioeconomic), extract maximum analytical power and develop policy relevant lessons from cross-border comparative analyses of Kenya/ Ethiopia Boran and Kenya/Tanzania Maasai systems (3) to model household-level decisions on drylands resource use choices in different policy and economic contexts, integrating biophysical and socioeconomic dimensions, maintaining a disaggregated level of analysis across household types and conditions, and exploring policy and economic incentives fostering conservation-compatible choices (4) to develop policy scenario evaluations to support better ecosystem management, making more visible and comprehensible poor people's resource use choices, and enhancing their livelihoods (5) to build on local knowledge, engaging stakeholders at all levels, through networking, field consultation, workshops, and media outputs, from concept to beyond project end. BEST will also share knowledge and build capacity across the whole partnership and beyond, through collaborative working, stakeholder engagement and a wide range of outputs pitched at policy as well as scientific audiences - to build capacity across the collaboration and beyond, - to ensure maximum impact, leveraging dissemination through non-funded project partners, research and practitioner networks alongside the stakeholder engagement activities BEST research design, methods and materials use conceptually innovative modelling, alongside major extant datasets, and a cross-border comparative analysis encompassing three of the poorest African countries, to develop understanding of household decisions over land use. The BEST partnership combines in depth experience of the biophysical and socioecological dimensions of the ecosystems studied, advanced modelling capabilities, and outstanding experience in communications and engagement, with significant research, policymaker and practitioner networks. UK and non-UK members of the BEST partnership already manage major datasets necessary for the work. Together with non-funded partners ASARECA, STEPS and TAWIRI, and the involvement of BEST research partners with current research collaborations, the BEST partnership aims not only to deliver findings that will help evaluate policy scenarios, giving credible and relevant insight into the ecosystem services and poverty implications of different land tenure and NRM policies, but also to ensure those findings and tools are embedded into policymaking and practice.

Uganda, Kenya, Ethiopia and Tanzania

East Africa (EA) has one of the world's fastest growing populations, with maxima around water-bodies and rapid urbanisation. Climate change is adding to existing problems increasing vulnerability of the poorest. HyCRISTAL is driven by EA priorities. EA communities rely on rainfall for food via agriculture. EA's inland lakes are rain-fed and provide water, power and fisheries. For EA's growing cities, climate impacts on water resources will affect water supply & treatment. HyCRISTAL will therefore operate in both urban & rural contexts. Change in water availability will be critical for climate-change impacts in EA, but projections are highly uncertain for rain, lakes, rivers and groundwater, and for extremes. EA "Long-Rains" are observed to be decreasing; while models tend to predict an increase (the "EA Climate paradox") although predictions are not consistent. This uncertainty provides a fundamental limit on the utility of climate information to inform policy. HyCRISTAL will therefore make best use of current projections to quantify uncertainty in user-relevant quantities and provide ground-breaking research to understand and reduce the uncertainty that currently limits decision making. HyCRISTAL will work with users to deliver world-leading climate research quantifying uncertainty from natural variability, uncertainty from climate forcings including those previously unassessed, and uncertainty in response to these forcings; including uncertainties from key processes such as convection and land-atmopshere coupling that are misrepresented in global models. Research will deliver new understanding of the mechanisms that drive the uncertainty in projections. HyCRISTAL will use this information to understand trends, when climate-change signals will emerge and provide a process-based expert judgement on projections. Working with policy makers, inter-disciplinary research (hydrology, economics, engineering, social science, ecology and decision-making) will quantify risks for rural & urban livelihoods, quantify climate impacts and provide the necessary tools to use climate information for decision making. HyCRISTAL will work with partners to co-produce research for decision-making on a 5-40 year timescale, demonstrated in 2 main pilots for urban water and policies to enable adaptive climate-smart rural livelihoods. These cover two of three "areas of need" from the African Ministerial Council on Environment's Comprehensive Framework of African Climate Change Programmes. HyCRISTAL has already engaged 12 partners from across EA. HyCRISTAL's Advisory Board will provide a mechanism for further growing stakeholder engagement. HyCRISTAL will work with the FCFA global & regional projects and CCKE, sharing methods, tools, user needs, expertise & communication. Uniquely, HyCRISTAL will capitalise on the new LVB-HyNEWS, an African-led consortium, governed by the East African Community, the Lake Victoria Basin Commission and National Meteorological and Hydrological agencies, with the African Ministerial Conference on Meteorology as an observer. HyCRISTAL will build EA capacity directly via collaboration (11 of 25 HyCRISTAL Co-Is are African, with 9 full-time in Africa), including data collection and via targeted workshops and teaching. HyCRISTAL will deliver evidence of impact, with new and deep climate science insights that will far outlast its duration. It will support decisions for climate-resilient infrastructure and livelihoods through application of new understanding in its pilots, with common methodological and infrastructure lessons to promote policy and enable transformational change for impact-at-scale. Using a combination of user-led and science-based management tools, HyCRISTAL will ensure the latest physical science, engineering and social-science yield maximum impacts. HyCRISTAL will deliver outstanding outputs across FCFA's aims; synergies with LVB-HyNEWS will add to these and ensure longevity beyond HyCRISTAL.