157 research outputs found
Vegetation change in meso-xeric grasslands of the Swiss Jura Mts. over 40 years
Meso-xeric grasslands have declined sharply in Central Europe during the last century. These spe-cies-rich habitats are threatened by intensification or abandonment of agricultural use, eutrophication, climate change and landscape fragmentation. However, different studies in various regions of Central Europe are inconsistent in their findings about degree and direction of changes. We thus resurveyed the historical vegetation plots of the alliance Mesobromionin the Swiss Jura Mts. In 2020, we re-sampled 28 quasi-permanent vegetation plots originally recorded in 1980 to quantify potential vegetation change. Frequency of individual species, species diversity, 11 ecological indicator values and four functional traits, as well as the presence of diagnostic species of phytosociological alliances, were analysed. Further, a habitat classification and detrended correspondence analysis (DCA) were also performed. Species richness, indicator values for light availability and temperature, seed dispersal by animals and seed persistence had significantly decreased by 2020. Conversely, ecological indicator values for nutrient availability and soil moisture as well as community-weighted means for seed mass and canopy height had significantly increased. There were significantly fewer ruderal species, stress-tolerators, therophytes and herbaceous chamaephytes in 2020. In contrast, highly competitive species and hemicryptophytes had increased. Together, these findings indicate an increase in productivity over time. There were fewer specialized species in 2020 than in 1980, indicating a homogenization of the vegetation and a shift towards nutrient-rich pastures and meadows. The shift towards a later succession-al stage might indicate reduced grazing disturbance. Most of these sites are currently not included in an agri-environmental scheme. Partial differences of our findings from those reported elsewhere in Central Europe highlight the importance of regionally adapted conservation strategies in order to stop biodiver-sity loss in meso-xeric grasslands
Tracer Survey in the Cape Verde Region Traceraufnahme in der Kapverdenregion Cruise No. 10, Leg 1 October 31 â December 06, 2008 Ponta Delgada (Portugal) â Mindelo (Cape Verde Islands)
The research cruise MSM10/1 was extremely successful. All programs were able to collect high quality data and the anticipated goals of the expedition were fully met. We have been able to carry out the first comprehensive survey of a tracer release in the Guinea Upwelling region (GUTRE) roughly seven month after the tracer was released at 8°N 23°W in April 2008. We have estimated that a total of 40% of the tracer was found during this cruise. While the horizontal spreading and mixing was larger than anticipated, the vertical extent of the tracer found was small. The low vertical tracer spreading rate estimates are supported by the micro structure profile data. The extensive survey of the upper 1000m of the oxygen minimum zone (OMZ) allowed comparing our sections with several previous surveys. We found that the lowest oxygen values in the core of the OMZ have dropped at record low values below 40 Όmol/kg. The preliminary findings from the trace metal work focused on Fe ligand measurements shows a slight higher excess ligand concentration in the surface (50m) for three stations. The two other stations show a slight decrease at this depth. A large number of biochemical samples were taken and were analyzed in Kiel for DNA and RNA diversity. The tracer release experiment provided an ideal environment for repeated biochemical sampling in the same water mass
Organic carbon production, mineralization and preservation on the Peruvian margin
Carbon cycling in Peruvian margin sediments (11° S and 12° S) was examined at 16 stations from 74 m on the inner shelf down to 1024 m water depth by means of in situ flux measurements, sedimentary geochemistry and modeling. Bottom water oxygen was below detection limit down to ca. 400 m and increased to 53 ÎŒM at the deepest station. Sediment accumulation rates and benthic dissolved inorganic carbon fluxes decreased rapidly with water depth. Particulate organic carbon (POC) content was lowest on the inner shelf and at the deep oxygenated stations (< 5%) and highest between 200 and 400 m in the oxygen minimum zone (OMZ, 15â20%). The organic carbon burial efficiency (CBE) was unexpectedly low on the inner shelf (< 20%) when compared to a global database, for reasons which may be linked to the frequent ventilation of the shelf by oceanographic anomalies. CBE at the deeper oxygenated sites was much higher than expected (max. 81%). Elsewhere, CBEs were mostly above the range expected for sediments underlying normal oxic bottom waters, with an average of 51 and 58% for the 11° S and 12° S transects, respectively. Organic carbon rain rates calculated from the benthic fluxes alluded to a very efficient mineralization of organic matter in the water column, with a Martin curve exponent typical of normal oxic waters (0.88 ± 0.09). Yet, mean POC burial rates were 2â5 times higher than the global average for continental margins. The observations at the Peruvian margin suggest that a lack of oxygen does not affect the degradation of organic matter in the water column but promotes the preservation of organic matter in marine sediments
A benthic-pelagic nitrogen budget for the continental margin of the Peruvian oxygen minimum zone
Sampling multi-scale and multi-taxon plant diversity data in the subalpine and alpine habitats of Switzerland : report on the 14th EDGG Field Workshop
The 14th EDGG Field Workshop took place from the 4th to the 14th of September 2020 in Switzerland, and was devoted to the vegetation of open habitats in the subalpine and alpine zones. In total, 26 EDGG Biodiversity Plots (nested plots with grain sizes of 0.0001 to 100 mÂČ) were sampled in different open habitat types (grasslands, heathlands, screes, snowbeds, fens) in three regions of Switzerland, both over acidic and base-rich bedrock. Additionally, three normal plots of 10 mÂČ were sampled in high-elevation Festuco-Brometea stands in Zermatt. Across all grain sizes, stands showed 10â25% higher means and 50â94% higher maxima for total richness of vascular plants, terricolous bryophytes and lichens compared with data from the 12th EDGG Field Workshop in dry and semi-dry grasslands of the central valleys of the Swiss Alps. We found outstanding preliminary maxima of total richness of 61, 109 and 163 species in 1, 10 and 100 mÂČ respectively, in an unused alpine grassland over limestone (Seslerion). Both particularly variable and partly extremely rich was the bryophyte and lichen flora of the analysed stands, with up to 33 bryophyte and 22 lichen species in 10-mÂČ plots. We report the liverwort Cephaloziella dentata as new for Switzerland, found in a thermophilous subalpine heathland at Alp Glivers, Surselva, Grisons. Overall, our preliminary data suggest that some of the sampled subalpine and alpine habitats are among the most species-rich communities at small scales if bryophytes and lichens are also considered. Based on this finding, we recommend that these two taxonomic groups be more regularly included in surveying and particularly in monitoring programs for vegetation. The Scientific Report is supplemented by a photo diary that provides impressions of work and life during the Field Workshop
Determination of habitat requirements of the glacial relict Nuphar pumila as basis for successful (re-)introductions
Nuphar pumila is a glacial relict, which is nowadays rare throughout Europe and red-listed in most European regions. In Switzerland only three autochthonous populations and one population of the hybrid with N. lutea (N. Ăspenneriana) have survived to date, one of them in the canton of Zurich. To protect this species regionally, the canton of Zurich has commissioned the ex situ propagation of speci-mens, which then had been introduced to 37 water bodies in protected areas, including one known former site. Since only about 10% of these introductions had been successful, there was a wish to identify causes of this lack of success. To this end, we compared the vegetation and physical-chemical parameters of the four natural sites in Switzerland with the successful and unsuccessful introduction sites. Additionally, for a subset of sites, we assessed diatom genus composition as a proxy of water quality. Moreover, we derived vegetation plots of N. pumila and N. lutea from across Europe from the European Vegetation Archive (EVA) to compare their site conditions, using mean ecological indicator values and bioclimatic variables of the localities. We found that inside Switzerland the main differences were between the natural sites and all introduction sites, while successful and unsuccessful introduction sites hardly differed in the determined parameters. Natural sites had cooler water with lower magnesi-um content, and according to mean ecological indicator values, also lower nutrient status. The diatom data, though limited in amount, point into the same direction. The EVA data demonstrate that stands of N. pumila are mainly more oligotrophic, but also cooler and more acidic than those of N. lutea. We could not find any factor that explains the success vs. lack of success of plantations of N. pumila in multiple sites in the canton of Zurich, but our results rather indicate that due to the relatively warm climate, the high atmogenic nitrogen input and the predominantly base-rich bedrock, the sites in the canton are generally not particularly well suited for N. pumila. We consider it therefore more promising to protect and possibly (re-)introduce N. pumila in other cantons with higher elevation, base-poor bedrock and lower atmogenic nitrogen input
Neue Daten und Empfehlungen der Arbeitsgruppe âNachwuchsâ im Verein fĂŒr Socialpolitik
Dieser Beitrag ist mit Zustimmung des Rechteinhabers (De Gruyter) frei zugĂ€nglich.Der Verein fĂŒr Socialpolitik hat zur Bearbeitung seines Schwerpunktthemas âNachwuchsâ fĂŒr die Dauer der Kalenderjahre 2021â2022 eine Arbeitsgruppe eingerichtet â im Folgenden: AG Nachwuchs â, deren Aufgabe das Vorlegen eines umfassenden Berichts zur Situation der VWL-Promovierenden und -PostDocs im DACH-Raum ist. GestĂŒtzt auf Datenerhebungen und strukturierte Interviews formuliert die AG Nachwuchs in diesem Bericht zwei Empfehlungen, jeweils eine fĂŒr den Doc- und den PostDoc-Bereich. Sie empfiehlt im PostDoc-Bereich, dass die FakultĂ€ten bzw. verwandte VWL-Einrichtungen den Ăbergang zu Tenure-Track beschleunigen und ihn durch eine systematische Planung der ZahlenverhĂ€ltnisse zwischen den Karrierestufen bei ihrem wissenschaftlichen Personal begleiten. Dadurch sollen bessere Karriereperspektiven erreicht werden. Sowohl die befragten NachwuchskrĂ€fte als auch die befragten Professor:innen und Programmleitungen betonen die Thematik der Stellenperspektiven stark. Im Doc-Bereich dokumentieren die Erhebungsdaten eine ĂŒberraschend geringe Zufriedenheit der VWL-Promovierenden mit der Betreuungssituation durch die Professorenschaft. Die AG Nachwuchs empfiehlt daher eine höhere Betreuungsdichte und eine stĂ€rkere Vernetzung von Promovierenden. Weitere Hilfestellungen fĂŒr Promovierende können in Mehrfach- oder Teambetreuungen sowie in der Bereitstellung von Informationen ĂŒber die Vielfalt möglicher Karrierewege bestehen.Peer Reviewe
GrassPlot v. 2.00 â first update on the database of multi-scale plant diversity in Palaearctic grasslands
Abstract: GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). Following a previous Long Database Report (Dengler et al. 2018, Phyto- coenologia 48, 331â347), we provide here the first update on content and functionality of GrassPlot. The current version (GrassPlot v. 2.00) contains a total of 190,673 plots of different grain sizes across 28,171 independent plots, with 4,654 nested-plot series including at least four grain sizes. The database has improved its content as well as its functionality, including addition and harmonization of header data (land use, information on nestedness, structure and ecology) and preparation of species composition data. Currently, GrassPlot data are intensively used for broad-scale analyses of different aspects of alpha and beta diversity in grassland ecosystems
Controls on redox-sensitive trace metals in the Mauritanian oxygen minimum zone
The availability of the micronutrient iron (Fe) in surface waters determines primary production, N2 fixation, and microbial community structure in large parts of the world's ocean, and thus it plays an important role in ocean carbon and nitrogen cycles. Eastern boundary upwelling systems and the connected oxygen minimum zones (OMZs) are typically associated with elevated concentrations of redox-sensitive trace metals (e.g., Fe, manganese (Mn), and cobalt (Co)), with shelf sediments typically forming a key source. Over the last 5 decades, an expansion and intensification of OMZs has been observed and this trend is likely to proceed. However, it is unclear how trace-metal (TM) distributions and transport are influenced by decreasing oxygen (O2) concentrations. Here we present dissolved (d; 0.2â”m) TM data collected at seven stations along a 50âkm transect in the Mauritanian shelf region. We observed enhanced concentrations of Fe, Co, and Mn corresponding with low O2 concentrations (<50â”molâkgâ1), which were decoupled from major nutrients and nutrient-like and scavenged TMs (cadmium (Cd), lead (Pb), nickel (Ni), and copper (Cu)). Additionally, data from repeated station occupations indicated a direct link between dissolved and leachable particulate Fe, Co, Mn, and O2. An observed dFe (dissolved iron) decrease from 10 to 5ânmolâLâ1 coincided with an O2 increase from 30 to 50â”molâkgâ1 and with a concomitant decrease in turbidity. The changes in Fe (Co and Mn) were likely driven by variations in their release from sediment pore water, facilitated by lower O2 concentrations and longer residence time of the water mass on the shelf. Variations in organic matter remineralization and lithogenic inputs (atmospheric deposition or sediment resuspension; assessed using Al as indicator for lithogenic inputs) only played a minor role in redox-sensitive TM variability. Vertical dFe fluxes from O2-depleted subsurface-to-surface waters (0.08â13.5â”molâmâ2âdâ1) driven by turbulent mixing and vertical advection were an order of magnitude larger than atmospheric deposition fluxes (0.63â1.43â”molâmâ2âdâ1; estimated using dAl inventories in the surface mixed layer) in the continental slope and shelf region. Benthic fluxes are therefore the dominant dFe supply to surface waters on the continental margins of the Mauritanian upwelling region. Overall, our results indicated that the projected future decrease in O2 concentrations in OMZs may result in increases in Fe, Mn, and Co concentrations
The spinal cord injury-induced immune deficiency syndrome: results of the SCIentinel study
Infections are prevalent after spinal cord injury (SCI), constitute the main cause of death and are a rehabilitation confounder associated with impaired recovery. We hypothesize that SCI causes an acquired lesion-dependent (neurogenic) immune suppression as an underlying mechanism to facilitate infections. The international prospective multicentre cohort study (SCIentinel; protocol registration DRKS00000122; n = 111 patients) was designed to distinguish neurogenic from general trauma-related effects on the immune system. Therefore, SCI patient groups differing by neurological level, i.e. high SCI [thoracic (Th)4 or higher]; low SCI (Th5 or lower) and severity (complete SCI; incomplete SCI), were compared with a reference group of vertebral fracture (VF) patients without SCI. The primary outcome was quantitative monocytic Human Leukocyte Antigen-DR expression (mHLA-DR, synonym MHC II), a validated marker for immune suppression in critically ill patients associated with infection susceptibility. mHLA-DR was assessed from Day 1 to 10 weeks after injury by applying standardized flow cytometry procedures. Secondary outcomes were leucocyte subpopulation counts, serum immunoglobulin levels and clinically defined infections. Linear mixed models with multiple imputation were applied to evaluate group differences of logarithmic-transformed parameters. Mean quantitative mHLA-DR [ln (antibodies/cell)] levels at the primary end point 84â
h after injury indicated an immune suppressive state below the normative values of 9.62 in all groups, which further differed in its dimension by neurological level: high SCI [8.95 (98.3% confidence interval, CI: 8.63; 9.26), n = 41], low SCI [9.05 (98.3% CI: 8.73; 9.36), n = 29], and VF without SCI [9.25 (98.3% CI: 8.97; 9.53), n = 41, P = 0.003]. Post hoc analysis accounting for SCI severity revealed the strongest mHLA-DR decrease [8.79 (95% CI: 8.50; 9.08)] in the complete, high SCI group, further demonstrating delayed mHLA-DR recovery [9.08 (95% CI: 8.82; 9.38)] and showing a difference from the VF controls of -0.43 (95% CI: -0.66; -0.20) at 14 days. Complete, high SCI patients also revealed constantly lower serum immunoglobulin G [-0.27 (95% CI: -0.45; -0.10)] and immunoglobulin A [-0.25 (95% CI: -0.49; -0.01)] levels [ln (g/l Ă 1000)] up to 10 weeks after injury. Low mHLA-DR levels in the range of borderline immunoparalysis (below 9.21) were positively associated with the occurrence and earlier onset of infections, which is consistent with results from studies on stroke or major surgery. Spinal cord injured patients can acquire a secondary, neurogenic immune deficiency syndrome characterized by reduced mHLA-DR expression and relative hypogammaglobulinaemia (combined cellular and humoral immune deficiency). mHLA-DR expression provides a basis to stratify infection-risk in patients with SCI
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