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Aim: We test whether urbanization drives biotic homogenization. We hypothesize that declines in abundance and species diversity of aerial insects are exacerbated by the urbanization‐driven loss of species with low habitat generalism, mobility and warm‐adaptedness. We predict this homogenization to be more pronounced for nocturnal taxa, and at wider scales for mobile taxa. Location: Belgium. Time period: Summers 2014–2015. Major taxa studied: Lepidoptera. Methods: We compare communities along urbanization gradients using a shared, replicated and nested sampling design, in which butterflies were counted within 81 grassland and macro‐moths light‐trapped in 12 woodland sites. We quantify taxonomic and functional community composition, the latter via community‐weighted means and variation of species‐specific traits related to specialization, mobility and thermophily. Using linear regression models, variables are analysed in relation to site‐specific urbanization values quantified at seven scales (50–3,200 m radii). At best‐fitting scales, we test for taxonomic homogenization. Results: With increasing urbanization, abundance, species richness and Shannon diversity severely declined, with butterfly and macro‐moth declines due to local‐ versus landscape‐scale urbanization (200 vs. 800–3,200 m radii, respectively). While taxonomic homogenization was absent for butterflies, urban macro‐moth communities displayed higher nestedness than non‐urban communities. Overall, communities showed mean shifts towards generalist, mobile and thermophilous species, displaying trait convergence too. These functional trait models consistently fit best with urbanization quantified at local scales (100–200 m radii) for butterfly communities, and at local to wider landscape scales (200–800 m radii) for macro‐moth communities. Main conclusions: Urban communities display functional homogenization that follows urbanization at scales linked to taxon‐specific mobility. Light pollution may explain why homogenization was more pronounced for the nocturnal taxon. We discuss that urbanization is likely to impact flying insect communities across the globe, but also that impacts on their ecosystem functions and services could be mitigated via multi‐scale implementation of urban green infrastructure. [ABSTRACT FROM AUTHOR]

Aims We aim to document elevational richness patterns of geometrid moths in a globally replicated, multi-gradient setting, and to test general hypotheses on environmental and spatial effects (i.e. productivity, temperature, precipitation, area, mid-domain effect and human habitat disturbance) on these richness patterns. Location Twenty-six elevational gradients world-wide (latitudes 28° S to 51° N). Methods We compiled field datasets on elevational gradients for geometrid moths, a lepidopteran family, and documented richness patterns across each gradient while accounting for local undersampling of richness. Environmental and spatial predictor variables as well as habitat disturbance were used to test various hypotheses. Our analyses comprised two pathways: univariate correlations within gradients, and multivariate modelling on pooled data after correcting for overall variation in richness among different gradients. Results The majority of gradients showed midpeak patterns of richness, irrespective of climate and geographical location. The exclusion of human-affected sampling plots did not change these patterns. Support for univariate main drivers of richness was generally low, although there was idiosyncratic support for particular predictors on single gradients. Multivariate models, in agreement with univariate results, provided the strongest support for an effect of area-integrated productivity, or alternatively for an elevational area effect. Temperature and the mid-domain effect received support as weaker, modulating covariates, while precipitation-related variables had no explanatory potential. Main conclusions Despite the predicted decreasing diversity-temperature relationship in ectotherms, geometrid moths are similar to ants and salamanders as well as small mammals and ferns in having predominantly their highest diversity at mid-elevations. As in those comparative analyses, single or clear sets of drivers are elusive, but both productivity and area appear to be influential. More comparative elevational studies for various insect taxa are necessary for a more comprehensive understanding of elevational diversity and productivity. [ABSTRACT FROM AUTHOR]

1. Light traps are used to make inferences about local macro-moth communities, but very little is known about the efficiency with which they attract moths from varying distances, and how this may differ among families. 2. We released 731 marked individuals, from three of the most common and species-rich macro-moth families, at several distances from low-wattage actinic light traps in open and woodland habitat. 3. Logistic regression showed family-specific sampling areas: erebids were attracted from up to 27 m, geometrids from up to 23 m, and noctuids from up to 10 m from the light source, with these distances corresponding to a 5% recapture rate. Sampling size was also family-specific: a maximum of 55% of erebids, 15% of geometrids, and 10% of noctuids were predicted to be trapped when flying near (0-1 m) light traps. 4. Our study demonstrates that weak light traps: (i) have remarkably local sampling ranges, resulting in samples that are highly representative of the local habitat, and (ii) attract small, and family-specific proportions of individuals within these ranges. 5. We suggest that the local sampling ranges of weak light traps make them excellent tools to monitor nocturnal macro-moth communities. As trap efficiency differs among macro-moth families, care must be taken in relating the abundance of the sample to absolute local abundance. Frequent sampling can provide adequate data on relative temporal change in the local macro-moth fauna, however. [ABSTRACT FROM AUTHOR]

. 1. Agricultural intensification has contributed to severe declines in odonate (dragonfly and damselfly) populations. The objective of our study is to benefit current measures for the conservation of odonates by establishing the conditions favourable to Odonata and focusing on ponds within agricultural land. 2. Our landscape-scale study used exuvial counts and habitat measurements from 29 ponds across a catchment in England, over 3 years, to determine key factors affecting odonate abundance and species richness. 3. Ponds dominated by floating and submerged vegetation were the most transparent, supported the highest abundance and species richness of exuviae, and were always fully or partially surrounded by buffer strips. Ponds lacking vegetation were turbid, yielding no exuviae even if they were buffered. English agri-environment schemes (AES) currently support pond and buffer strip creation and management. 4. Abundance of exuviae was higher in recently created ponds compared to older ponds, whereas ponds that had dried out the previous summer had fewer exuviae. 5. Species richness of exuviae decreased with increasing distance to the nearest viable pond, falling by more than 40% for distances over 100 m. 6. We conclude that odonate conservation would be more effective if AES would consider the spatial scale at which ponds are created and the location, type, and quality of ponds targeted for buffer strips. [ABSTRACT FROM AUTHOR]

Abstract: Agricultural intensification has contributed to severe declines in odonate (dragonfly and damselfly) populations. Odonates require healthy waterbodies for their larval stages and resource-rich terrestrial landscapes as adults. As such, farmland management at both local and larger landscape scales may be needed to reverse population declines. We sampled odonate adults and exuviae from lowland farmland ponds in England, to investigate relationships between odonate species richness and surrounding land-use. The more mobile dragonflies (Anisoptera) were influenced most strongly by landscape variables at the largest scale (i.e. 1600m radius), while less mobile damselflies (Zygoptera) were affected by variables at more local scales (i.e. 100/400m radii). A greater number of landscape variables affected exuvial species richness compared to adult species richness. Exuvial species richness was higher when 2m wide cross-compliance buffer strips around ponds were present. However, no ponds in the study had buffer strips that were established through England''s basic agri-environment scheme (Entry Level Scheme: ELS) agreements, and we observed a negative relationship between ELS area and exuvial species richness. Exuvial species richness increased with the amount of water, but not the number of ponds, in the landscape surrounding a focal pond. The observed odonate responses to local and surrounding land-use lend support to the development of agri-environment scheme policies that encourage landscape-scale, as well as local, scheme implementation and management. We predict that both landscape-scale and quality-targeted management of farmland ponds would benefit odonates, irrespective of mobility level and life-stage. [Copyright &y& Elsevier]