No abstract

Questions To what extent do changes in management (abandonment and fertilization) affect plant functional and taxonomic diversity in wet meadow communities? To what extent do the changes in functional and taxonomic diversity depend on site productivity? Location Železné hory Mts., Czech Republic. Methods Experimental plots were established on 21 wet meadows differing in productivity and species composition. In each meadow, in 2007, four 1 × 1 m plots were established, representing a full factorial design with abandonment and fertilization as the factors. In each plot, the number of species present was recorded in 100 subplots (0.1 × 0.1 m) in the years 2007, 2009 and 2011. Different indicators of functional diversity (functional richness, functional evenness, and Rao′s quadratic entropy) were calculated using five functional traits (SLA, LDMC, seed mass, plant height and clonality). Both abundance‐weighted and non‐weighted diversity indices were calculated. Randomization tests (conducted with PERMANOVA) were used to assess the effect of site productivity and management on both α‐ and β‐diversity components. Results Meadows along the productivity gradient differed in functional and taxonomic diversity. Both abandonment and fertilization decreased taxonomic diversity. Whereas fertilization decreased functional richness and Rao′s quadratic entropy, abandonment decreased functional evenness. The changes in both taxonomic and functional diversity caused by abandonment and fertilization occurred faster in more productive meadows. Conclusions The increased dominance of tall species with abandonment and fertilization, followed by the loss of species and the decrease in various indicators of functional diversity, suggest that increased competition for light resulted in increased trait convergence among co‐existing species. In addition, many processes occurring after abandonment and fertilization depend on meadow productivity. Results suggest that abundance‐ and non‐abundance‐weighted diversity indices give complementary insights on community structure. These results imply that changes are needed in current meadow management and conservation.

Since the time of Darwin, biologists have considered the floral nectar spur to be an adaptation representing a high degree of plant specialization. Nevertheless, some researchers suggest that nature is more complex and that even morphologically specialized plants attract a wide spectrum of visitors. We observed visitors on Impatiens burtonii (Balsaminaceae) and measured the depth of the proboscis insertion into the spur, the distance of the nectar surface from the spur entrance and the visitor's effectiveness. The hoverfly Melanostoma sp., with the shortest proboscis, was most active early in the morning and fed on pollen and nectar near the spur entrance. The honeybee Apis mellifera and the hoverfly Rhingia mecyana were the most frequent visitors before and after noon, respectively. Although R. mecyana, the only visitor able to reach the end of the spur, was the most frequent, it did not deposit the largest number of pollen grains per visit. Nectar spurs may function as complex structures allowing pollination by both short- and long-proboscid visitors and separating their spatial and temporal niches. Spurred plants should be considered as more generalized and exposed to more diverse selection pressures than previously believed.