Irene Esteban

Raised field cultivation (camellones) is a Pre-Columbian technique, now abandoned, which is very extensive in the Llanos de Moxos (Bolivia). The objectives of the research were to understand the effects of human actions on the morphology, genesis and characteristics (especially redoximorphic features and chemical properties) of these soils on ridged fields and their past use. We studied five representative raised field (anthropogenic) soils and other non-anthropogenic soils around San Ignacio de Moxos and along the transect Trinidad-San Borja.
The non-anthropogenic soils are acidic, show a wide range of clay contents and different degrees of human activity according to their available phosphorus content. Soil-forming processes are related to fine fraction mobility and alternating redox conditions. Contrarily, the soils of the raised fields show a distinct pattern of redoximorphic features from ridge to channel. Moreover, ridges tend to be less acidic and have lower aluminium saturation than channels. Nevertheless, they have neither artifacts nor charcoal, and their colour and P content is similar to those of surrounding soils.
The raised fields appear to have been built to improve the drainage conditions. Chemical soil fertility was not the main issue and they were used for cultivation including maize. The set of characteristics encountered (differences in pH, and drainage status at a microscale) should be used to improve the classification of these anthropogenic soils.

The study of plant remains in archaeological sites, along with a better understanding of the use of plants by prehistoric populations, can help us shed light on changes in survival strategies of hunter-gatherers and consequent impacts on modern human cognition, social organization, and technology. The archaeological locality of Pinnacle Point (Mossel Bay, South Africa) includes a series of coastal caves, rock-shelters, and open-air sites with human occupations spanning the Acheulian through Middle Stone Age (MSA) and Later Stone Age (LSA). These sites have provided some of the earliest evidence for complex human behaviour and technology during the MSA. We used phytoliths—amorphous silica particles that are deposited in cells of plants—as a proxy for the reconstruction of past human plant foraging strategies on the south coast of South Africa during the Middle and Late Pleistocene, emphasizing the use and control of fire as well as other possible plant uses. We analysed sediment samples from the different occupation periods at the rock shelter Pinnacle Point 5–6 North (PP5-6N). We also present an overview of the taphonomic processes affecting phytolith preservation in this site that will be critical to conduct a more reliable interpretation of the original plant use in the rock shelter. Our study reports the first evidence of the intentional gathering and introduction into living areas of plants from the Restionaceae family by MSA hunter-gatherers inhabiting the south coast of South Africa. We suggest that humans inhabiting Pinnacle Point during short-term occupation events during Marine Isotope Stage (MIS) 5 built fast fires using mainly grasses with some wood from trees and/or shrubs for specific purposes, perhaps for shellfish cooking. With the onset of MIS 4 we observed a change in the plant gathering strategies towards the intentional and intensive exploitation of dry wood to improve, we hypothesise, combustion for heating silcrete. This human behaviour is associated with changes in stone tool technology, site occupation intensity and cli- mate change.

This is the first quantitative and morphological study of phytoliths from a diversity of plant species (56 spp., 23 genera and 14 families), growth forms (Restionaceae (restios) and Poaceae (grasses), bulbous plants, shrubs and trees) and plant parts (leaves, wood, scale leaves of the bulbs, culms and stems) from the Greater Cape Floristic Region (GCFR). The GCFR's south coast is an area with longest record of occupation by modern humans, and is thus of great archaeological significance. This study aims at building a phytolith reference collection of modern plants from the southern coast of the GCFR that are likely to have been used by past populations inhabiting the south coast of South Africa. A total of eighty phytolith morphotypes were identified in the whole data set. Poaceae and Restionaceae produced characteristic phytolith morphotypes that did not occur in other plant groups. Many other phytolith morphotypes occurred in more than one plant group. We confirmed that grasses are the highest phytolith producers. Restio phytoliths are unique characteristic of the Restionaceae and these are mainly derived from the parenchyma cells of the culms. The lack of diagnostic phytolith morphotypes that can be used for taxonomic identification in geophytes makes their identification difficult in the paleoanthropological record.

Despite phytoliths having been used to understand
past human use of plants and palaeoenvironment in Middle
Paleolithic sites, little is known on this aspect in the welldocumented
central region of Mediterranean Iberia. This paper
presents the first phytolith and mineralogical study conducted at
Abrigo de la Quebrada (Chelva, Valencia). Forty-one samples
were analyzed through phytoliths and Fourier transform infrared
spectroscopy (FTIR) from different areas, stratigraphic
levels, and archeological contexts (hearth, hearth-related, and
non-hearth-related sediments) of the shelter. The results obtained
point towards a different pattern of preservation in the site
depending firstly on the stratigraphy and secondly on the area
where the samples were collected. Postdepositional processes
that may have chemically affected phytolith preservation are
discussed. Grasses are the main plant component identified in
all the samples while woody plants are scarce. The abundance
of grasses in the non-hearth-related sediments might be related,
at least partially, to the dispersion of ashes from hearths, as
indicated by the FTIR results. The results are indicative of an
occupation of the site during the spring-autumn season. At this
time, the area would be dominated by a semi-open environment
with supramediterranean vegetation.

South Africa’s fynbos is the smallest of all known plant biomes and is geographically restricted to South Africa. It has high species richness and high endemism (hosts 8 600 plant species, 5 800 of which are endemic). Fynbos is composed mostly of evergreen shrubland vegetation characterized by the presence of restios, proteaids, ericoids, low presence of grasses and numerous herbaceous perennial geophytes (plants with bulbs, corms, tubers, or rhizomes). South Africa is also one of the regions that have received the attention of scholars researching the origins of modern humans. The importance of this region resides in the many caves and shelters containing well-preserved evidence of human activity, a growing number of early modern human fossils dating to the Middle Stone Age (MSA), and the presence of cultural material complexity. The area is also rich in edible geophyte plants and intertidal mollusk communities that could have supported these early homo populations. We present here the results of the phytolith study from modern soils of different vegetation units from the fynbos biome. The study is aimed at reconstructing, both, past environment and coastal subsistence patterns of these populations during the South African MSA. The phytolith morphological distribution and the phytolith concentration have been related to the physicochemical properties of soils, the environmental conditions and the characterization of the vegetation for the different study areas. Our results show that phytolith concentration and the phytolith morphological distribution are straightforwardly related to the type of soils and the vegetation type where samples were collected. Samples from fynbos present very low phytolith concentration, grasses were barely identified here being phytoliths from restios and the wood/bark of dicotyledoneous plants the dominant taxa. Conversely samples from Renosterveld present high phytolith content, with grasses dominating the phytolith assemblage and few presence of restios.

El estudio de fitolitos se ha establecido como una herramienta de gran eficacia para la reconstrucción de la vegetación en diferentes regiones africanas.  En este estudio se han utilizado sedimentos de suelos modernos procedentes de diversas comunidades vegetales pertenecientes al Reino Floral Capense, Sudáfrica, con el objetivo de probar el potencial de los conjuntos fitolitológicos para la caracterización de las mismas. De esto modo se pretende identificar cada tipo de vegetación a través del conjunto fitolitológico para la  identificación de los cambios de vegetación, y por ende de clima y medioambiente, en el registro paleontológico así como arqueológico.

Adaptation of early human populations is closely linked to climate, environment and the way in which they were able to utilize the available resources. Our research attempts to reconstruct the vegetation present at two archaeological sites during two decisive moments in the history of humankind: i) Olduvai Gorge (Tanzania) where first Homo habilis were identified, and ii) Mossel Bay (South Africa) occupied by early Homo sapiens populations.
Using phytoliths -siliceous microremains that reproduce the cellular tissue of plants- we try to reconstruct the vegetation of these two sites, to better understand the influence of the environment in human evolution. Our research includes the description and phytolith study of modern analogous landscapes which are later compared to the archaeological results. Fourier Transformed Infrared Spectroscopy (FT-IR) is used to determine the mineralogical components of sediments to understand the preservation conditions of the identified remains.
The results obtained to date at Olduvai Gorge have allowed reconstructing the vegetation of FLK and HWKEE areas, where the remains of Parantropus boisei and Homo habilis were recovered. Vegetation studies at Mossel Bay, have finalized at PP13B, showing the use of dicotyledonous leaf plants during low occupation moments. PP5/6 studies are still in process.

"Phytoliths are being used to reconstruct the vegetation at Pinnacle Point 5/6 (Mossel Bay) during the occupation of early Homo sapiens (∼100 ka). This work takes into account the results obtained from the study of the archaeological samples and their comparison to modern soils and plants from the area (Cape Floral region).  Our main goals lie in improving our understanding on the exploitation of vegetal resources by the first modern humans, with special emphasis on the use and control of fire. The taphonomic processes affecting phytolith preservation in both archaeological and modern soil samples play also an important role in this work for a more reliable interpretation.
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"The archaeological complex of Pinnacle Point (Mossel Bay, South Africa) is formed by a series of coastal caves and rock-shelters with human occupations since the Middle Stone Age. These sites have provided the earliest evidences for modern human behavior. The present research focuses on the study of vegetal resources at cave 5/6, emphasizing on the use and control of fire. Here we show an overview of the taphonomical processes affecting phytolith preservation in this site. This taphonomic information will be critical to conduct a more reliable interpretation of the original plant use in the cave.
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The capacity to detect remnants of fire usage in archaeological sites, along with a better understanding of its use by prehistoric populations, can help us to shed light on advances in pyrotechnology and consequent impacts on hominin cognition, social organization, and technology.  At the same time, little is known on the use of plant resources for other purposes such as diet during Middle Paleolithic and Middle Stone Age periods. Pinnacle Point 13B (PP13B) and 5/6 (PP5/6) are two of several South African Middle Stone Age (MSA) sites that show an abundant presence of visible lenses of burnt material and intact hearths associated to other different archaeological remains such as fauna, shells, lithics, etc.  Phytolith and mineralogical analyses, through Fourier Infrared Spectrometry (FTIR), at PP13B and PP5/6 have been used to identify the types of plants used as fuel in the hearths as well as other possible plant uses.  In PP13B the high alteration noted in general in the phytoliths is used as a marker to signal the areas with higher alkaline conditions related to dripping water and compared to FTIR results which shows the presence of dahalite that may also affect the phytoliths. On the contrary, the excellent preservation of multicellular structures from the epidermal leaves of dicotyledonous plants in some areas, suggests that these areas belonged to in situ structures with practically no chemical nor post-depositional alteration. A most interesting pattern is the abundance of dicotyledonous leaves in some of the samples, namely from the rear of the cave, which might point either to obtaining specific leaf-fuels for the fires, short-term fire activities or to other activities such as cooking. In PP5/6 phytoliths do not present strong signs of dissolution and their presence in the uppermost levels has been related to natural input either from aeolian transport or percolation from the upper vegetated levels.

Mossel Bay at Pinnacle Point is formed by a series of sea caves, from the Middle Stone Age in the south coast of South Africa. The caves preserve evidence that hunter-gatherers here were practicing many new modern behaviors, like the production of shell beads, pyrotechnology and consumption of sea foods.  We present the first results of phytolith studies from different stratigraphic units from Site PP5-6, in Mossel Bay and its comparison to soil samples from the same geographical area as well as to the results obtained from the phytolith study of cave PP13B. In parallel, FTIR analyses have been conducted in all samples to better understand the differential phytolith preservation noted.

The importance of South Africa lies in the many caves and rock shelters containing well preserved evidence of human activity, cultural material complexity and a growing number of early modern human fossils dating to the Middle Stone Age (MSA). South Africa also hosts the world's smallest floral kingdom, now called the Greater Cape Floristic Region (GCFR), with high species richness and endemism. We use phytoliths –amorphous silica particles that formed in epidermal cells of plants–in order to study the evolution of plant exploitation strategies by first modern humans and to understand the response of GCFR environments to glacial-interglacial cycles and rainfall shifts and its implication with the evolution of first modern humans that inhabited the south coast of South Africa during the Upper Pleistocene. In paleoanthropological research, improving our capacity to reconstruct past climatic and environmental conditions can help us to shed light on survival strategies of hunter- gatherers. To do this, one must use actualistic studies of modern assemblages from extant habitats to develop analogies for the past and improve paleoenvironmental reconstructions. Accordingly, this thesis contemplates fossil and modern material: i) archaeological sediment samples from Pinnacle Point 5-6 site (PP5-6) located on the south coast of South Africa; ii) modern plants from the GCFR and susceptible to have been exploited by first modern humans inhabiting the south coast; iii) modern surface soil samples from different GCFR vegetation types of the south coast of South Africa. The modern plant reference collection is the first quantitative and morphological study conducted with wood and leaves of trees and shrubs, leaves, bulb scale leaves and edible part of the bulb of geophytes, restios–Restionaceae and grasses–Poaceae from the GCFR on the south coast of South Africa. We observed that grasses are the highest phytolith producers among plant types. We reported through thin sections and SEM that the characteristic restio phytoliths belong to and characterize the Restionaceae family and have been detected in the parenchyma sheath of the culms. Geophytes did not produce diagnostic phytolith morphotypes that can be used for taxonomic identification what might make difficult their identification in the fossil record. The results of the modern surface soil samples showed that phytolith concentration relates mostly to vegetation types and the dominant vegetation rather than to the type of soils. More abundant phytoliths from Restionaceae and woody/shrubby vegetation are also noted from fynbos vegetation and grass phytoliths are a recurrent component in all the vegetation types in spite of being a minor component in the modern vegetation. The grass silica short cells (GSSCs) from these plants, however, suggest a mix of C3 and C4 grasses in most of the vegetation types with a major presence of the rondels ascribed to C3 grasses. The exceptions are riparian, coastal thicket and coastal forest vegetation, which are characterized by the dominance of C4 grass phytoliths. The study of the modern plants and soils from the surrounding areas of Pinnacle Point were used as proxy for the reconstruction of past human foraging strategies and paleoenvironmental reconstruction through the phytolith record from PP5-6 site. The study of the archaeological sediment samples from this site indicated a wide range of plants used by first modern humans inhabiting the area including wood, leaves and fruits of trees and shrubs, grasses and restios. We reported for the first time the presence of restios in the South African archaeological record through the study of phytoliths. From an environmental perspective, the changes observed in the phytolith record from Pinnacle Point deposits are indicative of vegetation movements accordingly to climate changes and sea level fluctuations, in a continuous regional mosaic of habitats.