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1.
J Evol Biol ; 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39167704

RESUMO

Glacial periods have been considered inhospitable environments that consisted of treeless vegetation at higher latitudes. The fossil record suggests many species survived the Last Glacial Maximum (LGM) within refugia, usually at lower latitudes. However, phylogeographic studies have given support to the existence of previously unknown high-latitude refugia not detected in the fossil record. Here we test the hypothesis that cold-tolerant trees of Patagonia survived cold periods in microclimatically favourable locales where hybridisation occurred between sister taxa. To study local presence through glacial periods in multiple refugia we used pollen records and genetic information (isozymes, microsatellites, and combined nuclear and chloroplast DNA sequences) of population pairs of Nothofagus antarctica and N. pumilio, that belong to the ancient subgenus Nothofagus which can potentially hybridize in nature, along their entire latitudinal range in Patagonia. Studied species share the N. dombeyi type pollen which was abundant >20% at the northern-most latitudinal bands (35-43°S), even during the LGM. Mid- and southern latitudinal records (44-55°S) yielded lower abundances of ~10% that increased after c. 15.0 cal. ka BP. Therefore, fossil pollen evidence suggests a long-lasting local presence of Nothofagus throughout glacial-interglacial cycles but mostly as small populations between 44-51°S. We found species-specific and shared genetic variants, the latter of which attained relatively high frequencies thus providing evidence of ancestral polymorphisms. Populations of each species were similarly diverse suggesting survival throughout the latitudinal range. Estimates of coalescent divergence times were broadly synchronous across latitudes suggesting that regional climates similarly affected populations and species that hybridized through climate cycles fostering local persistence.

2.
Sci Total Environ ; 949: 174986, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-39053556

RESUMO

The importance of understanding the long-lasting legacy of past land use on modern ecosystems has long been acknowledged. However, the magnitude and persistence of such legacies have been assessed only occasionally. Northern Greece has been a gateway of farming into mainland Europe during the Neolithic, thus providing a perfect setting to assess the potential impact of land-use history on present-day ecosystems. Additionally, the marked Holocene climatic variability of the southern Balkans makes it possible to investigate climate-vegetation-land use interactions over long timescales. Here, we have studied a sediment record from Limni Vegoritis (Northern Greece) spanning the past ∼9000 years using palaeoecological proxies (pollen, spores, stomata, microscopic charcoal). We aimed to reconstruct long-term vegetation dynamics in submediterranean Greece, to assess the environmental factors controlling them and to establish the legacies of the long history of land use in the modern landscape. We found that the Early Holocene afforestation, mainly oak woodlands, was delayed because of suboptimal moisture conditions. Later, colder and drier conditions during the rapid climate change centred around the '8.2 ka event' triggered woodland opening and the spread of wooded (Juniperus) steppe vegetation. First indicators of farming activities are recorded during this period, but their abundances are too low to explain the concurrent large deforestation episode. Later, pinewoods (probably dominated by Pinus nigra) with deciduous Quercus spread and dominated the landscape for several millennia. These forests experienced repeated multi-centennial setback-recovery episodes associated with land-use intensification, but pines eventually declined ∼2500-2000 years ago during Classical times under heavy land use comprising intense pastoralism. This was the starting point for the present-day landscape, where the main 'foundation' taxon of the ancient forests (Pinus cf. nigra) is missing, therefore attesting to the strong imprint that historical land use has left on the modern landscape.


Assuntos
Agricultura , Mudança Climática , Ecossistema , Grécia , Florestas , Monitoramento Ambiental , Conservação dos Recursos Naturais
3.
New Phytol ; 243(2): 797-810, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38807290

RESUMO

Automated pollen analysis is not yet efficient on environmental samples containing many pollen taxa and debris, which are typical in most pollen-based studies. Contrary to classification, detection remains overlooked although it is the first step from which errors can propagate. Here, we investigated a simple but efficient method to automate pollen detection for environmental samples, optimizing workload and performance. We applied the YOLOv5 algorithm on samples containing debris and c. 40 Mediterranean plant taxa, designed and tested several strategies for annotation, and analyzed variation in detection errors. About 5% of pollen grains were left undetected, while 5% of debris were falsely detected as pollen. Undetected pollen was mainly in poor-quality images, or of rare and irregular morphology. Pollen detection remained effective when applied to samples never seen by the algorithm, and was not improved by spending time to provide taxonomic details. Pollen detection of a single model taxon reduced annotation workload, but was only efficient for morphologically differentiated taxa. We offer guidelines to plant scientists to analyze automatically any pollen sample, providing sound criteria to apply for detection while using common and user-friendly tools. Our method contributes to enhance the efficiency and replicability of pollen-based studies.


Assuntos
Algoritmos , Pólen , Automação , Meio Ambiente , Processamento de Imagem Assistida por Computador/métodos
4.
Front Plant Sci ; 15: 1348182, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38571712

RESUMO

Pollen analysis, a crucial tool in botany and ecology for examining historical biotic dynamics, has elicited debate owing to its complex link with vegetation. The challenge lies in discerning the ecological significance of pollen data. In this study, we conducted detailed quadrat surveys on Jinhua Mountain, subtropical China, analyzing topsoil pollen to determine whether pollen signals accurately reflect key ecological components in the forests and shrublands. We performed direct comparisons between pollen and plant compositions and calculated pollen percentages and plant Important Values (IVs) for each quadrat. The results indicate greater homogeneity in pollen composition across the study area compared to plant composition, particularly in the high percentage of Pinus pollen. However, distinct plant communities exhibited significantly different pollen compositions, as evidenced by the multi-response permutation test. This divergence aligns with variations in the dominant plant species across different communities. There were significant correlations between pollen percentages and plant IVs, with correlation coefficients of 0.55 (p < 0.001) at the quadrat level and 0.78 (p < 0.001) at the taxon level. These results support the utility of pollen analysis for representing ecologically significant values in subtropical Chinese forests and shrublands. Such correlations might also be extrapolated to pollen-based paleoecological studies.

5.
Antibiotics (Basel) ; 13(3)2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38534665

RESUMO

Although the plants of the genus Euphorbia are largely exploited by therapists in Morocco, the composition and antibacterial activities of propolis from these plants are still unknown. To address this gap, this study aimed to characterize the pollen type, the volatile compounds, and the phenolic and mineral profiles of three Euphorbia propolis samples collected in Morocco and evaluate their antimicrobial activities. The minimum inhibitory concentration of the propolis samples was determined by the microdilution method, and the anti-adherence activity was evaluated by the crystal violet assay. The examination of anti-quorum-sensing proprieties was performed using the biosensor Chromobacterium violaceum CV026. Pollen analysis revealed that Euphorbia resinifera pollen dominated in the P1 sample (58%), while E. officinarum pollen dominated in the P2 and P3 samples (44%). The volatile compounds were primarily composed of monoterpene hydrocarbons, constituting 35% in P1 and 31% in P2, with α-pinene being the major component in both cases, at 16% in P1 and 15% in P2. Calcium (Ca) was the predominant mineral element in both E. resinifera (P1) and E. officinarum (P2 and P3) propolis samples. Higher levels of phenols, flavonoids and dihydroflavonoids were detected in the E. officinarum P2 sample. The minimum inhibitory concentration (MIC) value ranged from 50 to 450 µL/mL against Gram-positive and Gram-negative bacteria. Euphorbia propolis displayed the ability to inhibit quorum sensing in the biosensor C. violaceum CV026 and disrupted bacterial biofilm formation, including that of resistant bacterial pathogens. In summary, the current study evidences the potential use of E. officinarum propolis (P2 and P3) to combat important features of resistant pathogenic bacteria, such as quorum sensing and biofilm formation.

6.
Insects ; 13(8)2022 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-36005369

RESUMO

Ornamental nursery plants are both a major agricultural industry in the U.S. and a major feature of the urban and suburban landscape. Interest in their relationship with pollinators is two-fold: the extent to which they provide a nutritional benefit to pollinators, and the extent to which they have the potential to harm pollinators by exposing them to pesticide residues in nectar and pollen. We identified plant genera as sources of trapped pollen collected by honey bee colonies located at commercial ornamental plant nurseries in Connecticut in 2015 and 2018 and quantified the percentage of pollen volume collected from each genus for each weekly sample over two seasons. Plant genera grown at these nurseries, particularly Rosa, Rhus, and Ilex, contributed substantially to pollen volume during weeks 23-27 of the year. Among the genera not grown in nurseries, Toxicodendron was also important during weeks 23 and 24, and Trifolium was important in both frequency and quantity throughout the season. Zea was a major component of pollen volume from weeks 28-36 in both sites, even though cropland was not over 11% of land cover at either site.

7.
Front Nutr ; 9: 941463, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35811948

RESUMO

This study presents a detailed characterization of 27 honey samples from the Tara Mountain region in Serbia using different comprehensive techniques and methods. The types of the honey samples were defined as monofloral (4 samples), honeydew (5 samples) and polyfloral (18 samples) honey based on determined polyphenol content, antioxidant activity, electrical conductivity and melissopalynological analyses. Physicochemical parameters such as pH (4.13-4.94), diastase activity (24.20-41.70 DN), acidity (14.60-29.70 meq/kg), content of 5-(hydroxymethyl)furfural (in range below 5, up to 16.90 mg/kg), sucrose (0.20-3.90 g/100 g), and moisture content (15.01-19.23%) confirmed the required quality of the honey samples. Sensory analysis revealed honey characteristics favorable to consumers. Analyses of 19 phenolic compounds using ultra-high-performance liquid chromatography with a diode-array detection and triple quadrupole mass spectrometry (UHPLC-DAD-MS/MS) revealed six phenolic acids and 13 other compounds from the group of flavonoids and their glycosides. In all the samples the highest content was determined for p-coumaric acid, followed by caffeic acid and pinocembrin. Besides total phenolic content and radical scavenging activity, antimicrobial activity was also examined. Most honey samples showed bactericidal activity against Staphylococcus aureus and bacteriostatic activity against Escherichia coli, while none of the honey samples inhibited the growth of Candida albicans. Chemometric analyses were applied for an in-depth study of the results to further evaluate the characteristics of the honey samples studied. Principal component analysis (PCA) was used for assessing the differences in physicochemical parameters, polyphenols content and antioxidant capacity between honey samples. The unrooted cluster tree was used to group the samples based on the melissopalynological analyses.

8.
J Hist Biol ; 55(3): 465-493, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35637366

RESUMO

This article examines how geologists, botanists, and ecologists used pollen as a proxy for past climates in the first half of the twentieth century. It focuses on a particular challenge of measuring climate with pollen: pollen's mobility. As scientists came to learn, pollen from some vegetation is more mobile than others. Pollen's differential mobility challenged regional climatic conclusions because of the potential mixing of pollen from various locations. To minimize the effects of this problem, pollen analysts sought to decrease the noise produced by highly local or foreign pollen. Yet, many ground-truthing and calibration methods were not available to pollen analysts because of the temporal separation between the observer and the object of interest. Instead, pollen analysts had to make spatial meaning out of fossil pollen using empirical studies of modern pollen, inferences from macrofossils and successional history, and applying statistical theories to fossil pollen data. Many of these corrections factors relied on pollen analysts' knowledge of place, including elements like the location's topography, prevailing winds, and plant cover. These elements were a natural part of vegetation-pollen-climate interactions. Scientists needed to account for them to turn pollen into a proxy for climate. Pollen's movement was equally natural, but scientists decided to eliminate some pollen to augment the regional climate signal. These selective eliminations of place suggest that not all elements of place are equally important. Scientists had to omit some elements of place to make sense of the complexities of the natural world.


Assuntos
Fósseis , Pólen , Plantas
9.
Veg Hist Archaeobot ; 31(2): 155-170, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35273429

RESUMO

Observing natural vegetation dynamics over the entire Holocene is difficult in Central Europe, due to pervasive and increasing human disturbance since the Neolithic. One strategy to minimize this limitation is to select a study site in an area that is marginal for agricultural activity. Here, we present a new sediment record from Lake Svityaz in northwestern Ukraine. We have reconstructed regional and local vegetation and fire dynamics since the Late Glacial using pollen, spores, macrofossils and charcoal. Boreal forest composed of Pinus sylvestris and Betula with continental Larix decidua and Pinus cembra established in the region around 13,450 cal bp, replacing an open, steppic landscape. The first temperate tree to expand was Ulmus at 11,800 cal bp, followed by Quercus, Fraxinus excelsior, Tilia and Corylus ca. 1,000 years later. Fire activity was highest during the Early Holocene, when summer solar insolation reached its maximum. Carpinus betulus and Fagus sylvatica established at ca. 6,000 cal bp, coinciding with the first indicators of agricultural activity in the region and a transient climatic shift to cooler and moister conditions. Human impact on the vegetation remained initially very low, only increasing during the Bronze Age, at ca. 3,400 cal bp. Large-scale forest openings and the establishment of the present-day cultural landscape occurred only during the past 500 years. The persistence of highly diverse mixed forest under absent or low anthropogenic disturbance until the Early Middle Ages corroborates the role of human impact in the impoverishment of temperate forests elsewhere in Central Europe. The preservation or reestablishment of such diverse forests may mitigate future climate change impacts, specifically by lowering fire risk under warmer and drier conditions. Supplementary Information: The online version contains supplementary material available at 10.1007/s00334-021-00844-z.

10.
Curr Res Food Sci ; 5: 506-514, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35281336

RESUMO

This study reports on the analysis of eleven Jarrah (Eucalyptus marginata) honeys, of which nearly half (n = 5) were re-classified as Blackbutt (E. patens) honey on the grounds of the predominant flower pollen identified by melissopalynology. Based on a comprehensive analysis of the honeys' physico- and phytochemical characteristics and antioxidant activity data, taking into account pH, electrical conductivity, refractive index and Brix values as well as moisture content, individual fructose and glucose content and derived fructose to glucose ratio alongside total phenolic content and antioxidant activity determined by the DPPH assay, no statistically significant difference was found amongst the eleven honeys classified by pollen analysis into two honey groups, 'Jarrah' or 'Blackbutt'. This study therefore draws into question the value of melissopalynology as an analysis tool to authenticate Jarrah honey.

11.
Plants (Basel) ; 11(6)2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35336674

RESUMO

The goldenrod (Solidago) species are flowering plants that produce nectar and can be the sources of unifloral honeys. S. canadensis and S. gigantea are native to North America and invasive in several European countries, while S. virgaurea is native to Europe. The aim of this work was to determine and compare the antioxidant capacity of goldenrod honeys collected in three central European countries (Hungary, Poland, and Slovakia), from three locations within each country. The botanical origin of each honey sample was checked with melissopalynological analysis. Color intensity was determined using the Pfund scale. The antioxidant activity was determined with different spectrophotometric methods (DPPH, ABTS, and FRAP). The content of total polyphenols, flavonoids, and phenolic acids was quantified using spectrophotometric methods. The highest radical-scavenging activity was identified for Hungarian samples with all three antioxidant capacity assays. Medium antioxidant activity was described for Slovak samples. The DPPH and ABTS assays discriminated Polish honeys with the lowest antioxidant activity. The highest flavonoid and phenolic acid content was detected in Hungarian and Slovak honeys, while the lowest values were measured in Polish samples. Our study shows that the antioxidant capacity of unifloral goldenrod honeys can be different in various countries of origin, correlating with color intensity and polyphenol content.

12.
Food Chem ; 383: 132460, 2022 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-35182878

RESUMO

Proton-nuclear-magnetic-resonance-spectroscopy (1H NMR) is the widely accepted reference method for monitoring honey adulteration; however, the need to find cheaper, faster, and more environmentally friendly methodologies makes the voltammetric-electronic-tongue (VET) a good alternative. The present study aims to demonstrate the ability of VET (in comparison with 1H NMR) to predict the adulteration of honey with syrups. Samples of monofloral honeys (citrus, sunflower and heather, assessed by pollen analysis) simulating different levels of adulteration by adding syrups (barley, rice and corn) from 2.5 to 40% (w/w) were analyzed using both techniques. According to the indicators (slope, intercept, regression coefficient-R2, root mean square error of prediction-RMSEP) of the partial-least-squares (PLS) regression models, in general terms, the performance of these models obtained by both techniques was good, with an average error lower than 5% in both cases. These results support the use of VET as a screening technique to easily detect honey adulteration with syrups.


Assuntos
Mel , Nariz Eletrônico , Contaminação de Alimentos/análise , Mel/análise , Análise dos Mínimos Quadrados , Espectroscopia de Ressonância Magnética/métodos , Pólen
13.
Ecol Evol ; 11(20): 14088-14100, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34707842

RESUMO

In the Aleutian Islands during the Holocene, terrestrial predators were actually absent; as a result, large seabird colonies thrived along the coasts or across entire islands. Bird guano enriches the soil with nitrogen, which can lead to the formation of highly modified ornithogenic (bird-formed) ecosystems. For a more detailed investigation of avian influence, we reconstructed more than 10,000-year-old vegetation dynamics of the coast of Shemya Island (Near Islands) by pollen analysis. At the initial stages of vegetation development (10,000-4,600 cal year BP), sedge-heather tundra grew in the studied area. A seabird colony existed on Shemya from 4,600 to 2,400 cal year BP according to stable isotope analysis. During a period of at least 2,200 years, nitrogen enrichment led to the development of ornithogenic herb meadows with a high presence of Apiaceae. A long-term increase in δ15N above 9-10‰ led to radical shifts in vegetation. Noticeable reduction of seabird colonies due to human hunting led to grass-meadows spreading. After a prolonged decrease δ15N below 9-10‰ (2,400 cal year BP to present), there was a shift toward less productive sedge-tundra communities. However, the significant enrichment of guano affected only the coastal vegetation and did not alter the inland Shemya Island.

14.
J Environ Sci Health B ; 56(7): 685-694, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34264805

RESUMO

This article presents the determination of eight pyrrolizidine alkaloids (PAs) by LC-MS/MS in honeys, pollen, and Senecio brasiliensis (Asteraceae) samples, all from Santa Catarina state, Brazil. In addition, the Box-Behnken design was used to perform an optimized sample preparation on pollens and S. brasiliensis parts. Senecionine and its N-oxide, besides retrorsine N-oxide, were determined in six of the seven honeys samples. Pollen from species of the Asteraceae, Fabaceae, and Boraginaceae families were found with greater predominance in three of the seven honeys samples. In these three honeys samples were also found the highest PAs levels. In beehive pollen, flower, and leaf of S. brasiliensis, the total levels of PAs and their N-oxides reached 221, 14.1 × 104, and 14.8 × 104 mg kg-1, respectively. In honeys, these compounds are chemical contaminants and therefore undesirable when the sum exceeds 71 µg kg-1, according to EFSA. On the other hand, although PAs are naturally present in plant and pollen of some species (Senecio, Crotalaria, Bacharis, Ecchium, Mimosa scabrella, Vernonia), it is important to monitor their levels in plants but also in honeys, and other beehive products since these compounds are transferred to the final product.


Assuntos
Mel , Alcaloides de Pirrolizidina , Senécio , Cromatografia Líquida , Contaminação de Alimentos/análise , Mel/análise , Humanos , Pólen/química , Alcaloides de Pirrolizidina/análise , Espectrometria de Massas em Tandem
15.
J Anim Ecol ; 90(10): 2421-2430, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34096055

RESUMO

Bumble bees (Bombus) are a group of eusocial bees with a strongly generalised feeding pattern, collecting pollen from many different botanical families. Though predominantly generalists, some bumble bee species seem to have restricted dietary choices. It is unclear whether restricted diets in bumble bees are inherent or a function of local conditions due to a lack of data for many species across different regions. The objective of this study was to determine whether bumble bee species displayed specific patterns of pollen collection, and whether patterns were influenced by phylogenetic relatedness or tongue length, a trait known to be associated with structuring floral visitation. Bumble bee pollen collection patterns were quantified from 4,132 pollen loads taken from 58 bumble bee species, representing 24% of the pollen-collecting diversity of this genus. Phylogenetic trait mapping showed a conserved pattern of dietary dissimilarity across species, but not for dietary breadth. Dietary dissimilarity was driven by collection of Fabaceae, with the most similar species collecting around 50%-60% of their diet from this botanical family. The proportion of the diet collected from Fabaceae also showed a conserved phylogenetic signal. Greater collection of Fabaceae was associated with longer tongue lengths, with shorter tongued species focusing on alternative botanical families. However, this result was largely driven by phylogenetic relatedness, not tongue length per se. These results demonstrate that, though generalists, bumble bees are still subject to dietary restrictions that constrain their foraging choices. These dietary constraints have implications for their persistence should their core resources decline in abundance.


Assuntos
Dieta , Pólen , Animais , Abelhas , Filogenia
16.
Biology (Basel) ; 10(4)2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33918149

RESUMO

Although most flowering plants are polyploid, little is known of how the meiotic process evolves after polyploidisation to stabilise and preserve fertility. On wheat polyploidisation, the major meiotic gene ZIP4 on chromosome 3B duplicated onto 5B and diverged (TaZIP4-B2). TaZIP4-B2 was recently shown to promote homologous pairing, synapsis and crossover, and suppress homoeologous crossover. We therefore suspected that these meiotic stabilising effects could be important for preserving wheat fertility. A CRISPR Tazip4-B2 mutant was exploited to assess the contribution of the 5B duplicated ZIP4 copy in maintaining pollen viability and grain setting. Analysis demonstrated abnormalities in 56% of meiocytes in the Tazip4-B2 mutant, with micronuclei in 50% of tetrads, reduced size in 48% of pollen grains and a near 50% reduction in grain number. Further studies showed that most of the reduced grain number occurred when Tazip4-B2 mutant plants were pollinated with the less viable Tazip4-B2 mutant pollen rather than with wild type pollen, suggesting that the stabilising effect of TaZIP4-B2 on meiosis has a greater consequence in subsequent male, rather than female gametogenesis. These studies reveal the extraordinary value of the wheat chromosome 5B TaZIP4-B2 duplication to agriculture and human nutrition. Future studies should further investigate the role of TaZIP4-B2 on female fertility and assess whether different TaZIP4-B2 alleles exhibit variable effects on meiotic stabilisation and/or resistance to temperature change.

17.
Archaeol Anthropol Sci ; 13(3): 42, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33643472

RESUMO

Analyses of high-resolution pollen data, coprophilous fungal spores, microscopic charcoal and sedimentology, combined with radiocarbon dating, allow the assessment of the impact of Sami and Nordic land use in the region surrounding the winter market town of Lycksele in northern Sweden. Such winter markets were established by the Crown during the seventeenth century AD to control the semi-nomadic movements of the Sami who traded here with Finnish settlers and were also taxed and educated. Little is known about Sami and Nordic co-existence beyond these market places, mainly due to a lack of archaeological evidence relating to Sami activity. Vegetation and land-use changes in the region between ~ AD 250 and 1825 reveal no signal for pre-seventeenth century agricultural activity, but the coprophilous fungal spore records suggest the increased regional presence of grazing herbivores (possibly reindeer) between ~ AD 800 and 1100. Sami activity in the parish of Lycksele has been suggested by rich metal finds dated to ~ AD 1000-1350 and they may have been attracted by an abundance of reindeer.

18.
J Hum Evol ; 152: 102948, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33529839

RESUMO

The relationship between the environment and human activities during Marine Isotope Stage (MIS) 4 is important for understanding the origins of modern humans (Homo sapiens) in East Asia, an area where various hypotheses of human origins have been vigorously debated over the past three decades. Unfortunately, only a handful of Paleolithic sites date to MIS 4 in East Asia, hampering our understanding of how environmental changes affected human activities during this time period. Here, we used stratigraphic correlation analysis and optically stimulated luminescence to date the Loufangzi site, an important Paleolithic site in North China that has had an unreliable chronology. Pollen analysis, grain size, and magnetic susceptibility were also used to reconstruct environmental conditions at the Loufangzi site area. Our results show that (1) the age of the upper culture layer of the Loufangzi site is bracketed between ∼70 ka and ∼60 ka and dates to MIS 4 and (2) the regional vegetation from MIS 5 to MIS 4 to MIS 3 was mainly dominated by forest steppe, desert steppe/desert, and steppe, respectively, indicating harsh environmental conditions during MIS 4. Combined with the discovery of Mousterian-like scrapers in the upper culture layer of MIS 4, our results challenge the view that the area was unsuitable for human survival during the Last Glacial period and instead suggest that humans used new technologies to increase their resilience to the cooling climate.


Assuntos
Meio Ambiente , Datação Radiométrica , Animais , Arqueologia , China , Clima , Fósseis , Hominidae
19.
Bull Entomol Res ; 111(1): 73-81, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32515317

RESUMO

The permeability of the crop surroundings to pests and the landscape structure can influence pest dispersal between crop patches as well as its abundance within the crop. In this work, we analyzed the dispersal of the olive moth Prays oleae (Bernard) throughout the olive grove surroundings and their abundance within the crop following three approaches: (i) pollen grains settled on bodies of olive moths collected in olive groves were identified and compared with flora occurring on the surrounding patches; (ii) the capability of P. oleae males to penetrate non-crop patches was analyzed (iii) the effect of the landscape structure on the abundance of the three generations of the olive moth was studied. Pollen grains of scrubs and other trees occurring in the crop surroundings, such as Cistus sp., Quercus sp., Juniperus-type or Pinaceae were identified on P. oleae bodies suggesting that P. oleae penetrates into non-crop habitats. Additionally, woody and, to a lesser degree, herbaceous patches, did not constitute barriers for P. oleae. Finally, more complex and heterogeneous patches presented lower numbers of captures of P. oleae. These results give new insights into the movements of the olive moth in the olive grove surroundings and suggest that the management of non-crop areas could influence this pest abundance.


Assuntos
Distribuição Animal , Produtos Agrícolas , Meio Ambiente , Mariposas/fisiologia , Animais , Produtos Agrícolas/crescimento & desenvolvimento , Masculino , Densidade Demográfica , Portugal
20.
Ecosystems ; 24(6): 1361-1377, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33288980

RESUMO

Fagus sylvatica (beech) dominates the montane forests of the Apennines and builds old-growth high-conservation value stands. However, recent severe drought-induced diebacks raise concern on the future persistence of these forests and of Southern European mesophilous woodlands overall, growing at their dry edge. To explore the history of Apennine beech-dominated forests, we draw on the multiproxy paleoecological record from Lago Verdarolo, which includes a robust vegetation-independent temperature reconstruction. Numerical techniques are used to investigate the drivers of long-term Mediterranean mountain forest dynamics. Specifically, we focus on disentangling the ecological factors that caused the shift from high-diversity mixed forests to beech-dominated stands and on assessing the occurrence of legacy effects on present-day forests. Abrupt climate change largely drove vegetation dynamics during the Late Glacial and Early Holocene. Species-rich mixed Abies alba (silver fir) forests dominated about 10,500-5500 years ago, under rather dry and warmer-than-today conditions (+ 1-2 °C) and limited fire occurrence. Cooler and moister summers and increasing fire activity caused declines in several fire-sensitive temperate deciduous trees (for example, Ulmus, Tilia, Fraxinus) and favored the establishment of fir-beech forests around 5500 years ago. Further enhancement of fire activity and farming around 2000 years ago led to local Abies alba extinction and forest impoverishment. We conclude that the currently widespread monospecific Apennine beech forests are the result of multi-millennial land-use intensification superimposed on Late Holocene cooling and moistening. Given their higher drought-tolerance compared to beech stands, reviving ancient species-rich mixed fir forests represents a feasible and 'tested' possibility to adapt forests to climate change.

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