The functional diversity and composition of plant traits within communities are tightly linked to important ecosystem functions and processes. Whereas vegetative traits reflecting adaptations to environmental conditions are commonly assessed in community ecology, floral traits are often neglected despite their importance for the plants' life cycle. The consideration of floral traits covers important aspects such as sexual plant reproduction and pollinator diversity, which remain unobserved in studies focussing on vegetative traits only. To test whether vegetative and floral traits differ in their responses to elevation, we measured morphological and chemical traits of plant species occurring in pastures at seven elevations in the Austrian Alps. Variation in functional composition was examined using the concept of n-dimensional hypervolumes and vector analysis. Our data show that vegetative and floral traits vary differently with the elevational gradient. Whereas vegetative traits changed in a predictable manner with elevation, floral traits did not specifically respond to elevation. Overall variation in vegetative traits mainly resulted from phenotypical differences between plants in different elevations, whereas total variation in floral traits was a result from a high variation within communities. The assessment of functional changes in vegetative and floral traits along mountain slopes thus reveals different patterns in plant responses to elevation and may help to generate testable hypotheses on functional responses to current climate warming.
Floral scents serve multiple functions in the interactions with organisms. Flowers of Achillea millefolium (Asteraceae) emit scent bouquets dominated by terpenoids. These flowers are mainly visited by flies and beetles, whereas bumblebees, common visitors at other Asteraceae, are absent from A. millefolium flowers. In order to test how a reduced mono- and sesquiterpenoid emission affect insect behaviour we inhibited the biochemical pathways towards the production of terpenoids of A. millefolium plants and conducted behavioural choice tests. The inhibition resulted in reduced emission rates of most mono- and sesquiterpenes and thus altered the olfactory phenotype of the flowers. In a flight cage, flies usually chose flowers with a natural scent bouquet, bumblebees clearly preferred flowers treated with inhibitors. These findings confirm that floral scents play a pronounced role in foraging decisions of flower visiting insects and support the notion that responses towards scent are animal species-specific emphasising the role of scents as floral filters.
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