Aim We investigated Quaternary range dynamics of two closely related but ecologically divergent species (cold-tolerant Edraianthus serpyllifolius and thermophilic Edraianthus tenuifolius) with ...overlapping distribution ranges endemic to the western Balkan Peninsula, an important yet understudied Pleistocene refugium. Our aims were: to test predictions of the ‘refugia-within-refugia' model of strong genetic subdivisions due to population isolation in separate refugia; to explore whether two ecologically divergent species reacted differently to Pleistocene climatic fluctuations; and to test predictions of the displacement refugia model of stronger differentiation among populations in the thermophilic E. tenuifolius compared with the cold-tolerant E. serpyllifolius. Location The western Balkan Peninsula. Methods We gathered amplified fragment-length polymorphism (AFLP) data and plastid DNA sequences from two to five individuals from 10 populations of E. serpyllifolius and 22 populations of E. tenuifolius, spanning their entire respective distribution areas. AFLP data were analysed using a Bayesian clustering approach and a distance-based network approach. Plastid sequences were used to depict relationships among haplotypes in a statistical parsimony network, and to obtain age estimates in a Bayesian framework. Results In E. serpyllifolius, both AFLP and plastid sequence data showed clear geographic structure. Western populations showed high AFLP diversity and a high number of rare fragments. In E. tenuifolius, both markers congruently identified a major phylogeographic split along the lower Neretva valley in central Dalmatia. The most distinct and earliest diverging chloroplast DNA (cpDNA) haplotypes were found further south in the south-easternmost populations. North-western populations, identified as a separate cluster by Bayesian clustering, were characterized by low genetic diversity and a low number of rare AFLP markers. Main conclusions Clear evidence for multiple Pleistocene refugia is found not only in the high-elevation E. serpyllifolius, but also in the lowland E. tenuifolius, despite the lack of obvious dispersal barriers, in line with the refugia-within-refugia model. Genealogical relationships and genetic diversity patterns support the hypothesis that cold-adapted E. serpyllifolius responded to climatic oscillations mostly by elevational range shifts, whereas thermophilic E. tenuifolius did so mainly by latitudinal range shifts, with different phases (and probably extents) of range expansion. In contrast to the displacement refugia hypothesis, the two elevationally differentiated species do not differ in their genetic diversity.
Mating system is one of the major determinants of intra- and interspecific genetic structure, but may vary within and between plant populations. Our study model included all known populations of ...Moehringia tommasinii (Caryophyllaceae), a narrow endemic plant inhabiting rock crevices in the northwestern Adriatic, and some populations of co-occurring and widespread M. muscosa, an ecologically divergent relative with an overlapping flowering period. We performed reciprocal crosses within and between taxa and used molecular markers to assess the extent of gene flow within and between populations and taxa. Using coefficient of inbreeding, population size, seed weight, pollen-to-ovule ratio, and flower display size, we also looked for evidence of a selfing syndrome.
A surprisingly high variation in mating systems was observed among populations of M. tommasinii. These populations exhibited genetic structuring, with their size positively correlated with both seed weight and pollen production. Although a selfing syndrome could not be confirmed as the majority of selfing resulted from allogamous treatments, the occurrence of selfing was notable. In the presence of M. muscosa, at a site where both species coexist closely, a distinct pattern of fruit production was observed in M. tommasinii following various pollination treatments. Molecular and morphometric data provided evidence of hybridization followed by local extinction at this site.
Population size proved to be the most important factor affecting the mating system in genetically structured populations of M. tommasinii. Lighter seeds and lower pollen production observed in populations with pronounced selfing do not provide enough evidence for the selfing syndrome. Detected gene flow between M. tommasinii and the sympatric M. muscosa suggested weak reproductive barriers between the taxa, which could pose a conservation problems for the former species. Hybridization leading to local extinction may also resulted in floral polymorphism and disruption of mating patterns of M. tommasinii.
Acidophytic alpine mat-grass swards are rare in the alpine belt of the predominantly calcareous Southeastern Alps of Slovenia, mostly occurring where limestone is admixed with marlstone or chert. ...Those for which we were able to make phytosociological relevés can be classified mainly into two syntaxa:
and
. At slightly lower elevations, in the forest zone of the subalpine plateau Pokljuka, we found similar swards occupying small areas in frost hollows with luvisol on limestone. They include character species of various subalpine-alpine sward and snow bed communities and are classified into the syntaxon
Abstract
This paper aims to shed light on distribution patterns and the relationship between species diversity and environmental heterogeneity of 17 Edraianthus taxa. We examined present and past ...distributions (Last Glacial Maximum) by applying ecological niche modelling. The environmental space occupied by the taxa was analysed using niche comparison methods. The results support the idea that the central and southern Dinaric Alps represent a centre of diversity and endemism in the western Balkan Peninsula. Diversity in Edraianthus is best explained by topographic (slope) and bioclimatic predictors (maximum temperature of warmest month, precipitation seasonality, precipitation of warmest quarter, precipitation of coldest quarter), suggesting that mountain areas with the most diversified relief have higher diversity. Niche modelling results suggest considerable range dynamics during the climatically unstable Quaternary. Thermophilic and lowland taxa responded with longitudinal shifts to ecologically suitable areas farther south, whereas high-mountain taxa responded mainly with elevational shifts. The greatest niche similarity is found among phylogenetically closely related taxa and among ecologically similar and often sympatric taxa. The least similarity was observed in species with marked differences in habitat elevation and in more geographically isolated species. Our results suggest that the extent of range and niche overlap varied among some taxa throughout their evolutionary history, which may have led to diversification at both allopatric and sympatric levels. The correlation between the genetic diversity of the most widespread taxon and the richness of taxa could be a consequence of past and present contacts. On the other hand, alternate periods of isolation may have favoured the emergence of taxa that are reproductively isolated and ecologically specialized.
The high-biodiversity phenomenon of the Balkan Peninsula is a result of the past and present topographic, climatic and geological conditions, as well as human impact. The Dinaric Alps, as a part of ...the Balkan Peninsula, harbour a high number of endemic species, some of them comprising a small number of populations, which are often endangered. We investigated spatial distribution, community composition, site ecology, genetic diversity and conservation of
Degenia velebitica
, a stenoendemic species of the north-western Dinaric Alps. Our results showed that
D. velebitica
is nowadays restricted to three localities with the area of occupancy of 48,560 m
2
, harbouring approximately 37,000 individuals.
Degenia velebitica
stands are differentiated into three well-characterized, floristically homogenous syntaxa, very distinct from the surrounding vegetation, suggesting their azonal occurrence and restriction to spatially highly fragmented microsites exposed to stormy winds. Spatial distances of populations, differences in
D. velebitica
community composition and site ecology are mirrored in genetic variation patterns of the populations, such as high-frequency down-weighted marker values in the north-western populations and high gene diversity in the south-eastern group of populations. The fact that we could not find a single
D. velebitica
individual at the
locus classicus
indicates the existence of the ever-growing fragmentation. The analyses of genetic structure using AFLP data recognized two main genetic groups of populations as evolutionary significant units that should be considered when planning protection measures. According to our IUCN Red List reassessment,
D. velebitica
should be treated as a critically endangered species that requires immediate conservation actions.
Due to strong spatial heterogeneity and limited Pleistocene glaciation, the Balkan Peninsula is a major European biodiversity hot spot. Surprisingly little, however, is known about patterns and ...processes of intraspecific diversification of its biota in general and of high‐altitude species in particular. A well‐suited system to test hypotheses with respect to various isolating factors acting at different geographic scales and to explore full‐range phylogeographic patterns on the Balkan Peninsula is Edraianthus graminifolius (Campanulaceae), distributed in the western Balkan mountain systems, the southwestern Carpathians and the Apennine Peninsula. To this end, we used a dense population sampling and employed amplified fragment length polymorphism (AFLP) markers and plastid DNA sequences supplemented by ecological niche modelling. The strongest splits were inferred to separate southern and northern Balkan populations from the central ones, from where range extension occurred to the Carpathians and, in more recent times, once or twice to the Apennine Peninsula. The three genetic groups in the western Balkan Peninsula were remarkably congruent among molecular markers, suggesting that the barriers to gene flow acted over long time periods facilitating allopatric differentiation. Each main group of Balkan populations contained genetically and geographically distinct subgroups, which likely are the result of local refugia during warmer periods. Evidently, the topographically highly complex and during the Last Glacial Maximum only locally glaciated Balkan Peninsula is a hot spot of species richness and endemism as well as a sanctuary of intraspecific genetic diversity, even if the underlying causes remain insufficiently understood.
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
The genus Wulfenia (Plantaginaceae) demonstrates a striking disjunction between the southeastern Alps (Carnic Alps), the southeastern Dinaric Alps (Prokletije Mountains, Balkan Peninsula) and the ...Amanos mountains of southern Turkey. This puzzling biogeographic pattern has interested botanists for more than 100 years and Wulfenia has been widely regarded as a Tertiary relict of at least Miocene age in southeastern Europe. Specifically, the identity of populations in the Prokletije Mountains either referred to as disjunct populations of W. carinthiaca or a separate species, “W. blecicii”, has been much debated. Here we analyze AFLP, plastid and nuclear ribosomal sequence data in conjunction with a morphometrical analysis to clarify the taxonomy of the genus and the relationships of the populations to one another. Furthermore, we employ a molecular dating strategy to put these results in a time frame to assess the Miocene relict–hypothesis. Our results provide evidence for a new classification of the genus with four species, W. orientalis, W. glanduligera comb. & stat. nov., W. baldaccii and W. carinthiaca. The split of the last species into populations disjunctly distributed in the southeastern Alps (W. carinthiaca s.str.) and southeastern Dinaric Alps (“W. blecicii”), is not supported either by molecular or morphological data, while we find enough evidence in DNA sequence data, growth site specifics and morphology for W. orientalis var. glanduligera to be treated at the species rank. Our dating analysis suggests that the extant genus is rather young with a crown node age of only about 1.24 Ma and 0.61 Ma for the European populations despite a stem node age of about 10.69 Ma. Thus, Wulfenia as a genus is likely a Miocene relict but its uninterrupted presence on the Balkan Peninsula cannot be demonstrated.
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 rangewide 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. denscanis. 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. denscanis 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.
Range contraction and habitat fragmentation can cause biodiversity loss by creating conditions that directly or indirectly affect the survival of plant populations. Fragmented habitats can alter ...pollinator guilds and impact their behavior, which may result in pollen/pollinator limitation and selection for increased selfing as a mechanism for reproductive assurance. We used Salvia brachyodon, a narrowly distributed and endangered sage from eastern Adriatic, to test the consequences of range contraction and habitat fragmentation. Molecular data indicate a severe and relatively recent species range reduction. While one population is reproductively almost completely isolated, moderate gene flow has been detected between the remaining two populations. The high pollen-to-ovule ratio and the results of controlled hand pollination indicate that S. brachyodon has a mixed mating system. Quantitative and qualitative differences in the community and behaviour of flower visitors resulted in limited pollination services in one population where no effective pollinator other than pollen and nectar robbers were observed. In this population, self-pollination predominated over cross-pollination. Various environmental factors, in which plant-pollinator interactions play a pivotal role, have likely created selection pressures that have led to genetic and phenotypic differentiation and different resource allocation strategies among populations.
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