Ecosystem engineering and predation: the multi-trophic impact of two ant species.

摘要: Summary 1. Ants are ubiquitous ecosystem engineers and generalist predators able to affect ecological communities via both pathways. They likely influence any other terrestrial arthropod group either directly or indirectly caused by their high abundance territoriality. 2. We studied the impact of two ant species common in Central Europe, Myrmica rubra Lasius niger, on an community. Colony presence density these were manipulated a field experiment from start activity spring late summer. 3. The revealed positive one colony densities decomposers, herbivores parasitoids. However, case parasitoids, this effect was reversed colonies. 4. Generally, effects similar with exception Braconidae parasitoid that responded positively M. rubra but not L. niger. 5. Spider affected manipulation, richness spiders presence. This independent density, where colonies present, spider significantly greater plots than each species. 6. To test whether engineering purely modified properties soil, we added additional (i) soil nests (without ants) (ii) unmodified (iii) (including experimental plots. Ant nest its own did have significant predators, which significantly, positively, addition intact nest. 7. The results suggest important role grassland food web, strongly affecting higher trophic levels. We discuss how relative bottom-up top-down ants depends relatively predatory at densities.