Tomáš Peterka

Formalized classification of European fen vegetation at the alliance level

Phytosociological classification of fen vegetation (Scheuchzerio palustris-Caricetea fuscae class) differs among European countries. Here we propose a unified vegetation classification of European fens at the alliance level, provide unequivocal assignment rules for individual vegetation plots, identify diagnostic species of fen alliances, and map their distribution. 29 049 vegetation-plot records of fenswere selected fromdatabases using a list of specialist fen species. Formal definitions of alliances were created using the presence, absence and abundance of Cocktail-based species groups and indicator species. DCA visualized the similarities among the alliances in an ordination space. The ISOPAM classification algorithm was applied to regional subsets with homogeneous plot size to check whether the classification based on formal definitions matches the results of unsupervised classifications. The following alliances were defined: Caricion viridulo-trinervis (sub-halophytic Atlantic dune-slack fens), Caricion davallianae (temperate calcareous fens), Caricion atrofusco-saxatilis (arcto-alpine calcareous fens), Stygio-Caricion limosae (boreal topogenic brown-moss fens), Sphagno warnstorfii-Tomentypnion nitentis (Sphagnumbrown-moss rich fens), Saxifrago-Tomentypnion (continental to boreo-continental nitrogen-limited brown-moss rich fens), Narthecion scardici (alpine fens with Balkan endemics), Caricion stantis (arctic brown-moss rich fens), Anagallido tenellae-Juncion bulbosi (Ibero-Atlantic moderately rich fens), Drepanocladion exannulati (arcto-borealalpine non-calcareous fens), Caricion fuscae (temperate moderately rich fens), Sphagno-Caricion canescentis (poor fens) and Scheuchzerion palustris (dystrophic hollows). The main variation in the species composition of European fens reflected site chemistry (pH, mineral richness) and sorted the plots from calcareous and extremely rich fens, through rich andmoderately rich fens, to poor fens and dystrophic hollows.

Spring-fen habitat islands in a warming climate: Partitioning the effects of mesoclimate air and water temperature on aquatic and terrestrial biota

Climate warming and associated environmental changes lead to compositional shifts and local extinctions in various ecosystems. Species closely associated with rare island-like habitats such as groundwater-dependent spring fens can be severely threatened by these changes due to a limited possibility to disperse. It is, however, largely unknown to what extent mesoclimate affects species composition in spring fens, where microclimate is buffered by groundwater supply. We assembled an original landscape-scale dataset on species composition of the most waterlogged parts of isolated temperate spring fens in the Western Carpathian Mountains along with continuously measured water temperature and hydrological, hydrochemical, and climatic conditions. We explored a set of hypotheses about the effects of mesoclimate air and local spring-water temperature on compositional variation of aquatic (macroinvertebrates), semi-terrestrial (plants) and terrestrial (land snails) components of spring-fen biota, categorized as habitat specialists and other species (i.e. matrix-derived). Water temperature did not show a high level of correlation with mesoclimate. For all components, fractions of compositional variation constrained to temperature were statistically significant and higher for habitat specialists than for other species. The importance of air temperature at the expense of water temperature and its fluctuation clearly increased with terrestriality, i.e. from aquatic macroinvertebrates via vegetation (bryophytes and vascular plants) to land snails, with January air temperature being the most important factor for land snails and plant specialists. Some calcareous-fen specialists with a clear distribution centre in temperate Europe showed a strong affinity to climatically cold sites in our study area and may hence be considered as threatened by climate warming. We conclude that prediction models solely based on air temperature may provide biased estimates of future changes in spring fen communities, because their aquatic and semiterrestrial components are largely affected by water temperature that is modified by local hydrological and landscape settings.

Relict occurrences of boreal brown-moss quaking rich fens in the Carpathians and adjacent territories

Quaking rich fens dominated by boreal semi-aquatic brown-mosses such as Scorpidium scorpioides and Calliergon trifarium are extremely rare in the Carpathians. These fens harbour endangered species persisting at few localities in the region. However, their phytosociological classification has not been sufficiently solved yet, because they lack Sphagnum species as well as calcicole species characteristic for the Caricion davallianae alliance. A recent pan-European synthesis on fen vegetation suggests that these fens belong to the Stygio-Caricion limosae alliance (boreal rich fen vegetation). The isolated occurrence of this alliance southward of the boreal zone and outside the Alps is rather exceptional and might represent a relict from an early post-glacial period. In this study, we compared phytosociological data for the Stygio-Caricion limosae alliance between Northern Europe and the Carpathians plus adjacent regions (the Bohemian Massif, the Dinaric Alps) using NMDS and cluster analysis. We found that the species composition of brown-moss quaking rich fens in Central and Southeastern Europe corresponds well with that in Northern Europe, confirming their assignment to Stygio-Caricion limosae. We further reconstructed the potential past distribution of the alliance in Czech Republic and Slovakia using available floristic and macrofossil data. Macrofossil data suggest that this vegetation type had been much more common in Central Europe and that today it persists only in ancient fens, showing the long-term stability of environmental conditions. The main causes of its present-day rarity are Middle-Holocene woodland phases in fens and recent water table decreases caused by anthropogenic deterioration of the water regime in the landscape.

Refugial occurrence and ecology of the land snail Vertigo lilljeborgi in fen habitats in temperate mainland Europe

Vertigo lilljeborgi (Westerlund, 1871) is one of the rarest terrestrial snail species in temperate mainland Europe, where it is traditionally considered a glacial relict. This contrasts with its occurrence in northern Europe where it is a widespread species. This species prefers constantly wet habitats that are neutral to slightly acidic and avoids highly alkaline conditions, which is an extremely rare ecology for a Eurasian mollusc. Until 2012, only five historical records of this species were known in mainland Europe to the south of its main distribution in northern Europe. Since then, 20 new sites have been discovered, mostly located in the Hercynian Mountains (Bohemian Massif in the Czech Republic and Massif Central in France). In comparison with the boreal European and Alpine populations, those from the Hercynian Mountains inhabit acidic, rather soligenous and productive fens, strongly dominated by Sphagnum. Vertigo lilljeborgi does not occur in some sites with apparently suitable habitats as indicated by species composition of the vegetation. We observed a surprising correspondence between the occurrence of V. lilljeborgi and mean July air temperature and we report its first fossil record from the last glacial period from Central Europe. Although the number of its sites has increased recently, these sites represent highly unusual and unique habitats, vulnerable to drainage and destruction from human activities. This highlights the need for conservation efforts in most of the newly discovered isolated sites.

Bryophytes on river gravel bars in the Balkan mountains: new records and insights into ecology

Abstract: Kalníková, V., Palpurina, S., Peterka, T., Kubešová, S., Plesková, Z. & Sabovljević, M. 2017. Bryophytes on river gravel bars in the Balkan mountains: new records and insights into ecology. — Herzogia 30: 370 –386. Gravel bars are a heterogeneous habitat on the border between the aquatic and terrestrial environments that can maintain a high diversity of bryophyte species. However, the bryoflora of river gravel bar habitats has rarely been explored, particularly in Southeastern Europe. We therefore carried out a two-year field survey on river gravel bars in selected mountains and foothills in the Balkan Peninsula, recording all bryophytes in 4×4 or 3×5 m plots. In total, we sampled 59 vegetation plots on 30 streams and rivers and recorded 85 bryophyte taxa. Here we report Bryum klinggraeffii (a new species for the floras of Albania, Montenegro and Serbia) and five data-deficient or vulnerable species. We found several drought-tolerant bryophytes on gravel bars, e.g. Barbula convoluta, Ceratodon purpureus and Tortella tortuosa, as well as typical hygrophilous species, e.g. Cinclidotus aquaticus, Fontinalis antipyretica and Platyhypnidium riparioides. The most common species in this transitional habitat were Brachythecium rivulare, Bryum argenteum, Oxyrrhynchium hians, Barbula unguiculata, Ceratodon purpureus and Bryum caespiticium. Dentrended correspondence analysis ordination technique identified the complex gradient of moisture and light conditions as the main environmental factor for bryophyte communities on the studied gravel bars.

Arcto-Alpine Species at Their Niche Margin: the Western Carpathian Refugia of Juncus castaneus and J. triglumis in Slovakia

Juncus castaneus and J. triglumis are umbrella species of moist calcareous tundra and arctic-alpine initial fens (the Caricion atrofusco-saxatilis alliance), considered to be glacial relicts in the central-European Mts. Here we report new findings from the Western Carpathians (Slovakia). We analysed species composition of plant communities with the target Juncus species in a wide geographical context, using 20 available vegetation-plot records from the Carpathians, 711 records from other European regions, and formal definitions of fen alliances taken from a pan-European vegetation synthesis. The first gradient of non-metric multidimensional scaling (NMDS) differentiated alpine and arctic samples. The second principal gradient between Caricion atrofusco- saxatilis and other vegetation types was of similar importance. Records from the Western Carpathians assumed a marginal position in the gradient space, while records from the Eastern Carpathians (Romania) appeared to be similar to those from the Alps. Generally, Carpathian records did not match the formal definition of the Caricion atrofusco- saxatilis alliance. Although the arctic-alpine rush species persist occasionally in spring, fen and tundra microrefugia in the Carpathians, they do not belong in similar plant communities as in the Alps or in the Arctic.

Meesia triquetra, a New Relict Moss for the Republic of Macedonia

Abstract: Peterka, T., Plesková, T., Palpurina, S., Kalníková, V., Lazarević, P. M. & Hájek, M. 2016. Meesia triquetra, a new relict moss for the Republic of Macedonia. — Herzogia 29: 66–71. Meesia triquetra is a circumpolar boreo-arctic moss species typical for well preserved fens, and is rare in southern Europe. During field research on mire vegetation in the Balkan Peninsula, a population of Meesia triquetra was found at the Begovo pole wetland in the Jakupica Mountains. It is the first record of this species for the Republic of Macedonia. A description of the locality, ecological conditions and vegetation is presented. The moss grows here in the sedge-moss vegetation similar to temperate fens of the alliance Caricion davallianae. The vegetation with Meesia triquetra in Begovo pole was evaluated in the context of fen vegetation more generally in the Balkans using detrended correspondence analysis. The study site appeared to be similar to other Balkan calcium-rich brown-moss fens without calcium carbonate precipitation. This habitat resembles the optimum habitat of the species in central and northern Europe.

Pseudocalliergon lycopodioides, a New Bryophyte Species for Montenegro

Abstract: Peterka, T., Kalníková, V. & Plesková, Z. 2017. Pseudocalliergon lycopodioides, a new bryophyte species for Montenegro. – Herzogia 30: 496–500. Pseudocalliergon lycopodioides is an European boreo-temperate species confined to extremely rich fens and other calcareous wetlands. The species belongs to endangered wetland biota; many localities across Europe have recently disappeared. Pseudocalliergon lycopodioides is rare on the Balkan Peninsula. Here we report the species as new for Montenegro. The moss was found on the plateau Jezerska Površ at the eastern edge of the Durmitor Mts. Pseudocalliergon lycopodioides grows here in moss-sedge vegetation of the Caricion davallianae alliance.