# Fire drives major Holocene vegetation shifts between subtropical and Mediterranean-type ecosystems: a case study from a biodiversity hotspot in South Africa

Lynne Quick, Brian Chase, Manuel Chevalier, B. Adriaan Grobler, Saúl Manzano

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## To cite this version:

Lynne Quick, Brian Chase, Manuel Chevalier, B. Adriaan Grobler, Saúl Manzano. Fire drives major Holocene vegetation shifts between subtropical and Mediterranean-type ecosystems: a case study from a biodiversity hotspot in South Africa. Ecography, 2024, 2024 (12), pp.e07485. 10.1111/ecog.07485. hal-04717259

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ECOGRAPHY

Research article

# Fire drives major Holocene vegetation shifts between subtropical and Mediterranean-type ecosystems: a case study from a biodiversity hotspot in South Africa

Lynne J. Quick ID, Brian M. Chase ID 2,3, Manuel Chevalier ID 4, B. Adriaan Grobler ID 1 and Saúl Manzano ID 1,5,6

**Correspondence:** Lynne J. Quick (lynne.j.quick@gmail.com)

## Ecography

2024: e07485

doi: 10.1111/ecog.07485

Subject Editor: Elizabeth Le Roux

Editor-in-Chief: Miguel Araújo

Accepted 8 July 2024

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Fire plays a pivotal role in driving ecological shifts between Mediterranean-type vegetation and subtropical ecosystems in South Africa. This study investigates long-term environmental dynamics and ecological regime changes at the Mediterranean-type vegetation /subtropical boundary using a 6000-year palaeoecological sequence from the Baviaanskloof – a region of South Africa characterized by high levels of biodiversity and climate dynamism. Combining fossil pollen and microcharcoal data from a rock hyrax *Procavia capensis* midden, we analyse vegetation responses to environmental changes. Our findings reveal that Mediterranean-type vegetation resilience prevailed until ca 2800 cal year BP when a major fire event triggered a transition to a subtropical thicket-dominated environment. This abrupt ecological turnover underscores the significance of fire as a major driver of vegetation change at the Mediterranean-type vegetation /subtropical boundary. Our study emphasizes the vulnerability of Mediterranean-type vegetation ecosystems to global environmental change, suggesting potential implications for similar biome boundaries worldwide. By integrating multi-proxy palaeoecological evidence, we gain insights into the resilience and vulnerability of these ecosystems, aiding in understanding future responses to climate change scenarios.

Keywords: Cape Floristic Region, ecological regime shifts, long-term environmental dynamics, palaeoecology, South Africa

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<footnote n="1">¹African Centre for Coastal Palaeoscience, Nelson Mandela University, Gqeberha, South Africa</footnote>

<footnote n="2">²Institut des Sciences de l'Evolution-Montpellier (ISEM), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), EPHE, IRD, Montpellier, France</footnote>

<footnote n="3">³Department of Environmental and Geographical Science, University of Cape Town, South Lane, Upper Campus, Rondebosch, South Africa</footnote>

<footnote n="4">⁴Institute of Geosciences, Sect. Meteorology, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany</footnote>

<footnote n="5">⁵Área de Botánica, Depart. Biodiversidad y Gestión Ambiental, Facultad de Ciencias Biológicas y Ambientales, Campus de Vegazana, Universidad de León, León, España</footnote>

<footnote n="6">⁶Quaternary Palynology Lab, Insituto de Medio Ambiente, Recursos Naturales y Biodiversidad, Universidad de León, León, España</footnote>
## Introduction

Southern Africa hosts a unique mosaic of biomes distrib-
uted in relation to temperature and rainfall amount and
seasonality. In South Africa there are three global-scale bio-
diversity hotspots: the Cape Floristic Region (dominated
Mediterranean-type vegetation, MTV), the Succulent Karoo
(vegetated by a succulent desert) and the Maputaland-
Pondoland-Albany centre of endemism (dominated by sub-
tropical evergreen thicket vegetation, Myers et al. 2000). In
the face of accelerated global environmental change, biodi-
versity hotspots represent a global priority, making South
Africa a key geographical region for nature conservation. In
this context, a deep understanding of community response
to environmental controls is fundamental to assess ecologi-
cal responses to different models of landscape governance
(Steffen et al. 2018). However, experimental or observational
data on timings and trends of community responses are insuf-
ficient, since many active drivers of environmental change
operate at longer palaeoecological time scales (Gillson and
Marchant 2014).

Within the broader context of southern African palaeoen-
vironmental research, previous research on palaeoecological
change and its drivers primarily relied on mechanistic cli-
mate models (van Zinderen Bakker 1976, Cockcroft et al.
1987). However, the acquisition of high-resolution data
has revealed much greater complexity than predicted by
the early models, where not only climate, but fire is a key
environmental driver (Gillson et al. 2020, Pausas and Bond
2020, Manzano et al. 2023). This is particularly evident for
the southern Cape, where recent studies have highlighted
complex patterns of hydroclimate change at subregional
scales (Chase et al. 2013, 2017, 2020, Chase and Quick
2018), provoking contrasting responses in different eco-
logical communities, sometimes in association with chang-
ing fire dynamics (Gillson et al. 2020). While these recent
studies have significantly improved the temporal and spatial
resolution of the palaeoenvironmental record, more data
are required to fully explore the landscape-scale nature of
southern Cape environmental change and its impact on
biodiversity dynamics, in particular when these pertain to
major ecological shifts and vegetation turnovers that can-
not be predicted solely from changes in hydroclimate or
temperature.

The aim of this work is to identify such mechanisms
that may drive long-term environmental dynamics and eco-
logical regime shifts at the Mediterranean-type/Subtropical
ecosystem boundary. Here we present a 6000-year palaeo-
ecological sequence comprising of fossil pollen and micro-
charcoal data from a rock hyrax *Procavia capensis* midden
(see Chase et al. 2012 for a description of this unique pal-
aeoenvironmental archive) from the Baviaanskloof region
of the southern Cape. Here, the Cape Floristic Region, the
Succulent Karoo and the Maputaland-Pondoland-Albany
hotspots coalesce and is thus considered to be a region where
ecological systems are likely to be more sensitive to environ-
mental change.

## Regional setting and site description

Situated in South Africa's Eastern Cape province and form-
ing part of the eastern interior subregion of the southern
Cape, the Baviaanskloof occupies an important transition
zone between the arid interior of the country and the rela-
tively mesic coastal lowlands (Fig. 1). The Baviaanskloof is
a narrow ~ 70 km-long, fault-bounded valley situated ~ 55
km to the north of the coast between the east-west running
Baviaanskloof and Kouga mountain ranges (Fig. 1).

The Baviaanskloof is characterized by complex climate
dynamics, falling within the aseasonal rainfall zone (ARZ;
33-66% of mean annual precipitation occurring during the
winter, sensu Chase and Meadows 2007), and being influ-
enced by both temperate and tropical climate systems. The
region is topographically complex, and is characterised by
geological and geomorphological heterogeneity, producing
steep environmental and ecological gradients. Valley floor
elevation decreases from 800 m a.s.l. in the west to 250 m
a.s.l. in the east with the bounding mountain ranges reaching
above 1000 m a.s.l. Rainfall can vary between 200-800 mm
per year (and as part of the ARZ, can occur at any time of the
year) and maximum temperatures can be above 40°C in sum-
mer and below 0°C in the winter with snow on the mountain
peaks (Euston-Brown and Kruger 2023).

## Vegetation

Several of South Africa's biomes converge in the Baviaanskloof, incorporating subtropical, Afromontane and Cape Floristic Region vegetation types as well as Nama Karoo elements (Boshoff 2005, Fig. 1). The subtropical and Afromontane elements assemble either into Afrotemperate forest patches or subtropical thickets, and representatives of the Cape Floristic Region which are extraordinarily rich in endemic genera and species, assemble into MTV, in particular fine-leaved heathlands (fynbos) and shrublands (renosterveld) (Fig. 1). This complex mosaic of vegetation types results in high alpha and beta diversity and therefore the region is considered to be a key regional biodiversity hotspot (Boshoff 2005, Mucina and Rutherford 2006, Aiello-Lammens et al. 2017). Fire dynamics has been recognized as a key factor that strongly influences vegetation community structures and biome boundaries within the Baviaanskloof (Aiello-Lammens et al. 2017).

The Baviaanskloof valley as well as the tributary valley
where the BK-2-2 midden is located (Fig. 1) is dominated by
Baviaans Valley Thicket vegetation (sensu Mucina et al. 2006-
2018). This subtropical low, evergreen, closed-canopy vegeta-
tion type is characterised by succulent thicket taxa such as
*Euphorbia*, *Aloe*, *Crassula*, *Carissa* (Apocynaceae) and *Searsia*
(Anacardiaceae) species or *Portulacaria afra* (Didieraceae).
Nanophanerophytes are prevalent, representing a dispersedly
emergent element with *Pappea capensis*, *Dodonaea viscosa*
(Sapindaceae), *Boscia oleoides* (Capparidaceae), *Grewia
robusta* (Malvaceae), *Schotia afra* (Fabaceae) and *Diospyros
scabrida* (Ebenaceae) (Vlok and Euston-Brown 2002, Mucina
and Rutherford 2006). Shrubs such as *Agathosma puberula*
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Figure 1. (A) The location of the BK-2-2 site (white star) in relation to South Africa and the African continent. (B) The location of the BK-2-2 site (white star) within the aseasonal rainfall zone (rainfall zone contours derived from MJJAS precipitation values extracted from the Worldclim (2.1) dataset (Fick and Hijmans 2017)) and in relation to the modern South African biome boundaries (Mucina et al. 2006–2018) and the locations of published palaeoenvironmental records from the region: Erica Kuil (Manzano et al. 2023), Pearly Beach (Quick et al. 2021), Rietvlei-Still Bay (Quick et al. 2015), Seweweekspoort (Chase et al. 2013, 2017), Cango Cave (Talma and Vogel 1992), Eilandvlei (Kirsten et al. 2018, Quick et al. 2018, Wündsch et al. 2018), Bo Langvlei (du Plessis et al. 2020), Groenvlei (Martin 1968, Wündsch et al. 2016), Vankervelsvlei (Quick et al. 2016, Strobel et al. 2022), Nelson Bay Cave (Cohen and Tyson 1995) and Kamanassie River (Scott et al. 2021). (C) The location of the BK-2-2 midden site (white star) in relation to the current distribution of dominant vegetation types around the site (Mucina et al. 2006–2018). The area in (C) is represented by the black box in (B).
(Rutaceae), *Aspalathus setacea* (Fabaceae), *Polygala myrtifolia* (Polygalaceae) occur within the thicket vegetation while grasses are not prevalent within the valley (Vlok and Euston-Brown 2002). Afrotemperate forest pockets occur as small, isolated patches amidst the thicket vegetation and often within riparian zones/river kloofs, some of the most representative elements include *Afrocarpus falcatus* (Podocarpaceae), *Ficus sur* and *Celtis africana*. Riparian zones are also vegetated by *Nuxia floribunda* (Stilbaceae), *Salix* and *Morella serrata*. Alluvial vegetation can also include thorny elements such as *Vachellia karoo* and *V. natalitia* [Acacia-type pollen].

MTV is integrated by species associated with the Cape Floristic Region, predominantly occurring on the high-altitude plateaus and upper mountain slopes of the Baviaanskloof. Several vegetation units have been identified in the area by Mucina and Rutherford (2006). Baviaanskloof Shale Renosterveld is a Mediterranean-type fine-leaved shrubland found on a loamy, shale-derived plateau above the BK-2-2 site (Fig. 1). It is dominated by the fire-sensitive, fine-leaved *Dicerothamnus rhinoferotis* (Asteraceae) and various grasses (Poaceae). Kouga Grassy Sandstone Fynbos appears on sandstone-derived, skeletal soils. It develops as a low, open heathland with an undergrowth of grasses and sparse, emergent tall shrubs such as *Protea nitida*, *Aloe ferox*, *Aspalathus kougaensis* (Fabaceae) and *Dodonaea viscosa*, occupying a large area to the north of the site (Fig. 1, Mucina and Rutherford 2006). Kouga Sandstone Fynbos occurs on sandstone banded outcrops and their derived soils at higher altitudes (Fig. 1). It is characterised by an encroachment of tall, emergent shrubs including several *Protea* and *Leucadendron* species (Proteaceae) and other tall, fine leaved fire-prone shrubs including *Euryops virgineus* (Asteraceae), *Metalasia trivialis* (Asteraceae), *Passerina falcifolia* and the endemic Cupressaceae, *Widdringtonia schwarzii*. Typical fynbos elements organise into a moderately dense low shrub stratum and include species from the Proteaceae, Ericaceae, Rutaceae and Fabaceae families, accompanied by different species of *Anthospermum*, *Cliffortia* and *Stoebe*. Baviaanskloof Shale Renosterveld, Kouga Sandstone Fynbos and Kouga Grassy Sandstone Fynbos grade into each other within this region and constitute a broad xerophilous fynbos-renosterveld mosaic.

# Material and methods

## Archive extraction and sampling

The rock hyrax midden analysed for this study Baviaanskloof-2-2 (BK-2-2, 33.53°S, 23.76°E, 800 m a.s.l) was extracted from a northeast facing rock shelter located within a tributary valley cut into the southern flank of the Baviaanskloof (Chase et al. 2020, Fig. 1). The BK-2-2 midden was collected in 2010 and is described in Chase et al. (2020). A representative portion of the midden (186 mm in depth) was cut perpendicular to the stratigraphy using an angle grinder, and sections were cleaned using progressively

finer grades of sandpaper prior to subsampling. Pollen samples were cut from the midden section using a diamond dental saw. Samples for pollen analysis range in thickness from 4.63 to 13.96 mm, as a function of midden density and friability, incorporating an average of 420 years of accumulation in each sample.

## Chronological control

The radiocarbon age determinations for the BK-2-2 midden, together with the stable carbon and nitrogen isotope data, are presented and discussed in Chase et al. (2020). For this study, the radiocarbon ages were re-calibrated using the SHCal20 calibration curve (Hogg et al. 2020, supplied in the Supporting information). The age model was generated using the Bayesian Bacon ver. 3.1.0 R package (Blaauw and Christen 2011, Blaauw et al. 2021, refer to the Supporting information).

## Palynology and charcoal analysis

The extraction of palynomorphs from the BK-2-2 midden samples followed standard laboratory processing methods (Moore et al. 1991) together with specific adaptations for dense media separation outlined in Nakagawa et al. (1998). Samples were initially sieved using 150 µm sieves, then subjected to a 30% HCl treatment (to remove carbonates) and 10% KOH digestion (to disaggregate the samples and remove humic acids). Heavy liquid mineral separation (using ZnCl₂) was used to separate the pollen from the non-pollen matrix (Nakagawa et al. 1998). Samples were acetolysised and mounted in the aqueous mounting agent *Aquatex*. Absolute pollen concentrations were determined by means of the addition of *Lycopodium* spores to the samples prior to sieving and chemical processing (Stockmarr 1971).

Pollen counts of 300 grains per sample were carried out at 400× magnification. Non-pollen palynomorphs (NPPs) were counted but not included in the total pollen sum. Nelson Mandela University's online reference collection (https://pollen.mandela.ac.za) together with the atlas of Chevalier et al. (2021) was used for the identification of pollen taxa.

Pollen type nomenclature follows the seminal work of Louis Scott (Scott 1982), whereas botanical nomenclature, and systematics including taxa authors, omitted here for clarity of the text, follows Manning and Goldblatt (2012) and Bredenkamp (2019), where other taxonomical proposals derived from posterior taxonomical reviews have been followed, taxa authors are indicated. NPPs including coprophilous and non-coprophilous fungal spores were recorded and identified following the standard NPP nomenclature (Gelorini et al. 2011, van Geel et al. 2011, van Asperen et al. 2021).

The pollen and microcharcoal diagram was constructed in *Tilia* (ver. 3.0.1) and was divided into pollen assemblage zones based on a CONISS (constrained incremental sum of squares) cluster analysis (with square-root transformation) (Grimm 2011).
Microcharcoal particles were identified and counted on the same microscope slides that were analysed for their palynological content. Only particles that were black, opaque and angular were considered charcoal fragments, and were classified and counted according to two size categories based on the long axis of each fragment: 10–100 µm (representing the regional fire signal) and >100 µm (reflecting the local fire signal). Fragments smaller than 75 µm² (or ~ 10 µm long) were not counted due to the risk of false identification (Mooney and Tinner 2011). Absolute charcoal abundances were calculated in the same manner as pollen concentrations (Stockmarr 1971).

# Results

## Palynology and charcoal analysis

A total of 106 palynomorphs were identified from the 29 BK-2-2 samples, comprising of 96 pollen taxa and ten NPPs of which four are coprophilous fungal spores. Fig. 2 summarises the most significant and abundant taxa, while the full dataset is included in the Supporting information. Pollen preservation is generally good for the sequence except for samples from the base of the midden (from ~ 7400–6000 cal year BP). The average pollen concentration was 14 261 grains per gram of sample (maximum=33 357 grains g⁻¹, minimum=2627 grains g⁻¹).

The BK-2-2 pollen assemblage data reflects the mosaic nature of the vegetation within the Baviaanskloof. Thicket elements (e.g. *Aloe*, *Euphorbia*, *Searsia*, *Euclea*, *Olea* and Polygalaceae) together with more cosmopolitan succulent taxa (e.g. *Crassula* and Aizoaceae-type which includes *P. afra* 'Spekboom' a key thicket component) dominate the sequence. There is also the presence of *Podocarpus/Afrocarpus* a key Afrotemperate forest pollen indicator taxon and fynbos-renosterveld elements (mainly represented by *Passerina*, *Anthospermum*-type, *Stoebe*-type, Ericaceae, Thymelaeaceae and Brassicaceae as well as Cape thicket elements such as *Widdringtonia* likely *W. schwarzii* the willowmore cedar). Cosmopolitan taxa that are well represented throughout the sequence include Euphorbiaceae, Fabaceae and Asteraceae, the latter of which exhibits high percentages within the late Holocene.

The pollen data was separated into two statistically significant assemblage zones and four subzones, based on the results of the CONISS analysis (Fig. 2).

## Dominance of Mediterranean-type vegetation during the mid to late Holocene: Zone BK-2-A (ca 6000–3300 cal year BP)

The onset of the sequence, pollen assemblage sub-zone BK-2-A1 (ca 6000–5000 cal year BP), has the largest presence of MTV from the Cape Floristic Region (fynbos/renosterveld), with elevated percentages of *Anthospermum*-type, *Passerina*, *Stoebe*-type (which includes *D.*

*rhinocerotis*, the architect species of renosterveld), *Dodonaea* and Thymelaeaceae, with consistent, albeit low, percentages of Ericaceae. Subtropical thicket and Afrotemperate forest pollen representation are both significantly lower than in all other subzones. Asteraceae percentages are very low (below 2%), while monolete and trilete spores are highest for sequence within this subzone.

Low percentages of Asteraceae are sustained through subzone BK-2-A2 (ca 5000–3300 cal year BP), while the proportion of MTV is slightly lower within this subzone compared to BK-2-A1. Subtropical thicket percentages remain low while afrotemperate forest/mesic subtropical thicket elements are relatively high, especially around 4000–3600 cal year BP. Euphorbiaceae is found in relatively high abundances throughout this subzone and within the middle of this subzone, at ca 4600 cal year BP, Aizoaceae percentages peak. This is coeval with a depletion of monolete and trilete spores. This subzone is characterised by the most significant peak in both microcharcoal size classes for the sequence, with concentrations of 110 157 and 207 581 fragments/gram at the top of the zone (ca 3600–3300 cal year BP).

## Dominance of subtropical thicket during the late Holocene: zone BK-2-B (ca 3300–100 cal year BP)

Subzone BK-2-B1 (ca 3300–1200 cal year BP) is dominated by high percentages of subtropical thicket taxa with the first prominent appearances of Polygalaceae and *Searsia* and the presence of *Olea*, *Euphorbia*, *Euclea* and *Diospyros*, peaking from ca 2700–2400 cal year BP.

Aizoaceae – which includes the thicket species *P. afra* as its pollen is morphologically indistinguishable from Aizoaceae – is also present in high abundances, especially from ca 2200–1500 cal year BP. Asteraceae pollen percentages are relatively high for this subzone in comparison to the previous zones and exhibit the highest percentages for the sequence at ca 2400 cal year BP (12%) and ca 2000 cal year BP (19%). The overall MTV sum is lower than in BK-2-A2 (ca 6000–3300 cal year BP), however there are peaks in *Passerina* at ca 3000 cal year BP and *Scrophulariaceae*-type at ca 1200 cal year BP and a sustained presence of Brassicaceae. Parallel to the reduced microcharcoal is a reduction in both monolete and trilete spores.

The most recent subzone spanning between ca 1200 and 100 cal year BP (BK-2-B2) is characterised by the highest presence of thicket pollen documented for the sequence. Mediterranean-type elements are generally represented at low abundances with distinct reductions in Brassicaceae, *Passerina* and Thymelaeaceae. Zone BK-2-B2 is also distinguished from the rest of the sequence by the lowest proportions of Aizoaceae and by possible anthropogenic signals, including elevated proportions of coprophilous fungal spores (possibly indicating the presence of cattle) and the presence of the neophyte *Pinus* and Poaceae pollen grains larger than 35 µm (possibly indicating the presence of cereal cultivation).
<figure><img src="image_7.png" /><figcaption>Figure 2. Relative percentage pollen and microcharcoal diagram for Baviaanskloof 2-2 (BK-2-2). Taxa grouped according to ecological affinities and are plotted against interpolated age (cal year BP). Taxa that represent less than 2% for any given level are presented as presence dots, the full data set is presented in the Supporting information. Exaggeration curves are 2X, and zonation is based on the results of a constrained incremental sum of squares (CONISS) analysis.</figcaption></figure>
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Figure 3. A summary of the main trends within the Baviaanskloof 2-2 (BK-2-2) data including the sums of the relative percentages of the ecological groups: Mediterranean-type vegetation (fynbos/renosterveld) (I) and Subtropical thicket(G), Asteraceae pollen percentages (F), microcharcoal concentrations (H) and the δ¹³C (C) and δ¹⁵N (D) isotope data (Chase et al. 2020) compared with the palaeotemperature reconstruction from Cango Cave (E) (Talma and Vogel 1992), the δ¹⁵N record from the Seweweekspoort rock hyrax middens (A) (Chase et al. 2017) and the Afrotemperate forest pollen record from Eilandvlei (B) (Quick et al. 2018).
Discussion

Long-term ecological dynamics at the Mediterranean-
type vegetation/Subtropical boundary in the
Baviaanskloof

Mediterranean-type vegetation resilience from ca 7500 to
3300 cal year BP (Zone BK-2-A)

The onset of the BK-2-2 stable isotope record predates the start of the pollen sequence by ~ 1500 years as no pollen was preserved within the lowermost samples. δ¹⁵N values for this initial period are relatively high indicating decreased humidity (Chase et al. 2020, Fig. 4). This, together with generally colder temperatures inferred from the nearby Cango Cave palaeotemperature record (Talma and Vogel 1992, Fig. 4), would likely mean that conditions were similar to – or slightly cooler and more humid than – the initial portion of the pollen record (Zone BK-2-2-A, ca 6000–3300 cal year BP). This climatic context frames the development of a MTV, with the presence of *Erica*, *Stoebe*-type, *Dodonaea*, *Passerina* and other Thymelaeaceae resulting in the dominance of mesic fynbos and renosterveld communities, which probably formed a mosaic of shrublands and heathlands (Mucina and Rutherford 2006, Bergh et al. 2014, Fig. 3). Subtropical elements are very limited during this period and are only represented by *Euphorbia* and *Euclea* and the taller, more water demanding forest-margin *Diospyros* and *Pterocelastrus*.

Increasingly arid conditions from ca 6000 to 3300 cal year BP result in reorganisations within the still dominant fynbos-renosterveld mosaic with a greater presence of Brassicaceae pollen, likely ascribable to *Heliophila*, a species-rich Cape endemic genus associated with open, dry expressions of fynbos and renosterveld (Mucina and Rutherford 2006). The peaks in Brassicaceae pollen together with increases in the presence of geophytes (Liliaceae and Iridaceae) and decreases in Thymelaceae are consistent with a more open landscape as a result of aridification. Fire dynamics, evidenced by moderate microcharcoal concentrations, align well with the established ecological association between recurrent, small-scale fires and the dynamics of MTV such as fynbos (Cowling 1992, Aiello-Lammens et al. 2017, Fig. 3-4).

Subtropical thicket elements remain stable between ca 6000 and 3300 cal year BP, however, Aizoaceae peak at around 4000 cal year BP coinciding with warmer, more arid conditions as evidenced by the δ¹⁵N and δ¹³C values and the Cango Cave palaeotemperature reconstruction (Fig. 3). While MTV is still dominant during this period (primarily indicated by the peaks in Brassicaceae), the warmer and drier conditions result in an encroachment of succulent vegetation (Fig. 4).

It is reasonable that this encroachment could be associated with the development of dense stands of *P. afra* (Didieraceae; the pollen of which is indistinguishable from Aizoaceae), which today dominate the drier typologies of subtropical thickets (Vlok et al. 2003, Mills et al. 2005, Mills and Cowling 2006). The productivity of this species is unusually high for a semi-arid subtropical element. As pollen concentrations and

Aizoaceae percentages follow a similar trend throughout the sequence (Fig. 2), this could suggest that Aizoaceae prevalence may be taken as an indirect correlate of local vegetation density (Magri and Parra 2002).

The representation of the Cape floristic element reaches a maximum for the sequence from ~ 3300–3000 cal year BP, coinciding with the largest peak in microcharcoal amounts and concentrations (Fig. 2), aligning well with the established ecological associations between fire and fynbos (Cowling 1992, Aiello-Lammens et al. 2017). Environmental conditions underpinning this fire event (which we consider to either be a single mega-fire or multiple fires across the landscape) are generally colder and wetter (Fig. 3), suggesting that this fire intensification is controlled by fuel availability.

Post-fire subtropical thicket dominance from ca
3300 to 100 cal year BP (Zone BK-2-B)

The period from ca 3300–2000 cal year BP is characterised by substantial changes in the pollen record (Fig. 2), indicating that major shifts in vegetation composition occurred within the Baviaanskloof across this period. While the mosaic Cape/Subtropical ecotonal nature of the vegetation is still very much apparent, there is clear evidence of a shift in the dominant floristic elements after the fire event around 3300 cal year BP. The precise timing of this fire event (or series of events) is difficult to constrain in the microfossil record due to the sample thickness and thus age range (with minimum top and maximum bottom ages of 2700 and 3850 cal year BP). Based on the more highly-resolved stable isotope data we infer that the fire event occurs at ca 2800 cal year BP (Chase et al. 2020). After this event, subtropical thicket percentages increase rapidly and remain in high proportions until the end of the sequence, while the representation of the Cape Floristic elements decline. This major shift is framed by the generally warmer and drier conditions of the late Holocene (as indicated by the δ¹⁵N record and the Cango Cave temperature reconstructions, Fig. 3) which would have favoured thermophilous/relatively drought-adapted vegetation types.

From ca 2200 cal year BP, higher Aizoaceae percentages suggest the encroachment of dense *Portulacaria* thicket stands. It is likely that a complex structure developed with emerging nanophanerophytes such as *Diospyros*, *Euclea*, *Olea*, *Pterocelastrus* and the succulents *Aloe* and *Crassula obovata* (a densely flowering arborescent succulent (Vlok et al. 2003, Fig. 2). Asteraceae percentages follow subtropical thicket dynamics however, the specific or tribal ascription of the pollen grains is challenging. Typical subtropical lineages such as *Senecio* and *Cineraria* intermingle in this contact area with Cape endemic genera such as *Pteronia*, *Felicia*, or *Chrysocoma* in the Astereae with species both typical of transitional shrublands and are important in open dry thickets (Vlok et al. 2003, Mucina and Rutherford 2006). We have excluded them from the subtropical thicket sum, yet given the similar trends in these taxa, it is plausible that the Asteraceae sum could represent either some of the succulent thicket species
Vegetation
composition and structure

Fire impact

<figure><img src="image_9.png" /></figure>

Figure 4. Vegetation composition, structure, and fire impact through the mid-late Holocene at the Subtropical/Mediterranean type vegetation boundary in the Baviaanskloof region of South Africa, as inferred from the palynological and microcharcoal data derived from the Baviaanskloof 2-2 rock hyrax midden sequence.
in the Senecioneae (e.g. *Senecio*, *Othonna* or *Cineraria*) or any
of the unpalatable *Osteospermum* shrubs *O. moniliferum*, *O.
polygalyphyllum* (Vlok et al. 2003, Mucina and Rutherford
2006, Manning and Goldblatt 2012, Bredenkamp 2019).
Fire activity is very low during this period (Fig. 3–4), in
agreement with the development of a dense, succulent, non-
flammable subtropical vegetation (Fig. 4).

The Cape Floristic elements are less represented after
the fire event and likely assembled as an open formation
of low shrubs in the Thymelaeaceae (including *Passerina*),
which is consistent with the structure and composition of
some Cape MTV typologies (renosterveld) (Mucina and
Rutherford 2006, Bergh et al. 2014). This is supported by
the reduced presence of typical fynbos elements such as *Erica*
and Proteaceae. Nonetheless the scattered marginal occur-
rence of the almost fynbos exclusive Restionaceae might indi-
cate a mosaic of loosely assembled floristically transitional
Mediterranean shrublands/heathlands.

A reactivation of fire processes is detected at the bound-
ary between BK-2-B1 and BK-2-B2 subzones (ca 1200–1000
cal year BP) coinciding with the first prominent appearance
of coprophilous fungal spores (Fig. 3–4). From ca 1200
cal year BP until the top of the sequence at ca 100 cal year
BP (AD 1850) the subtropical elements remain dominant
whereas MTV recedes slightly, yet a common internal reor-
ganisation pattern is recorded across the subtropical and the
Mediterranean type ecosystems. A depletion in the Aizoaceae
pollen sum, potentially comprising of plants of high grazing
value (such as *P. afra*) (Du Toit 1995, Thompson et al. 2009),
is accompanied by an enrichment in resinous non-palatable
species (Du Toit 1995) both from the Mediterranean-type
Cape and Subtropical floristic elements. The increases in
Mediterranean non-palatable *Stoebe*-type, Scrophulariaceae,
*Anthospermum* and *Dodonaea* are mirrored by the increases
in the subtropical *Searsia*, *Dyospiros*, *Euclea*, *Olea*, and
*Pterocelastyllrus* and Polygalaceae, most of which are character-
ised by grazing defences such as resins or latex (Proksch et al.
1982, Nthambeleni 2008, Mashimbye 2019, Lacaille-
Dubois et al. 2020). A steady increase and overall maxima in
coprophilous fungi suggests that this functional homogenisa-
tion of the ecologically very distinct Mediterranean-type and
subtropical ecosystems is consistent with the intensification
of pastoral activities within the area in the last millennium
(Boshoff 2005, Hoare et al. 2006).

Multi-tiered hierarchical forcings control within-
biome dynamics but fire drives major ecological
turnover at the Mediterranean type – subtropical
ecosystem boundary

The forcing mechanisms responsible for the changes in
hydroclimate within the wider southern Cape region are a
result of complex interplays between the major elements of
the regional southern African circulation patterns: the south-
ern westerlies drive climatic variability at multi-millennial
timescales, while at shorter, multi-centennial to millennial
timescales, there are strong similarities between the BK-2-2

isotope data and records dominated by tropical influences
(Chase et al. 2020). This suggests that changes in rainfall sea-
sonality are not homogenous across the ARZ.

There is a strong correlation between the broad vegeta-
tion trends inferred from the BK-2-2 pollen record and the
Cango Cave palaeotemperature record (Fig. 3), implying
that coupled temperature and hydrological changes represent
a very important control on environmental change at this
Mediterranean-type/Subtropical ecosystem boundary.

At a regional scale, the closest pollen record to BK-2-2 is derived from an exposed alluvial deposit within the Kamanassie River (KMR), ~ 50 km west of BK-2-2 (the ‘KMR’ sequence, Scott et al. 2021, Fig. 1) which is largely consistent with our findings, showing increased Mediterranean-type elements present during the late Pleistocene and early Holocene, potentially also influenced by increased rainfall seasonality as a result of the dominance of the southern westerlies during this time (Chase et al. 2020), followed by a greater dominance of Subtropical taxa associated with greater contributions of summer rainfall during the mid-late Holocene. Except for the KMR sequence and the Erica Kuil pollen record (covering the last ~ 1000 years from the far western interior WRZ – ARZ boundary (Manzano et al. 2023), the rest of the records from the aseasonal rainfall zone are from the coastal lowlands (Martin 1968, Quick et al. 2015, 2016, 2018, du Plessis et al. 2020, Fig. 1). Due to their position on the coast, these records are subject to local atmospheric and oceanic influences. Differences between these records (such as the EV-13 record, Fig. 3) and BK-2-2 further emphasize the subregional nature of both climate and vegetation patterns across the southern Cape during the Holocene, and in particular at the Mediterranean type/Subtropical ecotone, with coastal areas potentially less susceptible of being impacted by long-term rainfall seasonality variations than the interior regions (Chase and Quick 2018, Quick 2019). At a biogeographical scale, this particular pattern is also observable nowadays. Subtropical vegetation is restricted to an ecological space broadly limited by frost and reliable annual year-round rainfall between 200 and 700 mm (occasionally 1000 mm), it becomes sparser towards the continental interior and the seasonal winter rainfall areas to the west (Vlok et al. 2003). Westwards in the southern Cape scattered pockets of subtropical flora marginally integrate in coastal communities within the MTV of the Cape Floristic element (known as strandveld).

At a landscape scale, subtropical thickets are typically asso-
ciated with richer soils than the Mediterranean-type shrub-
lands and heathlands of the Cape Floristic Region although
they can occupy any substratum if the climatic conditions are
adequate (Vlok et al. 2003, Bergh et al. 2014). The bound-
ary between the Cape MTV and other non-MTV ecosystems
is more likely to be controlled by climate rather than geol-
ogy. Therefore, changes in hydroclimate can be expected to
control the dynamics of Mediterranean type/Subtropical eco-
system boundaries at a landscape scale. Under drier, warmer
aseasonal conditions subtropical taxa can potentially displace
both fynbos and renosterveld, whereas, under enhanced
winter rainfall and colder conditions, renosterveld can be
expected to outcompete subtropical elements and take over
the space occupied by subtropical thickets. Yet the propor-
tions of Mediterranean-type and subtropical elements within
the BK-2-2 sequence are broadly stable despite changes in the
hydroclimate.

Indeed, MTV at the Baviaanskloof research site is resil-
ient to the ongoing regional aridification trend from ~ 5500
cal year BP. It is not until the abrupt fire intensification
phase around ca 2800 cal year BP that ecological turnover
is observed, with an expansion of subtropical thickets at the
expense of Mediterranean-type taxa.

The fire ecology of subtropical thickets is poorly under-
stood. Subtropical thickets are typically non-flammable,
integrated by species combining different post fire recovery
traits. This includes non-flammable succulents (Portulacaria,
included within Aizoaceae pollen sum, and Euphorbia), obli-
gate resprouters with emerging evergreen broadleaves (e.g.
Searsia, Maytenus, Diospyros), and obligate reseeder compo-
nents such as P. myrtifolia (Polygalaceae) or Osteospermum
moniliferum (included in Asteraceae HS, Fig. 2). The local
post-fire dynamics of the above-mentioned taxa, dominating
the pollen diagram under a scenario of higher vegetation den-
sity (indicated by higher pollen concentration) subsequent
to the major fire event/events – indicates a change of state
between a primarily MTV towards a dense, subtropical thicket
dominated environment. MTV resilience together with the
rapid recovery of subtropical taxa suggests that they represent
stable alternative ecosystem states determined by fire under
certain event-dependent scenarios, such as burning season or
underlying aridity. Seeder life histories are common in Cape
Floristic elements, and while fire adapted, post-fire recruit-
ment might be compromised by the lack of reliable winter
moisture in some Cape MTV (West et al. 2012). Rapid post-
fire regeneration and encroachment of subtropical broadleaf
evergreen resprouters and succulents excludes shade-intoler-
ant Mediterranean species, and the prevalence of succulents
and evergreens does not support a regular fire regime (Fig. 4).
This tips the system towards a closed canopy, fire-resistant
state that excludes fire-prone Cape Mediterranean species.

Conclusion

Global change and vegetation response at the
Mediterranean-type/subtropical boundary

Global change predictions for South African Mediterranean-
type ecosystems combine unreliable winter rainfall,
extreme climatic events and changes in rainfall season-
ality (Tadross et al. 2005, Hewitson and Crane 2006,
Altwegg et al. 2014). These are expected to result in major
reorganisations in community structure and potentially dis-
place fire regimes beyond their range of natural variability.
Biome boundaries are sensitive to spatiotemporal changes in
climate and disturbance because it is here that ecosystems are
at their limit (Gillson et al. 2020, Pausas and Bond 2020,
Manzano et al. 2023).

This study reinforces the idea that MTV may come to be
in disequilibrium with climate and that fire can transgress
vulnerability thresholds at the Mediterranean-type/subtropi-
cal boundary. Other Mediterranean-type climate regions are
adjacent to functionally analogous fire-resistant systems such
as the aseasonal/year-round rainfall forests of SW Europe and
California, the subtropical Australian vine thickets and rain-
forests and the Chilean Valdivian forests. In every case, the
Mediterranean-type/subtropical boundary harbours glob-
ally important shares of plant and animal biodiversity. In
South Africa, this boundary covers over 5800 km (Mucina
and Rutherford 2006), representing a contact zone between
climatic, biogeographical, ecological, cultural systems that
assemble into highly biodiverse and threatened landscapes.

Using multi-proxy palaeoecological evidence can pro-
vide opportunities for understanding resilience and vulner-
ability thresholds at ecologically meaningful timescales and
under different combinations of ecological and disturbance
conditions. A functional trait-based interpretation of the
reconstructed landscape histories can provide a means for
understanding future responses of these highly diverse eco-
systems under the current scenarios of climate change.

Acknowledgements – We would like to thank Prof. Richard Cowling for assisting with the assignment of the pollen taxa to their ecological groupings.

**Funding** – This study was funded by the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC Starting Grant “HYRAX,” grant agreement no. 258657 and by the National Research Foundation of South Africa African Origins Platform grant no: 136507. Research on palynotaxonomy of Asteraceae is funded through the 2021 Smuts Grant received by S.M. M.C. is supported by the German Federal Ministry of Education and Research (BMBF) with the Research for Sustainability initiative (FONA) through the PalMod Phase III project (grant no. FKZ: 01LP2308B).

Author contributions

**Lynne J. Quick:** Conceptualization (lead); Data curation (lead); Formal analysis (lead); Funding acquisition (lead); Investigation (lead); Methodology (lead); Project administration (lead); Visualization (lead); Writing – original draft (lead); Writing – review and editing (lead). **Brian M. Chase:** Conceptualization (equal); Funding acquisition (equal); Investigation (equal); Resources (equal); Writing – original draft (equal); Writing – review and editing (equal). **Manuel Chevalier:** Methodology (supporting); Software (equal); Writing – review and editing (equal). **B. Adriaan Grobler:** Methodology (supporting); Resources (supporting); Writing – review and editing (equal). **Saúl Manzano:** Conceptualization (equal); Methodology (equal); Visualization (equal); Writing – original draft (equal); Writing – review and editing (equal).

Transparent peer review

The peer review history for this article is available at
https://www.webofscience.com/api/gateway/wos/
peer-review/10.1111/ecog.
## Data availability statement

Data are available from the Neotoma Palaeoecology Database as a contribution to the African Pollen Database.: https://data.neotomadb.org/datasets/59360, https://apps.neotomadb.org/explorer/?datasetids=59360 (Quick et al. 2024).

## Supporting information

The Supporting information associated with this article is available with the online version.

## References

Aiello-Lammens, M. E., Slingsby, J. A., Merow, C., Mollmann, H. K., Euston-Brown, D., Jones, C. S. and Silander Jr, J. A. 2017. Processes of community assembly in an environmentally heterogeneous, high biodiversity region. – Ecography 40: 561–576.

Altwegg, R., West, A., Gillson, L. and Midgley, G. F. 2014. Impacts of climate change in the Greater Cape Floristic Region. – In: Allsopp, N., Colville, J. F. and Verboom, G. A. (eds), Ecology, Evolution, and Conservation of a Megadiverse Region. Oxford Univ. Press, pp. 299–320.

Bergh, N. G., Verboom, G. A., Rouget, M. and Cowling, R. M. 2014. Vegetation types of the Greater Cape Floristic Region. – In: Allsopp, N., Colville, J. F. and Verboom, G. A. (eds), Fynbos: ecology, evolution, and conservation of a megadiverse region. Oxford Univ. Press, pp. 1–25.

Blaauw, M. and Christen, J. A. 2011. Flexible paleoclimate age-depth models using an autoregressive gamma process. – Bayesian Anal. 6: 457–474.

Blaauw, M., Christen, J. A., Lopez, M. A. A., Vazquez, J. E., Belding, T., Theiler, J., Gough, B., Karney, C., Rcpp, L. and Blaauw, M. M. 2021. R Package ‘rbacon’. – https://cran.r-project.org/web/packages/rbacon/index.html.

Boshoff, A. F. 2005. The Baviaanskloof Mega-Reserve: an environmentally, socially and economically sustainable conservation and development initiative. – Nelson Mandela Univ.

Bredenkamp, C. L. 2019. A flora of the eastern cape province. Vol. 3. – South African National Biodiversity Institute.

Chase, B. M. and Meadows, M. E. 2007. Late Quaternary dynamics of southern Africa’s winter rainfall zone. – Earth Sci. Rev. 84: 103–138.

Chase, B. M. and Quick, L. J. 2018. Influence of Agulhas forcing of Holocene climate change in South Africa’s southern Cape. – Quat. Res. 90: 303–309.

Chase, B. M., Scott, L., Meadows, M. E., Gil-Romera, G., Boom, A., Carr, A. S., Reimer, P. J., Truc, L., Valsecchi, V. and Quick, L. J. 2012. Rock hyrax middens: a palaeoenvironmental archive for southern African drylands. – Quat. Sci. Rev. 56: 107–125.

Chase, B. M., Boom, A., Carr, A. S., Meadows, M. E. and Reimer, P. J. 2013. Holocene climate change in southernmost South Africa: rock hyrax middens record shifts in the southern westernlies. – Quat. Sci. Rev. 82: 199–205.

Chase, B. M., Chevalier, M., Boom, A. and Carr, A. S. 2017. The dynamic relationship between temperate and tropical circulation systems across South Africa since the Last Glacial Maximum. – Quat. Sci. Rev. 174: 54–62.

Chase, B. M., Boom, A., Carr, A. S., Quick, L. J. and Reimer, P. J. 2020. High-resolution record of Holocene climate change

dynamics from southern Africa’s temperate-tropical boundary, Baviaanskloof, South Africa. – Palaeogeogr. Palaeoclimatol. Palaeoecol. 539: 109518.

Chevalier, M., Chase, B. M., Quick, L. J. and Scott, L. 2021. An atlas of southern African pollen types and their climatic affinities, quaternary vegetation dynamics. – CRC Press, pp. 239–258.

Cockcroft, M. J., Wilkinson, M. J. and Tyson, P. D. 1987. The application of a present-day climatic model to the late quaternary in southern Africa. – Clim. Change 10: 161–181.

Cohen, A. L. and Tyson, P. D. 1995. Sea surface temperature fluctuations during the Holocene off the south coast of Africa: implications for terrestrial climate and rainfall. – Holocene 5: 304–312.

Cowling, R. M. 1992. The ecology of fynbos: nutrients, fire, and diversity. – Oxford Univ. Press.

du Plessis, N., Chase, B. M., Quick, L. J., Haberzettl, T., Kasper, T. and Meadows, M. E. 2020. Vegetation and climate change during the medieval climate anomaly and the little ice age on the southern Cape Coast of South Africa: pollen evidence from Bo Langvlei. – Holocene 30: 0959683620950444.

Du Toit, P. C. V. 1995. The grazing index method of range condition assessment. – Afr. J. Range Forage Sci. 12: 61–67.

Euston-Brown, D. and Kruger, M. 2023. Plants of the Baviaanskloof. – Struik Nature.

Fick, S. E. and Hijmans, R. J. 2017. WorldClim 2: new 1-km spatial resolution climate surfaces for global land areas. – Int. J. Climatol. 37: 4302–4315.

Gelorini, V., Verbeken, A., van Geel, B., Cocquyt, C. and Verschuren, D. 2011. Modern non-pollen palynomorphs from East African lake sediments. – Rev. Palaeobot. Palynol. 164: 143–173.

Gillson, L., MacPherson, A. J. and Hoffman, M. T. 2020. Contrasting mechanisms of resilience at mesic and semi-arid boundaries of fynbos, a mega-diverse heathland of South Africa. – Ecol. Complexity 42: 100827.

Gillson, L. and Marchant, R. 2014. From myopia to clarity: sharpening the focus of ecosystem management through the lens of palaeoecology. – Trends Ecol. Evol. 29: 317–325.

Grimm, E. 2011. Tilia software v. 1.7.16. – Illinois State Museum.

Hewitson, B. and Crane, R. 2006. Consensus between GCM climate change projections with empirical downscaling: precipitation downscaling over South Africa. – Int. J. Climatol. A J. R. Meteorol. Soc. 26: 1315–1337.

Hoare, D. B., Mucina, L., Rutherford, M. C., Vlok, J. H., Euston-Brown, D. I., Palmer, A. R., Powrie, L. W., Lechmere-Oertel, R. G., Proches, S. and Dold, A. P. 2006. Albany thicket biome. The vegetation of South Africa, Lesotho and Swaziland. – Strelitzia 19: 541–567.

Hogg, A. G., Heaton, T. J., Hua, Q., Palmer, J. G., Turney, C. S., Southon, J., Bayliss, A., Blackwell, P. G., Boswijk, G. and Ramsey, C. B. 2020. SHCal20 Southern Hemisphere calibration, 0–55,000 years cal BP. – Radiocarbon 62: 759–778.

Kirsten, K. L., Haberzettl, T., Wündsch, M., Frenzel, P., Meschner, S., Smit, A. J., Quick, L. J., Mäusbacher, R. and Meadows, M. E. 2018. A multiproxy study of the ocean-atmospheric forcing and the impact of sea-level changes on the southern Cape coast, South Africa during the Holocene. – Palaeogeogr. Palaeoclimatol. Palaeoecol. 496: 282–291.

Lacaille-Dubois, M.-A., Delaude, C. and Mitaine-Offer, A.-C. 2020. A review on the phytopharmacological studies of the genus *Polygala*. – J. Ethnopharmacol. 249: 112417.
Magri, D. and Parra, I. 2002. Late Quaternary western Mediterranean pollen records and African winds. - Earth Planet. Sci. Lett. 200: 401-408.

Manning, J. and Goldblatt, P. 2012. Plants of the greater Cape floristic region. 1: the core Cape flora. Strelitzia 29. - S. Afr. Natl Biodiversity Inst.

Manzano, S., Quick, L. J., Chase, B. M., Hoffman, M. T. and Gillson, L. 2023. Long-term vegetation response to rainfall seasonality and fire in the heathlands and shrublands of the Cape Floristic Region (SW South Africa). - Global Planet. Change 220: 104014.

Martin, A. R. H. 1968. Pollen analysis of Groenvlei lake sediments, Knysna (South Africa). - Rev. Palaeobot. Palynol. 7: 107-144.

Mashimbye, N. N. 2019. Ethnobotanical uses, anatomical features, phytochemical properties, antimicrobial activity, and cytotoxicity of the Sotho medicinal plant Searsia erosa (Anacardiaceae). - Univ. of Johannesburg.

Mills, A., Cowling, R., Fey, M., Kerley, G., Donaldson, J., Lechmere-Oertel, R., Sigwela, A., Skowno, A. and Rundel, P. 2005. Effects of goat pastoralism on ecosystem carbon storage in semiarid thicket, Eastern Cape, South Africa. - Austral Ecol. 30: 797-804.

Mills, A. J. and Cowling, R. M. 2006. Rate of carbon sequestration at two thicket restoration sites in the Eastern Cape, South Africa. - Restor. Ecol. 14: 38-49.

Mooney, S. D. and Tinner, W. 2011. The analysis of charcoal in peat and organic sediments. - Mires Peat 7: 1-18.

Moore, P. D., Webb, J. A. and Collinson, M. E. 1991. Pollen analysis, 2nd edn. - Blackwell Scientific Publications.

Mucina, L. and Rutherford, M. C. 2006. The vegetation of South Africa, Lesotho and Swaziland, Strelitzia. - S. Afr. Natl Biodiversity Inst.

Mucina, L., Rutherford, M. C. and Powrie, L. W. (eds). 2006-2018. South African national Biodiversity Institute. The vegetation map of South Africa, Lesotho and Swaziland. - S. Afr. Natl Biodiversity Inst.

Myers, N., Mittermeier, R. A., Mittermeier, C. G., da Fonseca, G. A. B. and Kent, J. 2000. Biodiversity hotspots for conservation priorities. - Nature 403: 853-858.

Nakagawa, T., Brugiapaglia, E., Digerfeldt, G., Reille, M., De Beaulieu, J.-L. and Yasuda, Y. 1998. Dense media separation as a more efficient pollen extraction method for use with organic sediment/deposit samples: comparison with the conventional method. - Boreas 27: 15-24.

Nthambeleni, R. 2008. Isolation and characterization of cytotoxic compounds from *Anthosperum hispidulum* and *Eriophthalmus tenuifolius*. - Univ. of Kwazulu-Natal.

Pausas, J. G. and Bond, W. J. 2020. Alternative biome states in terrestrial ecosystems. - Trends Plant Sci. 25: 250-263.

Proksch, P., Proksch, M., Rundel, P. W. and Rodriguez, E. 1982. Ecological significance of the chemistry of the leaf resin of *Elytropappus rhinocerotis*. - Biochem. Syst. Ecol. 10: 49-53.

Quick, L. J. 2019. Palaeoenvironments of the Cape Floristic Region: exploring subregional variability in southern Cape palaeoclimates. - National Research Foundation (NRF) of South Africa.

Quick, L. J., Carr, A. S., Meadows, M. E., Boom, A., Bateman, M. D., Roberts, D. L., Reimer, P. J. and Chase, B. M. 2015. A Late Pleistocene-Holocene multi-proxy record of palaeoenvironmental change from Still Bay, southern Cape Coast, South Africa. - J. Quat. Sci. 30: 870-885.

Quick, L. J., Chase, B. M., Wündsch, M., Kirsten, K. L., Chevalier, M., Mäusbacher, R., Meadows, M. E. and Haberzettl, T. 2018. A high-resolution record of Holocene climate and vegetation dynamics from the southern Cape Coast of South Africa: pollen and microcharcoal evidence from Eilandvlei. - J. Quat. Sci. 33: 487-500.

Quick, L. J., Chase, B. M., Carr, A. S., Chevalier, M., Grobler, B. A. and Meadows, M. E. 2022. A 25,000 year record of climate and vegetation change from the southwestern Cape Coast, South Africa. - Quat. Res. 105: 82-99.

Quick, L. J., Meadows, M. E., Bateman, M. D., Kirsten, K. L., Mäusbacher, R., Haberzettl, T. and Chase, B. M. 2016. Vegetation and climate dynamics during the last glacial period in the fynbos-aftrotemperate forest ecotone, southern Cape, South Africa. - Quat. Int. 404: 136-149.

Quick, L. J., Chase, B. M., Chevalier, M., Adriaan Grobler, B. and Manzano, S. 2024. Data from: Fire drives major Holocene vegetation shifts between subtropical and Mediterranean-type ecosystems: a case study from a Biodiversity Hotspot in South Africa. - Neotoma Paleoecology Database, https://data.neotomadb.org/59360.

Scott, L. 1982. Late Quaternary fossil pollen grains from the Transvaal, South Africa. - Rev. Palaeobot. Palynol. 36: 241-278.

Scott, L., Manzano, S., Carr, A. S., Cordova, C., Ochando, J., Bateman, M. D. and Carrión, J. S. 2021. A 14000 year multi-proxy alluvial record of ecotone changes in a Fynbos-Succulent Karoo transition in South Africa. - Palaeogeogr. Palaeoclimatol. Palaeoecol. 569: 110331.

Steffen, W., Rockström, J., Richardson, K., Lenton, T. M., Folke, C., Liverman, D., Summerhayes, C. P., Barnosky, A. D., Cornell, S. E. and Crucifix, M. 2018. Trajectories of the earth system in the Anthropocene. - Proc. Natl Acad. Sci. USA 115: 8252-8259.

Stockmarr, J. 1971. Tablets with spores used in absolute pollen analysis. - Pollen Spores 13: 615-621.

Strobel, P., Bliedtner, M., Carr, A. S., Struck, J., du Plessis, N., Glaser, B., Meadows, M. E., Quick, L. J., Zech, M., Zech, R. and Haberzettl, T. 2022. Reconstructing Late Quaternary precipitation and its source on the southern Cape Coast of South Africa: a multi-proxy paleoenvironmental record from Vankervelsvlei. - Quat. Sci. Rev. 284: 107467.

Tadross, M., Jack, C. and Hewitson, B. 2005. On RCM-based projections of change in southern African summer climate. - Geophys. Res. Lett. 32: L23713.

Talma, A. S. and Vogel, J. C. 1992. Late Quaternary paleotemperatures derived from a speleothem from Cango Caves, Cape Province, South Africa. - Quat. Res. 37: 203-213.

Thompson, M., Vlok, J., Rouget, M., Hoffman, M., Balmford, A. and Cowling, R. 2009. Mapping grazing-induced degradation in a semi-arid environment: a rapid and cost effective approach for assessment and monitoring. - Environ. Manage. 43: 585-596.

van Asperen, E. N., Perrotti, A. and Baker, A. 2021. Coprophilous fungal spores: non-pollen palynomorphs for the study of past megaherbivores. - In: Marret, F., O'Keefe, J., Osterloff, P., Pound, M. and Shumilovskikh, L. (eds), Coprophilous fungal spores: non-pollen palynomorphs for the study of past megaherbivores. Geological Society of London.

van Geel, B., Gelorini, V., Lyaruu, A., Aptroot, A., Rucina, S., Marchant, R., Damsté, J. S. S. and Verschuren, D. 2011. Diversity and ecology of tropical African fungal spores from a 25,000-year palaeoenvironmental record in southeastern Kenya. - Rev. Palaeobot. Palynol. 164: 174-190.
van Zinderen Bakker, E. M. 1976. The evolution of late quaternary paleoclimates of Southern Africa. – Palaeoecol. Afr. 9: 160–202.

Vlok, J. and Euston-Brown, D. 2002. Subtropical thicket ecosystem planning project (STEP). – Biological Survey Report (Plants and Birds). Terrestrial Ecology Research Unit Report.

Vlok, J., Euston-Brown, D. and Cowling, R. 2003. Acocks' Valley Bushveld 50 years on: new perspectives on the delimitation, characterisation and origin of subtropical thicket vegetation. – S. Afr. J. Bot. 69: 27–51.

West, A. G., Dawson, T., February, E., Midgley, G., Bond, W. and Aston, T. 2012. Diverse functional responses to drought in a Mediterranean-type shrubland in South Africa. – New Phytol. 195: 396–407.

Wündsch, M., Haberzettl, T., Cawthra, H. C., Kirsten, K. L., Quick, L. J., Zabel, M., Frenzel, P., Hahn, A., Baade, J., Daut, G., Kasper, T., Meadows, M. E. and Mäusbacher, R. 2018. Holocene environmental change along the southern Cape Coast of South Africa – insights from the Eilandvlei sediment record spanning the last 8.9 kyr. – Global. Planet. Change 163: 51–66.

Wündsch, M., Haberzettl, T., Kirsten, K. L., Kasper, T., Zabel, M., Dietze, E., Baade, J., Daut, G., Meschner, S., Meadows, M. E. and Mäusbacher, R. 2016. Sea level and climate change at the southern Cape Coast, South Africa, during the past 4.2 kyr. – Palaeogeogr. Palaeoclimatol. Palaeoecol. 446: 295–307.