Kari Loe Hjelle

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 (Rrel) 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.

Modern pollen assemblages from mown and grazed vegetation types in western Norway

Abstract The aim of this study was to investigate pollen–vegetation relationships on a local scale and to identify grazed and mown vegetation types by their pollen assemblages. Vegetation frequency analysis and pollen analysis of surface moss polsters from grazed and mown vegetation types in western Norway were carried out. Five one-square-metre plots within 10×10 m plots from 36 different sites were investigated using classification (TWINSPAN, DISCRIM) and ordination (correspondence analysis, canonical correspondence analysis) methods. The pollen assemblages reflected the local vegetation and there was good agreement between the classifications and ordinations of the two data sets. This agreement occurred despite both the inclusion of extralocal and regional pollen and the low representation of entomophilous species affecting the pollen assemblages. Gradients were found in the pollen assemblages relating to land-use practices as well as geographical regions. Pollen assemblages from heath were separated from the other investigated vegetation types and characterized by high percentages of Calluna. A pollen-analytical separation of mown meadows from grazed sites was identified, whereas a separation between mown meadows and grazed sites which had previously been mown was found to be unclear. Plantago lanceolata, Rumex acetosa type, Ranunculus acris type, and Asteraceae Cichorioideae were common in both mown and grazed vegetation types. Galium type, Cirsium type, and Succisa were more associated with grazing than mowing, whereas the opposite was true for e.g. Achillea type, Alchemilla, and Conopodium majus type and several pollen types were connected with the mown meadows. The modern pollen assemblages from mown and grazed vegetation types may aid in the identification of past hay meadows and pastures from local pollen diagrams.

Relationships between pollen and plants in human-influenced vegetation types using presence-absence data in western Norway

Abstract The presence of plants within square metre plots and of their pollen in moss samples within the same plots was recorded in mowed and grazed vegetation types in western Norway. The relationship between plant and pollen presences was quantified using association, over- and under-representation indices. Each taxon was related to its mode of pollination and characteristics of the flowers as well as to the size of its pollen grain. A pattern was found for anemophilous species and for species with open blossoms and numerous freely exposed anthers. These had the best association between the presence of the pollen and the plant. Their pollen was also found more often in the pollen assemblages than in the vegetation, and their pollen grain sizes are most often less than 40 μm. Entomophilous species with few freely exposed anthers or concealed anthers were found to have a good association between plant and pollen presences or, most often, they were under-represented. Different pollen grain sizes are connected to this group. These results indicate that the presence of pollen of specialized entomophilous taxa and of pollen of taxa with open flowers, but few anthers reflect local occurrence in the vegetation. Their presence may therefore be important in interpreting land-use practices in pollen diagrams from soil profiles, whereas pollen percentages must be taken into account in interpreting the occurrence of pollen of anemophilous taxa and entomophilous taxa with open flowers and numerous exposed anthers from soil deposits.

Estimating pollen productivity and relevant source area of pollen using lake sediments in Norway: How does lake size variation affect the estimates?

This study aims to estimate relative pollen productivity (PPEs) of major pollen types and the relevant source area of pollen (RSAP) in a semi-open landscape in western Norway. Extended R-value (ERV) models are used to analyse a data set consisting of surface pollen assemblages from 34 lakes and vegetation survey around each site. Ordination techniques indicate relatively short gradients (<2.3 SD) both in the vegetation and pollen data sets. The lake sizes vary from 0.4 ha to 19.0 ha (mean=5.7 ha, sd=4.3 ha) but follow a normal distribution – a departure from the assumption of the ERV models that the lake size should be constant among sites. Simulations demonstrate that, if the sizes of circular-shaped lakes follow a normal distribution, the ERV model-based methods provide the expected PPE and RSAP values using a standardized lake radius. If the distribution is highly skewed or equally random around the mean, the results are not reliable. We apply the analytical strategy implied from the simulations to obtain relative PPEs and the RSAP in western Norway. PPEs for ten taxa (Alnus, Fagus, Picea, Pinus, Quercus, Juniperus, Salix, Calluna, Cyperaceae, Rumex) relative to Poaceae are comparable with some of those previously obtained in different parts of Europe, indicating that there are general patterns of high and low pollen producers that will be useful for reconstruction purposes. The RSAP estimate is the area within a radius of 900–1100 m. This study demonstrates the importance of careful evaluation of the extent to which the departures from the model assumptions affect the outcomes from the ERV model-based analysis.

Hesitant hunters: a review of the introduction of agriculture in western Norway

Abstract Evidence for the introduction of agriculture in western Norway is presented, using three categories of data: (1) palaeobotanical data, including pollen diagrams from lakes, bogs and archaeological sites, focusing on the presence of cereals, Plantago lanceolata L. and anthropogenic pollen indicators, and charred macro remains of cereals from archaeological sites; (2) osteological data, focusing on the occurrences of bones of cattle, sheep and goats in three rock-shelters, and the bone material from one open-air Neolithic site; (3) archaeological data, including artefacts indicating agricultural practices, distribution of residential settlement sites, and stray finds. The evidence for agricultural activity at the beginning of the fourth millennium BC (Early Neolithic, EN) is low, whereas the presence of both cereals and animal husbandry is indicated in the palaeobotanical material from the Middle Neolithic A (MNA, 3400–2600 cal. BC). The earliest record of domesticated animal bones is dated to the Middle Neolithic B (MNB, 2600–2200 cal. BC), while palynological and archaeological data also indicate an expansion in the area cultivated by early farmers. All data confirm the establishment of an agrarian society and animal husbandry in the Late Neolithic (LN, 2200–1700 cal. BC). It is concluded that agriculture was introduced into western Norway by the indigenous hunter-fisher populations. During this process, social and ideological factors played principal roles.

Ecology and long-term land-use, palaeoecology and archaeology – the usefulness of interdisciplinary studies for knowledge-based conservation and management of cultural landscapes

Natural and cultural heritage management is dependent on knowledge about present species and habitats and presence of cultural heritage sites, respectively. Knowledge about long-term development helps to identify factors explaining both biodiversity and cultural heritage and to predict future changes based on changes in, for example, climate or grazing regimes. In the present interdisciplinary study, vegetation surveys, pollen analysis from a bog and soil profiles within archaeological localities, archaeological test-excavations and historical data have been combined to elucidate cultural landscape development in an upland landscape of Erdalen in Stryn, western Norway. Activity in what is now the summer farm area started in the Bronze Age, followed by clearance and grazing in the Early Iron Age. After a period of reduced activity, most of the valley seems to have been utilised for summer farming in the Late Iron Age and first part of the Medieval Period. A regression period, probably related to the Black Death, is followed by new activity with extensive woodland clearings from the seventeenth century, whereas recent changes have resulted in increased tree cover. The investigations show a close relationship between land-use practices, presence of grassland species and vascular plant species richness. They also show the importance of continued management for existence of semi-natural habitats in the future, and for the visibility of archaeological sites.

Long-term changes in regional vegetation cover along the west coast of southern Norway: The importance of human impact

Special Feature “Millennial to centennial vegetation change” (Eds. Thomas Giesecke, Petr Kuneš & Triin Reitalu). 1Department of Natural History, University Museum, University of Bergen, Bergen, Norway 2Department of Biological Sciences, University of Bergen, Bergen, Norway 3Museum of Archaeology, University of Stavanger, Stavanger, Norway 4Institute of Ecology, Tallinn University, Tallinn, Estonia 5Museum of Cultural History, University of Oslo, Oslo, Norway