1,114 research outputs found
Ordnung und Unordnung. Hartmut von Hentig zum 23. September 1985
No full textBecker G, Becker H, Huber L, eds. Ordnung und Unordnung. Hartmut von Hentig zum 23. September 1985. Weinheim, Basel : Beltz ; 1985
37 years of permanent plot research within a calcareous beech forest – a time series 1980–2001–2016
No full textIm Rahmen eines Ökosystem-Forschungsprojektes in der Nähe von Göttingen wurden 1980 auf fest markierten Flächen eines artenreichen Kalkbuchenwaldes (Hordelymo-Fagetum lathyretosum) 41 Vegetationsaufnahmen gemacht, in den Jahren 2001 und 2016 wiederholt und nun als Zeitreihe verglichen. In allen Schichten wurden signifikante Veränderungen von Struktur und Artenzusammensetzung festgestellt. Nach hohen Deckungsgraden einzelner krautiger Arten wurden 1980 verschiedene Dominanztypen (DT) unterschieden. Die unterschiedliche Zuordnung der 41 Aufnahmen im Zeitverlauf zu diesen DT wies bereits auf strukturelle Veränderungen hin. Vor allem der zunächst bestimmende Mercurialis perennis-DT hat sich zum Allium ursinum- oder Anemone nemorosa-DT hin verschoben (Tab. 1–2). Im Gesamtvergleich (Tab. 3–4) zeigen sich weitere strukturelle und floristische Veränderungen. Die von Fagus sylvatica beherrschte Baumschicht entwickelte ein dichteres Kronendach. Die Einzäunung der gesamten Untersuchungsfläche leitete wegen Ausschluss des Wildverbisses die Ausbildung einer Strauchschicht, vorwiegend aus Jungbäumen ein. Die statistisch ausgewerteten Veränderungen in der Krautschicht ergaben Artengruppen unterschiedlicher Dynamik: 15 Gewinner, 20 Verlierer und 18 konstante Arten. Ein Literaturvergleich zeigt teilweise sehr ähnliche Ergebnisse (Tab. 5). Die Gesamtartenzahl aller Flächen nahm von 1980 bis 2016 von 63 auf 58 ab. Funktionelle Eigenschaften (Lebensformen, Blattausdauer; Abb. 2–3) zeigen nur geringe Veränderungen. Fast alle Krautigen gehören zu Artengruppen mit starker Waldbindung (Abb. 3). Die Auswertung ökologischer Zeigerwerte (Abb. 4) lässt die Entwicklung zu einem stärker schattigen und luftfeuchten Mikroklima vermuten. Eine Gradientenanalyse (NMDS) zeigt ebenfalls deutliche zeitliche Veränderungen (Abb. 5). Als Hauptursache der Vegetationsveränderungen wird die langzeitige Forstgeschichte angenommen, d. h. der Übergang von extensiver Mittelwald- zu Hochwaldwirtschaft innerhalb von etwa 100 Jahren. Der Klimawandel ist derzeit vor allem in der Verfrühung und Verlängerung der Frühlings-Phänophasen erkennbar und hat u. a. die Frühlingsgeophyten gefördert. Die oft beschriebenen Eutrophierungswirkungen durch atmosphärische N-Einträge scheinen hier hingegen keine größere Rolle zu spielen. Trotz sich wandelnder Umweltbedingungen in fast 40 Jahren hat sich die grundlegende Struktur und Artenzusammensetzung des Bestandes bisher kaum verändert.In 1980, within an ecosystem research project nearby Göttingen 41 vegetation relevés have been made on permanently marked plots within a calcareous beech forest (Hordelymo-Fagetum lathyretosum). These relevés have been repeated in 2001 and 2016 and were now analysed as a time series. In all vegetation layers significant changes could be found. In 1980 different dominance types (DT) were defined by high coverage of single plant species of the herb layer. The different allocation of the relevés to these DT over time indicated structural changes. Especially the 1980 prevalent Mercurialis perennis-DT shifted to the Allium ursinum- or Anemone nemorosa-DT (Table 1–2). The total comparison (Table 3–4) showes further structural and floristic changes. The tree layer, dominated by Fagus sylvatica, developed a denser canopy. Fencing of the total research area initiated the establishment of a shrub layer, mainly consisting of young trees. The statistically evaluated changes in the herb layer resulted in species groups of different dynamics: 15 winners, 20 losers and 18 constant species. Comparisons with literature data show partly similar results (Table 5). The total species number of all relevés decreased from 63 to 58. Functional traits (life form, leave longevity; Fig. 2–3) changed only slightly. Almost all herbaceous plants have a strong forest affinity (Fig. 3). The evaluation of ecological indicator values (Fig. 4) suggests the development of a more shady and humid microclimate. An ordination (NMDS; Fig. 5) also showes a clear floristic change over time. As the main driver for vegetation changes the forest history is considered, i.e. the change from a coppice-with-standards to high forest management since about 100 years. Climate change is especially recognizable by earlier beginning and longer lasting of spring phenophases, among others promoting spring geophytes. The often described eutrophication by atmospheric nitrogen input, however, seems to be not very important. Despite of changing ecological conditions within almost 40 years no basic structural-floristic changes can be observed
Vegetation response to high concentrations of heavy metals in the Harz Mountains, Germany
No full textHeavy metal content is assumed to be the most important edaphic factor determining vegetation composition on contaminated soil. We compared the relationships between vegetation composition and heavy metal content at 23 mining sites in the Hart Mountains in Germany with those of other soil environmental factors. 120 releves were assigned to the Armerierum halleri which was subdivided into three subassociations, A. cladonietosum, A. typicum and A. achilletosum. Within each of the latter subassociations a Typical variant and a Cardaminopsis halleri variant were classified. The first axis of a DCA was positively correlated with Ellenberg's indicator values for soil reaction, nitrogen and moisture, and the concentration of calcium, and negatively with the concentration of copper and the proportion of stones, indicating that these variables were most important for vegetation differentiation. Soil concentrations of lead and exchangeable zinc did not differ significantly between the communities, while concentrations of copper and water-soluble zinc were highest in the A. cladonietosum and lowest in the A. achilletosum. Ellenberg's indicator values for nitrogen indicate poorest nutrient conditions in the A. cladonietosum where soil depth was especially low and richest conditions in the A. achilletosum where soil depth was higher. Logistic regression showed that the presence of the metallicolous Minuartia verna subsp. hercymica increased with the concentration of soluble zinc in the soil, while the presence of Armeria maritima subsp. halleri and Cardaminopsis halleri decreased with increasing concentration of copper. Armeria was furthermore strongly negatively affected by altitude, while Cardaminopsis was positively affected by soil depth and moisture. Silene vulgaris var. humilis was neither influenced by heavy metals nor by other environmental factors. A comparison of the recent number of slag heaps with those listed in a 75 year old study demonstrates a strong decline of these habitats and their specific vegetation due to both human destruction and natural succession. - We conclude that heavy metals are by far not the only factor controlling vegetation on metalliferous soils. At the mining sites investigated vegetation is also strongly controlled by low soil fertility
Young and old steppe-like grasslands in the "Badra Lehde-Grosser Eller" Reserve (Kyffhauser Mountains, central Germany)
No full textYoung and old steppe-like grasslands in the "Badra Lehde-Grosser Eller" Reserve (Kyffhauser Mountains, central Germany) The steppe-like grasslands of the "Badra Lehde - Grosser Eller" Reserve are here for the first time analysed and described in detail. 156 original releves were classified using cluster analysis into seven associations and two communities without rank within the alliances Alysso-Sedion, Seslerio-Festucion pallentis, Festucion valesiacae, Xerobromion, and Cirsio-Brachypodion. Old aerial images show that the communities without rank represent young steppe-like grasslands growing on former arable land whereas the associations mainly represent old steppe-like grasslands. The first floristic gradient resulting from NMDS is most strongly explained by variables representing temperature and water availability of the soil. The second floristic gradient can be explained by former arable land use. Old steppe-like grasslands contain significant more endangered plant species than young grasslands on former arable land, but total species number does not differ between both grassland types. CSR strategy analysis indicates higher importance of C strategy in one community on former arable land but weak differences between the other syntaxa. Xerobromion communities are the most species rich and contain the highest number of endangered plant species. One of the communities without rank on former arable land is moderately species rich, while the other is the most species poor of all communities. Species richness of vascular plants is positively correlated with soil depth, cover of herb layer and the Ellenberg indicator value for soil reaction and negative with the indicator value for temperature. Our study shows that the "Badra Lehde-Grosser Eller" Reserve is important for dry grassland conservation due to the general plant species richness and high numbers of species and communities that are rare and endangered
Young and old steppe-like grasslands in the "Badra Lehde-Grosser Eller" Reserve (Kyffhauser Mountains, central Germany)
No full textYoung and old steppe-like grasslands in the "Badra Lehde-Grosser Eller" Reserve (Kyffhauser Mountains, central Germany) The steppe-like grasslands of the "Badra Lehde - Grosser Eller" Reserve are here for the first time analysed and described in detail. 156 original releves were classified using cluster analysis into seven associations and two communities without rank within the alliances Alysso-Sedion, Seslerio-Festucion pallentis, Festucion valesiacae, Xerobromion, and Cirsio-Brachypodion. Old aerial images show that the communities without rank represent young steppe-like grasslands growing on former arable land whereas the associations mainly represent old steppe-like grasslands. The first floristic gradient resulting from NMDS is most strongly explained by variables representing temperature and water availability of the soil. The second floristic gradient can be explained by former arable land use. Old steppe-like grasslands contain significant more endangered plant species than young grasslands on former arable land, but total species number does not differ between both grassland types. CSR strategy analysis indicates higher importance of C strategy in one community on former arable land but weak differences between the other syntaxa. Xerobromion communities are the most species rich and contain the highest number of endangered plant species. One of the communities without rank on former arable land is moderately species rich, while the other is the most species poor of all communities. Species richness of vascular plants is positively correlated with soil depth, cover of herb layer and the Ellenberg indicator value for soil reaction and negative with the indicator value for temperature. Our study shows that the "Badra Lehde-Grosser Eller" Reserve is important for dry grassland conservation due to the general plant species richness and high numbers of species and communities that are rare and endangered
Studieren: diszipliniert oder undiszipliniert?
No full textHuber L. Studieren: diszipliniert oder undiszipliniert? In: Becker G, ed. Ordnung und Unordnung : Hartmut von Hentig zum 23. September 1985. Weinheim: Beltz; 2005: 83-88
Brenntechnologie für Geschirr unter besonderer Berücksichtigung des Glattbrands von Porzellan Flachware im Schnellbrandofen
No full textvon Dipl.-Ing. Friedherz Hartmut Becke
Sozialversicherungen in Deutschland
No full textSusanne Becker, Peter Friedrich, Hartmut Reiners, Rainer Schlegel. Friedrich-Ebert-Stiftung, Büro BeijingElectronic ed.: Beijing ; Bonn : FES, 2007. - Text in German and Chinese languag
Effects of neurofeedback on the dysregulation profile in children with ADHD: SCP NF meets SDQ-DP – a retrospective analysis
No full textKosmos, Volk und Offenbarung – Ideologie und Ideologievermittlung in Gertrud Prellwitz’ Drude-Romanen
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