A combination of environmental and landscape variables drives movement and habitat use in two Anaxyrus toads.

backgroundMovement patterns provide valuable information to guide habitat management strategies for declining amphibian populations. However, our understanding of movement ecology in amphibians is incomplete, as previous research has focused largely on environmental conditions driving movements rather than habitat drivers or landscape context. Here, we document the movement patterns of eastern American (Anaxyrus americanus americanus) and Fowler’s (Anaxyrus fowleri) toads as they transitioned from the breeding to the nonbreeding season. Specifically, we estimated the median distance migrated from breeding sites, identified the environmental and landscape level drivers of movement, estimated site fidelity to refugia on the basis of random walks, and evaluated refugia microhabitat use.

methodsWe tracked both taxa between late spring and summer in 2017, 2018, and 2023 in Virgina, USA. In total, we collected movement data from 46 eastern American and 57 Fowler’s toads on the basis of a combination of Harmonic Direction-Finding (HDF) and radiotelemetry relocation techniques.

resultsMedian distance moved from breeding grounds was similar for eastern American (63 m; interquartile range [IQR]: 43–122 m) and Fowler’s toads (64 m; IQR: 31–73 m), but the distribution of distances differed between the two taxa. Toads were more likely to move when minimum temperatures were high, after rain, in an area with a high proportion of conifers, and when far from water. Toads moved further when far away from trails. The probability and distance of a move differed among years. Both taxa exhibited site fidelity to daily refugia. Eastern American toads used woody structures and leaf litter as refugia more frequently than Fowler’s toad.

conclusionsThe distances which we tracked toads from their breeding grounds suggest that current regulations to protect amphibians are not biologically sound. To protect amphibians from decline, we suggest habitats should be protected at biologically meaningful scales based on data from tracking studies. Our results indicate that toads appear to use human trails as feeding substrates based on their activity and pattern of movement in relation to them. Trails likely improve foraging success by making invertebrate prey more obvious.