Recent glacial recession in the Rwenzori Mountains of East Africa due to rising air temperature

Based on field surveys and analyses of optical spaceborne images (LandSat5, LandSat7), we report recent decline in the areal extent of glaciers in the Rwenzori Mountains of East Africa from 2.01 +/- 0.56 km(2) in 1987 to 0.96 +/- 0.34 km(2) in 2003. The spatially uniform loss of glacial cover at lower elevations together with meteorological trends derived from both station and reanalysis data, indicate that increased air temperature is the main driver. Clear trends toward increased air temperatures over the last four decades of similar to 0.5 degrees C per decade exist without significant changes in annual precipitation. Extrapolation of trends in glacial recession since 1906 suggests that glaciers in the Rwenzori Mountains will disappear within the next two decades

Climate change and the aquatic ecosystems of the Rwenzori Mountains, Uganda

The Rwenzori Mountains are home to one of the last remaining tropical icefields outside of the Andes. Over the last century, equatorial icefields of the East African highlands have been steadily shrinking but the precise climate tropical alpine glaciers remain unclear. More than a decade had passed since the last detailed measurements of glacial cover were made in the Rwenzori Mountains. Recent evidence from Kilimanjaro suggests that its icecap will disappear entirely by the year 2020(1). The Rwenzori glaciers contribute meltwater flows to aquatic ecosystems of the Rwenzori Mountains National Park, a Word Heritage Site featuring spectacular, rare Afroalpine flora and fauna, and are headwaters of the River Nile. With the overall aim of assessing the impact of recent climate change on alpine aquatic ecosystems of the Rwenzori Mountains, a collaborative, international research team led by the University College London (United Kingdom) and Makerere University (Uganda), and involving the Institut für Geographie from the University of Innsbruck (Austria) and Water Resources Management Department (Uganda) was assembled in order to pursue three primary scientific objectives: • to assess the magnitude of current glacial recession; • to assess the impact of glacial recession on alpine riverflow; and • to assess recent environmental change from observational datasets and available, environmental archives stored in lake sediment and glacial ice

LAND USE/COVER CHANGE PATTERNS IN HIGHLAND ECOSYSTEMS OF LAKE BUNYONYI CATCHMENT IN WESTERN UGANDA

Land use and cover changes influence the livelihood and degradation of fragile ecosystems. The extents of these changes in pattern were investigated in Lake Bunyonyi Catchment which lies in the South Western Highlands of Uganda. The dynamics and magnitude of land use and cover changes were assessed using Landsat (TM/ETM+) satellite images and collection of socio-economic data through interviews. The images were processed and analysed using the mean-shift image segmentation algorithm to cluster and quantify the land use and cover features. The study noted that in the assessment period 1987-2014, the small-scale farmlands, open water and grasslands remained quasi constant; while the woodlots followed a quadratic trend, with the lowest acreage experienced in 2000. The tropical high forests and wetlands cover types experienced significant decline over the years (P<0.05). Patches of small-scale farmlands, woodlots, and wetland interchangeably lost or gained more land dependant on climate variability. Even though the tropical high forest lost more than it gained, it only gained and lost to small scale farmland and woodlots; while grassland mainly lost to small scale farmland and woodlots.L\u2019occupation du sol et les changements de couverture influencent la subsistance et la d\ue9gradation des \ue9cosyst\ue8mes fragiles. La tendance des niveaux de ces changements \ue9taient \ue9valu\ue9e dans le basin versant du lac Bunyonyi qui relie les r\ue9gions montagneuses du Sud-Ouest d\u2019Ouganda. Les dynamiques et l\u2019 envergure d\u2019utilisaton de la terre et les changements de couverture \ue9taient \ue9valu\ue9es en utilisant les images du satellite Landsat (TM/ETM+) et la collecte des donn\ue9es socio-\ue9conomiques \ue0 travers des interviews. Les images \ue9taient trait\ue9es et analy\ue9es en utilisant l\u2019algorithme de segmentation de passage-moyen-d\u2019image pour grouper et quantifier les occupations du sol et les caract\ue9ristiques de la couverture. L\u2019\ue9tude a montr\ue9 que dans la p\ue9riode d\u2019\ue9valuation de 1987-2014, la petite \ue9tendue de terres cultivables, l\u2019eau libre et les prairies sont demeur\ue9es quasi constantes; tandis que les terres bois\ue9es ont suivi une tendance quadratique, avec la plus petite superficie observ\ue9e en l\u2019an 2000. Les grandes for\ueats tropicales et les zones humides ont exp\ue9riment\ue9 un d\ue9clin significatif au cours des ann\ue9es (P<0.05). Les petites parcelles de terres agricoles, les terres bois\ue9es, et les zones humides indistinctement ont perdu et gagn\ue9 plus de terres d\ue9pendamment de la variabilit\ue9 climatique. Bien que la grande for\ueat tropicale aie perdu plus qu\u2019elle en a gagn\ue9e; elle a seulement perdu de tr\ue8s petites \ue9tendues de terres agricoles et bois\ue9es; alors que les prairies ont principalement perdu de tr\ue8s petites \ue9tendues de terres agricoles et bois\ue9es

Catalyzing Transformations to Sustainability in the World's Mountains

Mountain social‐ecological systems (MtSES) are vital to humanity, providing ecosystem services to over half the planet's human population. Despite their importance, there has been no global assessment of threats to MtSES, even as they face unprecedented challenges to their sustainability. With survey data from 57 MtSES sites worldwide, we test a conceptual model of the types and scales of stressors and ecosystem services in MtSES and explore their distinct configurations according to their primary economic orientation and land use. We find that MtSES worldwide are experiencing both gradual and abrupt climatic, economic, and governance changes, with policies made by outsiders as the most ubiquitous challenge. Mountains that support primarily subsistence‐oriented livelihoods, especially agropastoral systems, deliver abundant services but are also most at risk. Moreover, transitions from subsistence‐ to market‐oriented economies are often accompanied by increased physical connectedness, reduced diversity of cross‐scale ecosystem services, lowered importance of local knowledge, and shifting vulnerabilities to threats. Addressing the complex challenges facing MtSES and catalyzing transformations to MtSES sustainability will require cross‐scale partnerships among researchers, stakeholders, and decision makers to jointly identify desired futures and adaptation pathways, assess trade‐offs in prioritizing ecosystem services, and share best practices for sustainability. These transdisciplinary approaches will allow local stakeholders, researchers, and practitioners to jointly address MtSES knowledge gaps while simultaneously focusing on critical issues of poverty and food security

Rapid epidemiological mapping of onchocerciasis in areas of Uganda where Simulium neavei SL is the vector

Objective: To test whether Rapid Epidemiological Mapping of Onchocerciasis (REMO) was suitable for mapping of onchocerciasis in foci where S.neavei sl is the primary vector.Design: Topographical maps of scale 1:250,000 were used in demarcating regions into ecotopographic divisions and zones in order to identify potential onchocerciasis endemic areas.Setting: The study was conducted in Kabarole and Nebbi districts. High-risk communities were selected 30 km from each other, and closest to rivers where vector breeding appeared likely. Secondary and additional communities were selected 10 km and 20 km away from high-risk communities, respectively.Subjects or participants: Communities were mobilied for nodule palpation. A sample of thirty males aged at least 20 years, from each community that had lived in the area for at least ten years, were randomly selected and examined.Interventions: Individuals positive for at least one nodule were expressed in terms of Nodule Prevalence Rates (NPR) which were used to map the distribution of onchocerciasii.Main outcome measures: Coefficient of variation (CV) of Nodule Prevalence Rates between high risk secondary communities.Results: In Kabarole district, the results indicated a low coefficient of variation (CV) of 75 in NPR between high risk and secondary communities while in Nebbi district, higher CV of 187.4 was attained. The less varied NPR implies that communities in Kabarole were almost equally exposed to onchocerciasis while highly varied situation in Nebbi indicated decreasing NPR with increasing distance from high-risk communities.Conclusion: REMO is applicable in areas where S.neavei sl k the primary vector, for identification and mapping communities requiring mass treatment with ivermectin

Utilisation des ressources en eau et implications pour la sécurité humaine dans le bassin du lac Victoria en Afrique de l'est

International audienceThis synthesis/review paper attempts to explore water resource use issues in the Lake Victoria Basin [LVB] andwhat implications these would have on human security in the basin. Use was made of both primary and secondary datato analyse: (1) water resource use issues and their implication for human security, and (2) existing initiatives/ policies/ programmesin water resources management to improve human security. Anecdotal evidence suggests that the LVB is facedby an array of stressors operating in combination, including hydrological and climate change (reduced amounts of rainfall,unpredictability of rainfall seasons, shifts in rainfall distribution patterns), discharge of waste materials (municipal and industrialwastes); intense resource extraction and fisheries depletion; political uncertainty; land use and cover change [increasingurban and de-vegetated catchments] and increased pollution loading [horticultural and industrial]. How thesestressors impact on the water resources in the context of global changes is still unclear in the LVB. The paper argues that increasingstress from global change in the basin will lead to further degradation and dwindling of the vital water resource basethat would have serious implications for human security. Innovative and strategic water resources management approachessuch as incentive/financing mechanisms (PES), information/education/research and development, command and controlmeasures (penalties for inappropriate use) at different governance scales are therefore required to protect the integrity oftrans-boundary basins like the LVB.Dans cette synthèse les auteurs examinent les questions soulevées par l’exploitation de la ressource en eaudans le bassin du lac Victoria (LVB), en Afrique de l’est. Les auteurs s’intéressent principalement à l’impact sur la vie humaine,notamment sur la survie et la sécurité et surtout l’impact sur les moyens d’existence.En Afrique, le stress hydrique concerne les pays qui manquent d’eau mais aussi les régions où il y a abondance.Les changements climatiques exacerbent la situation et les activités humaines et naturelles ont un effet sur tous les secteursdu cycle de l’eau. Parmi les menaces principales pour les êtres humains on peut citer la pollution et la pénurie d’eau.Les auteurs enquêtent sur les ressources en eau que représente le LVB. Ils examinent l’impact des changements climatiquessur les ressources en eau, ainsi que ce que cela implique pour la sécurité environnementale. Ils voient commentassurer l’utilisation efficace de l’eau à l’avenir. Ils analysent ensuite les moyens disponibles pour une gestion proactivedes ressources en eau et la promotion du développement durable de l’eau dans cette région africaine. La gestion du lacet les activités humaines du passé continuent à influer sur les stratégies de management actuelles et toute solution proposéedoit prendre en compte les tensions et les conflits potentiels entre les différents pays, riverains et acteurs, à savoir,la Tanzanie, le Kenya, l’Ouganda, le Burundi et le Rwanda.Situé à 1100 m au-dessus du niveau de la mer, le lac Victoria est le plus grand lac d’eau douce en Afrique. Alimentépar une quinzaine de fleuves principaux et drainé par le Nil blanc, c’est aussi une région importante de zones humides.Une population de 30 millions de personnes habite le bassin et le PIB annuel est estimé à environ 30 milliards dedollars. L’urbanisation se développe et la densité de la population riveraine s’accroit de façon très importante. Les eauxdu lac sont exploitées comme source d’eau potable, de nourriture, d’énergie, d’irrigation, pour le transport, comme sitede rejet pour les eaux usées et pour certains déchets. Des données récentes démontrent l’eutrophisation du lac. À la finde 2012, la capacité en hydroélectricité créée par les eaux du Nil qui quittent le lac augmentera à 450 MW.Les sources principales de stress environnemental - dans le lac, dans la zone littorale, dans le bassin et au-delàdu bassin - mènent à une dégradation de l’écosystème du LVB et ont un effet négatif sur l’économie de la région et surles moyens d’existence des populations lacustres. On s’inquiète donc pour la détérioration de la qualité de l’eau, pourl’augmentation de la pollution et de l’eutrophisation et pour l’impact des changements climatiques mondiaux sur lesressources en eau. L’existence des populations lacustres est donc fragilisée.Le niveau des eaux du lac varient naturellement, mais depuis plus d’une décennie on observe une baisse généraledu niveau ce qui occasionne des pertes en tout genre notamment pour les transporteurs, les pêcheurs et pour l’hydroélectricité.Les pays riverains reconnaissent que la bonne gestion des eaux du lac est donc cruciale pour l’économiede la région, pour la protection de la biodiversité et les zones humides ainsi que pour le maintien de l’intégrité environnementaledu LVB.Au coeur des ces préoccupations se trouve la sécurité humaine. Dans un avenir proche on estime qu’il ne seraplus possible de soutenir une population en croissance permanente. Les mauvaises pratiques en agriculture et en élevagemais aussi dans les forêts sont en partie responsables des menaces pour la sécurité humaine. La qualité de l’eau sedétériore et bientôt elle ne sera plus potable; le manque d’eau pour la production agricole qui est la source de conflitsentre différents acteurs conduirait à des pénuries d’alimentation. Le manque d’eau est ainsi source de tensions dans lebassin tout comme l’excès d’eau quand la région n’arrive pas à gérer la précipitation excessive et les inondations. Ces dernièressont en grande partie imputables à l’activité humaine (déforestation, perte de la couche végétale (terre arable),conversion des zones humides…). La contamination de l’eau affecte la santé des populations directement : pollution industrielle, eaux usées non traitées, déchets agricoles et prolifération de la biomasse algale qui mène à la disparitiondes poissons et à la destruction de l’habitat aquatique. Des tensions et des conflits au niveau de l’état, de la région, voireau niveau de chaque foyer aggravent les menaces qui pèsent sur la sécurité sanitaire et économique de la populationnotamment entre les acteurs en amont et en aval du bassin. La présence de barrages et l’inconstance de la précipitationajoutées à une surextraction importante de l’eau exacerbent la situation politique et économique. La santé publique estmenacée par une combinaison de facteurs qui favorisent l’apparition de maladies contagieuses ou de maladies véhiculéespar l’eau. Les auteurs identifient les stratégies pour une gestion optimale de l’eau du LVB et préconisent essentiellementune gestion raisonnée de la ressource qui dépasse les frontières nationales. Ils prônent le recours aux organismes internationauxpour la résolution amicale des conflits. En conclusion ils déplorent l’héritage post-impérial et l’existence de structures colonialistes mises en place pour servir une élite urbaine qui perdure

Expert survey data on key challenges, drivers, and ecosystem services across mountains worldwide

Data are survey responses collected between 2014-2016 from experts working in 57 different mountain systems around the world, assessing threats to mountain social-ecological systems (MtSES) and the cross-scale ecosystem services MtSES provide.Mountain social-ecological systems (MtSES) are vital to humanity, providing ecosystem services to over half the planet's human population. Despite their importance, there has been no global assessment of threats to MtSES, even as they face unprecedented challenges to their sustainability. With survey data from 57 MtSES sites worldwide, we test a conceptual model of the types and scales of stressors and ecosystem services in MtSES and explore their distinct configurations according to their primary economic orientation and land use. We find that MtSES worldwide are experiencing both gradual and abrupt climatic, economic, and governance changes, with policies made by outsiders as the most ubiquitous challenge. Mountains that support primarily subsistence-oriented livelihoods, especially agro-pastoral systems, deliver abundant services but are also most at risk. Moreover, transitions from subsistence- to market-oriented economies are often accompanied by increased physical connectedness, reduced diversity of cross-scale ecosystem services, lowered importance of local knowledge, and shifting vulnerabilities to threats. Addressing the complex challenges facing MtSES and catalyzing transformations to MtSES sustainability will require cross-scale partnerships among researchers, stakeholders and decision-makers to jointly identify desired futures and adaptation pathways, assess tradeoffs in prioritizing ecosystem services, and share best practices for sustainability. These transdisciplinary approaches will allow local stakeholders, researchers and practitioners to jointly address MtSES knowledge gaps while simultaneously focusing on critical issues of poverty and food security.Ideas presented in this paper were first developed at a workshop supported by the Mountain Research Initiative (MRI), the Colorado State University (CSU) Warner College of Natural Resources, and the CSU Office of International Programs. Further support was provided by the National Science Foundation, NSF #DEB 1414106. RM was supported under the Climate Change Impacts on Ecosystem Services and Food Security in Eastern Africa (CHIESA) funded by the Ministry of Foreign Affairs of Finland