Das Projekt "Environmental Changes at the Ecocline between Subalpine and Alpine Vegetation Belts: Reaction of the Vegetation Cover^Changements environnementaux et modification de l'ecocline subalpin-alpin: reaction de la couverture vegetale (FRA)" wird vom Umweltbundesamt gefördert und von Ville de Geneve, Departement municipal des affaires culturelles, Conservatoire et Jardin botaniques durchgeführt. What will be the rapidity of the answer of plants considering the mechanisms of inertia (buffer effect of phytocoenoses, competition, physiological plasticity)? - Will the response be correlated and be directly proportional to the observed climatic changes? - Will all the plant communities be modified simultaneously or will some of them perdure for some while? - Will the different parts of the plant communities (synusiae) react simultaneously or differentially? - How is the transformation of the ecocline going to happen (progressively, by salutation, catastrophically)? The aim of the project is to measure the qualitative and quantitative response of the vegetation to modifications in environmental parameters, especially climatic ones. The vegetation cover is studied at all levels of spatial organisation, from the synusia to complexes of phytocoenoses. Two transects about 2 km wide were delimited on siliceous rock in the Valais: Val d'Arpette, Orsieres (1700-2800 m) and Belalp, Naters (1900-2800 m). 230 phytocoenological releves and 1128 synusial releves were performed and 22 permanent plots were established. The distribution of the flora is analysed in altitudinal sections of 100 m. Presently, 298 species of vascular plants are known for Val d'Arpette and 339 for Belalp. Beside the flora and vegetation, the phenology of selected species (e.g. Arolla Pine, prostrated Mountain Pine, Green Alder, Rhododendron) is being also studied in relation to meso- and microclimate, especially temperature. 31 phenological permanent plots were established and 257 phenological releves were performed. Microclimatic measurements of temperature were performed with the Palmann method of sugar inversion (500 blades) and direct measurement with 3 data loggers Grant Squirrel. In order to assess the qualitative and quantitative impact of predicted climatic changes on alpine vegetation, the project intends to elaborate a predictive model, in collaboration with four other projects (soils, bryophytes, genetical polymorphism of selected species, and modeling of plant distribution) to evaluate the potential modifications on the vegetation at several levels of integration (synusiae, plant communities, landscape), and the rapidity of those modifications. In addition, a long-term monitoring of the vegetation is established. The study of the sub alpine/alpine ecocline is carried on at two separate transects (1700-2800 m; 1900-2900 m) on siliceous rocks in the Valais with vegetation types analyses, structural analyses of alpha-, beta-, altitudinal plant diversity, vegetation mapping, permanent plots. In addition, there are phenological observations and investigations on the reproductive biology of key species linked with micro- and mesoclimate measurements.
Das Projekt "Intraspecific Genetic Polymorphism of the Subalpine-Alpine Transition in the Perspective of Environmental Change^Le polymorphisme genetique intraspecifique dans l'ecocline subalpin-alpin: un indice revelateur des potentialites d'adaptation aux changements environnnementaux (FRA)" wird vom Umweltbundesamt gefördert und von Universite de Neuchatel, Institut de Botanique durchgeführt. Leading Questions: - Based on the genetic polymorphism, what are the evolutive potential of the species in the sub alpine-alpine ecotone? - Is there any correlation between the genetic structure of the species and its position along the altitudinal gradient, which could be used as a marker of climate change? - What is the influence of the life cycles (annual, short living perennial, long living perennial) and of the reproductive system (allo gamy, auto gamy, apomixis) on the genetic structure? Abstract: Genetic analyses are being performed on two altitudinal transects in Arpette and Belalp in order to test if the variation of some genetic markers correlates with altitude (space scale). Because temperature linearly decreases as a function of altitude, they could be used later as a monitor of the genetic response to climate change (time scale). Moreover, intraspecific genetic diversity is investigated in order to test if genetic diversity decreases at the altitudinal distribution limits of the species. Genetic diversity is a necessary condition of evolution and consequently of the potential of adaptation to environmental changes. Genetic studies on Anthoxanthum alpinum (alpine vernal grass), Larix decidua (larch) and Vaccinium myrtillus (blueberry) have started. Preliminary results on A. alpinum indicate that the frequency of one allozyme of the glutamate oxaloacetate transaminases increases with altitude at both sites. Moreover, genetic diversity tends to decrease at both ends of the distribution of that species. Complementary information: In the context of climate change, genetical markers correlated with altitude (temperature gradient) are investigated to find out those ones which could be used to follow a genetic response of species to climate change. Analyses of 'Anthoxynthum alpinum' are finished and data processing is in progress. In all, 18 subpopulations from two transects at Belalp and one transect at Val d'Arpette were studied for six enzyme systems on eleven loci. Three alleles GOT2C (glutamate oxaloacetate transaminase), MDH1B (malate dahydrogenase) and PX1A (peroxydase) show a correlation with elevation. These markers could be used to follow the effect of climate change on the genetic structure of the populations if their selective value is demonstrated (phase 2 of PPE). Besides, global genetic variability shows significant differentiations inside, and between, the different transects. Genetic diversity is a necessary prerequisite for adaptation. Therefore, subpopulations at the highest elevations would have less adaptative potentialities than those at lower elevations.