Alpine Botany最新文献

Occurrence of Festuca apennina De Not. (4 × Fape), F. pratensis Huds. (2 × Fp) and the triploid, sterile hybrid F. apennina × F. pratensis (3 × Fape × Fp) was studied in 12 regions of the Swiss Alps. In total, 1908 plants were sampled in elevational strata scaled by 50 m between 850 and 2000 m a.s.l., and accompanying vegetation was assessed for each sampling point. The hybrid 3 × Fape × Fp was more frequent and more dominant than both parental species around 1400 m, and had a wider elevational distribution than 2 × Fp and 4 × Fape, which were confined to lower and higher elevation, respectively. As evidenced by their preferred accompanying species, 2 × Fp colonizes dryer, nutrient poorer environments than 4 × Fape which clearly prefers wet and nutrient rich environments. On the contrary, 3 × Fape × Fp thrives similarly well in both environments. The ability to reach an important biomass proportion in a sward, and the wide environmental adaptation of 3 × Fape × Fp is favored by its capacity to strongly expand by rhizomes. A single genotype of 3 × Fape × Fp was found to colonize an entire field of 2.3 ha with a maximum distance between clonal plants of 304 m. It is concluded that 3 × Fape × Fp is a potentially valuable pasture plant for use at higher altitudes, but it may reduce biodiversity via suppressing less competitive plant species.

Climate warming in mountain areas is increasing faster than the global average, threatening alpine plants. Climate affects many traits including seeds, the longevity of which is important for conservation, facilitating genebank storage. Seeds of alpine species are considered short-lived in storage, but their longevity increases when produced under a warmer parental environment. Consequently, with climate warming, seeds of alpine species may have increased fitness and be longer-lived in genebank storage. We assessed seed longevity under artificial ageing in 10 accessions of the arctic-alpine species Viscaria alpina stored under genebank conditions for different time periods over the last 20 years. The seed collection site was in the northern Apennines, where above average warming and variable precipitation has been recorded. The time taken for viability to fall to 50% (p₅₀) was estimated using probit analysis; correlation and general linear regression were used to investigate the effects of length of time in storage, seed mass and climate under which seeds were produced on seed longevity. p₅₀ varied between 7.77 and 18.49 days. There was no relationship between length of time in storage or seed mass on seed longevity. p₅₀ was higher in years with increased temperature and lower precipitation during the growing season, with precipitation having more impact than temperature. The results suggest that seeds of alpine species are suitable for genebank storage, and inter-annual variation in precipitation induces a plastic response in seed longevity. Using genebank stored seeds provides insights into how alpine species may respond to future climate changes and could have implications for genebank storage.

The species-richness of the flora in the European Alps results from complex interactions between geographical, climatic and environmental factors. In this study, we focus on a complex of closely related Alpine plants: Primula hirsuta, P. pedemontana and their relatives. Using a large DNA dataset of thousands of single-nucleotide polymorphisms sequenced across 149 individuals spanning all the western Alps, we refine phylogenetic relationships in this clade and explore the evolutionary origins of a mysterious lineage found in one valley of the Écrins range (France): the Valgaudemar. In particular, we demonstrate that this lineage did not originate from a simple allopatric divergence, but from an isolated lineage related to Primula pedemontana, which later got introgressed by P. hirsuta. This leads us to develop a phylogeographic scenario explaining the origins of the Valgaudemar lineage, and shed light on a potential glacial refugium in the south of the Écrins range. We believe this study takes part in the deep understanding of the origins of endemism in the European Alps and more generally of the maintaining of species diversity.

With ongoing climate change and increasing human activities, shrub expansion has been observed worldwide. Alpine meadows are one of the ecosystem types that are sensitive to shrub expansion. This study aimed to investigate the effects of an actinorhizal shrub species on nitrogen (N) status of the soil and other plants in the alpine meadow ecosystem. We measured the ¹⁵N natural abundance and N concentration of different tissues of Hippophae tibetana, and examined its effects on the ¹⁵N natural abundance and N content of the soil and neighboring plants at different locations surrounding the shrub clumps in an alpine meadow in the Qinghai-Tibet Plateau. The results show that the δ¹⁵N in branches and roots of H. tibetana was much lower, and N concentration much higher, than that of other plants. δ¹⁵N of the plants and soil surrounding the shrub clumps was not significantly altered. Underneath the shrub canopy, due to the N-rich leaf litter of H. tibetana, N content of neighboring plants significantly increased compared to plants at other locations. However, the aboveground biomass of neighboring plants was marginally lower underneath the canopy than outside. These results suggest a minor N-facilitation effect of this actinorhizal shrub on the soil and neighboring plants through its N-rich leaf litter. However, the facilitation effect was not enough to offset the negative effect of the shrub on its neighboring plants due to competition of other resources.

The dwarf bulrush (Typha minima Hoppe) is a perennial aquatic plant that has been rapidly disappearing in Northern Europe following flood control methods (dikes, dams, embankments). Floods, by erasing and creating new banks, maintain a metapopulation system (extinction/recolonization of populations). The largest and most diverse populations are located in France. To identify the size of the metapopulations, we studied clonality, genetic diversity and genetic structure of an extensive sample of the French populations using AFLP markers. Clonality was high (on average, each genotype was found in three copies) but variable across sites: some genotypes had a high number of copies (> 20) and were distributed over several river catchments while 239 genotypes were unique. Genetic diversity was high but did not accumulate downstream indicating both up- and downstream long-distance gene flow through pollen and seeds. Genetic diversity is structured in three major clusters. One (cluster N) is restricted to sites north of 44°4 N. The other two (clusters S and E), coexist in river catchments or even in the same site. However, the highest F_st were found between cluster E and clusters N or S, indicating a recolonization from different refugia, one possibly located east of the Alps (cluster E) and one or two on the Western side. Therefore conservation actions should take into account these three major conservation units (CU) in France. These CU cover large areas. It is thus important to maintain a natural river dynamics with frequent extinction/recolonization events over whole drainage basins.

Mesoscale heterogeneity of alpine landscapes generates snowmelt gradients resulting in a distinct vegetation zonation from almost snow-free fellfields to long-lasting snowbeds. Although the vegetative trait variation along such gradients has been intensively studied, little is known about whether and how seed germination is adapted to the variable snowpack duration. Here, we compare the seed germination niches of 18 characteristic plant species occurring in four distinct plant communities (alpine lichen heath—Festuca varia grassland—Geranium-Hedysarum meadow—snowbed) along an alpine snowmelt gradient in the North Caucasus (Russia). In a fully factorial experiment, we tested seed germination responses to temperature (10/2, 14/6, 18/10, 22/14, 26/18 and 30/22 °C) and water potential (0, − 0.2, − 0.4, − 0.6 and − 0.8 MPa) gradients, reflecting the full spectrum of seedling establishment conditions in the study system. Community-specific germination niches were identified by generalised mixed model with Bayesian estimation. Our study revealed that the species from the four focal communities significantly differed in their temperature requirements for germination, whereas soil moisture was found to be a limiting factor for seedling establishment along the entire gradient. The snowbed germination was constrained to comparatively high temperatures above 10 °C, whereas seed germination in alpine lichen heaths occurred under a wide range of experimental conditions. The seed germination patterns of species from Festuca varia grasslands and Geranium-Hedysarum meadows reflected their intermediate position along the snowmelt gradient. We conclude that seed germination niche is affected by the environmental filtering along the snowmelt gradient thus departing from the general alpine germination syndrome.

The inner-alpine dry valleys of the Swiss Alps are characterized by subcontinental climate, leading to many peculiarities in dry grassland species composition. Despite their well-known uniqueness, comprehensive studies on biodiversity patterns of the dry grasslands in these valleys were still missing. To close this gap, we sampled 161 10-m² vegetation plots in the Rhône, Rhine and Inn valleys, recording vascular plants, terricolous bryophyte and lichen species, as well as environmental data. Additionally, we tested the scale-dependence of environmental drivers using 34 nested-plot series with seven grain sizes (0.0001–100 m²). We analysed the effects of environmental drivers related to productivity/stress, disturbance and within-plot heterogeneity on species richness. Mean species richness ranged from 2.3 species in 0.0001 m² to 58.8 species in 100 m². For all taxa combined, the most relevant drivers at the grain size of 10 m² were southing (negative), litter (negative), mean annual precipitation (unimodal), gravel cover (negative), inclination (unimodal) and mean annual precipitation (unimodal). For vascular plants the pattern was similar, while bryophyte and lichen richness differed by the opposite relationship to mean annual precipitation as well as negative influences of mean herb layer height, grazing and mowing. The explained variance of the multiple regression model increased with grain size, with very low values for the smallest two grain sizes. While southing and litter had high importance for the fiver larger grain sizes, pH and gravel cover were particularly important at the intermediate grain sizes, and inclination and mean annual precipitation for the two largest grain sizes. The findings emphasize the importance of taxonomic group and grain size for patterns and drivers of species richness in vegetation, consistent with ecological theory. Differences in the diversity–environment relationships among the three taxonomic groups can partly be explained by asymmetric competition that leads to low bryophyte and lichen diversity where vascular plants do well and vice versa. The relatively low alpha diversity of vascular plants in dry grasslands in Swiss inner-alpine valleys compared to similar communities in other parts of the Palaearctic remains puzzling, especially because Swiss stands are often large and well-preserved.

Refugia will be important to the response of alpine vegetation to climate change. Potential refugia exist at multiple scales, including a range-wide mesoscale. The climates of alpine grasslands of 23 mountain ranges of southern and central Europe were evaluated to assess whether each range would support potential refugia in projected future climates. The mean temperature the warmest month and quarter with the precipitation of the warmest quarter, derived from gridded global climate data at ~ 1 km resolution, were examined range-wide and for areas identified as alpine grassland to identify limits within each range. The overlap of current grassland climate and future range-wide climates, the latter calculated using regional projections from three global models with three socioeconomic driving scenarios, were assessed as potential refugia. Among the nine projections, three had none of the current grassland climates in any of the 23 ranges by 2100, while two retained more than 20% in more than half of the ranges. Most of the potential mesoscale refugia were in the Alps. Micro-refugia and warmer and drier fundamental climatic niches for alpine grassland species could mitigate these bleak results, but otherwise they are extremely threatened.

Early plant primary succession in recently deglacierized terrains is a good indicator of the species losses and gains that affect novel alpine plant communities migrating under the pressure of climate warming. In the tropical alpine -páramo- region of the northern Andes, home to the world's greatest alpine phyto-diversity, forced primary succession will condition the conservation of many species. Using a post-glacial chronosequence between the little ice age and present below the Conejeras glacier (Colombia) as a space-for-time substitution approach, we sought to determine how time since deglacierization affects the composition, the biogeographic origin and the growth form distribution of novel tropical alpine plant communities. Using an array of multivariate techniques and the Dirichlet model, we assessed relationships among plant communities and with environmental factors. Communities established in less than 169 years lacked a number of characteristic and endemic species usually found in the national park Los Nevados, such as Calamagrostis effusa, Senecio isabelis and Espeletia hartwegiana. Moreover, these communities have been colonized by non-native species, e.g., Rumex acetosella. Upright shrubs and large tussock grasses, characteristic of the alpine tropics, established slowly because they required highly organic, slow-developing soils. Taxa of tropical biogeographic origin were under-represented early after deglacierization in comparison with temperate taxa. These results suggest the existence of a strong climatic debt for some native species, tropical growth forms and taxa of tropical origin, which may translate into significant taxonomic and functional losses whereas the few observed gains concern the establishment of non-native species.

Pollination-induced flower senescence is expected in species of dry habitats with large long-lived water-demanding flowers as means for reducing floral maintenance costs. We investigated this hypothesis in Alstroemeria umbellata, an alpine species of the semiarid central Chilean Andes. Pollinator-excluded flowers were submitted to hand cross-pollination and manual pollen removal and monitored twice daily to assess the time spans of four floral stages and two expressions of flower longevity. Wilting and floral stage duration responses in open-pollinated flowers were studied. Ramet-level floral and leaf water content were quantified. Pollen removal had no effect on any floral trait analyzed. Hand cross-pollination reduced the functional flower lifespan from 7.5 to 6.7 days and the female stage from 3.4 to 1.6 days, but did not have a clear effect on the total flower lifespan (9.3 days). Counterintuitively, the length of the dehydration stage increased following pollination. No effect of pollination was detected in naturally pollinated flowers. Inflorescences contained > 3.5 g of water, > 3 times more than the ramet leaves, with > 50% of floral water housed in the turgid tepals. Although inflorescences contain much more water than the leaves, based on the open-pollination results, the amount of tepal water saved through pollination-associated floral senescence under natural circumstances is likely to be far less than the ~ 11% predicted by the manipulative experiment. Knowledge of tepal and leaf transpiration rates and the water content of underground plant parts is desirable to arrive at a more precise assessment of the impact of pollination-associated floral senescence on the water balance in A. umbellata.