Mean cover and frequencies of vascular plant species during three decades around Abisko Scientific Research Station

Plant species distributions are expected to shift and diversity is expected to decline as a result of global climate change, particularly in the Arctic where climate warming is amplified. We have recorded the changes in richness and abundance of vascular plants at Abisko, sub-Arctic Sweden, by re-sampling five studies consisting of seven datasets; one in the mountain birch forest and six at open sites. The oldest study was initiated in 1977-1979 and the latest in 1992. Total species number increased at all sites except for the birch forest site where richness decreased. We found no general pattern in how composition of vascular plants has changed over time. Three species, Calamagrostis lapponica, Carex vaginata and Salix reticulata, showed an overall increase in cover/frequency, while two Equisetum taxa decreased. Instead, we showed that the magnitude and direction of changes in species richness and composition differ among sites.

AMS radiocarbon dates and pollen analysis from Zugspitzplatt

On the strongly karstified and almost unvegetated surface of the Zugspitzplatt, at an altitude of about 2290 m in the Wettersteingebirge, there is a doline within which over a period of several thousand years a bed of fine loess-like sediment, almost 1m thick, has accumulated. Notwithstanding the situation of this locality far above the present tree-line, this infill contains quantities of pollen and spores sufficient for pollen analysis without use of any enrichment techniques. Despite poor pollen preservation, it was possible to date the basal layers of this profile on the basis of their pollen assemblages. AMS dating (7415 ± 30 BP) has confirmed that the oldest sediments were laid down during the early Atlantic period, the time of the thermal optimum of the Holocene. At least since that time this site has never been overridden by a glacier. The moraine associated with the Löbben Oscillation between 3400 and 3100 BP - here represented by the so-called Platt Stillstand (Plattstand) - did not quite reach the doline. A diagram shows known Holocene glacial limits. The composition of the pollen assemblages from the two oldest levels with high pollen concentrations strongly suggests that the distance between the doline and the forest was much less during the Atlantic than at present.

Pollen record and age determination of sediment core Fersina 2

Pollen analysis of samples taken from the core of the water well Fersina 2 (Adige Valley, Prov. Trento, NE Italy) did not reveal any indication of an interglacial or Holocene age of the uppermost 190 m in the sediment sequence deposited in the over-deepened Adige River Valley. The sediment sequence dates entirely from late-glacial times. Four radiocarbon ages of pieces of wood indicate that about 165 m of the upper part of the profile are of Younger Dryas age. The lower part of the sequence dates from the Allerød or Bølling/Allerød and a preceding cold phase, probably the Oldest Dryas. Accordingly the deposition of the sequence took about 2500 or 3500 years and was completed long before the onset of the Neolithic. Our results are in excellent agreement with findings in other formerly glaciated alpine valleys (e.g. the Traun, Salzach and Enns valleys in the Northern Alps). The final depth of the Fersina 2 well is 190 m. It is very likely that the sediment sequence found below this level in the nearby 423 m deep Fersina 1 well was also deposited after the deglaciation of the Adige Valley at the end of the last glacial period.

Vegetation, soil and site characteristics of samples taken along the Yamal Transet in 2007-2008

The overarching goal of the Yamal portion of the Greening of the Arctic project is to examine how the terrain and anthropogenic factors of reindeer herding and resource development combined with the climate variations on the Yamal Peninsula affect the spatial and temporal patterns of vegetation change and how these changes are in turn affecting traditional herding of the indigenous people of the region. The purpose of the expeditions was to collect groundobservations in support of remote sensing studies at four locations along a transect that traverses all the major bioclimate subzones of the Yamal Peninsula. This data report is a summary of information collected during the 2007 and 2008 expeditions. It includes all the information from the 2008 data report (Walker et al. 2008) plus new information collected at Kharasavey in Aug 2008. The locations included in this report are Nadym (northern taiga subzone), Laborovaya (southern tundra = subzone E of the Circumpolar Arctic Vegetation Map (CAVM), Vaskiny Dachi (southern typical tundra = subzone D), and Kharasavey (northern typical tundra = subzone C). Another expedition is planned for summer 2009 to the northernmost site at Belyy Ostrov (Arctic tundra = subzone B). Data are reported from 10 study sites - 2 at Nadym, 2 at Laborovaya, and 3 at Vaskiny Dachi and 3 at Kharasavey. The sites are representative of the zonal soils and vegetation, but also include variation related to substrate (clayey vs. sandy soils). Most of the information was collected along 5 transects at each sample site, 5 permanent vegetation study plots, and 1-2 soil pits at each site. The expedition also established soil and permafrost monitoring sites at each location. This data report includes: (1) background for the project, (2) general descriptions and photographs of each locality and sample site, (3) maps of the sites, study plots, and transects at each location, (4) summary of sampling methods used, (5) tabular summaries of the vegetation data (species lists, estimates of cover abundance for each species within vegetation plots, measured percent ground cover of species along transects, site factors for each study plot), (6) summaries of the Normalized Difference Vegetation Index (NDVI) and leaf area index (LAI) along each transect, (7) soil descriptions and photos of the soil pits at each study site, (8) summaries of thaw measurements along each transect, and (9) contact information for each of the participants. One of the primary objectives was to provide the Russian partners with full documentation of the methods so that Russian observers in future years could repeat the observations independently.