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Number of results: 5
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Abstract

The paper presents plant communities from northern Wedel Jarlsberg Land. 55 species of vascular plants were described in this region. Differentiation of plant communities is discussed as controlled by habitat conditions. Plant succession in intramorainal zones of Renardbreen and Scottbreen has been also considered.
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Abstract

The ability to grow clonally is generally considered important for plants in Arctic regions but analyses of clonal characteristics are lacking for entire plant communities. To fill this gap, we assessed the clonal growth of 78 plant species in the Petuniabukta region, central Spitsbergen (Svalbard), and analyzed the clonal and other life−history traits in the regional flora and plant communities with respect to environmental gradients. We distinguished five categories of clonal growth organs: perennial main roots produced by non− clonal plants, epigeogenous rhizomes, hypogeogenous rhizomes, bulbils, and stolons. Clonal growth differed among communities of the Petuniabukta region: non−clonal plants prevailed in open, early−successional communities, but clonal plants prevailed in wetlands. While the occurrence of plants with epigeogenous rhizomes was unrelated to stoniness or slope, the occurrence of plants with hypogeogenous rhizomes diminished with increasing stoniness of the substratum. Although the overall proportion of clonal plants in the flora of the Petuniabukta region was comparable to that of central Europe, the flora of the Petuniabukta region had fewer types of clonal growth organs, a slower rate of lateral spread, and a different proportion of the two types of rhizomes.
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Abstract

The rapidly changing Arctic provides excellent opportunities for investigating primary succession on freshly deglaciated areas. Research on the Gåsbreen foreland (S Spitsbergen) traced the succession of particular groups of organisms and species, particularly lichens and bryophytes, and determined the effect of selected abiotic factors on this succession. Fieldwork in 2008, employed a continuous linear transect of phytosociological relevés (1 m2) along the foreland. Data analysis allowed to distinguish five different succession stages and three types of colonisers. Canonical correspondence analysis and a permutation test showed that distance from the front of the glacier and fine grain material in the substrate mostly influenced the distribution and abundance of vegetation, and the steepness of the moraine hills affected the colonisation process, mainly in the older part of the marginal zone.
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Abstract

Vegetation was described in various spatial scales in the area of 37.8 km 2 including distinguishing vegetation units, vegetation mapping, recording phytosociological relevés (53), and completing species lists of vascular plants (86), mosses (124) and lichens (40). Phytosociological relevés were elaborated using ordination methods DCA and CCA. The relevés formed clusters corresponding well to a priori assigned vegetation units. Slope and stoniness significantly influenced the vegetation pattern. Despite the high latitude (nearly 80 ° N), the vegetation is rather rich in species. Non−native species do not expand. The moss Bryum dichotomum is reported for the first time from Svalbard archipelago.
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Abstract

Diurnal measurements of photosynthetic pr ocesses, effective quantum yield of photosystem II ( F PSII ), photosynthetic electron transport rate (ETR) were done in three domi− nant species of Arctic tundra ( Silene acaulis , Dryas octopetala , Salix polaris ) in Petunia− bukta, Spitsbergen. Daily courses of net photosynthesis (P N ) were calculated from chloro− phyll fluorescence data and daily photosynthesi s evaluated. The short−term field measure− ments were carried out in summer 2009, and 2010. Fluorometric parameters ( F PSII and ETR) were measured each 5 minutes as well as microc limate characteristics of the site for 10 (2009) and 8 days (2010), respectively. In all species photosynthetic ETR was well related to incident photosynthetically active radiation a nd leaf temperature. In general, D. octopetala exhibited slightly lower ETR than the other two speci es. Estimated maximu m photosynthetic rate (P Nmax ) reached 17.6, 21.4, and 22.9 μmol CO 2 m −2 s −1 for S. polaris , S. acaulis ,and D. octopetala , respectively. Daily photosynthesis reach ed comparable values in all species, D. otopetala , however, exhibited slightly lower values than the other two species both for overcast and fully sunny days (3.9 and 13.4 mmol CO 2 m −2 d −1 , respectively). The range of daily photosynthesis for S. polaris and S. acaulis studied, reached the ranges of 4.6–6.9 and 14.6–15.2 mmol CO 2 m −2 d −1 for overcast and fully sunny day, respectively.
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