The rich sides of mountain summits – a pan-European view on aspect preferences of alpine plants

Manuela Winkler (1) , Andrea Lamprecht (1) , Klaus Steinbauer (1) , Karl Hülber (2, 3) , Jean-Paul Theurillat (4, 5) , Frank Breiner (6, 7) , Philippe Choler (8, 9) , Siegrun Ertl (2) , Alba Gutiérrez Girón (10) , Graziano Rossi (11) , Pascal Vittoz (12) , Maia Akhalkatsi (13) , Christian Bay (14) , José-Luis Benito Alonso (15) , Tomas Bergström (16) , Maria Laura Carranza (17) , Emmanuel Corcket (18) , Jan Dick (19) , Brigitta Erschbamer (20) , Rosa Fernández Calzado (21) , Anna Maria Fosaa (22) , Rosario G. Gavilán (10) , Dany Ghosn (23) , Khatuna Gigauri (13) , Doris Huber (24) , Róbert Kanka (25) , George Kazakis (23) , Martin Klipp (26) , Jozef Kollár (25) , Thomas Kudernatsch (27) , Per Larsson (28) , Martin Mallaun (20) , Ottar Michelsen (29) , Pavel Moiseev (30) , Dmitry Moiseev (30) , Ulf Molau (28) , Joaquín Molero Mesa (21) , Umberto Morra Di Cella (31) , Laszlo Nagy (32) , Martina Petey (31) , Mihai Pușcaș (33) , Christian Rixen (6) , Angela Stanisci (17) , Michael Suen (2) , Anne O. Syverhuset (34) , Marcello Tomaselli (35) , Peter Unterluggauer (20) , Tudor Ursu (36) , Luis Villar (15) , Michael Gottfried (1) , Harald Pauli (1)

1 BOKU - Universität für Bodenkultur Wien = University of Natural Resources and Life [Vienne, Autriche]
2 Department of Botany and Biodiversity Research
3 VINCA - Vienna Institute for Nature Conservation and Analyses
4 CAP - Centre alpien de Phytogéographie
5 UNIGE - Université de Genève = University of Geneva
6 Swiss Federal Institute for Forest, Snow and Landscape Research WSL
7 Department of Ecology and Evolution
8 Université de Grenoble
9 LTER Zone Atelier Alpes
10 UCM - Universidad Complutense de Madrid = Complutense University of Madrid [Madrid]
11 Department of Earth and Environmental Sciences
12 Institute of Earth Surface Dynamics
13 Ilia State University [Tbilisi]
14 Aarhus University [Aarhus]
15 IPE - CSIC - Instituto Pirenaico de Ecologìa = Pyrenean Institute of Ecology [Zaragoza]
16 County Administrative Board of Jämtlands län
17 UNIMOL - Università degli Studi del Molise = University of Molise
18 BioGeCo - Biodiversité, Gènes & Communautés
19 NERC - Natural Environment Research Council
20 Institute of Botany
21 UGR - Universidad de Granada = University of Granada
22 Faroese Museum of Natural History
23 CIHEAM-IAMC - Centre International de Hautes Etudes Agronomiques Méditerranéennes - Institut Agronomique Méditerranéen de Chania
24 National Park of Berchtesgaden
25 Institute of Landscape Ecology
26 Referat Naturschutz
27 Nordwestdeutsche Forstliche Versuchsanstalt
28 GU - Göteborgs Universitet = University of Gothenburg
29 NTNU - Norwegian University of Science and Technology
30 Institute of Plant and Animal Ecology
31 ARPA VDA - Agenzia Regionale per la Protezione dell'Ambiente Valle D'Aosta
32 Departamento de Biologia Vegetal, Instituto de Biologia
33 A. Borza Botanical Garden
34 NINA - Norwegian Institute for Nature Research
35 UNIPR - Università degli studi di Parma = University of Parma
36 NIRBDS - National Institute of Research and Development for Biological Sciences

Aim In the alpine life zone, plant diversity is strongly determined by local topography and microclimate. We assessed the extent to which aspect and its relatedness to temperature affect plant species diversity, and the colonization and disappearance of species on alpine summits on a pan-European scale. Location Mountain summits in Europe's alpine life zone. Methods Vascular plant species and their percentage cover were recorded in permanent plots in each cardinal direction on 123 summits in 32 regions across Europe. For a subset from 17 regions, resurvey data and 6-year soil temperature series were available. Differences in temperature sum and Shannon index as well as species richness, colonization and disappearance of species among cardinal directions were analysed using linear mixed-effects and generalised mixed-effects models, respectively. Results Temperature sums were higher in east- and south-facing aspects than in the north-facing ones, while the west-facing ones were intermediate; differences were smallest in northern Europe. The patterns of temperature sums among aspects were consistent among years. In temperate regions, thermal differences were reflected by plant diversity, whereas this relationship was weaker or absent on Mediterranean and boreal mountains. Colonization of species was positively related to temperature on Mediterranean and temperate mountains, whereas disappearance of species was not related to temperature. Main conclusions Thermal differences caused by solar radiation determine plant species diversity on temperate mountains. Advantages for plants on eastern slopes may result from the combined effects of a longer diurnal period of radiation due to convection cloud effects in the afternoon and the sheltered position against the prevailing westerly winds. In northern Europe, long summer days and low sun angles can even out differences among aspects. On Mediterranean summits, summer drought may limit species numbers on the warmer slopes. Warmer aspects support a higher number of colonization events. Hence, aspect can be a principal determinant of the pace of climate-induced migration processes.

Mots clés: alpine life zone; climate change; GLORIA; long-term monitoring; slope aspect; species diversity

Mots clés: Europe; soil temperature; vascular plants

Domaines: Sciences du Vivant [q-bio]

Manuela Winkler, Andrea Lamprecht, Klaus Steinbauer, Karl Hülber, Jean-Paul Theurillat, et al.. The rich sides of mountain summits – a pan-European view on aspect preferences of alpine plants. Journal of Biogeography, 2016, 43 (11), pp.2261-2273. ⟨10.1111/jbi.12835⟩. ⟨hal-02637180⟩