DOCSLIB.ORG

Late Cenozoic Moisture History of East Africa

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Late Cenozoic Moisture History of East Africa R EPORTS 17. T. C. Onstott, M. L. Miller, R. C. Ewing, G. W. Arnold, Research Council (NERC) Ocean Margins Project re- Materials and Methods D. S. Walsh, Geochim. Cosmochim. Acta 59, 1821 (1995). search grant number 3220-GL021-GRA0782. We thank Figs. S1 to S3 18. M. A. Kendrick, R. Burgess, R. A. D. Pattrick, G. Turner, A. Craven for access to the TEM, G. Sherwood for com- Tables S1 to S5 Econ. Geol. 97, 435 (2002). ments, and J. Still for technical assistance. References 19.N.J.L.Bailey,P.Walko,M.J.Sauer,inPetroleum Geology of Northwest Europe, J. Brooks, K. Glennie, Eds. Supporting Online Material (Graham and Trotman, London, 1987), p. 711. www.sciencemag.org/cgi/content/full/309/5743/2048/ 13 June 2005; accepted 18 August 2005 20. This work is supported by the Natural Engineering DC1 10.1126/science.1116034 tectonic and magmatic processes have to be Late Cenozoic Moisture History present to accommodate the lakes; second, the climate has to sustain a positive precipitation/ evaporation balance for a substantial period of of East Africa time. Here we elucidate East African climate Martin H. Trauth,1 Mark A. Maslin,2 Alan Deino,3 changes in the Late Cenozoic, using detailed Manfred R. Strecker1 sedimentary records from 10 basins of the east- ern branch of the EARS. The large geographic Lake sediments in 10 Ethiopian, Kenyan, and Tanzanian rift basins suggest dispersion of these basins along a north-south that there were three humid periods at 2.7 to 2.5 million years ago (Ma), 1.9 transect helps to separate the effects of volcanic- to 1.7 Ma, and 1.1 to 0.9 Ma, superimposed on the longer-term aridification of tectonic and climatic influences on rift sedimen- East Africa. These humid periods correlate with increased aridity in northwest tation. Synchronous changes in the hydrological and northeast Africa and with substantial global climate transitions. These balance inferred from sediment characteristics episodes could have had important impacts on the speciation and dispersal of and silica algae (diatom) assemblages that mammals and hominins, because a number of key events, such as the origin of contrast with the volcanic-tectonic history are the genus Homo and the evolution of the species Homo erectus, took place in attributed to climate change. These relations this region during that time. suggest possible links between climate change and mammalian and hominin evolution during Recent investigations of both terrestrial and Although much smaller than the lakes in the theLateCenozoic. marine paleoclimate archives have led to a western branch and often subaerially exposed, The EARS has a great diversity of sedi- concerted debate regarding the nature of Late these basins host a rich sedimentary record, mentary environments. Structurally and mag- Cenozoic environmental changes in East Africa with intercalated volcaniclastic deposits that matically controlled processes have created and their influence on mammalian and hominin permit high-precision 40Ar/39Ar age calibra- complex relief and drainage conditions that are evolution (1–3). Because terrestrial records of tion of lake-level highstands (5, 6) (Fig. 2). highly variable over time, beginning at about East African environmental change are typically For rift lakes to form, two basic conditions 45 million years ago (Ma) and continuing into rare, geographically dispersed, and incomplete, have to be satisfied. First, basins defined by the present (7–9). Volcanism and faulting Indian and Atlantic Ocean sediment records have been used to reconstruct climatic changes in the region (3). However, because of the unique tec- AFAR Central Afar tonic and magmatic evolution of the East African BASIN Rift System (EARS) and resulting changes in topography and drainage patterns, marine sed- iment records may not reflect contemporaneous environmental changes in East Africa. It is, there- Ethiopian Rift fore, important to reach a better understanding of the processes changing the habitat of mammals ETHIOPIAN RIFTRIF and hominins before suggesting possible links between climate and faunal changes. WESTERN The Rift Valley lakes are excellent record- 6 BRANCH Omo Areas > 1000 m ers of past climate changes in East Africa (4, 5). OF THE EARS above sea level The western branch of the EARS contains Lake Turkana Normal Fault several large and deep lakes that formed dur- 4 ing the past 10 million years, and a series of EASTERN Turkana small lakes that are presently partly alkaline BRANCH has developed in the eastern branch since the 2°N Suguta Valley OF THE EARS Pliocene (5). The lake history in the Ethiopian, Lake Mt. Elgon KENYA RIFT Kenyan, and Tanzanian rifts is complex and Albert Baringo-Bogoria closely tied to the volcanic and tectonic evo- Nakuru- Equator lution of the area, leading to the formation of Lake Elmenteita Mt. Kenya internally drained basins with fluctuating river Edward Turasha Lake Naivasha TANZANIAN RIFT networks and catchment sizes (5)(Fig.1). Victoria Gicheru Magadi- Indian Ocean Lake Natron Olorgesailie Kivu 1Institut fu¨r Geowissenschaften, Universita¨t Potsdam, Post Office Box 601553, D-14415 Potsdam, Germa- Olduvai Mt. Kilimanjaro ny. 2Environmental Change Research Center, Depart- 30°E 32 34 38 40 42 44 ment of Geography, University College London, UK. 3Berkeley Geochronology Center, 2455 Ridge Road, Fig. 1. Map of East Africa, showing topography, rift faults, and sites of lake sediment sequences Berkeley, CA 94709, USA. discussed in the paper. www.sciencemag.org SCIENCE VOL 309 23 SEPTEMBER 2005 2051 R EPORTS were diachronous and progressed from north to be affected by normal faulting, leading to five major diatomite beds occurs at precession- to south (7–9). In the Ethiopian Rift, volcan- further structural segmentation (4). al intervals, as calibrated by 40Ar/39Ar ages on ism started between 45 and 33 Ma; in north- In contrast, sedimentation in the Tanzanian intercalated ash layers (13). Contemporaneous ern Kenya, it started at about 33 Ma and sector of the rift began within isolated basins at lake deposits from adjacent basins have not continued to about 25 Ma; and the magmatic È5Ma(11). Major normal faulting in the yet been found (14–16). The possibility cannot activity of the central and southern segments Magadi-Natron and Olduvai basins occurred be excluded, however, that sediments of that of the rifts in Kenya and Tanzania started at 1.2 Ma and produced the present-day rift age are buried and downfaulted in the central between 15 and 8 Ma (9). escarpments (11). Late Quaternary structural Kenya Rift. In this area, no evidence for lakes Major faulting in Ethiopia from 20 to 14 Ma en echelon segmentation during WNW-ESE– exists between a 4.7-to-4.3-million-year-old and was followed by the evolution of the Turkana oriented extension created numerous sub-basins È90-m-thick diatomite sequence at Turasha on Rift zone in northern Kenya (9), whereas east- in the individual rift sectors that commonly the Kinangop Plateau and the È1-million-year- dipping faults developed between 12 and 6 Ma hosted smaller lakes (4). The southward prop- old lake deposits at Kariandusi. In contrast, in the Kenya Rift south of 3-N(4, 9). The early agation of rifting, including the formation of diatomitesupto30mthickontheeastern halfgrabens of the Kenya Rift were subsequently faults and magmatic activity, led to the forma- shoulder of the Ethiopian Rift and the Afar faulted antithetically between about 5.5 and 3.7 tion of lake basins in the northern part of the Basin record an important lacustrine period at Ma, generating a full-graben morphology (4). rift. The fluvio-lacustrine deposition within the Gadeb between 2.7 and 2.4 Ma (17). Before the full-graben stage, the large Aberdare Afar, Omo-Turkana, and Baringo-Bogoria After 2 Ma, the sedimentary record be- volcanic complex, with elevation in excess of Basins began in the Middle and Upper Miocene, comes more complete in the eastern branch of 4000 m, developed and is now an important whereas the oldest lacustrine sequences in the the EARS, particularly in the Kenya Rift, and topographic barrier on the eastern shoulder of central and southern segments of the rift in provides strong evidence for several deep lakes the central Kenya Rift (10). By 2.6 Ma, the Kenya and Tanzania are Early Pliocene (5). In between 1.9 and 1.7 Ma. The Plio-Pleistocene central sector was further segmented by west- the following, we provide a compilation of im- Konso-Gardula sedimentary sequence suggests dipping faults, creating the 30-km-wide intrarift portant lake periods in the Ethiopian, Kenyan, that large lakes existed in the southern sector of Kinangop Plateau and the tectonically active and Tanzanian Rifts since the Pliocene (12). the Ethiopian Rift at least temporarily between 40-km-wide inner rift (4). The inner rift was Evidence has been found for deep lakes 1.9 and 1.7 Ma (18). Contemporaneously, sev- subsequently covered by trachytic, basaltic, between 2.7 and 2.5 Ma in the western eral large lakes are also documented in the and rhyolitic lavas and tuffs and continues Baringo-Bogoria Basin, where a sequence of central Afar Basin. Lacustrine deposits are Fig. 2. Compilation of lake and riverine records based on sediment including the Gicheru, Naivasha and Nakuru-Elmenteita Basins, from characteristics and diatom assemblages in the Ethiopian, Kenyan, and (2, 4, 32) and this work; for the Baringo-Bogoria Basin from (13, 33); Tanzanian Rifts. Global climate transitions are from (29–31). Paleo- for the Suguta Basin from (34–36); for the Omo-Turkana Basin from environmental and radiometric age data are given in millions of years (19, 22); for the Ethiopian Rift from (14, 17, 18); and for the Afar Basin for the Olduvai Basin from (20); for the Magadi-Natron and from (14).
Load more

Recommended publications
  • Outcomes of the EU Horizon 2020 DAFNE PROJECT the Omo
    POLICY BRIEF October 2020 Outcomes of the EU Horizon 2020 DAFNE PROJECT The Omo-Turkana River Basin Progress towards cooperative frameworks KEY POLICY MESSAGES The OTB has reached a stage of pivotal importance for future development; the time to establish a cooperative framework on water governance is now. Transparency and accountability must be improved in order to facilitate the sharing of data and information, increasing trust and reducing the perception of risk. Benefit-sharing which extends beyond energy could enhance regional integration and improve sustainable development within the basin . THE OMO-TURKANA RIVER BASIN potential for hydropower and irrigation schemes that are, if scientifically and equitably managed, crucial to lift millions within and outside the basin out of extreme poverty; this has led to transboundary cooperation in recent years. This policy brief is derived from research conducted under the €5.5M four-year EU Horizon 2020 and Swiss funded ‘DAFNE’ project which concerns the promotion of integrated and adaptive water resources management, explicitly addressing the WEF Nexus and aiming to promote a sustainable economy in regions where new infrastructure and expanding The Omo-Turkana River Basin (OTB) – for the agriculture has to be balanced with social, purposes of the DAFNE Project – comprises of economic and environmental needs. The project two main water bodies: the Omo River in takes a multi- and interdisciplinary approach to Ethiopia and Lake Turkana which it drains into. the formation of a decision analytical While the Omo River lies entirely within Ethiopian territory, Lake Turkana is shared by framework (DAF) for participatory and both Kenya and Ethiopia, with the majority of integrated planning, to allow the evaluation of Lake Turkana residing within Kenya.
    [Show full text]
  • Lake Turkana and the Lower Omo the Arid and Semi-Arid Lands Account for 50% of Kenya’S Livestock Production (Snyder, 2006)
    Lake Turkana & the Lower Omo: Hydrological Impacts of Major Dam & Irrigation Development REPORT African Studies Centre Sean Avery (BSc., PhD., C.Eng., C. Env.) © Antonella865 | Dreamstime © Antonella865 Consultant’s email: [email protected] Web: www.watres.com LAKE TURKANA & THE LOWER OMO: HYDROLOGICAL IMPACTS OF MAJOR DAM & IRRIGATION DEVELOPMENTS CONTENTS – VOLUME I REPORT Chapter Description Page EXECUTIVE(SUMMARY ..................................................................................................................................1! 1! INTRODUCTION .................................................................................................................................... 12! 1.1! THE(CONTEXT ........................................................................................................................................ 12! 1.2! THE(ASSIGNMENT .................................................................................................................................. 14! 1.3! METHODOLOGY...................................................................................................................................... 15! 2! DEVELOPMENT(PLANNING(IN(THE(OMO(BASIN ......................................................................... 18! 2.1! INTRODUCTION(AND(SUMMARY(OVERVIEW(OF(FINDINGS................................................................... 18! 2.2! OMO?GIBE(BASIN(MASTER(PLAN(STUDY,(DECEMBER(1996..............................................................19! 2.2.1! OMO'GIBE!BASIN!MASTER!PLAN!'!TERMS!OF!REFERENCE...........................................................................19!
    [Show full text]
  • Lake Turkana National Parks - 2017 Conservation Outlook Assessment (Archived)
    IUCN World Heritage Outlook: https://worldheritageoutlook.iucn.org/ Lake Turkana National Parks - 2017 Conservation Outlook Assessment (archived) IUCN Conservation Outlook Assessment 2017 (archived) Finalised on 26 October 2017 Please note: this is an archived Conservation Outlook Assessment for Lake Turkana National Parks. To access the most up-to-date Conservation Outlook Assessment for this site, please visit https://www.worldheritageoutlook.iucn.org. Lake Turkana National Parks عقوملا تامولعم Country: Kenya Inscribed in: 1997 Criteria: (viii) (x) The most saline of Africa's large lakes, Turkana is an outstanding laboratory for the study of plant and animal communities. The three National Parks serve as a stopover for migrant waterfowl and are major breeding grounds for the Nile crocodile, hippopotamus and a variety of venomous snakes. The Koobi Fora deposits, rich in mammalian, molluscan and other fossil remains, have contributed more to the understanding of paleo-environments than any other site on the continent. © UNESCO صخلملا 2017 Conservation Outlook Critical Lake Turkana’s unique qualities as a large lake in a desert environment are under threat as the demands for water for development escalate and the financial capital to build major dams becomes available. Historically, the lake’s level has been subject to natural fluctuations in response to the vicissitudes of climate, with the inflow of water broadly matching the amount lost through evaporation (as the lake basin has no outflow). The lake’s major source of water, Ethiopia’s Omo River is being developed with a series of major hydropower dams and irrigated agricultural schemes, in particular sugar and other crop plantations.
    [Show full text]
  • Turkana, Kenya): Implications for Local and Regional Stresses
    Research Paper GEOSPHERE Early syn-rift igneous dike patterns, northern Kenya Rift (Turkana, Kenya): Implications for local and regional stresses, GEOSPHERE, v. 16, no. 3 tectonics, and magma-structure interactions https://doi.org/10.1130/GES02107.1 C.K. Morley PTT Exploration and Production, Enco, Soi 11, Vibhavadi-Rangsit Road, 10400, Thailand 25 figures; 2 tables; 1 set of supplemental files CORRESPONDENCE: [email protected] ABSTRACT basins elsewhere in the eastern branch of the East African Rift, which is an active rift, several studies African Rift. (Muirhead et al., 2015; Robertson et al., 2015; Wadge CITATION: Morley, C.K., 2020, Early syn-rift igneous dike patterns, northern Kenya Rift (Turkana, Kenya): Four areas (Loriu, Lojamei, Muranachok-Muru- et al., 2016) have explored interactions between Implications for local and regional stresses, tectonics, angapoi, Kamutile Hills) of well-developed structure and magmatism in the upper crust by and magma-structure interactions: Geosphere, v. 16, Miocene-age dikes in the northern Kenya Rift (Tur- ■ INTRODUCTION investigating stress orientations inferred from no. 3, p. 890–918, https://doi.org /10.1130/GES02107.1. kana, Kenya) have been identified from fieldwork cone lineaments and caldera ellipticity (dikes were Science Editor: David E. Fastovsky and satellite images; in total, >3500 dikes were The geometries of shallow igneous intrusive sys- insufficiently well exposed). Muirhead et al. (2015) Associate Editor: Eric H. Christiansen mapped. Three areas display NNW-SSE– to N-S– tems
    [Show full text]
  • The Politics of the Nile Basin
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Wits Institutional Repository on DSPACE THE POLITICS OF THE NILE BASIN ELIAS ASHEBIR Supervisor:- Larry Benjamin A Dissertation Submitted to the Department of International Relations, at the University of the WitWatersRand, in Partial Fulfillment of the Requirements for Obtaining the Degree of Master of Arts in Hydropotitics Studies Johannesburg 2009 DECLARATION I hereby declare that this dissertation is my own unaided and has not been submitted to any other University for any other degree. Elias Ashebir May 2009 2 TABLE OF CONTENTS Acknowledgment.............................. VI Abstract ................................... VII Introduction................................ VIII Chapter I A Brief Survey of the Nile Basin 1. General overview 1-3 2. Exploration of the Nile 3. Geographical & Hydrological Feature of the Nile Basin 3-4 3.1 The Blue Nile 4 3.2 The White Nile 4-9 Chapter II The Nile Riparian Countries & Future Challenges 1. Subsystems of the Nile Basin 10 1.1 The White Nile Subsystem 11 1.2 The Abbay (Blue Nile) Subsystem 11-12 1.3 The Tekeze (Atbara) Subsystem 12 1.4 The Baro-Akobo (Sobat) Subsystem 12-13 2. General Descriptions of the Nile Riparian Countries 2.1 Upper Riparian Countries of the Nile Basin a) Ethiopia 14-24 b) Eritrea 24-26 c) Kenya 27-32 2.2 The Equatorial upper riparian countries a) Tanzania 32-37 b) Uganda 37-41 c) Democratic Republic of Congo 42-46 3 d) Rwanda 47-50 e) Burundi 50-53 2.3 The Lower riparian countries a) Egypt 53-57 b) Sudan 57-62 Chapter III Legal aspects of the use of the Nile waters 1.
    [Show full text]
  • Case Study: Friends of Lake Turkana
    Case Study: Friends of Lake Turkana Read the passage below. Ikal Angelei, 2012 winner of the prestigious Goldman Environmental Prize, works in the remote Lake Turkana region of Kenya and Ethiopia. Friends of Lake Turkana, a nonprofit organization she founded in 2007, works to stop construction of Ethiopia’s Gilgel Gibe III Dam on the Omo River. The Omo is the major tributary to Lake Turkana, and a dam upstream would drastically impact the lake environment. Changes to the lake’s chemistry and shoreline would devastate the ecology of the region, as well as the local economies that have developed around it, such as fishing, agriculture, and pastoralism. Angelei remembers being shocked on learning of the dam’s likely impact. “At first, I thought, it can’t be real,” she told the New York Times. “I couldn’t imagine the area without the lake.” Geography Located in northern Kenya, the Lake Turkana Basin is a 70,000-square-kilometer (27,027-square- mile) region that is home to Lake Turkana, the most saline lake in East Africa and the largest desert lake in the world. The area includes three national parks: Sibiloi National Park, South Island National Park, and Central Island National Park. Lake Turkana, nicknamed the “Jade Sea” due to its striking color, is a major stopover for migrating waterfowl. The surrounding area is a major breeding ground for Nile crocodiles, hippopotamuses, and a range of venomous snakes. The basin surrounding Lake Turkana is arid and receives little rainfall outside the “long rain” season of March, April, and May.
    [Show full text]
  • The Politics of the Nile Basin
    THE POLITICS OF THE NILE BASIN ELIAS ASHEBIR Supervisor:- Larry Benjamin A Dissertation Submitted to the Department of International Relations, at the University of the WitWatersRand, in Partial Fulfillment of the Requirements for Obtaining the Degree of Master of Arts in Hydropotitics Studies Johannesburg 2009 DECLARATION I hereby declare that this dissertation is my own unaided and has not been submitted to any other University for any other degree. Elias Ashebir May 2009 2 TABLE OF CONTENTS Acknowledgment.............................. VI Abstract ................................... VII Introduction................................ VIII Chapter I A Brief Survey of the Nile Basin 1. General overview 1-3 2. Exploration of the Nile 3. Geographical & Hydrological Feature of the Nile Basin 3-4 3.1 The Blue Nile 4 3.2 The White Nile 4-9 Chapter II The Nile Riparian Countries & Future Challenges 1. Subsystems of the Nile Basin 10 1.1 The White Nile Subsystem 11 1.2 The Abbay (Blue Nile) Subsystem 11-12 1.3 The Tekeze (Atbara) Subsystem 12 1.4 The Baro-Akobo (Sobat) Subsystem 12-13 2. General Descriptions of the Nile Riparian Countries 2.1 Upper Riparian Countries of the Nile Basin a) Ethiopia 14-24 b) Eritrea 24-26 c) Kenya 27-32 2.2 The Equatorial upper riparian countries a) Tanzania 32-37 b) Uganda 37-41 c) Democratic Republic of Congo 42-46 3 d) Rwanda 47-50 e) Burundi 50-53 2.3 The Lower riparian countries a) Egypt 53-57 b) Sudan 57-62 Chapter III Legal aspects of the use of the Nile waters 1. Historical overview of the legal regime in the Nile Basin ..................................
    [Show full text]
  • African Rift Tectonics and Sedimentation, an Introduction H.G
    Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 African Rift tectonics and sedimentation, an introduction H.G. Reading Rifts are one of the most spectacular features of Gulf of Elat rift lies along a lineament that global morphology. Within oceans they separate separates two lithospheric plates and, as Arabia plates as new oceanic crust is created. Within moves northwards relative to the Palestinian continents they may form deep valleys such as the (Mediterranean) block and faults curve or side- Rhine graben, within which runs one of the step each other, extensional pull-apart basins are world's busiest waterways. They are often floored formed, such as the Dead Sea whose surface lies by deep lakes, such as Lake Baikal, the deepest further below sea level than any other place in the lake in the world today whose floor lies 1700 m world. A feature of these strike-slip rift valleys is below the surface of the lake. Ancient rifts are the that the extensional valleys pass, along the rift, sites of petroleum accumulations beneath the into mountainous zones of compression and margins of the Atlantic, in the North Sea and in uplift. Rapid erosion from these mountains leads China, of coals and oil shales and of minerals, to substantial sediment supply for the basins from including phosphates, barite, Cu-Pb-Zn sul- within the fault system itself. Ancient strike-slip phides and uranium (Robbins 1983). Of all the rift basins are therefore characterized by very world's rifts none can match in scale and diversity thick, rapidly accumulated basin fills with areas the Great Rift System, which runs for over of contemporaneous compressional tectonics and 7000 km and includes the East African Rift unconformities not far away.
    [Show full text]
  • Sibiloycentral Island National Parks Kenya
    SIBILOYCENTRAL ISLAND NATIONAL PARKS KENYA SibiloiXentral Island National Parks (Kenya) 73 WORLD HERITAGE NOMINATION-IUCN TECHNICAL EVALUATION SIBILOYCENTRAL ISLAND NATIONAL PARKS (KENYA) 1. DOCUMENTATION (i) IUCNAVCMC Data Sheet (4 references) (ii) Additional Literature Consulted: Feibel, C.S. 1988. Paleoenvironments of the Koobi Fora Formation, Turkana Basin. PhD Dissertation. University of Utah, Department of Geology; Koobi Fora Research Monographs. 1976-97. 5 Vols. Clarendon Press; Leakey, M. and J.M. Harris. 1994. Past Biodiversity in the Turkana Basin. b Conservation of Biodiversity in Africa; Graham. A. and P. Beard. 1975. Eyelids of Morning; Norton-Griffrths, M. 1974. Ecological Survey and Monitoring Project in East Rudolph National Park. 33~. (iii) Consultations: 5 external reviewers, Kenya Wildlife Service and National Museum staff. (iv) Field Visit: J. Thorsell, January, 1997 2. SUMMARY OF NATURAL VALUES Sibiloi National Park (SNP) is 157,085ha in size and is situated on the east shore of Lake Turkana in northern Kenya near the border with Ethiopia. The region is at the western edge of the Somali arid climatic zone. It receives unreliable seasonalrainfall of 25cm per year mostly during March and April. Temperatures range from 26” - 37” with strongly south-easterly winds a persistent feature. The low precipitation and high temperaturescombine to produce moisture deficit resulting in a net evaporation from the lake of 2.5-3m per year. Watercoursesin SNP typically flow on the surface for only a few days in the year. The region is part of the East African Rift System with gently sloping hills and volcanic cones. A large petrified forest is also included in the park.
    [Show full text]
  • State of Conservation Report by The
    1 GOVERNEMTN OF ETHIOPIA STATE PARTY REPORT ON THE STATE OF CONSERVATION OF THE LOWER VALLEY OF THE OMO (Ethiopia) (C 17) IN RESPONSE TO THE WORLD HERITAGE COMMITTEE DECISION WHC37 COM 7B.39 FOR SUMBISSION BY 1 FEBRUARY 2014 2 Contents 1.1 Paragraph 3 ................................................................................................................................... 4 1.2 Paragraph 4 ................................................................................................................................... 4 1.3 Paragraph 5 ................................................................................................................................... 4 1.4 Paragraph 6 ................................................................................................................................... 4 1.5 Paragraph 7 ................................................................................................................................... 4 1.6 Paragraph 8 ................................................................................................................................... 4 1.7 Paragraph 9 ................................................................................................................................... 4 Decision: 37 COM 7B.39............................................................................................................................ 5 Executive Summery ..................................................................................................................................
    [Show full text]
  • Podocarps in Africa: Temperate Zone Relicts Or Rainforest Survivors? Hylton Adie and Michael J
    5 Podocarps in Africa: Temperate Zone Relicts or Rainforest Survivors? Hylton Adie and Michael J. Lawes ABSTRACT. Podocarp distribution in Africa follows a discontinuous mountainous belt from Cameroon to Angola in the west and from Ethiopia in the northeast to the southern Cape in South Africa. Besides a relict population of Afrocarpus falcatus in coastal low- land forest in northeastern South Africa and southern Mozambique, African podocarps are generally limited to highland (Afrotemperate) regions. All podocarps are restricted to montane regions in Madagascar. Afrotemperate landscapes are characterized by a patchy mosaic of forest and grassland. Processes in the matrix, such as fire, are important drivers of forest distribution in the highland regions. Here we examine the relative performance of podocarps and angiosperms along an altitudinal gradient from temperate highlands to subtropical coastal regions in eastern South Africa. Podocarpus latifolius is a success- ful component of temperate highland forest, where it dominates old- growth stages. The success of podocarps is attributed to their greater longevity and ability to regenerate in shade, whereas many potential competing angiosperms are less capable of doing so. Regeneration by P. latifolius and associated angiosperms is less successful in high-light gap environments, where ferns and grasses suppress establishment. Podocarps are rare in coastal scarp forest, where the population is dominated by adult individuals. They are unable to regenerate in very deep shade (<3% daylight), which may account for the lack of P. latifolius regeneration beneath the dense canopy of coastal scarp forest. Low- nutrient soils did not favor podocarps over angiosperms, although the fact that soil nutri- ents do not appear to be limiting and the scarcity of shade- tolerant angiosperms in forests may influence this outcome.
    [Show full text]
  • Oil Governance in Uganda and Kenya a Review of Efforts to Establish Baseline Indicators On
    Oil Governance in Uganda and Kenya: A review of efforts to establish baseline indicators on the impact of the oil sector in Uganda and Kenya © iStock APRIL 2015 The MacArthur Foundation supports creative people and effective institutions committed to building a more just, verdant, and peaceful world. In addition to selecting the MacArthur Fellows, the Foundation works to defend human rights, advance global conservation and security, make cities better places, and understand how technology is affecting children and society. More information is at www.macfound.org. The United Nations Environment Programme World Conservation Monitoring Centre (UNEP- WCMC) is the specialist biodiversity assessment centre of the United Nations Environment Programme (UNEP), the world’s foremost intergovernmental environmental organisation. The Centre has been in operation for over 30 years, combining scientific research with practical policy advice. More information is at www.unep-wcmc.org Copyright: 2015 United Nations Environment Programme Copyright release: This publication may be reproduced for educational or non-profit purposes without special permission, provided acknowledgement to the source is made. Reuse of any figures is subject to permission from the original rights holders. No use of this publication may be made for resale or any other commercial purpose without permission in writing from UNEP. Applications for permission, with a statement of purpose and extent of reproduction, should be sent to the Director, UNEP-WCMC, 219 Huntingdon Road, Cambridge,
    [Show full text]