Shifts in amphibian population dynamics in response to a change in the predator community

Benedikt R Schmidt,Raluca I Băncilă,Michael Schaub,Tibor Hartel,Kurt Grossenbacher

doi:10.1002/ecs2.3528

Benedikt R Schmidt, Raluca I Băncilă + Show 3 more

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https://doi.org/10.1002/ecs2.3528

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Abstract

AbstractPredation can affect prey behavior, demography, abundance, and distribution, particularly in lentic freshwater ecosystems. Fish are predators known to reduce the abundance of their prey and to restrict the distribution of species. Using time series which spanned 43 and 22 yr, respectively, we analyzed the effect of a change in the fish predator community on the dynamics of two pond‐breeding amphibian populations (Rana temporaria and Rana dalmatina). Specifically, we used a state‐space time series model which allows for density dependence and observation error, to ask whether the change in predation risk affects population growth rate and the return point around which the populations fluctuate. The results showed that the type of observation error assumed did not affect the biological parameters. We found evidence for density dependence in both populations. The effect of the change in fish predation on population growth rate and the return point was strong in the population where fish invaded a previously fish‐free pond. The effect was weaker in the population where the change was from cyprinid fish to pike. The results showed that fish predation can have strong effects on amphibian population dynamics. The observed population dynamical pattern is phenomenologically similar to alternative stable states.

Highlights

Predation is a biotic interaction that is well known to affect prey populations
Using time series which spanned 43 and 22 yr, respectively, we analyzed the effect of a change in the fish predator community on the dynamics of two pond-breeding amphibian populations (Rana temporaria and Rana dalmatina)
The results showed that fish predation can have strong effects on amphibian population dynamics

Summary

Introduction

Predation is a biotic interaction that is well known to affect prey populations. Predators can have both direct and indirect effects on prey populations. They may reduce the performance of prey species and alter competition within prey communities (Morin 1981, Peacor and Werner 2001, Anholt et al 2005). Predation by fish is one of the main forces that structures freshwater aquatic communities (Wellborn et al 1996) and that restricts and drives species distributions across the freshwater habitat gradient (Bradford et al 1993, Eaton et al 2005, Werner et al 2007); predation by fish can even affect adjacent terrestrial communities (Epanchin et al 2010, Rudman et al 2016). The introduction of fish into previously fish-free habitats can have devastating effects on prey communities (Knapp et al 2001, Nystrom et al 2001, Kats and Ferrer 2003)

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