1,721,058 research outputs found

    Grassland restoration at a graded ski slope: Effects of propagation material and fertilisation on plant cover and vegetation

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    The increasing anthropisation of mountain regions is a cause of soil degradation, which needs to be addressed. Conventional methods of ski slope revegetation often fail to stabilise the soil and recover natural vegetation. To test alternative methods to create a persistent, biodiversityfriendly plant cover, different sowing (site-adapted native propagation materials vs. forage cultivars vs. no sowing) and fertilisation treatments were compared over nine years at a graded ski slope. Because of the gravelly soil, the ninth-year plant cover was only 65%, which was sufficient to prevent erosion. All native propagation materials were equally efficient at recreating a semi-natural grassland. Except for Festuca rubra, the forage cultivars did not persist. However, native volunteer species from close natural ecosystems efficiently colonised plots sown with forage cultivars and plots that were not sown. This resulted in a lower plant cover but a high similarity to the surrounding vegetation. Fertilisation had a positive but transient effect on plant cover and a little negative effect on species richness. High-altitude sites with gravelly soils should be revegetated with native propagation materials. Using forage cultivars can attain a persistent plant cover only if the sown non-persistent cultivars are replaced by the species arriving from nearby surrounding vegetation

    Anti-erosion rehabilitation: Effects of revegetation method and site traits on introduced and native plant cover and richness

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    In mountainous areas, bare slopes represent often dangerous forms of land degradation that need to be rehabilitated. However, revegetation is usually performed with non-native plants, negatively impacting the natural landscape value. Comprehensive studies, especially on poorly investigated long-term revegetation effects, are therefore essential for the improvement of rehabilitation practices. In this study, four landslides or disused quarries surrounded by well-preserved (semi-) natural vegetation that were revegetated between 1988 and 2002 with non-native only herbaceous or both herbaceous and woody plants were studied 1–9 and 16–31 years after rehabilitation. A total of 111 sampling areas were surveyed for introduced and volunteer species and other important ground cover soil and topography traits. Climatic traits and species' ecological indicators were retrieved from the available databases. The time patterns and ecological spectra of the plant covers were analysed and correlated to the site traits. In the first decade, introduced plants were initially abundant but decreased rapidly. In the long-term, the more stress-tolerant among them still had a considerable cover, especially in fine-textured soils. Native species were established slowly but, due to their higher stress tolerance, dominated in the long-term, especially at more stressful sites. In areas with predominantly herbaceous cover, soil factors, such as gravel content, were more related to the plant cover. In areas with predominantly woody plant cover, the high plant cover was dependent on microclimatic factors, especially aspect. At sites like those studied here, woody species should be always used, but in the form of native plants, as they tend to persist. If herbaceous species are unavailable in native forms, their introduction should be avoided in areas not exposed to erosion, whereas poorly stress-tolerant non-native plants should be used in steep areas as they create a fast but short-lasting cover compensated in the long term by the establishment of native species

    Effects of fertilisation on grass and forb gamic reproduction in semi-natural grasslands

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    Studying the effects of fertilisation on the seed production of grassland species can help understand the vegetation changes and biodiversity losses due to soil eutrophication. The seed production of fifteen grasses and seventeen forbs from a temperate hay meadow was studied under three fertilisation treatments: 0-0-0, 0-54-108 and 192-108-216 kg N, P2O5 and K2O respectively, per year. Fertile shoots collected at the seed maturation stage were analysed for all main traits of the gamic reproduction. On average, forbs produced more ovules and viable seeds per shoot (199 and 65, respectively) than grasses (112 and 35, respectively). Fertilisation increased the number of inflorescences per shoot in both grasses and forbs and had a limited but variable effect on germinability and viability in the two functional groups: viability increased in grasses but often decreased in forbs. This pattern resulted in 55% and 11% increases in viable seed production in grasses and forbs, respectively. At the higher level of fertilisation, shoot density was positively related to the number of viable seeds per shoot in grasses and to the seed size in forbs. These results highlight that the traits of the gamic reproduction can contribute to explain the relationship between soil nutrient richness and grassland species composition and richness

    Efficiency and allometry of seed production in grassland forbs: Site and year comparative study in the Italian Eastern Pre-Alps

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    Forbs are important biodiversity components of grasslands and are often threatened by management intensification. As most forbs propagate predominantly by seed, knowledge of their seed regenerative traits would improve the conservation and restoration of forb-rich ecosystems. The main seed production traits of six forbs that are common in European species-rich grasslands were studied by collecting fertile shoots from different sites and over several years. Among sites and years, variability was high, particularly in the number of inflorescences per shoot, which affected ovule production more than any other trait. Relationships between inflorescence size and the number of ovules were mainly negatively allometric or almost so, with lower flower densities in larger inflorescences. The average ovule-to-seed transformation efficiency was 58%. There was significant variation among collections of the same species, and even more between species. Species with a low ovule-to-seed transformation efficiency generally exhibited compensatory, high seed viability. Large inflorescences had high ovule to seed utilization values, probably because of better nutrient conditions. Seed germinability (average, 30%) was much lower than seed viability (average, 54%); therefore, seed dormancy was an important feature of the species studied

    Progettare un magazzino con il metodo della "alloccazione correlata"

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    Nel presente articolo gli autori presentano l’applicazione della metodologia dell’allocazione correlata ad una realtà manifatturiera dimensionando il magazzino destinato ad accogliere gli articoli provenienti dai fornitori ed effettuando la disposizione dei prodotti in scaffalature che consentono di migliorarne l’utilizzazione volumetrica. I risultati conseguiti rappresenta indubbiamente un’innovazione rispetto ai sistemi tradizionali di collocazione dei prodotti nei vani del magazzino ottenendo dei buoni risultati di utilizzabilità degli spazi a disposizione e di una contrazione dell’area destinata a magazzin
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