Meta-analysis identifies native priority as a mechanism that supports the restoration of invasion-resistant plant communities.

The restoration of invasion-resistant plant communities is an important strategy to combat the negative impacts of alien invasions. Based on a systematic review and meta-analysis of seed-based ecological restoration experiments, here we demonstrate the potential of functional similarity, seeding density and priority effect in increasing invasion resistance. Our results indicate that native priority is the most promising mechanism to control invasion that can reduce the performance of invasive alien species by more than 50%. High-density seeding is effective in controlling invasive species, but threshold seeding rates may exist. Overall seeding functionally similar species do not have a significant effect. Generally, the impacts are more pronounced on perennial and grassy invaders and on the short-term. Our results suggest that biotic resistance can be best enhanced by the early introduction of native plant species during restoration. Seeding of a single species with high functional similarity to invasive alien species is unpromising, and instead, preference should be given to high-density multifunctional seed mixtures, possibly including native species favored by the priority effect. We highlight the need to integrate research across geographical regions, global invasive species and potential resistance mechanisms.

Estimates of regeneration potential in the Pannonian sand region help prioritize ecological restoration interventions.

Restoration prioritization helps determine optimal restoration interventions in national and regional spatial planning to create sustainable landscapes and maintain biodiversity. Here we investigate different forest-steppe vegetation types in the Pannonian sand region to provide restoration recommendations for conservation management, policy and research. We create spatial trajectories based on local, neighbouring and old-field regeneration capacity estimates of the Hungarian Habitat Mapping Database, compare the trajectories between different mesoregions and determine which environmental predictors possibly influence them at the mesoregion level using a random forest model. The trajectories indicate which types of passive or active restoration intervention are needed, including increasing connectivity, controlling invasive species, or introducing native species. Better restoration results can be achieve in the vicinity of larger (semi-)natural areas, but the specific site conditions must also be taken into account during prioritization. We also propose large-scale grassland restoration on abandoned agricultural fields instead of industrial forest plantations and afforestation with non-native species.

Meta-analysis of multidecadal biodiversity trends in Europe.

Local biodiversity trends over time are likely to be decoupled from global trends, as local processes may compensate or counteract global change. We analyze 161 long-term biological time series (15-91 years) collected across Europe, using a comprehensive dataset comprising ~6,200 marine, freshwater and terrestrial taxa. We test whether (i) local long-term biodiversity trends are consistent among biogeoregions, realms and taxonomic groups, and (ii) changes in biodiversity correlate with regional climate and local conditions. Our results reveal that local trends of abundance, richness and diversity differ among biogeoregions, realms and taxonomic groups, demonstrating that biodiversity changes at local scale are often complex and cannot be easily generalized. However, we find increases in richness and abundance with increasing temperature and naturalness as well as a clear spatial pattern in changes in community composition (i.e. temporal taxonomic turnover) in most biogeoregions of Northern and Eastern Europe.