Nonadditive effects of consumption in an intertidal macroinvertebrate community are independent of food availability but driven by complementarity effects. Issue 6 (16th February 2018)

• Record Type: Journal Article
• Authors: van Egmond, Emily M.; van Bodegom, Peter M.; van Hal, Jurgen R.; van Logtestijn, Richard S. P.; Berg, Matty P.; Aerts, Rien
• Is Part Of: Ecology and evolution. Volume 8:Issue 6(2018)
• Page Start: 3086
• Page End: 3097
• Publication Date: 2018-02-16
• Subjects: benthos -- community assembly -- functional diversity -- soft‐sediment beach -- trophic interactions; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.3841
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Suboptimal environmental conditions are ubiquitous in nature and commonly drive the outcome of biological interactions in community processes. Despite the importance of biological interactions for community processes, knowledge on how species interactions are affected by a limiting resource, for example, low food availability, remains limited. Here, we tested whether variation in food supply causes nonadditive consumption patterns, using the macroinvertebrate community of intertidal sandy beaches as a model system. We quantified isotopically labeled diatom consumption by three macroinvertebrate species ( Bathyporeia pilosa, Haustorius arenarius, and Scolelepis squamata ) kept in mesocosms in either monoculture or a three‐species community at a range of diatom densities. Our results show that B. pilosa was the most successful competitor in terms of consumption at both high and low diatom density, while H. arenarius and especially S. squamata consumed less in a community than in their respective monocultures. Nonadditive effects on consumption in this macroinvertebrate community were present and larger than mere additive effects, and similar across diatom densities. The underlying species interactions, however, did change with diatom density. Complementarity effects related to niche‐partitioning were the main driver of the net diversity effect on consumption, with a slightly increasing contribution of selection effects related to competition with decreasing diatom density. For the first time, we showed that nonadditive effects of consumption are independent of food availability in a macroinvertebrate community. This suggests that, in communities with functionally different, and thus complementary, species, nonadditive effects can arise even when food availability is low. Hence, at a range of environmental conditions, species interactions hold important potential to alter ecosystem functioning. Abstract : To test whether variation in food supply causes nonadditive consumption patterns, we quantified isotopically labeled diatom consumption by three intertidal macroinvertebrate species kept in mesocosms in either monoculture or a community at a range of diatom densities. Complementarity effects on consumption were the main driver of the net diversity effect, with a slightly increasing contribution of selection effects with decreasing diatom density. For the first time, we have shown that nonadditive effects of consumption are independent from food availability in a macroinvertebrate community.