Pollen Index Research Articles

Ecological and allergenic significance of atmospheric pollen spectra from a Grassland-Savanna ecotone in North West province, South Africa

Southern Africa’s floral, topographic and climatic diversity manifests in distinctive bioregions where aerobiology studies are needed to manage allergenic health problems, especially in urban areas. Previous studies underline different seasonal pollen fluctuations for the biomes, encouraging regional studies. These studies have been previously restricted to large cities such as Cape Town, Johannesburg and Pretoria whereas small cities such as Potchefstroom in the North-West province are understudied. The South African Pollen Monitoring Network (SAPNET) seeks to fill this lacuna, enhancing ecological and health-related knowledge, with regard to the allergenicity of the recorded pollen. Here, we investigate plant phenology and resulting pollen production within the Grassland and Savanna biomes around Potchefstroom, a fast-growing city in the North West province, comparing it with other SAPNET sites. As a SAPNET initiative, pollen monitoring in Potchefstroom involved monthly collections using a Lanzoni 7-day spore trap over 13 months from December 2022 to 2023. This facilitated the development of a preliminary pollen calendar and a pollen atlas, detailing pollen types’ morphology, ecology, pollination modes, and allergenicity. Initial findings revealed Potchefstroom’s pollen calendar, with tree pollen (60% of the Annual Pollen Index (API)) mainly from northern hemisphere species such as Cupressus (c. 11% of API) and Platanus (c. 18%), which released pollen in spring. Grass pollen was predominant from November to April (c. 18% of API). Potchefstroom recorded South Africa’s highest levels of Ambrosia pollen (c. 7% of API), a major allergen, in March and April. Noteworthy is the unusual abundance of pollen of the neophyte Ulmus (c. 14%) in December. This study highlights the pollen patterns of the Grassland and Savanna biomes around Potchefstroom. The region, with its mosaic of urban spaces, natural grass-/woodland, and agricultural land, exhibits distinct characteristics when contrasted with major, more densely populated cities such as Bloemfontein, Pretoria, and Johannesburg.

A second Artemisia pollen peak in autumn in Vienna: reaching the point of no return?

AbstractThe Artemisia (mugwort) pollen season usually ranges from July until September, with one peak period around mid-August in Vienna (Austria). During the last decade, Artemisia pollen was also recorded later in September. This pattern was concluded by a significant peak pollen concentration day in autumn of 2023, which exceeded the usual summer peak pollen concentration day. The Artemisia pollen data from Vienna for the last ten years (2014–2023) were therefore analysed for a temporal trend. In addition, weather data from Vienna (temperature, precipitation, and relative humidity and sun hours) were retrieved and analysed to find a possible association with Artemisia pollen indices. No significant trend could be observed regarding the Artemisia pollen season parameters and no correlation was found between the weather data and the Artemisia pollen integrals during summertime. However, a significant positive correlation was found between higher temperatures during autumn and the occurrence of Artemisia pollen during this time. This suggests that a significant change in the Artemisia pollen season can be expected during years with a mild, summer-like autumn. Until now, it is not clear which species of Artemisia cause the pollination in autumn. A. annua and A. verlotiorum are two major suspects that could have established themselves in Vienna, but further evidence is needed. Considering the impact of global climate change, the shift in the pollen season for Artemisia described in this study could represent a point of no return.

Temporal trends of seasonal pollen indexes in a region of Northern Italy (2001–2022)

Increasing trends in allergic respiratory diseases may be linked to climate changes affecting pollen levels. This study aimed to investigate the temporal trends in seasonal indexes of 9 allergenic pollen types in the Veneto Region, Northern Italy. Available daily data from 20 monitoring stations covered 2001–2022 for Corylaceae, Cupressaceae, Poaceae, Oleaceae, and Urticaceae (pollen families), and 2006–2022 for Alnus, Betula, Ambrosia, and Artemisia (pollen genera). The 95-percentage method was used to identify the start/end dates of pollen seasons annually, and the seasonal cumulative pollen concentration (Seasonal Pollen Integral, SPIn) was calculated. The non-parametric Theil-Sen median slope method was used to examine trends in pollen seasons’ start day, duration, and SPIn in the whole region and for climatic areas (alpine, subcontinental eastern, subcontinental western). The results showed a clear upward trend in SPIn for several pollens, with median slopes ranging from 326 (Alnus) to 1089 p/m3 per 10yrs (Corylaceae); exceptions were Artemisia, whose SPIn decreased over time (−26 p/m3 per 10yrs), and Ambrosia, Betula, and Urticaceae, which did not show a clear trend. For families, pollen seasons showed a trend for anticipation (from −4.7, Urticaceae, to −13.5 days/10yrs, Oleaceae) and extended duration (from 8.3, Cupressaceae, to 13.3 days/10yrs, Oleaceae). An evident heterogeneity across the climatic areas was seen for the SPIn, with the subcontinental western area exhibiting the highest loads and most prominent increases over time. In conclusion, increased levels and prolonged seasons for several pollen taxa observed in the Veneto Region, particularly in subcontinental areas, suggest increasing risks for individuals with pollen allergies. Addressing this issue requires measures of mitigation and adaptation to climate-driven changes in pollen exposure.

Amaranthaceae Pollen Trends in the Air

Understanding the trends of airborne pollen allergens is of great importance given the high prevalence and socioeconomic impact of pollen-related allergic diseases globally. To study the morphological features of Amaranthaceae pollen, assess its contribution to the aerobiological situation in the city of Karakol and identify periods of increased concentration in order to improve the diagnosis and prevention of pollinosis symptoms in patients. Aerobiological sampling using a Lanzoni pollen trap was carried out from April to October over a three-year period (2015–2017) in Karakol city. Pollen identification and differential counting were performed according to current standard methodology and specially developed guides and atlases. Pollen characteristics of 4 Amaranthaceae species were visualized using scanning electron microscopy (Hitachi) to provide a detailed understanding of the surface structure and ornamentation of pollen grains. The decadal curve of Amaranthaceae pollen concentration in Karakol is unimodal, with often overlapping quantitative characteristics: 6615 (2nd decade of August 2015), 1326 (1st decade of 2016), 444 pollen grains / m3 (1st decade of 2017). At the same time, strong interannual variability of atmospheric pollen levels was observed, depending both on the pollen production of the plants themselves and on meteorological parameters, especially temperature and precipitation, changes in the traditional farming system. The response of summer-flowering Amaranthaceae weeds to climate change was demonstrated, which consists in a decrease in the annual pollen index, which corresponds to the global trend. Peak concentrations of Amaranthaceae pollen many times exceeded clinical threshold values in the air. On the surface of the Bassia scopariapollen exine, the ultrastructure study revealed the smallest (1.5-2.0 μm) granules of sporopollenin or orbicules (Ubisch bodies), which play a role in the spread of allergens. The obtained data are important in terms of increasing public awareness of the dominant pollen of the Amaranthaceae family, optimizing diagnostics, treatment and prevention of pollinosis.

Pollen- and Weather-Based Machine Learning Models for Estimating Regional Olive Production

The olive tree is one of the most common type of cultivation in the Mediterranean area, having high economic and social importance. The Alentejo region, Portugal, is an area with a high presence of olive groves, which in 2022 accounted for 201,474 hectares. The aim of this study was to assess the relationship between olive pollen, weather data, and olive tree production, between the years 2002 and 2022. Pollen data were obtained from an urban station located in Évora, in the Alentejo region, and were used to calculate several metrics, such as the Pollen Season Duration (PSD), Seasonal Pollen Index (SPIn), peak value, and weekly pollen accumulation values. Monthly minimum, maximum, and mean temperature and precipitation sums were obtained from the E-OBS observational dataset. Considering the relationship between pollen/weather and olive production, mutual information and correlation analyses were conducted. Subsequently, several machine learning algorithms were trained using pollen and weather datasets, and we obtained suitable forecast models for olive tree production after cross-validation. The results showed high variability in pollen concentrations in Évora over the years. Complex associations were found, with certain weeks of pollen accumulation showing significant mutual information with olive production, particularly during June. The analyzed linear correlation coefficients remained generally low, underscoring the challenge of predicting olive production based on linear relationships. Among the machine learning algorithms employed to predict olive production, Decision Trees, Extreme Gradient Boosting, and Gradient Boosting Regressor were the most robust performers (r2 > 0.70), while linear models displayed a subpar performance (r2 < 0.5), emphasizing the complexity of this approach. These models highlight the roles of maximum and minimum temperatures during March and May and pollen accumulation during the second half of June. The developed models may be used as decision-support tools by growers and stakeholders to further enhance the sustainability of the thriving olive sector in southern Portugal.

Influence of inputs from foreign source regions on daily profiles of Olea pollen at an urban site in the southeast of the Iberian Peninsula

The daily cycle of pollen concentrations reflects its genetic response to environmental conditions. The detailed study of these cycles was used to identify the influence of external sources on local pollen levels. In this work, three different daily profiles (Ci) of Olea pollen concentrations were identified in the city of Alicante (southeastern Spain) using cluster analysis. For this, 2-h data from 2010 to 2015 were used. The percentage frequency, pollen index and mean Olea pollen concentration (in pollen grains∙m−3) for each cluster were: C1 (∼91%, 8797, 26), C2 (∼7%, 4641,179) and C3 (∼2%, 1845, 308). C1 was the predominant pattern throughout the whole MPS, while C2 and C3 were only present in the middle of the MPS. Small variations in pollen concentrations throughout the day were observed for C1, while C2 and C3 showed the highest pollen concentration at ∼04:00 UTC and 10:00 UTC, respectively. C1 represented concentration patterns due to local pollen inputs, being influenced by precipitation events, sea breezes and the recirculation of air pollutants. On the other hand, C2 and C3 were strongly influenced by external pollen inputs from southwestern regions of Spain. The results of this study indicate that external inputs from these regions were associated with exposure of the population to high pollen concentrations for short periods of time. In contrast, inputs from the northwest were associated with exposure to lower pollen concentrations for longer periods of time.

Subalpine peatland development since the Last Glacial Maximum in subtropical China: Predominantly controlled by monsoonal climate and local topography

Peatlands interact significantly with the global carbon cycle and climate changes. A comprehensive understanding of the development of peatlands is extremely important to help address future climate challenges. Here, we combine three total organic carbon content records with seven published records from subalpine peatlands in the monsoonal region of subtropical China, aiming to reveal the general pattern of peatland development since the Last Glacial Maximum (LGM) in this region. The synthesis showed that organic carbon contents significantly increased at approximately 16 cal kyr B.P. These ten records clearly display two distinct patterns since that time: pattern one showed three intervals of high carbon contents at ca. 16−12 cal kyr B.P., 9.5−7.5 cal kyr B.P. and 6−4 (or 4−1) cal kyr B.P., whereas pattern two reached the maximum in the early Holocene and remained high and relatively stable during the Holocene. Through comparison with pollen indicators and climate reconstructions, we demonstrated that local hydrology linked to monsoonal climates (especially precipitation) was the dominant factor controlling carbon accumulation and the development of subalpine peatlands since the LGM in subtropical China. However, two dynamic patterns that occurred under the same climatic conditions were attributed to the significant modulation of local topography, i.e., intermontane basin (pattern one) or montane (pattern two) settings. The hydrology and development of peatlands are functions of the changes in monsoonal climate and local site-specific topography. These findings provide a comprehensive understanding of past long-term development of peatlands under monsoonal climates.

The Establishment of the Agricultural Landscape of Central Sicily Between the Middle Neolithic and the Beginning of the Iron Age

The possible co-variation of human occupation and vegetation from the Middle Neolithic to the beginning of the Iron Age (7.5–2.8 ka BP) in Central Sicily in the context of the central Mediterranean between Middle and Late Holocene are analysed in this paper to provide new insights on Sicilian prehistoric demography. The demographic and economic trends during these millennia were reconstructed using archaeological, Accelerator Mass Spectrometry 14C dates, palynological, archaeobotanical, and zooarchaeological data from the northern, central, and southern sectors of Central Sicily through a diachronic comparison with variation in Arboreal Pollen, Anthropogenic Pollen Indicators, Olea-Juglans-Castanea pollen, microcharcoals, and Sporormiella from four pollen cores from sites in different ecosystems. A very significant spread of farming activities was found at the end of the Neolithic, together with an apparent demographic gap during the Middle Copper Age, and the emergence of agricultural landscapes at the end of the Copper Age associated with a striking increase in population. A combination of cultural and climatic changes during the late phase of the Bronze Age resulted in a subsequent overall decrease in population.

The evolution of river systems under the influence of climate change and human activities in the endorheic zones during the Holocene

Endorheic river basins and their terminal lakes are highly sensitive to climate change and human activities. Based on chemical and pollen indicators, lake level, and erosion/accumulation rates of rivers, we explore the phasing of the evolution of the river system in the Hexi Corridor during the Holocene. The results suggest that climate change dominated the evolution of the river system during the early-Mid-Holocene. Entering the historical period, humans began to have an impact on runoff, water resources, and lake evolution, and since 1000 BP, anthropogenic perturbations recorded by regional proxies increased and humans dominated the migrations of river . In addition, we discuss the widespread erosion of rivers in the global endorheic zone and the impact of human activities in this context and found the timing of human influence on river evolution is not the same in different regions.

Pollen indices of Cedrus atlantica Manetti populations vary with geographical localities in the Moroccan Atlas Mountains

North Africa’s forests of Cedrus atlantica Manetti have declined drastically, by more than 58% in the last 130 years, and many stands are likely to disappear entirely in the coming decades. This study on the interactions between C. atlantica pollen characters (production, germination, and pollen tube length) and locality characters in Morocco, using seventy individuals from seven geographically distant populations, showed that pollen indices varied according to station. Pollen production was high in the populations of the Moudemam-1 and Seheb stations, intermediate in the Ait Oufella and Ait Ayach stations, and low in the Zerrouka, Ras Elma and Moudemam-2 stations. Pollen germination was very low for the populations in the Seheb and Moudemam-1 stations but high in the other stations. On the other hand, the longest pollen tubes were recorded in the Moudemam-1 population, while those in the other stations were shorter. These results show an inverse variation between the pollen indices characterizing the populations of the stations studied. The shortest pollen tube length classes [0-100] to [300-400] accounted for 85.98% of all classes and were assessed for the Zerrouka, Ait Oufella and Ait Ayach stations. The other classes were more represented or exclusive to the population of the Moudemam-1 station. These results could have implications not only for assessing pollen variations according to geographical localities but also for optimizing fertilization in cedar forests by selecting the best clones for this species.

Vegetation and climate of southern Siberia in the Late Holocene at decadal resolution: a multiproxy study of the Lake Shira lacustrine sediments, Minusa Basin

New AMS14C-dated records of changes in the natural environment of southern Siberia from varve sediments of Lake Shira (Minusinsk Basin) are presented. The results allow reconstructing the history of vegetation, biomes, climate, relative productivity of the lake system, changes in the lake catchment erosion, and water levels in the lake itself over the past 2980 cal. years with an average temporal resolution of 21 years. The new reconstructions indicate a wet regional climate between 2980 and 2650 cal yr BP and its gradual aridization later. At the same time, the climate of the basin itself was more arid, thus providing the development of steppe and meadow-steppe communities around the lake in the last 2980 years. Variations in the Artemisia/Chenopodiaceae pollen ratio, considered as an indicator of moisture available to plants, suggest a slight increase in the moisture level in the Minusa Basin from 2980 to 50 cal yr BP and its noticeable decrease in the last 50 years. Reconstructions show that changes in vegetation around Lake Shira in the Late Holocene were mainly caused by large-scale circulation processes that changed the regional moisture balance. Steppe vegetation turned out to be very sensitive to moisture changes on a decadal scale. No clear pollen indicators of anthropogenic impact on vegetation were found in the new pollen record.

Environmental evolution of the south shore of Kandalaksha Bay, as indicated by the study of bottom sediments from small lakes

Environmental changes on the south shore of Kandalaksha Bay in Holocene time were reconstructed by analyzing the data obtained by palynological and 14C methods. Diatom complexes of marine, freshwater and transition facies are described. The possible application of pollen indicators for a better understanding of the genesis of sediments is discussed.

Nettle pollen - an important taxon of the summer pollen flora of Polish urban areas in the 2023 season

New significant clinical studies suggest the enormous preventive and therapeutic capabilities of Urtica dioica L. Despite being already known as multi-purpose plant, it is still underestimated and relatively poorly researched in regards to its allergenic potential. The aim of the study was to compare nettle pollen season in 2023 in ten cities located in different regions of Poland: Bialystok, Kraków, Kielce, Lublin, Olsztyn, Piotrków Trybunalski, Szczecin, Warszawa, Wrocław and Łódź. Nettle pollen grains were collected using Burkard or Lanzoni Hirst-type volumetric samplers. The 95% method was used to determine the duration of the pollen seasons. The nettle pollen season in 2023 began in June. The earliest onset of the pollen season was recorded in Kielce (June 15th), in Wrocław (June 16th) and Warszawa (June 17th). In most of the monitored cites maximum daily pollen concentrations were registered in the middle of September. Mean seasonal pollen index (SPI) reached the value of 8579. The highest total values (SPI) were in Lublin (14,387) in Kielce (13,424) and in Wrocław (12,304). The lowest total values level (SPI) was in Białystok (3434) and in Łódź (4935). But in Łódź in October 2023, thanks to favourable weather, many Urtica dioica L. plants bloomed again. Unfortunately, aerobiological research was no longer carried out at that time.

Ash pollen season in selected Polish cities in 2023

According to some authors, ash pollen has strong allergenic properties. In Europe the allergenic significance of this pollen has been poorly studied as the amounts of ash pollen in the air are low. However, in Poland we are more and more often observing ash pollen seasons with the total annual pollen sum exceeding 1000 grains. In 2023, it was found in Cracow and Łódź. This study compares the ash pollen seasons in Bialystok, Bydgoszcz, Cracow, Kielce, Piotrkow Trybunalski, Opole, Olsztyn, Szczecin, Lodz, Wroclaw, Zielona Gora, Warsaw and Lublin in 2023. The investigations were carried out using the volumetric method (Hirst type pollen sampler). Seasonal pollen index (SPI) was estimated as the sum of daily average pollen concentrations in the given season. The ash pollination is mainly observed in April. Diagnosis of ash pollen allergy is made difficult due to an overlapping pollination period with Betulaceae and some cross-reactivity with allergens from birch, and even privet and olive. It is not clear whether ash pollen is a primary cause of sensitization or whether it is implicated through cross-sensitization to other pollens. In 2023 the pollen season of ash started first in Kielce and Opole, on the March 11th and 13th. At the latest, a pollen season ended in Bialystok, on the May 12th. The differences of pollen seasons duration were very considerable, from 23 to 57 days. The highest airborne concentration of 530 (!) pollen grains/m3 was noted in Cracow on the April 3rd. The peak values of seasonal pollen count in Polish cities occurred between April 3rd and 24th, most often between April 17th and 24th. The highest ash pollen allergen hazard occurred in 2023 in Cracow and Lodz, and was at least 2–3 times higher than in other cities. The highest variability in the analysed seasons was found in the peak value and annual total.

The South African Pollen Monitoring Network: Insights from 2years of national aerospora sampling (2019-2021).

Pollen monitoring has been discontinuously undertaken in South Africa, a country with high biodiversity, a seasonal rainfall gradient, and nine biomes from arid to subtropical. The South African Pollen Monitoring Network was set up in 2019 to conduct the first long-term national aerospora monitoring across multiple biomes, providing weekly reports to allergy sufferers and healthcare providers. Daily airborne pollen concentrations were measured from August 2019 to August 2021 in seven cities across South Africa. Updated pollen calendars were created for the major pollen types (>3%), the average Annual Pollen Index over 12 months was calculated, and the results were compared to available historical data. The main pollen types were from exotic vegetation. The most abundant taxa were Poaceae, Cupressaceae, Moraceae and Buddleja. The pollen season start, peak and end varied widely according to the biome and suite of pollen taxa. The main tree season started in the last week of August, peaked in September and ended in early December. Grass seasons followed rainfall patterns: September-January and January-April for summer and winter rainfall areas, respectively. Major urban centres, for example, Johannesburg and Pretoria in the same biome with similar rainfall, showed substantive differences in pollen taxa and abundance. Some major differences in pollen spectra were detected compared with historical data. However, we are cognisant that we are describing only 2years of data that may be skewed by short-term weather patterns. Differences in pollen spectra and concentrations were noted across biomes and between geographically close urban centres. Comparison with historical data suggests pollen spectra and seasons may be changing due to anthropogenic climate change and landscaping. These data stress the importance of regional and continuous pollen monitoring for informed care of pollinosis.

Anthropogenic pollen indicators: Global food plants and Latin American human indicators in the pollen record

Pollen-based evidence of human presence is crucial for reconstructing human history. However, information on the morphology of pollen grains of global food plants and regional pollen-based human indicators is scattered in the literature, leading to the risk of overlooking important evidence of human presence. To address this issue, we first compiled a comprehensive overview of 354 major food plants worldwide, creating a paleoecology-friendly format that includes their family, vernacular name, earliest known use, environmental preference, and geographical region. Moreover, we identified the sources of illustrations of their pollen grains for 209 out of 273 different genera of globally relevant food plants in 10 selected pollen atlases. Secondly, we compiled all human indicators from pollen-based paleoecological literature in Latin America (based on 750 references), providing an overview of 212 single-pollen type indicators and identified 95 crucial combinations of pollen types as “human indices”, and their corresponding references. Our review datasets aids in distilling human evidence from numerous fossil pollen records worldwide.

BIOMETRIC INDICES OF POLLEN FROM NATURAL POPULATIONS OF <i>PINUS BRUTIA</i> VAR. <i>PITYUSA</i> (PINACEAE) OF THE CRIMEAN MOUNTAINS

The study of biometric characteristics of Pinus brutia var. pityusa pollen was carried out in natural populations of P. brutia var. pityusa in the Crimean Mountains. The pollen was collected during the period of its free flight on sample plots along four hypsometric profiles. In the western part of the southern macroslope of the Main Ridge of the Crimean Mountains on Cape Aya in the Ayazma tract, 3 sample plots were laid at altitudes of 50–290 m above sea level, in Batiliman – 2 plots, at altitudes of 50 and 120 m above sea level; in the eastern part of the macroslope, 3 plots were laid on Karaul-Oba Mt. at altitudes of 40–120 m above sea level, and in the Novyy Svet tract – 2 plots at 50 and 100 m above sea level. Biometric analysis of pollen grains was carried out on temporary acetocarmine slides using generally accepted methods. The results of the study showed that an average size of the pollen grain of P. brutia var. pityusa in natural populations of the Crimean Mountains varies within the following ranges: total grain length from 81.5 to 88.5 μm, the length and height of the pollen grain body 52.2–59.4 μm and 47.8–53.4 μm, respectively, and the length and height of the air sac 40.0–43.0 μm and 25.5–30.4 μm, respectively. The smallest pollen is formed in coastal stands. In the plantations of P. brutia var. pityusa in the western part of the Crimean Mountains, a decrease in the length and height of the air sacs was noted. It was revealed that the indices characterizing the ratio of individual structural elements of the pollen grain, namely γ – the ratio of the body length to the height of the air sac of the pollen grain, δ – the ratio of the body height to the height of the air sac, and Θ – the ratio of the body length to the length of the air sac, allow to analyze aerodynamic properties of P. brutia var. pityusa pollen. The decrease in γ, δ, and Θ pollen indices in the plantations of Ayazma and Batiliman reflects a decrease in the efficiency of its aerial distribution, which has a negative effect on the level of heterogeneity of natural populations in these territories.

The vertical distribution of modern pollen in the southeastern edge of the Tibetan Plateau, China

The tropical mountainous area of the southeastern Tibetan Plateau (TP) is a hotspot of ecological environment research because of its rich biodiversity. However, limited knowledge regarding modern pollen rain within this area has impeded further investigation of eco-environmental evolution using the pollen record. We collected 62 modern pollen samples from lowland tropics to the subalpine region (740–3550 m a.s.l.) in Medog County, located in the southeastern TP, and performed pollen analysis. Cluster analysis, redundancy analysis, variance partitioning analysis, and boosted regression trees were employed to investigate the relationship between pollen and vegetation/climate. Additionally, Hill numbers (N0, N1, N2) and specificity–occupancy plots were utilized to explore plant diversity. The results indicate that modern pollen rain in Medog reflects well the current characteristics of the vegetation, encompassing both primary and secondary features. Pollen of Cyclobalanopsis, Tsuga and Abies, which are dominant components of the primary vegetation above 2100 m a.s.l., can serve as indicator species for paleovegetation reconstructions. Mean annual precipitation is the most important climatic determinant affecting pollen distribution. Pollen indices reveal that the plant diversity in this study area has a bimodal pattern of ‘relatively high–low–highest–low’ with increasing altitude. The plant diversity above 2100 m a.s.l. is mainly decided by primary vegetation, whereas below 2100 m a.s.l. it can be explained by the intermediate disturbance hypothesis. Furthermore, it is advisable to exercise caution when dealing with arboreal pollen evenness in open mountainous environments due to the increased potential pollen source area caused by valley wind.

Paleoecological data complete historical and archaeological archives: Human–environment nexus at the fluvio maritime city port of Chilia (Licostomo; Northern Danube delta) since the 14th century

AbstractThis study reconstructs the paleoecological settings of Chilia/Licostomo, the most important Genoese colony in the Danube delta. Our paleoenvironmental data (i.e., sedimentology, pollen, charcoal, radiocarbon ages) corroborate historical and archaeological information over the last seven centuries to document the habitation at Chilia and its military and socioeconomic activity during ca. 14th–19th centuries A.D. Palynological data show the continuous presence of humans, with anthropogenic pollen index calculation (API) values between 2% and 16% during the last five centuries. The variability of API, corroborated with the major peaks of the charcoal concentration, matches the documented military conflicts and population changes in the area: the Ottoman conquest of Dobrugea (15th century A.D.), the Zaporozhians Cossaks raids (17th century A.D.), and the Russian–Ottoman wars (18th–19th centuries A.D.). The presence of coprophilous fungi fits the Ottoman tradition of animal husbandry, whereas their appearance after the Zaporozhians Cossacks raids and their good correlation with open land vegetation suggest that the Chilia loess island was temporally used as a refuge from multiple menaces (e.g., wars, administrative crisis). These paleoecological data, together with the rare archaeological findings, exclude human habitation of the Chilia Plain earlier than the documented arrival of the Lipovans during the late 18th century A.D. The critical assessment of the correspondences between the paleoecological and historical data shows the relevance of the approach in deltaic environments, when applied to lagoon/lacustrine sediments, yet often limited to chronologically disparate, decennial‐ to multicentennial‐scale temporal frameworks.

Rapid vegetation responses over the last seven decades revealed by an alpine ice core and land-cover patterns

ContextSyntheses of vegetation responses over the last century are rare for the Alps, and limited in chronological and taxonomical resolution. We propose that pollen records from glaciers can be used to fill this gap.ObjectivesOur aim is to evaluate the reliability of glacier pollen records as historical archives of biodiversity to obtain plant diversity data and landscape changes. In detail, we aim at reconstructing taxa and vegetation trends in central sector of the Italian Alps over the last century integrating pollen-inferred vegetation trends with drifts in spatially explicit land-cover.MethodsOur study area is the Lombardy region (Italy). We performed pollen analyses of Adamello glacier cores, and reconstructed trends of single taxa and main vegetation types since the 1950s. Pollen-inferred vegetation trends were calculated using pollen indicators obtained from a database of vegetation-plot observations. The reliability of these trends is evaluated by comparison with spatially explicit tendencies reconstructed with a time-series of land-cover maps.ResultsPollen records well represent the natural vegetation types as the temperate and the riverine forests, and the anthropic vegetation as crops and alien species. From the 1980s a thermophilisation took place, and warm-demanding native and alien species expanded. The contraction of cultivated land since the 1970s, and the decline of the riverine forest appear driven by socio-economic factors.ConclusionsWe conclude that pollen-inferred vegetation trends from glaciers can be used to obtain large scale biodiversity information. This is relevant also for areas where biodiversity data are scarce but needed for landscape management planning.