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Lowland forest collapse and early human impacts at the end of the African Humid Period at Lake Edward, equatorial East Africa

Published online by Cambridge University Press:  24 August 2017

Sarah J. Ivory*
Affiliation:
Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, Rhode Island 02912, USA Department of Earth and Environmental Sciences, University of Kentucky, Lexington, Kentucky 40506, USA
James Russell
Affiliation:
Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, Rhode Island 02912, USA
*
*Corresponding author at: Department of Anthropology, Ohio State University, Columbus, Ohio 43201, USA. E-mail address: [email protected] (S.J. Ivory).

Abstract

In Africa, the early Holocene was characterized by wetter, warmer conditions than today, followed by rapid aridification at ~5.2 ka. However, a lack of lowland vegetation records has prevented a detailed evaluation of forest response to Holocene climate change. Additionally, although modern vegetation communities are linked to human disturbance, few studies have addressed how prehistoric human activities helped engineer the character of modern African ecosystems. Understanding the architecture of lowland and highland forests is important to prevent further degradation from climate/land-use change. We present an 11,000 yr fossil pollen record from Lake Edward, Uganda. We show that Guineo-Congolian forests dominated the highlands and lowlands in equatorial East Africa in the early Holocene, highlighting the importance of rainfall and temperature in controlling forest communities. These forests remained until ~5.2 ka, when the climate became drier. The lacustrine ecosystem response to aridification was abrupt; however, forest decreased gradually, replaced by deciduous woodlands. Woodlands dominated until after an arid period at 2 ka; however, forest did not recover. Increased disturbance indicators and grasses suggest that the arrival of Iron Age people resulted in the modern fire-tolerant vegetation. Although late Holocene climate played a role in vegetation opening, the modern ecosystem architecture in East Africa is linked to early human activities.

Type
Tribute to Daniel Livingstone and Paul Colinvaux
Copyright
Copyright © University of Washington. Published by Cambridge University Press, 2017 

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References

REFERENCES

Beadle, L., 1981. The Inland Waters of Africa: An Introduction to Tropical Limnology. Longman, London.Google Scholar
Berke, M.A., Johnson, T.C., Werne, J.P., Grice, K., Schouten, S., Damsté, J.S.S., 2012. Molecular records of climate variability and vegetation response since the Late Pleistocene in the Lake Victoria basin, East Africa. Quaternary Science Reviews 55, 5974.CrossRefGoogle Scholar
Berke, M.A., Johnson, T.C., Werne, J.P., Livingstone, D.A., Grice, K., Schouten, S., Damste, J.S.S., 2014. Characterization of the last deglacial transition in tropical East Africa: insights from Lake Albert. Palaeogeography, Palaeoclimatology, Palaeoecology 409, 18.CrossRefGoogle Scholar
Beuning, K.R., Russell, J.M., 2004. Vegetation and sedimentation in the Lake Edward basin, Uganda–Congo during the late Pleistocene and early Holocene. Journal of Paleolimnology 32, 118.Google Scholar
Beuning, K.R., Talbot, M.R., Kelts, K., 1997. A revised 30,000-year paleoclimatic and paleohydrologic history of Lake Albert, East Africa. Palaeogeography, Palaeoclimatology, Palaeoecology 136, 259279.Google Scholar
Blaauw, M., Christen, J.A., 2011. Flexible paleoclimate age-depth models using an autoregressive gamma process. Bayesian Analysis 6, 457474.Google Scholar
Bonnefille, R., Riollet, G., 1980. Pollens de savanes d’Afrique orientale. Editions du Centre National de la Recherche Scientifique, Paris.Google Scholar
Bonnefille, R., Riollet, G., 1988. The Kashiru pollen sequence (Burundi) palaeoclimatic implications for the last 40,000 yr B.P. in tropical Africa. Quaternary Research 30, 1935.Google Scholar
Campbell, B.M., 1996. The Miombo in Transition: Woodlands and Welfare in Africa. Center for International Forestry Research, Bogor, Indonesia.Google Scholar
Chase, B.M., Meadows, M.E., Carr, A.S., Reimer, P.J., 2010. Evidence for progressive Holocene aridification in southern Africa recorded in Namibian hyrax middens: implications for African monsoon dynamics and the “African Humid Period. Quaternary Research 74, 3645.CrossRefGoogle Scholar
Coetzee, J.A., 1964. Evidence for a considerable depression of the vegetation belts during the Upper Pleistocene on the East African mountains. Nature 204, 564566.Google Scholar
Costa, K., Russell, J., Konecky, B., Lamb, H., 2014. Isotopic reconstruction of the African Humid Period and Congo Air Boundary migration at Lake Tana, Ethiopia. Quaternary Science Reviews 83, 5867.Google Scholar
Davis, O.K., Shafer, D.S., 2006. Sporormiella fungal spores, a palynological means of detecting herbivore density. Palaeogeography, Palaeoclimatology, Palaeoecology 237, 4050.Google Scholar
DeBusk, G.H., 1997. The distribution of pollen in the surface sediments of Lake Malawi, Africa, and the transport of pollen in large lakes. Review of Palaeobotany and Palynology 97, 123153.CrossRefGoogle Scholar
deMenocal, P., Ortiz, J., Guilderson, T., Adkins, J., Sarnthein, M., Baker, L., Yarusinsky, M., 2000. Abrupt onset and termination of the African Humid Period: rapid climate responses to gradual insolation forcing. Quaternary Science Reviews 19, 347361.CrossRefGoogle Scholar
Faegri, K., Iversen, J., Kaland, P.E., Krzywinski, K., 1989. Textbook of Pollen Analysis. 4th ed. Wiley, Chichester, UK.Google Scholar
Foley, J.A., Coe, M.T., Scheffer, M., Wang, G., 2003. Regime shifts in the Sahara and Sahel: interactions between ecological and climatic systems in northern Africa. Ecosystems 6, 524539.CrossRefGoogle Scholar
Gasse, F., 2000. Hydrological changes in the African tropics since the Last Glacial Maximum. Quaternary Science Reviews 19, 189211.Google Scholar
Gillson, L., 2006. A ‘large infrequent disturbance’ in an East African savanna. African Journal of Ecology 44, 458467.Google Scholar
Goring, S., Williams, J., Blois, J., Jackson, S., Paciorek, C., Booth, R., Marlon, J., Blaauw, M., Christen, J., 2012. Deposition times in the northeastern United States during the Holocene: establishing valid priors for Bayesian age models. Quaternary Science Reviews 48, 5460.Google Scholar
Gowlett, J.A.J., 2016. The discovery of fire by humans: a long and convoluted process. Philosophical Transactions of the Royal Society B: Biological Sciences 371, 20150164. http://dx.doi.org/10.1098/rstb.2015.0164.Google Scholar
Grimm, E.C., 1987. CONISS: a FORTRAN 77 program for stratigraphically constrained cluster analysis by the method of incremental sum of squares. Computers & Geosciences 13, 1335.Google Scholar
Grimm, E.C., 1990. Tilia 2.0. Illinois State Museum. Springfield, Illinois.Google Scholar
Hall, J., Burgess, N.D., Lovett, J., Mbilinyi, B., Gereau, R.E., 2009. Conservation implications of deforestation across an elevational gradient in the Eastern Arc Mountains, Tanzania. Biological Conservation 142, 25102521.Google Scholar
Hastenrath, S., Kutzbach, J.E., 1983. Paleoclimatic estimates from water and energy budgets of East African lakes. Quaternary Research 19, 141153.CrossRefGoogle Scholar
Hély, C., Bremond, L., Alleaume, S., Smith, B., Sykes, M.T., Guiot, J., 2006. Sensitivity of African biomes to changes in the precipitation regime. Global Ecology and Biogeography 15, 258270.Google Scholar
Ivory, S.J., 2013. Vegetation and Climate of the African Tropics for the Last 500,000 Years. PhD dissertation, University of Arizona, Tucson.Google Scholar
Ivory, S.J., Lézine, A.-M., Vincens, A., Cohen, A.S., 2012. Effect of aridity and rainfall seasonality on vegetation in the southern tropics of East Africa during the Pleistocene/Holocene transition. Quaternary Research 77, 7786.Google Scholar
Ivory, S.J., Russell, J., 2016. Climate, herbivory, and fire controls on tropical African forest for the last 60ka. Quaternary Science Reviews 148, 101114.Google Scholar
Jolly, D., Taylor, D., Marchant, R., Hamilton, A., Bonnefille, R., Buchet, G., Riollet, G., 1997. Vegetation dynamics in central Africa since 18,000 yr BP: pollen records from the interlacustrine highlands of Burundi, Rwanda and western Uganda. Journal of Biogeography 24, 492512.Google Scholar
Kendall, R.L., 1969. An ecological history of the Lake Victoria basin. Ecological Monographs 39, 121176.CrossRefGoogle Scholar
Kröpelin, S., Verschuren, D., Lézine, A.-M., Eggermont, H., Cocquyt, C., Francus, P., Cazet, J.-P., Fagot, M., Rumes, B., Russell, J., 2008. Climate-driven ecosystem succession in the Sahara: the past 6000 years. Science 320, 765768.Google Scholar
Lézine, A.-M., 2009. Timing of vegetation changes at the end of the Holocene Humid Period in desert areas at the northern edge of the Atlantic and Indian monsoon systems. Comptes Rendus Geoscience 341, 750759.CrossRefGoogle Scholar
Livingstone, D.A., 1967. Postglacial vegetation of the Ruwenzori Mountains in equatorial Africa. Ecological Monographs 37, 2552.Google Scholar
Livingstone, D.A., 2001. A geological perspective on the conservation of African forests. In: Weber, W. (Ed.), African Rain Forest Ecology and Conservation: An Interdisciplinary Perspective. Yale University Press, New Haven, CT, pp. 5056.Google Scholar
Loomis, S.E., Russell, J.M., Ladd, B., Street-Perrott, F.A., Sinninghe Damsté, J.S., 2012. Calibration and application of the branched GDGT temperature proxy on East African lake sediments. Earth and Planetary Science Letters 357–358, 277288.Google Scholar
Loomis, S.E., Russell, J.M., Verschuren, D., Morrill, C., De Cort, G., Damsté, J.S.S., Olago, D., Eggermont, H., Street-Perrott, F.A., Kelly, M.A., 2017. The tropical lapse rate steepened during the Last Glacial Maximum. Science Advances 3, e1600815. http://dx.doi.org/10.1126/sciadv.1600815.Google Scholar
MacLean, M.R., 1994. Late Stone Age and Early Iron Age settlement in the interlacustrine region: a district case study. Azania: Archaeological Research in Africa 29, 296302.CrossRefGoogle Scholar
Maley, J., 1970. Contributions a l’etude du Bassin tchadien Atlas de pollens du Tchad. Bulletin du Jardin botanique national de Belgique/Bulletin van de Nationale Plantentuin van België 40, 2948.Google Scholar
Marchant, R., Taylor, D., 1998. Dynamics of montane forest in central Africa during the late Holocene: a pollen-based record from western Uganda. Holocene 8, 375381.Google Scholar
McGlue, M.M., Scholz, C.A., Karp, T., Ongodia, B., Lezzar, K.E., 2006. Facies architecture of flexural margin lowstand delta deposits in Lake Edward, East African rift: constraints from seismic reflection imaging. Journal of Sedimentary Research 76, 942958.Google Scholar
Mumbi, C.T., Marchant, R., Hooghiemstra, H., Wooller, M., 2008. Late Quaternary vegetation reconstruction from the Eastern Arc Mountains, Tanzania. Quaternary Research 69, 326341.Google Scholar
Nelson, D.M., Verschuren, D., Urban, M.A., Hu, F.S., 2012. Long‐term variability and rainfall control of savanna fire regimes in equatorial East Africa. Global Change Biology 18, 31603170.Google Scholar
Nicholson, S., 1996. A review of climate dynamics and climate variability in eastern Africa. In: Johnson, T.C., Odada, E.O. (Eds.), The Limnology, Climatology and Paleoclimatology of the East African Lakes. Gordon and Breach, Amsterdam, pp. 2556.Google Scholar
Oksanen, J., Blanchet, F.G., Kindt, R., Legendre, P., Minchin, P.R., O’Hara, R.B., Simpson, G.L., et al., 2016. vegan: Community Ecology Package. R package version 2.3-4 (accessed March 15, 2016). http://CRAN.R-project.org/package=vegan.Google Scholar
Otto-Bliesner, B.L., Russell, J.M., Clark, P.U., Liu, Z., Overpeck, J.T., Konecky, B., deMenocal, P., Nicholson, S.E., He, F., Lu, Z., 2014. Coherent changes of southeastern equatorial and northern African rainfall during the last deglaciation. Science 346, 12231227.Google Scholar
Polhill, R.M., 1966. Ulmaceae. Crown Agents for Oversea Governments and Administrations, London.Google Scholar
Powers, L.A., Johnson, T.C., Werne, J.P., Castaneda, I.S., Hopmans, E.C., Sinninghe Damsté, J.S., Schouten, S., 2005. Large temperature variability in the southern African tropics since the Last Glacial Maximum. Geophysical Research Letters 32, L08706. http://dx.doi.org/10.1029/2004GL022014.Google Scholar
Reimer, P.J., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Bronk Ramsey, C., Buck, C.E., Cheng, H., Edwards, R.L., Friedrich, M., 2013. IntCal13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal BP. Radiocarbon 55, 18691887.Google Scholar
Ritchie, J.C., Eyles, C.H., Haynes, C.V., 1985. Sediment and pollen evidence for an early to mid-Holocene humid period in the eastern Sahara. Nature 314, 352355.Google Scholar
Russell, J.M., Johnson, T.C., 2005. A high-resolution geochemical record from Lake Edward, Uganda Congo and the timing and causes of tropical African drought during the late Holocene. Quaternary Science Reviews 24, 13751389.Google Scholar
Russell, J.M., Johnson, T.C., 2006. The water balance and stable isotope hydrology of Lake Edward, Uganda-Congo. Journal of Great Lakes Research 32, 7790.CrossRefGoogle Scholar
Russell, J.M., Johnson, T.C., Kelts, K.R., Lærdal, T., Talbot, M.R., 2003. An 11 000-year lithostratigraphic and paleohydrologic record from equatorial Africa: Lake Edward, Uganda–Congo. Palaeogeography, Palaeoclimatology, Palaeoecology 193, 2549.Google Scholar
Russell, J.M., Verschuren, D., Eggermont, H., 2007. Spatial complexity of ‘Little Ice Age’ climate in East Africa: sedimentary records from two crater lake basins in western Uganda. Holocene 17, 183193.Google Scholar
Sankaran, M., Hanan, N.P., Scholes, R.J., Ratnam, J., Augustine, D.J., Cade, B.S., Gignoux, J., Higgins, S.I., Le Roux, X., Ludwig, F., 2005. Determinants of woody cover in African savannas. Nature 438, 846849.Google Scholar
Scheffer, M., Carpenter, S., Foley, J.A., Folke, C., Walker, B., 2001. Catastrophic shifts in ecosystems. Nature 413, 591596.CrossRefGoogle ScholarPubMed
Scott, L., Cooremans, B., De Wet, J.S., Vogel, J.C., 1991. Holocene environmental changes in Namibia inferred from pollen analysis of swamp and lake deposits. Holocene 1, 813.Google Scholar
Shanahan, T.M., McKay, N.P., Hughen, K.A., Overpeck, J.T., Otto-Bliesner, B., Heil, C.W., King, J., Scholz, C.A., Peck, J., 2015. The time-transgressive termination of the African Humid Period. Nature Geoscience 8, 140144.Google Scholar
Stewart, B.A., Jones, S.C., 2016. Africa from MIS 6-2: the florescence of modern humans. In: Jones, S.C., Stewart, B.A. (Eds.), Africa from MIS 6-2: Population Dynamics and Paleoenvironments. Springer, Dordrecht, the Netherlands, pp. 120.Google Scholar
Stockmarr, J., 1971. Tablets with spores used in absolute pollen analysis. Pollen et Spores 13, 615621.Google Scholar
Taylor, D., Marchant, R.A., Robertshaw, P., 1999. A sediment-based history of medium altitude forest in central Africa: a record from Kabata Swamp, Ndale volcanic field, Uganda. Journal of Ecology 87, 303315.Google Scholar
Tierney, J.E., Lewis, S.C., Cook, B.I., LeGrande, A.N., Schmidt, G.A., 2011a. Model, proxy and isotopic perspectives on the East African Humid Period. Earth and Planetary Science Letters 307, 103112.Google Scholar
Tierney, J.E., Russell, J.M., Huang, Y., Damsté, J.S.S., Hopmans, E.C., Cohen, A.S., 2008. Northern Hemisphere controls on tropical southeast African climate during the past 60,000 years. Science 322, 252255.CrossRefGoogle ScholarPubMed
Tierney, J.E., Russell, J.M., Sinninghe Damsté, J.S., Huang, Y., Verschuren, D., 2011b. Late Quaternary behavior of the East African monsoon and the importance of the Congo Air Boundary. Quaternary Science Reviews 30, 798807.Google Scholar
Tocheri, M.W., Dommain, R., McFarlin, S.C., Burnett, S.E., Troy Case, D., Orr, C.M., Roach, N.T., et al. 2016. The evolutionary origin and population history of the grauer gorilla. American Journal of Physical Anthropology 159, 418.Google Scholar
Turner, S., Plater, A., 2004. Palynological evidence for the origin and development of late Holocene wetland sediments: Mdlanzi Swamp, KwaZulu-Natal, South Africa. South African Journal of Science 100, 220229.Google Scholar
Tyson, R., 2012. Sedimentary Organic Matter: Organic Facies and Palynofacies. Springer, Dordrecht, the Netherlands.Google Scholar
van Geel, B., Gelorini, V., Lyaruu, A., Aptroot, A., Rucina, S., Marchant, R., Damsté, J.S.S., Verschuren, D., 2011. Diversity and ecology of tropical African fungal spores from a 25,000-year palaeoenvironmental record in southeastern Kenya. Review of Palaeobotany and Palynology 164, 174190.CrossRefGoogle Scholar
Vincens, A., Bremond, L., Brewer, S., Buchet, G., Dussouillez, P., 2006. Modern pollen-based biome reconstructions in East Africa expanded to southern Tanzania. Review of Palaeobotany and Palynology 140, 187212.Google Scholar
Vincens, A., Buchet, G., Servant, M., 2010. Vegetation response to the “African Humid Period” termination in central Cameroon (7° N) – new pollen insight from Lake Mbalang. Climate of the Past 6, 281294.Google Scholar
Vincens, A., Garcin, Y., Buchet, G., 2007. Influence of rainfall seasonality on African lowland vegetation during the Late Quaternary: pollen evidence from Lake Masoko, Tanzania. Journal of Biogeography 34, 12741288.Google Scholar
Washington, R., James, R., Pearce, H., Pokam, W.M., Moufouma-Okia, W., 2013. Congo Basin rainfall climatology: can we believe the climate models? Philosophical Transactions of the Royal Society B: Biological Sciences 368, 20120296. http://dx.doi.org/10.1098/rstb.2012.0296.Google Scholar
Weijers, J.W.H., Schefuß, E., Schouten, S., Damsté, J.S.S., 2007. Coupled thermal and hydrological evolution of tropical Africa over the last deglaciation. Science 315, 17011704.Google Scholar
White, F., 1983. The Vegetation of Africa. Natural Resources Research 20. United Nations Scientific and Cultural Organization, Paris.Google Scholar
Woltering, M., Johnson, T.C., Werne, J.P., Schouten, S., Damsté, J.S.S., 2011. Late Pleistocene temperature history of Southeast Africa: a TEX 86 temperature record from Lake Malawi. Palaeogeography, Palaeoclimatology, Palaeoecology 303, 93102.CrossRefGoogle Scholar
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