Niche engineering reveals complementary resource use

Abstract

Abstract. Greater resource use by diverse communities might result from species occupying complementary niches. Demonstrating niche complementarity among species is challenging, however, due to the difficulty in relating differences between species in particular traits to their use of complementary resources. Here, we overcame this obstacle by exploiting plastic foraging behavior in a community of predatory insects common on Brassica oleracea plants in Washington, USA. These predators complemented one another by partitioning foraging space, with some species foraging primarily along leaf edges and others at leaf centers. We hypothesized that emergent biodiversity effects would occur when predators partitioned foraging space on leaves, but not when spatial complementarity was dampened. Indeed, on intact leaves, edge-and center-foraging predators combined to kill more prey than any single predator species could by itself. These emergent diversity effects, however, disappeared on plants damaged by the caterpillar Plutella xylostella. Caterpillar chew-holes brought edge habitats to the center of leaves, so that all predator species could attack aphids anywhere on plants. With spatial niche differences diminished, there were no benefits of predator diversity; the most voracious single predator species killed the most aphids. Thus, caterpillar herbivory determined whether multi-predator-species effects reflected complementarity or species' individual impacts. Our study provides direct evidence for a causative relationship between niche differentiation and increased resource consumption by diverse communities, as revealed by ecological engineers that homogenize the foraging environment.

Functional diversity positively affects prey suppression by invertebrate predators: a meta‐analysis

“…2010, Gable et al. 2012). Consequently, our metric of diet breadth may have captured more subtle separation in predator feeding locations between specialist and generalists that were not captured by broader distinction within the habitat domain category.…”

Effects of grazer diversity on marine microphytobenthic biofilm: a ‘tug of war’ between complementarity and competition

“…In general, these experiments indicated that more diverse communities exhibited high productivity and a more efficient resource use compared to less diverse communities (Hooper et al 2005). Later, BEF experiments were extended to other communities and their complexity has increased to better discriminate the effects of individual species (identity effects) from the effects of partitioning in resource use among species (complementarity) (Gable et al 2012). Novel aspects of BEF research have also involved the analysis of realistic non-random species losses (Bracken et al 2008) and the exploration of trophic interactions (Aquilino & Stachowicz 2012).…”

The identity of belowground herbivores, not herbivore diversity, mediates impacts on plant productivity

“…Previous work in predator-prey systems, for example, has shown that the diversity of the resource base can have considerable impacts on the biodiversity-ecosystem functioning relationship. In a system with predators feeding on aphids on collard plants, for example, coccinellid beetles forage on leaf edges while parasitoid wasps forage on leaf centers, leading to spatial complementarity and a positive relationship between predator diversity and aphid consumption10. However, when caterpillars are introduced to the system this complementarity is reduced because caterpillars chew holes in leaf centers (creating edges for coccinellids), and species identity effects become prevalent due to increased niche overlap between predators10.…”

“…Another approach is to directly manipulate niche complementarity among consumers, and experimentally determine if greater complementarity promotes resource consumption910. Both of these approaches, however, require complex experimental designs that are often not practical for many systems.…”

“…Few studies have focused on interactions between herbivore diversity and plant productivity in terrestrial ecosystems. Thus, whether patterns of diversity strengthening resource consumption seen in predator-prey123456789101112 and aquatic13141516 systems, and the underlying mechanisms, hold for terrestrial herbivore-plant systems remains largely unknown.…”