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Scientists and society are increasingly becoming aware of loss of insect biodiversity and biomass. The level of biodiversity determines the efficiency of ecological communities to capture essential resources, produce biomass, decompose and recycle nutrients. Relationships between plant and insect diversity can be modified by changes in insect abundance. This study determined the associations between microclimate and diversity of forest plants on overall insect abundance and abundances of different insect orders in the canopy of temperate deciduous forests dominated by Fagus sylvatica L. (European beech; Fagaceae) in Central Germany. Following model selection, a linear mixed model was used to analyse the associations between abiotic factors (air temperature and relative humidity) as well as biotic factors (species richness and cover for the ground, shrub and tree layer) and insect abundance and abundances of insect orders. Within similar strength of evidence, best models were chosen as those with a single explanatory parameter. Significant associations were recorded between abundances of Lepidoptera and Neuroptera and relative air humidity, insect abundance and species richness in the shrub layer, and between abundances of Diptera and Psocoptera and percentage cover of shrubs. Trends in associations were detected between the abundance of Hemiptera and species richness recorded in the shrub layer, and between the abundance of Thysanoptera and the species richness in the ground layer. No significant associations with single explanatory parameters were recorded for the abundances of Coleoptera and Hymenoptera. Phytodiversity, especially that in the shrub layer, were more often associated with the abundances of insect orders than microclimatic factors. The potential importance of the association between shrub layer parameters and the abundance of insects might be based on the shrub layer combining the associations with the ground layer (bottom-up processes) and canopy layer (environmental conditions). In addition, associations between phytodiversity and abundance of insects seem to vary most for Coleoptera and Hymenoptera in which there are markedly different functional groups. [ABSTRACT FROM AUTHOR]

Questions: To improve our knowledge on how environmental conditions determine the development of high‐value Calluna vulgaris heathland habitats, we studied the floristic and structural characteristics of heathland plant communities across North Germany and how they are influenced by edaphic, climatic and management factors. We ask how heathland development is related to these factors and what are the implications for conservation management and restoration. Location: North German Plain. Methods: We collected 350 relevés in 18 dry Calluna heathland areas. Plant communities were classified using Isopam, and Redundancy Analysis (RDA) determined effects of environmental conditions. Potential pathways of development and the nature conservation status of the communities were identified on a multifactorial basis. Results: We found nine floristically and structurally distinct heathland plant communities. Heathland vegetation showed distinct patterns along Calluna age development stages and environmental conditions. Soil conditions and related effects of long‐term site history and recent management turned out to be the predominant factors influencing species composition and diversity, resulting in three potential heathland succession pathways. Mosaic‐like communities with particularly high taxonomic diversity and conservation value occurred on early‐successional inland dunes or as regeneration stage growing on nutrient‐poor sandy soils without humus accumulation. Conclusions: The study reveals fundamental differences between historically farmed heathland in the oceanic Northwest and former military training areas mainly in northeastern Germany with consequences for restoration ecology. Present nature conservation criteria turned out to be insufficient in predicting habitat quality, as lichens are frequently disregarded. Our findings highlight the need for intense soil disturbance to maintain early‐stage soil conditions and a diverse Calluna growth‐phase composition, as these factors essentially determine species richness in lowland heaths. [ABSTRACT FROM AUTHOR]

Extensive green roofs (EGRs) offer several beneficial ecosystem services for sustainable urban development. However, most standard green roofs have been designed with species-poor plant mixtures containing non-native species. Aiming to increase the nature conservation values of EGRs, we developed and tested a vascular plant seed mixture including regionally occurring native sandy dry grassland species in experimental miniature roofs in Northwestern Germany (temperate oceanic climate) over 4 years. We tested the mixture at two seed densities (1 and 2 g/m2). Additionally, we tested seeding at 1 g/m2 and introducing raked plant material collected from an ancient dry grassland. The total establishment rates of sown species reached 92–96% in the first year, but dropped to 40–60% in the last 2 years, with the highest values for the plots with raked material. Twenty-four additional species (11 vascular, 7 lichen, and 6 moss species, including 7 red-list species) typical of sandy dry grasslands were introduced through the raked material. Vascular plants reached 60–70% cover in the second year. Severe drought periods in the third and the fourth year led to a strong decline of vascular plant cover then. As this cover was higher in the plots with raked material, we assume facilitative effects through the well-developed cryptogam layer containing a mix of pleurocarpous and acrocarpous mosses and lichens. Spontaneously establishing acrocarpous mosses in sown plots did not seem to provide this same function. We conclude that EGRs designed with regionally occurring sandy dry grassland plant species and especially the application of raked plant material from ancient grassland is a fruitful approach to increase the value of green roofs for native phytodiversity. [ABSTRACT FROM AUTHOR]