Plant functional strategies and environmental constraints in Mediterranean high mountain grasslands in central Spain

Abstract

Background: The relationship between plant traits and environmental factors will be of value in understanding of functional strategies that plants have developed to cope with the environmental constraints on plant life in Mediterranean high mountain ecosystems. Aims: The aims of this study were (1) to explore the variation in plant traits in relation to environmental variability; (2) to analyse the functional strategies of species; and (3) to assess the habitat constraints for the species in the study area. Methods: We sampled the floristic composition of 76 1 m × 1 m plots on five summits over 2,100 m above sea level in the mountains of the Sistema Central, Spain. Soil properties and temperature and grazing disturbance parameters were recorded. Eight plant traits were assessed in 21 species. Environmental variability and the co-variation of functional traits were analysed by RDA and PCA, respectively. Plant traits and environmental variability were related using fourth-corner analysis. Results: Traits related to resource acquisition, such as leaf size and N concentration, varied with soil temperature and estimated summer water availability. Leaf dry matter content was found to be related to estimated water availability and soil pH. Seed mass was a factor of snow cover duration and water availability, and clonality to the duration of the vegetative period and estimated water availability. Grazing disturbance was related to the mean plant height of the species. Conclusions: The results suggest that low temperatures, rather than water shortage, may be the principal limiting factor for resource acquisition in plants. Nevertheless species establishment is limited by water shortage during summer in these Mediterranean high mountain communities.