Terrestrial habitat and ecology of Fowler's toads ( Anaxyrus fowleri)

Habitat loss is the primary driver of global amphibian declines and thus preserving habitat is our best hope for preserving species at risk. The habitat needs of amphibians are complex due to terrestrial and aquatic requirements throughout their life history. Many pond breeding amphibians spend the majority of their life cycle within terrestrial environments and thus terrestrial habitats are critical to their persistence. Cryptic and fossorial behavior makes observations of amphibians in terrestrial habitats difficult. Our knowledge of the terrestrial ecology of amphibians is therefore incredibly limited. I review the literature on habitat loss, amphibian declines and terrestrial habitat use by amphibians with specific attention to refuge seeking behavior (CHAPTER ONE). I used radio-tracking to investigate the behavior of Fowler's toads (Bufo fowleri) in the beach dune ecosystem of Long Point, Ontario. Refuge seeking behavior by these animals is associated with specific components of the dunes and is predictable based on elevation, slope and distance from the lakeshore. Refuge sites placement is not random, but instead represent a trade-off between risk and reward (CHAPTER TWO) . Philopatry in Fowler's Toads is driven by fidelity to refugia. These locations are used repeatedly on consecutive days, and even when they are not new sites within 10 meters of the previous day's refuge are most often chosen. Occasionally, however toads relocate their refuge sites as much as 700 m overnight (CHAPTER THREE). This contributes to the wide variation in the home range sizes of Fowler's Toads, as does method of calculation and search effort, while there is little apparent influence of intrinsic biological factors. The effect of search effort on range size is reduced in robust location data sets with more than thirty locations for each animal. A minimum home range estimate of 3517m2 is suggested under the caveat that range sizes may have no hard upper limit (CHAPTER FOUR).