title: Trapping the Pasture Odorscape Using Open-Air Solid-Phase Micro Extraction, a Tool to Assess Grassland Value.
abstract: Besides supporting cattle feeding, grasslands are home to a diversity of plants and insects that interact with each other by emitting volatile compounds. The aim of this work was to develop a method to determine permanent grassland odorscape and relate it to flower-visiting insects. Two grasslands were chosen for their contrasting levels of botanical diversity, resulting from differing grazing managements. Measurements were made over two periods of three consecutive days at the beginning of grazing, and just after the cows had left the plots. Volatile compounds were trapped using solid-phase microextraction (SPME) fibers exposed eight hours a day in three exclosures per plot, and then analyzed by gas-chromatography-mass spectrometry (GC-MS). Insects were trapped using pan traps and a net, sorted and counted. The open air SPME method yielded volatile compound profiles that were richer than maize field profiles, comprising the common green leaf volatiles (GLV) and more specific ones. Differences between the odorscapes of the two grasslands were found, but they were not as marked as expected from their botanical composition. By contrast, there were sharp differences between the two periods, resulting from the combined effects of changes in weather conditions, plant phenological stage and grazing progress. Several correlations between insect counts and volatile compounds were found. Although their correlation coefficients were low, some of them were confirmed when tested by Spearman rank correlation, and could be logically explained. This method of grassland odorscape deserves to be developed because it can provide information on many aspects of grassland function and on the stresses that grassland plants undergo.
authors.affiliation: UMR1213 Herbivores, INRA-VetAgro Sup-Clermont Université, Saint-Genès Champanelle, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Cornu
authors.affiliation: UMR1213 Herbivores, INRA-VetAgro Sup-Clermont Université, Saint-Genès Champanelle, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Farruggia
authors.affiliation: UMR1392 Institut d'Ecologie et des Sciences de l'Environnement de Paris, INRA, Versailles, France.
authors.forename: Ene
authors.initials: E
authors.lastname: Leppik
authors.affiliation: UMR1392 Institut d'Ecologie et des Sciences de l'Environnement de Paris, INRA, Versailles, France.
authors.forename: Centina
authors.initials: C
authors.lastname: Pinier
authors.affiliation: UE1296 Unité Expérimentale des Monts d'Auvergne, INRA, Laqueuille, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Fournier
authors.affiliation: Diagnostic Gestion Environnement, Arzens, France.|Observatoire des Abeilles, Arzens, France.
authors.forename: David
authors.initials: D
authors.lastname: Genoud
authors.affiliation: UMR1392 Institut d'Ecologie et des Sciences de l'Environnement de Paris, INRA, Versailles, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Frérot
mesh_terms: D000818:Animals; D002417:Cattle; D008401:Gas Chromatography-Mass Spectrometry; D065948:Grassland; D007313:Insecta / Q000145:classification*; D009812:Odorants / Q000032:analysis*; D052638:Particulate Matter / Q000032:analysis*; D010944:Plants / Q000145:classification*; D052617:Solid Phase Microextraction; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D052638:Particulate Matter; D055549:Volatile Organic Compounds