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The abandonment of marginally productive habitats and the intensification of land use on productive sites have caused transformative changes in vegetation composition in Central Europe. In this study, after 25 years we resurveyed a total of 145 grassland relevés from the mid-1990s in a grassland-dominated valley of the Northern Alps of Upper Austria. We studied changes in richness and composition, and related these to underlying drivers. We found that the average species number in plots increased from 46 in the first survey period to 49 in the second one. Median species richness across sites significantly increased from 1995 to 2020 for Festuco-Brometea (55-61 species) and Galio-Urticetea (24-32 species), but did not show any significant change for the other classes. Further, we recorded substantial species turnover, with winners consisting mostly of species that prefer nutrient-rich sites, while losers were predominantly species of nutrient-poor sites. In particular, using Ellenberg Indicator Values for calculating community indices, we found an indication for ongoing eutrophication in vegetation types of nutrient-poor vegetation classes (Festuco-Brometea and Calluno-Ulicetea), and in wet habitats (Scheuchzerio-Caricetea fuscae). Community indices of wet habitats also showed clear signs of becoming more mesic. Thermophilization of community indices was evident across several vegetation classes. Further, alien species that were very rare in the mid-1990s became more abundant in the resurveyed plots, although the level of invasion is still low. Finally, community values for nutrients of plots that are located in a protected area that has been established in 2014 did not increase significantly, while this was the case in plots outside the protected area, indicating that the management of the protected area has positive effects in halting eutrophication. We conclude that despite overall species richness changing only moderately between both surveys, substantial changes in community composition toward more nitrophilic and thermophilic conditions occurred. [ABSTRACT FROM AUTHOR]

Although plants and soil biota have mutual functional links as producers and decomposers in terrestrial ecosystems, less is known about structural linkages between above-ground and below-ground communities. For this study, we examined whether plant species richness and soil microbial richness are related to each other, and how their richness is related to soil fertility and herbivore activity at 24 plots of the Shiriyazaki seminatural grassland in northern Japan. Prokaryote (bacterial) richness and eukaryote richness were evaluated by the band number of denaturing gradient gel electrophoresis (DGGE) using 16S and 18S ribosomal DNA fragments. Plant species richness was negatively related to soil nitrogen availability and phosphorus content. Prokaryote richness showed a negative correlation with soil phosphorus contents and no significant correlation with vegetation structure (height, richness and functional type composition). Eukaryote (mainly fungi) richness showed significant positive correlations with plant species richness, community height and forb species composition. These results suggest that bacterial richness is influenced by soil properties, whereas eukaryote richness is associated closely with vegetation structure. [ABSTRACT FROM AUTHOR]

The invasion of non-native earthworms ( spp.) into a small number of intensively studied stands of northern hardwood forest has been linked to declines in plant diversity and the local extirpation of one threatened species. It is unknown, however, whether these changes have occurred across larger regions of hardwood forests, which plant species are most vulnerable, or with which earthworm species such changes are associated most closely. To address these issues we conducted a regional survey in the Chippewa and Chequamegon national forests in Minnesota and Wisconsin (U.S.A.), respectively. We sampled earthworms, soils, and vegetation, examined deer browse in 20 mature, sugar-maple-dominated forest stands in each national forest, and analyzed the relationship between invasive earthworms and vascular plant species richness and composition. Invasion by was a strong indicator of reduced plant richness in both national forests. The mass of juveniles was significantly and negatively related to plant-species richness in both forests. In addition, was a significant factor affecting plant richness in a full model that included multiple variables. In the Chequamegon National Forest earthworm mass was associated with higher sedge cover and lower cover of sugar maple seedlings and several forb species. The trends were similar but not as pronounced in Chippewa, perhaps due to lower deer densities and different earthworm species composition. Our results provide regional evidence that invasion by species may be an important mechanism in reduced plant-species richness and changes in plant communities in mature forests dominated by sugar maples. [ABSTRACT FROM AUTHOR]