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Massive declines in insect biodiversity and biomass are reported from many regions and habitats. In urban areas, creation of native wildflower meadows is one option to support insects and reduce maintenance costs of urban green spaces. However, benefits for insect conservation may depend on previous land use, and the size and location of new wildflower meadows. We show effects of conversion of roadside plantings–from exotic shrubs into wildflower meadows–on (1) the abundance of 13 arthropod taxa–Opiliones, Araneae, Isopoda, Collembola, Orthoptera, Aphidoidea, Auchenorrhyncha, Heteroptera, Coleoptera, Nematocera, Brachycera, Apocrita, Formicidae–and (2) changes in maintenance costs. We assessed the influence of vegetation type (meadow vs. woody), meadow age, size, location (distance to city boundary), and mowing regime. We found many, but not all, arthropod taxa profiting from meadows in terms of arthropod activity abundance in pitfall traps and arthropod density in standardized suction samples. Arthropod number in meadows was 212% higher in pitfall traps and 260% higher in suction samples compared to woody vegetation. The increased arthropod number in meadows was independent of the size and isolation of green spaces for most taxa. However, mowing regime strongly affected several arthropod taxa, with an increase of 63% of total arthropod density in unmown compared to mown meadow spots. Costs of green space maintenance were fivefold lower for meadows than for woody vegetation. Our study shows that (1) many different arthropod taxa occur in roadside vegetation in urban areas, (2) replacement of exotic woody vegetation by native wildflower meadows can significantly increase arthropod abundance, especially if meadow management permits temporarily unmown areas, and (3) maintenance costs can be considerably reduced by converting woody plantings into wildflower meadows. Considering many groups of arthropods, our study provides new insights into possible measures to support arthropods in urban environments. [ABSTRACT FROM AUTHOR]

Intensive land use is a driving force for biodiversity decline in many ecosystems. In semi-natural grasslands, land-use activities such as mowing, grazing and fertilization affect the diversity of plants and arthropods, but the combined effects of different drivers and the chain of effects are largely unknown. In this study we used structural equation modelling to analyse how the arthropod communities in managed grasslands respond to land use and whether these responses are mediated through changes in resource diversity or resource quantity (biomass). Plants were considered resources for herbivores which themselves were considered resources for predators. Plant and arthropod (herbivores and predators) communities were sampled on 141 meadows, pastures and mown pastures within three regions in Germany in 2008 and 2009. Increasing land-use intensity generally increased plant biomass and decreased plant diversity, mainly through increasing fertilization. Herbivore diversity decreased together with plant diversity but showed no response to changes in plant biomass. Hence, land-use effects on herbivore diversity were mediated through resource diversity rather than quantity. Land-use effects on predator diversity were mediated by both herbivore diversity (resource diversity) and herbivore quantity (herbivore biomass), but indirect effects through resource quantity were stronger. Our findings highlight the importance of assessing both direct and indirect effects of land-use intensity and mode on different trophic levels. In addition to the overall effects, there were subtle differences between the different regions, pointing to the importance of regional land-use specificities. Our study underlines the commonly observed strong effect of grassland land use on biodiversity. It also highlights that mechanistic approaches help us to understand how different land-use modes affect biodiversity. [ABSTRACT FROM AUTHOR]

Trait-based approaches have increased significantly in community ecology during the last decade. This is not least because studies on biodiversity–ecosystem functioning relationships became a major topic in ecology. Species’ functions in ecosystems are mediated by their traits. For a better understanding of the relationships between environmental drivers, the community composition of organisms and ecosystems functioning, it is crucial to understand how these relationships are mediated by the communities’ trait composition. While there are world-wide efforts to set up trait databases, most have so far focused on plants and species-poorer taxa such as birds or amphibians. In contrast, for insects, the large number of species makes the gathering of comparable trait data a challenging task. In addition, there is the danger that generic trait information, which is available from common textbooks, may not be sufficient to detect the response of insect communities to environmental change or the consequences of trait changes for ecosystem functioning. One method to overcome this is to take morphometric measurements of species. In this study we measured morphometric traits of a total of 179 Heteroptera species that were sampled by sweep-netting on a total of 150 managed grassland plots across three regions in Germany between 2008 and 2012. These plots represent the whole range of grassland management intensities from extensively used pastures to mown pastures to intensively managed and fertilized meadows. In this paper we provide a database of mean values of 23 morphometric measures across sex and morphotypes for each sampled Heteroptera species. Morphological traits are assumed to be related to their adaptation and function in the environment. Thus the relative morphometric traits can be used as proxies for ecological features of a species that may affect its performance or fitness. Our database can be used by future trait-based studies for developing and testing hypotheses of the functional significance of these traits. Examples include studying the functional responses of insect communities to environmental drivers or studying how the change in trait composition affects ecosystem processes. [ABSTRACT FROM AUTHOR]