We studied a 2200-year-old sediment core from Lake Zapovednoye, a small, deep, freshwater lake near the site of the 1908 Tunguska impact event. Analysis of the sediment core for geochemistry, pollen, chironomids, Cladocera, and diatoms revealed traces of climatic fluctuations during the investigated time period during which a cool climate before 1000 CE was replaced by the Medieval Climatic Optimum, the Little Ice Age, and finally the modern warming. An increased content of terrigenous elements was identified at the depth corresponding to ca. 1908 CE. This layer presumably resulted from erosion of the soil cover after the tree fall caused by the Tunguska impact event (the largest recorded in history). For the first time, the reaction of lake biota to an impact event has been detected. Our study has demonstrated that the taxonomic diversity of hydrobionts (chironomids and cladocerans) significantly declined after the catastrophe, probably due to increased turbidity, and recovered in 6–10 years. The pollen and diatom assemblages, however, demonstrated weaker compositional shifts.

Written accounts suggest there were major changes in agricultural practices in Anatolia as the region switched between Roman, Byzantine, Arab and Turkic control, yet archaeological evidence of these changes is offered only on a site-by-site basis. This article presents the first synthesis of archaeobotanical, palynological and zooarchaeological evidence for changes in plant and animal husbandry in Anatolia through the first and second millennia AD. Available data indicate a minimal role of climate change in agricultural shifts but offer evidence for substantial changes towards short-term-return agricultural strategies in response to declining personal security, changing patterns of military provisioning and distinct taxation regimes.

The generalist predatory mite, Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae) is one of the most effective biocontrol agents to control the pests of many crops in indoor cultivations. In this study, the effects of the enriched diets of the second trophic level, i.e. the stored-product mite, Tyrophagus putrescentiae (Schrank) on the performance of N. cucumeris as the third trophic level was determined in a tritrophic system. In the first step, different pollens including almond, maize, date palm, castor bean, saffron, and cattail or different legume flours including pinto bean, lentil, black-eyed pea, chickpea, mung bean and broad bean as enrichment additives were added to the basic diet, i.e. a mixture of wheat bran and flour as a basic diet of T. putrescentiae. In the second step, to reveal the effects of the mentioned additives on the performance of N. cucumeris, the demographic parameters of the predator were determined when it was fed with the prey enriched with the additives. Our results indicated that N. cucumeris had higher performance by feeding on the prey reared on diets enriched by either pollens or legumes compared with the basic diet. Overall, there was no significant difference between pollen grains and some legume flours when the predatory mite was fed with them through its prey. Since legumes are more available and cost-effective food sources than pollens, they can be affordable supplementary diets for the mass rearing of N. cucumeris.

To investigate long-term relationships between climate, vegetation, landscape geochemistry and fires in the boreal forest zone of Western Siberia, a sediment core of 345 cm was collected from Shchuchye Lake (located in south taiga zone of southeast part of West Siberian plain) and investigated by spore-pollen, radiocarbon, LOI and charcoal analyses. Quantitative palaeoclimate was reconstructed based on pollen data. Investigation revealed 13.2 cal ka history of vegetation, climate, landscapes and fires. In the dry climate of Late Glacial, the landscape was treeless. Continuous permafrost existed in the soil. In the middle of the YD cooling 12.4–12.2 cal ka BP, our data showed warming that caused degradation of permafrost in soils and settlement of spruce in moist places. Later, thawing and accumulation of moisture in a local lowering in relief increased and a lake was formed. With the beginning of the Holocene, the climate sharply changed to warmer and wetter. Intensified surface flow caused accumulation of mineral and carbonate fraction in the lake. Dense birch forests spread on drylands. As a result, the leaching regime initiated the formation of podzols in the soil. At about 10.0 cal ka BP, Scots pine (Pinus sylvestris) quickly spread in the area of investigation. Fires became more frequent and more intense during the dry Late Glacial time, sharply decreasing with increased precipitation in the Early Holocene, and again moderately increasing with spread of pine forests in the mid Holocene. With the transition to Late Holocene (after 6.0 cal ka BP), the intensity of regional background fires and number of local fires decreased.

From the 1990s, the Southeast Asia native giant resin bee Megachile sculpturalis (Smith, 1853) was introduced first to North America, and then to many countries in Europe. Despite increasing studies on its invasive potential and geographical expansion, information on nesting behaviour of this species is still extremely scarce. To increase knowledge on the nesting biology of M. sculpturalis, we studied multiple aspects of nesting and pollen provisioning in three consecutive years in artificial nests in Bologna, Italy. We observed 166 bees visiting nests, and followed individual nesting behaviour and success of 41 adult females. We measured cavity diameter in 552 nests and characterised the structure in 100 of them. More than 95% of nest diameters ranged between 0.6 and 1.2 cm, overlapping with several sympatric species of cavity-nesting hymenopterans in the study area. Most nests had a first chamber from the entrance of variable length without brood, followed by an average of about two brood cells with a mean length of 2.85 ± 0.13 cm each. The pollen stored in brood cells was almost monofloral, belonging to the ornamental plant Styphnolobium japonicum (L.) Schott. We estimated that a single female should visit ≈180 flowers to collect enough pollen for a single brood cell. These results fill knowledge gaps on the nesting biology and nest structure of the exotic M. sculpturalis, and they are discussed in relation to possible competition with native bees for nesting sites and foraging resources.

Connecting changes in erosion and vegetation is necessary for predicting topographic and ecologic change in thawing permafrost landscapes. Formerly periglacial landscapes serve as potential analogs for understanding modern permafrost landscape change, yet compared to paleoenvironmental records at these sites, less is known about concurrent geomorphic processes, particularly their rates and relationships to climate change. Here, we target sediments preserved in a central Appalachian peat bog to reconstruct sedimentation across the last deglacial warming. We use ground-penetrating radar and geochemistry of cored bog sediments to quantify sedimentation timing, style, and provenance. Using 14C dating of sedimentary and geochemical shifts, we connect depositional changes to global climate and local vegetation change. We show that deglacial warming promoted deep soil disturbances via solifluction at ca. 14 ka. In contrast, relatively wetter conditions from ca. 10–9 ka promoted shallow disturbance of hillslopes via slopewash, which corresponds to a time of vegetation change. Our results highlight climate-modulated erosion depth and processes in periglacial and post-periglacial landscapes. The existence of similar erosion and vegetation records preserved regionally implies these dynamics were pervasive across unglaciated Appalachian highlands, aiding in reconstructing erosion responses to warming at a resolution with implications for predicting high-latitude landscape responses to disturbance.

The Paisley Cave archeological site in the Northern Great Basin has provided a rich archaeological record from 13,000 to 6000 cal yr BP, including abundant mammalian coprolites preserved in a well-dated stratigraphy. Here we analyze and contrast pollen from within coprolites and pollen in associated sediments to examine vegetation history and assess whether coprolite pollen provides unique information with respect to the coprolite producer, such as the use of specific habitats, foods, or water sources. We found that the dissimilarity of pollen assemblages between coprolites and associated sediments was greater than the serial dissimilarity between stratigraphically adjacent samples within either group. Serial dissimilarity within types was not greater for coprolites than sediments, as would be expected if there were unique pollen signatures derived from the short period (1–2 days) represented by each coprolite. Compared with sediment pollen assemblages, the coprolites had higher abundances of lighter pollen types, and some individual samples were high in wetland taxa (especially Typha). Our results are consistent with coprolite pollen representing short time periods collected as a mammal moves on the landscape, whereas sediment pollen reflects longer time periods and more regional vegetation indicators.

Arid regions are especially vulnerable to climate change and land use. More than one-third of Earth's population relies on these ecosystems. Modern observations lack the temporal depth to determine vegetation responses to climate and human activity, but paleoecological and archaeological records can be used to investigate these relationships. Decreasing rainfall across the Late Holocene provides a case study for vegetation response to changing hydroclimate. Rock hyrax (Procavia capensis) middens preserve paleoenvironmental indicators in arid environments where traditional archives are unavailable. Pollen from modern middens collected in Dhofar, Oman, demonstrates the reliability of this archive. Pollen, stable isotope (δ13C, δ15N), and microcharcoal data from fossil middens reveal changes in vegetation, relative moisture, and fire from 4000 cal yr BP to the present. Trees limited to moister areas (e.g., Terminalia) today existed farther inland at ~3100 cal yr BP. After ~2900 cal yr BP, taxa with more xeric affiliations (e.g., Senegalia) had increased. Coprophilous fungal spores (Sporormiella) and grazing indicator pollen revealed an amplified signal of domesticate grazing at ~1000 cal yr BP. This indicates that trees associated with semiarid environments were maintained in the interior desert during ~3000–4000 yr of decreasing rainfall and that impacts of human activity intensified after the transition to a drier environment.

As the main global terrestrial ecosystem component, grasslands are extremely sensitive to global climate change. With increasing human activities over the last century, grassland ecosystems have been degraded to different degrees. However, the evolution of lake-grassland ecosystems in recent centuries remains unclear due to the dearth of high-resolution records. Here, we present high-resolution lacustrine sediment grain size, pollen (Artemisia, Myriophyllum), Pediastrum, and n-alkane records from Ganggeng Nur Lake to investigate vegetation, lake evolution, and human effects in semiarid northern China. Four stages were identified from the last ca. 150 years: (1) the natural evolution stage (AD 1870–1945), in which there was a wet climate around Ganggeng Nur and the lake level rose from increased runoff; (2) the human disturbance stage (AD 1945–1967), in which the regional climate got drier and human activities began having a detectable effect on the grassland ecosystem; (3) the human transformation stage (AD 1967–2005), in which a completely arid climate coupled with the implementation of a series of land reclamation policies resulted in a large reduction in grassland areas, extensive soil erosion, exacerbated climate change, and shrinking lake areas; and (4) the posttreatment stage (AD 2005–2018), in which soil erosion was alleviated by policy implementation and a favorable humid climate.

This paper presents the first continuous multi-proxy record of climate and vegetation change from the central Namib Desert extending over much of the last ca. 39,000 years. Derived from rock hyrax middens, evidence from stable carbon and nitrogen isotopes, pollen, and microcharcoal reveals significant differences between glacial-age and Holocene climates and vegetation types. Although still arid to semi-arid, conditions during Marine Oxygen Isotope Stages (MIS) 2–3 were significantly more humid than in the Late Holocene. Considerable associated vegetation change is apparent, with cooler temperatures and higher/more-regular rainfall promoting the westward expansion of relatively mesic shrubby karroid vegetation during MIS 2–3. With the last glacial–interglacial transition, increasing temperatures and less/less-regular rainfall resulted in marked vegetation changes and the establishment of current xeric grasslands. The inter-plant spacing of the karroid vegetation promoted by wetter conditions does not carry fire effectively, and the microcharcoal record indicates that more extensive fires may develop only with the development of grassier vegetation under drier conditions. As with other terrestrial records from the Namib Desert and environs, no Cape flora elements were found to support previously hypothesised expansion of the Fynbos Biome during the last glacial period.

A 13.0 cal ka BP pollen record from Twin Ponds, Vermont, provides new insights into the climate history of the northeastern United States. Modern analogs were used to produce qualitative and quantitative climate reconstructions for Twin Ponds. The Twin Ponds record was compared with nearby Knob Hill Pond to develop a Vermont reconstruction that was compared with reconstructions from two sites at a similar latitude. Postglacial warming at 11.5 cal ka BP followed a cool, wet Younger Dryas and was the largest temperature change of the record. The warmest, driest conditions occurred at ca. 9.0 cal ka BP, followed by an increase in moisture. Latitudinal and elevational shifts in the location of modern analogs from 5.7 to 4.0 cal ka BP were used to infer cooling and increased moisture during the Tsuga canadensis decline. Analysis of the timing of pollen events between the two Vermont sites suggests a more rapid decline in T. canadensis at the more northern Knob Hill Pond and further supports the possibility that colder temperatures contributed to this event. The other northern sites show similar trends until 2.5 cal ka BP, when precipitation in the easternmost site diverges, indicating the establishment of modern climatic gradients.

Pollen preserved in caves provides a little-appreciated opportunity to study past vegetation and climate changes in regions where conventional wetland sediments are either unavailable, contain little organic matter, and/or are difficult to date accurately. Most palynology in caves has focused on clastic infill sediments, but pollen preserved in growing speleothems provides important new opportunities to develop vegetation and climatic records that can be dated accurately with radiometric methods. However, when pollen is present in speleothems, concentrations can vary by orders of magnitude, highlighting how little we know about the processes that transport pollen into caves and onto speleothem surfaces, and that determine the pollen's preservation probability. To explore these aspects of speleothem pollen taphonomy, we investigated the distribution of pollen and microscopic charcoal within several stalagmites from southwest Australia. We examined spatial patterns in pollen and charcoal preservation in order to distinguish whether observed gradients result from preservation or are products of systematic transport processes working along stalagmite surfaces. We find that pollen grains and charcoal fragments are located preferentially on the flanks of most stalagmites. This suggests that pollen grain and charcoal deposition on speleothems is influenced by transport and accumulation of detrital debris on growing surfaces. These insights will assist in future sampling campaigns focusing on speleothem pollen and charcoal contents.

A robust understanding of the impact of anthropogenic activities on high-altitude tropical aquatic ecosystems is key for the conservation and protection of the Tropical Andean biodiversity hot spot. We present the results of a multiproxy study of lake sediments from the high Andean páramo of El Cajas National Park, a UNESCO biosphere reserve in Ecuador. The main site, Laguna Pallcacocha, is well known for recording El Niño–driven clastic flood layers that are triggered by high-intensity rainfall anomalies from the eastern Pacific. The second site, Laguna El Ocho, does not contain clastic laminations, providing a control. The records show abrupt shifts in diatom assemblages ca. AD 1991 in both high-elevation Andean lakes accompanied by local changes in páramo composition that suggest a sudden nutrient enrichment of the environment. The diatom assemblages from Laguna Pallcacocha, in relation to the clastic input events, are remarkably stable and do not show evident El Niño signals at the analysed resolution. Based on comparison with the nonlaminated El Ocho record, we deduce the main source of this nutrient enrichment to be the construction of a heavily transited road that runs through the park, while climate warming played secondary role by amplifying its effects.

Terracing is found widely in the Mediterranean and in other hilly and mountainous regions of the world. Yet while archaeological attention to these ‘mundane’ landscape features has grown, they remain understudied, particularly in Northern Europe. Here, the authors present a multidisciplinary study of terraces in the Breamish Valley, Northumberland. The results date their construction to the Early to Middle Bronze Age, when they were built by cutting back the hillside, stone clearance and wall construction. Environmental evidence points to their use for cereal cultivation. The authors suggest that the construction and use of these terraces formed part of an Early to Middle Bronze Age agricultural intensification, which may have been both demographically and culturally driven.

Single-cell analysis is important to understand how individual cells work and respond at the cell population level. Experimental single-cell isolation techniques, including dilution, fluorescence-activated cell sorting, microfluidics, and micromanipulation, have been developed in recent decades. However, such applications typically require large cell populations and skilled professionals. Additionally, these methods are unsuitable for sequential analysis before and after cell isolation. In this study, we propose a method for target cell isolation using automated infrared laser-mediated disruption of pollen grains in pollen populations. Germination of the target pollen was observed at the same location as that before laser irradiation, and germinated pollen grains were enriched in the cell population. Pollination of laser-irradiated bulk pollen populations also showed that the target pollen preferentially germinated on the stigma. This method is expected to facilitate physiological analyses of target cells at the single-cell level and effectively produce seeds derived from target pollen.

Despite extensive paleoenvironmental research on the postglacial history of the Kenai Peninsula, Alaska, uncertainties remain regarding the region's deglaciation, vegetation development, and past hydroclimate. To elucidate this complex environmental history, we present new proxy datasets from Hidden and Kelly lakes, located in the eastern Kenai lowlands at the foot of the Kenai Mountains, including sedimentological properties (magnetic susceptibility, organic matter, grain size, and biogenic silica), pollen and macrofossils, diatom assemblages, and diatom oxygen isotopes. We use a simple hydrologic and isotope mass balance model to constrain interpretations of the diatom oxygen isotope data. Results reveal that glacier ice retreated from Hidden Lake's headwaters by ca. 13.1 cal ka BP, and that groundwater was an important component of Kelly Lake's hydrologic budget in the Early Holocene. As the forest developed and the climate became wetter in the Middle to Late Holocene, Kelly Lake reached or exceeded its modern level. In the last ca. 75 years, rising temperature caused rapid changes in biogenic silica content and diatom oxygen isotope values. Our findings demonstrate the utility of mass balance modeling to constrain interpretations of paleolimnologic oxygen isotope data, and that groundwater can exert a strong influence on lake water isotopes, potentially confounding interpretations of regional climate.

Wally Broecker’s puzzles required radiocarbon dating in order to solve them.

Pollen and diatom assemblages from well-dated sediment cores from three lakes forming a west-to-east transect across the boreal forest in northwest Ontario (Canada) were used to evaluate the timing and nature of the movement of the prairie–forest ecotone (PFE) across the Holocene. Changes in vegetation, temperature, and effective moisture were inferred from pollen and pollen-based transfer functions. Analyses indicated site-specific vegetational and climate changes across short spatial distances, with prolonged prairie-like conditions during the middle Holocene at the westernmost site. Increased reconstructed temperatures at this westernmost site occurred from ~9000 to 3000 cal yr BP, alongside increases in diatom-inferred lake levels beginning at ~6000 cal yr BP. The abundance of Quercus peaked concurrently with rising lake levels before declining to trace levels by ~3000 cal yr BP. Increases in the abundance of non-arboreal pollen between ~8500 and ~4500 cal yr BP at the more eastern lakes suggest relatively delayed and truncated PFE influence, before the reestablishment of primarily boreal taxa by ~4500 cal yr BP, coincident with diatom-inferred increases in lake levels. This study shows that the PFE moved both farther east and north than previously determined, but generally agrees with established patterns in vegetation from other studied regions along the PFE.

Climate changes over the past two millennia in the central part of the Gulf of St. Lawrence are documented in this paper with the aim of determining and understanding the natural climate variability and the impact of anthropogenic forcing at a regional scale. The palynological content (dinocysts, pollen, and spores) of the composite marine sediment core MSM46-03 collected in the Laurentian Channel was used to reconstruct oceanographic and climatic changes with a multidecadal temporal resolution. Sea-surface conditions, including summer salinity and temperature, sea-ice cover, and primary productivity, were reconstructed from dinocyst assemblages. Results revealed a remarkable cooling trend of about 4°C after 1230 cal yr BP (720 CE) and a culmination with a cold pulse dated to 170–40 cal yr BP (1780–1910 CE), which likely corresponds to the regional signal of the Little Ice Age. This cold interval was followed by a rapid warming of about 3°C. In the pollen assemblages, the decrease of Pinus abundance over the past 1700 yr suggests changes in wind regimes, likely resulting from increased southerly incursions of cold and dry Arctic air masses into southeastern Canada.