Fossil Pollen Analysis Research Articles

A new approach to counting fossil and modern pollen grains: The orderly count

Palynology, the study of pollen and spores, plays a crucial role in various scientific disciplines, including earth sciences (paleovegetation and paleoclimatology), botany, allergy, archaeology, forensic sciencs and cosmetics. This study delves into the critical question in fossil pollen analysis studies: the minimum count of pollen grains required for accurate estimation of vegetation composition. Various statistical methods have been proposed over the years to address this question. Our research introduces an alternative technique, the orderly count, tailored to the nature of palynological analysis. We apply this method to diverse sediment catchments, including peat bogs, marine and lake sediments, from different geographical locations. Additionally, we revisit the reliability coefficients and propose adjustments for more accurate results. Our findings suggest that relying on statistical methods without considering the specific characteristics of palynological data may lead to low reliability. We advocate for the integration of dissimilarity criteria and the orderly count in sample size assessments for enhanced accuracy in palynological analyses. Our study emphasizes the importance of choosing appropriate methodologies aligned with the unique aspects of palynology to ensure robust and reliable results.

Contribution to the Pollen Morphology of the Family Capparaceae

Present work deals with a detailed palynological investigation on 147 species distributed over 23 genera of the family Capparaceae. Most of these are Asian and African species with few American ones.Pollen characters have been found useful in the delimitation of subfamily, tribe and genera to certain extent. In certain cases interspecific relationship is exposed by correlating pollen and seed characters together.This study will be helpful in the living and fossil pollen analysis.

Holocene climate variability and the effect of anthropogenic activities on the vegetation landscape of western-central Mexico

Atmospheric forcings control climate variability and at the same time control vegetation distribution and forest fires during the Holocene. Paleoenvironmental studies are scarce in western Mexico, particularly those documenting vegetation change, landscape dynamics, and fire regimes. This study presents a vegetation and fire occurrence reconstruction in the Etzatlán-Magdalena paleolake, western Mexico, during the Holocene. The reconstruction relies on fossil pollen, macrocharcoal and microcharcoal analyses of a clay sediment core. In the early Holocene (10–5.8 ka), climatic conditions were humid between 10 and 9 ka, represented by cloud forest of Liquidambar, Juglans, and Betulaceae. After 9 ka Quercus forest expanded and a trend towards warm conditions was detected, associated with high fire activity, suggesting the presence of a dry forest. Fire episodes at local and regional scale had a long-term negative effect on temperate and cloud forests. In the middle Holocene (5.8–2.1 ka), temperate forest was replaced by dry forest, indicating a drier climate. In the late Holocene (2.1–0.3 ka), the expansion of disturbance taxa and the low local fires indicated an open landscape and dry conditions. Human activity was documented by an increase of Cheno-Amaranthaceae, Poaceae and microcharcoal concentration after 3.5 ka. This research provides relevant information on the vegetation dynamics in a region with a long history of human settlement.

Vegetation and climate change at the southern margin of the Neo-Tethys during the Cenomanian (Late Cretaceous): Evidence from Egypt.

Changes in terrestrial vegetation during the mid-Cretaceous and their link to climate and environmental change are poorly understood. In this study, we use plant macrofossils and analysis of fossil pollen and spores from the Western Desert, Egypt, to assess temporal changes in plant communities during the Cenomanian. The investigated strata have relatively diverse sporomorph assemblages, which reflect the nature of parent vegetation. Specifically, the palynofloras represent ferns, conifers, monosulcate pollen producers, Gnetales, and a diverse group of angiosperms. Comparisons of both, dispersed palynoflora and plant macrofossils reveal different characteristics of the palaeoflora owing to a plethora of taphonomical and ecological biases including the depositional environment, production levels, and discrepancies between different plant organs. A combination of detailed records of sporomorphs, leaves, and charcoal from the studied successions provide new understandings of the palaeoclimate and palaeogeography during the Cenomanian and Albian-Cenomanian transition in Egypt. The mixed composition of the palynofloral assemblages reflects the presence of different depositional situations with a weak marine influence, as evidenced by a minor dinoflagellate cysts component. The local vegetation comprised various categories including herbaceous groups including ferns and eudicots, fluvial, open environments, and xeric arboreal communities dominated by Cheirolepidiaceae and perhaps including drought- and/or salt-tolerating ferns (Anemiaceae) and other gymnosperms (Araucariaceae, Ginkgoales, Cycadales, and Gnetales) as well as angiosperms. The presence of riparian and freshwater wetland communities favouring aquatic and/or hygrophilous ferns (of Salviniaceae and Marsileaceae), is noted. The wide variation of depositional settings derived from the palynological data may be attributed to a prevalent occurrence of producers in local vegetation during the early Cenomanian of Egypt. For the purpose of this work on the studied Bahariya Formation and its equivalent rock units, where iconic dinosaurs and other fossil fauna roamed, we attempt to improve the understanding of Egypt's Cenomanian climate, which is reconstructed as generally warm and humid punctuated by phases of considerably drier conditions of varying duration.

Climatic and Ecological Changes in the Subtropical High Andes During the Last 4,500 Years

The effects of climate change may be more evident in mountainous areas. In these areas, an increase in temperature and a decrease in precipitation can reduce the amount of snow, which represents a source of water for human consumption and vegetation. To analyze the effects of climate change on vegetation, it is possible to examine the climate–vegetation relationship in the past and observe the influence of variation in temperature and precipitation on the dynamics of plant communities. The aim of the present work was to describe the climate–vegetation dynamics of the last 4,500 years in the high subtropical Andes of Chile (30°S). The paleoclimatic reconstruction was carried out through the analysis of fossil pollen and macroscopic carbon obtained from sediment cores from two high Andean lakes. The dynamics of the vegetation was analyzed taking into account the alpha and beta diversity. The pollen and carbon records showed three contrasting periods during the last 4,500 years. From the beginning of the sequences until ∼1900 cal. yr BP, relatively dry climatic conditions are suggested, with a slight trend toward more humid conditions after 2,700 cal. yr BP. Pollen records from ∼1900 to ∼600 cal. yr BP suggest wetter conditions than today. Finally, relatively arid conditions have reappeared in the last ∼600 years. The diversity analysis showed that the climate mainly influences the composition of taxa in the communities (beta diversity) and not the richness (alpha diversity). In periods of dry/wet transition and vice versa, beta diversity changes. On the other hand, richness remains relatively constant throughout the record.

Fire and montane vegetation dynamics through successive phases of human occupation in the northern Drakensberg, South Africa

Palaeoecological evidence is compared with the existing archaeological record to understand how changing human activity, over the past two millennia, impacted fire regimes and vegetation dynamics in the Drakensberg Mountains, South Africa. Sediment cores from two wetland sites in the Cathedral Peak area of the northern Drakensberg, KwaZulu-Natal are dated using accelerator mass spectrometry to chronologically support biological proxy data. Fossil pollen analysis is used to detect changes in vegetation composition, and macroscopic charcoal to reconstruct changing fire regimes. Charcoal accumulation rates (CHAR) are used as a proxy for burned biomass, and charcoal width-to-length ratio (W/L) as a proxy for dominant fuel type, whether grassy or woody. Results indicate an increase in CHAR, coincident with the appearance of cereal-type grasses (>40 μm) c. 550 cal BP, suggesting a change in fire regimes associated with the arrival of early agropastoralists. A notable decline in charcoal W/L at this time indicates a shift towards a more grassy fuel type. This is consistent with a seasonal shift in the timing of ignitions from high intensity late season lightning fires to low intensity early season anthropogenic fires. The latter are less damaging to woody vegetation explaining an overall shift to a more grassy fuel type. Large scale ecosystem change is evident in the colonial period, including decreased forest pollen taxa such as Podocarpus, which may be linked to colonial period logging. The increased dominance of Pteridium spores documents the invasion trajectory of bracken fern into montane grasslands in the area, which is attributed to ecosystem disturbance in the form of colonial fire suppression. The subalpine wetland clearly documents woody encroachment of the surrounding open grassland landscape during the agropastoral and subsequent colonial periods. By contrast, at the montane wetland site, these trends appear to be overprinted by local forest dynamics and recent deforestation, likely an elevation effect. Palaeoecological evidence demonstrates how changes in fire regimes and vegetation composition in the northern Drakensberg are closely tied to human activity over the past two millennia.

Evaluation of anthropogenic indicators used in fossil pollen analysis and land-use types

Paleocoğrafya araştırmalarında geçmişteki insan faaliyetleri ve insanın ortam üzerindeki etkilerinin belirlenmesi büyük bir öneme sahiptir. Göl ve bataklık sedimanlarından elde edilen fosil polen verileri arazi üzerindeki insan faaliyetlerinin belirlenmesinde kullanılan en yaygın dolaylı kayıtlardan biridir. Bu çalışmada fosil polen kayıtlarında insan etkisinin yorumlanmasında kullanılan ve belirli arazi kullanım şekillerini yansıtan antropojenik göstergelerin bir arada verilmesi ve bu alandaki araştırmacıların kullanımına sunulması amaçlanmıştır. Bunu gerçekleştirmek için güncel polen ve fosil polen analizi çalışmalarına ait bulgular ve değerlendirmeler ve bunların farklı lokasyonlarda yer alan fosil polen analizi bulgularına uyarlanması esas alınmıştır. Tarihsel süreçte insan faaliyetlerinin farklı şekilleri belirli dönemlerde farklı bitki türlerinin dolayısıyla farklı polen birliklerinin ortaya çıkmasına ya da yayılmasına neden olmuştur. Bu polen birliklerinin fosil polen diyagramlarında kullanılması sonucunda insan etkisi ve bazı arazi kullanım şekilleri belirlenebilmektedir. Şimdiye kadar gerçekleştirilen polen çalışmalarının değerlendirilmesi sonucunda tarım arazileri, terk edilmiş tarım arazileri, otlatma ve tarım faaliyetlerinden etkilenen araziler, doğal ormanların tahrip edildiği araziler olmak üzere dört farklı arazi kullanım şekli ve bu arazileri işaret eden en yaygın antropojenik göstergeler belirlenmiştir.

Improving the taxonomy of fossil pollen using convolutional neural networks and superresolution microscopy

Taxonomic resolution is a major challenge in palynology, largely limiting the ecological and evolutionary interpretations possible with deep-time fossil pollen data. We present an approach for fossil pollen analysis that uses optical superresolution microscopy and machine learning to create a quantitative and higher throughput workflow for producing palynological identifications and hypotheses of biological affinity. We developed three convolutional neural network (CNN) classification models: maximum projection (MPM), multislice (MSM), and fused (FM). We trained the models on the pollen of 16 genera of the legume tribe Amherstieae, and then used these models to constrain the biological classifications of 48 fossil Striatopollis specimens from the Paleocene, Eocene, and Miocene of western Africa and northern South America. All models achieved average accuracies of 83 to 90% in the classification of the extant genera, and the majority of fossil identifications (86%) showed consensus among at least two of the three models. Our fossil identifications support the paleobiogeographic hypothesis that Amherstieae originated in Paleocene Africa and dispersed to South America during the Paleocene-Eocene Thermal Maximum (56 Ma). They also raise the possibility that at least three Amherstieae genera (Crudia, Berlinia, and Anthonotha) may have diverged earlier in the Cenozoic than predicted by molecular phylogenies.

Environmental change and human land‐use over the past 200 years in the Great Hinggan Mountains, Northeastern China

AbstractMountain ecosystems are sensitive to environmental changes and are affected by direct and indirect anthropogenic activities. This study sought to understand the impacts of human occupation, environmental and climate change on the Great Hinggan Mountains (GHM) in Northeastern China. The last 200 years of environmental changes are reconstructed by analyzing sediment cores from five small mountain lakes. Cores were dated using 210Pb and 137Cs radioisotopes, microscopic charcoal identified regional fire activity and fossil pollen analysis reconstructed temporal and spatial changes in vegetation. Peaks in 137Cs, 226Ra and microscopic charcoal flux were found to follow similar trends between sites. The radioisotope records reflect redistribution processes, such as erosion and fire events, which overwhelm the atmospheric fallout signal in the GHM. Microscopic charcoal increased from 1950 CE and peaked at all sites after 2000 CE suggesting that current fire management, coupled with a warmer climate due to global warming, may be leading to more wildfire events in the region. Pinus, Quercus and Betula declined at all sites as human occupation occurred in the early 1900s. Initially, open forest and grassland expanded in response to overexploitation of forests, followed by arboreal pollen reaching maximum values after 2000 CE. This study concludes that the present‐day mixed coniferous broad‐leaved forest dominating the southern region of the GHM is a product of changing fire activity, excessive logging and, more recently, forestry management and vegetation regeneration. Results suggest further management strategies are needed to address land degradation and wildfire events in mountain regions of Northeastern China.

Abrupt mid-Holocene decline in the Indian Summer Monsoon caused by tropical Indian Ocean cooling

The evolution of the Indian Summer Monsoon (ISM) has been widely investigated and traditionally interpreted as consequences of orbital forcing change and the migration of the Intertropical Convergent Zone (ITCZ). The potential influence of sea-surface temperature (SST) on ISM variation at millennial time scales has been progressively proposed in recent studies. Towards a better understanding of Holocene evolution of ISM, especially the potential response to variations in SST, a 643 cm continuous sediment sequence covering the past 11.1 ka was recovered from Beihai Wetland in western Yunnan Plateau. Fossil pollen analysis revealed that evergreen broadleaved forest dominated the regional vegetation in the early Holocene, which represented a warm and humid period associated with strong ISM. Expansions of deciduous broadleaved forest and grassland from 5.2 cal. ka BP to the present, together with the appearance of abundant plant remains, indicate the formation of the wetland system. Ordination analysis of the pollen assemblages further confirmed the abrupt vegetation turnover at ca. 5.2 cal. ka BP, which is consistent with the abrupt decline in reconstructed mean annual precipitation (Pann, from ca. 1400 to 1100 mm), and indicates an abrupt decline in the summer monsoon. We performed a climate regime shift test on various records from the ISM domain and eastern Africa and found this phenomenon as well, which could not be explained by changes in solar insolation or the migration of the ITCZ. A mid-Holocene cooling was detected from the Indian Ocean, especially a decreased SST in the tropical Indian Ocean ca. 5.5 cal. ka BP. Cooling of the tropical Indian Ocean possibly caused the abrupt retreat of the summer monsoon by restraining the duration of the monsoonal season and the convergent process, which was supported by an abrupt monsoon decline based on results from a minimal concept model.

Akgöl’de (Sakarya) Fosil Polen Analizine Dayalı Paleovejetasyon Araştırmaları: İlk Bulgular

Fossil pollen analyzes include research of pollen grains from various environments such as lake sediments, peatland, river and marine sediments, glaciers, lignite and coal. Lakes are one of the important data sources for Quaternary palynological studies. Akgöl, which is selected as a research area, is located in Gölkent district of the Ferizli township in the provincial city of Sakarya. Its surface area is 3.5 km2 and its maximum depth is 8 meters. The aim of this study was to investigate vegetation changes around Akgöl in the last 1000 years using fossil pollen analysis in the bottom sediments of the lake. The Piston corer of ITU EMCOL Research Centre was used for recovering sediment cores from Akgöl. Sediment samples of 2 cm3 were collected every 5 centimeters on one of the cores at the Palynology Laboratory of IUC. Fossil pollen analysis was performed according to the “classical method”. The pollen percentage values were calculated for each plant taxa and relative abundance graphs were plotted in the TILIA program. According to preliminary results of the pollen diagram; deciduous forest vegetation has been predominant in the last 1000 years around Akgöl. Maritime pine was introduced into this natural forest by plantation in the recent years.

Airyscan superresolution microscopy: A high-throughput alternative to electron microscopy for the visualization and analysis of fossil pollen

Airyscan confocal superresolution microscopy is a new optical technique that can detect morphological features smaller than the diffraction limit of light. It captures both the external and internal ornamentation of modern and fossil pollen. Airyscan combines the ease of use of optical microscopy methods, such as confocal and brightfield microscopy (BM), with the high-resolution imaging of electron microscopy (EM). Modern and fossil pollen grains were imaged using Airyscan, BM, and EM to assess the viability of Airyscan as an alternative for EM. Our results demonstrate that: (1) Airyscan can capture diagnostic features of extant and fossil pollen similar to EM; (2) one-to-one comparisons of Airyscan images with other optical methods are possible (e.g., BM and conventional confocal); (3) Airyscan captures three-dimensional data, allowing reconstruction of pollen grains in different views; and (4) the time and effort required for Airyscan imaging is significantly less than that for EM. This paper demonstrates that Airyscan superresolution microscopy is a high-throughput alternative for morphological analyses of pollen specimens.

The Apparent Resilience of the Dry Tropical Forests of the Nicaraguan Region of the Central American Dry Corridor to Variations in Climate Over the Last C. 1200 Years

The Central American Dry Corridor (CADC) is the most densely populated area of the Central American Isthmus and is subject to the greatest variability in precipitation between seasons. The vegetation of this region is composed of Dry Tropical Forests (DTF), which are suggested to be highly susceptible to variations in climate and anthropogenic development. This study examines the vulnerability of past DTF surrounding the Asese peninsula, Nicaragua to climatic and anthropogenic disturbances over the past c. 1200 years. Past vegetation, climate, burning, and animal abundance were reconstructed using proxy analysis of fossil pollen, diatoms, macroscopic charcoal, and Sporormiella. Results from this research suggest that DTF have been highly resilient to past climatic and anthropogenic perturbations. Changes in DTF structure and composition appear to be linked to the abundance and intensity of fire. Pre-Columbian anthropogenic impacts on DTF are not detected in the record; however, DTF taxa decline slightly after European contact (1522 C.E.). Overall the DTF for the Nicaraguan region of the CADC were found to be highly resilient to both climatic and anthropogenic disturbances, suggesting that this region will continue to be resilient in the face of future population expansion and climatic variation.

The Legacy of Pre–Columbian Fire on the Pine–Oak Forests of Upland Guatemala

Mountain tropical forests of the Southern Maya Area (Pacific Chiapas and Guatemala, El Salvador and Northern Honduras) predominantly comprise pine and oak formations, which form intricate mosaics and complex successional interactions following large–scale fire. These forests have been transformed by the peoples of the Maya civilization through practices of horticulture, agriculture and architectural developments over thousands of years. Anthropogenic impacts and the extent of early human interaction with these upland forests is currently poorly understood. In this study we identify: (i) the natural baseline vegetation of the region; (ii) when human impact and agrarian practices began in the Maya uplands; and (iii) what impacts the Maya had on forest structure, composition, and successional regeneration. Past vegetation, anthropogenic use of fire, and faunal abundance were reconstructed using proxy analysis of fossil pollen, macroscopic charcoal, microscopic charcoal, and dung fungal spores (Sporormiella). Three phases of forest succession were identified from 4000B.C.E. to 1522CE that broadly overlap with the well–defined archaeological periods of (i) the Archaic (10,000–2000B.C.E.); (ii) Pre–Classic (2000B.C.E. –100C.E.); (iii) Terminal Pre–Classic (100–250C.E.); (iv) Classic (250–950C.E.); and (v) Post–Classic (950–1522C.E.). These results also include the earliest evidence for agriculture within the Southern Maya Area through presence of peppers (Capsicum) from 3850B.C.E. and the rise of maize cultivation (Zea mays) from 970B.C.E. Persistent high intensity burning driven by agricultural practices and lime production during the Late–Pre-Classic (400–100B.C.E.) to Classic Period resulted in a compositional change of forest structure c.150B.C.E. from oak (Quercus) dominated forests to pine (Pinus) dominated forests. The legacy of Pre–Columbian anthropogenically driven fire in these mountain tropical forests demonstrates the resilience and thresholds for fire driven succession. These findings are particularly relevant for addressing current land use and management strategies involving agriculture, fire, and forest management in the mountain tropical forests of the Southern Maya Area.

Güneybatı Anadolu’dan Yeni Bir Paleoekolojik Değerlendirme: Karataş Gölü ve Çevresinin Geç Holosen Paleovejetasyon Değişimleri ve İklim ile İlişkileri

This study was carried out in Lake Karataş which is located at the site of Burdur Depression in the southwestern Anatolia (Tefenni Plain). The main aim of the study is to determine the changes of paleovegetation and the factors that effect these changes from ̴2000 cal. BP years ago to Lake Karataş and its surroundings. For this purpose, fossil pollen analysis methods were applied on sediment core with a total length of 255 cm. The data obtained were diagrammed in the Tilia 2. 0. 41 program. Pinus sp., Juniperus sp. and Quercus sp. (evergreen) in arboreal pollen (AP) and Chenopodiaceae, Asteraceae, Lactuaceae and Poaceae in nonarboreal pollen (NAP) are important species that forming the vegetation. The temporal changes of these species reveal the local vegetation structure which is effective around the lake. Generally Abies sp., Cedrus libani and Quercus sp. (evergreen) indicate that 1460-1150 cal. BP, 840-680 cal. BP and 680-480 cal. BP are cold periods. In the whole diagram, the peak period of human impact was determined as 840-30 cal. BP. Olea europaea, Vitis sp. Fraxinus sp. in AP and Polygonum aviculare, Plantago lanceolata, Centaurea solstitialis in NAP corresponds to the peak period in the diagram. As a result, depending on the methods of analysis of fossil pollen, as a result of climate change and human impact, the variety of individual plant species constituting the paleovegetation structure and forest progression / regression were evaluated. 

Late Quaternary vegetation, climate, and fire history of the Southeast Atlantic Coastal Plain based on a 30,000-yr multi-proxy record from White Pond, South Carolina, USA

AbstractThe patterns and drivers of late Quaternary vegetation dynamics in the southeastern United States are poorly understood due to low site density, problematic chronologies, and a paucity of independent paleoclimate proxy records. We present a well-dated (15 accelerator mass spectrometry14C dates) 30,000-yr record from White Pond, South Carolina that consists of high-resolution analyses of fossil pollen, macroscopic charcoal, andSporormiellaspores, and an independent paleotemperature reconstruction based on branched glycerol dialkyl tetraethers. Between 30,000 and 20,000 cal yr BP, openPinus-Piceaforest grew under cold and dry conditions; elevatedQuercusbefore 26,000 cal yr BP, however, suggest warmer conditions in the Southeast before the last glacial maximum, possibly corresponding to regionally warmer conditions associated with Heinrich event H2. Warming between 19,700 and 10,400 cal yr BP was accompanied by a transition from conifer-dominated to mesic hardwood forest.Sporormiellaspores were not detected and charcoal was low during the late glacial period, suggesting megaherbivore grazers and fire were not locally important agents of vegetation change.Pinusreturned to dominance during the Holocene, with step-like increases inPinusat 10,400 and 6400 cal yr BP, while charcoal abundance increased tenfold, likely due to increased biomass burning associated with warmer conditions. Low-intensity surface fires increased after 1200 cal yr BP, possibly related to the establishment of the Mississippian culture in the Southeast.

History and conservation of Tunisia's largest freshwater wetland: Garâa Sejenane

The Garâa Sejenane is an ancient lake in northern Tunisia that currently houses a mosaic of temporary wetlands. Comparison of modern pollen data and field vegetation surveys shows both a weak regional pollen signal and the homogenization of pollen assemblages at the scale of the garâa. Despite a hiatus between 19,000 and 2230 cal. BP, fossil pollen analyses provide the first Tunisian LGM record and attest to the ancient origin of the lake, which housed some taxa still present locally in the 1950s. The originality of the Pleniglacial surrounding landscape dominated by a juniper steppe contrasted with the mountain conifer forests in Kroumiria. Lastly, analyses of aerial photographs (1948, 1962, 1984), recent satellite photographs and previous botanical descriptions reveal that the lake has been drying since 1960 because of important anthropogenic activities (drainage, groundwater pumping, cultivation, grazing…). These disturbances have generated profound changes in hydrophytic plant communities (fragmentation, diversity loss, introduction of invasive species…) that are likely to threaten their long-term survival.

Study of modern pollen distribution in the northeastern Indian Ocean and their application to paleoenvironment reconstruction

Learning pollen transport mechanisms is the basis for correct interpretation of fossil pollen data. Firstly, 33 seabed surface sediment samples from the northeastern Indian Ocean were selected for pollen analysis. Utilizing the 90°E Indian Ridge as a dividing line, more Trilete spores (mainly Microlepia)and herbaceous pollen were present to the west or northwest of the line, possibly originating in Sri Lanka and India. More Polypodiaceae spores and tree pollen (Pinus excluded) were present to the east or southeast of the boundary, possibly originating in Sumatra Island. Based on the PCA analysis, the ocean current from the southeast to the northwest and the distance from land masses around the study area affect the percentage of pollen. Then, based on a fossil pollen analysis on the YDY05 core from the northeastern Indian Ocean, we determined that since 16 ka BP, the pollen terrestrial area might change from Sumatra Island to Sri Lanka Island and India, probably due to the climate and sea level change.

Mid-to late-Holocene paleovegetation change in vicinity of Lake Tuzla (Kayseri), Central Anatolia, Turkey

This study carried out in Lake Tuzla in northeast Cappadocia (Central Anatolia- Kayseri-Palas Plain) aimed primarily to determine changes in paleovegetation of mid-to late-Holocene in the vicinity of Lake Tuzla and factors affecting these changes. A secondary objective was to determine paleoenvironmental conditions during the settlement period of Kültepe (Karum-Kanis), an important archaeological site in the region. Fossil pollen analysis was carried out on a sediment core 337 cm long representing the period from the present day extending back to 5080 ± 30 years. Changes in paleoclimatic conditions and paleovegetation were identified. From changes in the vegetation, the climatic changes determined were dry in the periods 3200-3000 BP, 2050–1450 BP, and 1120-850 BP; and humidity in the periods 1400-1115 BP and 1400–1700 BP. Alterations to the vegetation structure between 3230 and 1155 BP reveal the effects of the Beyşehir Occupation Phase (BOP). According to Lake Tuzla data, the effect of BOP was relatively less than that of Lake Nar. After the end of BOP, pine forests grew in the area around Lake Tuzla. The vegetation consisted of Pinus and Quercus in AP (arboreal pollen) and Artemisia, Amaranthaceae and Poaceae in NAP (non-arboreal pollen). The density of Artemisia, Amaranthaceae and Poaceae taxa suggests that steppe vegetation was dominant in the surroundings of Lake Tuzla.

Tracking recent human impacts on a nutrient sensitive Irish lake: integrating landscape to water linkages

High-resolution palaeolimnological analysis was implemented on a sediment core from Lough Muckno, a historically polluted inter-drumlin lake located in northeast Ireland. Focusing on chironomid and fossil pollen analyses, catchment conditions and human impacts on the lake environment during the last c. 200 years are identified and characterized. Chironomid community response to historical land-use change, reconstructed through a combination of pollen analysis and documentary evidence is evaluated in detail. The results provide insights into lake ecological conditions from a meso-eutrophic state in a nineteenth century agricultural setting to a highly eutrophic system in a landscape under modern pastoral management. Increasing livestock numbers and concomitant land fertilization are considered to be the main drivers affecting chironomid assemblages. Redundancy analysis indicates that grassland-based agriculture, inferred from Poaceae (grasses), the dominant component of palynological pastoral indicators, was the main variable controlling chironomid community composition. Lake resilience to nutrient abatement is reflected in a limited chironomid response to declining agricultural activity during the Great Irish Famine (c. 1846) and attempts at point and non-point pollution controls. Integrated interpretation of chironomid, pollen and non-pollen palynomorphs is shown to be a powerful tool for assessing the impacts of modern land-use change on lake ecology through time.