To the best of our knowledge at this time, above ground visibility of plant foliage is the most reliable determinant that a human forager could positively identify and extract the underground resource. The ultimate goal is to combine these observations with studies of nutrition, abundance estimates and return rates, so as to contribute to the resourcescape for a paleoscape model for the Cape south coast Marean et al. The study area is situated in the coastal plain between the Breede and Gouritz rivers on the Cape south coast Fig.
The rainfall regime shows little seasonality and rain may fall at any time of the year although slight rainfall peaks are observed in March—April and with more pronounced peaks during August and October—November Engelbrecht et al. The overall climate of the study area is semi-arid to sub-humid with annual rainfall ranging from to mm. The three summer months Dec—Feb are the most stressful for plant growth, owing to generally lower rainfall and persistently higher temperatures.
A The location and major vegetation types of the study region and the plot localities [1: Renosterveld purple ; 2: Limestone Fynbos green ; 3: Sand Fynbos yellow ; and 4: Strandveld orange; restricted to the coastal margin; see Table S1 for further plot details ].
C Photos taken within the four plots in the different vegetation types. In addition, near the coastal margin aeolian sands of marine origin mantle the geology and this varies in pH with age; younger sands are alkaline and older sands are leached and acidic Rebelo et al. Shale- and mudstone-derived soils are moderately fertile, while those associated with leached sands are infertile. The vegetation types chosen for this study are representative of dissected coastal margin of the southern CFR, namely Fynbos two types , Renosterveld and Subtropical Thicket Rebelo et al.
This study monitored the phenological phase of edible plants—periodic life cycle events—growing in single plots located in Renosterveld, Sand Fynbos, Limestone Fynbos, and Strandveld a form of Subtropical Thicket. Renosterveld occurs on the relatively fertile and fine-grained soils derived from shales and mudstones, and is a fire-prone grassy shrubland often dominated by Elytropappus rhinocerotis renosterbos.
Sand Fynbos occurs on infertile acid soils and is a fire-prone heath-like shrubland, characterised by the presence of Restionaceae and Proteaceae. Limestone-derived soils support Limestone Fynbos, a highly endemic-rich vegetation type Willis et al. Marine sands are associated with Subtropical thicket, either in its solid form or as thicket clumps in a matrix of Fynbos.
This vegetation is colloquially known as Strandveld. Plant compositional change, or beta diversity, between these edaphically differentiated vegetation types is extremely high; consequently few species are shared among these four vegetation types and regional-scale plant richness is very high Cowling, The monitoring period was from May until April The effects of the previously dry year were still evident when monitoring started.
Above average rainfall was experienced over the two years of monitoring see Fig. S1 in Supplementary Materials for climate diagrams and Fig.
S2 for spatial relation of weather stations to survey plots. Monitoring plots were located in representative areas of each of the major vegetation types one plot per vegetation type described above: Renosterveld, Sand Fynbos, Limestone Fynbos, and Strandveld Fig. These plots were located within protected areas and were considered to be in a pristine condition. Further biophysical data for the plots are provided in the Supplementary Materials Table S1.
Monitoring consisted of surveying each plot every six weeks over a two-year period by one of the authors JC De Vynck , who is a trained field botanist familiar with the vegetation in this landscape. Along each transect, the following were counted: 1 individuals of species bearing Underground Storage Organs USOs which would be apparent to a forager i.
We included as edible any USOs that required cooking in order to render them edible e. As stated above, availability of edible carbohydrates was based on direct or indirect visibility of the resource.
For example, USOs in their dormant phase are not visible aboveground and can therefore not be procured by foragers. However, visible phases of USOs include any above indicator of their presence, such as green leaves, flowers or dry wilted leaves. The nutritional content may vary through these phases, but is not the focus of this study. The majority of species with aboveground carbohydrates e.
For each plot, the number of visible, and hence available, species with edible carbohydrates over time was determined; this was calculated as the number of individuals observed in a given survey that would provide access to edible carbohydrates divided by the maximum number of individuals observed across all surveys for a given species within a plot.
The number of species with edible carbohydrate considered available in each plot through time was calculated. All analyses were conducted in R version 2. Within the four 3. Of these, 33 species were geophytes with edible Underground Storage Organs USOs and 21 species had aboveground edible carbohydrates Table 1 ; see Tables S3 and S4 in Supplementary Materials for full species list per type.
Note that some species had more than one edible part. Richness of edible species varied across the vegetation types Table 1 : Limestone Fynbos had the richest flora, followed by Strandveld, Renosterveld and lastly, Sand Fynbos.
Summary of edible species in 3. Species varied in the length of time they were available through the year Fig. Species with USOs were available for longer periods of the year relative to those with edible aboveground carbohydrates. The availability of USO species differed across vegetation types and between survey years Fig.
Nonetheless, the number of available USO species was highest for a six-month period from winter to early summer Jul—Dec across all vegetation types. The number of species with available edible aboveground carbohydrates also varied across vegetation types and sample years.
Species richness peaked in spring Sep—Nov for all vegetation types; relatively high availability extended into summer Dec—Feb but autumn and early winter were lean months for harvesting aboveground carbohydrates in all vegetation types, especially Renosterveld and Sand Fynbos.
The presence of two Carpobrotus species, which bear ripe fruits during the drier months, was a key factor for the extension of aboveground availability period in Limestone Fynbos. A breakdown of the number of months in which different plant species with edible carbohydrates are visible through the year separated into A Underground Storage Organs USOs and B aboveground carbohydrates e.
Underground storage organs are geophytes that have tubers, corms, bulbs or rhizomes, while above-ground carbohydrates includes species with edible fruit, seed pods, seeds, leaves or inflorescences. The number of new species observed since the previous survey is shown in each circle; this provides an indication of species turnover. Twelve of these were USOs and Limestone Fynbos supported the most species 16 with available carbohydrates present at this time.
The diversity and abundance of edible plants, especially USOs, along the Cape coast, together with a rich source of both marine and terrestrial based protein, has been hypothesised to be key components facilitating the persistence of Middle Stone Age MSA people in the region during glacial phases when other African regions may have been resource poor Marean, However, very little research has been conducted on the potential availability of food plants to hunter-gatherers on the Cape south coast to corroborate this hypothesis.
In the same study area, Singels et al. Also, these USO hotspots were found within all vegetation types. Here we address the temporal availability of belowground i. USOs and aboveground sources of carbohydrates across the four principal vegetation types of the Cape south coast. We use this to speculate on the importance of carbohydrates as fallback foods for coastal hunter-gatherers, and what role this may have played in the emergence of cognitively modern people in the region Marean, The number of species with edible carbohydrate resources that are visible and available to foragers was highest between winter and early summer in the study area.
This is consistent with the dominant cool-season phenology of plants in the Cape Floristic Region Pierce, This six-month period provides a diversity of USOs associated with corms belonging to petaloid geophytes, mostly members of the Iridaceae e. Babiana, Freesia, Gladiolus, Watsonia. These species provide relatively large 10— g starch-rich and low-fibre food parcels that are inexpensive to harvest Parkington, ; Deacon, ; Singels et al. De Vynck, personal observations, Also available during the cooler and mostly wetter months are fruits borne largely by Subtropical thicket species e.
Carissa, Diospyros, Olea, Searsia as well as leaf crops Trachyandra spp. There are currently no data on the biomass, nutritional value and foraging returns for aboveground sources of carbohydrates in the Cape Floristic Region.
Fruit loads of mature thicket shrubs and trees range from tens of thousands of fruits per plant for Sideroxylon inerme fruit diameter 10 mm and Searsia spp 3 mm to fewer than fruits for Euclea racemosa 7 mm , Cassine tetragona 8 mm and Osyris compressa 20 mm Cowling et al.
Mat-forming Carpobrotus species may bear several tens of large 35 mm diameter fruits J. Late summer to early autumn periods have considerably fewer available edible species than in the other times of the year.
This is a period when all traces of leaves and inflorescences of the dominant deciduous geophyte component have disappeared Deacon, However, even during this relatively warm and dry period, we recorded some 25 available species across the four vegetation types Table 2.
These include USOs such as hysteranthous, autumn-flowering Gladiolus cormous and Pelargonium tuberous spp, the corms of evergreen Watsonia spp. Also apparent are the fruits Carpobrotus spp, the fruits of many thicket shrubs and trees, and the leaf crop, Tetragonia decumbens. Pelargonium spp. Overall, the plant-based carbohydrate resources available to Stone Age foragers of the Cape south coast, especially USOs belonging to the Iridaceae Deacon, ; Deacon, , are likely to have comprised a reliable and nutritious source of calories over most of the year.
In an assessment of foraging potential of six USO species growing in our study area, Singels et al. The juxtaposition within a 10 km foraging radius of four major vegetation types, belonging to three regional biomes Fynbos, Renosterveld and Subtropical Thicket; Bergh et al.
While the Limestone Fynbos and Strandveld—the two vegetation types closest to the coast—are likely to have offered the best foraging returns for much of the year, Renosterveld provides an abundance of Iridaceae corms in the spring and Sand Fynbos harbours evergreen Watsonia spp.
Ethnographic evidence suggest that the harvesting of Iridaceae corms uintjies in spring was an important event for the San of the Cape west coast Van Vuuren, Given the temporal and spatial availability of edible plant species in the Cape, we argue that is highly likely that USOs, fruit, seedpods, seeds, inflorescences and leaf crops were harvested as fallback foods by Stone Age people living in this region.
However, these resources were not always available to harvesters and hunters, and the contraction and expansion of the Agulhas Plain ecosystem and its ungulate communities must have been a major driver of changing foraging patterns on the south coast Marean et al.
It has been hypothesized that the mammal fauna formed a migratory community that moved west during the winter rains and east to intercept the summer rains. Thus, the local abundance of many of the larger ungulates may have plummeted during the winter months when populations migrated west to graze winter-growing grasses of the west coast.
Marine invertebrates, harvested from the intertidal, comprised the most reliable and accessible source of protein for hunter-gatherers living on the Cape south coast Marean, Late Stone Age sites suggest an increase in the intensity of intertidal foraging Marean et al. Using experienced foragers of Khoe-San descent, De Vynck et al. However, owing to tidal constraints, and the fierce sea conditions experienced there, harvesting was only possible for 10 days a month, for 2—3 hours on each day; lowest returns were recorded in winter and spring—a time of strong winds and high seas—and highest returns in summer and autumn, when sea conditions were calmer De Vynck et al.
Consequently, there would have been periods of various lengths—ranging from days to weeks—when hunter-gatherers depended on, or fell back upon carbohydrates for sustenance. As pointed out above, the winter and early spring months likely coincided with a scarcity of protein but an abundance of carbohydrates.
The persistently warm Agulhas Current reduced the regional impact of glacial cooling substantially Negre et al. Marean has hypothesised that during strong glacial environments, such as those experienced in MIS6, the Cape south coast provided a unique juxtaposition of resources important for hominin persistence, namely a diverse USO flora and a rich and productive marine ecosystem. The cognitive challenges of exploiting marine resources e.
Similarly, the ability to recognise which and when vegetation types are most productive for carbohydrates, identifying hotspots of productivity and distinguishing between edible and toxic USOs, must have been challenging Deacon, Here we have established the temporal availability of plant species with edible carbohydrates across four dominant vegetation types along the south coast. Much additional research must be done to evaluate more comprehensively the role of above- and belowground carbohydrates in the ecology and evolution of the human lineage in the Cape Floristic Region and elsewhere.
Work is currently underway to establish the return rates of carbohydrate resources harvested by contemporary subjects of Khoe-San descent, in the different vegetation types and in different seasons; and on the rates of depletion of resources in successively harvested areas. This needs to be complemented with data on the nutritional value of the consumed parts of the species selected.
Ultimately, we aim to use these data to populate the carbohydrate resourcescape in an agent-based model aimed at predicting the effects of spatial and temporal variability—governed by changes in climate and the resource base over the seasonal cycle as well as the glacial-interglacial cycle of the Pleistocene—on the population size and structure, mobility, social organization, territoriality, and technology of Cape hunter-gatherers Marean et al.
The raw data are six-weekly counts, over two years, of edible plants with Underground Storage Organs and aboveground edibles. These surveys were performed in predesignated 3. An index of all supplementary tables and figures. Phenological phase synchronicity is explained in detail and the methods which were employed in creating Fig.
References for the phenological phase synchronicity description. Phenology diagrams for plant species with Underground Storage Organs USOs and for fruiting plant species aboveground carbohydrate resources of the four primary vegetation types of the south Cape lowlands to coastal margin.
Total species list of USOs and fruiting species aboveground carbohydrate resources and their acronyms used in Fig. S3 encountered in the phenology survey of plots within four vegetation types of the southern Cape lowlands to coastal margin. Species list of USOs and fruiting species aboveground carbohydrate resources , and their acronyms, encountered in the phenology survey list of plots within four dominant vegetation types in the southern Cape lowlands to coastal margin. Acronyms relate to those used in Fig.
Climate diagrams showing temperature and rainfall patterns for the study sites during the survey period May —April Temperature and rainfall axes and shading follow Walter-Lieth conventions. Mean values of temperature and rainfall for the period are shown in parentheses.
The positions of weather stations relative to survey plots are shown in Fig. Locations of the vegetation survey plots and the weather stations shown in Fig. A hierarchical classification to establish phenological phase synchronicity specifically availability of edible carbohydrates among plant species from four different vegetation types along the Cape south coast South Africa.
The phenological phase plots show the relative proportion of individuals per species with visible edible carbohydrate through the sampling period within each cluster. The proportion of species within each phenological phase cluster per carbohydrate type i.
USO or aboveground and vegetation type are also shown. Species abbreviations are Tables S3 and S4. See Supplementary Methods for full explanation of the methods used to generate this figure. We also thank the Hessequa Municipality, and in particular Hendrik Visser, for their help and support.
The authors are also grateful for the climate data supplied by South African Weather Service. Peter Henzi and an anonymous reviewer provided valuable comments that improved the manuscript. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests Richard M. Cowling is an Academic Editor for PeerJ. The opinions expressed in this publication are those of the author s and do not necessarily reflect the views of the John Templeton Foundation. Author Contributions Jan C. Richard M. Alastair J. Curtis W. Marean wrote the paper, reviewed drafts of the paper. Data Deposition The following information was supplied regarding data availability:. The raw data was supplied as Supplemental Dataset files. National Center for Biotechnology Information , U.
Journal List PeerJ v. Published online Feb Jan C. De Vynck , 1 Richard M. Cowling , 1 Alastair J. Potts , 1 and Curtis W. Marean 1, 2. De Vynck. Author information Article notes Copyright and License information Disclaimer. Corresponding author.
De Vynck: az. Received Sep 15; Accepted Jan This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. This article has been cited by other articles in PMC. Meta data for raw data file. Supplemental Information 2: Raw data collected six-weekly over two years in the four primary vegetation types, southern Cape, South Africa.
Supplemental Information 3: Supplementary Material Methods. Supplemental Information 4: Biophysical information. Biophysical information for the four study sites. Supplemental Information 5: Phenology diagrams. Supplemental Information 6: Total species list. Supplemental Information 7: Total species list per vegetation type.
Supplemental Information 8: Climate diagrams. Supplemental Information 9: Climate map. Supplemental Information Phenological phase synchronicity. Methods Study area The study area is situated in the coastal plain between the Breede and Gouritz rivers on the Cape south coast Fig. Open in a separate window. Figure 1. Data collection The monitoring period was from May until April Data analysis For each plot, the number of visible, and hence available, species with edible carbohydrates over time was determined; this was calculated as the number of individuals observed in a given survey that would provide access to edible carbohydrates divided by the maximum number of individuals observed across all surveys for a given species within a plot.
Results Within the four 3. Table 1 Summary of edible species in 3. Figure 2. Figure 3. The seasonal availability of edible species visible to a human forager in four vegetation types dominant along the Cape south coast. Supplemental Information Supplemental Information 1 Meta data. Click here for additional data file.
Supplemental Information 2 Raw data collected six-weekly over two years in the four primary vegetation types, southern Cape, South Africa. Supplemental Information 3 Supplementary Material Methods.
Supplemental Information 4 Biophysical information. Supplemental Information 5 Phenology diagrams. Supplemental Information 6 Total species list. Supplemental Information 7 Total species list per vegetation type. Supplemental Information 8 Climate diagrams. Supplemental Information 9 Climate map. Supplemental Information 10 Phenological phase synchronicity. Soil nutrient content, above-ground biomass and litter in a semi-arid shrubland, South Africa. Bar-Matthews et al. A high resolution and continuous isotopic speleothem record of paleoclimate and paleoenvironment from 90 to 53 ka from Pinnacle Point on the south coast of South Africa.
Quaternary Science Reviews. Basell Basell LS. Middle Stone Age MSA site distributions in eastern Africa and their relationship to quaternary environmental change, refugia and the evolution of Homo sapiens.
Bergh et al. Vegetation types of the Greater Cape Floristic Region. Oxford: Oxford University Press; Sex differences in food preferences of hadza hunter-gatherers. Evolutionary Psychology. Human Ecology. Bliege Bird et al. Proceedings of the National Academy of Sciences. Cawthra et al. Submerged shorelines and landscape features offshore of Mossel Bay, South Africa. Fynbos species include rooibos, honeybush, buchu, snow bush, rhino bush, cancer bush and pelargoniums.
See the schedule and book online Nice to know: You can visit the medicinal garden which showcases indigenous plants used in traditional healing. In her workshop celebrating spring, you can learn to make flower crowns and learn about their history, and make wildflower tea and cakes.
Start by taking part in an edible flower- and foliage-picking session in the gardens. Head back to the cabin for floral arrangements, a medicinal flower talk, botanical bubbly, cocktails and snacks. Check with an expert if you are unsure. The pretty flowers can be used as a floral garnish for drinks, desserts, baked goods, salads or in ice.
The lemony-tasting leaves and stems can go in stews, salads or sandwiches in small amounts. Suggested by Carly. Calendula calendula officinalis : This is an easy-to-grow winter annual in the Western Cape that will flower throughout spring and into early summer. Snow bush Eriocephalus africanus : This highly aromatic type of fynbos has a wild-rosemary flavour.
Mix natural sea salt with dried snow bush to make a seasoning salt that complements all roasted food flavours. Also good in yoghurt-style accompaniments like tzatziki. Suggested by Giselle. Cancer bush Lessertia frutescens : This type of fynbos is a natural immune booster.
Make a tea infusion by adding boiling water to one small leaf in a mug and allow to draw for 5—7 minutes. It is exceptionally bitter, but beneficial. Consult a medical practitioner before ingesting if you are on medication. Rose pelargonium Capitatum or Graveolens : This fynbos has a grassy, fresh flavour and a rose scent and can be made into a cordial: gently simmer two large cups of rose pelargonium leaves in 1 litre of water for 10 minutes.
Remove the leaves and add two cups of sugar. Continue to simmer gently, stirring until the mixture thickens into a syrup. Allow to cool and add the juice of one lemon. Mix ml of cordial with 1 litre of chilled sparkling water and a rose pelargonium stalk to serve. Pansy flowers Viola spp : With their vivid colours, use these grassy and fresh-tasting flowers to garnish just about anything. Suggested by Roushanna.
Dandelions Taraxacum officinalis : Part of the daisy family, the flowers have a honey-like flavour when young but become bitter when mature. Add the flowers to salads and stir-fries; the young leaves can be eaten steamed or raw. Celebrate Spring by check out the Vase Ceramic Exhibition.
Find out where to see the best flowers this spring flower season. Explore the tour that Madiba did with Wildflower Safari. Discover spring events in August and September. Get active with our overview of hikes in Cape Town. Find your roots at one of these camping spots. Which is your favourite of these natural rockpools? Go on an adventure with these day tours. Join our newsletter and get quick access on the go by adding us to your mobile home screen for the ultimate guide to discoveries in Cape Town.
Win an off-the-grid luxury escape with The door closes. You have 60 minutes to get out Have the birthday party your child Cakes too beautiful to eat, short rib dumplings and gorgeous harbour views Craving a wild night out? Zsa Zsa Cape Pizza, beach vibes, cocktails, and stunning views, the recipe for a perfect day Spin Street Gallery: 18 years of Nic Virtual and on-site wine tastings at Staycations, outdoor adventures, local art, unique Every week something you don't want to miss. IP Address for personalized ads display and personalized content, ad and content measurement, audience insights, and product development and to create a personalized ads profile.
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