Lichen Heath Research Articles

Morphological analysis of alpine communities of the north-western Caucasus

The species composition of four alpine communities in the north-western Caucasus was subjected to a morphological analysis. The communities are an alpine lichen heath type (ALH), aFestuca varia grassland type (FVG), aGeranium-Hedysarum meadow type (GHM) and a snowbed community (SBC). Eighty-two species were studied, using the following morphological parameters: vegetative mobility, presence of rosettes, architectural model, life form according toRaunkiaer and life form according toSerebryakov. Representation spectra were calculated on the basis of species presence, above-ground phytomass proportion and species frequency. The results show that most alpine species have a low vegetative mobility; a semi-rosette growth form; a sympodial semi-rosette model of shoot formation and that they are characterised by the prevalence of hemicryptophytes. Differences between the four communities were found in the following features: tap-rooted and short-rhizome plants dominate in ALH and, moreover, dense-tussock plants are dominant in the phytomass; short-rhizome (species presence) and dense- tussock plants (phytomass) are dominant in FVG; short-rhizome and loose-tussock plants dominant in GHM; semi-shrub (phytomass basis) and loose-tussock plants are dominant of SBC. Tuberiferous, bulbiferous and monocarpic plants are not important in any of the communities. *** DIRECT SUPPORT *** A02DO006 00008

Comparative analysis of the floristic richness of alpine communities in the Caucasus and the Central Alps

Abstract. Species richness of selected alpine plant communities in the Teberda Biosphere Reserve (Northwestern Caucasus) and the Davos area (Central Alps) was compared in series of plots from 0.0025 to 100 m2. Communities developing under similar ecological conditions and with similar syntaxonomic positions were compared in order to estimate the role of recent environment versus regional historical factors in determining plant community structure and diversity. The floristic richness of the Caucasian and Alpic fens was very similar. The Grasslands and Meadows were quite similar as to floristic richness for plots > 25 cm × 25 cm, but the Caucasian communities had fewer species in smaller plots. The Lichen heath at Teberda was richer than the Caricetum curvulae cetrarietosum for all plot sizes, except the two smallest ones. On the other hand, the plots of the Salix Snowbed community were richer in species than the Caucasian snowbeds for all plot sizes. The Rhododendron Shrubland plots were very similar as to floristic richness in larger plots (4 — 100 m2). Generally, most Alpic communities near Davos were richer in species at small plot sizes than the corresponding communities from Teberda. Caucasian communities were floristically less similar to each other — and thus more discrete — than the Alpic ones.The possible role of different factors controlling floristic richness of the communities is discussed. Our results suggest that recent ecological conditions have a big influence on local floristic diversity and may lead to high similarities between ecologically similar communities from different regions. In addition, the general floristic richness of a regions as well as island effects should be taken into account.

Analysis of surface structures ofCladonia mitispodetia in historic and recent collections from Greenland

Field observations in Greenland combined with a scanning electron microscopical survey have revealed a hitherto undescribed correspondence in the distribution of a brownish colour and a crust-like surface structure formed by hyphae at exposed parts of the shoot tips of podetia of Cladonia mitis. A different brownish colour pattern is caused by fungal parasites. A comparable but less prominent colour-crust syndrome was observed on C. mitis from Denmark. The colour-crust syndrome is considered an unhealthy and damaged condition, and the light microscope reveals that areas with this syndrome mainly consist of the uncovered stereome devoid of the hyphal zone containing algal colonies. In a comparative study of podetia collected up to 105 years ago in Greenland, crust-like surface structures occur more frequently since the 1970s. Key words: Arctic lichen heath, Cladonia mitis, Greenland, podetial morphology, UV-B radiation.

Species-specific plant responses to exclusion of grazers in three Fennoscandian tundra habitats

AbstractAn exclosure experiment performed in 1977-1985 in three tundra habitats was re-analyzed to examine species-specific plant responses for dominating species. In the lichen heath, four woody species showed the strongest increases as a response to the grazer exclosure. In the meadow, a tall grass showed the strongest increase in the exclosures, while a creeping woody plant increased in the snowbed exclosures. The species that increased in the exclosures were consistently those which were capable of elevating their foliage above the prevailing foliage height, while semiprostrate and prostrate plants (most notably bryophytes and lichens) suffered heavily from the exclusion of grazers.

Biodiversity in montane Britain: habitat variation, vegetation diversity and some objectives for conservation

The montane (low- to mid-alpine) zone in Great Britain (GB) lies above the potential tree-line (700–800 m, but descending to 200 m in the north). It is composed of moss and lichen heaths, snowbeds, blanket bog and dwarf-shrub (Ericaceae) health-covered solifluction/gelifluction terraces (38 communities/sub-communities). Approximately 3.0% of the land surface is covered by this- the most extensive predominantly near-natural terrestrial habitat in GB. Internationally distinctive features include oceanic and southern biotic outliers of arctic-alpine fellfield and mountain tundra, and plant communities that are either globally rare/localised or especially well represented in GB. The absence of extensive sub-alpineBetula spp. andSalix spp. scrub is striking.

Lichens at Dungeness

LAUNDON, J. R., 1989. Lichens at Dungeness. The lichen vegetation at Dungeness is reviewed. The most important lichen communities are of three types. Firstly, there are the crustose lichens which colonize the bare pebbles. Secondly, the tracts of rich Cladonia turf which form the lichen heath and which play a major role in the vegetation cycle. Thirdly, there are the epiphytes on Prunus scrub. In addition, lichens on artificial substrates, especially wooden fences, are noteworthy. About 150 species occur, amongst the most interesting being Cladonia mitis, Lecanora helicopis, Lecidea insidiosa, Parmelia soredians, Rinodina aspersa and Umea glabrata. A new combination is made in the genus Porpidia. The term ‘bird farming’ is published. The fragmentation of the vegetation by building and gravel extraction receives critical comment.

Distribution, activity, life‐history and standing crop of Julidae (Diplopoda, Myriapoda) in the Central High Alps (Tyrol, Austria)*

The research area includes subalpine meadows, alder communities, dwarf‐shrub heaths, lichen heaths and highalpine meadows (1960 m–3090 m a.s.l.). The material consists of 4419 Julidae (31.6% adult) collected by extraction of litter samples (66.4%), in pitfall traps (26.3%) and by handsampling (7.3%). Cylindroiulus meinerti (Verhoeff) only occurred below 2000 m; Leptoiulus saltuvagus (Verhoeff) was mainly found at Alnus viridis sites; Leptoiulus simplex (Verhoeff) had its main distribution in the lichen heath (2200‐2300 m); Ommatoiulus sabulosus (L.) was found most frequently in the subalpine meadow and Leptoiulus alemannicus (Verhoeff) occurred up to 2800 m without any altitudinal concentration.Adults of L. saltuvagus showed only one distinct activity peak in September, those of L. simplex were diplochronous (June/September) and O. sabulosus summer stenochronous (July). L. saltuvagus reached maturity in stage IX (only males), X or XI after four or five Years. In their first year of growth the members of a generation reached the third or fourth stage, in the second year the sixth or seventh, in the third year the eighth or ninth. Females could carry full‐sized eggs in the autumn of the fourth year in the tenth stage or in the fifth year in stage eleven. Apparently eggs may be laid in spring of the fifth or sixth year. Overwintering density of L saltuvagus in alder litter was found to be 215.6 ± 38.7 inds m−2, the mean biomass 1.16 g m−2(max. 1.88 g m−2). Mean annual production during the growth period of 4‐5 months was in the order of 0.85 g m−2 (max. 1.36 g m−2).

Adaptations in Xenylla maritima and Anurophorus laricis (Collembola) to Lichen Habitats on Alpine Rocks

Adaptations to climatic extremes were studied in two collembolan species, Xenylla maritima and Anurophorus laricis, inhabiting lichens on alpine rocks 1200 to 1250 m a.s.l. at Finse, South Norway. Both species show seasonal variation in cold hardiness. Gut evacuation and accumulation of cryoprotective substances during autumn result in an ability to supercool to temperatures below normal winter temperatures. An exceptionally cold period in January 1979, however, killed most animals on unprotected sites of the rocks. The great ability of the two species to tolerate anaerobic conditions, is important to survive periods in winter when the rock surface is enclosed by an ice crust. Adaptation to dry conditions was evident from the great ability of both species to survive drought stress. They also reproduce later in the season than most other collembolan species thus reducing the risk for the sensitive hatchlings to emerge during the driest periods of summer. In all these aspects X. maritima and A. laricis differ greatly from Collembola of climatically protected habitats. Tetracanthella wahigreni inhabiting the surrounding lichen heath, is also highly adapted to cold and anaerobic conditions, but is more susceptible to desiccation than the two rock species. The comparison with T. wahlgreni emphasizes humidity as an important factor structuring the spatial distribution of collembolan species.

Soil Ecology of a Lichen Heath at Spitsbergen, Svalbard: Effects of Artificial Removal of the Lichen Plant Cover

Also included is an erratum for the article “Seasonal Vegetative Establishment and Shoot Reserves of Eastern Gamagrass.”

The Modern and Late Quaternary Vegetation of the Campbell‐Dolomite Uplands, near Inuvik, N.W.T., Canada

The Campbell—Dolomite uplands comprise a small area (140 km2) of outcropping, faulted dolomite, limestone, and shale east of the Mackenzie River Delta, ~ 40 km south of the northern limit of trees. The major landforms are bedrock ridges and plateaux, steep colluvium, stable slopes, shorelines, and depressions. A principal component analysis of vegetation—cover data from 150 stands suggest that much of the variation within the heterogeneous vegetation is correlated with these broad habitat categories. Stable surfaces bear an open spruce woodland with alder, tree and dwarf birch, and a varied lichen—heath—Dryas ground vegetation. A glacially modified karstic (solution) depression contains a small (8 ha), relatively deep (22 m), apparently meromictic lake, which yielded a 12,000—yr core of sediment. A conventional percentage diagram, an influx diagram, and numerical analysis (principal components) suggest a sequence of pollen assemblage zones as follows: (1) Salix—Gramineae—Artemisia: 13,000 to 11,300 radiocarbon yr ago, (2) Betula (shrub)—Salix—Gramineae—Artemisia: 11,300 to 10,300, (3) Betula—Populus: 10,300 to 9,700, (4) Betula—Populus—Juniperus: 9,700 to 8,900, (5) Picea—Betula (tree and shrub)—Juniperus: 8,900 to 6,500, and (6) Picea—Betula—Alnus: 6,500 to present. Both percentage data and numerical analyses show that none of the pollen assemblage zones 1 to 5 has a modern analogue. With 1 exception, these patterns of change in pollen spectra can be interpreted parsimoniously without reference to regional environmental change. They suggest an initial phase of migration of willow and herbs from adjacent unglaciated Megaberingia (North Yukon and Alaska), followed rapidly by dwarf birch and later poplar. Megaberingian floristic elements (e.g., Plantago canescens, Selaginella sibirica) reached the area during this early phase of migration. Subsequently arriving from the south along the Mackenzie valley were juniper, ericads, spruce, and finally alder, which intensified competition and restricted the early Megaberingian herb types to open, unstable habitats where they persist today. Slow soil development (humus accumulation, rising permafrost table) probably favoured the spread of the palynologically 'silent' elements–lichens, ericads, and Dryas (the dominants of the modern ground vegetation). Changes in the influx values of Picea suggest a climatically induced increase in tree density and/or pollen production during the period 9,000—7,000 BP (Zone 5).

Anaerobiosis in Overwintering Collembolans and Oribatid Mites from Windswept Mountain Ridges

Parts of windswept mountain ridges, covered with lichen heath, often remain snow-free during the winter. Due to freezing of their surroundings, collembolans and mites from the soil of this habitat are probably exposed to periods of oxygen deficiency during the winter. In the laboratory two species of oribatid mites from this habitat, Calyptozetes sarekensis (Trag.) and Carabodes labyrinthicus (Mich.) survived several weeks of anoxia at 0?C, some specimens for more than 96 d. Specimens of the collembolan Tetracanthella wahlgreni Linnaniemi survived similar periods, while Isotoma violacea Tullgren was killed within 6 to 8 d of anoxia. Survival of C. labyrinthicus was similar in specimens collected during the summer and winter, while T. wahigreni survived longer periods of anoxia during the winter. During anaerobiosis lactate was accumulated in C. labyrinthicus and T. wahigreni. It was also formed in I. violacea, which suggests that the formation of lactate in itself is not the only adaptation to survival under oxygen deficiency.

Studies on lichen-dominated systems. XVII. The colonization of young raised beaches in NW Ontario

The colonization of young raised-beach ridges and the subsequent development of lichen–heath vegetation is described for the Hudson Bay coastal tundra. The sequence of development of lichen–heath was quantified both on a coastal intraridge sequence as well as an interridge, inland sequence of comparable age. Corresponding gradients of elevation, soil peat thickness and organic matter were found along the developmental sequence, but definite trends in soil pH and available nutrients are absent. Superimposed upon the distributions of major species along the developmental sequence are marked changes in abundance over the beach-ridge profiles which reflect the adaptations of species to environmental factors related to ridge microtopography.

THE HILL VEGETATION OF NORTH HOY, ORKNEY

SUMMARYNorth Hoy is an area containing a remarkable diversity of vegetation in a small area. A phytosociological account of the hill vegetation of North Hoy is presented, making use of an ordination method to clarify the inter‐relationships of the moorland vegetation types, as well as traditional methods. It has proved very interesting to compare the vegetation with the account of Scottish Highland vegetation by McVean and Ratcliffe (1962). Birks' (1973) account of the vegetation of Skye has also been drawn on, particularly as a source for a system of classes, orders and alliances applicable to Scottish vegetation. The environmental background (climate, topography, geology, patterned ground phenomena, animal populations and past and present land‐use) is summarized.Several important general features of the vegetation of North Hoy deserve emphasis, especially from a conservation point of view. Many good examples of noda characteristic of strongly basic soils, especially mires and grasslands, are found. Some of these have a rather restricted distribution in Scotland. Small areas of woodland, including one very species‐rich wood, are found in sheltered ravines. These are well‐developed and regenerating, and represent the northernmost occurrence of woodland in Britain. Many species and many types of vegetation occur at unusually low altitudes (as is also observed in northernmost Sutherland, Caithness and Shetland). Particularly interesting are certain montane dwarf heaths, which are associated with well‐developed patterned ground features. The area contains both occurrences of ‘Atlantic’ bryophytes and well–developed stands of lichen heath and lichen‐rich bog, which have a strongly ‘continental’ distribution in Scotland. This apparent paradox is discussed but not resolved. The low level of sheep‐grazing and absence of burning in recent years have led to some unusual vegetation features. Phytosociological tables are presented in an appendix. A second appendix lists the lichens collected, as identified by P. W. James, with a short note on the occurrence of each.

Studies on lichen-dominated systems. XI. Lichen–heath and winter snow cover

Several tundra beach ridges, adjacent sedge meadows, and forested areas some distance inland were examined in midwinter, late winter, and early spring to assess the potential importance of variations in snow cover to the underlying vegetation.Tops of beach ridges were found to be nearly snow-free all winter and were fully exposed early in the spring. Sedge meadows and forested areas had a thicker cover.The vegetational characteristics of each area appear adapted to the winter snow conditions.

Studies on lichen-dominated systems. VII. Interaction of the general lichen–heath with edaphic factors

The patterns of variation in vegetation and the more apparent environmental parameters within and between the ridges of a recently formed Hudson Bay coastal raised-beach system 1.5 km wide are presented and analyzed using principle-component analysis and correlation coefficients. Previous research in the area did not detect such patterns within the general lichen–heath.There is a marked developmental sequence from the coast inland, involving increases in the soil moisture content and the peat-layer thickness, but variations independent of any age sequence occur on an intraridge basis. Relationships are drawn between these variations and the biomass or cover of nine important species.

Vegetation Pattern in a Moss: Lichen Heath Associated with Primary Topographic Features on Jan Mayen

The distribution of cryptogams across a ridge-hollow system was assessed by estimating percentage cover along a transect of contiguous quadrats and correlated with exposure to the prevailing northerly wind, winter snow lie, aspect, and inclination. Stereocaulon species are the most tolerant of wind ex- posure, followed by Rhacomitrium lanuginosum. Rhacomitrium canescens and Cladonia mitis are both associated with late snow lie, the latter species being lim- ited to the most favorable habitats in respect to aspect and inclination. The vegetation of Jan Mayen Island (7100'N, 8030'W) has been described in out- line by Russell and Wellington (1940). The porous nature of the basaltic rocks, the thin and immature soils together with the rigors of the subarctic climate limit the development communities dominated by higher plants to small areas with a particularly favorable environment. The greater portion of the vegetation of the island consists of a moss mat dominated Rhacomitrium lanuginosum (Hedw.) Brid. and R. canescens (Hedw.) Brid. (Wilson, 1952), but little attention has been paid to the ecology of these communities. of a series of ridges with amplitudes of 1-6 feet (0.3-1.8 meters) and orientated in different parts of the lava field towards diverse points of the compass. These ridges are primary topographic features formed by surface cooling of the molten lava flows. The flows belong to the last major eruption cycle of the volcano Beerenberg, the Koksletta Formation (Fitch, 1964), and have been dated at 2,500-3,500 years old. The lava platform is open to the sea on the north, west, and south sides but sheltered immedi- ately to the east by fossil sea cliffs of the older Tromsoryggen Formation and to the

Vegetation Pattern in a Moss: Lichen Heath Associated with Primary Topographic Features on Jan Mayen

Vegetation Pattern in a Moss: Lichen Heath Associated with Primary Topographic Features on Jan Mayen