A morphometric study of variance in articulated dendritic phytolith wave lobes within selected species of Triticeae and Aveneae

Morphometric analysis has proven to be an effective tool for distinguishing among phytolith assemblages produced by closely related plant taxa. Elongate dendritic epidermal phytoliths are produced in the inflorescence bracts of many cereal species. Under light microscopy, these articulated dendritic phytoliths produce wave patterns between the margins of the cells that are reported to have taxonomic significance. In this study we explore morphometric variance among the lobes of the wave patterns formed by the articulated dendritic phytoliths within selected species of cereals as a first step towards understanding the variance between species. We found that there is often significant variance in dendritic wave lobes among different accessions of a species, among the different types of inflorescence bracts of the species (glumes, lemmas and paleae), and among each bract type’s location on the inflorescence (upper, middle and lower third of inflorescence spike or panicle). We observed that shape morphometries are typically more reliable and require a smaller sample size for statistical confidence than size morphometries. We further observed that adequate samples sizes for analysis of several shape morphometries of articulated dendritic wave lobes are considerably smaller than those reported to be required for analysis of the same morphometries of individual or isolated dendritic phytoliths. To gain a preliminary sense whether there is potential for discriminating between taxa in light of the significant variance within species, we compared our data to archaeological material from the historical center of Brussels. We demonstrate that while there is considerable variance in the morphometries among accessions, bract types and inflorescence locations within each species, there may yet be potential for discriminating between cereal species in archaeological samples by the morphometries of their dendritic phytolith wave lobes. We present one possible paradigm for conducting such analysis on archaeological material.     

New evidence for Neolithic rice cultivation and Holocene environmental change in the Fuzhou Basin,southeast China

A stratified profile of the Zhuangbianshan (ZBS) archaeological site (Fuzhou Basin, Fujian) was studied to investigate Neolithic era anthropogenic influence and associated environmental changes. Analysis of the archaeological sediments focused on phytoliths, palynomorphs and microcharcoal. Until now, a lack of direct evidence for agriculture has made it difficult to know if Neolithic cultures of this area relied on the exploitation of wild plants such as nuts and sago palm, or a combination of farming and foraging. Three types of rice phytoliths were found in ZBS archaeological deposits, providing robust evidence for rice farming as part of a broad-spectrum Neolithic subsistence economy centered on fishing and hunting. Chronologies based on AMS ¹⁴C dates and artifact typology place the earliest rice during the Tanshishan (TSS) Period (5,000–4,300 cal bp) followed by a shift to economic dependency on rice in the Huangguashan (HGS) Period (4,300–3,500 cal bp). The ZBS phytolith assemblage contains high frequencies of rice husk (peaked-shape glume cells) phytoliths, with far fewer leaf and stem types. This indicates late stage processing activities such as dehusking, implying a focus on consumption rather than rice production. High concentrations of charcoal in the Neolithic ZBS deposits indicate local human settlement and peaks in fire use. The ZBS pollen record also reflects human settlement and peaks in local forest clearance during the Neolithic. Forest cover was renewed when the site was temporarily abandoned following the Neolithic. Rapid formation of the Min River floodplain began ~2,000 cal bp in association with retreating sea level and intensifying anthropogenic influence. Prior to that, rice farming in the Fuzhou Basin was limited by the scarcity of wetlands suitable for agriculture.     

Bronze Age crop processing evidence in the phytolith assemblages from the ditch and fen around Fondo Paviani,northern Italy

The Terramare civilization (ca. 1650–1150 cal bce) on the Po plain in northern Italy is considered to have been an agrarian society typical of the European Bronze Age, with a subsistence economy based on arable and livestock farming, and which showed some innovations such as the introduction of millets as cultivars. Some questions are still open concerning the agricultural system, the food and non-food uses of plant resources and the organization of labour at these sites. In this paper, for the first time, phytolith analysis has been integrated with more standard archaeobotanical methods applied to material from the long-lasting settlement of Fondo Paviani, Verona. The aim of the study was to use phytoliths as a tool to investigate the cereal economy in order to detect different grass subfamilies and possibly provide hints about local crop processing activities. For this purpose, two contexts, a shallow ditch at the edge of the site that had been filled with domestic waste and a near-site fen with natural infilling, have been the objects of a multi-proxy inter-disciplinary investigation. This includes the analyses of phytoliths, pollen, NPP, sediment texture and micromorphology. The phytolith record shows remains of panicoid as well as pooid grasses, including chaff material with frequent traces of threshing that indicate the processing of cereals at the site and the possible use of chopped straw as fodder. The comparison of different kinds of evidence strengthens the interpretation and offers a new perspective on the application of phytolith analysis to Bronze Age northern Italy.     

Pollen molecular biology: Applications in the forensic palynology and future prospects: A review

Palynology, which is the study of pollen and spores in an archaeological or geological context, has become a well-established research tool leading to many significant scientific developments. The term palynomorph includes pollen of spermatophytes, spores of fungi, ferns, and bryophytes, as well as other organic-walled microfossils, such as dinoflagellates and acritarches. Advances in plant genomics have had a high impact on the field of forensic botany. Forensic palynology has also been used and applied more recently to criminal investigation in a meaningful way. However, the use of pollen DNA profiling in forensic investigations has yet to be applied. There were earlier uses of dust traces in some forensic analyses that considered pollen as a type of botanical dust debris. Pollen grains can be studied for comparative morphological data, clues to unexpected aspects relating to breeding systems, pollination biology and hybridization. This can provide a better understanding of the entire biology of the group under investigation. Forensic palynology refers to the use of pollen and other spores when it is used as evidence in legal cases to resolve criminal issues by proving or disproving relationships between people and crime scenes. This overview describes the various contributions and the significance of palynology, its applications, different recent approaches and how it could be further employed in solving criminal investigations.     

Identifying inflorescence phytoliths from selected species of wheat (Triticum monococcum, T. dicoccon, T. dicoccoides, and T. aestivum) and barley (Hordeum vulgare and H. spontaneum) (Gramineae)

Analysis of microfossil silica phytoliths is becoming an increasingly important research tool for taxonomists, archaeobotanists, and paleoecologists. Expanded use of phytolith analysis by researchers is dependent upon development of phytolith systematics. In this study phytoliths produced by the inflorescence bracts from four species of wheat, Triticum monoccocum, T. dicoccon, T. dicoccoides, and T. aestivum, and two species of barley, Hordeum vulgare, and H. spontaneum, were analyzed using computer-assisted image and statistical analysis with the intent to develop taxonomic tools to distinguish among the taxa. A classification key based on significant differences among the mean morphometries of the inflorescence phytoliths produced by each species was created and tested. Discriminant analysis of the morphometries of several morphotypes of phytoliths was also conducted to determine whether this computer-assisted statistical procedure could be used as another method to classify the taxa and to determine which morphotypes have measurements that can best be used in discriminant functions. Test results indicated that, at the genus level, both the classification key and discriminant analysis of certain morphotypes of phytoliths were relatively reliable tools for distinguishing among phytoliths produced in the inflorescence bracts of the taxa considered. For distinguishing among the taxa at the species level, the classification key was most reliable. Of the discriminant analyses tested, that based on all the phytolith morphotypes combined was more reliable than those based on only one morphotype.     

中国有机残留物分析的研究进展及展望

有机残留物分析,是指从残留物载体中提取有机分子,利用科技检测手段进行定性、定量分析,判断有机残留物的生物来源,从而了解古代动植物的加工、利用和相关载体的功能等.中国有机残留物分析工作已开展40余年,取得了很多进展,但仍需要更多重视.本文首先回顾了中国考古遗存研究中有机残留物分析的发展历程,然后梳理了动物制品、粮食作物制...     

A methodological approach to the study of microbotanical remains from grinding stones: a case study in northern Gujarat (India)

The thorough reconstruction of subsistence practices throughout human history remains one of the most challenging questions in archaeological research. Analyses of microbotanical remains recovered from archaeological artefacts have greatly contributed to our knowledge of past livelihood strategies. However, certain methodological issues are seldom addressed throughout these analyses, including the integration of multiple proxies, the comparison between samples and the interpretation of control samples. This paper addresses these methodological concerns through the analysis of phytoliths and starch grains from a total of 80 samples from grinding tools from four archaeological occupations (ca. 7150–1900 cal bc) in northern Gujarat (NW India). The results were compared with 26 control samples from the same sedimentary matrix from which the tools were recovered and 12 control samples from laboratory consumables. Multivariate statistics were applied to (a) compare control samples with grinding stones to assess sample contamination and representativeness, (b) compare samples from different sites, and (c) identify tool clusters within a site. This study stresses the importance of the integrated analysis of phytoliths and starch grains and the application of multivariate statistics, which allow for stronger interpretations on the use and post-depositional trajectories of grinding stones, thus offering a solid framework for the reconstruction of past subsistence strategies. Moreover, the results show that the inhabitants of northern Gujarat continuously exploited small millets throughout the Holocene and that pulses, secondary at first, became a fundamental part of their subsistence strategy with the advent of settled life.     

Taphonomie des plantes et interprétations paléoécologiques. Une synthèse

The taphonomy is a powerful and requisite tool for environmental reconstructions of ancient plant communities. Necrobiotic processes, which lead to the production of plant fragments, inform us on fossil plant physiology. Among the processes that can be drawn from necrobiotic studies is the retention of leaf organs on plants, the relative quantity of pollen grains produced by different fossil species or the significance of wildfire dynamics in ancient plant communities. Biostratinomy examination is a fundamental tool for elucidating fossil plant habitats. Numerous experimental data allow paleobotanists for evaluating the role of transport in the origin of fossil assemblages. Autochthonous plant assemblages, which are characterised by the preservation of fossil rooting structures, are relatively rare in the nature. In consequence, the search for palaeoecological information from parautochthonous to allochthonous assemblages has been a priority in taphonomy. As a result, taphonomic models have been elaborated in well-known sedimentological contexts, such as small lacustrine deltas, which allow for the distinction between riparian or perideltaic plant remains. Lithospheric processes modify plant debris after burial. The differences in the degrees of transformations (or alterations) during the diagenesis provide for information about the original morphology and biochemical composition of the plant tissues, which are also paleoecologically useful. Thus, amber diagenesis modifies resin biochemistry into new molecules that are still informative from the chemotaxonomical point of view.     

Hammer or crescent wrench? Stone-tool form and function in the Aurignacian of southwest Germany

The early Upper Paleolithic of Europe is associated with the appearance of blade/bladelet technology (e.g., Aurignacian). These industries include a wider range of formal tool types than seen in the Middle Paleolithic. Greater diversity in tool types is often interpreted as specialized tools created for specific tasks. This, in turn, is said to reflect dramatic behavioral shifts between Neandertals and modern humans. In order to test previous interpretations, it is necessary to have a detailed understanding of early Upper Paleolithic stone-tool function. Toward this end, analyses of microscopic residue and use-wear were undertaken on 109 stone tools from three Aurignacian sites in southwest Germany (Hohle Fels, Geissenkl?sterle, and Vogelherd). These cave sites evidenced remarkable residue preservation, with approximately 82% of the sample showing some form of functional evidence. Residues observed included hair, feathers, bone/antler, wood, plant tissue, phytoliths, starch grains, and resin. The results suggest that tool typology is not strongly linked to the processing of specific materials. For example, endscrapers from the sample show evidence of processing wood, charred wood, plants, starchy plants, birds, bone/antler, and animals (hair). Hairs are found on tools typologically classified as blades, flakes, borers, pointed blades, and combination tools (nosed endscraper-borer, burin-laterally-retouched blade). In the early Upper Paleolithic of southwest Germany, a wide range of tool types appears to have been used to process a diverse array of materials. These results suggest that the interpretation of behavioral patterns from stone tools must consider more than tool typology.     

Archaeobotanical evidence for early agriculture at Ljubjansko barje (Ljubljana Moor), central Slovenia

Archaeobotanical evidence is presented for early agriculture at southwestern Ljubljansko barje (Ljubljana Moor), Slovenia. Archaeobotanical finds from the Eneolithic site at Hočevarica, and pollen records from an archaeological profile and from a nearby core were analysed. Numerous charred grains of cultivated cereals together with fossil seeds of Chenopodium sp. demonstrate that during the occupation of the settlement at Hočevarica, agriculture was well established. The majority of identified grains were of Hordeum vulgare (cultivated barley) and the rest were Triticum monococcum and T. turgidum ssp. dicoccum (cultivated wheats). Large amounts of cereal pollen and pollen of Chenopodiaceae also suggest strong human impact on the surrounding vegetation and landscape. Pollen and archaeobotanical data from Hočevarica show a large consistency in timing of the appearance of agriculture. In the pollen record from the core at Hočevarica a significant increase (up to 40%) in cereal pollen was detected at 4881 ± 50 B.P. (3770-3630 cal B.C.). Charred cereal grains were dated to 4800 ± 40 B.P. (3650-3520 cal B.C.). The grains of cultivated cereals from Hočevarica represent the oldest archaeobotanical evidence for agriculture in central Slovenia. Received February 18, 2002 / Accepted October 21, 2002     

A freshwater analog for the production of Epiphyton‐like microfossils

Calcified microbial microfossils—often interpreted as cyanobacteria—were important components of Precambrian and Paleozoic limestones, but their paucity in modern marine environments complicates our ability to make conclusive interpretations about their taxonomic affinity and geologic significance. Freshwater spring‐associated limestones (e.g., travertine and tufa) serve as terrestrial analogs to investigate mineralization in and around aquatic biofilms on observable timescales. We document the diagenesis of calcite fabrics associated with the freshwater algae Oocardium stratum, an epiphytic colonial green algae (desmid) known for producing stalks of extracellular polymeric substances (EPS) and passively producing a bifurcating tubular calcite monocrystal. Bifurcating EPS stalks produced by Oocardium colonies can become calcified and preserved in ancient carbonate deposits. Calcified micritic EPS stalks have a filamentous morphology, show evidence of branching, and maintain uniformity in diameter thickness throughout the mm‐scale colony, much like the enigmatic calcimicrobe Epiphyton. We provide a mechanism by which calcification associated with a colonial semispherical micro‐organism produces microfossils that deceptively resemble filamentous forms. These findings have implications for the use of morphological traits when assigning taxonomic affinities to extinct microfossil groups and highlight the utility of calcifying freshwater modern environments to investigate microbial taphonomy.     

Understanding Fossil Phytolith Preservation: The Role of Partial Dissolution in Paleoecology and Archaeology

Opaline phytoliths are important microfossils used for paleoecological and archaeological reconstructions that are primarily based on relative ratios of specific morphotypes. Recent studies have shown that phytolith assemblages are prone to post-depositional alteration involving partial dissolution, however, the manner in which partial dissolution affects morphotype composition is poorly understood. Here we show that morphotype assemblages from four different plant species subjected to controlled partial dissolution are significantly different from the original assemblages, indicating that the stability of various morphotypes differs, mainly depending on their surface area to bulk ratios. This underlying mechanism produces distorted morphotype compositions in partially dissolved phytolith assemblages, bearing vast implications for morphotype-based paleoecological and archaeological interpretation. Together with analyses of phytolith assemblages from a variety of archaeological sites, our results establish criteria by which well-preserved phytolith assemblages can be selected for accurate paleoecological and archaeological reconstructions.     

城子崖遗址植硅体反映的生业经济模式

龙山文化是中国史前社会形态演进的关键阶段,亦是农业强化生产的关键时期。城子崖遗址是鲁北平原史前区域中心城址,其生业经济研究有助于理解该地区社会复杂化及文明进程。本文对城子崖遗址龙山时期不同遗迹单位的15份土样进行了系统的植硅体分析,尝试探讨了该遗址龙山文化时期的社会发展和生业经济水平、农作物生产和加工方式、野生植物资源利用情况以及各遗迹堆积及其所反映的人类行为活动信息。结果显示,该遗址龙山文化时期已形成粟、黍、稻、小麦、稗(可能)的农作物组合方式;同时,广泛采集利用聚落周边的自然植物资源,是农业与采集业并存发展的生业经济模式。先民在作物栽培中进行了锄草、灌溉等较为精细的管理,其中,黍较粟更具耐旱抗病特性,加上田间管理需求较低而被优先选择栽培。先民在收获作物时,采用类似割穗、掐穗等方法以减少作物茎秆及杂草混入,随后在户外进行小规模地脱壳、扬场工作。此外,根据灰坑中植硅体的组合特征可将其分为生活垃圾、谷物加工、蓄水淘米三个类型,水井和墓葬内的植硅体则分别与生活环境和丧葬环节等信息相关。     

The microfossil record of early land plants

Dispersed microfossils (spores and phytodebris) provide the earliest evidence for land plants. They are first reported from the Llanvirn (Mid-Ordovician). More or less identical assemblages occur from the Llanvirn (Mid-Ordovician) to the late Llandovery (Early Silurian), suggesting a period of relative stasis some 40 Myr in duration. Various lines of evidence suggest that these early dispersed microfossils derive from parent plants that were bryophyte-like if not in fact bryophytes. In the late Llandovery (late Early Silurian) there was a major change in the nature of dispersed spore assemblages as the separated products of dyads (hilate monads) and tetrads (trilete spores) became relatively abundant. The inception of trilete spores probably represents the appearance of vascular plants or their immediate progenitors. A little later in time, in the Wenlock (early Late Silurian), the earliest unequivocal land plant megafossils occur. They are represented by rhyniophytoids. It is only from the Late Silurian onwards that the microfossil/ megafossil record can be integrated and utilized in interpretation of the flora. Dispersed microfossils are preserved in vast numbers, in a variety of environments, and have a reasonable spatial and temporal fossil record. The fossil record of plant megafossils by comparison is poor and biased, with only a dozen or so known pre-Devonian assemblages. In this paper, the early land plant microfossil record, and its interpretation, are reviewed. New discoveries, novel techniques and fresh lines of inquiry are outlined and discussed.     

Palaeobotanical evidence for agricultural activities in the Eifel region during the Holocene: plant macro-remain and pollen analyses from sediments of three maar lakes in the Quaternary Westeifel Volcanic Field (Germany, Rheinland-Pfalz)

As a part of the ELSA-project (Eifel Laminated Sediment Archive) new pollen and plant macro-remain analyses have been carried out on a series of Holocene lacustrine sediments from three open maar lakes of the Quaternary Westeifel Volcanic Field. In combination with already existing pollen analyses, the archaeological record and written sources, the present study casts new light on settlement activities and henceforth the development of agriculture from the prehistoric to historic times in this region. While there are clues that wood pasturing was practised in the Eifel region from the Michelsberg Culture onwards (c. 4300 cal. b.c.), the Vulkaneifel is a remote area with relatively poor soils and a humid climate and was not constantly settled until the Late Neolithic/Early Bronze Age, when cereal pollen was found regularly in the deposits. Plant macro-remains (chaff), which give us direct evidence for arable agriculture in the surroundings of the maars, were also found in layers belonging to the Early Bronze Age (c. 1900 cal. b.c.). At the same time we can observe the massive spread of Fagus sylvatica (beech) in all pollen diagrams, which was most probably caused by a combination of climatic, anthropogenic and competitive factors. Later impacts of agriculture were an abundance of crop weeds and pollen in the following Middle Bronze Age. Nevertheless human impact remained discontinuous until the Urnfield Culture (1200–800 cal. b.c.). A layer of weeds dating at the end of the Urnfield Culture was found and also flax (Linum usitatissimum) cultivation first becomes apparent. However, the subsequent Iron Age and Roman Period reveal only crop weeds and cereal pollen in slightly higher concentrations, but the abundance of Poaceae pollen at this time is most probably consistent with grazing activities. There follows compelling evidence of the importance of flax cultivation and processing at the maars from the Merovingian Period (5th century a.d.) onwards. A detailed insight into the agriculture of the High Medieval comes from flash flood layers of the 14th century a.d., where remains of Secale cereale (rye) and crop weeds reflect winter-sown cultivation of rye. Cannabis sativa (hemp) was also cultivated and processed during the medieval. Finally we can trace the Prussian reforestation in the 19th century a.d., with an increase in Pinus sylvestris (pine) and Picea abies (fir), by both pollen and plant macro-remains.     

The development of plant food processing in the Levant: insights from use-wear analysis of Early Epipalaeolithic ground stone tools

In recent years, the study of percussive, pounding and grinding tools has provided new insights into human evolution, more particularly regarding the development of technology enabling the processing and exploitation of plant resources. Some of these studies focus on early evidence for flour production, an activity frequently perceived as an important step in the evolution of plant exploitation. The present paper investigates plant food preparation in mobile hunter-gatherer societies from the Southern Levant. The analysis consists of a use-wear study of 18 tools recovered from Ohalo II, a 23 000-year-old site in Israel showing an exceptional level of preservation. Our sample includes a slab previously interpreted as a lower implement used for producing flour, based on the presence of cereal starch residues. The use-wear data we have obtained provide crucial information about the function of this and other percussive tools at Ohalo II, as well as on investment in tool manufacture, discard strategies and evidence for plant processing in the Late Pleistocene. The use-wear analysis indicates that the production of flour was a sporadic activity at Ohalo II, predating by thousands of years the onset of routine processing of plant foods.     

Finger Millet processing in East Africa

Although archaeobotanical sampling and recovery programmes are a relatively recent implementation in East African archaeology, results from sites where they have been carried out follow a similar trend. This is one of abundant recovery of wood charcoal, but very little in the way of other macroscopic plant remains. Restricted archaeological evidence and ethnographic interviews show the importance of grains, in particular finger millet (Eleusine coracana), for the Bunyoro people of Uganda in pre-colonial times. It has been suggested that one of the possible reasons why finger millet is not being recovered in quantity from archaeological contexts is because the processing of this crop does not involve heating and hence there is not the chance of being deposited in charred form in the archaeological record. Recent ethnographic work on finger millet processing in Uganda shows that it is exposed to heat and potential charring during cleaning and preparation of the grain for either storage or cooking, and this regime is discussed in terms of its activities and products. These findings reinforce the need for archaeobotanists and archaeologists working in this region to look for other possible causes of the scarcity of macroscopic plant remains, and also the importance of considering integrated evidence for agricultural activity on prehistoric sites.     

A reconstruction of the history of a Holocene sand dune on Great Barrier Island, northern New Zealand, using pollen and phytolith analyses

Aim   To reconstruct the history of a Holocene sand dune using pollen and phytolith analyses, and to identify the strengths, weaknesses and compatibility of these two methods in the interpretation of Quaternary coastal environments.
Location  Great Barrier Island, northern New Zealand.
Methods  Pollen and phytolith analyses were carried out on a sequence through a Holocene sand dune containing a palaeosol.
Results  Phytoliths were present throughout the sequence. Grass phytoliths increased at the expense of tree phytoliths following fire disturbance. Pollen (and spores) was preserved only in the palaeosol part of the profile. Pteridium fern spores increased at the expense of tall tree pollen following the fire disturbance.
Main conclusions  Lack of phytolith production by many species and problems of taxonomic specificity in many others restricts the usefulness of phytolith analysis to defining only broad vegetation types. In New Zealand, gymnosperms are invisible in the phytolith record and ferns are extremely under-represented. In contrast, pollen analysis usually provides a great deal of information regarding the composition of a particular vegetation type. The loss of microscopic charcoal fragments during the phytolith extraction process is a disadvantage in the reconstruction of environments where fires have occurred. The greater durability of phytoliths compared with pollen means that phytoliths may be found in sediments where pollen has not been preserved. The phytolith record may also provide evidence of wetter environments that are not apparent in the pollen record. Unlike grass pollen, which is widely dispersed and therefore blurs the spatial record, the presence of grass phytoliths in sediments indicates a local source. The simultaneous application of both methods potentially provides a powerful tool in ecological interpretation and the reconstruction of Quaternary coastal environments.     

Vegetation dynamics in western Uganda during the last 1000 years: climate change or human induced environmental degradation?

A multi-proxy analysis of microfossils from sedimentary records, together with evidence from historical and archaeological data, has provided evidence of vegetation dynamics and human environment interactions in western Uganda for the last 1000 years. Pollen, fungal spores and phytoliths extracted from sediment cores obtained from a papyrus swamp at Munsa archaeological site indicate a relatively wet and forested environment in western Uganda prior to ca 1000 yr bp (cal 977–1159 ad ). A subsequent decline in forest vegetation occurred from ca 920 yr bp (cal 1027–1207 ad ). However, the deforestation period occurred during a wet period as registered in the River Nile water records, suggesting a human induced deforestation at Munsa rather than reduced precipitation. Increased numbers of herbivores, presumably domesticated cattle, postdeforestation are evidenced by the presence of dung fungal spores and broad accord with the archaeological evidence for initial occupation of the site at Munsa and the establishment of a mixed economy based on crops, cattle and iron working between 1000 and 1200 ad . From ca 200 yr bp (cal 1647–1952 ad ), forest recovery occurred at Munsa site and appears to reflect abandonment of the site, as suggested by archaeological evidence, possibly following a period of prolonged drought and famine between 1600 and 1800 ad , as recounted in the oral rich traditions of western Uganda and also reflected by low water levels of River Nile.     

Pollen accumulation rates as a tool for detecting land-use changes in a sparsely settled boreal forest

A peat profile from the village of Nellim in northern Finnish Lapland was analysed at a near-annual resolution in order to test to what degree of accuracy the land-use history of the village could be reconstructed on the basis of organic microfossils. The profile was first AMS ¹⁴C dated and a robust chronology constructed to enable near-annual sampling. A set of 47 contiguous samples were treated and counted to produce a pollen accumulation rate diagram (PAR, grains cm⁻² year⁻¹). PARs enabled a better distinction of the fine-scale human induced changes in the pollen assemblages than the classical percentage representation because real changes in each pollen taxon could be followed. Changes in the accumulation rate of pine pollen reflect regional changes in forest-use in Lapland and both local events and regional logging activity could be distinguished. Local within-mire changes were deduced from the peat stratigraphy and the testate amoebae. The limitations for using PARs seem to be connected to the physiology of the plants and the taphonomy of the different pollen types and this must be taken into account when making interpretations.