Boštjan Surina

Delimitation of the alliances Caricion firmae (Seslerietalia albicantis) and Seslerion juncifoliae (Seslerietalia juncifoliae) in the southeastern Alps and Dinaric mountains

Abstract A syntaxonomic and phytogeographic delimitation of the calcareous open sedge swards in the alpine belt of the Alps (Caricion firmae) and subalpine and alpine tussock grasslands in wind-exposed habitats (Seslerion juncifoliae) in the area of the south-eastern Alps and of the Dinaric mountains was performed. Analyses based on hierarchical classification, ordination and chorology clearly showed the distinction between the syntaxa: stands from the Liburnian karst (Mt Snežnik – SW. Slovenia, Mts Risnjak and Snježnik – NW. Croatia), Lička Plješivica and the Velebit mountains belong to the Dinaric alliance Seslerion juncifoliae, whereas stands from the Trnovski gozd plateau (W. Slovenia, north-westernmost part of the Dinaric mountains), although somewhat transitional between the two alliances, and stands from the Alps, were classified in the alliance Caricion firmae. The alliance Seslerion juncifoliae of the Dinaric mountains vicariates Caricion firmae of the Alps.

Snowbed vegetation in Croatia: Phytosociology, ecology and conservation status

Abstract Phytosociology, ecology and chorology of snowbed vegetation in Croatia were researched. Snowbed stands, found only in freezing ravines and dolines of the Liburnian karst and Velebit Mountains (NW Dinaric Alps, NW Croatia), were classified into the association Drepanoclado-Heliospermetum (Salicion retusae, Arabidetalia caeruleae, Thlaspietea rotundifolii). Those stands, exposed mostly to the north and shaded for the majority of the growing season, were developed on more or less settled periglaciar screes and boulders in the coldest parts (bottoms, smaller ditches) of the dolines with long-lasting snow cover. Due to lower altitude of Croatian mountains, snowbed vegetation could be found only azonally, in freezing ravines surrounded by altimontane and subalpine (fir-)beech and spruce forests, where these stands manage to thrive due to specific microclimatic conditions. Snowbeds host some rare, endangered and/or protected plant species in Croatia. Vulnerability of the flora and vegetation of snowbeds in Croatia is briefly discussed.

Patterns of plastid DNA differentiation in Erythronium (Liliaceae) are consistent with allopatric lineage divergence in Europe across longitude and latitude

Little attention has been paid so far to the genetic legacy of the oceanic-continental gradient across Europe. Due to this gradient, steppe regions become more extensive and mesic environments become more scattered towards the East. A well-suited system to study the impact of this gradient on lineage differentiation is the temperate mesophilic plant Erythronium dens-canis (Liliaceae), which is widespread in southern Europe with a distribution gap in the Pannonian Plain. Moreover, the large disjunction between E. dens-canis and its sister species E. caucasicum coincides with the Pontic steppe region. By applying range-wide sampling of E. dens-canis and limited sampling of E. caucasicum, we explored their phylogeography using the plastid regions rpl32-trnL and rps15-ycf1. Three major phylogroups were identified: a Caucasian lineage, a highly structured and narrowly distributed Transylvanian lineage, and a more homogenous and widely distributed ‘non-Transylvanian’ lineage. Apparently, both physiographic (mountain) and climatic (steppe) barriers have caused allopatric differentiation in European Erythronium. The Southern Carpathians constitute a latitudinal barrier and the Pannonian Plain a longitudinal barrier between the Transylvanian and ‘non-Transylvanian’ lineages of E. dens-canis. The eastern Carpathian Basin likely functioned as a combination of cryptic eastern (mesic) and cryptic northern refugia for E. dens-canis during glacial periods. The Eastern Carpathians and particularly the Pontic steppe regions acted as a longitudinal barrier between E. dens-canis and E. caucasicum. Steppe-dominated gaps in the distribution range of Erythronium are mirrored by genetic discontinuities along longitudes; this highlights the important role of the oceanic-continental gradient throughout Europe for lineage differentiation.

Heaths with dwarf ericaceous shrubs and Alpine juniper (Juniperus alpina) in the Dinaric Alps: A nomenclatorial and synsystematic re-appraisal

Abstract The ecology and phytosociology of north-western Dinaric heaths of the association Rhododendro hirsuti-Juniperetum alpinae Horvat ex Horvat et al. 1974 nom. corr. prop. as well as the syndynamics and synsystematics of heaths in the Dinaric Alps are discussed. While the structure (physiognomy) of these stands is very homogenous and dominated by few species, the flora is heterogeneous, since ecotonal areas, where heaths are most frequently developed, represent a contact zone of elements of different syntaxa. Due to an abrupt reduction in pasture activities strong encroachments of shrubs and trees have become common, which additionally contribute to the floristic heterogeneity of the heaths. Although the identification and circumscription together with synecology and synchorology of heaths in general are more or less easily understood and straightforward, their floristic affinities, in relation to structure homogeneity and syndynamics, are complicated, which led to the proposal of several synsystematic schemes depending on interpretation of the relationship between flora and structure of stands. Dinaric heaths are classified into three classes, Erico-Pinetea, Vaccinio-Piceetea and Festuco-Brometea and a classification scheme is proposed together with nomenclatorial revision of the analyzed heaths with dwarf ericaceous shrubs and Alpine juniper (Juniperus alpina) in the Dinaric Alps

Ecology and niche assembly of Campanula tommasiniana, a narrow endemic of Mt Učka (Liburnian karst, north-western Adriatic)

Abstract Campanula tommasiniana is a typical chasmophyte occupying calcareous rock crevices and cracks along a wide range of ecological gradients, demonstrating a high degree of ecological plasticity and stress tolerance with regards to abiotic factors. Generally, three ecologically and floristically distinct groups of stands were recognized and typified according to a sigmatistic approach: (a) Seslerio juncifoliae-Campanuletum tommasinianae ass. nov., with stands occupying higher elevated sites fully exposed to sun and strong winds; (b) Seslerio autumnalis-Campanuletum tommasinianae ass. nov., representing stands predominantly developed within thermophytic beech stands, semi- to fully- -shaded by the tree canopy; (c) Cystopteri fragilis-Campanuletum tommasinianae, sciophytic, stands adapted to moisture and coldwith high frequency and coverage of bryophytes. Results of DCA analyses using a unimodal model suggest that Campanula tommasiniana is primarily a plant of open and exposed sites of higher elevation despite being most frequently found in rock crevices within thermophytic and altimontane beech forests.

Seed dormancy and germination of the rare, high elevation Balkan endemic Cerastium dinaricum (Caryophyllaceae)

Short or long-term ex situ conservation is becoming increasingly important in conservation of plants in today’s changing environments. One of the important steps in ex situ conservation is the collection and storage of seeds and the consequent establishment of seed germination protocols. Cerastium dinaricum (Caryophyllaceae) is an endemic, high elevation and rare species of European conservation concern. Because of its severely fragmented distribution along the Dinaric Alps, the populations are likely to undergo further shrinkage in the future, which addresses the need of a long-term effective conservation management. From the potential ex situ population management perspective, we focused our study on germination ecology of C. dinaricum. The study revealed that temperature considerably affected the germination of seeds, which germinate better at 20xa0°C rather than 10xa0°C. A period of cold-wet stratification also significantly improved the final germination percentage with more pronounced increase at 20xa0°C, while addition of GA3 increased the final germination percentage by breaking the dormancy of non-stratified seeds. Mechanical scarification did not improve germination; on the contrary, it resulted in the lowest germination success. Seeds grown in complete darkness germinated significantly better compared to control when they were exposed to cold-wet stratification. Contrary to previous studies on some alpine species, which germinate better when exposed to light, dark treatment resulted in the highest germination percentages with 70 and 90% germination success after 4 and 8xa0weeks of stratification, respectively.

Chasmophytes on screes? A rule and not an exception in the vegetation of the Karst (southwest Slovenia)

Abstract We investigated the community ecology and autecology of chasmophytes in the Karst (southwest Slovenia). An unusually massive occurrence of chasmophytes on settled screes and rock falls was detected in some of the collapse dolines of Škocjan Caves and surroundings, building floristically and physiognomically homogenous plant communities. At first sight, no significant floristic distinctions in vascular plants were observed between scree and rock crevice stands, despite striking differences in habitats. A detailed floristic survey of stands, including vascular plants and bryophytes, as well as ecological parameters, revealed four distinct vegetation types. Floristically, bryophytes proved to differentiate groups of stands excellently but, in contrast to vascular plants, their presence and abundance only poorly reflected site conditions. Among chasmophytes, which, in terms of the Braun-Blanquet approach in phytosociology, are assigned to the class Asplenietea trichomanes (sensu Braun-Blanquet and Oberdorfer), only Saxifraga petraea and Saxifraga tridactylites prefer rock crevices and artificial walls, respectively, while others, e.g., Saxifraga crustata, Primula auricula and Athamanta turbith, prefer screes and their habitat selection is governed by different ecological parameters, shaped primarily by the phenomenon of temperature inversion in collapse dolines.