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.