Pollen Evidence Research Articles

Reconstruction of the Late Pleistocene to Late Holocene vegetation transition using packrat midden and pollen evidence from the Central Mojave Desert

Reconstruction of the Late Pleistocene to Late Holocene vegetation transition using packrat midden and pollen evidence from the Central Mojave Desert

Late Quaternary Vegetation Development Following Deglaciation of Northwestern Alexander Archipelago, Alaska

The Cordilleran Ice sheet covered most of southeastern Alaska during the Last Glacial Interval (LGI: Marine Isotope Stage 2). Ice began to recede from western Alexander Archipelago ~17,000 + 700 yr BP. In this study, pollen analysis and radiocarbon dating of three sediment cores were used to reconstruct, for the first time, the postglacial development of vegetation of the northwestern Alexander Archipelago during the past ~15,240 cal yr. Hummingbird Lake (HL), on southwestern Baranof Island, yielded a sediment core with one of the longest dated records from southeastern Alaska. The earliest part of the HL pollen record (~15,240-14,040 yr BP) indicates that the earliest vegetation was pine (Pinus contorta subsp. contorta) parkland with willows (Salix), heaths (Ericaceae), sedges (Cyperaceae), grasses (Poaceae), herbs and ferns. Starting at ~14,040 yr BP, alder (Alnus) rapidly colonized the area as pine populations declined. By 11,400 yr BP, Sitka spruce (Picea sitchensis) colonized the area, and soon became the dominant conifer. Mountain hemlock (Tsuga mertensiana) also colonized the area by ~11,400 yr BP, followed by western hemlock (Tsuga heterophylla) at ~10,200 yr BP. By ~9200 yr BP, western hemlock had become the dominant species in the area. During the late Holocene yellow cedar (Chamaecyparis nootkatensis) became established. Two marine sediment cores were also analyzed for pollen, with the oldest core from Lower Sitka Sound, between Kruzof and Baranof Islands. The lower part of the core consists of interlayered tephras and freshwater lake muds that are estimated to be ~14,000 yr BP to 13,150 yr BP. Pollen evidence indicates that the early postglacial vegetation around Sitka Sound was pine parkland with alders and abundant ferns. Damage to vegetation around Sitka Sound by volcanic eruptions is suggested by abrupt, large shifts in percentages of alder and pine pollen, and fern spores in samples adjacent to tephra layers. A marine sediment core from Slocum Arm, a fiord on the western coast of Chichagof Island, has a basal age of ~10,000 yr BP. The pollen record is similar to the Holocene pollen record at Hummingbird Lake.

Loess is More: The Spatial and Ecological History of Erosion on China’s Northwest Frontier

AbstractThis is a paper about the speed and intensity with which new and intensive human land use in a semi-arid environment can bring about large-scale environmental change. In particular, this paper pinpoints how and why it was that the Yellow River shifted from a long-term condition of relative stability to a later state of frequent floods and course changes in the eleventh century. It is possible to trace the environmental history of this dramatic and sudden change of state with precision and confidence. Historical sources that record the dates and characteristics of flood events downstream align well with those that note the locations and dates of human activity upstream. More important, each aligns well not only with one another, but also with information from environmental science: sediment cores that preserve soil and pollen evidence for the timing and processes of systematic change.

Palynology of Middle Stone Age spring deposits in grassland at the Florisbad hominin site, South Africa

New pollen evidence and a review of past palynological research at the Pleistocene Florisbad thermal spring mound, which produced faunal, hominin and archaeological remains, allow a reconstruction of past conditions in the central Free State grassland, South Africa. Pollen sequences at the spring consist of alternating pollen-rich organic peaty horizons interrupted by hiatuses or pollen-poor layers of sandy and clayey deposits. The paleoclimatic interpretation of pollen sequences in springs like Florisbad, which contain a mixture of local and regional pollen and are influenced by spring mound cycles and changes in swamp configuration, requires consideration of taphonomy and site geomorphology to separate local from regional influences. By correlating the pollen stratigraphy in different parts of the site we suggest that the lower layers containing the Florisbad hominin (dated to 259 ka) and its associated Middle Pleistocene fauna, experienced cool moist and grassy conditions. Dating of some of the overlying Middle Stone Age layers suggest that they encompass the Last Interglacial period (MIS 5e; ca. 124–119 ka). In these levels the pollen evidence of upland fynbos shrubs unexpectedly suggests that cool conditions prevailed. This raises questions about the taphonomy, precision of the age estimate of occupation or the way we interpret pollen spectra.

Life habits and evolutionary biology of new two-winged long-proboscid scorpionflies from mid-Cretaceous Myanmar amber

Long-proboscid scorpionflies are enigmatic, mid-Mesozoic insects associated with gymnosperm pollination. One major lineage, Aneuretopsychina, consists of four families plus two haustellate clades, Diptera and Siphonaptera. One clade, Pseudopolycentropodidae, from mid-Cretaceous Myanmar amber, contains Parapolycentropus. Here, we newly establish Dualula, assigned to Dualulidae, constituting the fifth lineage. Parapolycentropus and Dualula lineages are small, two-winged, with unique siphonate mouthparts for imbibing pollination drops. A cibarial pump provides siphonal food inflow; in Dualula, the siphon base surrounds a hypopharynx housing a small, valved pump constricted to a narrow salivary duct supplying outgoing enzymes for food fluidization. Indirect evidence links long-proboscid mouthpart structure with contemporaneous tubulate ovulate organs. Direct evidence of gymnospermous Cycadopites pollen is associated with one Parapolycentropus specimen. Parapolycentropus and Dualula exhibit hind-wing reduction that would precede haltere formation, likely caused by Ultrabithorax. Distinctive, male Aneuretopsychina genitalia are evident from specimens in copulo, supplemented by mixed-sex individuals of likely male mating swarms.

The origin and spread of olive cultivation in the Mediterranean Basin: The fossil pollen evidence

Olive ( Olea europaea L.) was one of the most important fruit trees in the ancient Mediterranean region and a founder species of horticulture in the Mediterranean Basin. Different views have been expressed regarding the geographical origins and timing of olive cultivation. Since genetic studies and macro-botanical remains point in different directions, we turn to another proxy – the palynological evidence. This study uses pollen records to shed new light on the history of olive cultivation and large-scale olive management. We employ a fossil pollen dataset composed of high-resolution pollen records obtained across the Mediterranean Basin covering most of the Holocene. Human activity is indicated when Olea pollen percentages rise fairly suddenly, are not accompanied by an increase of other Mediterranean sclerophyllous trees, and when the rise occurs in combination with consistent archaeological and archaeobotanical evidence. Based on these criteria, our results show that the southern Levant served as the locus of primary olive cultivation as early as ~6500 years BP (yBP), and that a later, early/mid 6th millennium BP cultivation process occurred in the Aegean (Crete) – whether as an independent large-scale management event or as a result of knowledge and/or seedling transfer from the southern Levant. Thus, the early management of olive trees corresponds to the establishment of the Mediterranean village economy and the completion of the ‘secondary products revolution’, rather than urbanization or state formation. From these two areas of origin, the southern Levant and the Aegean olive cultivation spread across the Mediterranean, with the beginning of olive horticulture in the northern Levant dated to ~4800 yBP. In Anatolia, large-scale olive horticulture was palynologically recorded by ~3200 yBP, in mainland Italy at ~3400 yBP, and in the Iberian Peninsula at mid/late 3rd millennium BP.

Pollen evidence of floristic turnover forced by cool aridity during the Oligocene in Colorado

Pollen evidence of floristic turnover forced by cool aridity during the Oligocene in Colorado

The Akchagylian stage (late Pliocene-early Pleistocene) in the North Caspian region: Pollen evidence for vegetation and climate change in the Urals-Emba region

Samples from 12 drillhole-cores from the Urals-Emba region to the north-east of the Caspian Sea were analysed for pollen and spores. The records reveal vegetation and climate changes for the late Pliocene to early Pleistocene within the time interval from ca. 3.6 to ca. 1.65 Ma. According to the results of the pollen analysis, at the beginning of the Akchagylian stage (3.6–3.4 Ma) there was a cooling and change in structure of the dendroflora, and steppe-dominated landscapes were present. At the end of the early Akchagylian, and continuing into the middle Akchagylian, a maximum variety of pollen from tree species occurred. The presence of mesophilic and thermophilic elements signifies a moderately warm and humid climate occurred at around 3.2 Ma, probably related to the ‘Mid-Pliocene Warm Period’. A second major cooling occurred at around 2.5 Ma coinciding with the onset of northern hemisphere glaciations. During this time, coniferous forests dominated by Picea, Pinus and Abies with lesser numbers of broad-leaved trees were established. At the end of the Akchagylian, at around 1.8 Ma, the climate became more arid and steppe landscapes were re-established. During the Akchagylian, alternations between forest- and steppe-dominated landscapes occurred at least three times in the Urals-Emba region. Results are compared with pollen spectra in surface samples, and with ostracods and foraminiferal assemblages in cores from the study region.

Palynology of Iron Age and Gallo-Roman archaeological sediments from Beaurieux Les Grèves, Aisne, France

Pollen and non-pollen palynomorph analyses conducted on archaeological sediments from ditches and pits are used to investigate land-use and vegetation history around the long-lived rural settlement of Beaurieux Les Greves in the Aisne valley, Picardy, northern France. Samples were examined from successive phases spanning the 8th century bc to the 3rd century ad. Each phase showed evidence of agriculture and human impact on the environment. The earliest occupation was during the early Iron Age, and the area around the site was shown to have been almost completely deforested and mainly pasture. The later Iron Age supported mixed agriculture, probably with pasture around the settlement site and cereal fields further away. In Gallo-Roman times there was mixed farming with considerable cereal cultivation, although the area near the site was mainly pasture or abandoned land. Late Gallo-Roman times saw a reduction in agricultural activity and some regeneration of heath and scrub vegetation. Coprophilous fungal spores are conspicuous and indicate the importance of animal husbandry on and around the site. The data from Beaurieux Les Greves augment earlier analyses from settlements and natural deposits in the Aisne valley in suggesting almost complete deforestation for agricultural land use within the valley bottom, although some woodland undoubtedly survived on the steeper valley sides and nearby plateaux. It agrees with the pollen evidence from the wider region of north-eastern France that shows clearance of Fagus-dominated woodland for mixed agriculture in late Iron Age and Gallo-Roman times, and increasingly for arable cultivation. This was responsible for effecting a transformation from a partly wooded to a mainly open landscape.

The 8.2 ka cooling event in coastal East Asia: High-resolution pollen evidence from southwestern Korea

In this study, we present a high-resolution multi-proxy record (pollen, magnetic susceptibility, and mean grain size) from Bigeum Island, South Korea, which mainly showed early Holocene paleoenvironmental change. Bigeum pollen records indicated that early Holocene climate variations in coastal East Asia were principally controlled by the Atlantic meridional overturning circulation. Most importantly, the 8.2 ka cooling event was clearly recognized for the first time in coastal East Asia, where few high-resolution proxy data, such as ice core and stalagmite δ18O records, are available. The insular vegetation in the study site was extremely susceptible to even short-term climate changes, such as the 8.2 ka cooling event, which allowed a detailed climate reconstruction from pollen data. Early Holocene climate teleconnections between coastal East Asia and other regions were identified through regional comparisons of Greenland, China, Brazil, Spain, Madagascar, and Korea. Coastal East Asia is one of world’s most populated regions and will be particularly vulnerable to future climate change. Accurate and detailed paleoclimate proxy data, such as the Bigeum pollen record, will therefore be increasingly important in this region.

Pollen evidence of medicine from an embalming jar associated with Vittoria della Rovere, Florence, Italy

Various samples of human viscera fragments, sponges, and cloth were collected from embalming jars belonging to members of the Medici family of Florence. One jar was labeled with the name Vittoria della Rovere, who died in March of 1694. This jar contained viscera fragments that were identified as a section of collapsed intestine. The intestine of the Vittoria della Rovere sample contained a large concentration of pollen belonging to the Myrtaceae family. The Myrtaceae pollen was sometimes observed in clusters during analysis, which is indicative of purposeful ingestion of flowers, buds, or a substance derived from floral structures. Thus, the high concentrations and clustering of Myrtaceae pollen grains recovered from this sample are reflective of dietary or medicinal practices. Scanning electron microscopy indicated that the pollen was from cloves, Syzygium aromaticum. It is most likely that Vittoria della Rovere consumed cloves for medicinal or culinary reasons shortly before death.

Environmental changes and human activity since the Neolithic: Evidence from pollen and phytoliths in Hochung, Sai Kung area, Hong Kong

An excavation has revealed in Hochung, in the Sai Kung area of Hong Kong, which mainly deposited during the Middle to Late Neolithic period. Base on pollen and phytolith analysis, and combine with pervious published report reconstructed the paleoenvironmental changes around the archeological site. Results show that the settings around the Hochung site changed from river bank, lagoon to floodplain marsh and finally changed to cultivated land during Middle to Late Holocene. Evidence of pollen and phytoliths, coupled with the excavated relics, revealed that the Neolithic culture was characterized by fishing and hunting at ~4200–3500 yr BP, without evidence of rice cultivation or other agricultural activity in this area. Until the Tang and Song Dynasties, rice cultivation appeared based on pollen and phytolith assemblages, but the area of excavated site was not yet an in situ rice field. During the Ming and Qing dynasties, rice agriculture flourished, and the area turned into a local paddy field, lasting until 1960s. Meanwhile, the gradual reduction of evergreen broad-leaved trees and the increase of pioneer plants such as Dicranopteris and other secondary plants since the Tang and Song dynasties imply that the expansion of human agricultural activity caused serious damage to the natural evergreen broad-leaved forest. In the history period, the agriculture civilization has very closely relationship between the south area and the north area, especially from the Qin Dynasty to present.

How palynology could have been paepalology: the naming of a discipline

ABSTRACTFrom its ‘modern’ pollen-analytical beginnings, the science of what we now term palynology wrestled with terminology and sought an acceptable name for the discipline. Starting in 1943, the mimeographed Pollen Analysis Circular, edited from Ohio by Paul Sears, led to discussion of the content, organisation and naming of a developing discipline. This came to a head in 1944 with Ernst Antev's plea for ‘The Right Word’ and the suggestion of the word ‘palynology’ from the Cardiff duo of Harold Hyde and David Williams. In the search for a suitable term, Hyde consulted Cardiff-based Irish classicist Leopold Richardson who advised against the word palynology and suggested six alternatives. Hyde, however, was wedded to the term palynology and, in the interests of euphony and ‘hankering after my own offspring’, was seemingly able to overcome Richardson's scholarly objections by argument. Hyde and Williams defined palynology as ‘the study of pollen and other spores and their dispersal, and applications thereof’. This was considered an advance because alternative terms such as pollen analysis, pollen statistics and pollen science did not include the application or interpretation of pollen evidence. The term palynology quickly found acceptability within the pages of the Pollen Analysis Circular and subsequently received an airing in Nature. Once palynology was adopted by the influential Swede Gunnar Erdtman, it was rapidly accepted by the palaeoecological community.

Pollen and Sporormiella evidence for terminal Pleistocene vegetation change and megafaunal extinction at Page-Ladson, Florida

Two cores from the Page-Ladson archaeological site, Florida were analyzed for pollen and the dung fungus Sporormiella. The cores contained stratified deposits spanning the Pleistocene-Holocene transition: a period characterized by the widespread extinction of Pleistocene megafauna and abrupt changes in vegetation type and distribution. The disappearance of Sporormiella, a well-established proxy for large herbivore abundance, by ∼12,700 cal BP is consistent with the timing of Terminal Pleistocene megafaunal extinction elsewhere in North America. However, a resurgence of Sporormiella between ∼10,750–10,200 cal BP suggests an Early Holocene incursion of extant megaherbivores such as bison. Pollen evidence from the site also reflects dramatic vegetation changes, which are likely a response to both changing climate and fluctuating herbivore populations. Prior to 14,500 cal BP, the pollen assemblage reflects a relatively cool and dry climate. Between ca. 14,500–12,600 cal BP, the sediments are characterized by an increase in hardwood forest and mesic plant taxa, indicating an increase in both temperature and precipitation. After 12,600 cal BP, a decrease in arboreal pollen, with the exception of oak, alongside an increase in herbaceous pollen, indicates drier, warmer conditions. These results contextualize changes in human behavior at the onset of the Holocene.

Pollen evidence for a mid-Holocene East Asian summer monsoon maximum in northern China

There is a controversy regarding whether the high precipitation delivered by an intensified East Asian summer monsoon occurred during the early Holocene, or during the middle Holocene, especially in the context of the monsoonal margin region. The conflicting views on the subject may be caused by chronological uncertainties and ambiguities in the interpretation of different climate proxies measured in different sedimentary sequences. Here, we present a detailed record of the Holocene evolution of vegetation in northern China based on a high-resolution pollen record from Dali Lake, located near the modern summer monsoon limit. From 12,000–8300 cal BP, the sandy land landscape changed from desert to open elm forest and shrubland, while dry steppe dominated the hilly lands and patches of birch forest developed in the mountains. Between 8300 and 6000 cal BP, elm forest was extensively distributed in the sandy lands, while typical steppe covered the hilly lands and mixed coniferous–broadleaved forests expanded in the mountains. Our pollen evidence contradicts the view that the monsoonal rainfall increased during the early Holocene; rather, it indicates that the East Asian summer monsoon did not become intensified until ∼8000 cal BP in northern China. The low precipitation during the early Holocene can be attributed to the boundary conditions, i.e., to the remnant high-latitude Northern Hemisphere ice sheets and the relatively low global sea level.

Questioning the reliability of “ancient” woodland indicators: Resilience to interruptions and persistence following deforestation

Indicator species can provide invaluable insights into environmental conditions but robust empirical testing of their effectiveness is essential. Ancient woodland indicators (AWIs) are plant species considered indicative of sites that have been continuously wooded for a long period by virtue of poor dispersal ability and intolerance of non-woodland habitats. Many countries now utilise AWI species lists to classify ancient woodlands. Here we use a metastudy approach to test resilience of AWIs to interruptions and persistence following deforestation − and thus the robustness of using AWI lists − using a novel approach. We compare current AWI assemblage with woodland history based on pollen evidence at nine sites across the UK with a robustly-dated and spatially-precise palynological profile. Sites were split into: (1) proven continuous woodland; (2) previously interrupted woodland; and (3) previously but not currently wooded. Vegetation history was >1000years at most sites. Assessment of ancientness using AWIs agreed with palynologically-proven ancient woodland at two sites, including a species-poor woodland of previously-uncertain age. However, four interrupted woodland sites and three clear-felled sites supported extensive AWI floristic communities. This suggests AWIs are resilient to interruptions, possibly by remaining in the seed bank longer than expected, and persistent following deforestation. Persistence might be due to other species (e.g. heathland plants) acting as pseudo-canopy or because some AWIs are more tolerant of non-woodland locations than previously thought. We conclude that use of floristic AWIs alone in defining ancient woodland should be reviewed, especially where status links to planning policy and conservation prioritisation. We suggest species on AWI lists be reviewed under expert and local guidance and a system of weighting species based on their strict or strong affinity solely with ancient woodland be developed. The use of multi-taxa indicators is recommended to allow stakeholders globally to make informed decisions about ancient woodland status.

Vegetation Changes and Woodland Management Associated with a Prehistoric to Medieval Burnt Mound Complex at Ballygawley, Northern Ireland

ABSTRACTThis paper examines the impact on woodlands associated with burnt mound use from floodplain sediments and peats, using a combination of pollen, non-pollen palynomorphs, micro- and macro-charcoal and worked wood for the first time. We present this data from a multi-period burnt mound complex, dating from the Late Neolithic to the Medieval period, at Ballygawley, Co. Tyrone, Northern Ireland, to reconstruct vegetation changes from the Neolithic onwards and establish the significance of these changes, in particular on woodlands whilst the burnt mounds were in use. The findings from the macroscopic charcoal suggests the most abundant trees were commonly, but not exclusively, exploited. Local woodland was seemingly unaffected by use of burnt mounds during the Neolithic and early Bronze Age based on pollen evidence. A sustained increase in microscopic charcoal coincides with a permanent decrease in alder-carr woodland during a period of near continuous burnt mound use between 1725 and 530 BC, and a second phase of high microscopic charcoal values, c. AD 880, corresponds to the end of the penultimate phase of burnt mound use. Evidence from the worked wood suggests that some form of woodland management was used for hazel from the Neolithic onwards.

The late‐Holocene decline of Tilia in relation to climate and human activities – pollen evidence from 42 sites in southern Sweden

AbstractAimThe dominant role of Tilia in primeval forests of Scandinavia has long been recognized, but the timing and mechanisms for its decline have not been completely unravelled. A particular uncertainty involves the balance between climate and human activities as the drivers of the change. One reason for the uncertainty is the challenge in evaluating the past cover of the genus owing to its poorly dispersed pollen; another is that a multi‐site study would be required to trace subregional differences. To overcome these obstacles, we here apply two different analytical methods to pollen data from 42 sites in two distinct vegetation zones of Sweden.LocationTemperate and hemi‐boreal vegetation zones of southern Sweden.MethodsGeneralized additive mixed models (GAMM) were used to model the development of Tilia and cereal pollen percentages over time. Twelve sites were used for reconstruction of local cover of Tilia using the landscape reconstruction algorithm (LRA).ResultsBefore 4000 cal. bp the Tilia mean pollen percentages were similar in the two vegetation zones. Thereafter, values in the hemi‐boreal zone declined, with less Tilia since around 3000 cal. bp. In contrast, Tilia did not decrease in the temperate zone until this past millennium. The LRA application revealed that in some forests a large cover of Tilia remained considerably longer than has traditionally been estimated by pollen percentages alone.Main conclusionsBy using a large coherent dataset we found significant differences in how the abundance and distribution of Tilia changed through time between two adjacent vegetation zones. We interpret the initial decline in the northern hemi‐boreal zone to be driven by cooling climate, and the later decline in the southern temperate zone to be driven more by human land‐use.

Assessment of pollen assemblages on footwear for evidence of pollen deriving from a mock crime scene: a contribution to forensic palynology

To provide evidence of a link between a crime scene and a suspect, pollen analysis is occasionally employed. However, experimental research linking pollen on footwear to a specific crime scene has been infrequently undertaken such that there are limited references to cite in court. In this blind study, the author had to determine, which of 12 pairs of footwear had walked on a mock scene by comparing their assemblages to those of two scene controls. An additional four control pairs of footwear that had not been worn on or near the scene were also analysed. The pollen data from the footwear was assessed and compared with the scene control samples for: number of taxa, key types, Czekanowski Coefficient and general assemblages. Results indicated that six of the pairs of footwear had walked on the scene and these were, indeed, the ones that actually had done so. The four control pairs were dissimilar in most aspects, particularly key types. This research demonstrates, with some limitations, that evidence of a match between footwear sample and location can be found, even when material from other habitats is present on an exhibit.

False Blister Beetles and the Expansion of Gymnosperm-Insect Pollination Modes before Angiosperm Dominance

During the mid-Cretaceous, angiosperms diversified from several nondiverse lineages to their current global domination [1], replacing earlier gymnosperm lineages [2]. Several hypotheses explain this extensive radiation [3], one of which involves proliferation of insect pollinator associations in the transition from gymnosperm to angiosperm dominance. However, most evidence supports gymnosperm-insect pollinator associations, buttressed by direct evidence of pollen on insect bodies, currently established for four groups: Thysanoptera (thrips), Neuroptera (lacewings), Diptera (flies), and now Coleoptera (beetles). Each group represents a distinctive pollination mode linked to a unique mouthpart type and feeding guild [4-9]. Extensive indirect evidence, based on specialized head and mouthpart morphology, is present forone of these pollinator types, the long-proboscid pollination mode [10], representing minimally ten family-level lineages of Neuroptera, Mecoptera (scorpionflies), and Diptera [8, 10, 11]. A recurring feature uniting these pollinator modes is host associations withginkgoalean, cycad, conifer, and bennettitalean gymnosperms. Pollinator lineages bearing these pollination modes were categorized into four evolutionary cohorts during the 35-million-year-long angiosperm radiation, each defined by its host-plant associations(gymnosperm or angiosperm) and evolutionary pattern (extinction, continuation, or origination) during this interval [12]. Here, we provide the first direct evidence for one cohort, exemplified by the beetle Darwinylus marcosi, family Oedemeridae (false blister beetles), that had an earlier gymnosperm (most likely cycad) host association, later transitioning onto angiosperms [13]. This association constitutes one of four patterns explaining the plateau of family-level plant lineages generally and pollinating insects specifically during the mid-Cretaceous angiosperm radiation [12].