Impacts of a pesticide on pollinator species richness at different spatial scales

• Published in: Basic and applied ecology 2010-03, Vol.11 (2), p.106-115
• Main Authors: Brittain, C.A., Vighi, M., Bommarco, R., Settele, J., Potts, S.G.
• Format: Article
• Language: English
• Subjects: Agricultural chemicals; Agriculture; Agro-chemicals; Apoidea; Bees; Bombus; Bumblebees; Butterflies; Farms; Fenitrothion; insect ecology; Insecticide; Insecticides; landscape ecology; nontarget organisms; Pesticides; pollinating insects; Sampling; species diversity
• ISSN: 1439-1791
• DOI: 10.1016/j.baae.2009.11.007

Pesticides are an important potential cause of biodiversity and pollinator decline. Little is known about the impacts of pesticides on wild pollinators in the field. Insect pollinators were sampled in an agricultural system in Italy with the aim of detecting the impacts of pesticide use. The insecticide fenitrothion was over 150 times greater in toxicity than other pesticides used in the area, so sampling was set up around its application. Species richness of wild bees, bumblebees and butterflies were sampled at three spatial scales to assess responses to pesticide application: (i) the ‘field’ scale along pesticide drift gradients; (ii) the ‘landscape’ scale sampling in different crops within the area and (iii) the ‘regional’ scale comparing two river basins with contrasting agricultural intensity. At the field scale, the interaction between the application regime of the insecticide and the point in the season was important for species richness. Wild bee species richness appeared to be unaffected by one insecticide application, but declined after two and three applications. At the landscape scale, the species richness of wild bees declined in vine fields where the insecticide was applied, but did not decline in maize or uncultivated fields. At the regional scale, lower bumblebee and butterfly species richness was found in the more intensively farmed basin with higher pesticide loads. Our results suggest that wild bees are an insect pollinator group at particular risk from pesticide use. Further investigation is needed on how the type, quantity and timing of pesticide application impacts pollinators. Pestizide stellen einen möglichen Grund für die Diversitäts- und Bestäuberabnahme dar. Es ist jedoch wenig über die Wirkung von Pestiziden auf wildlebende Bestäuber im Freiland bekannt. Mit dem Ziel die Auswirkungen von Pestizideinsätzen festzustellen wurden Bestäuberinsekten in einem landwirtschaflichen Systemen in Italien gesammelt. Das Insektizid Fenitrothion ist etwa 150 mal toxischer als die anderen Pestizide, die in der Gegend genutzt werden, und so wurde die Untersuchung rund um seine Nutzung angelegt. Um die Reaktionen auf die Pestizidanwendung abzuschätzen wurde der Artenreichtum der Wildbienen, Hummeln und Schmetterlinge auf drei räumlichen Skalen untersucht: (i) auf der Feldskala entlang von Gradienten der Pestiziddrift, (ii) auf der Landschaftsskala indem verschiedene Feldfrüchte in dem Gebiet beprobt wurden und (iii) auf der regionalen Skala indem