Ontogenetic diet shifts promote predator‐mediated coexistence

Abstract

Ontogenetic diet shifts promote predator-mediated coexistenceWollrab, S.; de Roos, A.M.; Diehl, S. Published in: Ecology DOI:10.1890/12-1490.1 Link to publication Citation for published version (APA):Wollrab, S., de Roos, A. M., & Diehl, S. (2013). Ontogenetic diet shifts promote predator-mediated coexistence. Ecology, 94(12), 2886-2897. DOI: 10.1890/12-1490.1 General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Abstract. It is widely believed that predation moderates interspecific competition and promotes prey diversity. Still, in models of two prey sharing a resource and a predator, predator-mediated coexistence occurs only over narrow ranges of resource productivity. These models have so far ignored the widespread feature of ontogenetic diet shifts in predators. Here, we theoretically explore the consequences of a diet shift from juvenile to adult predator stages for coexistence of two competing prey. We find that only very minor deviations from perfectly identical diets in juveniles and adults destroy the ''traditional'' mechanism of predatormediated coexistence, which requires an intrinsic trade-off between prey defendedness and competitive ability. Instead, predator population structure can create an ''emergent'' competition-predation trade-off between prey, where a bottleneck in one predator stage enhances predation on the superior competitor and relaxes predation on the inferior competitor, irrespective of the latter's intrinsic defendedness. Pronounced diet shifts therefore greatly enlarge the range of prey coexistence along a resource gradient. With diet shifts, however, coexistence usually occurs as one of two alternative states and, once lost, may not be easily restored.

Ontogenetic Shifts in the Predatory Habits of the Northern Moonsnail (Lunatia heros) on the Northwestern Atlantic Coast

“…Efforts should now be made to confirm or refute this by examining the size and mode of feeding of newly settled juveniles of L. heros directly under laboratory and field conditions. Understanding how prey preference and diet change across a predatorÕs life span, from newly metamorphosed juvenile to adult, is essential to understanding community-wide effects of predators in various systems (Wollrab et al 2013). Muricid gastropods can shift between preferred prey species depending on prey abundance, and will remain selecting the latter prey species even if the former rebounds and becomes abundant again (e.g., Wood 1968, Murdoch 1969.…”

“…Using theoretical models, Wollrab et al (2013) showed that small changes in diet between juvenile and adult predators can shift mechanisms of predator-mediated coexistence among predators and prey within an ecological community. Although these shifts can potentially promote coexistence and biodiversity, they can also introduce alternative states within ecological communities, in which slight disturbances can lead to depauperate communities (Wollrab et al 2013). Without the knowledge of dietary changes across the ontogeny of naticid gastropods, assessments of whole-community impacts of naticid predation have to assume uniform predatory behavior across all sizes and ages of these predators.…”

Continental-scale variability in the feeding ecology of juvenile Chinook salmon along the coastal Northeast Pacific Ocean

“…These ontogenetic niche shifts may have widespread effects on population and community dynamics (de Roos & Persson 2013), such as promoting the coexistence of competitors (Wollrab et al 2013), reducing the stabilizing effects of ecosystem complexity (Rudolf & Lafferty 2011), and even altering the strength of trophic cascades (Rudolf & Rasmussen 2013). Variations in trophic interactions as a result of ontogenetic niche shifts are beginning to be considered in experimental and modeling food web studies (van Leeuwen et al 2014), but there are few empirical examples of variation in species ontogeny in field settings across large geographic scales.…”

Ontogenetic diet changes and food partitioning of Haemulon spp. coral reef fishes, with a review of the genus diet

“…Third, species could differ in terms of where they use their resources, thereby exhibiting spatial niche partitioning (May and Hassell 1981;Chesson 2000). Food partitioning in regard to time and space seems to play an important role in reef fish coexistence (Armstrong and McGehee 1980;Pimentel and Joyeux 2010;Wollrab et al 2013) by reducing competition levels on sympatric species (Nithirojpakdee et al 2012). …”