Réf. Pauli & al. 2007 - A

Référence bibliographique complète

PAULI, H., GOTTFRIED, M., REITER, K., KLETTNER, C., GRABHERR, G. 2007. Signals of range expansions and contractions of vascular plants in the high Alps: observations (1994–2004) at the GLORIA master site Schrankogel, Tyrol, Austria. Global Change Biology, 13, 147–156. [PDF]

Abstract: High mountain ecosystems are defined by low temperatures and are therefore considered to react sensitively to climate warming. Responding to observed changes in plant species richness on high peaks of the European Alps, an extensive setup of 1 m × 1 m permanent plots was established at the alpine-nival ecotone (between 2900 and 3450 m) on Mount Schrankogel, a GLORIA master site in the central Tyrolean Alps, Austria, in 1994. Recording was repeated in a representative selection of 362 quadrats in 2004. Ten years after the first recording, we observed an average change in vascular plant species richness from 11.4 to 12.7 species per plot, an increase of 11.8% (or of at least 10.6% at a 95% confidence level). The increase in species richness involved 23 species (about 43% of all taxa found at the ecotone), comprising both alpine and nival species and was pronouncedly higher in plots with subnival/nival vegetation than in plots with alpine grassland vegetation. Only three species showed a decrease in plot occupancy: one was an annual species, one was rare, and one a common nival plant that decreased in one part of the area but increased in the uppermost part. Species cover changed in relation to altitudinal preferences of species, showing significant declines of all subnival to nival plants, whereas alpine pioneer species increased in cover. Recent climate warming in the Alps, which has been twice as high as the global average, is considered to be the primary driver of the observed differential changes in species cover. Our results indicate an ongoing range contraction of subnival to nival species at their rear (i.e. lower) edge and a concurrent expansion of alpine pioneer species at their leading edge. Although this was expected from predictive distribution models and different temperature-related habitat preferences of alpine and nival species, we provide first evidence on – most likely – warming-induced species declines in the high European Alps. The projected acceleration of climate warming raises concerns that this phenomenon could become the major threat to biodiversity in high mountains.

Mots-clés

Alpine-nival ecotone - Climate warming - High mountain plants - Long-term monitoring - Migration - Peripheral populations - Plant diversity - Species decline - Species richness - Vegetation change

 

Organismes / Contact

• Department of Conservation Biology, Vegetation and Landscape Ecology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria

GLORIA: Global Observation Research Initiative in Alpine Environments (http://www.gloria.ac.at)

 

(1) - Paramètre(s) atmosphérique(s) modifié(s)

(2) - Elément(s) du milieu impacté(s)

(3) - Type(s) d'aléa impacté(s)

(3) - Sous-type(s) d'aléa

 

Vascular plant species richness at the alpine-nival ecotone

 

 

 

Pays / Zone

Massif / Secteur

Site(s) d'étude

Exposition

Altitude

Période(s) d'observation

Austria

Central Tyrolean Alps

Mount Schrankogel (a GLORIA master site)

 

2900 - 3450 m

1994-2004

 

(1) - Modifications des paramètres atmosphériques

Reconstitutions

 

Observations

 

Modélisations

 

Hypothèses

 

 

Informations complémentaires (données utilisées, méthode, scénarios, etc.)

 

 

(2) - Effets du changement climatique sur le milieu naturel

Reconstitutions

 

Observations

The observed increase in species richness as well as the changes in species cover, (i.e. losses for subnival/nival species and gains for alpine specie), are seen to be primarily caused by the recent warming in the region. Our results are consistent with other observations of increased species richness, with experimental evidence showing changes in species composition, and with modelling studies predicting differential shifts in distribution ranges. Our data indicate ongoing declines of the most cold-adapted species, while plants centred at lower elevations are filling their habitat. [see details and references in the study]

Modélisations

 

Hypothèses

Our data indicate ongoing declines of the most cold-adapted species, while plants centred at lower elevations are filling their habitat. This process will likely continue even if temperature ceases to further increase, owing to delayed response patterns of slow-growing high mountain plants. Climate warming predictions for 2100, downscaled for the region (HadCM3, A1FI storyline), are in the upper range of the IPCC projections (1.5–5.8°C). Such a drastic acceleration of climate warming implies that climate change would become the major threat to biodiversity in the high mountain regions of the European Alps. [see details and references in the study]

 

Sensibilité du milieu à des paramètres climatiques

Informations complémentaires (données utilisées, méthode, scénarios, etc.)

 

 

 

(3) - Effets du changement climatique sur l'aléa

Reconstitutions

 

Observations

 

Modélisations

 

Hypothèses

 

 

Paramètre de l'aléa

Sensibilité des paramètres de l'aléa à des paramètres climatiques

Informations complémentaires (données utilisées, méthode, scénarios, etc.)

 

 

 

 

(4) - Remarques générales

 

 

(5) - Syntèses et préconisations

 

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