F. J. A. Daniels

Species responses to experimentally induced habitat changes in a Corynephorus grassland

Abstract Question: To which extent do external ecological factors effect Corynephorus grassland vegetation? Location: Central Netherlands. Methods: We implemented different treatments (sand deposition, litter deposition, nitrogen input, mechanical disturbance, control) in permanent plots representing different successional phases in Corynephorus grassland. Plots were recorded just before the treatments and during the subsequent two years. Vegetation changes were analysed by Redundancy Analysis for repeated measurements and Correspondence Analysis, changes in single species abundances by ANOVA. Results: Species composition hardly changed during the observation period. Several single species abundances showed significant responses to different treatments, most often decrements as direct effects of cover, removal, or dieback. However, Corynephorus canescens and Polytrichum piliferum benefited from sand deposition, the exotic moss Campylopus introflexus from litter deposition. In the colonization phase Polytrichum, Campylopus and Cladonia diversa increased irrespective treatment. Therophytes such as Spergula morisonii showed the strongest negative response to drought, grasses (e.g. Corynephorus canescens) and bryophytes (e.g. Polytrichum piliferum) were less susceptible. Most lichens did not respond at all. Conclusions: The experiment confirms the high stability of Corynephorus grassland vegetation. Most vegetation changes are in accordance with the hypothetical series of successional phases. In contrast, changes in abundance of single species express considerable dynamics within the vegetation. Species responses also depend on extreme weather conditions as well as on the successional phase of the grassland vegetation and therefore on the competition situation. Abbreviations: CA = Correspondence Analysis; RDA = Redundancy Analysis. Nomenclature: Wisskirchen & Haeupler (1998) for vascular plants; Koperski et al. (2000) for bryophytes; van Herk & Aptroot (2004) for lichens; Ettl & Gärtner (1995) for algae.

Vegetation classification in Greenland

. An account of the description and classification of the vegetation of Greenland is presented. Four periods are recognized: the Physiognomic period, the Extension period, the Floristics-Dominance period, and the Syntaxonomic period. The approaches used in vegetation classification pertaining to Greenland are discussed. A first survey is presented of the higher syntaxa known from suboceanic-oceanic, subarcticlow arctic Greenland. 14 classes are dealt with. The syntaxa are floristically defined and their concept is discussed. The Juncetalia trifidi, Caricetea curvulae, are described for the first time.

Short-term accumulation of organic matter and nutrient contents in two dry sand ecosystems

Inland dunes in northwestern Europe support a number of dry vegetation types. These ecosystems are poor in nutrients and it has been suggested that accumulation of nutrients triggers succession in such systems. We studied the accumulation of organic matter and N and P over a 30 months period in two adjacent ecosystems, the Spergulo-Corynephoretum and the Genisto-Callunetum. Amounts of plant matter and soil organic matter significantly accumulated during the sampling period in the Genisto-Callunetum but not in the Spergulo-Corynephoretum. While nutrient concentrations of live and dead phytomass in the Spergulo-Corynephoretum were significantly higher than in the Genisto-Callunetum, total nutrient contents in the systems showed the opposite pattern. N and P concentrations in litter were relatively high compared with the other fractions of plant matter and the amount of N significantly increased in both ecosystems during the sampling period. Soil moisture contents showed a seasonal pattern. It was highest in the top soil layer and higher in the Genisto-Callunetum than in the Spergulo-Corynephoretum. The estimated annual increase of total N in these two ecosystems was consistent with rates of atmospheric N deposition (wet fall + dry fall) measured in comparable Dutch sites.

Toward a new arctic vegetation map: a review of existing maps

Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA; Fax +1 303 492 6388; E-mailDONALD.WALKER@COLORADO.EDU; Botanical Museum, University of Copenhagen, Gothersgade 130, DK-1123, Copenhagen, Denmark; Fax +45 35 32 22 10; Institut fur Okologie der Pflamen, Westfalische-Wilhelms-Universitädt, Hindenburgplatz 55, D-48143 Miinster, Germany; Fax +49 251 838371; Icelandic Museum of Natural History, Hiemmur 3, P.O. Box 5320, IS-125 Reykjavik, Iceland; Fax +354 1 620815; institute of Biology and Geology, Troms^ University, N-9037 Troms0, Norway; Fax +47 77 645600; ^ORUT Group Ltd., N-9005 Troms0, Norway; Tel. +47 776 80150; ^Faculty of Geography, Moscow State University, Moscow 119899, Russia; Fax +7 095 932 8836; University of Alaska Museum, Fairbanks, AK 99775-6960, USA; Fax +1 907 474 5469; ^U.S. Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, AK 99503, USA; Fax +1 907 786 3635; ^Komarov Botanical Institute, 197376 Russia, St. Peterburg, ul. Prof. Popova 2; Fax +7 812 234 4512; ^Canadian Forest Service, Northern Forestry Centre, 5320 122 Street, Edmonton, Alberta, Canada T6H3S5; Fax +1 403 435 7359

Circumpolar Arctic vegetation: a hierarchic review and roadmap toward an internationally consistent approach to survey, archive and classify tundra plot data

Satellite-derived remote-sensing products are providing a modern circumpolar perspective of Arctic vegetation and its changes, but this new view is dependent on a long heritage of ground-based observations in the Arctic. Several products of the Conservation of Arctic Flora and Fauna are key to our current understanding. We review aspects of the PanArctic Flora, the Circumpolar Arctic Vegetation Map, the Arctic Biodiversity Assessment, and the Arctic Vegetation Archive (AVA) as they relate to efforts to describe and map the vegetation, plant biomass, and biodiversity of the Arctic at circumpolar, regional, landscape and plot scales. Cornerstones for all these tools are ground-based plant-species and plant-community surveys. The AVA is in progress and will store plot-based vegetation observations in a public-accessible database for vegetation classification, modeling, diversity studies, and other applications. We present the current status of the Alaska Arctic Vegetation Archive (AVA-AK), as a regional example for the panarctic archive, and with a roadmap for a coordinated international approach to survey, archive and classify Arctic vegetation. We note the need for more consistent standards of plot-based observations, and make several recommendations to improve the linkage between plot-based observations biodiversity studies and satellite-based observations of Arctic vegetation.

Lichens from Simeonof Wilderness, Shumagin Islands, Southwestern Alaska

Abstract One hundred eighty-eight taxa of lichens are reported from Simeonof Island in the Shumagin Islands of southwestern Alaska. Wide-ranging arctic-alpine and boreal species dominate the lichens; a coastal element is moderately represented, while amphi-Beringian species form a minor element. The lichen component of Empetrum nigrum dwarf shrub heath, the dominant vegetation type, was analyzed to identify the most frequently occurring lichens within this community.

Mountain vegetation of south-facing slopes in continental West Greenland

Based on 143 relevés, mountain vegetation on south-facing slopes in continental West Greenland is analysed according to the Braun-Blanquet approach. Plant communities, their characteristic habitat conditions as well as their microtopographical and altitudinal distribution pattern are presented. This study completes a comprehensive regional survey of arctic vegetation and their altitudinal zonation in this part of Greenland (AZV Project). On south-facing slopes arctic steppe and associated vegetation types cover large areas and considerably enhance the biodiversity of the region. These thermoxerophytic vegetation types are assigned to the new class Saxifrago tr icuspidatae-Calamagrostietea purpurascentis that for the present encompasses the following syntaxa: Arabido holboel l i i-Caricetum spaniocarpae (including two newly described subassociations), Carici spaniocarpae-Sal icetum glaucae ass. nov., Saxifrago tr icuspidatae-Dryopteridetum fragrantis ass. nov., and an Arctostaphylos uva-ursi community. Habitats are characterized by a distinct continental climate with intense insolation and high evapotranspiration in summer. The circumneutral soils have a silty to sandy texture and low organic matter contents. The geographical distribution range of the Saxifrago-Calamagrostietea comprises the low-arctic continental parts of the North American continent ranging from the East Greenlandic to the North Alaskan fl oristic subprovince. Species and communities show clear differentiations along the altitudinal gradient e.g. in occurrence, abundance or distribution pattern and thus are used for identifying borderlines between altitudinal vegetation belts. On southfacing slopes, plant communities with limited altitudinal distribution range are particularly suitable for this purpose. Here, based on fl oristic and vegetation characteristics, four altitudinal vegetation belts (e-b) are distinguished with borderlines at 450, 850 and 1250 m a.s.l. Fundamental differences with regard to fl ora, vegetation and their altitudinal differentiation were found between southand north-facing slopes.

Floristic relationship between plant communities of corresponding habitats in southeast Greenland and alpine Scandinavia

Barkman’s similarity coefficients have been calculated for twelve ecologically related communities of southeast Greenland (SEG) and alpine Scandinavia (SCA). Comparisons were made between corresponding saxicolous lichen communities, dwarf shrub communities, snow bed communities and herb and Salix shrub communities. The corresponding SEG and SCA communities of extreme habitats have the same faithful taxa or the same dominant taxa, relatively few or no area-differential (ArD) taxa and they are floristically strongly related. They should be classified in one single association; the geographical variation is expressed in terms of geographical races. Corresponding vegetation types of mesic habitats have low floristic similarity coefficients, many ArD taxa and the same dominant taxa, or different faithful taxa. The geographical variation should be expressed here on the association level.

Vegetation of eastern Unalaska Island, Aleutian Islands, Alaska

Plant communities of Unalaska Island in the eastern Aleutian Islands of western Alaska, and their relationship to environmental variables, were studied using a combined Braun-Blanquet and multivari...

The Drabo corymbosae-Papaveretea dahliani − a new vegetation class of the High Arctic polar deserts

Abstract A new class and a new order (Drabo corymbosae-Papaveretea dahliani and Saxifrago oppositifoliae-Papaveretalia dahliani) have been described, and the Papaverion dahliani validated. This is vegetation of zonal habitats in lowlands of the High Arctic subzone A (or Arctic herb, cushion forb or polar desert subzone) and of ecologically equivalent sites at high altitudes on the mountain plateaus of the High Arctic. The new class spans three continents – North America (Canadian Arctic Archipelago and Greenland), Europe (parts of Svalbard and Franz Josef Land), and Asia, including northern regions of Chelyuskin Peninsula (Taymir Peninsula), Severnaya Zemlya Archipelago and De Longa Islands.