@article{ZibulskiHerzschuhPestryakova2016,
  author    = {Zibulski, Romy and Herzschuh, Ulrike and Pestryakova, Luidmila Agafyevna},
  title     = {Vegetation patterns along micro-relief and vegetation type transects in polygonal landscapes of the Siberian Arctic},
  series = {Journal of vegetation science},
  volume    = {27},
  journal   = {Journal of vegetation science},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {1100-9233},
  doi       = {10.1111/jvs.12356},
  pages     = {377 -- 386},
  year      = {2016},
  abstract  = {QuestionHow important is the effect of micro-relief and vegetation type on the characteristics of vascular plants and bryophytes in low-centred polygons? LocationSiberian Arctic, Russia. MethodsEight low-centred polygons in northern Siberia were surveyed for vegetation along transects running from the rim to the pond via the rim-pond transition of each polygon and across a vegetation type gradient from open forest to tundra. ResultsThe cover of vascular plants and bryophytes displays no significant differences between the rim and rim-pond transition but is significantly lower in the pond section of the polygons. Alpha-diversity of vascular plants decreases strongly from rim to pond, whereas bryophyte diversity in pond plots is significantly distinct from the rim and the rim-pond transition. There is no clear trend in cover for either plant group along the vegetation type transect and only a weak trend in -diversity. However, both gradients are reflected in the compositional turnover. The applied indicator species analysis identified taxa characteristic of certain environmental conditions. Among others, we found vascular plants primarily characteristic of the rim and bryophyte taxa characteristic of each micro-relief level and vegetation type. ConclusionsThe observed gradual pattern in -diversity and composition of polygonal vegetation suggests that micro-relief is the main driver of changes in the vegetation composition, while vegetation type and the related forest cover change are of subordinate importance for polygonal vegetation patterns along the Siberian tree line.},
  language  = {en}
}
@article{TabaresMapaniBlaumetal.2018,
  author    = {Tabares, Ximena and Mapani, Benjamin and Blaum, Niels and Herzschuh, Ulrike},
  title     = {Composition and diversity of vegetation and pollen spectra along gradients of grazing intensity and precipitation in southern Africa},
  series = {Review of palaeobotany and palynology : an international journal},
  volume    = {253},
  journal   = {Review of palaeobotany and palynology : an international journal},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0034-6667},
  doi       = {10.1016/j.revpalbo.2018.04.004},
  pages     = {88 -- 100},
  year      = {2018},
  abstract  = {Understanding vegetation-modern pollen relationships is essential to provide confidence in fossil pollen reconstructions of long-term vegetation changes in savanna ecosystems. In this paper we compare the taxonomical composition and the diversity (Hill NO, N1, N2) of vegetation and modern pollen along precipitation and local grazing-intensity gradients in Namibian savannas. Modern pollen was extracted from surface soil samples collected from 5 x 5 m plots distributed along four 500 m gradients. Vegetation was surveyed in each plot. The results show a high correspondence between vegetation and pollen data in terms of composition. Precipitation and grazing explain a significant although low proportion of compositional change in the vegetation and pollen spectra. We identified pollen taxa as indicators of grazing pressure such as Limeum, Alternanthera, and particularly Tribulus. Correspondence between vegetation and pollen data in terms of taxa richness (NO) is limited, probably because of the influence of landscape heterogeneity and openness, as well as low pollen concentrations. In contrast, the effective numbers of common and dominant taxa (N1, N2) are consistent among the different datasets. We conclude that in spite of limitations, modern pollen assemblages can reflect changes in vegetation composition, richness and diversity patterns along precipitation and grazing gradients in savanna environments. (C) 2018 Elsevier B.V. All rights reserved.},
  language  = {en}
}