Role of habitat complexity in predator–prey dynamics between an introduced fish and larval Long-toed Salamanders (Ambystoma macrodactylum)

Abstract

Predation by nonnative fishes has reduced abundance and increased extinction risk for amphibian populations worldwide. Although rare, fish and palatable amphibians have been observed to coexist where aquatic vegetation and structural complexity provide suitable refugia. We examined whether larval Long-toed Salamanders (Ambystoma macrodactylum Baird, 1850) increased use of vegetation cover in lakes with trout and whether adding vegetation structure could reduce predation risk and nonconsumptive effects (NCEs), such as reductions in body size and delayed metamorphosis. We compared use of vegetation cover by larval salamanders in lakes with and without trout and conducted a field experiment to investigate the influence of added vegetation structure on salamander body morphology and life history. The probability of catching salamanders in traps in lakes with trout was positively correlated with the proportion of submerged vegetation and surface cover. Growth rates of salamanders in enclosures with trout cues decreased as much as 85% and the probability of metamorphosis decreased by 56%. We did not find evidence that adding vegetation reduced NCEs in experimental enclosures, but salamanders in lakes with trout used more highly vegetated areas, which suggests that adding vegetation structure at the scale of the whole lake may facilitate coexistence between salamanders and introduced trout.

Recovery of high mountain Alpine lakes after the eradication of introduced brook trout Salvelinus fontinalis using non-chemical methods

“…In lakes DRE and DJO, where a residual population was still present, the recovery process was rapid (as documented by egg-masses trends). In these lakes, population persistence was probably facilitated by the presence of aquatic vegetation, providing an antipredatory refuge (Kenison et al 2016). However, fish introduction often causes the local extinction of amphibians (Bradford et al 1993;Orizaola and Braña 2006;Miró et al 2018) and population recovery is aided by the presence of immigrant individuals (Vredenburg 2004).…”

Disentangling effects of invasive species and habitat while accounting for observer error in a long‐term amphibian study

“…, Anderson and Semlitsch , Kenison et al. ). Dominant plant species, such as invasive reed canarygrass ( Phalaris arundinacea ), can affect both native and invasive amphibians by modifying wetland structure and function, prey resources, and water chemistry (Spyreas et al.…”

“…Moreover, native-invasive interactions can be intensified or mediated by local and landscape habitat characteristics including climate (Melbourne et al 2007. Within-pond physical heterogeneity and vegetation structure can increase availability of refugia from predators and diffuse competition (Hartman et al 2014, Anderson and Semlitsch 2016, Kenison et al 2016. Dominant plant species, such as invasive reed canarygrass (Phalaris arundinacea), can affect both native and invasive amphibians by modifying wetland structure and function, prey resources, and water chemistry (Spyreas et al 2010).…”

Genetic diversity and structure of two endangered mole salamander species of the Trans-Mexican Volcanic Belt

“…We recommend divisions to be built higher and periodically revised to avoid holes from which trout can escape. Trout farms are affecting the populations of mole salamanders; several studies have demonstrated that the predation by introduced fish has been linked to reductions in the population's size, survival, growth, egg predation, reproduction and organic waste pollution of the rivers (Valiente 2006;Mercado-Silva et al 2008;Drake et al 2014;Kenison et al 2016) since mole salamanders do not recognize trout as predators and their survival decreases proportionately (Petranka et al 1987;Petren et al 1993;Relyea 2001;Pilliod et al 2013). Trout farms have been encouraged by Mexican governmental agencies and recommended as a potential conservation tool for native forests (López-García et al 2014;Zamora et al 2018), so the best strategies may include isolating trout farms from streams containing native amphibians, increasing efforts to prevent trout escaping and attempting to eradicate populations of escaped trout from streams, thereby balancing the economic and conservation value of trout farms with their potential negative effects on native amphibians (Zamora et al 2018).…”