Herbivory on the pedunculate oak along an urbanization gradient in Europe : Effects of impervious surface, local tree cover, and insect feeding guild

Urbanization is an important driver of the diversity and abundance of tree-associated insect herbivores, but its consequences for insect herbivory are poorly understood. A likely source of variability among studies is the insufficient consideration of intraurban variability in forest cover. With the help of citizen scientists, we investigated the independent and interactive effects of local canopy cover and percentage of impervious surface on insect herbivory in the pedunculate oak (Quercus robur L.) throughout most of its geographic range in Europe. We found that the damage caused by chewing insect herbivores as well as the incidence of leaf-mining and gall-inducing herbivores consistently decreased with increasing impervious surface around focal oaks. Herbivory by chewing herbivores increased with increasing forest cover, regardless of impervious surface. In contrast, an increase in local canopy cover buffered the negative effect of impervious surface on leaf miners and strengthened its effect on gall inducers. These results show that – just like in non-urban areas – plant-herbivore interactions in cities are structured by a complex set of interacting factors. This highlights that local habitat characteristics within cities have the potential to attenuate or modify the effect of impervious surfaces on biotic interactions.Agence Nationale de la Recherche, Grant/Award Number: ANR-10--LABX-45; Fondation BNP Paribas.info:eu-repo/semantics/publishedVersio

Herbivory on the pedunculate oak along an urbanization gradient in Europe : Effects of impervious surface, local tree cover, and insect feeding guild

Urbanization is an important driver of the diversity and abundance of tree-associated insect herbivores, but its consequences for insect herbivory are poorly understood. A likely source of variability among studies is the insufficient consideration of intra-urban variability in forest cover. With the help of citizen scientists, we investigated the independent and interactive effects of local canopy cover and percentage of impervious surface on insect herbivory in the pedunculate oak (Quercus robur L.) throughout most of its geographic range in Europe. We found that the damage caused by chewing insect herbivores as well as the incidence of leaf-mining and gall-inducing herbivores consistently decreased with increasing impervious surface around focal oaks. Herbivory by chewing herbivores increased with increasing forest cover, regardless of impervious surface. In contrast, an increase in local canopy cover buffered the negative effect of impervious surface on leaf miners and strengthened its effect on gall inducers. These results show that-just like in non-urban areas-plant-herbivore interactions in cities are structured by a complex set of interacting factors. This highlights that local habitat characteristics within cities have the potential to attenuate or modify the effect of impervious surfaces on biotic interactions.Peer reviewe

Herbivory on the pedunculate oak along an urbanization gradient in Europe: Effects of impervious surface, local tree cover, and insect feeding guild

Urbanization is an important driver of the diversity and abundance of tree-associated insect herbivores, but its consequences for insect herbivory are poorly understood. A likely source of variability among studies is the insufficient consideration of intra-urban variability in forest cover. With the help of citizen scientists, we investigated the independent and interactive effects of local canopy cover and percentage of impervious surface on insect herbivory in the pedunculate oak (Quercus robur L.) throughout most of its geographic range in Europe. We found that the damage caused by chewing insect herbivores as well as the incidence of leaf-mining and gall-inducing herbivores consistently decreased with increasing impervious surface around focal oaks. Herbivory by chewing herbivores increased with increasing forest cover, regardless of impervious surface. In contrast, an increase in local canopy cover buffered the negative effect of impervious surface on leaf miners and strengthened its effect on gall inducers. These results show that-just like in non-urban areas-plant-herbivore interactions in cities are structured by a complex set of interacting factors. This highlights that local habitat characteristics within cities have the potential to attenuate or modify the effect of impervious surfaces on biotic interactions

A review of bioanalytical techniques for evaluation of cannabis (Marijuana, weed, Hashish) in human hair

Cannabis products (marijuana, weed, hashish) are among the most widely abused psychoactive drugs in the world, due to their euphorigenic and anxiolytic properties. Recently, hair analysis is of great interest in analytical, clinical, and forensic sciences due to its non-invasiveness, negligible risk of infection and tampering, facile storage, and a wider window of detection. Hair analysis is now widely accepted as evidence in courts around the world. Hair analysis is very feasible to complement saliva, blood tests, and urinalysis. In this review, we have focused on state of the art in hair analysis of cannabis with particular attention to hair sample preparation for cannabis analysis involving pulverization, extraction and screening techniques followed by confirmatory tests (e.g., GC–MS and LC–MS/MS). We have reviewed the literature for the past 10 years’ period with special emphasis on cannabis quantification using mass spectrometry. The pros and cons of all the published methods have also been discussed along with the prospective future of cannabis analysis

Winter bird numerical responses to a key defoliator in mountain pine forests

Please help populate SUNScholar with the full text of SU research output. Also - should you need this item urgently, please send us the details and we will try to get hold of the full text as quick possible. E-mail to [email protected]. Thank you.Journal Articles (subsidised)AgriwetenskappeBewaringsekologie en Entomologi

Extended Simulated Distillation by Capillary Supercritical Fluid Chromatography

Simulated distillation (simdist) based on separation using gas chromatography (GC) is widely spread in the petroleum industry for evaluation of fossil fuels as well as petroleum feeds and cuts produced by refining and conversion processes. Through a calibration curve relating the boiling point of normal paraffins to their elution temperature or retention time, simdist provides the hydrocarbon distribution of the sample (in weight percent) versus the boiling range of the fraction. The operating conditions used for simdist are tuned to be in agreement with preparative distillation that gives the True Boiling Point (TBP) curve. However, this technique is not compatible to heavy ends (FBP higher than 700°C) due to the limitation of volatility of the products and the lack of resistance of high molecular-weight hydrocarbons to cracking reactions. The interest of supercritical-fluid chromatography (SFC) is that high temperatures are not needed to elute heavy ends and that the mechanism for extending the upper limit of simdist depends only on sample solubility into the supercritical mobile phase. This paper presents recent advances in Simdist using SFC of heavy fractions. Compared to GC, SFC extends the range of this application up to nC126 hydrocarbons and makes possible to calibrate up to nC200. Thus, SFC could be the tool of choice for better determination of conversion in heavy petroleum-fraction processing

Typologie des auréoles bocageres en milieu rural. Cas d'étude de la Commaunauté de Communes de Bapaume

La communauté de communes de la région de Bapaume (CCRB) a réalisé un état des lieux de son territoire pour définir les grandes orientations d'aménagement. L'étude intègre les auréoles bocagères à l'interface des zones urbanisées et du milieu agricole, reconnues comme dépendantes des dynamiques agricoles locales. Pour ce faire, il est nécessaire de réaliser des diagnostics des territoires, intégrant les éléments semi-naturels, et par-là même de définir des typologies. L'étude s'est intéressée à la comparaison de deux méthodes pour la réalisation des typologies : à dire d'experts et statistique. Les typologies des auréoles bocagères ont montré que les communes avec des auréoles dégradées sont majoritaires. Leur état de conservation n'a pu être corrélé ni avec les orientations technico-économiques ou les typologies des communes ni avec la présence d'infrastructures routières. L'étude démontre l'importance de la prise en compte historique du territoire et l'insuffisance de la méthode statistique qui ne traduit pas assez finement l'impression paysagère locale