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We describe the career of John Birks as a pioneering scientist who has, over a career spanning five decades, transformed palaeoecology from a largely descriptive to a rigorous quantitative science relevant to contemporary questions in ecology and environmental change. We review his influence on students and colleagues not only at Cambridge and Bergen Universities, his places of primary employment, but also on individuals and research groups in Europe and North America. We also introduce the collection of papers that we have assembled in his honour. The papers are written by his former students and close colleagues and span many of the areas of palaeoecology to which John himself has made major contributions. These include the relationship between ecology and palaeoecology, late-glacial and Holocene palaeoecology, ecological succession, climate change and vegetation history, the role of palaeoecological techniques in reconstructing and understanding the impact of human activity on terrestrial and freshwater ecosystems and numerical analysis of multivariate palaeoecological data. [ABSTRACT FROM AUTHOR]

The development since the beginning of the 20th century of the pollen-analytical theory and method as a palaeoecological tool for describing landscape development is outlined with reference to southern Scandinavia. Numerical methods applied since the 1980s are discussed. The aim of this paper is to provide a new perspective on the landscape development and human impact during the Holocene by applying the Regional Estimates of VEgetation Abundance from Large Sites (REVEALS) model to the pollen records from the reference site Lake Färskesjön in SE Sweden. The model was applied both to a previously published record (core 1956, entire Holocene until ad 1600) and a newly collected dataset (core 2013, the last 3000 years). The comparison between the REVEALS estimates of vegetation cover and historical landscape maps indicate that traditional, uncorrected pollen percentages significantly underestimate the degree of landscape openness created by long-term farming and pasturing, but that the degree of underestimation varies over time, depending on the species composition of both the forest and the open-land communities. The REVEALS reconstructions are also a useful tool for the quantification of past land-use changes that may have affected the nutrient loading to the Baltic Sea. [ABSTRACT FROM AUTHOR]

Dating the transgression and subsequent regression in marginal basins of the southeastern Swedish Baltic Sea provides a new perspective of global ice-volume changes and the isostatic adjustment of the mantle after the retreat of the Scandinavian Ice Sheet from this area. Superimposed upon a smooth pattern of local sea-level rise, acceleration occurred ca. 7600 calibrated (cal) yr B.P., evidenced as a nearly synchronous flooding in six elevated basins ranging from 3.0 to 7.2 m above present sea level. We ascribe this rapid local sea-level rise of ∼4.5 m to a sudden increase in ocean mass, most likely caused by the final decay of the Labrador sector of the Laurentide Ice Sheet. The subsequent monotonic fall of local sea level from ca. 6500 cal yr B.P. to the present is mainly an expression of the slow isostatic adjustment of the mantle. [ABSTRACT FROM AUTHOR]

To estimate Holocene changes in organic carbon mass accumulation rates (Corg MARs) in the southeastern Swedish Baltic Sea, two sediment cores were studied in combination with biogeochemical modelling. Prior to 11 300 cal. BP, Corg MARs were extremely low, indicating low organic matter production on the catchment of the Baltic Ice Lake. Following a brief regression, the Ancylus Lake stage occurred between 11 100 and 9800 cal. BP. Corg MARs increased substantially during this period because of enhanced washing in of terrestrial organic matter, when boreal forests were initially established. The prominent marine stage, known as the Littorina transgression between 8500 and 3000 cal. BP, is marked by a minor increase in Corg MARs. Our modelling reveals a changing terrestrial organic carbon input between 100 and 1000 g/m² per yr that accounts for 30–80% of total organic carbon in sediments of the southeastern Swedish Baltic Sea, with maximum values (c. 20 X 10³g/m² per yr) occurring during the Bronze/Iron Age transition at about 3000 cal. BP. Corg MAR in the entire Baltic basin is estimated at 3.01 X 106 t/yr during the pre-industrial Holocene, comparable with other large inland water bodies. Regardless of the source of carbon, our data indicate that the Baltic basin is an important sedimentary reservoir for organic carbon storage and thus should be included in accounting for global terrestrial carbon cycling during the pre-industrial Holocene. [ABSTRACT FROM AUTHOR]

High-resolution palaeoecological proxies of pollen, macrofossils and diatoms from an isolation lake provide a long-term record of the Holocene landscape history and shoreline displacement on the Biskopsmåla Peninsula in central Blekinge, SE Sweden. During the Preboreal/Boreal transition, the peninsula was sparsely vegetated by woodlands, along with lateglacial dwarf shrub/steppe communities. The lake basin was isolated from the shallow Yoldia Sea during this time. The regional climate improved from 10 700 cal. BP, evident as progressive expansion of Pinus -dominated mixed forest with deciduous trees. The lake basin was probably connected with the Ancylus Lake during the period 10 700-10 100 cal. BP. Subsequently the basin became isolated again, corresponding to the Early Littorina Sea phase. Replacement of freshwater diatoms by those with brackish-water affinity at 8100 cal. BP indicates the initial transgression of the Littorina Sea in this basin. But not until 7500 cal. BP were brackish conditions fully established. Peaks of brackish-marine diatoms and dinoflagellates during 7500-7000 cal. BP indicate increased saltwater inflow to the Baltic Sea in response to global meltwater pulse 3. However, interactive changes in seagrass and stonewort macrofossil concentrations suggest that three minor transgressions during 5900-5300, 5000-4700 and 4400-4000 cal. BP occurred locally, associated with centennial-scale variations in regional wind pattern or coastal storminess. By 3000 cal. BP, the lake basin was finally isolated from the Baltic, and thereafter the landscape on the peninsula became gradually more influenced by human activities. [ABSTRACT FROM AUTHOR]