Modern pollen/land-use relationships as an aid in the reconstruction of past land-uses and cultural landscapes: an example from south Sweden

An on-going, integrated project concerning modern pollen/vegetation/land-use relationships in south Sweden is outlined. Some preliminary results and their potential uses in palaeoecological reconstructions are discussed. Moss polsters were collected from 92 examples of vegetation/land-use areas of south Sweden (e.g. nonfertilized grazed areas, burned and grazed heaths, traditionally managed fodder-producing meadows, etc.). A total of 23 land-use (e.g. management type) and environment variables (e.g. soil chemistry) is available for 84 sites. The 84 sample data-set was analysed by canonical correspondence analysis and associated statistical testing using Monte Carlo permutation tests to explore and test patterns of modern pollen variation in relation to the environment, and by weighted averaging regression and calibration to derive local-scale environmental and land-use reconstructions from fossil pollen assemblages preserved in a soil profile.     

Modern pollen samples from alpine vegetation on the Tibetan Plateau

• 1 A set of 316 modern surface pollen samples, sampling all the alpine vegetation types that occur on the Tibetan Plateau, has been compiled and analysed. Between 82 and 92% of the pollen present in these samples is derived from only 28 major taxa. These 28 taxa include examples of both tree (AP) and herb (NAP) pollen types.
• 2 Most of the modern surface pollen samples accurately reflect the composition of the modern vegetation in the sampling region. However, airborne dust‐trap pollen samples do not provide a reliable assessment of the modern vegetation. Dust‐trap samples contain much higher percentages of tree pollen than non‐dust‐trap samples, and many of the taxa present are exotic. In the extremely windy environments of the Tibetan Plateau, contamination of dust‐trap samples by long‐distance transport of exotic pollen is a serious problem.
• 3 The most characteristic vegetation types present on the Tibetan Plateau are alpine meadows, steppe and desert. Non‐arboreal pollen (NAP) therefore dominates the pollen samples in most regions. Percentages of arboreal pollen (AP) are high in samples from the southern and eastern Tibetan Plateau, where alpine forests are an important component of the vegetation. The relative importance of forest and non‐forest vegetation across the Plateau clearly follows climatic gradients: forests occur on the southern and eastern margins of the Plateau, supported by the penetration of moisture‐bearing airmasses associated with the Indian and Pacific summer monsoons; open, treeless vegetation is dominant in the interior and northern margins of the Plateau, far from these moisture sources.
• 4 The different types of non‐forest vegetation are characterized by different modern pollen assemblages. Thus, alpine deserts are characterized by high percentages of Chenopodiaceae and Artemisia, with Ephedra and Nitraria. Alpine meadows are characterized by high percentages of Cyperaceae and Artemisia, with Ranunculaceae and Polygonaceae. Alpine steppe is characterized by high abundances of Artemisia, with Compositae, Cruciferae and Chenopodiaceae. Although Artemisia is a common component of all non‐forest vegetation types on the Tibetan Plateau, the presence of other taxa makes it possible to discriminate between the different vegetation types.
• 5 The good agreement between modern vegetation and modern surface pollen samples across the Tibetan Plateau provides a measure of the reliability of using pollen data to reconstruct past vegetation patterns in non‐forested areas.

     

Effects of habitat management on vegetation and above-ground nesting bees and wasps of orchard meadows in Central Europe

We studied the vegetation, stand structure and communities of above-ground nesting bees and wasps in 45 orchard meadows that were grazed, mown or abandoned (15 of each) in an agricultural landscape near Göttingen, Germany. Total species richness of plants was significantly lower and the proportion of dead wood was significantly higher on abandoned meadows compared to mown or grazed meadows. Species richness of bees, eumenid wasps and sphecid wasps did not differ between the three management types. Abundance of sphecid wasps was significantly higher on abandoned than on managed orchard meadows. Landscape context did not affect management type. The results suggest that management practises affect vegetation more significantly than the studied insect groups.     

Numerical analysis of modern and fossil pollen spectra as a tool for elucidating the nature of fine-scale human activities in boreal areas

Modern pollen assemblages from the major vegetation units (both natural and anthropogenic) on the island of Hailuoto, Finland are studied from 29 surface moss samples. A total of 59 pollen and spore taxa are recorded. The pollen data-set is related by redundancy analysis (RDA) to six external synthetic variables that characterize in general terms the different major ecological situations relevant to the land-use on the island (sand, humus, forest, field, deforested, treeless). Weighted average (WA) optima are calculated to identify which pollen taxa are most indicative of four of these external variables. Two fossil pollen diagrams from Hailuoto are re-interpreted by positioning their samples on the RDA plot of the modern data-set and by classifying the modern and fossil spectra together in a minimum-variance cluster analysis. The RDA plot shows that the strongest features in the modern pollen assemblages are the contrast between spectra from dry sandy soils and those from damper soils with more organic content, and between assemblages from forested and unforested areas. For anthropogenic situations the numerical analyses detect a distinction in the pollen assemblages characterizing fields from those representing farms and trackways but is less successful in separating the latter two. The WA optima indicate that most pollen taxa considered as indicator types primarily represent a mixed field/farm category of land-use. The RDA and minimum-variance cluster analysis confirm that the two fossil sites have had different vegetational histories. In neither is there any phase equivalent to the modern farm situation on Hailuoto. The initial phase in each diagram represents shore meadows and fields but because Poaceae pollen is identifiable only to family level it is not possible to separate these two habitat types.     

A survey of modern pollen and vegetation along a south–north transect in Mongolia

Aim This modern pollen‐rain study documents the spatial and quantitative relationships between modern pollen and vegetation in Mongolia, and explores the potential for using this relationship in palaeoclimatic reconstructions. Location East‐central Mongolia. Methods We collected 104 pollen surface samples along a south–north transect across five vegetation zones in Mongolia. Discriminant analysis was used to classify the modern pollen spectra into five pollen assemblages corresponding to the five vegetation zones. Hierarchical cluster analysis was used to divide the main pollen taxa into two major groups and seven subgroups representing the dry and moist vegetation types and the main vegetation communities within them. Results Each vegetation zone along the transect can be characterized by a distinctive modern pollen assemblage as follows: (1) desert zone: Chenopodiaceae–Zygophyllaceae–Nitraria–Poaceae pollen assemblage; (2) desert‐steppe zone: Poaceae–Chenopodiaceae pollen assemblage; (3) steppe zone: Artemisia–Aster‐type–Poaceae–Pinus Haploxylon‐type pollen assemblage; (4) forest‐steppe zone: Pinus Haploxylon‐type–Picea–Artemisia–Betula, montane forb/shrub and pteridophyte pollen assemblage; and (5) mountain taiga zone: Pinus Haploxylon‐type–Picea–Poaceae–Cyperaceae, montane forb/shrub and Pteridophyte pollen assemblage. Main conclusions Based on the ratio between the major pollen taxon groups and subgroups, we propose two pollen–climate indices that represent the precipitation and temperature conditions in the study region. When plotted along our south–north transect, the moisture indices (M) and temperature indices (T) mimic the regional gradients of precipitation and temperature across Mongolia very closely. These pollen–climate indices can be used for palaeoclimatic reconstruction based on fossil pollen data.     

Interpretation of the last‐glacial vegetation of eastern‐central Europe using modern analogues from southern Siberia

Aim Interpretation of fossil pollen assemblages may benefit greatly from comparisons with modern palynological and vegetation analogues. To interpret the full‐ and late‐glacial vegetation in eastern‐central Europe we compared fossil pollen assemblages from this region with modern pollen assemblages from various vegetation types in southern Siberia, which presumably include the closest modern analogues of the last‐glacial vegetation of central Europe. Location Czech and Slovak Republics (fossil pollen assemblages); Western Sayan Mountains, southern Siberia (modern pollen assemblages). Methods Eighty‐eight modern pollen spectra were sampled in 14 vegetation types of Siberian forest, tundra and steppe, and compared with the last‐glacial pollen spectra from seven central European localities using principal components analysis. Results Both full‐ and late‐glacial pollen spectra from the valleys of the Western Carpathians (altitudes 350–610 m) are similar to modern pollen spectra from southern Siberian taiga, hemiboreal forest and dwarf‐birch tundra. The full‐glacial and early late‐glacial pollen spectra from lowland river valleys in the Bohemian Massif (altitudes 185–190 m) also indicate the presence of patches of hemiboreal forest or taiga. Other late‐glacial pollen spectra from the Bohemian Massif suggest an open landscape with steppe or tundra or a mosaic of both, possibly with small patches of hemiboreal forest. Main conclusions Our results are consistent with the hypothesis that during the full glacial and late glacial, the mountain valleys of the north‐western Carpathians supported taiga or hemiboreal forest dominated by Larix, Pinus cembra, Pinus sylvestris and Picea, along with some steppic or tundra formations. Forests tended to be increasingly open or patchy towards the west (Moravian lowlands), gradually passing into the generally treeless landscape of Bohemia, with possible woodland patches in locally favourable sites.     

Anthropogenic and climatic impacts on surface pollen assemblages along a precipitation gradient in north‐eastern China

Aim To understand the scenarios of ‘anthropogenic biomes’ that integrate human and ecological systems, we need to explore the impacts of climate and human disturbance on vegetation in the past and present. Interactions among surface pollen, modern vegetation and human activities along climate and land‐use gradients are tested to evaluate the natural and anthropogenic forces shaping the modern vegetation, and hence to aid the reconstruction of vegetation and climate in the past. This in turn will help with future predictions. Location The North‐east China Transect (NECT) in north‐eastern China. Methods We analysed 33 surface pollen samples and 213 quadrats across four vegetation zones along the moisture/land‐use gradients of the NECT. Detrended correspondence analysis (DCA) and redundancy analysis (RDA) of 52 pollen taxa and three environmental variables were used to distinguish anthropogenic and climatic factors that affect surface pollen assemblages along the NECT. Results The 33 surface samples are divided into four pollen zones (forest, meadow steppe, typical steppe and desert steppe) corresponding to major vegetation types in the NECT. Variations in pollen ratios of fern/herb (F/H), Artemisia/Chenopodiaceae (A/C) and arboreal pollen/non‐arboreal pollen (AP/NAP) represent the vegetation and precipitation gradient along the NECT. DCA and RDA analyses suggest that surface pollen assemblages are significantly influenced by the precipitation gradient. Changes in the abundance of Chenopodiaceae pollen are related to both human activities and precipitation. Main conclusions Surface pollen assemblages, fossil pollen records, archaeological evidence and historical documents in northern China show that a large increase of Chenopodiaceae pollen indicates human‐caused vegetation degradation in sandy habitats. The A/C ratio is a good indicator of climatic aridity, but should be used in conjunction with multiple proxies of human activities and climate change in the pollen‐based reconstruction of anthropogenic biomes.     

Are ecological compensation areas attractive hunting sites for common kestrels (Falco tinnunculus) and long-eared owls (Asio otus)?

Common kestrels (Falco tinnunculus) and long-eared owls (Asio otus) in intensively farmed areas in Switzerland decreased markedly as a result of declining vole (Microtus spp.) populations. In order to counteract the loss of biodiversity in intensively farmed areas, the Swiss agri-environment scheme stipulates several types of ecological compensation areas, which together should take up 7% of the farmland. Among them are wild flower and herbaceous strips, which are not mown every year and which in summer support up to 8 times more small mammals than ordinary fields and grassland. This study investigates whether kestrels and long-eared owls preferentially hunt on ecological compensation areas and whether preferred hunting areas are related to the density of small mammals or to the density and height of the vegetation. Both kestrels and long-eared owls mainly hunted on freshly mown low-intensity meadows and artificial grassland, despite low densities of small mammals. Therefore, vegetation structure was more important for the selection of hunting sites than prey abundance. However, both predators preferred to hunt on freshly mown grassland and meadows bordering a wild flower or herbaceous strip. Voles from these strips probably invaded the adjacent freshly mown grassland and became an easy prey for kestrels and owls. In intensively farmed regions, ecological compensation areas, particularly those not mown each year, are an important refuge for small mammals, although in summer the small mammals are not directly accessible to hunting birds. Hence, a mosaic of different habitat types with grassland mown at different times of the year together with undisturbed strips is best suited to provide a year-round supply of accessible food for vole hunters.     

Population structure of the threatened perennial Serratula tinctoria in relation to vegetation and management

Question: How does vegetation and management affect the population stage structure of Serratula tinctoria, a species indicative of highly endangered and species‐rich flood‐plain meadows? Are different management regimes suitable to support viable populations of S. tinctoria? Location: Flood‐plain of the northern Upper Rhine, Germany. Methods: We analysed the population structure of S. tinctoria at 24 meadow sites which differed in vegetation and management. In this comparative study the investigated meadows were either (1) late mown in September; (2) early mown in June or (3) mown in June and then grazed by sheep. Results: The structure of the surrounding vegetation had a clear effect on the population structure of S. tinctoria. The percentage of bare soil, as well as the cover of bryophytes, were positively related, whereas the Ellenberg N‐value of the established vegetation was negatively related to the density and proportion of seedlings. Generally, we found only slight differences between the population structure of S. tinctoria in early and late mown meadows. Both management regimes had high densities of seedlings. In contrast, the meadow pastures supported significantly lower densities of seedlings and generative adults but relatively high densities of juveniles and vegetative adults, indicating a greater importance of clonal propagation under grazing pressure. Conclusions: Our results clearly showed that viable populations of S. tinctoria may occur in all of the studied management regimes. Although S. tinctoria was considered to be highly sensitive to early mowing, our findings suggest a facilitation of the species at more nutrient‐rich sites by mowing in June, which is also a benefit for the integration of management in farming systems.     

Modern pollen–vegetation relationships along transects on the Whangapoua Estuary, Great Barrier Island, northern New Zealand

Aims To quantify pollen–vegetation relationships from saline to freshwater in an estuarine gradient from surface samples of the modern pollen rain, to allow more accurate interpretations of the stratigraphic palynological record. Location Whangapoua Estuary, Great Barrier Island, northern New Zealand. Methods Six transects were laid out along a vegetation sequence running from estuarine mud to freshwater swamp. Along these transect lines, 108 plots were sampled for vegetation and surface sediments from wet sand, mud, plant litter or moss (sand and mud sites are inundated by most tides, other sites less frequently). All sediment samples were analysed for pollen. The relationships between plant species frequency and pollen representation were examined at a community scale using twinspan and ordination analyses, and for individual species using fidelity and dispersibility indices, regression and box‐plot analyses. Results The quantitative relationships between source taxon vegetation frequency and its pollen representation varied between species due to differential pollen production and dispersal. twinspan of the surface pollen samples suggests five vegetation types: (A) mangrove (Avicennia marina); (C) Leptocarpus similis salt meadow; (D) Baumea sedges; (E) Leptospermum shrubland; and (F) Typha/Cordyline swamp forest. The (B) Juncus kraussii community is not represented palynologically owing to the destruction of its delicate pollen grains during acetolysis of samples. Detrended correspondence analysis places these communities on an estuarine‐to‐freshwater gradient. However, pollen assemblages at the seaward end of the salinity gradient are less clearly representative of the associated vegetation than those at the landward end, probably because the open vegetation at the former allows the influx of wind‐ and water‐dispersed pollen from surrounding vegetation. Main conclusions The vegetation pattern (zonation) at Whangapoua is reflected in the pollen rain. When the long‐distance and over‐represented pollen types are excluded, five out of six of the broad vegetation communities can be identified by their pollen spectra. Species with high fidelity and low‐to‐moderate dispersibility indices can be used to identify the vegetation types in the sedimentary sequences. The more open vegetation types at the ‘marine end’ of the sequence tend to be ‘overwhelmed’ by regional pollen, but the nature of the sediments and the presence of discriminatory species (e.g. A. marina, Plagianthus divaricatus, Cordyline australis), even in small amounts, will allow correct identification of the local vegetation represented in sedimentary palynological sequences. A box‐plot analysis indicates that the pollen and spore types A. marina (mangroves), Sarcocornia quinqueflora (salt meadow), P. divaricatus (sedges), Gleichenia (shrubland) and C. australis (swamp forest) are highly discriminatory in relation to vegetation type. These discriminatory palynomorphs help with the interpretation of stratigraphic pollen studies. However, salt marsh vegetation communities in the sediments must be interpreted with caution as the marine sediments are easily affected by erosion, bioturbation and tidal inundation effects.     

Vegetation changes following sheep grazing in abandoned mountain meadows

Abstract. Sheep grazing was investigated as an alternative to traditional management of meadows in the Krkono?e Mts. Until the second World War these meadows were mown in mid‐summer and grazed by cattle for the rest of the season. Subsequent abandonment of the meadows has resulted in decreasing species richness. Degradation phases of the former communities have been replacing the original species‐rich vegetation. Significant changes were apparent six years after the introduction of sheep grazing. In grazed plots the proportion of dominant herbs (Polygonum bistorta and Hypericum maculatum) decreased and grasses (Deschampsia cespitosa, Festuca rubra, Agrostis capillaris, Anthoxanthum alpinum) increased. The increase in grasses was positively correlated with an increase in several herbs. The proportion of some herbs increased despite being selectively grazed (Adenostyles alliariae, Melandrium rubrum, Veratrum lobelianum). Any losses caused by grazing of mature plants were probably compensated by successful seedling establishment. Cessation of grazing resulted in significant changes in vegetation within three years. The cover of nitrophilous tall herbs and grasses (e.g. Rumex alpestris, Holcus mollis, Deschampsia cespitosa, Geranium sylvaticum) increased in the abandoned plots. In the plots grazed for nine years cover of species‐rich mountain meadow species increased (e.g. fine‐leaved grasses, Campanula bohemica, Potentilla aurea, Viola lutea, Silene vulgaris). The main conservation risk is the expansion of a competitive species with low palatability, Deschampsia cespitosa. This species can be suppressed by a combination of grazing and mowing. In order for grazing to be effective, the number of sheep should be proportional to meadow production. This may be difficult to maintain as production is variable and is impossible to predict at the beginning of a growing season. A large part of the biomass may thus remain intact in some years. Negative effects of grazing may be, at least partly, eliminated by a combination of cutting and grazing.     

Reliability of pollen ratios for environmental reconstructions on the Tibetan Plateau

Aim Pollen ratios are widely used to gain palaeovegetation and palaeoclimatic information from fossil pollen spectra, although their applicability has seldom been tested with modern pollen data. I used a data set of 113 lake‐surface sediments from the eastern Tibetan Plateau to test the reliability of several pollen ratios. Location The lake‐surface pollen spectra cover a wide range of vegetation types (temperate desert, temperate steppe, alpine desert, alpine steppe, high‐alpine meadow, sub‐alpine shrub, coniferous and mixed forest) and climatic conditions (mean July temperature, T_July: 4.0–17.4°C; mean annual precipitation, P_ann: 104–670 mm). Methods Lake‐surface sediments were analysed palynologically, and several pollen ratios were calculated. These ratios were interpreted with respect to vegetation and climatic conditions. Results The arboreal pollen sum (AP) was highest in samples from forested areas and was significantly correlated with P_ann (r² = 0.44). In non‐forested areas, samples from large lakes and from lakes surrounded by sparse vegetation had increased AP values, suggesting that AP is a useful vegetation density indicator. Artemisia/Chenopodiaceae (A/C) ratios were lowest in desert areas and were positively correlated with P_ann (r² = 0.25). The aridity pollen index was inappropriate for inferring (palaeo‐)climatic information from samples on the eastern Tibetan Plateau as it had no significant correlation with the environmental factors. Artemisia/Cyperaceae (A/Cy) ratios had a significant correlation with T_July (r² = 0.23), but only a weak correlation with P_ann, which indicates that the A/Cy ratio is applicable as a temperature indicator. Furthermore, it is a valuable tool for the differentiation of high‐alpine meadow from steppe vegetation. Main conclusions AP sum, A/C ratio and A/Cy ratio are useful tools for qualitative and semi‐quantitative palaeoenvironmental reconstruction on the Tibetan Plateau; however, the results obtained should not be interpreted quantitatively.     

Modern pollen rain in mangroves from San Andres Island, Colombian Caribbean

The precise characterisation of present-day mangrove ecosystems from modern pollen rain facilitates the accurate use of fossil pollen data for late Quaternary sea level and environmental reconstructions. Here, we investigate whether the analysis of pollen rain data corroborates existing floristic and structural characterisation of different mangrove types at the Caribbean island of San Andrés, Colombia. At 82 plots along 20 transects of four distinct mangrove types, samples were obtained of (i) surface sediments for pollen analysis, and (ii) a range of environmental parameters (including inundation levels, salinity and pH). This information was compared to previously sampled mangrove composition and tree basal area. In surface sediment samples 82 pollen taxa were found, from which 19 were present in the vegetation plots. However, because pollen may be transported by wind and/or watercourses, the overall floristic composition of the different forest types may not necessarily be reflected by the pollen spectra. Local vegetation (i.e. mangroves and beach) represented > 90% of the pollen spectra, while the regional one (i.e. hinterland forests) represented < 5% of it. Unlike the four mangrove types that were previously described in the vegetation, the analysis of pollen samples suggested only three distinct types of forest.The groups were characterised based on (i) the dominance of at least one of the true mangrove species from pollen data ordination and the presence of associated species, and (ii) their relationship with environmental parameters. Rhizophora was present in all plot samples, but did not contribute to forest type separation. In fact, just three true mangrove species proved reliable indicators of (i) high salinity and fringe mangroves (i.e. Avicennia), (ii) high pH levels and landward mangroves (i.e. Conocarpus), and (iii) natural or anthropogenic caused disturbance of forest stands (Laguncularia and associated Acrostichum fern). Hence our study confirms that mangrove pollen spectra can be accurately used to describe different mangrove environments for fossil based palaeoecological reconstructions.     

Modern vegetation–pollen–climate relationships for the Pampa grasslands of Argentina

Aim To analyse the relationships between potential natural vegetation, pollen and climate in order to improve the interpretation of fossil pollen records and provide the background for future quantitative palaeoclimatic reconstructions. Location Pampa grasslands of Argentina, between 33–41° S and 56–67° W. Methods Modern pollen data were obtained from a pollen data base developed by the Grupo de Investigación de Paleoecología y Palinología, Universidad Nacional de Mar del Plata, Argentina (143 surface samples and 17 pollen types). Analysis of pollen and climate data involved multivariate statistics (cluster analysis and principal components analysis), scatter diagrams, Pearson’s correlation and isopoll mapping. Results Vegetation patterns at regional scales (grasslands and xerophytic woodlands) and local scales (edaphic communities) were identified by cluster analysis of pollen surface samples. The main climatic variables that appear to constrain the vegetation distribution and abundance of taxa are mean annual precipitation, annual effective precipitation and summer temperature. Individual pollen types such as Chenopodiaceae, Apiaceae, Cyperaceae, Prosopis, Schinus, Condalia microphylla and other xerophytic taxa are good indicators of moisture regime. Many pollen types are significantly correlated with summer temperature. The modern vegetation–pollen–climate relationships vary in a broadly predictable manner, supporting the contention that fossil pollen assemblages can be related to particular climatic characteristics. Main conclusions An expanded suite of modern analogues facilitated new insights into vegetation–pollen–climate relationships at the regional scale in Pampa grasslands. Relationships between individual pollen types and climate are appraised at a regional scale and new modern analogues are presented. The results provide the basis for improved vegetation and climate reconstruction from fossil records of the study area.     

Herb pollen representation in surface moss samples from mown meadows and pastures in western Norway

Grazed and mown vegetation types in western Norway were investigated with the aim of describing their modern pollen/vegetation relationships as an aid to the interpretation of fossil pollen diagrams. Pollen surface samples and vegetation data were obtained from 186 square metre plots within 39 different sites of 10×10 m. Scatter plots that show the relationship between pollen percentages and vegetation percentages are presented forTrifolium pratense-type,Trifolium rcpens-type,Lotus, Campanula-type,Succisa, Ranunculus acris-type,Cirsium-type, Asteraceae Cichorioideae,Achillea-type,Potentilla-type, Apiaceae,Rumex sect.Acetosa, Galium-type, Cyperaceae,Calluna, Plantago lanceolata and Poaceae. Pollen representation factors relative to Poaceae (R_rel) are calculated for 54 pollen taxa. Differences in the values from different geographical areas were found in the case of some taxa, due to either different genera or species being included in the pollen taxa and/or to the different representation of high pollen producers in the different regional vegetation types. Background pollen influences the estimates for taxa such asR. sect.Acetosa, P. lanceolata, Poaceae, Cyperaceae, andCalluna, and an extended R-value (ERV) model was used to investigate the magnitude of this pollen component. Groups of roughly similar pollen representation were identified and factors to convert pollen percentages to vegetation abundances are suggested.     

Dynamics of North Patagonian rainforests from fine‐resolution pollen,charcoal and tree‐ring analysis,Chonos Archipelago,Southern Chile

Abstract Fine‐resolution palaeoecological and dendrochronological methods were used to investigate the impacts of climate change, and natural and anthropogenic disturbances on vegetation in the North Patagonian rainforest of southern Chile at decadal to century timescales during the late Holocene. A lake sediment mud–water interface core was collected from the northern Chonos Archipelago and analysed for pollen and charcoal. Dendrochronological analysis of tree cores collected from stands of Pilgerodendron uviferum close to the lake site was incorporated into the study. The combined analysis showed that the present mosaic of vegetation types in this region is a function of environmental changes across a range of timescales: millennial climate change, more recent natural and anthropogenic disturbances, and possibly short‐term climatic variations. Of particular interest is the spatiotemporal distribution of Pilgerodendron uviferum dieback/burning in the Chonos Archipelago region.     

Modern pollen assemblages from Reasi (Jammu and Kashmir), India: a tool for interpreting fossil pollen records

Twenty five surface samples/moss cushions were collected for palynological analysis from open areas of Reasi District, Jammu and Kashmir (India). These samples were used to investigate the relationships between extant vegetation and modern pollen spectra, which serve as modern analogue for the reliable ecological interpretation of fossil pollen records. The present vegetation in the region comprises tropical dry deciduous forests and subtropical pine forests with scattered stands of oak. The pollen analysis reveals that Pinus sp. (average 69% in the pollen assemblages), amongst the conifers, dominates the pollen rain, which can be attributed to its high pollen productivity and exceptional pollen dispersal efficiency. Cedrus sp. and Podocarpus sp. pollen contribute with an average of 16 and 5% to the total pollen rain. Other conifers such as Picea sp., Abies sp., Juniperus sp. and Tsuga sp., as well as broad-leaved taxa such as Quercus sp., Alnus sp., Betula sp., Carpinus sp., Corylus sp., Juglans sp., Ulmus sp., Salix sp., Elaeocarpus sp., Mallotus sp. and Aesculus sp., have lower averages of 1 to 4.5% in the total pollen rain which could be either due to their poor pollen dispersal efficiency or to the poor preservation in the samples. Tubuliflorae (average 25%), Poaceae (average 6.26%), Cerealia and other crop plants (average 7.68%) are other prominent taxa in the pollen rain. The nearly complete absence of members of tropical dry deciduous forests in the pollen spectra likely is due to the fact that most species in this vegetation type are not wind pollinated.     

Mowing management and density dependence in meadow passerine hatching success

Capsule Improving habitat quality through late or intermittent mowing may increase passerine population density without reducing reproductive success.

Aim To describe the relationship between passerine territory density (TD) and Whinchat Saxicola rubetra and Yellow Wagtail Motacilla flava hatching success, under different management regimes.

Methods TD was defined by the Territory Mapping method in nine sites selected in five French flood plains, in four intermittently mown meadows in Russia and in four additional French sites where mowing was partially postponed. Hatching success was assessed by the observation of prey carrying. Generalized Linear Mixed Models were used to analyse the influence on hatching rates of mowing management, early mowing and TD. Linear Mixed Models were used to study the effect of mowing management on TD.

Results In French early mown meadows, TD affected reproductive success. Higher hatching rates and TD were observed in Russia. Similar results in French study sites with postponed mowing confirmed the influence of mowing management on carrying capacity.

Conclusion In west-European grassland systems, late or intermittently mown patches within or at the edge of meadow areas, with potentially improved invertebrate-prey availability, should help to sustain bird demography and improve the efficiency of current conservation programmes.     

Correlation between spatial distributions of pollen data, archaeological records and physical parameters from north-western France: a GIS and numerical analysis approach

New methodologies using Geographical Information Systems (GIS) and statistical tools were developed to provide new elements to the interpretation of fossil pollen records on the large spatial scale of north-western France. The originality of these methods lies in the analysis of the spatial distribution of the archaeobotanical data in order to identify correlations with other spatial parameters such as geological, climatic, pedological, topographical and archaeological characteristics. 218 pollen analyses from north-western France and a series of thematic maps (geological, archaeological, climatic, etc.) were used. The application of numerical analyses makes it possible to describe the spatial distribution of pollen data at a regional scale, and to identify spatial correlations between pollen data and other environmental parameters, and between archaeobotanical groups, archaeological and abiotic parameters simultaneously. Two examples are presented and discussed: (A) The spatial distributions of the predominance of hazel over oak between 6700 and 5700 cal b.p. and of modern precipitation are shown to be positively correlated, i.e. hazel is dominant in the most humid areas of the region. (B) The pollen data from the Bronze Age show associations of (1) pollen groups ascribed to meadows, shrubland, and forests with cooler temperatures, higher altitudes and northern latitudes, and (2) pollen groups ascribed to moor environments and anthropogenic vegetation with warmer temperatures, southern latitudes and lower altitudes. The latter implies that the agricultural landscapes of the Bronze Age were mainly confined to southern latitudes and low altitudes of the region, while the areas characterised by high altitudes and low temperatures were characterised by extensive activities such as grazing by cattle. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Modern pollen–vegetation relationships in subarctic southern Greenland and the interpretation of fossil pollen data from the Norse landnám

Aim The objective of this paper is to explore the relationships that exist between vegetation and modern pollen rain in the open, largely treeless landscape of subarctic Greenland. The implications of these results for the interpretation of fossil pollen assemblages from the time of the Norse landnám are then examined. Location The study area is the sheep farming district of Qassiarsuk in the subarctic, subcontinental vegetational and climatic zone of southern Greenland (61° N, 45° W). Between c.ad 1000–1500 this region was contained within the Norse Eastern Settlement. Methods Detrended Correspondence Analysis (DCA) of harmonized plant–pollen data sets is used to compare plant cover in 64 vegetation quadrats with pollen assemblages obtained from moss polsters at matching locations. Presence/absence data are also used to calculate indices of association, over‐ and under‐representation for pollen types. Results Good correspondence between paired vegetation–pollen samples occurs in many cases, particularly in locations where Salix glauca–Betula glandulosa dwarf shrub heath is dominant, and across herbaceous field boundaries and meadows. Pollen samples are found to be poor at reflecting actual ground cover where ericales or Juniperus communis are the locally dominant shrubs. Dominant or ubiquitous taxa within this landscape (Betula, Salix and Poaceae) are found to be over‐represented in pollen assemblages, as are several of the ‘weeds’ generally accepted as introduced by the Norse settlers. Main conclusions Due to their over‐representation in the pollen rain, many of the Norse apophytes and introductions (e.g. Rumex acetosa and R. acetosella) traditionally used to infer human activity in Greenland should be particularly sensitive indicators for landnám, allowing early detection of Norse activity in fossil assemblages. Pteridophyte spores are found to be disassociated with the ground cover of ferns and clubmosses, but are over‐represented in pollen assemblages, indicating extra‐local or regional sources and long residence times in soil/sediment profiles for these microfossils. A pollen record for Hordeum‐type registered in close proximity to a field containing barley suggests that summer temperatures under the current climatic regime are, at least on occasion, sufficient to allow flowering.