Effects of land-use changes on plants in European mountains

Since a few decades land-use changes have gained increasing importance as driving forces of changes in vegetation and landscape pattern in Europe. Effects of land-use changes may be particularly striking and long-lasting in mountain areas, which are characterized by a high ecological complexity and sensitivity. Land-use changes can affect plant species to a great extent by altering resource availability for plants. Plants respond to changing resource availability by morphological and physiological adaptations, which may affect resource uptake and resource use. Within the EU-TERI project ECOMONT effects of land-use changes on plant species are being investigated for an Eastern Alpine transect, defining patterns of species` reponse to altered resource levels in the field. To be able to account for resource effects and resource interactions which are related to the socio-economic background, land- use history and current land-use, as well as climate, a further step requires to extend such investigations in a comparative manner to other mountain regions differing in these background conditions. The proposed project aims to define effects of land-use changes on resource availability and resource use of plant species in different mountain regions of Europe. comparing selected species in the Spanish Pyrennees, the Scottish Highlands and the Alps. In particular it aims i. to investigate in what way and to what extent land-use changes in different mountain areas affect the availability of the resources light, nitrogen and water for plants that are typical of ecosystems under different land-use, and how species respond in situ to such changes in resource availability; ii. to assess whether there is a general pattern of changing resource availability and resource limitation for plants when mountain pastures and meadows are abandoned or whether different plant species, types of succession or mountain regions evoke different patterns; iii. to determine whether and to what extent changes in resource limitations as well as plant responses are similar for a single species growing in different mountain regions of Europe. Resource effects on plant species will be assessed by combining environmental, morphological and physiological parameters measured in the field and upscaling from organ to whole plant processes to determine key parameters of light. nitrogen and water use of species in ecosystems under different land-use. The approach will be strictly comparative and will focus on species or pairs of species that grow in all the mountain regions investigated. The proposed project will permit to extend investigations on plant species from a few pilot research areas in the Eastern Alps to different mountain regions of Europe, which allows to draw more generalized conclusions on resource availability, resource acquisition and resource limitations and their implications for plant performance following land-use changes in mountain areas.

Since a few decades land-use changes have gained increasing importance as driving forces of changes in vegetation and landscape pattern in Europe. Effects of land-use changes may be particularly striking and long-lasting in mountain areas, which are characterized by a high ecological complexity and sensitivity. The project aimed to define effects of land-use changes on the resource availability and resource use of plant species in different mountain grasslands across Europe, comparing selected species in the Spanish Pyrenees, the Scottish Highlands and the Alps. The research sites differ with respect to climate, current and historical land use and therefore provide an opportunity to distinguish between site-specific and general effects of land use on plants. Resource effects on plant species were assessed by combining environmental, morphological and physiological parameters measured in the field and up-scaling from organ to whole plant processes to determine key parameters of light, nitrogen and water use of species in ecosystems under different land-use. It was generally found that with decreasing intensity of land use nitrogen availability decreased for plants, which resulted in a decrease in leaf nitrogen concentrations and photosynthetic capacity. Light availability to plants increased from meadows to abandoned meadows and pastures and was highest on grazed sites. Whole plant photosynthesis, which is a good indicator of plant light and nitrogen use, however, was not consistently affected by land use, since due to altered nitrogen availability plant size decreased with increasing light availability. Besides these general trends, some site-specific differences were observed. It was found that with increasing altitude of the studied site plant leaf areas decreased, which resulted in lower rates of plant photosynthesis. Furthermore, lower nitrogen availability at the Scottish sites resulted in a more efficient nitrogen use by plants. Water availability was found to play a minor role during the period of maximum plant growth at any of the sites studied. Based on data of a previous EU-project and the completed project it was possible to establish a comprehensive data base of plant functional traits in European mountain grasslands differing in land use, which may serve as baseline for assessing implications of global changes on the relationship of biodiversity and ecosystem processes.