Evidence for a Considerable Depression of the Vegetation Belts during the Upper Pleistocene on the East African Mountains

Coetzee, Johan

doi:10.1038/204564a0

Cited by 88 publications

(64 citation statements)

References 2 publications

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“…Themeda triandra) at the altitude of the present montaneforest (Sacred Lake: Wooller et al, 2000) and subalpine (Lake Rutundu) vegetation belts runs counter to the generally assumed downslope movement of vegetation in response to glacial conditions (Coetzee, 1964(Coetzee, , 1967Flenley, 1979).…”

Section: Late Quaternary Vegetation Distribution Ecology and Ecophysmentioning

confidence: 99%

“…Mount Kenya has been a prominent site for studying changes in tropical vegetation over the last glacial-interglacial transition (Coetzee, 1964(Coetzee, , 1967Street-Perrott et al, 1997;Ficken et al, 1998, 2002Huang et al, 1999Wooller et al, 2000;Barker et al, 2001); a period representing significant changes in water availability, pCO 2 , temperature and disturbance by fires. It has been suggested that last-glacial conditions favoured the spread of C 4 grasses on the mountain (Street-Perrott et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

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Late Quaternary vegetation changes around Lake Rutundu, Mount Kenya, East Africa: evidence from grass cuticles, pollen and stable carbon isotopes

Wooller

Swain

Ficken

et al. 2003

J Quaternary Science

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Woody, subalpine shrubs and grasses currently surround Lake Rutundu, Mount Kenya. Multiple proxies, including carbon isotopes, pollen and grass cuticles, from a 755-cm-long core were used to reconstruct the vegetation over the past 38 300 calendar years. Stable carbon-isotope ratios of total organic carbon and terrestrial biomarkers from the lake sediments imply that the proportion of terrestrial plants using the C 4 photosynthetic pathway was greater during the Late Pleistocene than in the Holocene. Pollen data show that grasses were a major constituent of the vegetation throughout the Late Pleistocene and Holocene. The proportion of grass pollen relative to the pollen from other plants was greatest at the last glacial maximum (LGM). Grass cuticles confirm evidence that C 4 grass taxa were present at the LGM and that the majority followed the cold-tolerant NADP-ME C 4 subpathway.

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Section: Late Quaternary Vegetation Distribution Ecology and Ecophysmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Late Quaternary vegetation changes around Lake Rutundu, Mount Kenya, East Africa: evidence from grass cuticles, pollen and stable carbon isotopes

Wooller

Swain

Ficken

et al. 2003

J Quaternary Science

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“…The first investigations into past ecological change from tropical regions came from Hawaii (Selling 1948), the Andes (van der Hammen and Gonzalez 1960), southern Africa (van Zinderen Bakker and Clark 1962), east Africa (Coetzee 1964), the Galapagos Islands (Colinvaux 1972), the Amazon basin (van der Hammen 1972) and west Africa (Maley and Livingstone 1983). The focus of early studies of fossil pollen from the tropics was on the nature of the past vegetation and the inferences that could be drawn about past climate conditions.…”

mentioning

confidence: 99%

Pollen-vegetation richness and diversity relationships in the tropics

Gosling

Julier

Adu‐Bredu

et al. 2017

Veget Hist Archaeobot

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Tracking changes in biodiversity through time requires an understanding of the relationship between modern diversity and how this diversity is preserved in the fossil record. Fossil pollen is one way in which past vegetation diversity can be reconstructed. However, there is limited understanding of modern pollen-vegetation diversity relationships from biodiverse tropical ecosystems. Here, pollen (palynological) richness and diversity (Hill N 1 ) are compared with vegetation richness and diversity from forest and savannah ecosystems in the New World and Old World tropics (Neotropics and Palaeotropics). Modern pollen data were obtained from artificial pollen traps deployed in 1-ha vegetation study plots from which vegetation inventories had been completed in Bolivia and Ghana. Pollen counts were obtained from 15 to 22 traps per plot, and aggregated pollen sums for each plot were > 2,500. The palynological richness/diversity values from the Neotropics were moist evergreen forest = 86/6.8, semi-deciduous dry forest = 111/21.9, wooded savannah = 138/31.5, and from the Palaeotropics wet evergreen forest = 144/28.3, semi-deciduous moist forest = 104/4.4, forest-savannah transition = 121/14.1; the corresponding vegetation richness/diversity was 100/36.7, 80/38.7 and 71/39.4 (Neotropics), and 101/54.8, 87/45.5 and 71/34.5 (Palaeotropics). No consistent relationship was found between palynological richness/diversity, and plot vegetation richness/diversity, due to the differential influence of other factors such as landscape diversity, pollination strategy, and pollen source area. Palynological richness exceeded vegetation richness, while pollen diversity was lower than vegetation diversity. The relatively high global diversity of tropical vegetation was found to be reflected in the pollen rain.

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“…In equatorial East Africa the extension of montane belts to lower elevation has been known for several decades thanks to geological data on former glaciers and to palynological studies. The principal conclusions were a 5-9 ~ lowering of the temperature during the last cold maximum phase (Coetzee, 1964;Van Zinderen Bakker and Coetzee, 1972;Hamilton, 1973Hamilton, , 1982Flenley, 1979). Moreover, in other parts of equatorial Africa, such as northern Angola (Van Zinderen Bakker and Clark, 1962) and southern Congo Republic (Caratini and Giresse, 1979;Elenga, 1987), other pollen analyses have also clearly shown extensions of montane vegetations to low elevation (Maley, 1987(Maley, , 1989.…”

Section: The Extension Of Montane Vegetation To Lowlandmentioning

confidence: 99%

The African rain forest vegetation and palaeoenvironments during late quaternary

Maley

1991

Climatic Change

176

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This review paper presents first the main pollen results on the vegetation history of the rain forest during the late Quaternary.-The Lake Bosumtwi record (Ghana) shows the disappearance of rain forest from the base of the core (ca. 28 000 yr BP) to ca. 9000 yr BP. During this time interval the vegetation was of montane type with sparse clumps of trees. There is synchronism between montane vegetation disappearance and rain forest reappearance. This phenomenon occurred abruptly around 9000 yr BP.-The Lake Barombi Mbo record (West Cameroon) shows clearly that from ca. 24 000 yr BP until the present time, rain forest persisted with limited variations, and thus, this area represents a refuge area. From these data and other, one concludes that Afromontane vegetation extended to lowland during cool and humid phases.Other palaeoenvironmental data were obtained by diverse geological analyses of the lacustrine sediments. For Bosumtwi, the relatively precise reconstruction of lake-level fluctuations permitted several palaeoclimatic interpretations for the main Holocene phases.For Barombi Mbo, the evolution of total organic carbon (TOC) and total nitrogen (TON) seems to be related mainly to temperature evolution. By comparison with present-day mountain environments, TOC and TON increase in cool environments, but decrease when warmth and humidity increase, as during Holocene time, because the recycling processes speed up in the topsoil. For the same period the alteration of the soils in the catchment produced a strong increase of kaolinite. All these change intervened ca. 9500 yr BP, which is a key date in tropical Africa.In conclusion, climatic correlations between equatorial and dry north tropical Africa illustrate how changes in the forest block must have important effects on adjacent climatic zones.

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Evidence for a Considerable Depression of the Vegetation Belts during the Upper Pleistocene on the East African Mountains

Cited by 88 publications

References 2 publications

Late Quaternary vegetation changes around Lake Rutundu, Mount Kenya, East Africa: evidence from grass cuticles, pollen and stable carbon isotopes

Late Quaternary vegetation changes around Lake Rutundu, Mount Kenya, East Africa: evidence from grass cuticles, pollen and stable carbon isotopes

Pollen-vegetation richness and diversity relationships in the tropics

The African rain forest vegetation and palaeoenvironments during late quaternary

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