Signals of tree volume and temperature in a high-resolution record of pollen accumulation rates in northern Finland

International audiencePollen accumulation rates (PARs) provide a potential proxy for quantitative tree volume (m3 ha 1) reconstruction with reliable absolute pollen productivity estimates (APPEs). We obtained APPEs for pine, spruce and birch at their range limits in northern Finland under two temperature periods ('warm' and 'cold') based on long-term pollen trap and tree volume records within a 14-km radius of each trap. APPEs (mean SE; 108 grains m 3 a 1) tend to be higher for the 'warm' periods (pine 123.8 24.4, birch 528.0 398.4, spruce 434.3 113.7) compared with the 'cold' periods (pine 95.5 37.3, birch 317.3 282.6, spruce 119.6 37.6), although the difference is only significant for spruce. Using an independent temperature record and the APPEs obtained, we reconstruct a low-frequency record of pine volume changes over the last 1000 years at Palomaa mire, where a high-resolution record of Pinus PARs is available. Five phases are distinguished in the reconstruction: moderate pine volume, AD 1080-1170; high volume, AD 1170-1340; low volume, AD 1340-1630; very low volume, AD 1630-1810; and rising pine volume, AD 1810- 1950. These phases do not coincide with periods of high or low June-July-August temperatures, and thus appear to reflect regional variations in tree volume, while high-frequency changes within each time-period block show variations in PARs in response to temperatur

The impact of land-use change on floristic diversity at regional scale in southern Sweden 600 BC-AD 2008

International audienceThis study explores the relationship between landuse and floristic diversity between 600BC and AD2008 in the uplands of southern Sweden. We use fossil pollen assemblages and the Regional Estimates of Vegetation Abundance from Large Sites (REVEALS) model to quantitatively reconstruct land cover at a regional scale. Floristic richness and evenness are estimated using palynological richness and REVEALS-based evenness, respectively. We focus on the period AD350 to 750 to investigate the impact of an inferred, short-lived (<200 yr) period of land-use expansion and subsequent land abandonment on vegetation composition and floristic diversity. The observed vegetation response is compared to that recorded during the transition from traditional to modern land-use management at the end of the 19th century. Our results suggest that agricultural land use was most widespread between AD350 and 1850, which correlates broadly with high values of palynological richness. REVEALS-based evenness was highest between AD500 and 1600 which indicates a more equal cover among taxa during this time interval. Palynological richness increased during the inferred land-use expansion after AD350 and decreased during the subsequent regression AD550-750, while REVEALS-based evenness increased throughout this period. The values of palynological richness during the last few decades are within the range observed during the last 1650 yr. However, REVEALS-based evenness shows much lower values during the last century compared to the previous ca. 2600 yr, which indicates that the composition of presentday vegetation is unusual in a millennial perspective. Our results show that regional scale changes in land use have had clear impacts on floristic diversity in southern Sweden, with a vegetation response time of less than 20 to 50 yr. We show the importance of traditional land use to attain high biodiversity and suggest that ecosystem management should include a regional landscape perspective

Floristic diversity in the transition from traditional to modern land-use in southern Sweden A.D. 1800-2008

International audienceWe aim to provide a long-term ecological analysis of land-use and floristic diversity in the transition from traditional to modern land-use management in the time A.D. 1800-2008 in southern Sweden. We use the Regional Estimates of Vegetation Abundance from Large Sites (REVEALS) model to quantify land-cover changes on a regional scale at 20-year intervals, based on the fossil pollen record. Floristic richness and evenness are estimated using palynological richness and the Shannon index applied to the REVEALS output, respectively. We identified a transition period of 60 years between 1880 and 1940 when the total tree cover increased and the tree composition changed from deciduous to coniferous dominance. Within the shrinking area of open land, arable land taxa expanded, while the number and coverage of herbs in the remaining grasslands decreased. The succession from open grasslands to more tree-covered habitats initially favoured palynological richness, which reached its highest values during the first 40 years of the transition period. The highest REVEALS-based evenness was recorded in the time of traditional land-use and at the beginning of the transition period, reflecting higher habitat diversity at these time intervals. Our results support a more dynamic ecosystem management that changes between traditional land-use and phases of succession (\40 years) to promote floristic diversity. We have developed and applied a palaeoecological methodology that contributes realistic estimates to be used in ecosystem management

Testing the effect of site selection and parameter setting on REVEALS-model estimates of plant abundance using th Czech Quaternary Palynological database

International audiencetypes, PFTs) is used in the LANDCLIM project to assess the effect of human-induced land-cover change on past climate in NW Europe. Using the Czech Quaternary Pollen Database, this case study evaluates the extent to which selection of data and input parameters for the REVEALS model applications would affect reconstruction outcomes. The REVEALS estimates of PFTs (grid-cell based REVEALS PFT estimates, GB REVEALS PFT-s) are calculated for five time windows of the Holocene using fossil pollen records available in each 1°×1°grid cell of the Czech Republic. The input data and parameters selected for testing are: basin type and size, number of 14C dates used to establish the chronology of the pollen records, number of taxa, and pollen productivity estimates (PPE). We used the Spearman correlation coefficient to test the hypothesis that there is no association between GB REVEALS PFT-s using different data and parameter inputs. The results show that differences in the basin size and type, number of dates, number and type of taxa (entomophilous included or not), and PPE dataset do not affect the rank orders of the GB REVEALS PFT-s significantly, except for the cases when entomophilous taxa are included. It implies that, given careful selection of data and parameter and interpretation of results, REVEALS applications can use pollen records from lakes and bogs of different sizes together for reconstruction of past land cover at the regional to sub-continental spatial scales for purposes such as the study of past land cover-climate interactions. Our study also provides useful criteria to set up protocols for data compilation REVEALS applications of this kind

Two hundred years of land-use change in the South Swedish Uplands : comparison of historical map-based estimates with a pollen-based reconstruction using the landscape reconstruction algorithm

International audienceLong-term records of environmental history at decadal to millennial timescales enable an assessment of ecosystem variability and responses to past anthropogenic disturbances and are fundamental for the development of environmental management strategies. This study examines the local variability of land-use history in the South Swedish Uplands over the last 200 years based on pollen records from three lake-sediment successions. Temporal changes in the proportional cover of 14 plant taxa were quantified as percentages using the landscape reconstruction algorithm (LRA). The LRA-based estimates of the extent of four land-use categories (cropland, meadows/grassland, wetland, outland/woodland) were compared to corresponding estimates based on historical maps and aerial photographs from AD 1769–1823, 1837–1895, 1946 and 2005. Although the LRA approach tends to overestimate grassland cover by 10–30 % for the two earliest time periods, the reconstructed vegetation composition is generally in good agreement with estimates based on the historical records. Subsequently, the LRA approach was used to reconstruct the 200-year history of local land-use dynamics at 20-year intervals around two small lakes. The qualitative assessment of difference approach , which requires fewer assumptions and parameters than LRA for objective evaluation of between-site differences in plant abundances, provides consistent results in general. Significant differences exist in the land-use history between the sites. Local catchment characteristics, such as soil conditions and wetland cover, appear important for the development of human impact on the landscape. Quantifi-cations of past vegetation dynamics provide information on the amplitude, frequency and duration of the land-use changes and their effects on terrestrial and aquatic ecosystems , and should be taken into account when nature conservation strategies are developed

Pollen productivity estimates and relevant source area of pollen for selected plant taxa in a pasture woodland landscape of the Jura Mountains (Switzerland)

Relevant source area of pollen (RSAP) and pollen productivity for 11 key taxa characteristic of the pasture woodland landscape of the Jura Mountains, Switzerland, were estimated using pollen assemblages from moss polsters at 20 sites. To obtain robust pollen productivity estimates (PPEs), we used vegetation survey data at a fine spatial-resolution (1 x 1 m(2)) and randomized locations for sampling sites, techniques rarely used in palynology. Three Extended R value (ERV) submodels and three distance-weighting methods for plant abundance calculation were applied. Different combinations of the submodels and distance-weighting methods provide slightly different estimates of RSAP and PPEs. Although ERV submodel 1 using 1/d (d = distance in meters) best fits the dataset, PPE values for heavy pollen types (e.g. Abies) were sensitive to the method used for distance-weighting. Taxon-specific distance-weighting methods, such as Prentice's model, emphasize the intertaxonomic differences in pollen dispersal and deposition, and are thus theoretically sound. For the dataset obtained in this project, Prentice's model was more appropriate than other distance-weighting methods to estimate PPEs. Most of the taxa have PPEs equal to (Fagus, Plantago media and Potentilla-type), or higher (Abies, Picea, Rubiaceae and Trollius europaeus) than Poaceae (PPE = 1). Acer, Cyperaceae, and Plantago montana-type are low pollen producers. This set of PPEs will be useful for reconstructing heterogeneous, mountainous pasture woodland landscapes from fossil pollen records. The RSAP for moss polsters in this semi-open landscape region is ca. 300 m

Regulatory elements coordinating initiation of chromosome replication to the Escherichia coli cell cycle

Escherichia coli coordinates replication and division cycles by initiating replication at a narrow range of cell sizes. By tracking replisomes in individual cells through thou-sands of division cycles in wild-type and mutant strains, we were able to compare the relative importance of previously described control systems. We found that accurate triggering of initiation does not require synthesis of new DnaA. The initiation size increased only marginally as DnaA was diluted by growth after dnaA expression had been turned off. This suggests that the conversion of DnaA between its active ATP -and inactive ADP-bound states is more important for initiation size control than the total free concentration of DnaA. In addition, we found that the known ATP/ADP converters DARS and datA compensate for each other, although the removal of them makes the initiation size more sensitive to the concentration of DnaA. Only disruption of the regulatory inactivation of DnaA mechanism had a radical impact on replication initiation. This result was corroborated by the finding that termination of one round of replication correlates with the next initiation at intermediate growth rates, as would be the case if RIDA-mediated conversion from DnaA-ATP to DnaA-ADP abruptly stops at termination and DnaA-ATP starts accumulating

The association between cognitive function and self-care in patients with chronic heart failure

Background: Self-care requires that patients learn to care for themselves. Cognitive impairment and depression can decrease the ability and interest in performing self-care. The objectives were to explore the association between cognitive function and self-care in heart failure patients, and to examine if this association was moderated by symptoms of depression. Methods: This cross-sectional study included 105 heart failure patients in NYHA II-IV, median age 72 years. Self-care was measured with the European Heart Failure Self-Care Behavior Scale, cognitive function with a neuropsychological battery, and depressive symptoms were measured with the Patient Health Questionnaire. The associations between the study variables were examined with multiple regression analyses. Results: Psychomotor speed was the only cognitive dimension significantly associated with self-care. The association between psychomotor speed and self-care was not moderated by symptoms of depression. Conclusions: Deficits in psychomotor speed have implications for how patients should be educated and supported to perform self-care

Recent brownification of South Swedish lake waters – an effect of climate change or land use?

International audienceDissolved organic carbon (DOC) content, especially terrestrial humic matter (DHM), and water colour of many lakes and streams have increased substantially during the last decades (Evans et al. 2004, Roulet and Moore 2006). Brownification not only reduces the quality of these waters as drinking water supplies and for recreational purposes, but lake biodiversity is also expected to be effected. The aim of this project is to evaluate the potential underlying causes of the recent brownification of South Swedish lakes. Amultiproxy approach is applied (fig 3.) for reconstruct on of the biogeochemical and biological changes within selected lakes, and the vegetation/land use changes within their catchments for the past c. 1000 years. Here we present the study area, main methods, preliminary results and links to Fredh et al. projec

Farm establishment, abandonment and agricultural practices during the last 1,300 years: a case study from southern Sweden based on pollen records and the LOVE model

International audienc