Georg Grabherr

Recent Plant Diversity Changes on Europe’s Mountain Summits

Climb Every Mountain Mountaintop floras across Europe appear to be responding to climatic change in terms of upslope species range shifts. Pauli et al. (p. 353) systematically analyzed data gathered from standardized permanent plots on 66 high-mountain environments across Europe. On average, mountaintop species numbers have increased significantly during the last decade. However, this increase is a net effect of gains and losses, with losses particularly affecting mountains of Mediterranean regions and their endemic species. This turnover is largely consistent with model predictions and indicates that high-altitude species, and in particular the rich endemic alpine flora of many Mediterranean mountain ranges, will come under increasing pressure in the predicted warmer and drier climates in this region. European mountaintop flower species richness is increasing on northern summits but decreasing on southern summits. In mountainous regions, climate warming is expected to shift species’ ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe’s major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras’ species richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (–1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region.

Biological and physical signs of climate change: focus on mosquito-borne diseases

The Intergovernmental Panel on Climate Change concluded that there is “discernible evidence” that humans—through accelerating changes in multiple forcing factors—have begun to alter the earths climate regime. Such conclusions are based primarily upon so-called “fingerprint” studies, namely the warming pattern in the midtroposphere in the Southern Hemisphere, the disproportionate rise in nighttime and winter temperatures, and the statistical increase in extreme weather events in many nations. All three aspects of climate change and climate variability have biological implications. Detection of climate change has also drawn upon data from glacial records that indicate a general retreat of tropical summit glaciers. Here the authors examine biological (plant and insect) data, glacial findings, and temperature records taken at high-elevation, mountainous regions. It is concluded that, at high elevations, the overall trends regarding glaciers, plants, insect range, and shifting isotherms show remarkable intern...

Landscape patch shape complexity as an effective measure for plant species richness in rural landscapes

The application of landscape patch shape complexity as a predictor ofvascularplant and bryophyte species richness is analysed. Several common complexityindices (shape index, fractal dimension, comparison to the area of the minimumbounding rectangle) are tested for their predictive power for plant speciesrichness. One new robust measure for shape complexity is presented whichovercomes some disadvantages of common complexity measures applied to highresolution analysis of agricultural landscapes based on aerial photographs. Thenew index is based on the number of shape characterising points along apolygon’s boundary. This new measure shows promising predictive capabilitiesforspecies richness of vascular plants and bryophytes (correlation coefficient:0.85 for vascular plants, 0.74 for bryophytes).

Surrogate taxa for biodiversity in agricultural landscapes of eastern Austria

In an agricultural landscape in eastern Austria eight terrestrial organism groups were investigated as potential biodiversity indicators. We present a cross-taxon congruence assessment obtained at the landscape scale using two groups of plants (bryophytes and vascular plants), five groups of invertebrates (gastropods, spiders, orthopterans, carabid beetles and ants) and one vertebrate taxon (birds). We tested four different approaches: correlated species counts, surrogate measures of the overall species richness that was assessed, a multi-taxa (or shopping basket) approach and a simple complementarity algorithm. With few exceptions, pairwise correlations between taxa, correlations between one taxon and the species richness of the remaining groups, and correlations between a combination of the richness of two taxa and the remaining species richness were highly positive. Complementarity-derived priority sets of sampling sites using one taxon as a surrogate for the pooled species richness of all other taxa captured significantly more species than selecting areas randomly. As an essential first step in selecting useful biodiversity indicators, we demonstrate that species richness of vascular plants and birds showed the highest correlations with the overall species richness. In a multi-taxa approach and in complementarity site selection, each of the eight investigated taxa had the capability to capture a high percentage of the overall species richness.

Patterns and Current Changes in Alpine Plant Diversity

Global warming, resulting from increased concentrations of greenhouse gases, may affect ecosystems in different ways and to various extents (Emanuel et al. 1985; Bolin et al. 1986; Solomon and Shugart 1993, etc.). Coral reefs, mangroves, the arctic tundra, and high mountain ecosystems are particularly vulnerable (Markham et al. 1993).

Prediction of Vegetation Patterns at the Limits of Plant Life: A New View of the Alpine-Nival Ecotone

The distribution pattern of individual plant species, as well as of plant communities, at the transition between the alpine and the nival environment (= alpine-nival ecotone) is likely to be drasti...

A resampling approach for evaluating effects of pasture abandonment on subalpine plant species diversity

Abstract The decline of species-rich semi-natural calcareous grasslands is a major conservation problem throughout Europe. Maintenance of traditional animal husbandry is often recommended as an important management strategy. However, results that underpin such management recommendations were derived predominantly from lowland studies and may not be easily applicable to high mountain areas. In this study we analyse the importance of traditional low-intensity summer farming (cattle grazing) for vascular plant species diversity of a subalpine region in the northern calcareous Alps in Austria by resampling from an existing dataset on its vegetation. Results indicate a significant long term decline of plant species diversity following abandonment at the landscape scale. In contrast, within-community effects of pasture abandonment on plant species diversity are equivocal and strongly depend on the plant community. We suppose these differences to be due to diet preferences of cattle as well as to the differential importance of competition for structuring the respective communities. From our results we infer that the main mechanism by which pasture abandonment affects vascular plant species diversity, at least during the first ca. 100 yr documented here, are not local-scale competitive exclusion processes within persisting communities. Instead, post-abandonment successional community displacements that cause a landscape scale homogenization of the vegetation cover seem to be primarily responsible for a decline of species diversity. We conclude, that successful management of vascular plant species diversity in subalpine regions of the Northeastern Calcareous Alps will depend on the maintenance of large scale pasture systems with a spatially variable disturbance regime. Nomenclature: Adler et al. (1994). Abbreviations: DEM = Digital Elevation Model; GIS = Geographical Information System; WET = Topographic Wetness Index; EROS = Topographic Erosion Index; GLM = Generalized Linear Model; S = Species Richness; H = Shannon Index of diversity; E = Evenness; CC = Number of plant communities; dC = Berger-Parker Index of community diversity.

Phenological Responses of Snowbed Species to Snow Removal Dates in the Central Alps: Implications for Climate Warming

Abstract Low temperatures and the short growing season in high altitude snow patches in temperate mountains constrain life cycles and reproduction of snowbed species. This leads to a highly adapted timing of sexual reproduction. Winter precipitation and temperature, the main factors determining growing season length, are predicted to change with global warming. To understand their impacts on plant phenology, we studied the responses of seven alpine vascular plant species during 2001. Temperature had a clear impact on phenological patterns. The start of the reproductive development was not directly linked with the date of snowmelt, but rather with the cumulative energy input. In addition, photoperiodism may also contribute to the control of plant development through an increasing temporal adjustment of phenology until flowering.

Assessing the Long-Term Dynamics of Endemic Plants at Summit Habitats

Evidence from high summits in the Alps, that mountain plants have migrated upwards (Gottfried et al. 1994;Grabherr et al. 1994, 2001; Pauli et al. 1996), prompted the initiation of a Global Observation Network (GLORIA, see http://www.gloria.ac.at) to study climate change induced effects on alpine biodiversity (Grabherr et al. 2000; Pauli et al. 2001). Mountain tops or summits form comparable environmental units, where habitats of every exposure (N, E, S, and W) are present within a small area and are little affected by shading from neighbouring land features. Mountain summits often have a high habitat diversity. They are of particular interest for detecting any upward migration of species. The summits are prominent landmarks that can be readily relocated for re-investigations and the highest summit points can be characterised by an average climate at any given altitude.

Long-Term Monitoring of Mountain Peaks in The Alps

Historical records of nival summit floras from the Alps were compared with the recent species composition at the same summits revisited in the years 1992/1993. A general trend to increased species richness could be detected. For one particular summit, Piz Linard, quantitative data were provided by the historical author; our revisitation showed clearly that species abundance has increased substantially at this mountain during the last 50 years. The increase in species richness as well as the increase in abundance suggest that the observed warming of 1 – 2°C since the turn of the century has affected the biota at these low-temperature limits of plant life. This is in agreement with unexpected observations, such as the record of the uppermost population of Carex curvula at 3468 m. Carex curvula is the dominating species of the late successional grassland vegetation which occupies an altitudinal belt between 2400 – 2800 m. Furthermore, the uppermost storage of Swiss stone pine seeds (3103 m; seeds were germinating) was recorded. The seeds are distributed by the bird Nucifraga caryocatactes that stores them in clusters at places which are less snow-covered in winter time. In this case the bird brought the seeds from the timber line more than 700 meters below up to the discovered storage-place. These observations prove an upward migration of alpine biota.