Petra Hájková

Spring fen vegetation and water chemistry in the western carpathian flysch zone

In the western part of the Carpathian flysch zone, aquifers host several springwater chemistry types. Four vegetation types, distinguished along the poor-rich gradient (tufa-forming and peat forming brown moss fens, moderately rich and poorSphagnum fens), have been compared with respect to the main habitat factors. Water calcium and magnesium concentrations, pH and conductivity as well as the soil organic carbon content were the properties measured that showed the strongest correlation with the main vegetation gradient (the poor-rich gradient). Further, significant differences in iron, sodium, potassium, sulphate and phosphate concentrations were also found between pairs of related vegetation types. The range of calcium concentrations is wide (2–300 mg/l). The calcium concentration in tufa-forming springs is higher than values usually reported from northern and western Europe. Tufa formation is influenced not only by high calcium concentrations, but also by the total chemical composition of springwater and both climatic and topographic conditions. There is a great excess of cations over Cl− and SO 4 2− , balanced by HCO 3 − and CO 3 2− in springs with the most intense tufa precipitation. Unusually high calcium concentrations combined with high iron concentrations were found in peat-forming brown moss fens. RichSphagnum-fens with calcitolerantSphagnum species are distinctively low in phosphates. The Western Carpathian poor fens dominated bySphagnum flexuosum have water and soil calcium concentrations comparable to those reported from rich fens of some other areas. The springwater of these fens are rich in iron, phosphates and sulphates. The poorest spring fens withSphagnum fallax, S. magellanicum, S. papillosum andS. auriculatum are not only poor in calcium, but also in iron, sodium and potassium.

Diversity of wetland vegetation in the Bulgarian high mountains, main gradients and context-dependence of the pH role

We fill a gap in understanding wetland vegetation diversity and relationship with environmental determinants in Bulgarian high mountains. A total of 615 phytosociological samples were taken from springs, mires, wet meadows and tall-forb habitats throughout Bulgaria, of which 234 relevés are from mire and spring vegetation above timberline. The vegetation was classified by TWINSPAN and the resulting vegetation types were reproduced by the formal definitions using the combination of Cocktail species groups based on phi-coefficient of joint co-occurrence of the species. Nine vegetation types of springs and fens have been clearly delimited above the timberline. All vegetation types include Balkan endemic species, the representation of which varies. Fens generally harbour more Balkan endemics than do springs, with the exception of species-poor high-altitude Drepanocladetum exannulati. The gradient structure of the vegetation was revealed by DCA and by CCA with forward selection of environmental factors. The major determinants of vegetation variation strongly differ above and below the timberline and likewise between springs and fens. The base-richness gradient controls the floristic variation of Bulgarian submontane fens, whereas the complete data set including both submontane and subalpine fens is governed by the altitude gradient from lowland and basin fens to subalpine fens rich in Balkan endemics. When focusing on sites above the timberline only, the first DCA axis separates fens from springs without organic matter. The major species turnover in springs follows the variation in water pH and mineral content in water, whereas fen vegetation variation is primarily controlled by succession gradient of peat accumulation. Altitude remains an important factor in all cases. Weak correlation between water pH and conductivity was found. This correlation was even statistically insignificant in fens above the timberline. Water pH is not influenced by mineral richness in Bulgarian high mountains, since it is buffered by decomposition of organic matter in fens. In springs, pH reaches maximum values due to strong aeration caused by water flow. The plant species richness decreases significantly with increasing altitude. The increase of species richness towards circumneutral pH, often found in mires, was not confirmed in Bulgarian high mountains. The correlation between species richness and pH was significant only when arctic-alpine species and allied European high-mountain species were considered separately. The richness of boreal species was independent on pH. Some of them had their optima shifted to more acidic fens as compared to regions below the timberline. Our results suggest that subalpine spring and fen vegetation should be analysed separately with respect to vegetation-environment correlations. Separate analysis of fens below and above timberline is quite appropriate.

Bryophyte and vascular plant responses to base-richness and water level gradients in Western CarpathianSphagnum-rich mires

We investigated the importance of water chemistry and water regime for vascular plant and bryophyte species distribution in Western Carpathian mires dominated bySphagnum. Seventy-seven small circle plots distributed across a wide geographical area, a wide range of mineral richness and all possible microtopographical features were sampled in terms of species composition, physical-chemical water properties and water regime during one growing season. Both water chemistry and water regime were found to be important factors for vegetation composition. Bryophytes reflected only one clear gradient, connected to base-richness (pH, conductivity) and maximal water-level, whereas three different environmental gradients determined the occurrence of vascular plants: water-level amplitude, base-richness and an indistinct gradient presumably connected to peat layer thickness. When the entire data set was subjected to DCA ordination, the first resulting axis was governed by the bryophyte subset, whereas the second one was governed by the vascular plant subset. The species density of vascular plants was positively correlated with pH and conductivity. On the contrary, bryophyte species density showed no relationship to environmental factors. We further compared the pH values measured in groundwater and in water squeezed from bryophytes from the same plot; these plots were distributed along the base-richness gradient. Only in the acidic mires did the use of squeezed-water chemistry in the analyses give results similar to the use of groundwater pH. Further, we found thatSphagnum species with a similar response to the base-richness gradient had differentiated niches with respect to the water level gradient and vice versa.Sphagnum contortum andS. warnstorfii exhibiting the same demands for groundwater pH were segregated along the gradient of maximum water level. An analogous pattern was detected for acidophilous speciesSphagnum magellanicum andS. papillosum.

The age of island-like habitats impacts habitat specialist species richness.

While the effects of contemporaneous local environment on species richness have been repeatedly documented, much less is known about historical effects, especially over large temporal scales. Using fen sites in the Western Carpathian Mountains with known radiocarbon-dated ages spanning Late Glacial to modern times (16 975-270 cal years before 2008), we have compiled richness data from the same plots for three groups of taxa with contrasting dispersal modes: (1) vascular plants, which have macroscopic propagules possessing variable, but rather low, dispersal abilities; (2) bryophytes, which have microscopic propagules that are readily transported long distances by air; and (3) terrestrial and freshwater mollusks, which have macroscopic individuals with slow active migration rates, but which also often possess high passive dispersal abilities. Using path analysis we tested the relationships between species richness and habitat age, area, isolation, and altitude for these groups. When only matrix-derived taxa were considered, no significant positive relation was noted between species richness and habitat size or age. When only calcareous-fen specialists were considered, however, habitat age was found to significantly affect vascular plant richness and, marginally, also bryophyte richness, whereas mollusk richness was significantly affected by habitat area. These results suggest that in inland insular systems only habitat specialist (i.e., interpatch disperser and/or relict species) richness is influenced by habitat age and/or area, with habitat age becoming more important as species dispersal ability decreases.

Distribution of diatoms and bryophytes on linear transects through spring fens

The distribution of bryophytes and their diatom epiphytes was studied in three acidic, mineral-poor spring fens in the Western Carpathian flysch zone (Czech Republic, Slovak Republic). Samples were taken along linear transects from the permanently wet surrounding of streams to the dry Sphagnum - and Polytrichum-hummocks. The height above the water table and water content of each moss sample were measured. Moisture and pH were found to be primary factors influencing moss and diatom species distribution. Diatom abundance, species richness and diversity decreases with the decreasing moisture in the microsite. Eunotia paludosa was a typical species of dry hummock tops, accompanied by Pinnularia rupestris and Achnanthes lanceolata. Diatom-species-rich streams were characterized by the occurrence of Eunotia arcus, E. incisa and Pinnularia subcapitata. Significant relationships were found between the occurrence of some mosses and diatom species composition, independent from the measured moisture characteristics.

Formation, succession and landscape history of Central-European summit raised bogs: A multiproxy study from the Hrubý Jeseník Mountains

Central-European raised bogs, developed on mountain summits, are specific ecosystems of high conservation importance, but their history remains largely unknown. Pollen, macrofossils, testate amoebae and peat characteristics were analysed in a peat sequence of the Vozka bog (Hrubý Jeseník Mountains, Eastern Sudetes, Czech Republic). Past water chemistry and water-table depths were reconstructed by transfer functions calibrated from recent testate amoeba data and long-term environmental averages. Peat initiation started in the middle Holocene (approximately 4200 bc) by the process of paludification, resembling the development of Atlantic blanket bogs. Around 100 bc the vegetation changed from Eriophorum vaginatum-poor fen to the ombrotrophic-bog vegetation similar to the recent situation. A hiatus in peat sequence was revealed between ad 1320 and 1954. It can be explained either by human activities, or by an extreme drought causing decomposition of previously accumulated peat. Local bog development was largely independent of landscape development inferred from pollen records. In the middle Holocene, mixed spruce-elm-hazel woodland was recorded close to the treeline. During 2400–800 bc a gradual transition to mixed spruce-fir woodlands with admixture of beech took place, and from approximately 800 bc spruce and fir became dominant. The major human impact started approximately ad 1230 and was connected with settlement and mining in the foothills.

Sphagnum distribution patterns along environmental gradients in Bulgaria

Abstract The distribution patterns of 18 Sphagnum species along base-richness and altitudinal gradients were studied in Bulgarian treeless wetlands which are noteworthy because of the edge-of-range occurrence of many mire species including Sphagnum. Of 483 spring and mire sites studied, 202 samples contained some Sphagnum species. The most common species were S. subsecundum (n=85), S. platyphyllum (46), S. contortum (41), S. teres (40) and S. capillifolium (26). The significance of Sphagnum responses to environmental gradients was tested by comparing generalized additive models against the null model. Many Sphagnum species displayed a significant response to the altitudinal gradient. Several species were clearly linked to low or to high altitudes, but the realized niche of other species was wide with respect to altitude. Most species significantly responded to water pH, both above and below the timberline. The same result was obtained for water conductivity below the timberline, whereas only a few species had a significant response to conductivity above the timberline. The highest water conductivity under which Sphagnum species occurred was 280 μS cm−1. Sphagnum contortum was the species occupying the mires with the highest mineral content. On the contrary, Sphagnum warnstorfii, one of the most calcitolerant species in many regions of Europe, often occurred in extremely mineral-poor mires above the timberline. Some other Sphagnum species growing in mineral-rich mires below the timberline, also inhabited extremely mineral-poor mires above the timberline. This could be explained by adaptation to local conditions during long-term isolation on mineral-poor bedrock or by changed competition pressure.

New national and regional bryophyte records, 36

ub lis he d by M an ey P ub lis hi ng ( c) B rit is h B ry ol og ic al S oc ie ty Bryological Notes New national and regional bryophyte records, 36 L T Ellis, V A Bakalin, E Baisheva, H Bednarek-Ochyra, R Ochyra, E A Borovichev, S S Choi, B-Y Sun, P Erzberger, V E Fedosov, R Garilleti, B Albertos, P Gorski, P Hajkova, N G Hodgetts, M Ignatov, A Koczur, L E Kurbatova, M Lebouvier, A Mežaka, J Miravet, P Pawlikowski, R D Porley, J A Rossello, M S Sabovljevic, J Pantovic, A Sabovljevic, W Schroder, S Ştefănuţ, G M Suarez, M Schiavone, O T Yayintas, J Vaňa The Natural History Museum, London, UK, Botanical Garden-Institute, Vladivostok, Russia, Institute of Biology and Soil Science, Vladivostok, Russia, Institute of Biology of Ufa, Scientific Centre of Russian Academy of Sciences, Ufa, Russia, Institute of Botany, Poland, Polar-Alpine Botanical Garden-Institute, Kirovsk, Russia, Chonbuk National University, Jeonju, Korea, Berlin, Germany, M.V. Lomonosov Moscow State University, Russia, Universidad de Valencia, Burjassot, Spain, Poznan University of Life Sciences, Poland, Masaryk University, Brno, Czech Republic, Institute of Botany, Brno, Czech Republic, Earlish, Isle of Skye, UK, Main Botanical Garden, Moscow, Russia, Institute of Nature Conservation, Krakow, Poland, Komarov Botanical Institute, Russia, Universite de Rennes 1, France, University of Latvia, Riga, Latvia, Marimurtra Botanical Garden, Catalonia, Spain, University of Warsaw, Poland, Cerca dos Pomares, Portugal, Universidad de Valencia, Spain, University of Belgrade, Serbia, Ludwigsstadt, Germany, Institute of Biology of Romanian Academy, Bucharest, Romania, Facultad de Ciencias Naturales e I.M.L., Tucuman, Argentina, Canakkale Onsekiz Mart University, Biga, Canakkale, Turkey, Charles University, Praha, Czech Republic

The Balkan wet grassland vegetation: a prerequisite to better understanding of European habitat diversity

The knowledge of broad-scale floristic variation in wet grasslands, which are endangered throughout Europe, is still limited and some regions have remained unexplored so far. In addition, hitherto published phytosociological studies were concentrated at the national level and therefore national vegetation classifications are not consistent with each other. In order to overcome these shortcomings of traditional phytosociology, we gathered original data from Bulgaria and analysed them together with the data from Central Europe. We further analysed major compositional gradients within Bulgarian wet grasslands and changes in species richness along them. We sampled 164 wet grassland vegetation plots throughout Bulgaria. We further prepared a restricted data set of wet grasslands from Central-European phytosociological databases. Both data sets were merged and classified by modified TWINSPAN. Four distinct vegetation types were differentiated. Even if they correspond with traditional alliances, which are primarily drawn as geographically defined units in Western and Central Europe (sub-Mediterranean Trifolion resupinati, sub-continental Deschampsion cespitosae and Molinion caeruleae and sub-oceanic Calthion palustris), they all occur in Bulgaria. When more precise classification was applied, two types of sub-Mediterranean wet grasslands and one high-altitude type of Calthion grasslands were detected solely in Bulgaria. DCA analysis showed that altitude is a dominant gradient controlling variation in Balkan wet grasslands. The second DCA axis was interpreted as the gradient of nutrient availability. Species richness shows skewed-unimodal trends along both major gradients, with the highest species richness in intermittently wet nutrient-limited grasslands. Tukey post-hoc test of altitudinal differences amongst vegetation types is significant for all pairs of clusters, suggesting that altitudinal differentiation is responsible for co-occurrence of nearly all European types of wet grasslands in Bulgaria. Our results suggest that (1) climate is an important factor for the diversity of wet grasslands; (2) Balkan vegetation of middle altitudes matches with that of Central Europe, whereas that of the lowest altitudes corresponds rather to the sub-Mediterranean region and high mountains are specific; (3) upward shift of Central-European vegetation types in southern Europe, so often described in forest vegetation is also evident for grassland vegetation and (4) the high diversity of Balkan vegetation is determined by a diverse relief enabling confluence of habitats possessing different climatic conditions.

New national and regional bryophyte records, 13

New national and regional bryophyte records, including new data from Bulgaria gathered during GAAV project.