2,283 research outputs found
Impact of tree species on nutrient and light availability: evidence from a permanent plot study of old-field succession
No full textThis paper compares vegetation composition, light availability, carbon and nutrient pools and Ellenberg indicator values among four old-field successional permanent plots that have received an initial treatment (ploughing, herbicide or sterilisation) prior to being left undisturbed in 1969, a second set of six plots received additional treatments (continued ploughing or mulching until 1982). On all plots species rich pioneer forests developed. Vegetation still varies among plots with different initial treatments: Sterilised plots can be distinguished from the others by dominance of Betula pendula, ploughed plots by Fraxinus excelsior, whereas herbicide-treated plots are intermediate with proportions of both species. By affecting light availability at the ground, tree species in turn influences ground vegetation and soil properties. Light availability turned out to be the dominant factor determining the composition of the vegetation in old-field succession
The relationship between soil seed bank, above-ground vegetation and disturbance intensity on old-field successional permanent plots
No full textQuestions How does disturbance and successional age influence richness, size and composition of the soil seed bank? What is the potential contribution of the soil seed bank to the plant community composition on sites differing in their successional age or disturbance intensity? Location Experimental Botanical Garden of Gottingen University, central Germany. Methods Above-ground vegetation and soil seed bank were studied on formerly arable fields in a 36-year-old permanent plot study with five disturbance intensities, ranging from yearly ploughing via mowing to long-term uninterrupted succession. We compared species compositions, seed densities and functional features of the seed bank and above-ground vegetation by using several methods in parallel. Results The seed bank was mainly composed of early successional species typical of strongly disturbed habitats. The difference between seed bank composition and above-ground vegetation decreased with increasing disturbance intensity. The species of greatest quantitative importance in the seed bank was the non-native forb Solidago canadensis. Conclusions The ability of a plant community to regenerate from the soil seed bank dramatically decreases with increasing time since abandonment (successional age) and with decreasing disturbance intensity. The present study underlines that plant species typical of grasslands and woodlands are limited by dispersal capacity, owing to low capacity for accumulation of seeds in the soil and the fact that most species do not build up persistent seed banks. Rare and target species were almost absent from the seed bank and will, after local elimination, depend on reintroduction for continuation of their presence
The relationship between soil seed bank, above-ground vegetation and disturbance intensity on old-field successional permanent plots
No full textQuestions How does disturbance and successional age influence richness, size and composition of the soil seed bank? What is the potential contribution of the soil seed bank to the plant community composition on sites differing in their successional age or disturbance intensity? Location Experimental Botanical Garden of Gottingen University, central Germany. Methods Above-ground vegetation and soil seed bank were studied on formerly arable fields in a 36-year-old permanent plot study with five disturbance intensities, ranging from yearly ploughing via mowing to long-term uninterrupted succession. We compared species compositions, seed densities and functional features of the seed bank and above-ground vegetation by using several methods in parallel. Results The seed bank was mainly composed of early successional species typical of strongly disturbed habitats. The difference between seed bank composition and above-ground vegetation decreased with increasing disturbance intensity. The species of greatest quantitative importance in the seed bank was the non-native forb Solidago canadensis. Conclusions The ability of a plant community to regenerate from the soil seed bank dramatically decreases with increasing time since abandonment (successional age) and with decreasing disturbance intensity. The present study underlines that plant species typical of grasslands and woodlands are limited by dispersal capacity, owing to low capacity for accumulation of seeds in the soil and the fact that most species do not build up persistent seed banks. Rare and target species were almost absent from the seed bank and will, after local elimination, depend on reintroduction for continuation of their presence
Lightning activity in the regions of MSC over Czechia
No full textTitle: Lightning activity in the regions of MCS over Czechia Author: Michaela Arnoštová Department: Department of Atmospheric Physics Supervisor: Mgr. Michal Žák, Ph.D., Department of Atmospheric Physics Abstract: This bachelor's thesis deals with lighting activity and its detection in mesoscale convective systems (MCS) over the Czech Republic and adjacent areas. The first part describes the formation and development of MCS, electrical charge distribution inside clouds, types of lightning and their detection. The second part is devoted to five specific MCS that occurred in different time periods. Data of lightning detection network (LINET) are used to describe the characteristics of lightning, especially their temporal and spatial development, occurrence of different types of lightning and development of their current amplitude and altitude. Keywords: Mesoscale convective system, lightning activity, lightning detectio
Michaela Geiger, Christl M. Maier, Uta Schmidt (éd.), Essen und Trinken in der Bibel. Ein literarisches Festmahl für Rainer Kessler zum 65. Geburtstag, Gütersloh, Gütersloher Verlagshaus, 2009
No full textHunziker-Rodewald Regine. Michaela Geiger, Christl M. Maier, Uta Schmidt (éd.), Essen und Trinken in der Bibel. Ein literarisches Festmahl für Rainer Kessler zum 65. Geburtstag, Gütersloh, Gütersloher Verlagshaus, 2009. In: Revue d'histoire et de philosophie religieuses, 90e année n°3, Juillet-Septembre 2010. pp. 383-384
Schmidts Samstag LIVE in der Unibibliothek
No full textMitschnitt der SWR1-LIVE-Sendung "Schmidts Samstag", moderiert von Thomas Schmidt. Interview der Reporterin Michaela Dymski mit Studierenden der Universität Heidelberg und mit Lesesaalleiter der Universitätsbibliothek Dr. Martin Nisse
Database Temperate Deciduous and Coniferous Forests of the Solling Hills
No full textThe Database Temperate Deciduous and Coniferous Forests of the Solling Hills (GIVD ID EU-DE-017) offers forest vegetation relevés obtained from different research projects during four decades in the Solling Hills (Lower Saxony, Germany). It contains relevés mainly of pure beech stands (Fagus sylvatica, Luzulo-Fagetum) representing the potential natural vegetation on acidic soils of the Solling Hills. Many parts of the Solling Hills have been converted into spruce monoculture stands (Picea abies, which is not native to the region) during the last few centuries. Meanwhile a conversion of pure spruce stands into mixed stands dominated by beech is one of the main goals of silviculture in Germany. The relevés from pure beech and spruce stands as well as mixed beechspruce stands offer good opportunities e.g. to compare composition and diversity of ground layer vegetation in relation to tree species composition or to evaluate the influence of different forest management activities to species diversity. Furthermore repeated relevés on permanent plots enable an evaluation of the data regarding the impact of eutrophication (including liming) and climate change on forest ecosystems
Vegetation Database of Temperate Deciduous Forests of the Göttinger Wald
No full textThe Vegetation Database of Temperate Deciduous Forests of the Göttinger Wald (GIVD ID EU-DE-018) offers forest vegetation relevés obtained from various research projects between 1955-2011 in the Göttinger Wald (S-Lower Saxony, Germany). Single surveys as well as repeated surveys are included. Beech forests ecosystems on limestone with variable fractions of other broadleaved trees (e.g. Acer pseudoplatanus, Fraxinus excelsior) are characteristic. The database comprises classical phytosociological data, experimental ecological data and additional data for population-biological analysis
Vegetation Database of Strict Forest Reserves in NW-Germany
No full textStrict forest reserves are forests without any direct anthropogenic influence such as management activities. They have been established all over Germany as well as in many other European countries to gain a substantial, representative network of protected areas. Strict forest reserves can be used as a reference for forestry and nature conservation in order to derive modern forestry practices including the main goals of sustainability and biodiversity. Besides this they offer valuable opportunities for fundamental research on forest biocoenoses. Our database comprises woodland relevés from 17 strict forest reserves (permanent plots) in Lower Saxony and Hesse (Germany). Beside single surveys, mainly repeated surveys have been conducted (time series).The database offers good opportunities to evaluate changes in time (forest dynamics, succession), impact of management activities or environmental changes on forest ecosystems. This report describes the available content in the Vegetation Database of Strict Forest Reserves in NW-Germany (GIVD ID EU-DE-016)
Vegetation Database of Successional Permanent Plots in Göttingen
No full textSince 1968 an experimental study site on old-field succession in Göttingen (Lower Saxony, Germany) has delivered continuous data on vegetation development on permanent plots. The 23 plots (125–200 m²) cover a range of undisturbed sites since the beginning of the experiment or since 1983 differing in their initial treatment, to plots undergoing a certain yearly treatment like mowing intensities (with and without fertilizer treatment) or ploughing. Beside continuous species lists and cover values, soil chemical properties, biomass data, measurement of PAR or seed bank analysis are available whether continuous or as interval data. Such longterm permanent plot studies, in particular in comparison with similar case studies from all over the world, may enlarge our knowledge on patterns and processes of vegetation dynamics. This report describes the available content in the Vegetation Database of Successional Permanent Plots in Göttingen (GIVD ID EU-DE-015)
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