PARENT SESSION
Poster Session 19: Biodiversity
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Herbivores at multiple scales alter plant diversity differentially.
De Deyn, Gerlinde*,1, 2, Raaijmakers, Ciska2, van Ruijven, Jasper3, Berendse, Frank4, van der Putten, Wim2, 4, 1 University of Guelph, Guelph, Ontario2 Netherlands Institute of Ecology, Heteren, Netherlands3 Silwood Park, Ascot, U.K.4 Wageningen University and Research Centre, Wageningen, Netherlands
ABSTRACT- Plant diversity is an important component of ecosystems for maintenance of ecosystem properties like primary productivity. In terrestrial ecosystems primary producers interact with heterotrophic organisms at both sides of the soil surface. Above- and belowground organisms, however, interact with plants at different spatial and temporal scales. Spatial scale differences of the interactions relate to constraints on mobility and size, while temporal scale differences arise from differential dynamics of plant shoot and root physiology. In this paper we show that herbivores acting at larger scale aboveground interact with small, shorter ranged, organisms belowground, thereby affecting each others abundance and plant community diversity. We present data from an outdoor mesocosm study in which we introduced grasshoppers, wireworms or nematodes in a full-factorial way in plant communities assembled from 16 species. Plant community biomass and diversity as well as nematode community composition were recorded over two growing seasons. All invertebrate groups affected plant diversity but in a differential and non-additive way. Changes in the plant community seemed to be carried over to the soil food web, in particular to plant- and bacterial feeders. Grasshoppers reduced the numbers of all nematodes by reducing the numbers of bacterial-feeders. Wireworms, on the other hand, stimulated the numbers of all nematodes mainly through increasing plant-feeding nematode abundance, in particular the forb-feeding specialist Meloidogyne hapla. We propose that on the longer term local plant community dynamics may be altered by local changes in the soil food-web, due to interactions with herbivores operating at larger spatial scale.
Key words: above- belowground interactions, plant diversity, non-additive effects, soil nematode community