The effects of brown trout (Salmo trutta morpha fario) on habitat selection by larval Fire Salamanders (Salamandra salamandra): a predator-avoidance strategy

Abstract

Predatory fish can have a major impact on aquatic amphibian assemblages. Knowledge regarding the influence of habitat heterogeneity on predator–prey dynamics is extensive, but not much is published on how the habitat structure influences the co-occurrence of brown trout (Salmo trutta Linnaeus, 1758 morpha fario) and Fire Salamander (Salamandra salamandra (Linnaeus, 1758)). I examined the microhabitat distribution of larval salamanders relative to the presence of brown trout and stream morphology, hypothesizing that larval salamanders will increase their habitat use in the presence of trout to avoid predation. Fish and salamanders were sampled with an electroshocker in 62 instream habitat patches. In the stream zone populated by brown trout, larval salamanders avoided high-quality habitats such as pools, whereas they strongly preferred them in the fishless zone (their densities were ∼10 times lower in pools than in riffles). Brown trout mainly occupied deeper pools. The co-occurrence of larval Fire Salamanders with trout suggests the presence of an effective predator-avoidance strategy. The predator-avoidance response and habitat-use pattern decreased interspecific overlap, leading to the use of different instream spaces. Heterogeneous habitats enable habitat partitioning between larval salamanders and brown trout, which means that the natural characteristics of streams promote coexistence between fish and amphibians.

Paleoenvironments of Late Devonian tetrapods in China

“…4b) and Hyneria 12 found in the same deposits. In modern streams and lakes, salamanders take refuge from predation by fish in woody debris 57,58 . The importance of woody debris for modern amphibians is now increasingly appreciated from studies of human deforestation 57,58 .…”

Species‐specific foraging behavior and diets of stream salmonids: An implication for negative impacts on native charr by nonnative trout in Japanese mountain streams

“…Brown trout and brook trout habitat and foraging niches have also been studied in detail in the native and invasive ranges (Horka et al, 2017), although detailed studied are still lacking in Japan. Brown trout inhabit a wide range of habitats and have been found foraging on aquatic and terrestrial invertebrates in streams (Becer‐Ozvarol et al, 2011; Cochran‐Biederman & Vondracek, 2017), while large individuals often prey on fish (Jensen et al, 2008), amphibians (Bylak, 2018), and in some cases even small birds and mammals (Milardi, Kakela, et al, 2016; Milardi, Thomas, & Kahilainen, 2016). Brook trout inhabiting stream habitat also typically forage on aquatic and terrestrial invertebrates (Hubert & Rhodes, 1989; Tiberti et al, 2016) and have been shown to have overlapping foraging niches with brown trout when found in sympatry (Horka et al, 2017).…”

Impacts of river fragmentation on limiting individual dietary specialization of Amazonian predatory fish

“…Like other populations of predators, predatory fish, normally considered generalists, can have populations composed of both generalist and specialist individuals, that is, individuals of the same species can use resources in different ways ( Bylak, 2018 ; Balme et al, 2020 ). Some studies have suggested that among-individual niche variation or individual dietary specialization is a common phenomenon that can affect the ecological dynamics of a population, contribute to niche variation within the population ( Bolnick et al, 2003 ), and even alter community ecology more broadly.…”

“…In response to interspecific competition, individual specialization may increase or decrease depending on the distribution of resources. If the competitor reduces the abundance of preferred resources, individuals may use alternative resources or change habitats depending on resource availability ( Futuyma & Moreno, 1988 ; Bylak, 2018 ). In the tropics, ecological opportunity (high diversity of resources) may be more important than interspecific competition in promoting niche variation among individuals ( Araújo & Costa-Pereira, 2013 ).…”