Habitat structural complexity mediates the foraging success of multiple predator species

Abstract

We investigated the role of freshwater macrophytes as refuge by testing the hypothesis that predators capture fewer prey in more dense and structurally complex habitats. We also tested the hypothesis that habitat structure not only affects the prey-capture success of a single predator in isolation, but also the effectiveness of two predators combined, particularly if it mediates interactions between the predators. We conducted a fully crossed four-factorial laboratory experiment using artificial plants to determine the separate quantitative (density) and qualitative (shape) components of macrophyte structure on the prey-capture success of a predatory damselfly, Ischnura heterosticta tasmanica, and the southern pygmy perch, Nannoperca australis. Contrary to our expectations, macrophyte density had no effect on the prey-capture success of either predator, but both predators were significantly less effective in the structurally complex Myriophyllum analogue than in the structurally simpler Triglochin and Eleocharis analogues. Furthermore, the greater structural complexity of Myriophyllum amplified the impact of the negative interaction between the predators on prey numbers; the habitat use by damselfly larvae in response to the presence of southern pygmy perch meant they captured less prey in Myriophyllum. These results demonstrate habitat structure can influence multiple predator effects, and support the mechanism of increased prey refuge in more structurally complex macrophytes.

The Impact of Mangrove Prop-Root Epibionts on Juvenile Reef Fishes: A Field Experiment Using Artificial Roots and Epifauna

“…Predators themselves may grow more slowly in very densely structured habitats (Spitzer et al 2000). The majority of studies on this topic, however, have examined habitat density, while only a few have discussed habitat shape or impacts of shape on trophic interactions (Beukers and Jones 1998;Warfe and Barmuta 2004).…”

Environment modulates population social structure: experimental evidence from replicated social networks of wild lizards

“…Habitat complexity has been defined in many ways, but generally refers to the complexity of physical or topographic structure in the environment (Kovalenko, Thomaz, & Warfe, 2012). Increased habitat complexity may benefit individuals if it, for instance, reduces predator effectiveness (Warfe & Barmuta, 2004), improves escape behaviour from predators (Jensen, Gray, & Hurst, 2003) or reduces male e male competition for females (Myhre, Forsgren, & Amundsen, 2013). Conversely it may be disadvantageous if it reduces the ability to detect predators or increases intraspecific competition and agonistic behaviour for food (Petren & Case, 1998).…”

Effect of surrounding trees and dry rush presence on spring zooplankton community in an urban pond complex

“…The Hanazato and Yasuno (1989) as well as Warfe and Barmuta (2004) suggest that in small water bodies a various combination of both vertebrate and/or invertebrate predators lead to a high diversity of zooplankton community structure. In the investigated ponds, invertebrate predators (Chaoborus and Odonata larvae) seem to have no strong negative impact on structuring either the rotifer or crustacean densities in the spring season.…”