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Abstract The scientific contributions of E.M. van Zinderen Bakker (1907–2002) included the introduction of pollen analysis to Quaternary studies in South Africa. His palaeoecological theories evolved while performing palynological research in Southern Africa (the Maluti Mountains, Florisbad, Aliwal North, the Namib Desert), East Africa (Kalambo Falls, Mount Kenya, Cherangani Hills) and on the subantarctic islands (Marion and Prince Edward Islands). He was involved in the first radiocarbon dating from South Africa at Florisbad. Due to quantitative palynological studies he abandoned Wayland's (1929) Pluvial Theory that was generally accepted in the 1960s. He correlated observations of climate changes in Africa to data from marine borehole-cores and climatic fluctuations in the Northern Hemisphere. His observations led to the proposal that global temperature fluctuations are the primary cause of palaeoenvironmental changes. His studies culminated in a conceptual paleoecological model for the Last Glacial Maximum (LGM). Initially he based the model on symmetrical contraction of climatic belts about the equator that shifted the mid-latitude westerly wind system northward to increase the area receiving winter rainfall but later adjusted this by proposing a mechanism of westerly wind system intensification. He suggested that at this time grasslands had spread over wider areas in Southern Africa and that the tropical rain forests in the equatorial region fragmented. For interglacial periods he suggested that a southward shift of the Intertropical Convergence Zone (ITCZ) resulted in widespread humidity in the Congo Basin while large areas of the interior of Southern Africa became arid. Some of his ideas, especially his conceptual models of Quaternary vegetation and climate, are still relevant to the explanation of recent discoveries. [ABSTRACT FROM AUTHOR]

Modern and fossil pollen grains extracted from bat guano in Arnhem Cave are evaluated for their potential as a palynological archive and the possible influence of insectivorous bat behaviour on the pollen contents of their dung. Four out of seven fossil guano samples from this cave were productive. The inconsistent preservation of pollen in bat guano layers may be due to deterioration through various mechanisms, including combustion. The samples that did contain pollen support previous conclusions, derived from pollen in spring deposits, about Holocene palaeoenvironmental changes in central Namibia. Two samples of modern bat dung yielded pollen spectra with a greater proportion of woody plant pollen than grass pollen in comparison with the fossil guano material, indicating denser tree cover than in the past, which may be due to the possible effect of modern farming practices. Differences in the pollen composition in dung of different bat species foraging in a relatively homogenous African savanna suggest that the behaviour of likely bat populations should be accounted for when using bat guano as a palynology source for environmental reconstruction. [ABSTRACT FROM PUBLISHER]

Abstract: Palynological and sedimentological data from a core extracted from Lake Eteza shed new light on the Holocene vegetation and climate history in KwaZulu-Natal and can be linked to regional and global climate change. A 2072cm core with nineteen radiocarbon dates and chronological extrapolation to the bottom of the sequence suggests that sedimentation started ca. 10200calyrsBP. Between ca. 10200 and 6800calyrsBP pollen indicators point to a change from intermediately humid conditions to comparatively drier grassy environments. This is in good agreement with Sea Surface Temperature (SST) fluctuations from a core in the Mozambique Channel which influence precipitation in coastal KwaZulu-Natal, and the beginning of the Holocene Thermal Maximum ca. 10500calyrsBP. The lower section of the core corresponds to gradually increasing Holocene sea levels along the coast and development of freshwater or estuarine conditions at Lake Eteza. The middle Holocene (ca. 6800–3600calyrsBP), when the sea level reached its highest stand and SST peak, indicate humid climatic conditions that favoured an increase of forest trees, e.g. Podocarpus, and undergrowth plants like Issoglossa. As a consequence of higher precipitation and increase of the water table, conditions were favourable for the spread of mangrove, swamp and possibly riverine forest. During the late Holocene after ca. 3600calyrsBP a decrease of Podocarpus and other trees as well as an increase of Chenopodiaceae/Amaranthaceae, grasses and Phoenix coincide with a return to lower sea levels and drier conditions. The decrease of all trees including Phoenix at ca. 700calyrsBP, accompanied by rapid sedimentation rates, possibly reflect forest clearing and upland erosion induced by activities of Iron Age settlers. A dry period at the globally recognized onset of the Little Ice Age might have contributed to these changes. Late Iron Age settlers have probably already introduced Zea mays, which was detected in the profile since ca. 210BP. The appearance of neophytes like Pinus, Casuarina and pollen of Ambrosia-type in the youngest sediments indicates increased disturbance of European settlements and land use since ca. 100calyrsBP. [Copyright &y& Elsevier]

Abstract: The lack of anoxic environments in arid lands makes well-preserved fossil pollen difficult to find. The scarcity of continental palaeobotanical data in tropical arid zones restricts the understanding of aridification processes in these endangered ecosystems. It is essential to improve the knowledge about their environmental histories during the Holocene, and therefore we attempt to investigate the causes and describe the patterns of vegetation change in northern Namibia. With that aim we analyzed pollen from fossil hyrax dung that accumulated over long periods of time by sampling stratigraphically coherent sequences in five radiocarbon-dated middens. The fossil hyrax middens were found in rock shelters on the eastern desert edge in the northwestern Kaokoveld, within the so-called Nama-Karoo biome. This is an ecotonal area between the Namib Desert and the Savanna biomes which reflects features from both systems and its life form composition largely depends on an erratic rainfall pattern. Thirty-three samples were analyzed for pollen and the pollen record reflects a non-continuous vegetation history over the last 5200 yr with a hiatus between ca. 4200 and 1690 yr BP. The pollen spectra reflect arid savanna vegetation with a marked increase in the tree/grass ratio from ca. 1300 cal yr BP. The most likely cause for this change is a decline in moisture that we relate to intrinsic savanna dynamics, with early pastoralism, megahervibore migration and changes in the hyrax diet playing a minor role. [Copyright &y& Elsevier]

New pollen results and radiocarbon dating from fossil hyrax middens derived from the edge of the northern Namib Desert address the shortage of continental palaeobotanical evidence in arid Namibia by providing evidence for the environmental conditions during the mid to late Holocene in the region. The results obtained reflect long-term stability in the area throughout most of the sequence. Higher than modern moisture availability is suggested between c. 6 and 1 ka BP by the increased abundance of Poaceae, Cyperaceae or Chenopodiaceae, which respond rapidly by flowering after modest quantities of rainfall. Around 1 ka and recently arid conditions seem to have prevailed, with a decrease in Poaceae and an increase in Acanthaceae. Other palaeoecological evidence from the local and regional surroundings that focused on fluvial deposits, marine palynology and mineralogy confirms this mid-Holocene increase in more effective rainfall. [ABSTRACT FROM AUTHOR]

Abstract: Pollen was analysed from bat guano from nine caves in southeastern Spain and surface soils in their immediate surroundings. We compare the pollen spectra of 34 modern dung samples from the nine caves with one modern surface pollen sample from each cave. The contents suggest reasonable pollen diversity and richness, including anemophilous and zoophilous pollen types. Since the latter is usually under-represented in atmospheric pollen, the guano spectra therefore appear to reflect the vegetation more effectively than normal surface soil samples. Despite health hazards such as histoplasmosis, the difficulties of obtaining bat guano in deep caves and possible interpretational concerns relating to behaviour and feeding habits of different bat species, this material can be very useful in palaeoecological research provided that the dung was fossilized under favourable environmental conditions that allowed the preservation of pollen. [Copyright &y& Elsevier]

Abstract: The paper presents a sedimentological, palynological, and phytolith record from a 13 m deep Holocene sedimentary sequence, located in the Tsoaing River valley, southwestern Lesotho. Six conventional radiocarbon and two AMS dates provide a relatively high resolution Holocene record for the sedimentary sequence, ranging from ca. 12000 to 4000 years BP. Pollen is absent in the upper section but present in the lower 2 m, confirming terminal Pleistocene/Holocene conditions reported in previous published pollen and charcoal records from the region. The absence of pollen in the upper layers of ca. 9000 years BP and younger suggests that conditions over southwestern Lesotho throughout much of the Holocene was typified by a seasonal climate that prevented long-term preservation of plant remains, although other plant material like robust spores, microscopic charcoal, and phytoliths withstood oxidation. Sedimentological and phytolith results suggest that the period from ca. 8600 to 8450 years BP experienced rapid environmental change towards drier conditions. Phases of chemical disintegration with organic input (including local swamp phytoliths) are suggested at ca. 7000 years BP and again after 4500 years BP. [Copyright &y& Elsevier]

Abstract: Coprolites are often used in African archaeological sites as archives for proxies like pollen, which are trapped and preserved inside them. Investigating pollen taphonomy, here we aim to aid interpretations of local and regional vegetation changes by assessing dietary and other pollen sources of fresh hyaena scats from the Tswalu Kalahari Reserve (TKR, South Africa) and coprolites from Equus Cave (South Africa). Our hypothesis is that the inner and outer fractions of coprolites possibly reflect qualitative and quantitative differences of dispersal factors of pollen taxa during the stages of scat formation influenced by hyaena behaviour and pollen sticking to wet surfaces after defecation. We mechanically separated the inner and outer sections of each scat and coprolite and extracted pollen from both fractions for analyses. The results were associated with vegetation maps of TKR and compared with pollen in modern soils, as controls, and quantitatively analysed in order to test potential differences in quality and richness of pollen between the inner and outer parts of samples. Scats and coprolites seem to be less biased sensors of vegetation than surface soil samples. Further, the inner parts of coprolites and scats provide significantly greater diversity of low pollen-producers including entomophilous types than the outer sections which may typically be biased by wind-transported types and less productive due to pollen loss by weathering. The core fraction might therefore be useful for representing the under-represented taxa in pollen assemblages from the surroundings where hyenas roam. [Copyright &y& Elsevier]

Abstract: The palynology of two overlapping Holocene cores from Lake Sibaya in KwaZulu-Natal elucidates the relationship between climate, vegetation and human impact in the region. By means of twenty-one AMS 14C dates, loss on ignition, and palynological results we established a composite profile. Pollen assemblages include elements of swamp forest (e.g. Rauvolfia, Macaranga), dune forest (e.g. Mimusops), mangrove vegetation (Bruguiera), palmveld (e.g. Phoenix) and bushveld (e.g. Spirostachys, Sclerocarya). Poaceae, aquatics and Cyperaceae are abundant, and fynbos elements like Ericaceae and Restionaceae are rare. Based on comparisons between palynological and archaeological/historical data, the radiocarbon dates seem to show an age error of 50–550 yr, which is probably due to a hardwater reservoir effect. Applying the mean of this error range to our age model suggests that the oldest sediments represent ~6750–7100 cal yr BP, that a >5000 yr hiatus occurs ca. 253 cm depth, and that the upper 253 cm of the composite profile covers the period between ~1300–1500 cal yr BP (~450–650 AD, Early Iron Age), and 2004 AD. The Middle Holocene is characterized by high tree pollen values (especially Phoenix) suggesting warm humid conditions. The Early Iron Age is characterized by high Podocarpus percentages that indicate moist but possibly cooler climatic conditions. The upper part of the pollen sequence is characterized by the decrease of Podocarpus, Isoglossa and Celtis and a rise in Spirostachys. Increasing values of cereal pollen and algae might reflect human activity. Zea mays appears ~150–300 cal yr BP in the pollen sequence according to the radiocarbon chronology and both archaeological and historical evidence. The curve of Pinus pollen rises to 50–70% at the top of the diagram, reflecting the spread of pine plantations since the 1920''s, and Poaceae values decrease. Stoebe and the introduction of neophytes like Ambrosia and Casuarina suggest recent human disturbance. [Copyright &y& Elsevier]

Abstract: High amplitude climate fluctuations have been inferred from marine isotope data in the early Neogene, but few well documented terrestrial records exist from this era to gauge the effects of these high latitude events on continental climates and ecosystems. The extensive, three-dimensional exposures of Miocene fluvial and fluvio-lacustrine sediments in the Rondeberg clay pit near Cape Town provide a unique window on this era. Palaeomagnetic data suggests that the deposits accumulated over a period of <1Ma. The presence of meso-megathermic palynoforms (Palmae, Ilex-type, Euphorb-type, Rhamnaceae) and mesothermic (Podocarpus-type) palynofloras suggests a humid subtropical/tropical climate. However, abundant charcoal, charred in situ tree stumps, overall poor preservation of organics, evidence for upward-drying lacustrine successions and an appreciable fynbos presence, point to cyclical periods of drought. We suggest that these climate fluctuations may have been influenced by the orbital pacing seen in the marine isotope record of the earlier Miocene, pointing to a high latitude link with mid-latitude terrestrial climate patterns. Earlier studies of pollen spectra from the nearby, slightly older Noordhoek deposits show cyclical alternations from tropical to cooler climates and more recent biogeochemical work has shown dramatic coincident fluctuations in depositional temperature. These vegetation changes were previously correlated with major global events embracing the entire Neogene from the Oligo–Miocene (late Oligocene to early Miocene) to the Pliocene. We offer a different interpretation, suggesting that the deposits represent a much shorter time interval in the earlier Miocene and that these climate fluctuations may have been influenced by orbital forcing evinced in the marine isotope record. Along the northern west coast, the Arrisdrift vertebrate fossil assemblage in Early–Middle Miocene terrace deposits of the Orange River indicate a tropical climate but possibly less humid than in the south, with more open vegetation patterns. The presence of pedogenic calcretes and gypcretes in the deposits suggests periodic extremes of aridity not seen in south; the current pronounced north-aridity gradient from humid temperate to hyper-arid may have had its inception in the earlier Miocene. [Copyright &y& Elsevier]