Alpine Botany最新文献

Pollination success and seed production of clonal plants will depend on the clonal structure of local populations if it affects the degree of geitonogamous pollination. We compared the clonal structure and reproductive performance of an alpine dwarf shrub, Rhododendron aureum, between local populations with different snowmelt conditions in the Taisetsu Mountains of northern Japan. This species is an outcrosser and many self-fertilised ovules are aborted before maturation. Flowering at early snowmelt sites (fellfield and shrubby habitats) occurs in mid-June, when overwintered bumble-bee queens are the major pollinators, whereas flowering at late snowmelt sites (snowbed habitat) occurs after mid-July, when bumble-bee workers are the main pollinators. Fruit-set rates were larger in the early-flowering populations than in the late-flowering populations due to larger queen abundance than usual years. However, seed production in ripe fruits differed between the habitat types in the early-flowering populations, where fellfield population with continuous patch distribution showed higher seed production than shrubby population with fragmented patch distribution. It was supposed that frequent geitonogamous pollination in the fragmented population resulted in higher abortion of self-fertilised seeds. Flower number per inflorescence was similar between flowering times, but ovule number per flower was significantly higher in the early-flowering populations than in the late-flowering populations. The production of many ovules was expected to be advantageous for the early-flowering population to ensure the seed production in environments with fewer flower visitors in usual years. In conclusion, heterogeneous ecological situations in the alpine ecosystem lead to habitat-specific seed production pattern among conspecific populations.

Many species of river riparia are threatened by habitat loss due to altered flood and sediment regime, and associated shifts in vegetation structure. However, their ecological niche is often obscure, especially in inconspicuous organisms such as lichens, hindering their conservation and use as indicator species in river restoration. We studied if variation in sediment size distribution, gravel bank elevation and vegetation structure drive presence-absence and fertility (fruit body production) in the endangered, soil-dwelling lichen Stereocaulon incrustatum along two Swiss braided rivers, using binomial generalized linear mixed effect models in a Bayesian framework. Data was sampled on 811 plots randomly placed along 41 transects perpendicular to the main channels. Presence probability was highest on the most elevated plots, at 30% vascular plant cover in the herb layer, and 30–40% cobble cover, and increased with moss cover. Fruit body production probability was highest under closed canopies of woody plants > 3m. We show that in braided rivers, S. incrustatum is most likely found on elevated, coarse-grained sediments with increased moss but moderate vascular plant cover. This indicates a niche comprising relatively stable riparian environments, where a dry, cryptogam-dominated vegetation establishes on raw soils and competition with vascular plants is moderate. Fertile thalli are mostly found under closed canopies and high densities, suggesting a shift to sexual reproduction with increasing habitat age. While rare but strong disturbances are therefore necessary for habitat creation, older, densely populated habitat patches may harbor important source populations for colonization, thereby representing focal areas for conservation.

Plants along mountain slopes experience strong environmental variation, particularly declining air temperature with increasing elevation. Investigating intraspecific variation in morphological traits and biomass allocation across elevational gradients can reveal how plants adjust their life-history strategies to climatic conditions, improving our understanding of their resilience to climate change. We analysed variation in overall morphology and biomass allocation in two high-elevation species: Campanula alpina and Doronicum stiriacum, both centred in the alpine belt. Their elevational responses were compared with three species exhibiting wider elevational occurrence: Soldanella carpatica (lower montane to subnival belt), Bellidiastrum michelii (lower montane to alpine belt), and Senecio subalpinus (lower montane to subalpine belt). All five species showed decreasing plant height with increasing elevation. However, high-elevation species maintained stable aboveground biomass and reproductive allocation, while species with wider elevational occurrence exhibited more than 50% reduction in aboveground biomass, and two of them showed significant decline in flower biomass with elevation. Our findings confirm that species with wider or lower elevational ranges exhibit greater trait variation than high-elevation specialists. These patterns suggest that mountain generalist species, with lower elevational preferences and wider elevational occurrence, may respond more strongly to rising temperatures, potentially increasing aboveground biomass and plant height under future climate change. In contrast, high-elevation species demonstrated the ability to persist across a wide temperature range while maintaining stable biomass, indicating physiological tolerance and potential to withstand warming in alpine environments. Further research is needed to understand how high-elevation specialists maintain stable growth and reproductive output, particularly their eco-physiological adaptations.

The adaptive responses of Espeletia standleyana and E. santanderensis populations in a paramo in Northeastern Colombia (3350 m a.s.l.), were studied to characterize their spatial segregation. Their anatomical, morphofunctional and leaf biomass characteristics were determined and compared. We found that many traits such as depth of the stomatal crypts, number of vascular bundles, leaf and peduncle xylem vessel diameters, thickness of the mesophyll, leaf area, rosette height and diameter, leaf water content, leaf area index, and leaf biomass were significantly higher in E. standleyana (P< 0.05). Meanwhile, the diameter of the vascular bundles, width of stomatal crypts, number of leaves, specific leaf area, and percentage of sclerophylly were higher in E. santanderensis (P<0.05). Multifactorial segregation indicated highly differential expressions in their morphofunctional and leaf biomass characteristics, evidencing adaptations to their microhabitats. E. standleyana showed xeromorphic characters in response to the greater ambient fluctuations typical of the paramo, while E. santanderensis responded with scleromorphic traits related to lower soil organic matter and water content, characteristic of the high Andean forest-paramo ecotone. The high spatial heterogeneity of the paramos allows the development of microclimatic and edaphic mosaics that determine population segregation of these growth forms.

Apomictic plant taxa often show latitudinally and elevationally larger distribution ranges than their sexual relatives and tend to colonize previously glaciated areas more frequently. Despite numerous studies, the impact of the environment on this phenomenon is not fully understood. The present common-garden experiment on the alpine model plant Ranunculus kuepferi, with diploid sexual populations restricted to the south-western European Alps and tetraploid apomicts widespread throughout the Alpine Arc, should reveal how the cytotypes respond to the increasingly colder climate along a 1000 m elevation transect from the subalpine to the subnival zone in the Austrian Alps. Individuals originating from different populations in the European Alps were transplanted to plots at 4 elevations, and growth, leaf freezing resistance and reproductive fitness were recorded during the following 3 years. Additional measurements were carried out in natural populations. Diploids and tetraploids differed in their response to the respective site conditions along the elevation transect. Sexuals performed equal or even better than apomicts also at the highest site. Otherwise, tetraploids showed features, which could be advantageous in a cold climate: leaf mass per leaf area and rhizome mass increased with elevation, higher leaf freezing resistance, and larger diaspores prone to persist in seed banks. These traits, in combination with other factors, may have facilitated the postglacial establishment of tetraploids in higher regions of the Alps. The results suggest that both different responses to site conditions and different modes of reproduction may have led to the cytotype-specific geographical distribution patterns.

Cushion plants, which dominate nival ecosystems, are known to host a large diversity of plant, microbe, and animal life. However, a comprehensive assessment of this diversity is still lacking, particularly with regard to invertebrate soil fauna. In this study, we sampled soil beneath cushion plants in various climatic and geological conditions throughout the French Alps. Our results demonstrate that cushion plants host a remarkably high abundance and diversity of invertebrates, with some individual cushions hosting nearly 400 specimens belonging to 15 different families. Across all samples, 8845 specimens were found. The taxonomic diversity is particularly notable, with groups such as Collembola, Acari, and Nematoda, as well as Gastropoda, Diptera, Coleoptera, Hymenoptera, and Hemiptera. In total, 44 different families were identified. In particular, our findings show that cushion plants not only function as habitats for adult invertebrates, but also as site for the egg laying and larval development of several insect groups, including Diptera, Hemiptera, and Lepidoptera. In addition, different species of cushion plant tend to host distinct invertebrate communities, which makes them a key driver spatial variation in invertebrate populations. However, the factors determining the alpha diversity of invertebrates assemblages in nival environments remain unclear. Overall, our results emphasize the key role of cushion plants in maintaining biodiversity in the nival vegetation belt.

The European Alps were heavily glaciated during the Pleistocene, prompting debates about plants’ glacial refugia. While most alpine vegetation likely survived in lower mountain ranges, adjacent or disconnected from the Alps, or elsewhere in European lowlands, a century-old hypothesis suggests that some plants persisted on rocky peaks protruding from ice-covered areas. However, this so-called “nunatak” hypothesis has received relatively limited attention and support from phylogeographic studies. We modeled the potential distribution of 69 nival plant species during the Last Glacial Maximum (LGM, circa 20 to 25 ky ago) using species distribution models based on paleo-climatic conditions, paleo-ice extent, topographic metrics and bedrock lithologies. Two thirds of studied species and the majority of silicicolous species were predicted to have predominantly occurred on nunataks during the LGM in comparison to peripheral mountains or lowlands. Bedrock affinity, alongside topographic and climatic preferences, profoundly influenced predictions of species’ refugia locations and range contractions. Silicicolous species relied heavily on nunataks, where lithology and topographic ruggedness jointly favored their survival. Calcicolous species, in contrast, primarily found refugia in peripheral and extra-alpine massifs, the inner Alps being largely uninhabitable—either due to the extensive ice cover on calcareous massifs, often located at lower elevations, or because unglaciated ones were too unsuitable for their persistence. Generalist species, with broader ecological flexibility, persisted across more diverse refugia, favoring mainly the less harsh peripheral regions. Multivariate analyses identified seven cooccurring species groups associated with distinct potential refugia. Our findings challenge the view that nunatak refugia were undervalued during glacial periods, highlighting their significance for siliceous rock-specialist nival species. This work provides a well-delimited framework for further research on alpine paleobiogeography.

The alpine clematis (Clematis alpina L., Ranunculaceae) is a liana growing in mountain regions of northern Eurasia. In the European Alpine region, where the subspecies C. alpina subsp. alpina occurs, a few populations are isolated from the main range in the peripheral north-western Prealps, a relatively understudied but biogeographically important region. It has been shown that such edge populations could potentially contain a source of unique genetic variability that reflects past biogeographical and microevolutionary processes. We tested this hypothesis using sequence capture data and a large population sampling across the species range. We show that individuals from the north-western Prealps form a genetic cluster that is clearly distinct from the other individuals of the European subspecies C. alpina subsp. alpina. This cluster adds to two other geographically driven clusters with a larger spatial extent, that include populations from the rest of the Alps and from the Carpathians/Balkan Peninsula mountains, respectively. Genetic diversity indices such as inbreeding and nucleotide diversity are the highest and lowest, respectively, for the Prealps populations indicating a possible loss of diversity. Our results demonstrate the biogeographical importance of isolated, marginal populations as sources of distinctive lineages, and highlight the conservation value of the north-western Prealps populations of alpine clematis. They also point out the promising use of sequence capture of gene selected for studies at high phylogenetic level for studies at intraspecific level.