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Campos de altitude are high-altitude grasslands found in the mountain ranges of southeastern and southern Brazil, which are characterized by high species richness and endemism. Because of the difficulty in delimiting this vegetation type, measuring biodiversity patterns is challenging. Here, we compared the application of two methods using spatial data to estimate angiosperm diversity in campos de altitude: (1) filtering occurrence data by elevation, canopy height, location and keywords and; (2) the same as the first, however, adding a filter of "campos de altitude" in the vegetation type of the Flora e Funga do Brasil database. Also, we discuss conservation status, plant collections, endemism, vegetation data and similarity among 14 sites harboring campos de altitude. Our two resulting lists indicated between 1087 and 2398 angiosperm species and infraspecific taxa in campos de altitude, mostly belonging to Asteraceae and Poaceae and endemic to Brazil. Extrapolations of species richness suggest a potential number of up to 4000 species. Of the taxa assessed for conservation status, 53–65% are threatened or near threatened. The flora of campos de altitude is more similar on closely located mountains rather than on mountains with similar geological characteristics and origin. We provide an editable list online destined to seek help from taxonomists to generate a more accurate species list, to support advances in knowledge on this unique tropical montane ecosystem. [ABSTRACT FROM AUTHOR]

While the high elevation limit of trees is commonly related to low temperature, the rear edge of their distribution is often associated with drought. Here we explore phenology traits that contribute to a mechanistic explanation of both these edges of the fundamental niche in the broad leaved evergreen Quercus pannosa s.l. Populations of this species reach a drought limit (DL) at 2510 m in the semi-arid upper Yangtze valley, and a cold limit (CL) at 4270 m, very close to the conifer treeline, within a short geographical distance. Trees reach a height of only 4–7 m at both climatic limits, and > 30 m height at optimum site (OS) at 3440 m. At OS, flushing starts in mid-May and at the summer solstice at CL (after late frosts end), suggesting a photoperiod control. At DL, oak phenology tracks the (irregular) arrival of the monsoon. Shoots and leaves grew fastest and for the shortest period at DL, and slowest at CL, in both cases forming 4–7 cm long new shoots per year, contrasted by 12–13 cm a−1 at OS. Maturation of leaves (length and specific leaf area, SLA) was again fastest at DL, followed by CL and slowest at OS, with a much longer shoot growth duration per year and bigger leaves. We conclude that the period favorable for growth and maturation was more than halved at both range limits (by frost or drought) compared to the optimum site, pointing at a common range restriction by the duration of the growing season. [ABSTRACT FROM AUTHOR]

Abandonment of pastures and successional shrub expansion are widespread in European mountain regions. Moderate shrub encroachment is perceived beneficial for plant diversity by adding new species without outcompeting existing ones, yet systematic evidence is missing. We surveyed vegetation along 24 transects from open pasture into shrubland across the Swiss Alps using a new protocol distinguishing different spatial scales, shrub cover of each plot (2 × 2 m) and larger-scale zonal cover along the transect. Data were analysed using generalized linear models of shrub cover, shrub species and environmental conditions, such as geology, aspect or soil. Most shrub communities were dominated by Alnus viridis (62% of transects) and Pinus mugo (25%), and the rest by other shrub species (13%). These dominant shrub species explained vegetation response to shrub cover well, without need of environmental variables in the model. Compared to open pasture, A. viridis resulted in an immediate linear decline in plant species richness and a marginal increase in beta-diversity (maximally + 10% at 35% cover). Dense A. viridis hosted 62% less species than open pasture. In P. mugo, species richness remained stable until 40% shrub cover and dropped thereafter; beta-diversity peaked at 35% cover. Hence, scattered P. mugo increases beta-diversity without impairing species richness. In transects dominated by other shrubs, species richness and beta-diversity peaked at 40–60% shrub cover (+ 23% both). A. viridis reduced species richness in a larger area around the shrubs than P. mugo. Therefore, effects of shrub encroachment on plant diversity cannot be generalized and depend on dominant shrub species. [ABSTRACT FROM AUTHOR]

Recent years have seen a surge of interest in understanding patterns and processes of plant invasions into mountains. Here, we synthesise current knowledge about the spread of non-native plants along elevation gradients, emphasising the current status and impacts that these species have in alpine ecosystems. Globally, invasions along elevation gradients are influenced by propagule availability, environmental constraints on population growth, evolutionary change and biotic interactions. The highest elevations are so far relatively free from non-native plants. Nonetheless, in total nearly 200 non-native plant species have been recorded from alpine environments around the world. However, we identified only three species as specifically cold-adapted, with the overwhelming majority having their centres of distribution under warmer environments, and few have substantial impacts on native communities. A combination of low propagule availability and low invasibility likely explain why alpine environments host few non-native plants relative to lowland ecosystems. However, experiences in some areas demonstrate that alpine ecosystems are not inherently resistant to invasions. Furthermore, they will face increasing pressure from the introduction of pre-adapted species, climate change, and the range expansion of native species, which are already causing concern in some areas. Nonetheless, because they are still relatively free from non-native plants, preventative action could be an effective way to limit future impacts of invasions in alpine environments. [ABSTRACT FROM AUTHOR]

Stable carbon and nitrogen isotopes provide time-integrated signals of plant carbon and nitrogen relations. We assessed an entire alpine flora in the Swiss Alps at ca. 2400 m elevation, using year 2007 herbarium samples of 245 species, 141 genera and 42 families to explore functional trait diversity. Despite overall similar macro-environmental conditions (moisture, soils, elevation), signal variation covered the full spectrum known for C plants. Variation among means for plant families for both δC and δN was smaller than variation among species within families. Species identity was of far greater importance than family affiliation. Similarly, tissue nitrogen and carbon concentrations varied in a rather species-specific manner, not permitting any a priori plant functional group definition based on such traits. The study also yielded tissue-type specificity of isotope signals. The elevation signal in δC (known to be less negative at high elevation) was much less pronounced than observed previously in con-generic comparisons. Thus, elevational δC trends are hard to distinguish from species effects in mixed populations over narrow ranges of elevation. δN data offer more space for ecological interpretation and show family specificity of signals in few cases. Cyperaceae, the most prominent family in this region, show no discrimination against N (like Fabaceae) and must have access to N sources different from most other families. This deserves experimental clarification, given the significance of Cyperaceae in cold environments. Overall, our study evidenced very high functional diversity among alpine plant species, as captured by these isotope signals. [ABSTRACT FROM AUTHOR]

Shrubs are an important component of mountain ecosystems in terms of productivity and diversity. The estimate of shrub biomass via allometric equations represents a non-destructive alternative to obtain quantitative data. We propose allometric equations to estimate aboveground biomass from easily acquirable descriptive parameters of plant height and cover using linear models for five of the most abundant subalpine shrub species in European mountain or boreal ecosystems: Rhododendron ferrugineum, Vaccinium myrtillus, V. uliginosum, V. vitis- idaea and Juniperus sibirica. Samples used for the establishment of the equations are from non-disturbed Pinus cembra- Larix decidua stands, and from adjacent stands frequently disturbed by snow avalanches. The equations adequately predict shrub biomass for all species except V. uliginosum. They thus provide a useful and non-destructive method for estimating aboveground shrub biomass in subalpine ecosystems. [ABSTRACT FROM AUTHOR]