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Kotikot SM, Smithwick EAH, Greatrex H. Observations of enhanced rainfall variability in Kenya, East Africa. Sci Rep 2024; 14:12915. [PMID: 38839907 PMCID: PMC11153539 DOI: 10.1038/s41598-024-63786-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Accepted: 06/03/2024] [Indexed: 06/07/2024] Open
Abstract
Understanding local patterns of rainfall variability is of great concern in East Africa, where agricultural productivity is dominantly rainfall dependent. However, East African rainfall climatology is influenced by numerous drivers operating at multiple scales, and local patterns of variability are not adequately understood. Here, we show evidence of substantial variability of local rainfall patterns between 1981 and 2021 at the national and county level in Kenya, East Africa. Results show anomalous patterns of both wetting and drying in both the long and short rainy seasons, with evidence of increased frequency of extreme wet and dry events through time. Observations also indicate that seasonal and intraseasonal variability increased significantly after 2013, coincident with diminished coherence between ENSO (El Nino Southern Oscillation) and rainfall. Increasing frequency and magnitude of rainfall variability suggests increasing need for local-level climate change adaptation strategies.
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Affiliation(s)
- Susan M Kotikot
- Department of Geography, Earth and Environmental Systems Institute, The Pennsylvania State University, University Park, PA, USA.
| | - Erica A H Smithwick
- Department of Geography, Earth and Environmental Systems Institute, The Pennsylvania State University, University Park, PA, USA
| | - Helen Greatrex
- Department of Geography, Department of Statistics, Institute for Computational and Data Sciences, The Pennsylvania State University, University Park, PA, USA
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Hochman A, Shachar N, Gildor H. Unraveling sub-seasonal precipitation variability in the Middle East via Indian Ocean sea surface temperature. Sci Rep 2024; 14:2919. [PMID: 38316906 PMCID: PMC10844372 DOI: 10.1038/s41598-024-53677-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/03/2024] [Indexed: 02/07/2024] Open
Abstract
This study examines sub-seasonal precipitation anomalies, challenging to predict yet vital for society and the environment. Focusing on October, we investigate correlations between the Indian Ocean Dipole Mode Index (DMI), West Tropical Indian Ocean Index (WTIO), and Middle Eastern precipitation. We find robust correlations (~ 0.7), up to a two-month lag, demonstrating strong links between these climate indices and rainfall patterns, potentially suggesting sub-seasonal precipitation predictability. Over the past four decades, DMI and WTIO have shown a significant upward trend of ~ 0.4 °C, intensifying their impact on precipitation dynamics. This trend signifies evolving Indian Ocean climate patterns with potential regional consequences and is projected to continue in the twenty-first century. Significant correlations also emerge between DMI, WTIO, and maximum daily precipitation, highlighting their role in extreme rainfall events. Finally, our study attributes most of October's precipitation variability to Indian Ocean sea surface temperature variations. These temperature anomalies influence the Indian Ocean's Walker circulation, affecting water vapor flux to the Middle East and shaping regional precipitation. Our findings underscore the importance of these indices in understanding and predicting Middle East climate variability, revealing intricate ocean-atmosphere interactions.
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Affiliation(s)
- Assaf Hochman
- Fredy and Nadine Hermann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Noam Shachar
- Fredy and Nadine Hermann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hezi Gildor
- Fredy and Nadine Hermann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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3
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Almar R, Boucharel J, Graffin M, Abessolo GO, Thoumyre G, Papa F, Ranasinghe R, Montano J, Bergsma EWJ, Baba MW, Jin FF. Influence of El Niño on the variability of global shoreline position. Nat Commun 2023; 14:3133. [PMID: 37308517 PMCID: PMC10261116 DOI: 10.1038/s41467-023-38742-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 05/11/2023] [Indexed: 06/14/2023] Open
Abstract
Coastal zones are fragile and complex dynamical systems that are increasingly under threat from the combined effects of anthropogenic pressure and climate change. Using global satellite derived shoreline positions from 1993 to 2019 and a variety of reanalysis products, here we show that shorelines are under the influence of three main drivers: sea-level, ocean waves and river discharge. While sea level directly affects coastal mobility, waves affect both erosion/accretion and total water levels, and rivers affect coastal sediment budgets and salinity-induced water levels. By deriving a conceptual global model that accounts for the influence of dominant modes of climate variability on these drivers, we show that interannual shoreline changes are largely driven by different ENSO regimes and their complex inter-basin teleconnections. Our results provide a new framework for understanding and predicting climate-induced coastal hazards.
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Affiliation(s)
- Rafael Almar
- LEGOS (Université de Toulouse/CNRS/IRD/UPS), Toulouse, France.
| | - Julien Boucharel
- LEGOS (Université de Toulouse/CNRS/IRD/UPS), Toulouse, France.
- Department of atmospheric sciences (University of Hawaii at Manoa), Honolulu, USA.
| | - Marcan Graffin
- LEGOS (Université de Toulouse/CNRS/IRD/UPS), Toulouse, France
| | - Gregoire Ondoa Abessolo
- Ecosystems and Fishery Resources Laboratory, Institute of Fisheries and Aquatic Sciences, University of Douala, Douala, Cameroon
| | | | - Fabrice Papa
- LEGOS (Université de Toulouse/CNRS/IRD/UPS), Toulouse, France
- Universidade de Brasília (UnB), IRD, Instituto de Geociencias, Brasilia, Brazil
| | - Roshanka Ranasinghe
- Department of Coastal and Urban Risk & Resilience, IHE Delft Institute for Water Education, P.O. Box 3015, 2610 DA, Delft, The Netherlands
- Harbour. Coastal and Offshore Engineering, Deltares, PO Box 177, 2600 MH, Delft, The Netherlands
- Water Engineering and Management, Faculty of Engineering Technology, University of Twente, PO Box 217, 7500 AE, Enschede, The Netherlands
| | | | | | - Mohamed Wassim Baba
- Center for Remote Sensing Application (CRSA), Mohammed VI Polytechnic University (UM6P), Ben Guerir, 43150, Morocco
| | - Fei-Fei Jin
- Department of atmospheric sciences (University of Hawaii at Manoa), Honolulu, USA
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Papa F, Crétaux JF, Grippa M, Robert E, Trigg M, Tshimanga RM, Kitambo B, Paris A, Carr A, Fleischmann AS, de Fleury M, Gbetkom PG, Calmettes B, Calmant S. Water Resources in Africa under Global Change: Monitoring Surface Waters from Space. SURVEYS IN GEOPHYSICS 2023; 44:43-93. [PMID: 35462853 PMCID: PMC9019293 DOI: 10.1007/s10712-022-09700-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 03/05/2022] [Indexed: 05/04/2023]
Abstract
ABSTRACT The African continent hosts some of the largest freshwater systems worldwide, characterized by a large distribution and variability of surface waters that play a key role in the water, energy and carbon cycles and are of major importance to the global climate and water resources. Freshwater availability in Africa has now become of major concern under the combined effect of climate change, environmental alterations and anthropogenic pressure. However, the hydrology of the African river basins remains one of the least studied worldwide and a better monitoring and understanding of the hydrological processes across the continent become fundamental. Earth Observation, that offers a cost-effective means for monitoring the terrestrial water cycle, plays a major role in supporting surface hydrology investigations. Remote sensing advances are therefore a game changer to develop comprehensive observing systems to monitor Africa's land water and manage its water resources. Here, we review the achievements of more than three decades of advances using remote sensing to study surface waters in Africa, highlighting the current benefits and difficulties. We show how the availability of a large number of sensors and observations, coupled with models, offers new possibilities to monitor a continent with scarce gauged stations. In the context of upcoming satellite missions dedicated to surface hydrology, such as the Surface Water and Ocean Topography (SWOT), we discuss future opportunities and how the use of remote sensing could benefit scientific and societal applications, such as water resource management, flood risk prevention and environment monitoring under current global change. ARTICLE HIGHLIGHTS The hydrology of African surface water is of global importance, yet it remains poorly monitored and understoodComprehensive review of remote sensing and modeling advances to monitor Africa's surface water and water resourcesFuture opportunities with upcoming satellite missions and to translate scientific advances into societal applications.
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Affiliation(s)
- Fabrice Papa
- LEGOS, Université de Toulouse, IRD, CNES, CNRS, UPS, 31400 Toulouse, France
- Institute of Geosciences, Universidade de Brasília (UnB), 70910-900 Brasília, Brazil
| | | | - Manuela Grippa
- GET, Université de Toulouse, IRD, CNES, CNRS, UPS, 31400 Toulouse, France
| | - Elodie Robert
- LETG, CNRS, Université de Nantes, 44312 Nantes, France
| | - Mark Trigg
- School of Civil Engineering, University of Leeds, Leeds, LS2 9DY United Kingdom
| | - Raphael M. Tshimanga
- Congo Basin Water Resources Research Center (CRREBaC) and Department of Natural Resources Management, University of Kinshasa (UNIKIN), Kinshasa, Democratic Republic of the Congo
| | - Benjamin Kitambo
- LEGOS, Université de Toulouse, IRD, CNES, CNRS, UPS, 31400 Toulouse, France
- Congo Basin Water Resources Research Center (CRREBaC) and Department of Natural Resources Management, University of Kinshasa (UNIKIN), Kinshasa, Democratic Republic of the Congo
- Department of Geology, University of Lubumbashi (UNILU), Route Kasapa, Lubumbashi, Democratic Republic of the Congo
| | - Adrien Paris
- LEGOS, Université de Toulouse, IRD, CNES, CNRS, UPS, 31400 Toulouse, France
- Hydro Matters, 31460 Le Faget, France
| | - Andrew Carr
- School of Civil Engineering, University of Leeds, Leeds, LS2 9DY United Kingdom
| | - Ayan Santos Fleischmann
- Hydraulic Research Institute (IPH), Federal University of Rio Grande do Sul (UFRGS), 91501-970 Porto Alegre, Brazil
- Instituto de Desenvolvimento Sustentável Mamirauá, 69553-225 Tefé, AM Brazil
| | - Mathilde de Fleury
- GET, Université de Toulouse, IRD, CNES, CNRS, UPS, 31400 Toulouse, France
| | | | - Beatriz Calmettes
- Collecte Localisation Satellites (CLS), 31520 Ramonville Saint-Agne, France
| | - Stephane Calmant
- LEGOS, Université de Toulouse, IRD, CNES, CNRS, UPS, 31400 Toulouse, France
- Institute de Recherche pour le Développement (IRD), Cayenne IRD Center, 97323 French Guiana, France
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Remisiewicz M, Underhill LG. Large-Scale Climatic Patterns Have Stronger Carry-Over Effects than Local Temperatures on Spring Phenology of Long-Distance Passerine Migrants between Europe and Africa. Animals (Basel) 2022; 12:ani12131732. [PMID: 35804633 PMCID: PMC9265019 DOI: 10.3390/ani12131732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/30/2022] [Accepted: 07/02/2022] [Indexed: 12/03/2022] Open
Abstract
Simple Summary Spring in Europe has been trending earlier for almost half a century. Long-distance migrant birds, such as the Willow Warbler and Pied Flycatcher, which breed in Europe, have arrived earlier too. It is broadly accepted that warming springs in temperate regions explain the earlier arrival of migrants. However, migration started weeks earlier and thousands of kilometres away. There must be additional cues elsewhere triggering migration. Meteorologists have developed measures of atmospheric circulation which are related to climate variability in wide regions. One of them is the Southern Oscillation Index, which reflects El Niño/La Niña that cause droughts and floods in the southern hemisphere. Other atmospheric circulation patterns, measured by the North Atlantic Oscillation Index and Indian Ocean Dipole, help predict total rainfall for a whole season in various parts of Africa and Europe. Good rains are associated with plant growth and with insect abundance. Insects provide food for most of these migrants. Therefore, this paper asks the question: “Is the timing of arrival of long-distance migrants in spring related to the climates they experience in the places where they are over the year prior to arrival in Europe?” This paper says the answer is “Yes”. Abstract Earlier springs in temperate regions since the 1980s, attributed to climate change, are thought to influence the earlier arrival of long-distance migrant passerines. However, this migration was initiated weeks earlier in Africa, where the Southern Oscillation, Indian Ocean Dipole, North Atlantic Oscillation drive climatic variability, and may additionally influence the migrants. Multiple regressions investigated whether 15 indices of climate in Africa and Europe explained the variability in timing of arrival for seven trans-Saharan migrants. Our response variable was Annual Anomaly (AA), derived from standardized mistnetting from 1982–2021 at Bukowo, Polish Baltic Sea. For each species, the best models explained a considerable part of the annual variation in the timing of spring’s arrival by two to seven climate variables. For five species, the models included variables related to temperature or precipitation in the Sahel. Similarly, the models included variables related to the North Atlantic Oscillation (for four species), Indian Ocean Dipole (three), and Southern Oscillation (three). All included the Scandinavian Pattern in the previous summer. Our conclusion is that climate variables operating on long-distance migrants in the areas where they are present in the preceding year drive the phenological variation of spring migration. These results have implications for our understanding of carry-over effects.
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Affiliation(s)
- Magdalena Remisiewicz
- Bird Migration Research Station, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland
- Department of Biological Sciences, University of Cape Town, Rondebosch, Cape Town 7701, South Africa;
- Correspondence:
| | - Les G. Underhill
- Department of Biological Sciences, University of Cape Town, Rondebosch, Cape Town 7701, South Africa;
- Biodiversity and Development Institute, 25 Old Farm Road, Rondebosch, Cape Town 7700, South Africa
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Abstract
Extreme value theory is a powerful method that is known to provide statistical models for events rarely observed. This paper presents a modelling framework for the maximum rainfall data recorded in Limpopo province, South Africa, from 1960 to 2020. Daily and monthly rainfall data were obtained from the South Africa Weather Service. In this work, the r-largest order statistics modelling approach is used. Yearly blocks were used in fitting a 61 years’ data set. The parameters of the developed models were estimated using the maximum likelihood method. After the suitable model for data was chosen, i.e., GEVDr=8, the 50-year return level was estimated as 368 mm, which means a probability of 0.02 exceeding 368 mm in fifty years in the Thabazimbi area. This study helps decision-makers in government and non-profit organisations improve preparation strategies and build resilience in reducing disasters resulting from extreme weather events such as excessive rainfall.
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Remisiewicz M, Underhill LG. Climate in Africa sequentially shapes spring passage of Willow Warbler Phylloscopus trochilus across the Baltic coast. PeerJ 2022; 10:e12964. [PMID: 35198263 PMCID: PMC8860065 DOI: 10.7717/peerj.12964] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 01/28/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Many migrant birds have been returning to Europe earlier in spring since the 1980s. This has been attributed mostly to an earlier onset of spring in Europe, but we found the timing of Willow Warblers' passage to be influenced by climate indices for Africa as much as those for Europe. Willow Warblers' spring passage through northern Europe involves populations from different wintering quarters in Africa. We therefore expected that migration timing in the early, middle and late periods of spring would be influenced sequentially by climate indices operating in different parts of the winter range. METHODS Using data from daily mistnetting in 1 April-15 May over 1982-2017 at Bukowo (Poland, Baltic Sea coast), we derived an Annual Anomaly (AA, in days) of Willow Warbler spring migration. We decomposed this anomaly into three main periods (1-26 April, 27 April-5 May, 6-15 May); one-third of migrants in each period. We modelled three sequential time series of spring passage using calendar year and 15 large-scale climate indices averaged over the months of Willow Warblers' life stages in the year preceding spring migration as explanatory variables in multiple regression models. Nine climate variables were selected in the best models. We used these nine explanatory variables and calculated their partial correlations in models for nine overlapping sub-periods of AA. The pattern of relationships between AA in these nine sub-periods of spring and the nine climate variables indicated how spring passage had responded to the climate. We recommend this method for the study of birds' phenological responses to climate change. RESULTS The Southern Oscillation Index and Indian Ocean Dipole in Aug-Oct showed large partial correlations early in the passage, then faded in importance. For the Sahel Precipitation Index (PSAH) and Sahel Temperature Anomaly (TSAH) in Aug-Oct partial correlations occurred early then peaked in mid-passage; for PSAH (Nov-March) correlations peaked at the end of passage. NAO and local temperatures (April-May) showed low correlations till late April, which then increased. For the Scandinavian Index (Jun-Jul) partial correlations peaked in mid-passage. Year was not selected in any of the best models, indicating that the climate variables alone accounted for Willow Warblers' multiyear trend towards an earlier spring passage. DISCUSSION Climate indices for southern and eastern Africa dominated relationships in early spring, but western African indices dominated in mid- and late spring. We thus concluded that Willow Warblers wintering in southern and eastern Africa dominated early arrivals, but those from western Africa dominated later. We suggest that drivers of phenological shifts in avian migration are related to changes in climate at remote wintering grounds and at stopovers, operating with climate change in the north, especially for species with complex and long-distance migration patterns.
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Affiliation(s)
- Magdalena Remisiewicz
- Bird Migration Research Station, Faculty of Biology, University of Gdańsk, Wita Stwosza, Poland,Department of Biological Sciences, University of Cape Town, Rondebosch, Cape Town, South Africa
| | - Les G. Underhill
- Department of Biological Sciences, University of Cape Town, Rondebosch, Cape Town, South Africa,Biodiversity and Development Institute, Rondebosch, Cape Town, South Africa
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Uncertainty in Drought Identification Due to Data Choices, and the Value of Triangulation. WATER 2021. [DOI: 10.3390/w13243611] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Droughts are complex and gradually evolving conditions of extreme water deficits which can compromise livelihoods and ecological integrity, especially in fragile arid and semi-arid regions that depend on rainfed farming, such as Kitui West in south-eastern Kenya. Against the background of low ground-station density, 10 gridded rainfall products and four gridded temperature products were used to generate an ensemble of 40 calculations of the Standardized Precipitation Evapotranspiration Index (SPEI) to assess uncertainties in the onset, duration, and magnitude of past droughts. These uncertainties were driven more by variations between the rainfall products than variations between the temperature products. Remaining ambiguities in drought occurrence could be resolved by complementing the quantitative analysis with ground-based information from key informants engaged in disaster relief, effectively formulating an ensemble approach to SPEI-based drought identification to aid decision making. The reported trend towards drier conditions in Eastern Africa was confirmed for Kitui West by the majority of data products, whereby the rainfall effect on those increasingly dry conditions was subtler than just annual and seasonal declines and greater annual variation of rainfall, which requires further investigation. Nevertheless, the effects of increasing droughts are already felt on the ground and warrant decisive action.
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Fjeldså J, Bowie RCK. Evolutionary and Ecological Explanations for the Elevational Flexibility of Several East African Bird Species Complexes. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.768062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Africa’s montane areas are broken up into several large and small units, each isolated as forest-capped “sky islands” in a “sea” of dry lowland savanna. Many elements of their biota, including montane forest birds, are shared across several disjunct mountains, yet it has been difficult to rigorously define an Afromontane forest avifauna, or determine its evolutionary relationships with the birds of the surrounding lowland forests. In order to trace the historical relationship between lowland and highland avifaunas, we review cases of species or groups of closely related species with breeding populations at different elevations, and use phylogeographic methods to explore the historical connections between such populations within the biodiversity hotspot of East Africa. The study reveals several idiosyncratic patterns, but also a prominent number of cases of gene flow between populations in southern areas, mainly around the Malawi Rift, and mountains and coastal forests to the north, close to the equator. This may reflect more continuous past distributions through northern Mozambique and coastal Tanzania, or seasonal migrations between areas with different rainfall regimes. Over time, these distributional dynamics have resulted in a higher persistence of lineages, and an accumulation of forest-dependent lineages within the Eastern Arc Mountains of Tanzania and the northern part of the coastal forest mosaic.
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Salerno J, Stevens FR, Gaughan AE, Hilton T, Bailey K, Bowles T, Cassidy L, Mupeta-Muyamwa P, Biggs D, Pricope N, Mosimane AW, Henry LM, Drake M, Weaver A, Kosmas S, Woodward K, Kolarik N, Hartter J. Wildlife impacts and changing climate pose compounding threats to human food security. Curr Biol 2021; 31:5077-5085.e6. [PMID: 34562383 DOI: 10.1016/j.cub.2021.08.074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/16/2021] [Accepted: 08/31/2021] [Indexed: 11/28/2022]
Abstract
High-level policy debates surrounding elephant management often dominate global conservation headlines, yet realities for people living with wildlife are not adequately incorporated into policymaking or evident in related discourse.1,2 Human health and livelihoods can be severely impacted by wildlife and indirectly by policy outcomes.3 In landscapes where growing human and elephant (Loxodonta spp. and Elephas maximus) populations compete over limited resources, human-elephant conflict causes crop loss, human injury and death, and retaliatory killing of wildlife.4-6 Across Africa, these problems may be increasingly compounded by climate change, which intensifies resource competition and food insecurity.6-9 Here, we examine how human-wildlife impacts interact with climate change and household food insecurity across the Kavango-Zambezi Transfrontier Conservation Area, the world's largest terrestrial transboundary conservation area, spanning five African nations. We use hierarchical Bayesian statistical models to analyze multi-country household data together with longitudinal satellite-based climate measures relevant to rainfed agriculture. We find that crop depredation by wildlife, primarily elephants, impacts 58% of sampled households annually and is associated with significant increases in food insecurity. These wildlife impacts compound effects of changing climate on food insecurity, most notably observed as a 5-day shortening of the rainy season per 10 years across the data record (1981-2018). To advance sustainability goals, global conservation policy must better integrate empirical evidence on the challenges of human-wildlife coexistence into longer term strategies at transboundary scales, specifically in the context of climate change.3,9-11.
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Affiliation(s)
- Jonathan Salerno
- Department of Human Dimensions of Natural Resources, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523-1480, USA.
| | - Forrest R Stevens
- Department of Geographic and Environmental Sciences, University of Louisville, Louisville, KY 40292, USA
| | - Andrea E Gaughan
- Department of Geographic and Environmental Sciences, University of Louisville, Louisville, KY 40292, USA
| | - Tom Hilton
- Department of Human Dimensions of Natural Resources, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523-1480, USA
| | - Karen Bailey
- Environmental Studies Program, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Timothy Bowles
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA 94720, USA
| | - Lin Cassidy
- Okavango Research Institute, University of Botswana, Maun, Botswana
| | | | - Duan Biggs
- School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA; Resilient Conservation, Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia; Department of Conservation Ecology and Entomology, Stellenbosch University, Matieland 7602, South Africa; Centre for Complex Systems in Transition, School of Public Leadership, Stellenbosch University, Stellenbosch 7600, South Africa
| | - Narcisa Pricope
- Department of Earth and Ocean Sciences, University of North Carolina Wilmington, Wilmington, NC 28403, USA
| | - Alfons Wahabe Mosimane
- Multi-Disciplinary Research Centre, University of Namibia, Neudamm Campus, Windhoek, Namibia
| | | | - Michael Drake
- Environmental Studies Program, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Ariel Weaver
- Department of Geographic and Environmental Sciences, University of Louisville, Louisville, KY 40292, USA
| | - Selma Kosmas
- Department of Wildlife Management and Ecotourism, Katima Mulilo Campus, University of Namibia, Windhoek, Namibia
| | - Kyle Woodward
- Department of Earth and Ocean Sciences, University of North Carolina Wilmington, Wilmington, NC 28403, USA
| | - Nicholas Kolarik
- Department of Geographic and Environmental Sciences, University of Louisville, Louisville, KY 40292, USA
| | - Joel Hartter
- Environmental Studies Program, University of Colorado Boulder, Boulder, CO 80303, USA
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Getahun YS, Li MH, Pun IF. Trend and change-point detection analyses of rainfall and temperature over the Awash River basin of Ethiopia. Heliyon 2021; 7:e08024. [PMID: 34589633 PMCID: PMC8461382 DOI: 10.1016/j.heliyon.2021.e08024] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/27/2021] [Accepted: 09/15/2021] [Indexed: 11/30/2022] Open
Abstract
Awash River basin (ARB) as a system is in a state of continuous change that requires successive studies to discern the changes or trends of climatic elements through time due to climate change/variability, and other socio-economical developmental activities in the basin. The livelihood of communities in the ARB is primarily based on rainfall-dependent agriculture. Effects of rainfall anomalies such as reduction of agricultural productivity, water scarcity, and food insecurity are becoming more prevalent in this area. In recent years, ARB has been experiencing more frequent rainfall anomalies that change-point detection test and trend analyses of basin rainfall associated with sea surface temperature is crucial in providing guidance to improve agricultural productivity in ARB. Change-point detection tests such as Pettit's, the von Neumann ratio (VNR), Buishand's range (BR) and standard normal homogeneity (SNH) plus trend analysis Mann-Kendall (MK) test of rainfall and temperature data from 29 meteorological stations in the ARB were carried out from 1986 to 2016. A significant increasing trend of annual and seasonal temperature was found. The temperature change-points for the annual and major rainy season (MRS) were detected in 2001, while for the minor rainy season (mRS) in 1997. A significant decreasing trend, shift, and high variability of rainfall were detected in the downstream part of the ARB. The BR and SNH results showed that the mRS rainfall change-point was in 1998, with a subsequent mean annual decrease of 52.5 mm. The increase (decrease) of rainfall in the annual and MRS was attributable to La Niña (El Niño) events. The significant decreasing trend and change-point of rainfall in the mRS was attributable to the steady warming of the Indian and Atlantic Oceans, local warming, and La Niña events. With this knowledge of the current trends and change-point for rainfall and temperature in the ARB, it is therefore essential that appropriate integrated water management and water-harvesting technologies are established, especially in the downstream areas. Moreover, early detection of El Niño episodes would provide invaluable warning of impending rainfall anomalies in the ARB and would enable better preparations to mitigate its negative effects.
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Affiliation(s)
- Yitea Seneshaw Getahun
- Taiwan International Graduate Program (TIGP), Earth System Science Program, Academia Sinica, Taipei, 115, Taiwan
- Graduate Institute of Hydrological and Oceanic Sciences, National Central University, Taoyuan, 320, Taiwan
- College of Agriculture and Natural Resource Sciences, Debre Berhan University, Debre Berhan, 445, Ethiopia
| | - Ming-Hsu Li
- Graduate Institute of Hydrological and Oceanic Sciences, National Central University, Taoyuan, 320, Taiwan
| | - Iam-Fei Pun
- Graduate Institute of Hydrological and Oceanic Sciences, National Central University, Taoyuan, 320, Taiwan
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Quantifying Land Use Land Cover Changes in the Lake Victoria Basin Using Satellite Remote Sensing: The Trends and Drivers between 1985 and 2014. REMOTE SENSING 2020. [DOI: 10.3390/rs12172829] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Lake Victoria Basin (LVB) is a significant resource for five states within East Africa, which faces major land use land cover changes that threaten ecosystem integrity and ecosystem services derived from the basin’s resources. To assess land use land cover changes between 1985 and 2014, and subsequently determine the trends and drivers of these changes, we used a series of Landsat images and field data obtained from the LVB. Landsat image pre-processing and band combinations were done in ENVI 5.1. A supervised classification was applied on 118 Landsat scenes using the maximum likelihood classifier in ENVI 5.1. The overall accuracy of classified images was computed for the 2014 images using 124 reference data points collected through stratified random sampling. Computations of area under various land cover classes were calculated between the 1985 and 2014 images. We also correlated the area from natural vegetation classes to farmlands and settlements (urban areas) to explore relationships between land use land cover conversions among these classes. Based on our land cover classifications, we obtained overall accuracy of 71% and a moderate Kappa statistic of 0.56. Our results indicate that the LVB has undergone drastic changes in land use land cover, mainly driven by human activities that led to the conversion of forests, woodlands, grasslands, and wetlands to either farmlands or settlements. We conclude that information from this work is useful not only for basin-scale assessments and monitoring of land cover changes but also for targeting, prioritizing, and monitoring of small scale, community led efforts to restore degraded and fragmented areas in the basin. Such efforts could mitigate the loss of ecosystem services previously derived from large contiguous land covers which are no longer tenable to restore. We recommend adoption of a basin scale, operational, Earth observation-based, land use change monitoring framework. Such a framework can facilitate rapid and frequent assessments of gains and losses in specific land cover classes and thus focus strategic interventions in areas experiencing major losses, through mitigation and compensatory approaches.
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Ngongondo C, Zhou Y, Xu CY. Multivariate framework for the assessment of key forcing to Lake Malawi level variations in non-stationary frequency analysis. ENVIRONMENTAL MONITORING AND ASSESSMENT 2020; 192:593. [PMID: 32821968 PMCID: PMC7442765 DOI: 10.1007/s10661-020-08519-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
Lake Malawi in south eastern Africa is a very important freshwater system for the socio-economic development of the riparian countries and communities. The lake has however experienced considerable recession in the levels in recent years. Consequently, frequency analyses of the lake levels premised on time-invariance (or stationarity) in the parameters of the underlying probability distribution functions (pdfs) can no longer be assumed. In this study, the role of hydroclimate forcing factors (rainfall, lake evaporation, and inflowing discharge) and low frequency climate variability indicators (e.g., El Nino Southern Oscillation-ENSO and the Indian Ocean Dipole Mode-IODM) on lake level variations is investigated using a monthly mean lake level dataset from 1899 to 2017. Non-stationarity in the lake levels was tested and confirmed using the Mann-Kendall trend test (α = 0.05 level) for the first moment and the F test for the second moment (α = 0.05 level). Change points in the series were identified using the Mann-Whitney-Pettit test. The study also compared stationary and non-stationary lake level frequency during 1961 to 2004, the common period where data were available for all the forcing factors considered. Annual maximum series (AMS) and peak over threshold (POT) analysis were conducted by fitting various candidate extreme value distributions (EVD) and parameter fitting methods. The Akaike information criteria (AIC), Bayesian information criteria (BIC), deviance information criteria (DIC), and likelihood ratios (RL) served as model evaluation criteria. Under stationary conditions, the AMS when fitted to the generalized extreme value (GEV) distribution with maximum likelihood estimation (MLE) was found to be superior to POT analysis. For the non-stationary models, open water evaporation as a covariate of the lake levels with the GEV and MLE was found to have the most influence on the lake level variations as compared with rainfall, discharge, and the low frequency climatic forcing. The results are very critical in flood zoning especially with various planned infrastructural developments around the lakeshore.
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Affiliation(s)
- Cosmo Ngongondo
- Department of Geography and Earth Sciences, University of Malawi, Chancellor College, P.O. Box 280, Zomba, Malawi.
- Department of Geosciences, University of Oslo, PO Box 1047, Blindern, 0316, Oslo, Norway.
| | - Yanlai Zhou
- Department of Geosciences, University of Oslo, PO Box 1047, Blindern, 0316, Oslo, Norway
| | - Chong-Yu Xu
- Department of Geosciences, University of Oslo, PO Box 1047, Blindern, 0316, Oslo, Norway
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14
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Remisiewicz M, Underhill LG. Climatic variation in Africa and Europe has combined effects on timing of spring migration in a long-distance migrant Willow Warbler Phylloscopus trochilus. PeerJ 2020; 8:e8770. [PMID: 32211237 PMCID: PMC7083157 DOI: 10.7717/peerj.8770] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 02/19/2020] [Indexed: 12/18/2022] Open
Abstract
Background The arrival of many species of migrant passerine in the European spring has shifted earlier over recent decades, attributed to climate change and rising temperatures in Europe and west Africa. Few studies have shown the effects of climate change in both hemispheres though many long-distance migrants use wintering grounds which span Africa. The migrants’ arrival in Europe thus potentially reflects a combination of the conditions they experience across Africa. We examine if the timing of spring migration of a long-distance migrant, the Willow Warbler, is related to large-scale climate indices across Africa and Europe. Methods Using data from daily mistnetting from 1 April to 15 May in 1982–2017 at Bukowo (Poland, Baltic Sea coast), we developed an Annual Anomaly metric (AA, in days) to estimate how early or late Willow Warblers arrive each spring in relation to their multi-year average pattern. The Willow Warblers’ spring passage advanced by 5.4 days over the 36 years. We modelled AA using 14 potential explanatory variables in multiple regression models. The variables were the calendar year and 13 large-scale indices of climate in Africa and Europe averaged over biologically meaningful periods of two to four months during the year before spring migration. Results The best model explained 59% of the variation in AA with seven variables: Northern Atlantic Oscillation (two periods), Indian Ocean Dipole, Southern Oscillation Index, Sahel Precipitation Anomaly, Scandinavian Index and local mean temperatures. The study also confirmed that a long-term trend for Willow Warblers to arrive earlier in spring continued up to 2017. Discussion Our results suggest that the timing of Willow Warbler spring migration at the Baltic Sea coast is related to a summation of the ecological conditions they had encountered over the previous year during breeding, migration south, wintering in Africa and migration north. We suggest these large-scale climate indices reflect ecological drivers for phenological changes in species with complex migration patterns and discuss the ways in which each of the seven climate indices could be related to spring migration at the Baltic Sea coast.
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Affiliation(s)
- Magdalena Remisiewicz
- Bird Migration Research Station, Faculty of Biology, University of Gdańsk, Gdańsk, Poland.,Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Cape Town, South Africa
| | - Les G Underhill
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Cape Town, South Africa.,Biodiversity and Development Institute, Cape Town, South Africa
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Abstract
Annual precipitation inputs to the Lake Mweru basin, Zambia, were computed from historic data and recent gridded data sets to determine historic (1925–2013) changes in lake level and their potential impacts on the important fisheries of the lake. The results highlight a period from the early 1940s to the mid-1960s when interannual variability of inputs doubled. Existing lake level data did not capture this period but they did indicate that levels were positively correlated with precipitation one to three years previously, reflecting the hydrologic storage of the lake, the inflowing Luapula River and the upstream Bangweulu wetland complex. Lag cross-correlations of rainfall to El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole were weak and spatially and temporally discontinuous. The two drivers were generally positively correlated and induced opposing effects upon annual precipitation and lagged lake levels. This correlation became non-significant during the time of high observed interannual variability and basin inputs were prone to the vagaries of either driver independently or reinforcing drought/excess conditions. During times of high flows and persistent elevated lake levels, breeding habitat for fish increased markedly, as did nutrition supplied from the upstream wetlands. High hydrologic storage ensures that lake levels change slowly, despite contemporary precipitation totals. Therefore, good conditions for the growth of fish populations persisted for several years and populations boomed. Statistical models of biological populations indicated that such temporally autocorrelated conditions, combined with abundant habitat and nutrition can lead the “boom and bust” of fish populations witnessed historically in Lake Mweru.
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Does the IOD Independently Influence Seasonal Monsoon Patterns in Northern Ethiopia? ATMOSPHERE 2019. [DOI: 10.3390/atmos10080432] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The dominant large-scale interannual modes in the tropical Pacific and Indian Oceans—El Niño southern oscillation (ENSO) and the Indian Ocean Dipole (IOD)—dominate seasonal rainfall patterns in Ethiopia. However, there is a clear interaction between ENSO and the IOD, and it is unclear whether the IOD has an independent influence on seasonal monsoon patterns in Northern Ethiopia. We use monthly rainfall records from 15 stations from two drought–prone regions in Northern Ethiopia (Afar and Amhara) for the period 1966–2006 to explore relationships between rainfall and circulation patterns and sea surface temperature (SST) anomalies over the tropical Indo-Pacific region. Our analysis confirms that regional summer monsoon (Kiremt) rainfalls in these regions are predominantly modulated by ENSO. Warm and cold ENSO episodes (El Niño/La Nina) are associated with below and above average summer monsoon rainfall, respectively. Lagged relationship between the IOD and Kiremt rainfall shows that positive/negative phases of the IOD are generally conducive to Kiremt rainfall increases/decreases over large parts of Ethiopia. Regression models based on the large-scale circulation indices NINO3.4 and a Dipole Mode Index (DMI)NO-ENSO representing the “ENSO-free IOD” also highlight the role of ENSO. However, the relative-weights for the models with DMINO-ENSO, calculated using Akaike Information Criteria (AIC), were 1.5 and 1.1 times the weights for the ENSO only models for the Afar and Amhara regions, respectively. This suggests that the IOD has an independent regional influence. This is in line with the conception of the IOD as a unique coupled-mode in the tropics, and may have important implications in boosting seasonal forecasting skills in the regions. No statistically significant trends were found in the regional and modeled rainfall time-series.
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Projected Climatic and Hydrologic Changes to Lake Victoria Basin Rivers under Three RCP Emission Scenarios for 2015–2100 and Impacts on the Water Sector. WATER 2019. [DOI: 10.3390/w11071449] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rivers in the Lake Victoria Basin support a multitude of ecosystem services, and the economies of the riparian countries (Kenya, Tanzania, Uganda, Rwanda, and Burundi) rely on their discharge, but projections of their future discharges under various climate change scenarios are not available. Here, we apply Vector Autoregressive Moving Average models with eXogenous variables (VARMAX) statistical models to project hydrological discharge for 23 river catchments for the 2015–2100 period, under three representative concentration pathways (RCPs), namely RCPs 2.6, 4.5, and 8.5. We show an intensification of future annual rainfall by 25% in the eastern and 5–10% in the western part of the basin. At higher emission scenarios, the October to December season receives more rainfall than the March to May season. Temperature projections show a substantial increase in the mean annual minimum temperature by 1.3–4.5 °C and warming in the colder season (June to September) by 1.7–2.9 °C under RCP 4.5 and 4.9 °C under RCP 8.5 by 2085. Variability in future river discharge ranges from 5–267%, increases with emission intensity, and is the highest in rivers in the southern and south eastern parts of the basin. The flow trajectories reveal no systematic trends but suggest marked inter-annual variation, primarily in the timing and magnitude of discharge peaks and lows. The projections imply the need for coordinated transboundary river management in the future.
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Tobolka M, Dylewski L, Wozna JT, Zolnierowicz KM. How weather conditions in non-breeding and breeding grounds affect the phenology and breeding abilities of white storks. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 636:512-518. [PMID: 29709867 DOI: 10.1016/j.scitotenv.2018.04.253] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 04/18/2018] [Accepted: 04/19/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND It has often been suggested that conditions in wintering grounds affect the breeding abilities of migratory birds. This is known as the carry-over effect. Heretofore, many studies have reported the relationship between conditions in wintering grounds, dates of departure from and arrival at breeding grounds, and breeding success. However, very few studies have shown how these conditions affect the capacity of females for egg production. AIMS To describe how conditions in the remote non-breeding areas in Africa affect reproductory abilities of migratory birds breeding in Europe. METHODS We recorded 863 arrival dates for 191 nests (in 2005-16), clutch sizes of 412 clutches, and egg dimensions of 1725 eggs (in 2003-16) of white storks in western Poland. We used generalised climatic indicators such as the Sahel precipitation index (SPI) and Indian Ocean Dipole (IOD) to assess conditions in wintering grounds prior to breeding and precipitation and temperature in breeding grounds during the breeding season. RESULTS The white stork arrived significantly earlier in seasons preceded by a warmer and rainier March, while conditions in Africa did not affect arrival dates. Females laid more (and larger) eggs in seasons preceded by rainier winters in Africa. Breeding success was not affected by conditions in wintering grounds, but only by the weather during breeding season. CONCLUSIONS Conditions in wintering grounds may affect migratory birds, not only in terms of their arrival dates, but rather with respect to females' egg production capacities. Studies on stable isotopes may yield more detailed findings as to how this process takes place.
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Affiliation(s)
- Marcin Tobolka
- Institute of Zoology, Poznań University of Life Sciences, Wojska Polskiego 71C, 60-625 Poznań, Poland.
| | - Lukasz Dylewski
- Institute of Zoology, Poznań University of Life Sciences, Wojska Polskiego 71C, 60-625 Poznań, Poland
| | - Joanna T Wozna
- Institute of Zoology, Poznań University of Life Sciences, Wojska Polskiego 71C, 60-625 Poznań, Poland
| | - Katarzyna M Zolnierowicz
- Institute of Zoology, Poznań University of Life Sciences, Wojska Polskiego 71C, 60-625 Poznań, Poland
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Campos FA, Morris WF, Alberts SC, Altmann J, Brockman DK, Cords M, Pusey A, Stoinski TS, Strier KB, Fedigan LM. Does climate variability influence the demography of wild primates? Evidence from long-term life-history data in seven species. GLOBAL CHANGE BIOLOGY 2017; 23:4907-4921. [PMID: 28589633 DOI: 10.10.1111/gcb.13754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 04/04/2017] [Indexed: 05/21/2023]
Abstract
Earth's rapidly changing climate creates a growing need to understand how demographic processes in natural populations are affected by climate variability, particularly among organisms threatened by extinction. Long-term, large-scale, and cross-taxon studies of vital rate variation in relation to climate variability can be particularly valuable because they can reveal environmental drivers that affect multiple species over extensive regions. Few such data exist for animals with slow life histories, particularly in the tropics, where climate variation over large-scale space is asynchronous. As our closest relatives, nonhuman primates are especially valuable as a resource to understand the roles of climate variability and climate change in human evolutionary history. Here, we provide the first comprehensive investigation of vital rate variation in relation to climate variability among wild primates. We ask whether primates are sensitive to global changes that are universal (e.g., higher temperature, large-scale climate oscillations) or whether they are more sensitive to global change effects that are local (e.g., more rain in some places), which would complicate predictions of how primates in general will respond to climate change. To address these questions, we use a database of long-term life-history data for natural populations of seven primate species that have been studied for 29-52 years to investigate associations between vital rate variation, local climate variability, and global climate oscillations. Associations between vital rates and climate variability varied among species and depended on the time windows considered, highlighting the importance of temporal scale in detection of such effects. We found strong climate signals in the fertility rates of three species. However, survival, which has a greater impact on population growth, was little affected by climate variability. Thus, we found evidence for demographic buffering of life histories, but also evidence of mechanisms by which climate change could affect the fates of wild primates.
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Affiliation(s)
- Fernando A Campos
- Department of Anthropology, Tulane University, New Orleans, LA, USA
- Department of Anthropology, University of Calgary, Calgary, AB, Canada
| | | | - Susan C Alberts
- Department of Biology, Duke University, Durham, NC, USA
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
| | - Jeanne Altmann
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Diane K Brockman
- Department of Anthropology, University of North Carolina, Charlotte, NC, USA
| | - Marina Cords
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA
| | - Anne Pusey
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
| | - Tara S Stoinski
- The Dian Fossey Gorilla Fund International, Atlanta, GA, USA
| | - Karen B Strier
- Department of Anthropology, University of Wisconsin-Madison, Madison, WI, USA
| | - Linda M Fedigan
- Department of Anthropology, University of Calgary, Calgary, AB, Canada
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20
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Campos FA, Morris WF, Alberts SC, Altmann J, Brockman DK, Cords M, Pusey A, Stoinski TS, Strier KB, Fedigan LM. Does climate variability influence the demography of wild primates? Evidence from long-term life-history data in seven species. GLOBAL CHANGE BIOLOGY 2017; 23:4907-4921. [PMID: 28589633 DOI: 10.1111/gcb.13754] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 04/04/2017] [Indexed: 05/22/2023]
Abstract
Earth's rapidly changing climate creates a growing need to understand how demographic processes in natural populations are affected by climate variability, particularly among organisms threatened by extinction. Long-term, large-scale, and cross-taxon studies of vital rate variation in relation to climate variability can be particularly valuable because they can reveal environmental drivers that affect multiple species over extensive regions. Few such data exist for animals with slow life histories, particularly in the tropics, where climate variation over large-scale space is asynchronous. As our closest relatives, nonhuman primates are especially valuable as a resource to understand the roles of climate variability and climate change in human evolutionary history. Here, we provide the first comprehensive investigation of vital rate variation in relation to climate variability among wild primates. We ask whether primates are sensitive to global changes that are universal (e.g., higher temperature, large-scale climate oscillations) or whether they are more sensitive to global change effects that are local (e.g., more rain in some places), which would complicate predictions of how primates in general will respond to climate change. To address these questions, we use a database of long-term life-history data for natural populations of seven primate species that have been studied for 29-52 years to investigate associations between vital rate variation, local climate variability, and global climate oscillations. Associations between vital rates and climate variability varied among species and depended on the time windows considered, highlighting the importance of temporal scale in detection of such effects. We found strong climate signals in the fertility rates of three species. However, survival, which has a greater impact on population growth, was little affected by climate variability. Thus, we found evidence for demographic buffering of life histories, but also evidence of mechanisms by which climate change could affect the fates of wild primates.
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Affiliation(s)
- Fernando A Campos
- Department of Anthropology, Tulane University, New Orleans, LA, USA
- Department of Anthropology, University of Calgary, Calgary, AB, Canada
| | | | - Susan C Alberts
- Department of Biology, Duke University, Durham, NC, USA
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
| | - Jeanne Altmann
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Diane K Brockman
- Department of Anthropology, University of North Carolina, Charlotte, NC, USA
| | - Marina Cords
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA
| | - Anne Pusey
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
| | - Tara S Stoinski
- The Dian Fossey Gorilla Fund International, Atlanta, GA, USA
| | - Karen B Strier
- Department of Anthropology, University of Wisconsin-Madison, Madison, WI, USA
| | - Linda M Fedigan
- Department of Anthropology, University of Calgary, Calgary, AB, Canada
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Courtney Mustaphi CJ, Gajewski K, Marchant R, Rosqvist G. A late Holocene pollen record from proglacial Oblong Tarn, Mount Kenya. PLoS One 2017; 12:e0184925. [PMID: 28926642 PMCID: PMC5604990 DOI: 10.1371/journal.pone.0184925] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 08/31/2017] [Indexed: 11/22/2022] Open
Abstract
High-elevation ecosystems, such as those on Mount Kenya are undergoing significant changes, with accelerated glacial ice losses over the twentieth century creating new space for alpine plants to establish. These ecosystems respond rapidly to climatic variability and within decades of glacial retreat, Afroalpine pioneering taxa stabilize barren land and facilitate soil development, promoting complex patches of alpine vegetation. Periglacial lake sediment records can be used to examine centennial and millennial scale variations in alpine and montane vegetation compositions. Here we present a 5300-year composite pollen record from an alpine tarn (4370 m asl) in the Hausberg Valley of Mount Kenya. Overall, the record shows little apparent variation in the pollen assemblage through time with abundant montane forest taxa derived and transported from mid elevations, notably high abundances of aerophilous Podocarpus pollen. Afroalpine taxa included Alchemilla, Helichrysum and Dendrosenecio-type, reflecting local vegetation cover. Pollen from the ericaceous zone was present throughout the record and Poaceae percentages were high, similar to other high elevation pollen records from eastern Africa. The Oblong Tarn record pollen assemblage composition and abundances of Podocarpus and Poaceae since the late Holocene (~4000 cal yr BP-present) are similar to pollen records from mid-to-high elevation sites of nearby high mountains such as Mount Elgon and Kilimanjaro. These results suggest a significant amount of uphill pollen transport with only minor apparent variation in local taxa. Slight decreasing trends in alpine and ericaceous taxonomic groups show a long-term response to global late Holocene cooling and a step decrease in rate of change estimated from the pollen assemblages at 3100 cal yr BP in response to regional hydroclimatic variability. Changes in the principal component axis scores of the pollen assemblage were coherent with an independent mid-elevation temperature reconstruction, which supported the strong influence of uphill pollen transport from montane forest vegetation and association between temperatures and montane vegetation dynamics. Pollen accumulation rates showed some variability related to minerogenic sediment input to the lake. The Oblong Tarn pollen record provides an indication of long term vegetation change atop Mount Kenya showing some decreases in local alpine and ericaceous taxa from 5300-3100 cal yr BP and minor centennial-scale variability of montane taxa from mid elevation forests. The record highlights potentials, challenges and opportunities for the use of proglacial lacustrine sediment to examine vegetation change on prominent mountain massifs.
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Affiliation(s)
- Colin J. Courtney Mustaphi
- York Institute for Tropical Ecosystems, Environment Department, Wentworth Way, University of York, York, United Kingdom
- Department of Archaeology and Ancient History, Uppsala Universitet, Uppsala, Sweden
| | - Konrad Gajewski
- Laboratory for Paleoclimatology and Climatology, Department of Geography, Environment and Geomatics, University of Ottawa, Ottawa, Canada
| | - Rob Marchant
- York Institute for Tropical Ecosystems, Environment Department, Wentworth Way, University of York, York, United Kingdom
| | - Gunhild Rosqvist
- Institutionen för naturgeografi, Stockholms Universitet, Stockholm, Sweden
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Land Surface Phenology and Seasonality Using Cool Earthlight in Croplands of Eastern Africa and the Linkages to Crop Production. REMOTE SENSING 2017. [DOI: 10.3390/rs9090914] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Prendergast ME, Quintana Morales EM, Crowther A, Horton MC, Boivin NL. Dietary Diversity on the Swahili Coast: The Fauna from Two Zanzibar Trading Locales. INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY 2017; 27:621-637. [PMID: 28979085 PMCID: PMC5599943 DOI: 10.1002/oa.2585] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/26/2017] [Accepted: 02/06/2017] [Indexed: 06/07/2023]
Abstract
Occupants of coastal and island eastern Africa-now known as the 'Swahili coast'-were involved in long-distance trade with the Indian Ocean world during the later first millennium CE. Such exchanges may be traced via the appearance of non-native animals in the archaeofaunal record; additionally, this record reveals daily culinary practises of the members of trading communities and can thus shed light on subsistence technologies and social organisation. Yet despite the potential contributions of faunal data to Swahili coast archaeology, few detailed zooarchaeological studies have been conducted. Here, we present an analysis of faunal remains from new excavations at two coastal Zanzibar trading locales: the small settlement of Fukuchani in the north-west and the larger town of Unguja Ukuu in the south-west. The occurrences of non-native fauna at these sites-Asian black rat (Rattus rattus) and domestic chicken (Gallus gallus), as well as domestic cat (Felis catus)-are among the earliest in eastern Africa. The sites contrast with one another in their emphases on wild and domestic fauna: Fukuchani's inhabitants were economically and socially engaged with the wild terrestrial realm, evidenced not only through diet but also through the burial of a cache of wild bovid metatarsals. In contrast, the town of Unguja Ukuu had a domestic economy reliant on caprine herding, alongside more limited chicken keeping, although hunting or trapping of wild fauna also played an important role. Occupants of both sites were focused on a diversity of near-shore marine resources, with little or no evidence for the kind of venturing into deeper waters that would have required investment in new technologies. Comparisons with contemporaneous sites suggest that some of the patterns at Fukuchani and Unguja Ukuu are not replicated elsewhere. This diversity in early Swahili coast foodways is essential to discussions of the agents engaged in long-distance maritime trade.
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Affiliation(s)
- M. E. Prendergast
- Radcliffe Institute for Advanced StudyHarvard UniversityCambridgeMA02138USA
| | | | - A. Crowther
- School of Social ScienceThe University of QueenslandBrisbaneQueensland4072Australia
| | - M. C. Horton
- Department of Archaeology and AnthropologyUniversity of BristolBristolBS8 1UUUK
| | - N. L. Boivin
- Max Planck Institute for the Science of Human History07745JenaGermany
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Lawson LP, Bates JM, Menegon M, Loader SP. Divergence at the edges: peripatric isolation in the montane spiny throated reed frog complex. BMC Evol Biol 2015; 15:128. [PMID: 26126573 PMCID: PMC4487588 DOI: 10.1186/s12862-015-0384-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 05/20/2015] [Indexed: 11/17/2022] Open
Abstract
Background Peripatric speciation and peripheral isolation have uncertain importance in species accumulation, and are largely overshadowed by assumed dominance of allopatric modes of speciation. Understanding the role of different speciation mechanisms within biodiversity hotspots is central to understanding the generation of biological diversity. Here, we use a phylogeographic analysis of the spiny-throated reed frogs and examine sister pairings with unbalanced current distributional ranges for characteristics of peripatric speciation. We further investigate whether forest/grassland mosaic adapted species are more likely created through peripatric speciation due to instability of this habitat type. Results We reconstructed a multi-locus molecular phylogeny of spiny-throated reed frogs which we then combined with comparative morphologic data to delimit species and analyze historical demographic change; identifying three new species. Three potential peripatric speciation events were identified along with one case of allopatric speciation. Peripatric speciation is supported through uneven potential and realized distributions and uneven population size estimates based on field collections. An associated climate shift was observed in most potentially peripatric splits. Morphological variation was highest in sexually dimorphic traits such as body size and gular shape, but this variation was not limited to peripatric species pairs as hypothesized. The potentially allopatric species pair showed no niche shifts and equivalent effective population sizes, ruling out peripatry in that speciation event. Two major ecological niche shifts were recovered within this radiation, possibly as adaptations to occupy areas of grassland that became more prevalent in the last 5 million years. Restricted and fluctuating grassland mosaics within forests might promote peripatric speciation in the Eastern Arc Biodiversity Hotspot (EABH). Conclusions In our case study, peripatric speciation appears to be an important driver of diversity within the EABH biodiversity hotspot, implying it could be a significant speciation mechanism in highly fragmented ecosystems. Extensive peripatric speciation in this montane archipelago may explain the abundance of discrete lineages within the limited area of the EABH, as inferred in remote island archipelagos. Future phylogenetic studies incorporating demographic and spatial analyses will clarify the role of peripatric speciation in creating biodiversity hotspots. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0384-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lucinda P Lawson
- Committee on Evolutionary Biology, University of Chicago, 1025 E. 57th St. Culver Hall 402, Chicago, IL, 60637, USA. .,Life Sciences, Field Museum of Natural History, 1400 S. Lake Shore Dr., Chicago, IL, 60605, USA. .,Department of Biological Sciences, University of Cincinnati, 614 Rieveschl Hall, Cincinnati, OH, 45220, USA.
| | - John M Bates
- Committee on Evolutionary Biology, University of Chicago, 1025 E. 57th St. Culver Hall 402, Chicago, IL, 60637, USA. .,Life Sciences, Field Museum of Natural History, 1400 S. Lake Shore Dr., Chicago, IL, 60605, USA.
| | - Michele Menegon
- Tropical Biodiversity Section, Science Museo of Trento, Via della Scienza e del lavoro, 38122, Trento, Italy.
| | - Simon P Loader
- Biogeography Research Group, Department of Environmental Sciences, University of Basel, Basel, 4056, Switzerland.
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Lawson LP. Diversification in a biodiversity hot spot: landscape correlates of phylogeographic patterns in the African spotted reed frog. Mol Ecol 2013; 22:1947-60. [DOI: 10.1111/mec.12229] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 12/05/2012] [Accepted: 12/20/2012] [Indexed: 12/25/2022]
Affiliation(s)
- Lucinda P. Lawson
- Committee on Evolutionary Biology; University of Chicago; Chicago IL 60637 USA
- Zoology Department; Field Museum of Natural History; Chicago IL 60605 USA
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Fjeldså J, Bowie RC, Rahbek C. The Role of Mountain Ranges in the Diversification of Birds. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2012. [DOI: 10.1146/annurev-ecolsys-102710-145113] [Citation(s) in RCA: 257] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jon Fjeldså
- Center for Macroecology, Evolution, and Climate, Natural History Museum of Denmark, University of Copenhagen, DK-2100 Copenhagen, Denmark;
| | - Rauri C.K. Bowie
- Museum of Vertebrate Zoology & Department of Integrative Biology, University of California, Berkeley, California 94720;
| | - Carsten Rahbek
- Center for Macroecology, Evolution, and Climate, Department of Biology, University of Copenhagen, DK-2100 Copenhagen, Denmark;
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Blome MW, Cohen AS, Tryon CA, Brooks AS, Russell J. The environmental context for the origins of modern human diversity: A synthesis of regional variability in African climate 150,000–30,000 years ago. J Hum Evol 2012; 62:563-92. [DOI: 10.1016/j.jhevol.2012.01.011] [Citation(s) in RCA: 202] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 12/02/2011] [Accepted: 01/24/2012] [Indexed: 11/27/2022]
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SHEPPARD CRC, ATEWEBERHAN M, BOWEN BW, CARR P, CHEN CA, CLUBBE C, CRAIG MT, EBINGHAUS R, EBLE J, FITZSIMMONS N, GAITHER MR, GAN CH, GOLLOCK M, GUZMAN N, GRAHAM NAJ, HARRIS A, JONES R, KESHAVMURTHY S, KOLDEWEY H, LUNDIN CG, MORTIMER JA, OBURA D, PFEIFFER M, PRICE ARG, PURKIS S, RAINES P, READMAN JW, RIEGL B, ROGERS A, SCHLEYER M, SEAWARD MRD, SHEPPARD ALS, TAMELANDER J, TURNER JR, VISRAM S, VOGLER C, VOGT S, WOLSCHKE H, YANG JMC, YANG SY, YESSON C. Reefs and islands of the Chagos Archipelago, Indian Ocean: why it is the world's largest no-take marine protected area. AQUATIC CONSERVATION : MARINE AND FRESHWATER ECOSYSTEMS 2012; 22:232-261. [PMID: 25505830 PMCID: PMC4260629 DOI: 10.1002/aqc.1248] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The Chagos Archipelago was designated a no-take marine protected area (MPA) in 2010; it covers 550 000 km2, with more than 60 000 km2 shallow limestone platform and reefs. This has doubled the global cover of such MPAs.It contains 25-50% of the Indian Ocean reef area remaining in excellent condition, as well as the world's largest contiguous undamaged reef area. It has suffered from warming episodes, but after the most severe mortality event of 1998, coral cover was restored after 10 years.Coral reef fishes are orders of magnitude more abundant than in other Indian Ocean locations, regardless of whether the latter are fished or protected.Coral diseases are extremely low, and no invasive marine species are known.Genetically, Chagos marine species are part of the Western Indian Ocean, and Chagos serves as a 'stepping-stone' in the ocean.The no-take MPA extends to the 200 nm boundary, and. includes 86 unfished seamounts and 243 deep knolls as well as encompassing important pelagic species.On the larger islands, native plants, coconut crabs, bird and turtle colonies were largely destroyed in plantation times, but several smaller islands are in relatively undamaged state.There are now 10 'important bird areas', coconut crab density is high and numbers of green and hawksbill turtles are recovering.Diego Garcia atoll contains a military facility; this atoll contains one Ramsar site and several 'strict nature reserves'. Pollutant monitoring shows it to be the least polluted inhabited atoll in the world. Today, strict environmental regulations are enforced.Shoreline erosion is significant in many places. Its economic cost in the inhabited part of Diego Garcia is very high, but all islands are vulnerable.Chagos is ideally situated for several monitoring programmes, and use is increasingly being made of the archipelago for this purpose.
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Affiliation(s)
| | - M. ATEWEBERHAN
- School of Life Sciences, University of Warwick, CV4 7AL, UK
| | - B. W. BOWEN
- Hawai’i Institute of Marine Biology, P.O. Box 1346, Kane’ohe, Hawai’i. 96744, USA
| | - P. CARR
- BF BIOT, Diego Garcia, BIOT, BFPO 485, UK
| | - C. A. CHEN
- Biodiversity Research Centre, Academia Sinica, 128 Academia Road, Nankang, Taipei, 115, Taiwan
| | - C. CLUBBE
- Royal Botanic Gardens Kew, Richmond, Surrey TW9 3AB, UK
| | - M. T. CRAIG
- Department of Marine Sciences, University of Puerto Rico, Mayaguez, P.O. Box 9000, Mayaguez, PR 00681
| | - R. EBINGHAUS
- Department for Environmental Chemistry, Helmholtz-Zentrum Geesthacht, Zentrum für Material- und Küstenforschung GmbH, Max-Planck-Straße 1 I 21502, Geesthacht I, Germany
| | - J. EBLE
- Hawai’i Institute of Marine Biology, P.O. Box 1346, Kane’ohe, Hawai’i. 96744, USA
| | - N. FITZSIMMONS
- Institute for Applied Ecology, University of Canberra, ACT 2601, Australia
| | - M. R. GAITHER
- Hawai’i Institute of Marine Biology, P.O. Box 1346, Kane’ohe, Hawai’i. 96744, USA
| | - C-H. GAN
- Biodiversity Research Centre, Academia Sinica, 128 Academia Road, Nankang, Taipei, 115, Taiwan
| | - M. GOLLOCK
- Zoological Society of London, Regents Park, London, NW1 4RY, UK
| | - N. GUZMAN
- Nestor Guzman: NAVFACFE PWD DG Environmental, PSC 466 Box 5, FPO AP, 96595-0005
| | - N. A. J. GRAHAM
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
| | - A. HARRIS
- School of Life Sciences, University of Warwick, CV4 7AL, UK
| | - R. JONES
- Zoological Society of London, Regents Park, London, NW1 4RY, UK
| | - S. KESHAVMURTHY
- Biodiversity Research Centre, Academia Sinica, 128 Academia Road, Nankang, Taipei, 115, Taiwan
| | - H. KOLDEWEY
- Zoological Society of London, Regents Park, London, NW1 4RY, UK
| | - C. G. LUNDIN
- IUCN Marine Programme, Rue Mauverney 28, Gland, 1196, Switzerland
| | - J. A. MORTIMER
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - D. OBURA
- CORDIO East Africa, #9 Kibaki Flats, Kenyatta Beach, Bamburi Beach, P.O.BOX 10135, Mombasa 80101, Kenya
| | - M. PFEIFFER
- RWTH Aachen University, Templergraben 55, 52056 Aachen, Germany
| | - A. R. G. PRICE
- School of Life Sciences, University of Warwick, CV4 7AL, UK
| | - S. PURKIS
- National Coral Reef Institute, Nova Southeastern University, Oceanographic Center, 8000 North Ocean Drive, Dania Beach, FL 33004, USA
| | - P. RAINES
- Coral Cay Conservation, Elizabeth House, 39 York Road, London SE1 7NQ, UK
| | - J. W. READMAN
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK
| | - B. RIEGL
- National Coral Reef Institute, Nova Southeastern University, Oceanographic Center, 8000 North Ocean Drive, Dania Beach, FL 33004, USA
| | - A. ROGERS
- Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK
| | - M. SCHLEYER
- Oceanographic Research Institute, PO Box 10712, Marine Parade, Durban, 4056, South Africa
| | - M. R. D SEAWARD
- Division of Archaeological, Geographical and Environmental Sciences, University of Bradford, Bradford, West Yorkshire BD7 1DP, UK
| | | | - J. TAMELANDER
- UNEP Division of Environmental Policy Implementation, UN, Rajdamnern Nok Av., Bangkok, 10200, Thailand
| | - J. R. TURNER
- School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5AB, UK
| | - S. VISRAM
- Biodiversity Research Centre, Academia Sinica, 128 Academia Road, Nankang, Taipei, 115, Taiwan
| | - C. VOGLER
- Department für Geo- und Umweltwissenschaften Paläontologie & Geobiologie, Ludwig- Maximilians-Universität, Richard-Wagner-Str.10, 80333, München, Germany
| | - S. VOGT
- Naval Facilities Engineering Command Far East, PSC 473, Box 1, FPO AP 96349, USA
| | - H. WOLSCHKE
- Department for Environmental Chemistry, Helmholtz-Zentrum Geesthacht, Zentrum für Material- und Küstenforschung GmbH, Max-Planck-Straße 1 I 21502, Geesthacht I, Germany
| | - J. M-C. YANG
- Biodiversity Research Centre, Academia Sinica, 128 Academia Road, Nankang, Taipei, 115, Taiwan
| | - S-Y. YANG
- Biodiversity Research Centre, Academia Sinica, 128 Academia Road, Nankang, Taipei, 115, Taiwan
| | - C. YESSON
- Zoological Society of London, Regents Park, London, NW1 4RY, UK
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Fuchs J, Fjeldså J, Bowie RCK. Diversification across an altitudinal gradient in the Tiny Greenbul (Phyllastrephus debilis) from the Eastern Arc Mountains of Africa. BMC Evol Biol 2011; 11:117. [PMID: 21539741 PMCID: PMC3097164 DOI: 10.1186/1471-2148-11-117] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 05/03/2011] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND The Eastern Arc Mountains of Africa have become one of the focal systems with which to explore the patterns and mechanisms of diversification among montane species and populations. One unresolved question is the extent to which populations inhabiting montane forest interact with those of adjacent lowland forest abutting the coast of eastern Africa. The Tiny Greenbul (Phyllastephus debilis) represents the only described bird species within the Eastern Arc/coastal forest mosaic, which is polytypic across an altitudinal gradient: the subspecies albigula (green head) is distributed in the montane Usambara and Nguru Mountains whereas the subspecies rabai (grey head) is found in Tanzanian lowland and foothill forest. Using a combination of morphological and genetic data, we aim to establish if the pattern of morphological differentiation in the Tiny Greenbul (Phyllastrephus debilis) is the result of disruptive selection along an altitudinal gradient or a consequence of secondary contact following population expansion of two differentiated lineages. RESULTS We found significant biometric differences between the lowland (rabai) and montane (albigula) populations in Tanzania. The differences in shape are coupled with discrete differences in the coloration of the underparts. Using multi-locus data gathered from 124 individuals, we show that lowland and montane birds form two distinct genetic lineages. The divergence between the two forms occurred between 2.4 and 3.1 Myrs ago.Our coalescent analyses suggest that limited gene flow, mostly from the subspecies rabai to albigula, is taking place at three mid-altitude localities, where lowland and montane rainforest directly abut. The extent of this introgression appears to be limited and is likely a consequence of the recent expansion of rabai further inland. CONCLUSION The clear altitudinal segregation in morphology found within the Tiny Greenbul is the result of secondary contact of two highly differentiated lineages rather than disruptive selection in plumage pattern across an altitudinal gradient. Based on our results, we recommend albigula be elevated to species rank.
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Affiliation(s)
- Jérôme Fuchs
- Museum of Vertebrate Zoology and Department of Integrative Biology, 3101 Valley Life Science Building, University of California, Berkeley, CA 94720-3160, USA.
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Marshal JP, Owen-Smith N, Whyte IJ, Stenseth NC. The role of El Niño-Southern Oscillation in the dynamics of a savanna large herbivore population. OIKOS 2011. [DOI: 10.1111/j.1600-0706.2010.19155.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Robin VV, Sinha A, Ramakrishnan U. Ancient geographical gaps and paleo-climate shape the phylogeography of an endemic bird in the sky islands of southern India. PLoS One 2010; 5:e13321. [PMID: 20967202 PMCID: PMC2954160 DOI: 10.1371/journal.pone.0013321] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 09/13/2010] [Indexed: 11/21/2022] Open
Abstract
Background Sky islands, formed by the highest reaches of mountain tracts physically isolated from one another, represent one of the biodiversity-rich regions of the world. Comparative studies of geographically isolated populations on such islands can provide valuable insights into the biogeography and evolution of species on these islands. The Western Ghats mountains of southern India form a sky island system, where the relationship between the island structure and the evolution of its species remains virtually unknown despite a few population genetic studies. Methods and Principal Findings We investigated how ancient geographic gaps and glacial cycles have partitioned genetic variation in modern populations of a threatened endemic bird, the White-bellied Shortwing Brachypteryx major, across the montane Shola forests on these islands and also inferred its evolutionary history. We used Bayesian and maximum likelihood-based phylogenetic and population-genetic analyses on data from three mitochondrial markers and one nuclear marker (totally 2594 bp) obtained from 33 White-bellied Shortwing individuals across five islands. Genetic differentiation between populations of the species correlated with the locations of deep valleys in the Western Ghats but not with geographical distance between these populations. All populations revealed demographic histories consistent with population founding and expansion during the Last Glacial Maximum. Given the level of genetic differentiation north and south of the Palghat Gap, we suggest that these populations be considered two different taxonomic species. Conclusions and Significance Our results show that the physiography and paleo-climate of this region historically resulted in multiple glacial refugia that may have subsequently driven the evolutionary history and current population structure of this bird. The first avian genetic study from this biodiversity hotspot, our results provide insights into processes that may have impacted the speciation and evolution of the endemic fauna of this region.
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Affiliation(s)
- V V Robin
- National Institute of Advanced Studies, Indian Institute of Science Campus, Bangalore, India.
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LAWSON LUCINDAP. The discordance of diversification: evolution in the tropical-montane frogs of the Eastern Arc Mountains of Tanzania. Mol Ecol 2010; 19:4046-60. [DOI: 10.1111/j.1365-294x.2010.04788.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Platts PJ, Ahrends A, Gereau RE, McClean CJ, Lovett JC, Marshall AR, Pellikka PKE, Mulligan M, Fanning E, Marchant R. Can distribution models help refine inventory-based estimates of conservation priority? A case study in the Eastern Arc forests of Tanzania and Kenya. DIVERS DISTRIB 2010. [DOI: 10.1111/j.1472-4642.2010.00668.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Conte CA. Forest History in East Africa's Eastern Arc Mountains: Biological Science and the Uses of History. Bioscience 2010. [DOI: 10.1525/bio.2010.60.4.9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Hušek J, Adamĺk P, Cepák J, Tryjanowski P. The Influence of Climate and Population Size on the Distribution of Breeding Dates in the Red-Backed Shrike (Lanius collurio). ANN ZOOL FENN 2009. [DOI: 10.5735/086.046.0605] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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The Indian Ocean Dipole and malaria risk in the highlands of western Kenya. Proc Natl Acad Sci U S A 2009; 106:1857-62. [PMID: 19174522 DOI: 10.1073/pnas.0806544106] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Epidemics of malaria in the East African highlands in the last 2 decades have often been associated with climate variability, particularly the El Niño-Southern Oscillation (ENSO). However, there are other factors associated with malaria risk and there is increased interest in the influences of the Indian Ocean Dipole (IOD), a climate mode of coupled ocean-atmosphere variability, on East African rainfall. This study explores the relationship between IOD and the number of malaria patients in 7 hospitals from 2 districts in the western Kenyan highlands, controlling for the effects of ENSO. We examined temporal patterns (1982-2001) in the number of malaria cases in relation to the dipole mode index (DMI), defined as the difference in sea surface temperature anomaly between the western (10 degrees S-10 degrees N, 50 degrees-70 degrees E) and eastern (10 degrees S-0 degrees, 90 degrees-110 degrees E) tropical Indian Ocean. We used Poisson regression models, adjusted for ENSO index Niño 3 region (NINO3), seasonal and interannual variations. The number of malaria patients per month increased by 3.4%-17.9% for each 0.1 increase above a DMI threshold (3-4 months lag). Malaria cases increased by 1.4%-10.7% per month, for each 10 mm increase in monthly rainfall (2-3 months lag). In 6 of 7 places, there was no evidence of an association between NINO3 and the number of malaria cases after adjusting for the effect of DMI. This study suggests that the number of malaria cases in the western Kenyan highlands increases with high DMI in the months preceding hospital visits.
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Couvreur TLP, Chatrou LW, Sosef MSM, Richardson JE. Molecular phylogenetics reveal multiple tertiary vicariance origins of the African rain forest trees. BMC Biol 2008; 6:54. [PMID: 19087283 PMCID: PMC2628871 DOI: 10.1186/1741-7007-6-54] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Accepted: 12/16/2008] [Indexed: 11/12/2022] Open
Abstract
Background Tropical rain forests are the most diverse terrestrial ecosystems on the planet. How this diversity evolved remains largely unexplained. In Africa, rain forests are situated in two geographically isolated regions: the West-Central Guineo-Congolian region and the coastal and montane regions of East Africa. These regions have strong floristic affinities with each other, suggesting a former connection via an Eocene pan-African rain forest. High levels of endemism observed in both regions have been hypothesized to be the result of either 1) a single break-up followed by a long isolation or 2) multiple fragmentation and reconnection since the Oligocene. To test these hypotheses the evolutionary history of endemic taxa within a rain forest restricted African lineage of the plant family Annonaceae was studied. Molecular phylogenies and divergence dates were estimated using a Bayesian relaxed uncorrelated molecular clock assumption accounting for both calibration and phylogenetic uncertainties. Results Our results provide strong evidence that East African endemic lineages of Annonaceae have multiple origins dated to significantly different times spanning the Oligocene and Miocene epochs. Moreover, these successive origins (c. 33, 16 and 8 million years – Myr) coincide with known periods of aridification and geological activity in Africa that would have recurrently isolated the Guineo-Congolian rain forest from the East African one. All East African taxa were found to have diversified prior to Pleistocene times. Conclusion Molecular phylogenetic dating analyses of this large pan-African clade of Annonaceae unravels an interesting pattern of diversification for rain forest restricted trees co-occurring in West/Central and East African rain forests. Our results suggest that repeated reconnections between the West/Central and East African rain forest blocks allowed for biotic exchange while the break-ups induced speciation via vicariance, enhancing the levels of endemicity. These results provide an explanation for present day distribution patterns and origins of endemicity for African rain forest trees. Moreover, given the pre-Pleistocene origins of all the studied endemic East African genera and species, these results also offer important insights for setting conservation priorities in these highly diversified but threatened ecosystems.
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Affiliation(s)
- Thomas L P Couvreur
- Nationaal Herbarium Nederland, Wageningen branch, Biosystematics Group, Wageningen University, Wageningen, The Netherlands.
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Platts PJ, McClean CJ, Lovett JC, Marchant R. Predicting tree distributions in an East African biodiversity hotspot: model selection, data bias and envelope uncertainty. Ecol Modell 2008. [DOI: 10.1016/j.ecolmodel.2008.06.028] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Minakawa N, Sonye G, Dida GO, Futami K, Kaneko S. Recent reduction in the water level of Lake Victoria has created more habitats for Anopheles funestus. Malar J 2008; 7:119. [PMID: 18598355 PMCID: PMC2490699 DOI: 10.1186/1475-2875-7-119] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Accepted: 07/03/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The water level of Lake Victoria has fallen more than 1.5 m since 1998, revealing a narrow strip of land along the shore. This study determined whether the recent drop in the water level has created additional breeding grounds for malaria vectors. METHODS The recent and past shorelines were estimated using landmarks and a satellite image. The locations of breeding habitats were recorded using a GPS unit during the high and low lake water periods. GIS was used to determine whether the breeding habitats were located on newly emerged land between the new and old shorelines. RESULTS Over half of the breeding habitats existed on newly emerged land. Fewer habitats for the Anopheles gambiae complex were found during the low water level period compared to the high water period. However, more habitats for Anopheles funestus were found during the high water level period, and they were all located on the newly emerged land. CONCLUSION The recent reduction in water level of Lake Victoria has increased the amount of available habitat for A. funestus. The results suggest that the water drop has substantially affected the population of this malaria vector in the Lake Victoria basin, particularly because the lake has a long shoreline that may harbour many new breeding habitats.
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Affiliation(s)
- Noboru Minakawa
- Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
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