A Holocene sequence of vegetation change at Lake Eteza, coastal KwaZulu-Natal, South Africa

Review of Palaeobotany and Palynology 162 (2010) 39–53

Contents lists available at ScienceDirect

Review of Palaeobotany and Palynology

j ourna l homepage: www.e lsev ie r.com/ locate / revpa lbo

A Holocene sequence of vegetation change at Lake Eteza, coastal KwaZulu-Natal,South Africa

Frank H. Neumann a,b,c,⁎, Louis Scott b, C.B. Bousman d,e, L. van As f

a Bernard Price Institute for Palaeontology, University of the Witwatersrand, Private Bag 3, Wits 2050 (Johannesburg), South Africab Department of Plant Sciences, University of the Free State, P.O. Box 339, Bloemfontein 9300, South Africac Steinmann-Institut für Geologie, Mineralogie und Paläontologie, Nussallee 8, 53115 Bonn, Germanyd Department of Anthropology and Center for Archaeological Studies, Texas State University—San Marcos, San Marcos, Texas 78666, USAe School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg 2050, South Africaf Department of Zoology and Entomology, University of the Free State, P.O. Box 339, Bloemfontein 9300, South Africa

⁎ Corresponding author. Department of Plant Sciences,Box 339, Bloemfontein 9300, South Africa.

E-mail address: [email protected] (F.H. Neum

0034-6667/$ – see front matter © 2010 Elsevier B.V. Aldoi:10.1016/j.revpalbo.2010.05.001

a b s t r a c t
a r t i c l e i n f o
Article history:Received 11 December 2009Received in revised form 30 April 2010Accepted 7 May 2010Available online 17 May 2010

Keywords:forest reconstructionvegetation historySouthern HemisphereAfrican coasthuman impact

Palynological and sedimentological data from a core extracted from Lake Eteza shed new light on theHolocene vegetation and climate history in KwaZulu-Natal and can be linked to regional and global climatechange. A 2072 cm core with nineteen radiocarbon dates and chronological extrapolation to the bottom ofthe sequence suggests that sedimentation started ca. 10200 cal yrs BP. Between ca. 10200 and6800 cal yrs BP pollen indicators point to a change from intermediately humid conditions to comparativelydrier grassy environments. This is in good agreement with Sea Surface Temperature (SST) fluctuations from acore in the Mozambique Channel which influence precipitation in coastal KwaZulu-Natal, and the beginningof the Holocene Thermal Maximum ca. 10500 cal yrs BP. The lower section of the core corresponds togradually increasing Holocene sea levels along the coast and development of freshwater or estuarineconditions at Lake Eteza. The middle Holocene (ca. 6800–3600 cal yrs BP), when the sea level reached itshighest 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 ofthe water table, conditions were favourable for the spread of mangrove, swamp and possibly riverine forest.During the late Holocene after ca. 3600 cal yrs BP a decrease of Podocarpus and other trees as well as anincrease of Chenopodiaceae/Amaranthaceae, grasses and Phoenix coincide with a return to lower sea levelsand drier conditions. The decrease of all trees including Phoenix at ca. 700 cal yrs BP, accompanied by rapidsedimentation rates, possibly reflect forest clearing and upland erosion induced by activities of Iron Agesettlers. A dry period at the globally recognized onset of the Little Ice Age might have contributed to thesechanges. Late Iron Age settlers have probably already introduced Zea mays, which was detected in the profilesince ca. 210 BP. The appearance of neophytes like Pinus, Casuarina and pollen of Ambrosia-type in theyoungest sediments indicates increased disturbance of European settlements and land use since ca.100 cal yrs BP.

University of the Free State, P.O.

ann).

l rights reserved.

© 2010 Elsevier B.V. All rights reserved.

1. Introduction

In South Africa, degradation and loss of wetlands together withtheir biodiversity and sources of proxy evidence of past changes havebeen extensive over the last century. Increased agricultural activities,urban development and climate change poses further threats forenvironments in areas like KwaZulu-Natal (Kotze et al., 1995; Kotzeand O'Connor, 2000). The Mfolozi catchment, in which several lakesincluding Lake Eteza occur, is the focus of this paper. It had lost about58% of its former wetlands by 1989. Erosion of the top soil in the area

increased alarmingly during the recent times (Begg, 1989; Scott andSteenkamp, 1996). To provide urgently needed knowledge of thestructure and functioning of local wetlands and the changes of theregional vegetation due to climatic fluctuations in the past (Kotze andO'Connor, 2000), and to place it in context of regional and globalenvironmental change, we report here on a detailed palynologicalanalysis of a 2072 cm pollen core that was taken in 1992 from LakeEteza (or Lake Teza, Fig. 1). The core was the subject of a provisionalreport on anthropogenic disturbance and increased silting-up of thecoastal area (Scott and Steenkamp, 1996), but here we investigate itsdating, pollen content and interpretation of Holocene environmentalconditions in detail.

Continuous pollen records are generally scarce in Southern Africadue to a lack of lake and peat deposits (Scott and Lee-Thorp, 2004).

http://dx.doi.org/10.1016/j.revpalbo.2010.05.001

mailto:[email protected]

Unlabelled image

http://dx.doi.org/10.1016/j.revpalbo.2010.05.001

Unlabelled image

http://www.sciencedirect.com/science/journal/00346667

Fig. 1. Locality map; upper diagram: map of South Africa with boundaries of summer and winter rainfall areas, indication of study site (northern coastal KwaZulu-Natal), lowerdiagram: map of the northern KwaZulu-Natal coastal plain with localities discussed in text and vegetation units (after Mucina and Rutherford, 2006). IOCB = Indian Ocean CoastalBelt.

40 F.H. Neumann et al. / Review of Palaeobotany and Palynology 162 (2010) 39–53

However, the Maputaland coastal plain in KwaZulu-Natal, containspolliniferous deposits inwetlands and lakes, which have great potentialfor palynological studies (Grundling et al., 1998). Pollen from severalsequences in KwaZulu-Natalwas studied byMazus (2000), but this wasrestricted to Podocarpus, which showed that this genus was moreimportant in the province during the Middle Holocene. A Holocene

pollen record from theMdlanzi swamps spanning about 1500 yrs, basedon only a single AMS radiocarbon date, provides a parallel sequence forthe late Holocene (Turner and Plater, 2004, Fig. 1). Neumann et al.(2008) present the vegetation history of the last 1500 yrs at coastal LakeSibaya in much higher dating and sample resolution and also report ona short interval from the middle Holocene. A core from the Mfabeni

image of Fig.�1

41F.H. Neumann et al. / Review of Palaeobotany and Palynology 162 (2010) 39–53

peatlands close to Lake St. Lucia gives a N45000 yrs long palynologicalrecord but the pollen types are only identified to family level and itsHolocene chronology is unresolvedwith only one available radiocarbondate (Mazus, 2000; Finch, 2005; Roberts et al., 2006; Finch and Hill,2008, Fig. 1). From the coastal lowland of southern Mozambique twowell-dated pollen diagrams are available providing evidence of humanactivities and regional climate changes over the last 1600 years(Ekblom, 2004, 2008). Further to the west, a pollen study from theBraamhoek wetland on the escarpment in the eastern Free State nearthe Kwazulu-Natal boundary, gives information about vegetationchanges during the last 16000 yrs, but resolution is rather low for theHolocene section of the profilewith highAsteraceae and low Podocarpuspollen percentages suggesting a decline in moisture during the middleHolocene (Norström et al., 2009). Diatom and phytolith evidence fromthe Braamhoek wetland supports in general the conclusions of theBraamhoek pollen record (Finné et al., 2010).

While considerable potential for Quaternary pollen studies in lakes,swamps and peat lands in eastern South Africa, e.g. in the Kosi system,exists (Grundling et al., 1998; Wright et al., 1999; Mazus, 2000; Miller,2001), the history of this region as part of processes that define climaticchanges in Southern Africa and the Southern Hemisphere, is still poorlyunderstood. In view of recent questions about the significance ofSouthern Hemisphere precessional forcing in Holocene developmentsof Southern Africa climates (Chase et al., 2009, 2010), the Eteza recordprovides important insights to resolve this matter. Other palaeoecolo-gical information from the Holocene of the region can be used forcomparisonwith pollen records. For example Bard et al. (1997) present,in the frame of a paper on the inter-hemispheric synchrony of the lastdeglaciation, an alkenone record from the Mozambique Channel (coreMD79257, 20°24′S, 36°20′E) which is used to reconstruct averagepalaeotemperatures for the last 150 ka. Sea Surface Temperatures (SST,Fig. 3) rise from about 26.2 °C at ca. 10000 cal yrs BP to ca. 27.6 °C at ca.7000 cal yrs BP. Relatively high SST prevail until ca. cal yrs 4100 BP, thenSST drops to b27 °C at ca. 1200 cal yrs BP (Bard et al., 1997; Mayewskiet al., 2004). Additionally a very detailed precipitation record forKwaZulu-Natal since 650 cal yrs BP is available from tree-ring widthmeasurements from a Podocarpus tree from the Natal midlands, whichshows a dry Little Ice Age at ca. 650–450 cal yrs BP andhumid periods atca. 350 and ca.150 cal yrs BP, respectively (Vogel et al., 2001).

In combination with these records for the Holocene of coastalKwazulu-Natal, the continuous deposits of Lake Eteza on theMsunduzeRiver with its detailed pollen sequence and robust chronological sup-port, show great potential for elucidating the coastal vegetation andclimate during the last 10200 yrs (Fig. 1).We compare and correlate ourwell-dated record, which encompasses 10200 yrs of continuoussedimentation and vegetation change, with sea level changes and theSST fluctuations of the region (Jaritz et al., 1977; Bard et al., 1997;Ramsay and Cooper, 2002; Neumann et al., 2008). This contributes to abetter understanding of Holocene atmospheric changes in coastalKwaZulu-Natal, presumably triggered by fluctuations of SST in theMozambique Channel, and the response of vegetation in easternsouthern Africa. The detailed picture of vegetation and landscapeschanges (including anthropogenic pollen indicators) since the arrival ofEuropean settlers is analyzed and evaluated.

Goals of this study are:

1. To gain a better understanding of the climate driven vegetationchanges in coastal KwaZulu-Natal during the Holocene, which willprovide a greater understanding of Southern African and globalclimatic variability.

2. To focus on prominent pollen fluctuations which are probablyrelated to human impact since the appearance of the first Iron Agesettlers between 350 AD and 650 AD (1650–1350 cal yrs BP; Vogel,1995; Bousman, 1998; Huffman, 2007). Therefore a detailed pictureof vegetation and landscapes changes (including anthropogenicpollen indicators) since the arrival of European settlers is presented.

3. To further analyse the history of Podocarpus and mangrove/swampforests (Mazus, 2000), which seem to be of high relevance foreastern South Africa, in the light of climate variability and humandisturbances.

Our investigations also include an analysis of the sediment, mollusc,andmicroscopic charcoal content of the profile which provide evidenceof veld fires.

2. Regional setting

2.1. Geomorphology, hydrology and geology

Lake Eteza (latitude 28.5167°S, longitude 32.15°E, 14 m a.m.s.l.) isone of several small lakes, which are located on the southwesternperiphery of the Mfolozi River floodplain (Grenfell et al., 2009, Fig. 1).It is approximately 25 km away from the east coast with its duneridges and is situated on the Msunduze River, a tributary to theMfolozi River (Fig. 1). The Msunduze River is 70 km long and has asmall catchment of 559 km2 (Lindsay et al., 1996). The freshwater lakeof ca. 2.4 km2 has a maximal water depth of 210 cm (Howard-Williams, 1980). The Msunduze River flows into the Mfolozi Riverfloodplain and is impounded as Lake Eteza by an alluvial fan (Scottand Steenkamp, 1996; Grenfell et al., 2009). The outflow forms ayazoo stream that joins the Mfolozi at its mouth 25 km away justsouth of the St. Lucia Estuary (Grenfell et al., 2009). When the Mfolozioverflows, water can push back up the Msunduze River into LakeEteza.

The water colour in the lake is stained brown (conductivity:800 µs cm−1), and the substrate is dark brown silt (Howard-Williams,1980). The Mfolozi system is affected by highly seasonal and veryvariable precipitation. Therefore clastic sediments dominate theMfoloziRiver floodplain (Grenfell et al., 2009). The catchment of the upperMsunduze River drains Mesozoic basalt, while the Mfolozi floodplain isdominated by alluvium (Roberts et al., 2006) that accounted for ca.30 cm of pale silt that spilled over in Lake Eteza during the DomoinaCyclone of 1984 (Scott and Steenkamp, 1996). The members of theMaputaland Group, deposited from the Miocene until the Holocene,comprise numerous fossiliferous beds, palaeodune deposits, and peats,e.g. the Middle Pleistocene Port Dunford Formation with mammalianfossils and Pleistocene pollen (Scott et al., 1992; Oschadleus et al., 1996;Maud, 2000). As sea level dropped during the last glacial, reaching aminimum of−120 m belowmodern sea level at ca.18000 yr BP, a newerosional phase began, which carved deep coastal valleys. As sea levelrose and coastal dunes formed during the Early and Middle Holocenesaline lagoons developed into freshwater lakes (Sibayi Formation,Wright et al., 2000). The heavy impacts on the environment and over-grazing must have accelerated the runoff, causing back-flooding andinfluencing thewater balance, so that the lake dried up during 1992 and1994 as result of extremely low precipitation (Scott and Steenkamp,1996).

2.2. Climate, vegetation, archaeology and history of land use

KwaZulu-Natal has a humid, subtropical climate due to onshoreeasterly atmospheric flow and the warm Agulhas current that con-tributes to convective rainfall, high soil moisture and a densevegetation cover (DeJager and Schulze, 1977; Schulze, 1982; Walker,1990; Jury et al., 1993; Jury, 1998). Mean annual rainfall in KwaZulu-Natal varies from 760 mm in the northern interior to 1250 mm alongthe coast and in themountains. Near the coast the precipitation occursmostly during February and March (Schulze, 1965). Main winddirections in KwaZulu-Natal are from the northeast and southwest.SST (Sea Surface Temperature) in the southwest Indian Ocean is ofmajor importance for the rainfall in northeastern KwaZulu-Natal. Inwet years between 1975 and 1984 a strong dipole existed between


SST differences in the southern Mozambique Channel offshoreKwaZulu-Natal (+0.86 °C) and the central Indian Ocean (−0.82 °C)(Jury and Pathack, 1993; Jury et al., 1994; Jury et al., 2002). Increasesin KwaZulu-Natal precipitation correspond to higher warm waterflows south into the offshore Agulhas current because of changes inthe wind stress field (Jury and Pathack, 1993; Lutjeharms et al., 2001).Also the weak beginning of Indian monsoon outflow, triggered by lowSST in the Central Indian Ocean, and reduced penetration across theequator is linked to high precipitation over southern Africa (Jury andPathack, 1993). These patterns suggest that stronger atmosphericcirculation on the southwestern Indian Ocean and the increase of SSTin the southern Mozambique Channel positively influences precipi-tation in KwaZulu-Natal.

Lake Eteza is in a in small nature reserve,managed by the KwaZulu-Natal Nature Conservation Service (KZNNCS), surrounded by exoticvegetation such as Eucalyptus and Pinus plantations and sugar canefields (Scott and Steenkamp, 1996). Degraded Acaciawoodland occursin over-grazed areas to thewest in the upstream catchment area of theMfolozi system (Scott and Steenkamp, 1996). The natural vegetationin northeastern KwaZulu-Natal is classified as Savanna, Forest andIndian Coastal Belt Biomes and is dominated by forest, swamp,wetland and grassland communities (Fig. 1, Eeley et al., 1999; Mucinaand Rutherford, 2006). Lake Eteza lies in the Maputaland Coastal Belt,which is up to 35 km wide and part of the Indian Ocean Coastal BeltBiome (Mucina et al., 2006). Important trees and shrubs on often poorand leached soils include Syzigium cordatum, Acacia natalitia, Apodytesdimidiata, Euclea natalensis, Rhus natalensis, Phoenix reclinata, andHyphaene coriacea (all plant names are according to Germishuizen andMeyer, 2003).

To the northeast and southeast Maputaland Wooded Grassland isfound with trees like Hyphaene coriacea and Diospyros lycioides, grassesand rich herbaceousflora (Mucina et al., 2006). Immediately to thewestof Mtubatuba and Lake Eteza at an altitude between 40 and 300 m,Zululand Coastal Thornveldwithblack soils andhigh clay content, formspart of the Savanna Biome (Rutherford et al., 2006, Fig. 1). Woodyspecies include Phoenix reclinata, Gymnosporia senegalensis and to alesser degree Acacia and Euphorbia species, Euclea schimperi, Spirosta-chys africana, Sclerocarya caffra, Dombeya rotundifolia and Acalyphapeduncularis (Walker, 1980; Mucina and Rutherford, 2006). NorthernCoastal Forest grows on predominantly well-developed sandy-loamysoils to the northeast near St. Lucia and to the east near the Mfoloziswamps on plains and along the coast on dunes (Mucina andGeldenhuys, 2006). Prominent trees include Mimusops caffra, Engler-ophytum natalense, Rhus nebulosa, Manilkara concolor, and Eucleanatalensis. Isoglossa woodii is widespread in the undergrowth.

Swamp forest can be found in small pockets north of Richards Bayon very fine, waterlogged soil with anoxic conditions and near Lake St.Lucia on sand or sandy loam (Mucina and Geldenhuys, 2006, Fig. 1).Common trees are Barringtonia racemosa, Macaranga capensis,Syzigium cordatum, Rauvolfia caffra, and Phoenix reclinata. Podocarpusfalcatus is rare near Lake Eteza but is reported from the northern Mosiswamp north of Lake Sibaya. Mangrove forest (Mucina and Gelden-huys, 2006) can be found in the Mfolozi floodplain to the east of LakeEteza at the St. Lucia estuary on saline and anoxic soils (Fig. 1).Bruguieria gymnorrhiza and Avicennia marina are recorded from theMfolozi estuarine system and Lake St. Lucia, whereas Rhizophoramucronata grows near Richards Bay (Allanson and Baird, 1999). Allmangrove trees are pollinated by insects, birds or bats and producerather low amount of pollen (Berjak et al., 1997) and when found inpollen assemblages probably indicate relative closeness of these trees.

Subtropical dune thicket (Mucina et al., 2006) exists along the coastclose to the St. Lucia estuary. It comprises a high diversity of oftenstunted trees and shrubs like species of Mimusops, Apodytes, Phoenix,Canthium, Euclea, Dodonaea, Passerina, Isoglossa and many others.

Near St. Lucia and Richards Bay subtropical freshwater wetlands(Mucina et al., 2006) are common. Small trees are Phoenix reclinata

and Hyphaene coriacea. Grasses are abundant and aquatics includeNymphaea nouchali, Aponogeton desertorum, Potamogeton crispus andmany others. Reeds and sedges include Typha capensis, Cyperuspapyrus and Phragmites australis. On the seashore close to the estuaryalong the dune ridges a small patch of subtropical seashore vegetationoccur (Mucina et al., 2006).

The humid eastern coast of South Africa attracted early Bantufarmers and pastoralists (Bruton et al. 1980). Huffman (2007)describes KwaZulu-Natal as an optimal region for mixed farming dueto permanent rivers, and an even distribution of woodland, grasslandand arable land. Evidence exists for Early Iron Age pastoralists since ca.1650 cal yrs BP at Enkwazini near Lake St. Lucia and close to Lake Eteza(Bousman, 1998). The Iron Age in southern and eastern Africa extendsover the last ca. 2000 years and distinguishes people, who were Bantuspeaking metal using agriculturalists, from Later Stone Age Khoisanpastoralists (Huffman, 1982). Huffman (2007) differentiates inSouthern Africa between the Early Iron Age (1750–1050 BP), theMiddle Iron Age (1050–650 BP) and the Late Iron Age (650–110 BP).Early Iron Age farmers, cultivating sorghum and millet, practicedshifting cultivation in the coastal dunes of KwaZulu-Natal ca.950 cal yr BP (ca. 1000 AD) (Hall, 1980;MacDevette, 1989; Grundling,pers. comm.). According to the pottery evidence, Nguni farmersmovedinto the coastal region ca. 900 BP. In historic times, these peoplefocused more on herding than other South African Bantu speakers(pers. comm. G. Whitelaw 2010, Natal Museum reports). During the15th century Late Iron Age Bantu arrived in KwaZulu-Natal (Brutonet al., 1980). Those pre-European settlers might have been engaged inforest clearings to secure space for settlements and pastures andgathered timber as fuel for cooking, house construction, domesticheating and iron smelting (Bruton et al., 1980; Neumann et al., 2008).Forests might have been partially replaced by secondary grasslandmaintained by fire which also increased the number of grazingherbivores, e.g. antelopes (Hall, 1980). West et al. (2000) formed thehypothesis that this long history of utilization induced a patchy forestof shade-intolerant species. Although maize was introduced to theCape region in South Africa and the Maputo region in Mozambiqueduring the 17th century, it only reached KwaZulu-Natal at the end ofthe 18th century where it was soon cultivated by the Late Iron Agepopulation (McCann, 2005;Huffman2006, 2007). However,Whitelaw(pers. comm. 2007, in Neumann et al., 2008) suggests the introductionof maize to KwaZulu-Natal in the 17th century. After the foundation ofthe Boer Republic of Natalia in 1839, Pinus was seemingly present inthe Region (Williams, 1921; Neumann et al., 2008). Far distanttransport of airborne pine pollen from the Cape region, where Pinuswas planted since the 17th century, cannot be excluded (Shaughnessy,1986). Plantations of exotic trees (pines and eucalypts) and sugar canehave replaced parts of the coastal forest in KwaZulu-Natal since about1928–1929 and further expansions took place in the 1940's and 1970's(Marwick, 1973).

3. Materials and methods

Coring of the lake was made possible when the lake floor becameexposed during the 1992 drought (Scott and Steenkamp, 1996). Thecore was extracted by means of a motorized coring rig fitted with ca.5 cm metal tubes. The material for the present study is derived fromthis core, sub-sampled between 1992 and 1997, after which theremainder of the core was given to the Council for Geosciences inKwazulu-Natal for storage and further study. Unfortunately it wassubsequently lost through burglary and vandalism (G.A. Botha, pers.comm.). The degree of recovery was high, and there was a smalldegree of compaction but exact information was lost with the markedcore boxes.

Pollen was extracted after digestion in KOH and mineral sep-arationwith a heavy liquid (ZnCl2 with a specific gravity of 2). In a fewof the samples additional acetolysis was preformed to improve pollen


concentration. Pollen analysis was accomplished with fixed mount-ings (glycerine jelly) using oil immersion microscopy. The slides werestudied under a Zeiss Axiophot petrographic microscope and photo-graphs taken with a digital camera at 400 and 1000 times mag-nification. Measurements of pollen grains (e.g. Poaceae) as well asphotographs were undertaken using the image analysis programAnalySIS 5.1. Large pollen grains of Poaceae of between 60 and 80 µmdiameter represent Zea mays (Scott, 1982; Faegri and Iversen, 1993).Only charcoal fragments of N120 µm were counted and included inthe pollen diagram. The zonation of the pollen diagram is based onvisual observations of changes in palynomorph assemblages and therelative abundance of individual species. Percentages of a selection ofprominent pollen types with potential indicator values for environ-mental conditions, based on the sum of their total, were subjected toprincipal components analysis (PCA), using XLSTAT version 7 (http://www.xlstat.com/). PCA scores of the first two factors are intended as adescriptive tool to summarize the main trends through the profile.

4. Results

4.1. Lithology

Lithological units of the Eteza core are described in Fig. 2a. The baseof the profile (2072–1929 cm, Units A–B) is sandy. Although the totallength of the core is 2300 cm, the section 2300 to 2072 cm, was notsampled for pollen analysis. However, the bottom part of the core(2200–2072 cm) is hard brown sand apparently belonging to the UpperCretaceous that underlies the area (R.R. Maud, pers. comm.). There is asampling gap between 1901 and 1929 cm. Between 1901 and 452 cmdark brown to black clays consisted partially of carbonate concretions,or perhaps post-diagenetic gypsum, mollusc shells, pyrite and Fe/Mnconcretions (Units C–I). A 10 cm thick sand lens at a depth of 1567 cm isnoted in Unit E. Sediments between 40 and 452 cm consist of dark tomedium brown, organic rich clays in which Fe/Mn concretions areabundant (Units J–L). The uppermost 3 cm of the sequence consist ofblack lake clays, covering 30 cm thick, light brown silt that wasinterpreted as sediments from the Domoina flood in January 1984(Scott and Steenkamp, 1996;UnitsM–N). A core at the boundary of LakeEteza, described by Grenfell et al. (2009), features a 40 cm thick layer ofmedium-grained silt, which is probably the equivalent of Unit M.

4.2. Molluscs and diatoms

Finely dispersed mollusc shell fragments but only few completemolluscs are observed from a depth of ca. 6 m downward (Fig. 2a;Table 1). Preliminary observations of mollusc remains of the Etezaprofile suggest that at least part of the sequence is of fresh water ormangrove origin. At a deeper level (ca. 1950 cm), the tentative spec-imen of Nassarius kraussianus in Unit A could indicate marineconditions but it is unlikely that it represents an intertidal environ-ment because sea levels were low at the time ca. 10000 cal yrs BP (seediscussion of sea levels below) (Branch et al., 2007). The identifiedspecimens between ca. 980 cm and 680 cm, suggest a freshwaterhabitat or mangroves rather than marine conditions as was assumedpreviously by Scott and Steenkamp (1996).

Prof C. Stager, Paul Smiths College (New York), analyzed 20 samplesfor diatoms but found none. Diatomsmight have been destroyed due todrying or alkaline conditions (Barron, 1993). Marine indicators, e.g.microforaminiferal linings and dinoflagellates, were not observed.

4.3. Dating and sedimentation rate

Twenty radiocarbondatesweremeasured at depths between224 and1860 cm. Fifteen bulk sediment samples were assayed on organicsediments and one on charcoal at the Council for Scientific and IndustrialResearch inPretoria and4AMSsamplesonorganic sediment (3)and shell

(1)weremeasuredat theRadiocarbonLaboratory inGroningen (Table 2).All but one sample (Pta-9787) were corrected for carbon isotopicfractionation effects. It was run on wood charcoal and no correctionwas provided by the laboratory in this case. All sampleswere adjusted fortree-ring calibration with corrections for the Southern Hemisphere usingthe OxCal Program v 4.0.5. The two uppermost assays (Pta-6231, 224 cmdepth and Pta-6239, 324 cm) were eliminated from further analysis asthey were clearly too old considering their stratigraphic positions. Thesingle assay on shell (GrA-41303, 1760 cm depth) was also eliminated asit was too young in comparison to adjacent assays. GrA-42427 and Pta-9787 were combined into a single age estimate as they were from thesame depth (402 cm), and Pta-6242 and Pta-6293 were treated in asimilar manner (483 cm depth). The remaining age estimates werestratigraphically constrained for vertical placement using the OxCal v4.0.5 Program. The results of these calculations are presented in Table 2and plotted in Fig. 2c. Using the stratigraphically constrained ageestimations in Table 2, calibrated age estimation for individual sampleswere derived by calculating linear regressions for each pair of adjoiningassays. These age estimations are presented in Fig. 2b, which plotsindividual pollen samples and radiocarbon age estimates. A two standarddeviation (95.4%) confidence limit was calculated and plotted for eachradiocarbon sample age (Fig. 2b, c).

Two anomalously old dates (depths 224 cm and 324 cm) in thestudied core can be interpreted as derived from increased erosion dueto anthropogenic disturbance upstream (Scott and Steenkamp, 1996).These samples were not considered in the age model for the pollensamples but the rest of the samples give a fairly consistent chronologyfor the sequencewith exceptions at the 930 cm, 1332 cm and 1760 cmlevels, where samples seem to be younger than the general trend(Table 2). However, the stratigraphically constrained age calibrationsfor the upper two samples (depths: 930 cm, 1332 cm) account for thisreversal and recalibrates the ages based on their stratigraphicplacement (Table 2, Fig. 2c). The latter anomalous determination in adepth of 1760 cm (ca. 600 yrs younger than the sediment date), wasbased on shell, andwas therefore excluded in the generation of our agemodel because of uncertainties associatedwith dating of this material,which may include burrowing of molluscs. A hard-water reservoireffect, as estimated between 50 and 550 yrs too old for Lake Sibaya(Neumann et al., 2008), may also have affected dates at Lake Eteza,making them a little too old, but this was not addressed formally in thesample age model. Further, reworking of organics from upstreamQuaternary alluvium, although not as obvious as in the upper twodates, may also have affected lower parts of the core. Furtheruncertainty in the dating of the core may exists such as possibility ofbioturbation by animals such as hippopotami, which have beenreported in the first descriptions of the lake in 1841 (Delegorgue,1990), but in general the chronology seems to be consistent.

Based on calibrated ages and historic observations dramaticvariations in deposition rates occur in the Eteza sediment record(Fig. 2d). The highest sedimentation rate, 4.13 cm/yr, is for the periodbetween the sample collection date of 1992 (−43 BP) and 1984(−35 BP). These sediments include those deposited by the Domoinaflood in January 1984 and later events. Most of these sediments areprobably a result of this singular flood event. Elevated sedimen-tation rates (average=1.06 cm/yr) were also recorded between−35calyrs BP (AD 1984) and 394 cal yrs BP (33–402 cm), between4066 and 4146 cal yrs BP (830–930 cm) and between 6506 and6602 cal yrs BP (1228–1332 cm). Moderately high rates (avera-ge=0.32 cm/yr) were recorded for the bottom four samples between7768 and 9196 cal yrs BP (1430–1860 cm). The remaining sedimen-tation rates average only 0.13 cm/yr.

4.4. Palynology and PCA

The pollen concentrations throughout the core were reasonableexcept in the bottom part of the profile (1880–2072 cm) where the

http://www.xlstat.com/

http://www.xlstat.com/

Fig. 2. Age determinations at Lake Eteza; a: lithology of core, description of lithological units and b: Lake Eteza individual pollen sample age estimations and radiocarbon sample stratigraphically constrained age calibrations with 95.4% errorbars plotted by depth; c: plot of radiocarbon samples showing age frequency distributions for calibrated and stratigraphically constrained calibrated radiocarbon age estimates using OxCal. Un-modelled calibrated age frequency distributionsshown in light gray and stratigraphically constrained calibrated age frequency distributions shown in black; and d (inset): estimated deposition rates (cm/yr) for Lake Eteza sediments.

44F.H

.Neum

annet

al./Review

ofPalaeobotany

andPalynology

162(2010)

39–53

image of Fig.�2

Table 1Mollusc contents of the Eteza core.

Unit Depth Molluscs Environment

I 680–682 cm Well preserved CorbiculidsBivalve fragments

N/A

H 748–750 cm Rich mother of pearlfragmentsNo identifiable gastropodsPatellid-like forms

N/A

G 968–966 cm Well preserved CorbiculidsBulinid gastropodMelanoid type of gastropod.

Probably freshwater

G 979–977 cm Bulinus tropicus(Brown et al. 1996)

Fresh water; shallow slowrunning water, on soft mudand/or sand and salinityrange between freshwater,estuarine and mangrovehabitats (Abbot, 1973;Roessler et al., 1977; Neck,1985; Beesley et al., 1998).

Melanoides turberculataCorbiculids

A ∼1950 cm Nassarius kraussianus(Scott and Steenkamp, 1996)

Wide range of environmentsfrom freshwater to marine


total land pollen sumwas often below 250 evenwhen all the availablematerial of our samples of ca. 5 g, was analyzed (Fig. 3). The Etezapollen sequence is subdivided in zones (1–4) on the basis of pollenand spore composition and relative abundance of certain species(Table 3). The time resolution per pollen sample is ca. 20 yrs above adepth of 357 cm (ca. 375 cal yrs BP) and 225 yrs in average for thesection of the Eteza record between 375 and 2072 cm depth.

ThePCA results showed interesting trends especiallywhenexcludingthe independently fluctuating Poaceae. The first component (F1, 17%variance, Fig. 4) showedhighpositive loadings on Podocarpus,Manilkara,Rhus, Dicliptera, Isoglossa and Mimusops and high negative loadings onCyperaceae, Asteraceae and Chenopodiaceae, indicating a contrast

Table 2Radiocarbon ages, calibrated ages and stratigraphically constrained calibrated ages for samplconstrained calibrations use the Bayesian procedures in the OxCal Program (Bronk Ramsey 2

Explanation: * = eliminated samples, os = organic sediments, bs = bulk sediment, GrA-nucombined samples shaded in gray.

between moist coastal forest elements and open herbal vegetation. Inthe second component (F2, 11%) Phoenix, Olea, Chenopodiaceae, Crotonand Celtis (strongly positive) and Polygonum, Rauvolfia, Podocarpus,Dicliptera and Anthospermum (strongly negative) contrasts openwoodland indicators against moisture demanding plants.

5. Discussion

5.1. Vegetation history

In the interpretation of the vegetation history we did not in-vestigatemodern surface pollen data because the local environment isheavily disturbed by forestry and agricultural industries. For compar-ison with modern spectra we therefore consider the upper pollensamples in the sequence from before the increase in pine pollen belowa depth of 65 cm as the closest to modern potential natural vegetationalthough these could be slightly influenced by the Iron Age herderactivity or past climatic variations.

The pollen diagram of Lake Eteza is dominated by Poaceae (22–90%) suggesting a strong influence of grassy woodland savanna.Elements of the Savanna Biome and Maputaland Coastal Belt Biomeare abundant while mangrove and swamp forests types are alsorecorded. Podocarpus pollen, which dominates the arboreal spectra inthe middle part of the Lake Eteza profile, grows in the coastal andswamp forest but is more abundant in Afromontane and Mistbeltforest (Pooley, 1993; Coates-Palgraves, 2002). Phoenix, which oftenappears in the sequence, can be found along rivers, in forest andgrassland (Pooley, 1993). Fynbos elements, e.g. Ericaceae, Protea,Passerina and Restionaceae, are rare, some of which probably are dueto long-distance transport from the escarpment. Of these the Passerinapollen is mostly from the coastal species, e.g. Passerina rigida (Pooley,1993), while Restio zuluensis represents a generic element of theMaputaland coastal belt and Proteaceae pollen probably representsProtea roupellia and P. caffra from distant grassy hills and mountain

es collected from Lake Eteza. Calibrations use OxCal Program v4.1. The stratigraphically008, 2009).

mbers represent AMS dates and Pta-numbers charcoal or bulk sediment dates, data for

Unlabelled image

Fig. 3. Simplified pollen diagram of the Lake Eteza borehole based on modelled ages, charcoal values, total land pollen, pollen zones and PCA (F1 and F2). Upper diagram: trees and shrubs, lower diagram: herbs, aquatics and swamp plants,cryptograms and algae. Upper right: Sea Surface Temperature (SST) fluctuations in °C as reported by Bard et al. (1997) for core MD79257 in the Mozambique Channel.

46F.H

.Neum

annet

al./Review

ofPalaeobotany

andPalynology

162(2010)

39–53

image of Fig.�3

Table 3Pollen assemblage and abundance zones from the Lake Eteza profile with assigneddepths and time periods, right: interpretation of pollen fluctuation linked to climatechange.

Zone Pollencharacteristics

Depth(cm)

Age cal yrs BP Climaticinterpretation

1 NeophytesPoaceaeProteaCliffortia

465–20 ca. 700–−42 Climate changebhuman impactOnset of Little Ice Ageca. 700 cal yrs BP

2 PhoenixPoaceaeAsteraceae

758–465 ca. 3600–700 Drier than Zone 3Continued gradualdecrease of SSTSea levels dropMangrove, swampforest decline

3 Podocarpus,IsoglossaOther treesMangrovesAquaticsFerns

1350–758 Ca. 6800–3600 High precipitationHigh SSTRelatively high sealevel

4 Issoglossa declinesPhoenix declinesOlea declinesPoaceae increasesAcacia gerardii

2065.5–1350 Ca. 10 200–6800 Relatively wet ca.10 000 cal yrs BPBecoming dry ca.8000–7000 cal yrs BPIncrease SST/sea level


slopes in KwaZulu-Natal (Pooley, 1993; Coates-Palgraves, 2002;Mucina et al., 2006). Pollen from other trees like Olea, Celtis or Crotonthat grow in a variety of habitats is also present in the sequencewhile that of water and swamp plants, e.g., Cyperaceae, Typha andNymphaea is abundant in the upper half of the profile.

Fig. 4. PCA loadings of the first two factors of sele

5.1.1. Zone 4 (2065.5–1350 cm): ca. 10200–6800 cal yrs BPMost trees, includingPodocarpus,Dombeya,Manilkara and Canthium,

are present in low percentages indicating woody vegetation of theIndian Ocean Coastal Belt biomes in the region ca. 10200 cal yrs BP. Theglobally recognized Holocene Thermal Maximum, generally character-ized by higher temperatures and often wetter conditions, e.g. in Africaand the Caribic, started ca. 10500 cal yrs BP following the Last GlacialMaximum (De Menocal et al., 2000; Haug et al., 2001). Up to a depth of1930 cm (ca. 9500 cal yrs BP), the profile is sandy and the depositionrate is relatively high which might indicate a fluviatile regime (Fig. 2d).Phoenix reaches high percentages around 9000 cal yrs BP suggestingPalm Veld, a seasonally wet grassland with abundant Phoenix stands(Mucina et al., 2006), although pockets of forest with e.g.Olea, Rhus andManilkara existed suggesting sub-humid conditions. Isoglossa, anundergrowth element, is common in the lower half of the zone butdecreases after ca. 8500 cal yrs BP, Croton and Olea are probablyreflecting relatively open forest. Croton and Acacia gerardii mightindicate wooded grassland (see Coates-Palgraves, 2002; Ross, 1971).Poaceae increases gradually towards ca. 8000 cal yrs BP but decrease atthe transition to Zone 3 ca. 6800 cal yrs BP. In view of general ar-chaeological indications of earliest cultivation of cereals (Huffman,2007, see 2.2) we exclude that Poaceae pollen N50 µm in this zonerepresents cultivated grass. Poaceae pollen grains b26 µm, probablyproduced by Phragmites (Bonnefille and Riollet, 1980; Faegri, 1993), aremore abundant until ca. 9500 cal yrs BP and might indicate a reed belt.Although freshwater conditions allowing the growth of water, riverineforest, andmangrove forest and swamp plants seem rare in comparisonto Zones 1 to 3, various fern spores as well as higher tree percentagesmight indicate slightly moister conditions or a higher water table untilca. 8500 cal yrs BP. Cheno/Ams (Chenopodiaceae and Amaranthaceae)might either point to rather dry environmental condition or to salinemicroenvironments such as salt pans or coastal salt marshes (Dyer,

cted pollen types from Lake Eteza borehole.

image of Fig.�4


1975; Pooley, 2005). Artemisia prefers open habitats (Dyer, 1975).Crassulaceae, possibly succulents, can indicate dry environments inbushveld or grassland (Pooley, 2005).

Together with Cheno/Ams and Crassulaceae and Asteraceae,Poaceae gradually increase at the expense of Phoenix and other trees,peaking between ca. 8000 and 7000 cal yrs BP and might indicate ashift from woodland to a probably drier grassy ecosystem. This isindicated by the decline in both PCA curves (Figs. 3, 4). Data from theMfabeni peatland (Finch andHill, 2008) also indicate grassy conditionsat this time.

The SST from theMozambiqueChannel showageneral increase untilca. 7000 cal yrs BP, which is explained as a continuation of deglaciationafter the Last Glacial Maximum (Bard et al., 1997; Mayewski et al.,2004). Increasing SST of the southwestern Indian Oceanmight lead to awestward spread of the Agulhas current warmwaters and bring higherprecipitation to coastal KwaZulu-Natal (Jury and Pathack, 1993; Juryet al., 2002). A short term decrease in SST from ca. 27 °C to ca. 26.5 °Cbetween ca. 9000 and 8000 cal yrs BP might have decreased precipita-tion in northeastern South Africa and contributed to the environmentalshift to a more arid grassy environment observed in the Eteza record(Bard et al., 1997, Fig. 3). At 7200 cal yrs BP sedimentation rate mightindicate a shift from fluvial to lacustrine conditions (Fig. 2d).

5.1.2. Zone 3 (1350–758 cm): ca. 6800–3600 cal yrs BPAt ca. 6500 cal yrs BP, Poaceae percentages decrease and tree

pollen increases. Podocarpus gradually rises to a maximum of N30% atca. 3700 cal yrs BP and Phoenix reaches a minimum after peaking atca. 5500 cal yr BP. Forest percentages are the highest in this zonecorresponding with Mfabeni peatlands (Finch and Hill, 2008), whileMimusops, Rhus, Dombeya, Englerophytum,Manilkara and Canthium aswell as Acanthaceae (e.g. Isoglossa and Dicliptera) are abundant. Thezone is characterised by the regular appearance of swamp- andriverine forest trees, e.g. Rauvolfia, Polygala, Macaranga, and Psoralea.Mangrove elements include Bruguieria, Barringtonia, and Avicennia.Anthospermum, characteristic of grasslands or forest margins (Pooley,2005), increases. Phoenix reaches a maximum ca. 5500 cal yrs BP andPoaceae shows a peak ca. 5400 cal yrs BP. Abundant Typha, Persicaria,Gentianaceae, Nymphaea, Pseudoschizaea and cryptogams especiallyfrom ca. 5000 cal yrs BP onwards indicate a shift to freshwater andswamp conditions. Freshwater mollusc species are present from ca.4700 cal yrs BP. Melanoides tuberculata might indicate mangrove orestuarine conditions although the species can also be dominant infreshwater (Table 1).

The strong increase of forest trees dominated by Podocarpus, pointsto moist subtropical conditions, corresponding to a postulated 5 to 10%precipitation increase in Maputaland (Partridge, 1997). Between ca.7000 cal yrs BP and ca. 4000 cal yrs BP the SST of the MozambiqueChannel are the highest of the Holocene alkenone record (Bard et al.,1997) (Fig. 3). Strengthened southward drift of the warm Agulhascurrent might have increased rainfall in coastal KwaZulu-Natal,probably ameliorating conditions for subtropical forests. However, theSST curve (Bard et al., 1997) is slightly lower at ca. 5900 cal yrs BP andtogether with the pollen indicators points to slightly drier environmen-tal conditions although aridity was certainly more pronounced duringthe early Holocene in the region (see Section 5.1.1). An extensive RapidClimate Change event (RCC) is globally noted between ca. 5000 and6000 cal yrs BP when an aridity trend starts in Tropical Africa(Mayewski et al., 2004). The two PCA curves suggest a wet and forestedenvironment with abundant coastal forest elements (Fig. 3). In contrastpollen data from the Braamhoek wetland in the Eastern Free Stategrassland biome indicate asteraceous grassland while pollen of theadjacent afromontane forest, especially Podocarpus, is relatively lowsuggesting relatively dry conditions locally and regionally between7500 and 2500 cal yrs BP (Norström et al., 2009).

The abundance of mangrove and swamp forest elements ca. 6500–3600 cal yrs BP in the Eteza record represents a period of a high sea

level and a high ground water table with the sea shore considerablynearer to the study site (see discussion in Section 5.4). Charcoalpercentages show several high peaks during Zone 3, the highest at adepth of 11.5 m at ca. 6000 cal yrs BP, which probably indicate oc-casional fires in the wider region. Two single peaks of high sedi-mentation rate at ca. 6500 and ca. 4000 cal yrs BP might mark shortevents of increased sedimentation transport (Fig. 2d) for which thecause is uncertain. Remarkably both events lie close to peaks in SST asreconstructed for the core in the Mozambique Channel (Bard et al.,1997; Fig. 3). It is possible that tropical cyclones and floods over theMozambique Channel comparable to the Domoina flood in 1984(Grenfell et al., 2009) have transported high amounts of sedimentdown the rivers in KwaZulu-Natal (compare Jury et al., 1994).

5.1.3. Zone 2 (465–758 cm): ca. 3600–700 cal yrs BPAt ca. 3600 cal yrs BP, Podocarpus, percentages drop rapidly to about

8% ca. 3500 cal yrs BP. A similar retreat of Podocarpus forests is reportedby Mazus (2000) from ca. 3100 yrs BP, which is apparently a regionaltrend in coastal KwaZulu-Natal. The decrease of Podocarpus observed inthe Eteza record is accompanied by the retreat of other forest elements,namely Isoglossa,Mimusops,Manilkara, and Acacia and the beginning ofa return of more Phoenix pollen. Poaceae and Asteraceae percentagesgradually increase followed by the continuing rise of Phoenix pollen,peaking at a depth of 630 cmat ca. 2600 cal yrs BP. Consequently a shortperiod in the lower half of this zone (ca. 3500–2000 cal yrs BP),characterised by low tree/shrub percentages and high Poaceae andAsteraceae percentages, represents an apparently relatively dry grassyenvironment quite similar to those observed in the Lake Eteza pollenrecord before ca. 7000 cal yrs BP in Zone 4. Mayewski et al. (2004)describe an extensive global RCC between 3500 and 2500 cal yrs BPwhich caused pronounced aridity in Eastern Africa. Our data suggestthat this dry event affected also eastern South Africa. Unfortunately theperiod 3500–2500 cal yrs BP is not represented in the alkenone recordfrom coreMD79257 and a comparison to SST is not possible (Bard et al.,1997, Fig. 3). Conditions of initial low tree/shrub percentages and highPhoenix/Poaceae/Asteraceae percentages are characteristic for Zone 2,together with dramatic changes in the water plant and cryptogramcommunities. Typha, Pediastrum and fern spore percentages show aunique peak during the lower part of the zone, whereas Nymphaea andPseudoschizaea percentages are less pronounced than before. Thismightindicate that Typha and ferns were growing close to the coring location.

After ca. 2000 cal yrs BP, values of certain forest elements, includingSpirostachys, Isoglossa and Mimusops, and swamp-, riverine- andmangrove forest elements again began to increase. This trend is un-derlined by a shift to positive values in F1, indicatingmoremoist coastalforest elements, e.g. Sapotaceae and Isoglossa (Figs. 3, 4). Isoglossareaches the highest percentages within the pollen diagram ca.900 cal yrs BP. This increase is paralleled by the decrease of Poaceae,Asteraceae and Phoenix towards the top of the zone. It is possible thatIsoglossa benefitted from a more open canopy. Although these pollenindicators point to a partial return of forest elements after ca.2500 cal yrs BP, the Podocarpus curve steadily declines and highCheno/Am values might also be interpreted as a signal for dry or salinehabitats in the vicinity of Lake Eteza. The sharp increase of Spirostachysafricana ca. 800 cal yrs BP, points to savanna conditions. A strongpeakofCyperaceae and high percentages of various fern spores together withNymphaea and Persicaria indicate a mosaic of swampy and open waterhabitats during the same time period. In general the two PCA curvesindicate a shift from amoist forest habitat to open conditions (Figs. 3, 4).Lake levels were probably lower than during Zone 3 and account formore open swampy elements.

5.1.4. Zone 1 (465 cm–20 cm): ca. 700 cal yrs BP–1992 ADAt ca. 700 cal yrs BP a dramatic change occurred in the vegetation.

The values of tree and shrub pollen like Podocarpus, Spirostachys,Mimusops, Rauvolfia and other forest elements as well as Dicliptera,


Commelinaceae, charcoal values and allwater and swampplants showasharp decline. Phoenix pollen fluctuates below 10% in Zone 1. In contrastpercentages of Poaceae increase to about 85% in the lower half of Zone 1pushing the herb pollen percentages to amaximum of 90%. This changeis independently supported by the first factor in the PCA, reaching itslowest values in this zone and signalling open herbal vegetation (Fig. 3).Cheno/Ams, Asteraceae, Cliffortia and fynbos elements like Ericaceaeand Protea are prominent in Zone 1. Pollen probably indicate drier andless swampy conditions and the retreat of the forest elements. SouthernAfrica has a prominent cool and dry period ca. 600 BP (Mayewski et al.,2004). The decrease of trees ca. 700 cal yrs BP also marks the beginningof the cool/dry Little Ice agewhich lasted from650 to 150 cal yrs BP andcorresponds in time to the decline in solar irradiance during theMaunder and Sporer Minimum (Tyson and Preston-Whyte, 2004;Holmgren et al., 2003; Ekblom, 2008). Exceptionally low rainfall isevidenced by dendroclimatological data from the Natal midlandsbetween 650 and450 cal yrs BP (Vogel et al., 2001).

During this phase, anthropogenic influences overshadow climatechanges. The landscape around Lake Eteza was dominated by grass-land with forest patches. In contrast to Zone 4, which was alsodominated by Poaceae, Phoenix percentages stay low. The initialdecrease of date palms in Zone 1 together with the spreading of opengrassland might be attributed to Iron Age farming and herdingactivities since pastoralism and crop cultivation started ca. 1600 BP ineastern South Africa (Hall, 1980; Bousman, 1998; Huffman, 2007).Although settlement activities can be assumed, there are no visiblevegetation changes which can be explained by human impact beforeca. 700 cal yrs BP. However, resolution in the Eteza record is lowbetween 1700 and 700 cal yrs BP. Ekblom (2008) postulates that earlyagricultural communities might have had a low impact on vegetationin southern Mozambique based on the poor correlation betweencharcoal and vegetation shifts even though the area has had a farmingpopulation throughout the last ca. 1600 yrs. A similar explanation issuggested for the Eteza record. Anthropogenic activities included theuse of palms as sources of fibre, food (palm hearts, sap and fruits), oiland building material (Pooley, 1993, M. Bamford, pers. comm.) andforest clearing for grazing. The period beginning ca. 700 cal yrs BPmight coincide with an increase in human activity in the Lake Etezaregion. According to G.Whitelaw (pers. comm.) Nguni farmers movedinto coastal KwaZulu-Natal ca. 900 BP. Population numbers generallywere almost certainly higher after 900 BP as the site records fromnorth of Richards Bay suggest. Population pressure might have beengreater in the Eteza catchment after 700 BP. Peoplemight havemovedinto the coastal belt (including Eteza) with the onset of drier con-ditions (pers. comm., G. Whitelaw, 2010; Natal Museum Records).

Microscopic charcoal (Fig. 3) shows only minor peaks incomparison with the high peaks in the early Holocene suggestingthat Iron Age settlers controlled burning well but benefitted from analready open vegetation suitable for grazing, which at the same timeremoved available fuel for fires (Scott, 2002). The decrease of foresttype species in Lake Xiroche and Lake Nhaucati (southernMozambique) is temporally correlated with the repeated droughtsduring the Little Ice Age and can be dated to 535–450 cal yrs BP(Ekblom 2008). This is slightly later but roughly in the same timeframe than the forest decrease ca. 700 cal yrs BP in the Eteza record.Early settlersmight also have changed the hydrological conditions in away that most water- and swamp plants decreased or disappeared.However, low water tables due to a decrease in precipitation at thebeginning of the Little Ice Age might have been another cause. It ispossible that the groundwater table was lower than during periods ofa higher sea level (see Section 5.4, Ramsay 1995).

A combination of cool/dry conditions and human activity might bethe reason for the decline of trees and the spread of Poaceae. The lowarboreal values, the absence of fern spores, and decline of pollen fromwater- and swamp plants, most prominently Cyperaceae andNymphaea, might indicate less moist conditions.

The appearance of Poaceae N60 µm at a depth of 226 cm (ca.210 cal yrs BP) coincides with the cultivation of Zea mays at ca.300 cal yrs BP. In 211 cm depth (ca. 185 cal yrs BP) the first pine pollenoccurs and coincides with the spread of pine plantations in the CapeRegion. The strong increase of pinepollen in Zone1 beginning at a depthof 65 cmmight be due to large pine plantations in the coastal region ofKwaZulu-Natal since about 1928–1929 and in the St. Lucia region since1957 (Marwick, 1973; Thammet al., 1996) and corresponds reasonablywell with our age model. Casuarina and pollen of Ambrosia-type areprominent in the upper 65 cm of the profile coinciding with highdeposition rates especially above a depth of 96 cm (61 cal yrs BP)indicating stronger erosion with increased human disturbance, over-grazing and the establishment of plantations without undergrowth(Fig. 2d) (mentioned above).

5.2. Correlation and comparison to the palynological record of LakeSibaya (Neumann et al., 2008)

In order to obtain a more regional view, a correlation between theLakes Eteza sequence and the non-continuous Lake Sibaya record(Neumann et al., 2008) can be attempted. Due to a 5000 year gap inthe latter, this is only possible at ca. 7000 BP in the middle Holoceneand again at ca. 1400 cal yrs BP onwards. The later part of the LakeSibya record has a much higher resolution of radiocarbon dates andpollen levels than the Lake Eteza record. Accurate correlation due tothe available dating is not possible (Fig. 5). Evenwith inaccuracies likethe age error of 50–550 yrs that was estimated for the Lake Sibayarecord, attributed to a hard-water reservoir effect, the palynologicalanalyses at Lake Sibaya and Eteza strongly support each other.

The lower part of the Sibaya profile is characterised by high treepollen values, esp. Phoenix at ca. 7000 cal yrs BP corresponding withmiddle Holocene warm conditions at Eteza. In the later part a similardecline of tress and a sharp increase of Poaceae are observed in bothprofiles after ca. 1500 cal yrs BP. The vegetation development of thelast ca. 700 yrs is also generally similar in both diagrams, featuring aretreat of forests possibly as a result of Iron Age vegetation clearingfollowed by the more recent introduction of neophytes.

5.3. Modelling forest vegetation in the middle Holocene inKwazulu-Natal

In the light of an analysis of the history of Podocarpus andmangrove/swamp forests, the vegetation during the mid Holocene6800–3600 cal yrs BP deserves further consideration. Eeley et al.(1999) have modelled the distribution of forest biomes during wetter(precipitation: 7.5% higher than today) andmaybewarmer conditionsca. 7000 cal yrs BP. Apparently the model shows potential mixing ofelements of the Northern Afromontane Forest, the Southern Mist BeltForest and the Indian Ocean Coastal Belt along the Scarp Forest beltunder general conditions of forest expansion ca. 7000 cal yrs BP. Thismixing can be taken as an explanation for the species compositiondetected in the Lake Eteza pollen record. However, it seems that theforest was only fully developed by ca. 6800 cal yrs BP with highestPodocarpus percentages ca. 5000 cal yrs BP. Podocarpus, which is rarein coastal forest in KwaZulu-Natal under current conditions, but anelement of both Mistbelt and Afromontane Forests, was much morewidespread and was growing close to the site. Today scarp forestpatches can be found ca. 70 km north of Lake Eteza (Fig. 1) whereasNorthern Afrotemperate Forest occurs along the Great Escarpment ca.200 km and Mistbelt Forest ca. 100 km to the west. The highPodocarpus percentages 6800–3600 cal yrs BP support that those orcomparable forest types were very close to the site and, at least ca.5000 cal yrs BP, even dominant. Typical trees and forests elements ofthe coastal forest, e.g., Isoglossa, Apodytes or Mimusops, were alsoabundant, which speaks for a geographical closeness to the site.During the same time period a combination of high water table and

Fig. 5. Left: Regional comparison of the Lake Eteza and Lake Sibaya pollen sequences based on a depth scale (Neumann et al., 2008); middle: sea level data, radiocarbon dates for sea level indicators (Ramsay, 1995; Ramsay and Cooper, 2002).Bars indicate 2 sigma ranges of calibrated radiocarbon dates, average ages calculated, right: SST fluctuations in °C (Bard et al., 1997) for core MD79257 in the Mozambique Channel and climatic interpretations according to pollen data (thisstudy).

50F.H

.Neum

annet

al./Review

ofPalaeobotany

andPalynology

162(2010)

39–53

image of Fig.�5


high rainfall was obviously favourable for the expansion of mangroveand swamp forests, which now occur at the St. Lucia estuary and closeof the shores of Lake St. Lucia ca. 25 km to the east of the site (Fig. 1). Itshould be noted that some elements of the coastal forest as well as theswamp forest, e.g., Syzygium and Rauvolfia, can also occur in LowveldRiverine Forest, which can be found at the river banks of the Ngweni,ca. 70 km to the north of Lake Eteza (Fig. 1). We therefore postulate adense mosaic and a mixture of different forest types with somegrassland and abundant wetlands for the time period 6800–3600 cal yrs BP.

5.4. Correlation to sea level fluctuations in South Africa

Ramsay (1995) and Ramsay and Cooper (2002) providedestimates of Holocene sea level fluctuations in southern Africa thatare based on a series of radiocarbon dates on shells, corals, calcareousalgae and wood attached to beach rocks and pothole fills, which wecalibrated here for comparison with the Eteza sequence using theCalib 5.0.2/ calibration set: marine 04.14c (Figs. 5, 2 σ ranges).Twenty-two radiocarbon dates represent the time period between491.5 cal yrs BP and 9610 cal yrs BP, paralleling the Lake Eteza andLake Sibaya sequences. No reliable sea level data are availablebetween 3209.5 and 1146.5 cal yrs BP, which might be explained bya lower sea level than today (Ramsay, 1995) based on Holocene beachrocks at ca. 2 m below the modern sea level, with an estimated date ofca. 3000 cal yrs BP (Ramsay, 1995; Ramsay and Cooper, 2002).

Since about 17000 cal yrs BP a continuous sea level increase isrecorded following thermal expansion and melting ice of the LastGlacial maximum phase (Ramsay and Cooper, 2002; Pugh, 2004). Thesea level rose from about−28 m bsl. at ca. 9610 cal yrs BP and reachescurrent levels by 6952.5 cal yrs BP (Fig. 5). Similar sea level increaseswere also observed in Mozambique, Groenvlei, Elands Bay (WesternCape) and at the SW coast of Namibia (Martin, 1968; Jaritz et al. 1977;Miller et al., 1995; Compton, 2006). The sea level increase is paralleledby an increase of SST in the Mozambique Channel (Fig. 5) (Bard et al.,1997).

The Lake Eteza pollen record from its start ca. 7000 cal yrs BPwhenthe sea level must have been lower, suggests gradually dryingconditions with prominent Cheno/Ams and Poaceae percentageswith less tree cover (Fig. 5). The mid Holocene humid phase ischaracterized by a steady increase of the sea level curve for southernAfrica until a maximum high stand of +3.5 m abovemodern sea level,was reached 4653 cal yrs BP (Ramsay, 1995). The high stand was dueto a combination of isostatic emergence and the steric expansion ofseawater relating to warmer temperatures (Ramsay, 1995) and anincrease of humidity and higher temperatures during the midHolocene (Tyson and Preston-Whyte, 2004; Partridge, 1997). Be-tween ca. 7000 and 4200 cal yrs BP, SST in the Mozambique Channelare N27 °C, underlining that steric expansion played a crucial role forhigh sea levels during this period. These favourable climatic condi-tions with an increase in rainfall, find support in the high percentagesof trees, esp. Podocarpus and swamp forest vegetation along theKwaZulu-Natal coast. Even though evidence for an increase inmoisture is given in the pollen record, pollen alone does not provideproof of increased temperatures. Although clear indicators for marineinfluence are missing, strong values of mangrove trees, e.g. Bruguieria,suggest that the coast was closer to Lake Eteza during the MiddleHolocene.

The Late Holocene sea level curve of southern Africa since ca.4000 cal yrs BP is marked by a decrease with aminimum of 2 m belowthe modern sea level at ca. 3000 cal yrs BP (Ramsay, 1995, Fig. 5). SSTvalues from the Mozambique Channel are also decreasing since ca.4200 cal yrs BP, showing a generally similar trend in SST and sea levels.In contrast, a more gradual increase of the sea level 5500 to 3000 BP isreconstructed by Compton (2006) for the SW coast of Namibia.

6. Conclusion

The Lake Eteza pollen sequence presents a detailed picture aboutthe climate driven vegetation development in coastal KwaZulu-Natalthat can be linked to SST and sea level fluctuations in the region. Thiscontributes to the knowledge about climatic variability in easternSouth Africa helping to place regional climatic events in global climatecontext e.g., the role of the precession cyclewhich have been proposedas a major driver for moist conditions in Southern Africa (Kutzbach,1981; Street-Perrot and Perrot, 1993; Partridge et al., 1997) that is outof phase with Northern Hemisphere and which according to themodel, should be manifested in the Southern Hemisphere tropics in agenerally dry early Holocene. Although weakening of precessionalamplitude is indicated over the last 30000 years (Berger and Loutre,1991) there is nevertheless evidence for a dry early Holocene in SouthAfrica (Scott and Lee-Thorp, 2004) but its role has been questioned byrecent evidence suggesting amoist early Holocene (Chase et al., 2009).

At Lake Eteza, the period between 10200 and 6800 cal yrs BP ischaracterised by the shift from wetter woodland to a dry grassierenvironment coinciding with rising SST and sea levels in theMozambique Channel. The slightly wetter conditions at the start ofthe Holocene do notmatch the precession cycle precisely. A low of SSTin the Mozambique Channel could, however, have caused a rather dryperiod in coastal KwaZulu-Natal between 8000 and 7000 cal yrs BPresulting in extraordinarily high grass percentages and very low treevalues. The early rather wet phase at Eteza seems slightly out of phasewith the period of relatively low SST, but we needmore palaeoclimatedata in eastern South Africa to link this event in the Eteza record to aglobal cooling event, which peaked ca. 8200 cal yrs BP in the NorthernHemisphere, and led to aridity in the low latitudes and a weak polaratmospheric circulation over East Antarctica (compare Mayewskiet al., 2004).

AhumidmiddleHolocenephasebetweenca. 6800and3600 cal yrs BPis represented by high tree percentages, esp. Podocarpus. Mangrove andswamp forest elements probably indicate a high groundwater table and ashort distance to the coast of the Indian Ocean, which is a direct result ofhigher rainfall enhanced by higher SST's and a higher sea level. Theoccurrence of freshwater molluscs since ca. 4700 cal yrs BP and anabundance of aquatics and swamp plants indicate a humid, freshwaterdominated environment. SST's are high in the Mozambique Channel ca.7000–4000 cal yrs BP, inducing a southward penetration of the Agulhascurrent and an increase of precipitation in coastal KwaZulu-Natal. Thismoist period, however, weakens with higher Poaceae and Phoenixpercentages ca. 6000–5000 cal yrs BP in correspondence with slightlylower SST but continuous high sea levels. Sudden events of highsedimentation rate ca. 6500 and 4000 cal yrs BP can tentatively beexplained as flood events comparably to the one caused by a cyclone in1984 (Domoina).

Dry conditions occurred after ca. 3600 cal yrs BP and might haveled to the decline of most trees including Podocarpus and the increaseof Poaceae and Phoenix between ca. 3500 and 2500 cal yrs BP. Cheno/Ams and Asteraceae might support the hypothesis of comparably aridwooded grassland. Mayewski et al. (2004) describe an event between3500 and 2500 cal yrs BP which caused aridity in Eastern Africa and isprobably related to the establishment of dry environmental condi-tions in coastal KwaZulu-Natal. SST data are not available from thisperiod but the sea level dropped, probably as a result of cooler anddrier conditions. The Podocarpus decline can be observed in a numberof localities in KwaZulu-Natal since ca. 3100 cal yrs BP and is thereforea regional phenomenon and strongly linked to drying in the LateHolocene. A renewed spread of Phoenix and Poaceae occurred ca.2500 cal yrs BP onward suggesting a continuation of the trend.

The upper part of the profile since ca. 700 cal yrs BP shows dramaticvegetation changes, especially the drastic decline of Podocarpus andother trees and the expansion of Poaceae and neophytes, probablyindicating humandisturbances by the first IronAge settlers in KwaZulu-


Natal. This period coincides with the onset of the Little Ice Age,characterised in eastern South Africa by a cold and dry period, which isalso reported from tree-ring data in KwaZulu-Natal (Huffman, 1996;Vogel et al., 2001; Holmgren et al., 2003). Pollen records of two lakes insouthernMozambique also show a forest decline connected to the LittleIce Age. Although the resolution before ca. 370 cal yrs BP in the LakeEteza record is not high enough for more detailed considerations, itseems that the Iron Age settlers arrived in an environment when thePodocarpus forestswere already in decline allowing Iron Age cultivationand herding in a more open landscape. The current sea level is reachedagain between ca. 270 and 755 cal yrs BP after which the area aroundLake Eteza and Lake Sibaya is continually influenced by human impact.

We connect the extremely low tree percentages and the spread ofgrasses after ca. 700 cal yrs BP to a combination of unfavourable cli-matic conditions and human pressure. In Neumann et al. (2008) onlyanthropogenic impact was postulated as the reason for the mostrecent decrease of Podocarpus. However, further high resolutionmulti-proxy studies are necessary to understand the contribution ofIron Age settlers to landscape transformation to its full extent.Another aspect is that, although an earlier occupation by farmingcommunities is likely, no evident vegetation changes were observed.After the introduction of maize by Iron Age people in the 17th century,an increase of neophyte pollen is indicated together with Europeancolonisation. Exotic Pinus, Eucalyptus and sugar cane plantations wereestablished in the 19th century in KwaZulu-Natal. An increase of thesedimentation rate, probably due to erosion, underlines the degrada-tion of the landscape.

Finally this paper demonstrates the value of combining pollenanalyses with vegetation modelling by supporting the work of Eeleyet al. (1999). In turn the modelling results might give a better insightof what the pollen spectra at Lake Eteza might mean by suggesting ofmixing of currently isolated forest types in the Kwazulu-Natal regionunder Middle Holocene conditions.

Acknowledgements

Thepalynologicalworkwas supported by apostdoctoral fellowshipto F. Neumann from the National Research Foundation/South Africa(NRF) at the University of the Free State and from a postdoctoral grantof the University of theWitwatersrand.We thank C. Stager for lookingfor diatoms in our samples, andG.Whitelaw,M. Langer,M. Bamford, K.Sadr and A. Yates for helpful discussions. Marianna Smith (neeSteenkamp) assisted with initial pollen counts. Drs. R. Maud, and G.Botha, and Mr. P. Rheeder are thanked for initial advice and supportwith the coring operation in 1992.We are also indebted toMr.M. Brinkand family accommodation at that time. The NRF (GUN 2053236)supported L. Scott. Any opinions, findings, and conclusions are those ofthe authors and the NRF does not accept any liability in regard thereto.This article benefitted greatly from the comments and suggestions byH. Lamb and an anonymous reviewer. A. Yates has thankfully correctedthe English of our manuscript. P. Chakane processed the samples.

References

Abbot, R.T., 1973. Spread of Melanoides tuberculata. The Nautilus 87 (1), 29.Allanson, B.R., Baird, D., 1999. Estuaries of South Africa. Cambridge University Press,

Cambridge.Bard, E., Rostek, F., Sonzogni, C., 1997. Interhemispheric synchrony of the last

deglaciation inferred from alkenone palaeothermometry. Nature 385, 707–710.Barron, J.A., 1993. Diatoms. In: Lipps, J.H. (Ed.), Fossil Prokaryotes and Protists.

Blackwell Sciences, pp. 155–167.Beesley, P.L., Ross, G.J.B., Wells, A., 1998. Mollusca: the southern synthesis. Fauna of

Australia, vol. 5. CSIRO Publishing, Melbourne, pp. 565–1234. Part B.Begg, G., 1989. The wetland of Natal. The Location, Status and Function of the Priority

Wetlands of Natal: Natal Town and Regional Planning Report 73.Berger, A., Loutre, M.F., 1991. Insolation values for the climate of the last 10 million

years. Quaternary Sciences Review 10, 297–317.

Berjak, P., Campbell, G.K., Huckett, B.I., Pammenter, N.W., 1997. In the Mangroves ofSouthern Africa. KwaZulu-Natal Region of the Wildlife and Environment Society ofSouth Africa, Durban.

Bonnefille, R., Riollet, G., 1980. Pollens des Savanes ďAfrique Orientale. Editions duCentre National de la Recherche Scientifique, Paris.

Bousman, C.B., 1998. The chronological evidence for the introduction of domestic stockinto Southern Africa. African Archaeological Review 15 (2), 133–150.

Branch, G.M., Griffiths, C.L., Branch, M.L., Beckley, L.E., 2007. Two oceans. A Guide to theMarine Life of Southern Africa. Struik Publishers, Cape Town, South Africa.

Bronk Ramsey, C., 2008. Deposition models for chronological records. QuaternaryScience Reviews 27 (1–2), 42–60.

Bronk Ramsey, C., 2009. Bayesian analysis of radiocarbon dates. Radiocarbon 51 (1),337–360.

Brown, D.S., Curtis, B.A., Rollinson, D., 1996. The freshwater snail Bulinus tropicus(Planorbidae) in Namibia, characterised according to chromosome number,enzymes and morphology. Hydrobiologia 317 (1), 27–139.

Bruton, M.N., Smith, M., Taylor, R.H., 1980. A brief history of human evolvement inMaputaland. In: Bruton, M.N., Cooper, K.H. (Eds.), Studies on the Ecology ofMaputaland. Rhodes University and the Natal Branch of the Wildlife Society ofSouthern Africa, Durban, pp. 432–459.

Chase, B.M., Meadows, M.E., Scott, L., Thomas, D.S.G., Marais, E., Sealy, J., Reimer, P.J.,2009. A record of rapid Holocene climate change preserved in hyrax middens fromsouthwestern Africa. Geology 37, 703–706.

Chase, B.M., Meadows, M.E., Carr, A.S., Reimer, P.J., 2010. Evidence for progressiveHolocene aridification in southern Africa recorded in Namibian hyrax middens:implications for African monsoon dynamics and the ‘African Humid Period’.Quaternary Research. doi:10.1016/j.yqres.2010.04.006.

Coates-Palgraves, M., 2002. Trees of Southern Africa. Struik Publishers, Cape Town.Compton, J.S., 2006. The mid-Holocene sea-level highstand at Bogenfels Pan on the

southwest coast of Namibia. Quaternary Research 66, 303–310.De Menocal, P., Ortiz, J., Guilderson, T., Sarnthein, M., 2000. Coherent high- and low-

latitude climate variability during the Holocene warm period. Science 288,2198–2202.

DeJager, J.M., Schulze, R.E., 1977. The broad geographic distribution in Natal ofclimatological factors important to agricultural planning. Agrochemophysica 9, 81–91.

Delegorgue, A., 1990. Travels in Southern Africa, volume I. University of Natal Press,Pietermaritzburg, pp. 222–223. translated by F. Webb.

Dyer, R.A., 1975. The genera of Southern African flowering plants. Dicotyledons, vol. 1.Department of Agricultural Technical Services, Pretoria.

Eeley, H.A.C., Lawes, M.J., Piper, S.E., 1999. The influence of climate change on thedistribution of indigenous forest in KwaZulu-Natal, South Africa. Journal ofBiogeography 26, 595–617.

Ekblom, A., 2004. Changing landscapes—an environmental history of Chibuene,Southern Mozambique. Studies in Global Archaeology, 5. Department of Archae-ology and Ancient History, Uppsala.

Ekblom, A., 2008. Forest-savanna dynamics in the coastal lowland of southernMozambique since c. AD 1400. The Holocene 18 (8), 1247–1257.

Faegri, K., 1993. Bestimmungsschluessel fuer die nordwesteuropaeische Pollenflora.Gustav Fischer Verlag, Jena.

Faegri, K., Iversen, J., 1993. Bestimmungsschlüssel für die nordwesteuropäischePollenflora. Gustav Fischer Verlag, Stuttgart, New York.

Finch, J.M., 2005. Late Quaternary palaeoenvironments of the Mfabeni peatlands, northernKwaZulu-Natal. Unpubl. Master thesis, University of KwaZulu-Natal, Pietermaritzburg.

Finch, J.M.,Hill, T.R., 2008. A lateQuaternarypollensequence fromMfabeni Peatland, SouthAfrica: reconstructing foresthistory inMaputaland.Quaternary Research70, 442–450.

Finné, M., Norström, E., Risberg, J., Scott, L., 2010. Siliceous microfossils as late-Quaternary palaeo-environmental indicators at Braamhoek wetland, South Africa.The Holocene. doi:10.1177/0959683610362810 (April 22).

Germishuizen, G., Meyer, N.L., 2003. Plants of Southern Africa, an Annotated Checklist.Strelitzia, vol. 14. National Botanical Institute, Pretoria.

Grenfell, S.E., Ellery, W.N., Grenfell, M.C., 2009. Geomorphology and dynamics of theMfolozi Riverfloodplain, KwaZulu-Natal, South Africa. Geomorphology 107, 226–240.

Grundling, P., Mazus, H., Baartman, L., 1998. Peat Resources in Northern KwaZulu Natal:SouthMaputaland. Dept. of Environmental Affairs and Tourism, Pretoria, pp. 1–102.

Hall, M., 1980. Man's role in the development of threatened habitats. HABCON.WorkingDocument, vol. 5. CSIR, Pretoria.

Haug, G.H., Hughen, K.A., Sigman, D.M., Peterson, L.C., Roehl, U., 2001. Southwardmigration of the Innertropical Convergence Zone through the Holocene. Science293, 1304–1308.

Holmgren, K., Lee-Thorp, J.A., Cooper, G.R.J., Lundblada, K., Partridge, T.C., Scott, L.,Sithaldeen, R., Talma, A.S., Tyson, P.D., 2003. Persistent millennial-scale climaticvariability over the past 25,000 years in Southern Africa. Quaternary ScienceReviews 22, 2311–2326.

Howard-Williams, C., 1980. Aquatic macrophytes of the coastal wetlands of Maputa-land. In: Bruton, M.N., Cooper, K.H. (Eds.), Studies on the Ecology of Maputaland.Rhodes University and The natal Branch of the Wildlife Society of Southern Africa,Durban, pp. 42–51.

Huffman, T.N., 1982. Archaeology and ethnohistory of the African Iron Age. AnnualReview of Anthropology 11, 133–150.

Huffman, T.N., 1996. Archaeological evidence for climatic change during the last2000 years in southern Africa. Quaternary International 33, 55–60.

Huffman, T.N., 2006. Maize grindstones, Madikwe pottery and ochre mining inprecolonial South Africa. Southern African Humanities 18 (2), 51–70.

Huffman, T.N., 2007. Handbook to the Iron Age. The Archaeology of Pre-ColonialFarming Societies in Southern Africa. University of KwaZulu Natal Press, Scottsville,South Africa.


Jaritz, W., Ruder, J., Schlenker, B., 1977. Das Quartär im Küstengebiet von Mozambiqueund seine Schwermineralführung. Geologisches Jahrbuch 26, 3–93 (In German).

Jury, M.R., 1998. Statistical analysis and prediction of KwaZulu-Natal climate. Theor.Appl. Climatol. 60, 1–10.

Jury, M.R., Pathack, B.M.R., 1993. Composite climatic patterns associated with extrememodes of summer rainfall over Southern Africa: 1975–1984. Theor. Appl. Climatol.47, 137–145.

Jury, M.R., Valentine, H., Lutjeharms, J.R.E., 1993. Influence of the Agulhas Current onsummer rainfall along the southeast coast of South Africa. Journal of AppliedMeteorology 32 (7), 1282–1287.

Jury, M.R., Parker, B., Waliser, D., 1994. Evolution and variability of the ITCZ in the SWIndian Ocean: 1988–1990. Theor. Appl. Climatol. 48, 187–194.

Jury, M.R., Enfield, D.B., Mélice, J.-L., 2002. Tropical monsoons around Africa: stability ofEl Niño–Southern Oscillation associations and links with continental climate.J. Geophys. Res. 107 (C10), 3151.

Kotze, D.C., O'Connor, D.G., 2000. Vegetation variation within and among palustrinewetlands along an altitudinal gradient in KwaZulu-Natal, South Africa. PlantEcology 146, 77–96.

Kotze, D.C., Breen, C.M., Quinn, N., 1995. Wetland losses in South Africa. In: Cowan, G.I.(Ed.), Wetlands of South Africa. Department of Environmental Affairs and Tourism,Pretoria.

Kutzbach, J.E., 1981. Monsoon climate of the early Holocene climate experiment usingthe Earth's orbital parameters for 9000 years ago. Science 214, 59–61.

Lindsay, P., Mason, T.R., Pillay, S., Wright, C.I., 1996. Suspended particulate matter anddynamics of the Mfolozi estuary, Kwazulu-Natal: implications for environmentalmanagement. Environmental Geology 28 (1), 40–51.

Lutjeharms, J.R.E., Monteiro, P.M.S., Tyson, P.D., Obura, D., 2001. The oceans aroundsouthern Africa and regional effects of global change. South African Journal ofScience 97.

MacDevette, D.R., 1989. The vegetation and conservation of the Zululand coastal dunes.In: Gordon, I.G. (Ed.), Natal Indigenous Forests. Natal Park Board, Pietermaritzburg.

Martin, A.R.H., 1968. Pollen analysis of Groenvlei lake sediments, Knysna (South Africa).Reviews of Palaeobotany and Palynology 7, 107–144.

Marwick, C.W., 1973. Kwamahlati. Die verhaal van bosbou in Zululand. Bulletin, 49.Department of Environment and Forestry, Pretoria.

Maud, R.R., 2000. Estuarine deposits. In: Partridge, T.C., Maud, R.R. (Eds.), The Cenozoicof Southern Africa. Oxford University Press, NewYork, pp. 162–172.

Mayewski, P.A., Rohling, E.E., Stager, J.C., Karlen, W., Maascha, K.A., Meekere, L.D.,Meyerson, E.A., Gasse, F., van Kreveld, S., Holmgren, H., Lee-Thorph, J., Rosqvist, G.,Racki, F., Staubwasser, M., Schneider, R.R., Eric, J., Steigl, E.J., 2004. Holocene climatevariability. Quaternary Research 62, 243–255.

Mazus, H., 2000. Clues on the history of Podocarpus forest in Maputaland, South Africa,during the Quaternary, based on pollen analysis. Africa Geosciences Review 7 (1),75–82.

McCann, J.C., 2005. Maize and Grace: Africa's Encounter with a New World Crop 1500–2000. Harvard University Press, Cambridge.

Miller, W.R., 2001. The bathymetry, sedimentology, and seismic stratigraphy of LakeSibaya-Northern KwaZulu-Natal. Bulletin, 131. Council for Geoscience, Pretoria.

Miller, D.E., Yates, R.J., Jerardino, A., Parkington, J.E., 1995. Late Holocene coastal changein the Southwestern Cape, South Africa. Quaternary International 29 (30), 3–10.

Mucina, L., Geldenhuys, C.J., 2006. Afrotemperate, subtropical and azonal forests. In:Mucina, L., Rutherford, M.C. (Eds.), The Vegetation of South Africa, Lesotho andSwaziland. Strelitzia, vol. 19. South African National Biodiversity Institute, Pretoria,pp. 585–614.

Mucina, L., Rutherford, M.C., 2006. The vegetation of South Africa, Lesotho andSwaziland. Strelitzia, vol. 19. South African National Biodiversity Institute, Pretoria.

Mucina, L., Scott-Shaw, C.R., Rutherford, M.C., Kemp, K.G.T., Matthews, W.S., Powrie, L.W.,Hoare, D.B., 2006. IndianOcean coastal belt. In:Mucina, L., Rutherford,M.C. (Eds.), TheVegetation of South Africa, Lesotho and Swaziland. : Strelitzia, vol. 19. South AfricanNational Biodiversity Institute, Pretoria, pp. 569–583.

Neck, R.W., 1985. Melanoides tuberculata in extreme Southern Texas. Texas Conchol-ogist 21 (4), 150–152.

Neumann, F.H., Stager, J.C., Scott, L., Venter, H.J.T., Weyhenmeyer, C., 2008. Holocenevegetation and climate records from Lake sibaya, KwaZulu-Natal (South Africa).Review of Palaeobotany and Palynology 152, 113–128.

Norström, E., Scott, L., Partridge, T.C., Risberg, J., Holmgren, K., 2009. Reconstruction ofenvironmental and climate changes at Braamhoek wetland, eastern escarpmentSouth Africa, during the last 16,000 years with emphasis on the Pleistocene–Holocene transition. Palaeogeography, Palaeoclimatology, Palaeoecology 271,240–258.

Oschadleus, H.D., Vogel, J.C., Scott, L., 1996. Radiometric date for the Port Durnford peatand development of yellow-wood forest along the South African east coast. SouthAfrican Journal of Science 92, 43–45.

Partridge, T.C., 1997. Cainozoic environmental change over southern Africa, withspecial emphasison the last 20 000 years. Progress in Physical Geography 21, 3–22.

Partridge, T.C., Demenocal, P.B., Lorentz, S.A., Paiker, M.J., Vogel, J.C., 1997. Orbitalforcing of climate over South Africa: a 200 000-year rainfall record from thePretoria Saltpan. Quaternary Science Reviews 16, 1–9.

Pooley, E., 1993. The Complete Field Guide to Trees of Natal, Zululand and Transkei.Natal Flora Publication Trust, Durban.

Pooley, E., 2005. A Field Guide to Wildflowers KwaZulu-Natal and the Eastern Regions.Natal Flora Publication Trust, Durban.

Pugh, D., 2004. Changing Sea Levels. Cambridge University Press, Cambridge.Ramsay, P.J., 1995. 9000 years of sea-level change along the southern African coastline.

Quaternary International 31, 71–75.Ramsay, P.J., Cooper, J.A.G., 2002. Late Quaternary sea-level changes in South Africa.

Quaternary Research 57, 82–90.Roberts, D.L., Botha, G.A., Maud, R.R., Pether, J., 2006. Coastal Cenozoic deposits. In:

Johnson, M.R., Anhaeusser, C.R., Thomas, R.J. (Eds.), The Geology of South Africa.Council for Geosciences, Pretoria, pp. 585–604.

Roessler, M.A., Beardsley, G.L., Tabb, D.C., 1977. New records of the introduced snail,Melanoides tuberculata (Mollusca: Thiaridae) in south Florida. Florida Scientist 40,87–94.

Ross, J.H., 1971. The Acacia species of Natal—an introduction to the idigenuous species.The Natal Branch of the Wildlife Protection and Conservation Society of SouthAfrica, Durban.

Rutherford, M.C., Mucina, L., Lötter, M.C., Bredenkamp, B.J., Smit, J.H.L., Scott-Shaw, C.R.,Hoare, D.B., Goodman, P.S., Bezuidenhout, H., Scott, L., Ellis, F., Powrie, L.W., Siebert, F.,Mostert, T.H., Henning, B.J., Venter, C.E., Camp, K.G.T., Siebert, S.J., Matthews, W.S.,Burrows, J.E., Dobson, L., van Rooyen, N., Schmidt, E.,Winter, P.J.D., du Preez, P.J., ward,R.A.,Williamson, S., Hurter, P.J.H., 2006. Savanna Biome. In:Mucina, L., Rutherford,M.C.(Eds.), The Vegetation of South Africa, Lesotho and Swaziland. Strelitzia, vol. 19. SouthAfrican National Biodiversity Institute, Pretoria, pp. 439–539.

Schulze, B.R., 1965. General survey. Climate of South Africa. Series Part 8. WeatherBureau Publications, Department of Transport, Pretoria.

Schulze, R.E., 1982. Agrohydrology and climatology of Natal. Technical Report ACRU, 14.Department Agricultural Engineering, Pietermaritzburg.

Scott, L., 1982. Late Quaternary fossil pollen grains from the Transvaal, South Africa.Review of Palaeobotany and Palynology 36, 241–278.

Scott, L., 2002. Microscopic charcoal in sediments and Late Quaternary fire history of thegrassland and savanna regions in Africa. Journal of Quaternary Science 17 (1),77–86.

Scott, L., Lee-Thorp, J.A., 2004. Holocene climatic trends and rythms in South Africa. In:Battarbee, R.W., Gasse, F., Stickley, C.E. (Eds.), Past Climate Variability throughEurope and Africa. Springer, Dordrecht, pp. 69–78.

Scott, L., Steenkamp, M., 1996. Environmental history and recent human disturbance atcoastal Lake Teza, Kwazulu/Natal. South African Journal of Science 92, 348–350.

Scott, L., Cooremans, B., Maud, R.R., 1992. Preliminary palynological evaluation of thePort Durnford Formation at Port Durnford, Natal coast, South Africa. South AfricanJournal of Science 88, 470–474.

Shaughnessy, G., 1986. A case study of some woody plant introductions to the CapeTown area. In: Macdonald, I.A.W., Kruger, F.J., Ferrar, A. (Eds.), The Ecology andManagement of Biological Invasions in Southern Africa. Oxford University Press,Cape Town, pp. 37–44.

Street-Perrot, A.F., Perrot, R.A., 1993. Holocene vegetation, lake levels, and climate ofAfrica. In: Wright, H.E., Kutzbach, J.E., Webb, T., Ruddiman, W.E., Street, F.A.,Bartlein, P.J. (Eds.), Global Climates Since the Last Glacial Maximum. University ofMinnesota Press, Minneapolis, pp. 318–356.

Thamm, A.G., Grundling, P., Mazus, H., 1996. Holocene and recent peat growth on theZululand Coastal Plain. Journal of African Earth Science 23 (1), 119–124.

Turner, S., Plater, A., 2004. Palynological evidence for the origin and development of lateHolocene wetland sediments: Mdlanzi swamp, KwaZulu-Natal, South Africa. SouthAfrican Journal of Science 100, 220–229.

Tyson, P.D., Preston-Whyte, R.A., 2004. The Weather and Climate of southern Africa.Oxford University Press, Oxford.

Vogel, J.C., 1995. The temporal distribution of radiocarbon dates for the Iron Age insouthern Africa. South African Archaeological Bulletin 50, 106–109.

Vogel, J.C., Fuls, A., Visser, E., 2001. Radiocarbon adjustments to the dendrochronologyof a yellowwood tree. South African Journal of Science 97, 164–166.

Walker, B.H., 1980. A review of browse and its role in livestock production in SouthernAfrica. In: Le Houérou, H.N. (Ed.), Browse in Africa, the Current State of Knowledge.ILCA Addis Ababa, Ethiopia.

Walker, N.D., 1990. Links between South African summer rainfall and temperaturevariability of the Agulhas and Benguela Current systems. Journal of GeophysicalResearch 95, 3297–3319.

West, A.G., Midgley, J.J., Bond, W.J., 2000. Regeneration failure and the potentialimportance of human disturbance in a subtropical forest. Applied VegetationScience 3 (2), 223–232.

Williams, R., 1921. The Cape to Cairo railway. Journal of the African Societies 20 (35),1–20.

Wright, C.I., Cooper, J.A.G., Kilburn, (Dick) R.N., 1999. Mid Holocene palaeoenviron-ments from Lake Nhlange, Northern Kwazulu-Natal, South Africa. Journal of CoastalResearch 15 (4), 991–1001.

Wright, C.I., Miller, W.R., Cooper, J.A.G., 2000. The late Cenozoic evolution of coastalwater bodies in Northern KwaZulu-Natal, South Africa. Marine Geology 167,207–229.

A Holocene sequence of vegetation change at Lake Eteza, coastal KwaZulu-Natal, South Africa

Documents

Transcript of A Holocene sequence of vegetation change at Lake Eteza, coastal KwaZulu-Natal, South Africa