Entomologia Experimentalis et Applicata (2013) 147, 269-281

Christine Herbst, Nicole Wäschke, E. Kathryn Barto, Sabrina Arnold, Daniel Geuß, Ivonne Halboth, Sabina Reschke, Jakob Sänger, Torsten Meiners and Elisabeth Obermaier (2013)
Land use intensification in grasslands: higher trophic levels are more negatively affected than lower trophic levels
Entomologia Experimentalis et Applicata 147 (3), 269-281
Abstract: Increasing land use intensity and human influence are leading to a reduction in plant and animal species diversity. However, little is known about how these changes may affect higher trophic levels, apart from simply reducing species numbers. Here we investigated, over 3 years, the influence of different land practices on a tritrophic system in grassland habitats. The system consisted of the host plant Plantago lanceolata L. (Plantaginaceae), two monophagous weevils, Mecinus labilis Herbst and Mecinus pascuorum Gyllenhal (Coleoptera: Curculionidae), and their parasitoid Mesopolobus incultus Walker (Hymenoptera: Pteromalidae). At over 70 sites across three geographic regions in Germany, we measured plant species diversity and vegetation structure, as well as abundance of P. lanceolata, the two weevils, and the parasitoid. Land use intensity (fertilization) and type (mowing vs. grazing) negatively affected not only plant species richness but also the occurrence of the two specialized herbivores and their parasitoid. In contrast, land use had a mostly positive effect on host plant size, vegetation structure, and parasitization rate. This study reveals that intensification of land use influences higher trophic organisms even without affecting the availability of the host plant. The observed relationships between land use, vegetation complexity, and the tritrophic system are not restricted locally; rather they are measureable along a broad range of environmental conditions and years throughout Germany. Our findings may have important implications for the conservation of insect species of nutrient-poor grasslands.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Torsten Meiners, Elisabeth Obermaier

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Plantago lanceolata (weed)		Germany
Mecinus labilis (weed bioagent)	Plantago lanceolata (weed)		Germany
Mecinus pascuorum (weed bioagent)	Plantago lanceolata (weed)		Germany