Ecological intensification: multifunctional flower strips support beneficial arthropods in an organic apple orchard

Flower strips are a fundamental part of agri-environment schemes in the Common Agricultural Policy (CAP). Although vegetation is central for many arthropod groups, a few studies have evaluated the effects of flower strip structural and functional attributes on arthropod communities. In this study, we explored the relationship between flower strip attributes and the abundance of different arthropod functional groups in annual flower strips located in an organic apple orchard. We surveyed plant and arthropod communities in 30 1 m x 6 m plots. In each plot, we collected data on species composition and vegetation structure (e.g., total cover, density, number of floral displays). For each plant species, we also retrieved data on leaf palatability and nutritional value. Arthropods were collected using sweep netting technique. Structural and functional attributes of the flower strip revealed a crucial role in regulating arthropod abundance, which however depended on the specific arthropod functional group. We identified three main attributes (plant species richness, composition, and vegetation density) of flower strips that should be considered when implementing multifunctional flower strips. Specifically, plant species richness to ensure complementarity of resources and niches, plant species composition to ensure complementary floral resources, and vegetation density to ensure sheltering microhabitats and suitable microclimatic conditions and to increase the density of floral resources. Our results suggest that by considering structural and functional attributes of flower strips, it is possible to design multifunctional flower strips with greater effectiveness as measures for ecological intensification

Different distribution patterns of hoverflies (Diptera: Syrphidae) and bees (Hymenoptera: Anthophila) along altitudinal gradients in Dolomiti Bellunesi National Park (Italy)

Hoverflies (Diptera: Syrphidae) and bees (Hymenoptera: Anthophila) are two key taxa for plant pollination. In the present research, the altitudinal distribution of these taxa was studied along two gradients (elevation range: 780–2130 m) in the Dolomiti Bellunesi National Park (Northeastern Italy). Pan traps were used as a sampling device to collect both hoverflies and bees. Other than altitude, the effect of landscape complexity and plant diversity were considered as potential predictors of hoverfly and bee richness and abundance along the two gradients. A total of 68 species of hoverflies and 67 of bees were collected during one sampling year, confirming the efficacy of pan traps as a sampling device to study these taxa. Altitude was the main variable affecting both hoverfly and bee distribution. The two taxa show different distribution patterns: hoverflies have a unimodal distribution (richness and abundance) with peak at middle altitude (1500 m), while bees have a monotonic decline (richness and abundance) with increasing altitude. Both hoverfly and bee populations change with the increasing altitude, but the change in hoverflies is more pronounced than in bees. Species turnover dominates the β-diversity both for hoverflies and bees; therefore, the hoverfly and bee communities at higher altitudes are not subsamples of species at lower altitude but are characterized by different species. This poses important conservation consequences. Some rare species, typical of an alpine habitat were recorded; the present research represents important baseline data to plan a monitoring scheme aimed at evaluating the effect of climate change on pollinators in these fragile habitat

Ground-dwelling arthropods as biodiversity indicators in maize agroecosystems of Northern Italy

Reliable monitoring of arthropod diversity in a given agroecosystem is essential for the conservation of the related ecosystem services, such as biological control. The often daunting complexity of arthropod collection and identification, however, highlights the need for surrogate taxa that can be easily sampled and be representative of a number of other taxa in term of diversity, general community features and specific composition. In this study, we used pitfall traps to sample three ground-dwelling arthropod taxa important as biocontrol agents (ground beetles, rove beetles and spiders) in 9 conventionally managed maize agroecosystems of Northern Italy over the course of two years, with the goal of characterizing their assemblages and evaluating their reciprocal potential as indicators of activity density, species richness, community turnover and species co-occurrence. Although dominated by few generalist species, sampled arthropod communities were relatively species-rich, and included the first Italian record of the spider Zelotes metellus (Roewer) (Araneae: Gnaphosidae). Ground beetles as a group were confirmed as promising indicators for the species richness and community composition turnover of rove beetles and spiders. Additionally, several abundant arthropod species acted as indicators of the species richness of their respective groups, and the ground beetle Pterostichus macer (Marsham) also worked as an indicator of overall rove beetle activity density. While the co-occurrence of individual arthropod species was limited for the studied taxa, a few species such as the ground beetle Parophonus maculicornis (Duftschmid) did show promise as species-specific bioindicators. Our results could be useful in improving the monitoring and management of these important natural enemies in maize-growing regions

Artenvielfalt auf biologischen und nicht-biologischen Landwirtschaftsbetrieben in zehn europäischen Regionen

One of the aims of organic farming is the protection of biodiversity. In the EU FP7 project BioBio, we studied the effect of organic farming on species numbers at farm level on 169 randomly selected organic and non-organic farms with mostly low to medium intensity in ten European regions. Using a preferential sampling scheme based on habitat mapping, numbers of plants, earthworms, spiders and bees were assessed at farm level. A global analysis across the ten regions shows that organic farms have significantly higher numbers of plant and bee species than non-organic farms. The effect of organic farming on earthworm and spider species numbers are also positive but insignificant. The effects in absolute terms are small and much smaller than the variation between individual farms. Currently ongoing analyses aim at identifying the important driving factors for farmland biodiversity

Farmland biodiversity and agricultural management on 237 farms in 13 European and two African regions

Farmland is a major land cover type in Europe and Africa and provides habitat for numerous species. The severe decline in farmland biodiversity of the last decades has been attributed to changes in farming practices, and organic and low-input farming are assumed to mitigate detrimental effects of agricultural intensification on biodiversity. Since the farm enterprise is the primary unit of agricultural decision making, management-related effects at the field scale need to be assessed at the farm level. Therefore, in this study, data were collected on habitat characteristics, vascular plant, earthworm, spider, and bee communities and on the corresponding agricultural management in 237 farms in 13 European and two African regions. In 15 environmental and agricultural homogeneous regions, 6–20 farms with the same farm type (e.g., arable crops, grassland, or specific permanent crops) were selected. If available, an equal number of organic and non-organic farms were randomly selected. Alternatively, farms were sampled along a gradient of management intensity. For all selected farms, the entire farmed area was mapped, which resulted in total in the mapping of 11 338 units attributed to 194 standardized habitat types, provided together with additional descriptors. On each farm, one site per available habitat type was randomly selected for species diversity investigations. Species were sampled on 2115 sites and identified to the species level by expert taxonomists. Species lists and abundance estimates are provided for each site and sampling date (one date for plants and earthworms, three dates for spiders and bees). In addition, farmers provided information about their management practices in face-to-face interviews following a standardized questionnaire. Farm management indicators for each farm are available (e.g., nitrogen input, pesticide applications, or energy input). Analyses revealed a positive effect of unproductive areas and a negative effect of intensive management on biodiversity. Communities of the four taxonomic groups strongly differed in their response to habitat characteristics, agricultural management, and regional circumstances. The data has potential for further insights into interactions of farmland biodiversity and agricultural management at site, farm, and regional scale

Il ruolo dei Sirfidi nell'agricoltura sostenibile: analisi del potenziale delle specie afidifaghe nella lotta biologica conservativa

Scopo della presente ricerca era quello di approfondire il ruolo dei Sirfidi afidifagi ponendo particolare attenzione alle interazioni multitrofiche e all'effetto del paesaggio sul popolamento di Sirfidi. Larve e pupe di Sirfidi sono state monitorate in siti a diverso impatto antropico, in particolare in monocolture di mais e frumento ed in aree a maggiore diversità. La percentuale di parassitizzazione è risultata significativamente maggiore in aree a maggiore semplificazione, in particolare nei campi di mais. Anche la tipologia dei parassitoidi di Sirfidi è risultata diversa: mentre Pachyneuron (Encyrtidae) è il parassitoide chiave nel mais, in altri siti i Diplazontini (Ichneumonidae) sono risultati più frequenti. La distribuzione spaziale di Sirfidi ed altri predatori/parassitoidi afidifagi è stata analizzata in campi di mais e frumento dal 2007 al 2009. I pattern di distribuzione spaziale e temporale sembrano tali da impedire la sovrapposizione degli afidifagi favorendo una partizione di nicchia. Il popolamento di Sirfidi in un'area rurale caratterizzata da forte ricchezza in elementi di naturalità è stata analizzata per tre anni consecutivi, permettendo il ritrovamento di specie molto rare come Criorhina pachymera. Ai dati ottenuti è stato applicato Syrph the Net per la valutazione dello stato di conservazione del sito; è stata riscontrata una percentuale elevata di specie osservate ma non attese confermando come questo parametro può essere molto utile nella valutazione del paesaggio soprattutto in ambienti rurali. Infine Syrph the Net è stato applicato al popolamento di Sirfidi della provincia di Ferrara confermando l'utilità di questa tecnica per la valutazione della conservazione degli habitat anche in comprensori molto ampi