STN keys for the identification of adult european syrphidae 2012

The identification keys presented here include a key to the genera of European Syrphidae and Microdontidae and keys to the species of various genera. They do not comprise a comprehensive set of keys to the identification of European syrphid species. While every effort has been made to ensure that each key is as self-contained and accurate as possible it is not suggested that these keys be used in isolation from other literature on identification of European syrphids. In the StN Species Accounts volume (Speight, 2012) information is given for each species on identification literature, sources of figures of the male terminalia, sources of coloured illustrations of the adult fly etc., together with suggestions (where appropriate) of additional features to use for identification purposes. That information is not repeated here. A genus for which an StN key to the European species exists is indicated in the generic key following the name of the genus, by the phrase “see StN key to European species”. Various syrphid genera are represented in Europe by no more than one species. For these, the generic key provides a mechanism for identification to species level and the name of the European species is given in the generic key, following the name of the genus. This volume is presented in two sections, an English section and a French section. The key to European syrphid genera appears only in the English section. But all of the keys to the species of individual genera appear in both sections. Each key is dated, to show when it was most recently updated. The keys to the species of individual genera are presented in alphabetical order of the genera they cover, under Microdontidae and Syrphidae. No grouping is made of genera in subfamilies or tribes. For further information on the known European species in each genus the StN Species Accounts volume (Speight, 2012) should be consulted. There is unfortunately no standard set of English-language terms used for morphological features in taxonomic literature on Syrphidae. Contrasting accounts are provided by Thompson (1999) and Speight (1987). Part 3 of the present volume presents a Glossary of the terms used for morphological features in the StN keys, together with figures showing those features

Paysages agricoles et biodiversité : Apports de la modélisation fonctionnelle appliquée aux Diptères Syrphidés

Apports de la modélisation fonctionnelle appliquée aux Diptères Syrphidés

Chapitre 2 - Les services écosystémiques rendus par les sols du point de vue de l’agronomie : le cas de l'agriculture de conservation

Les agroécosystèmes sont des espaces d’interface entre l’homme, ses pratiques et son savoir-faire, et les ressources naturelles. Contrairement aux écosystèmes naturels, les agroécosystèmes ont une orientation productive marquée, et l’homme influe sciemment sur leurs paramètres biologiques et physico-chimiques dans le but d’assurer quantitativement et qualitativement la production agricole via notamment l’irrigation, la fertilisation et le contrôle des bioag..

Towards a cost-effectiveness analysis of the measurement of biodiversity indicators

A comprehensive quantification of biodiversity in farming systems would require a very significant amount of work (and funds) even for a small area. Therefore, biodiversity indicators are needed to solve the problem of the measurement feasibility. Even though the issue of cost and effectiveness is central for the evaluation of the indicators, only the latter is discussed in detail in the scientific literature. This work presents a cost analysis based on the direct gathering of records from a farm-scale biodiversity survey (EU-FP7, BioBio - “Indicators for biodiversity in organic and low-input farming systems”) where the analysis of costs is part of the project. It is a simple method for comparing different indicators by their ratio of cost/effectiveness. Here we present the results from the French case study (Gascony Hills, Midi-Pyrenees Region)

Biodiversité et services rendus à l’agriculture. Principaux enseignements de différents dispositifs de recherche récents et actuels en Midi-Pyrénées

Dans le canton d’Aurignac, des chercheurs de l’Institut national de la recherche agronomique et de l’Institut national polytechnique de Toulouse travaillent depuis une trentaine d’années sur l’agriculture, les paysages et la biodiversité. Les paysages agricoles étudiés sont caractérisés par une agriculture de polyculture élevage et la présence de petits bois. Ces paysages agri-forestiers constituent un site d’étude à long terme qui est reconnu au niveau national et européen

Hoverfly (diptera: syrphidae) richness and abundance vary with forest stand heterogeneity: preliminary evidence from a case study in a montane beech fir forest

Hoverflies (Diptera: Syrphidae) provide crucial ecological services and are increasingly used as bioindicators in environ- mental assessment studies. Information is available for a wide range of life history traits at the species level for most Syrphidae but little is recorded about the environmental requirements of forest hoverflies at the stand scale. The aim of this study was to explore whether the structural heterogeneity of a stand influences species richness or abundance of hoverflies in a montane beech-fir forest. We used the catches of Malaise traps set in 2004 and 2007 in three stands in the French Pyrenees, selected to represent a wide range of structural heterogeneity in terms of their vertical structure, tree diversity, deadwood and tree-microhabitats. We assessed hoverfly assemblages by recording species richness, abundance and functional diversity. Malaise traps caught 2,374 hoverflies belonging to 104 species. The catches of hoverflies fluctuated both in species richness and abundance between 2004 and 2007. Strictly forest species were only caught in the most heterogeneous stand. Species strictly associated with fir were not recorded in the least heterogeneous stand although fir was present. Although most of the functional groups were recorded in the three stands, species richness, abundance and functional diversity decreased dramatically from the most heterogeneous to the least heterogeneous stand. However, the species assemblages in the less heterogeneous stands were not perfect subsets of that in the most heterogeneous stand, as some additional species not found in the most heterogeneous stand were also present

Les diptères syrphides face aux critères de sélection des bioindicateurs terrestres

La biologie de la conservation est un thème émergent des sciences de la biodiversité. Ce thème confronte les approches de l'écologie des populations et des communautés, des sciences économiques, de l'éthique, du droit et de la gestion de l'environnement autour des problèmes de préservation de la biodiversité. Une conception biologique de la conservation implique que les politiques de gestion du milieu naturel soient attentives au maintien du potentiel évolutif du vivant en créant les conditions de viabilité des populations et d'entretien de leur diversité génétique. Elles doivent aussi veiller au maintien de la richesse spécifique et de la diversité biologique et fonctionnelle des communautés. De telles politiques de gestion relèvent du concept de développement durable qui associe sciences économiques et juridiques pour définir des modes de développement respectueux de la qualité de l'environnement. La biodiversité représente à cet égard à la fois un indicateur et un enjeu pour la persistance de ressources potentielles et le maintien de la fonctionnalité des écosystèmes. Si ce champ interdisciplinaire est bien développé outre-atlantique, son émergence est plus récente en Europe, et plus particulièrement dans les régions francophones. Néanmoins de nombreuses opérations de conservation biologique réalisées dans ces régions sont accompagnées de programmes de recherche comme en atteste la multiplication des thèses de doctorats soutenues dans ce domaine. Le développement de ce champ interdisciplinaire a motivé l'idée d'organiser une réunion qui donnerait aux chercheurs impliqués dans ces thèmes émergents la possibilité de présenter leurs travaux. Les gestionnaires d'espaces naturels ou les administrations en charge de la préservation de la biodiversité pourraient trouver dans cette réunion une opportunité d'exprimer et de confronter leurs attentes aux derniers progrès méthodologiques et conceptuels. Ce colloque a permis de faire le point sur la discipline dans les contrées francophones et de faire le lien entre la communauté francophone et la section européenne de la Society for Conservation Biology

Assessing the costs of measuring biodiversity: methodological and empirical issues

Organic and low-input farming practices are considered keystones for the conservation of biodiversity in semi-natural systems. Accordingly, attention to the assessment of the benefits stemming from these activities is increasing in order to provide a solid base for the adoption of agro-environmental incentives and to support their monitoring and evaluation. The evaluation of the positive effects of organic and low-input farming activities on biodiversity is limited mainly by: the difficulty in proposing simple and widely-applicable indicators of biodiversity, and the substantial lack of data concerning the costs of measuring biodiversity - an essential element for a cost-effectiveness analysis. Moreover, the limited scientific literature available is based on ex-post analysis rather than on systematic data collection. The assessment of the costs of measuring biodiversity at farm-scale throughout Europe is one of the specific tasks of the BioBio project (UE-FP7). In this work, we discuss methodological aspects and preliminary results based on data gathered during fieldwork measurements of biodiversity in BioBio

The effect of semi-natural habitats on aphids and their natural enemies across spatial and temporal scales

Semi-natural habitats in agricultural landscapes are generally assumed to enhance the biological control of insect pests based on native beneficial insects, by providing alternative prey and hosts, resources and refuges for overwintering. We hypothesized that natural enemies of winter wheat aphids should arrive sooner in fields near semi-natural habitats. We compared aphid, hoverfly (larvae and eggs) and parasitized aphid (mummies) abundances in 54 winter wheat fields located in southern France from 2003 to 2007. Six surveys were recorded each spring and were split into the early period (defined as the period before the peak of aphid growth) and the late period (after the peak). The wheat fields differed by their surrounding landscape composition measured as the proportion of semi-natural habitats (woods, hedges and grasslands), at three different spatial scales: 200 m, 500 m, and 1200 m. Despite great variability in abundance data between years, the abundance of hoverflies appeared more sensitive to landscape composition than aphid abundance was. Early abundance for both aphids and hoverflies was positively related to wood cover, but not late abundance in spring. The abundance of hoverflies was positively related to hedge and grassland cover at all spatial scales and both periods considered. Aphid parasitism was higher near hedges at the small spatial scale late in the spring. Our results confirmed that higher proportions of semi-natural habitats in agricultural landscapes enhance the biological control of pests, but this effect depends on the spatial scale, the time period in the spring and the natural enemies considered

Is there a synergy between hedges and intercrops for pest biocontrol ?

A major challenge for agroecology is to identify alternative cropping systems that can both ensure sufficient levels of food production and reduction in pesticide inputs while maintaining ecosystem integrity and simultaneously delivering multiple ecosystem services. Among ecological services, biocontrol of pests by natural enemies could be improved by effective management of semi-natural elements in landscape such as hedgerows (Landis et al., 2000). Another way to reduce pest populations in fields consists in increasing diversity of crop species both in time and space. A practice such as intercropping that creates structures of mixed plant populations with "barrier" or "dilution of resources" effects (Médiène et al., 2011) can reduce the pressure of pathogens, weeds and pests compared with that exerted on sole crops (Letourneau et al., 2011). While the combination of these two kinds of practices designed to strengthen auxiliary communities often appears efficient and could result in a synergy, many cases of study show opposite results (e.g. Straub and Snyder, 2006). Our study aimed at quantifying and comparing the efficiency of both hedgerow and intercropped pea and wheat on pest biocontrol in a field. We examined i) the potential role of different types of field edges (with and without an hedgerow) on biological control of weed seeds, aphids, pea weavils and eggs of Sitona lineatus, ii) the effect of intercropping on the biological control of these pests compared with sole crops and iii) the interaction between the two factors. We conducted both field surveys of pest abundance and pest biocontrol effectiveness by estimating predation rates by using seeds and prey sticked on cards. We found that aphid density was slightly lower in pea-wheat intercrops than in sole crops, and was influenced by the distance from the field edge (whatever the kind of edges). However, neither the hedgerow nor the intercrop situation favored aphid predation. The density of weeds did not vary according to the cropping system and distance from the field edge. We showed that the predation rate of weed seeds or of Sitona lineatus eggs and the parasitism of Bruchus pisorum decreased according to the distance to the hedge in sole crops but increased in the intercrop. This study points out the absence of a global synergy between intercrops and hedges in supporting pest and weed regulation: the regulation efficiency varied according to pest species. This study calls for a deepened multi-species approach in order to find trade-offs between agricultural practices and field edge management to optimize regulating ecosystem services such as pest biocontrol