Seasonal changes in the migratory behaviour of the toad Bufo bufo: direction and magnitude of movements

Abstract

The migratory behaviour of the toad Bufo bufo was studied from February 1985 to April 1986 in the submontane region of Bavaria, West Germany. Toads were fitted with a mechanical tracking device to record individual paths of migration. Three aspects of migratory behaviour were quantified: orientation in relation to the breeding site, straightness of path, and locomotory activity. The annual activity period began with migration from the hibernation sites to the breeding pond in April. The paths went straight towards the breeding pond independent of the distance (70-420 m). During the period of oviposition the preference for the breeding site direction vanished and toads moved away from the breeding pond, but in less straight paths than before. In summer migratory activity decreased considerably and was restricted to small areas, the home ranges, at distances of 55-1600 m from the natal breeding pond. The straightness of path was rather low, because toads often returned to their starting points. During rainy nights toads occasionally left their home ranges for extensive excursions. In autumn most toads again migrated towards the breeding pond, but paths were significantly less straight and direct than in spring. However, toads stopped before reaching the breeding pond and hibernated in holes or under the leaf layer. The mortality rate of tracked toads was about 45%. The relative influence of 17 environmental variables on locomotory activity was evaluated by principal component analysis and stepwise multiple regression. Temperature at night and rainfall variables accounted for significant amounts of variance, whereas temperature by day, air humidity, and atmospheric pressure showed no correlation. Activity decreased if temperature approached 0° C or after long periods without rainfall. Within a certain range of tolerance, however, the locomotory activity of the toads was widely independent of environmental factors, indicating that endogeneous factors are more important sources of variation in the migratory behaviour of these toads than commonly assumed.

Metacommunity dynamics of amphibians in years with differing rainfall

“…In turn, high amounts of precipitation permit spatial expansion which is reflected by an increase in occupancy (Cayuela et al 2012). Lower migration activity in relation to a low amount of precipitation in the breeding season was observed in several species (Sinsch 1988;Hartel 2008). Jakob et al (2003) found in a Mediterranean pond system that some species skipped the breeding season when unfavourable hydrological conditions occurred.…”

“…Gibbs 1998; Vos and Chardon 1998; Lehtinen et al 1999;Ficetola and De Bernardi 2004;Weyrauch and Grubb 2004;Curado et al 2011). While today the habitat preferences of most European amphibian species are relatively well known (Bell 1977;Sinsch 1988), our knowledge on the drivers of the assembly and dynamics of their communities is much more limited, especially at the landscape scale.…”

Postbreeding Movement and Habitat Use of the Plateau Brown Frog, Rana kukunoris, in a High-Elevation Wetland

“…Site fidelity may give males a competitive advantage when females arrive to breed in the spring. Different energetic requirements associated with reproduction may require females to travel farther for foraging, and larger body sizes may allow females to do so (Turner, 1958;Sinsch, 1992;Bartelt et al, 2004). The reason movement patterns do not differ between sexes of R. kukunoris is unknown, but the lack of difference may be related to the lack of sexual size dimorphism in this species (Fei et al, 2009).…”

“…For example, with explicit knowledge of the composition and arrangement of preferred overwintering, breeding, and summer habitats of Wood Frogs (Lithobates sylvaticus), it was apparent that much less habitat area would require protection than perceived through traditional core habitat models (Baldwin et al, 2006). Sinsch (1990) suggested that habitats must provide four major resources for the annual activities of anurans: reproduction, nutrition acquisition, hibernation, and aestivation. In some circumstances, these resources may be located in the same habitat patch, and anurans need not consume energy resources to migrate (Pilliod et al, 2002).…”

“…In some circumstances, these resources may be located in the same habitat patch, and anurans need not consume energy resources to migrate (Pilliod et al, 2002). For many temperate anurans, however, some or all of those resources are spatially separated, thereby requiring seasonal migrations among different habitat patches (Sinsch, 1988;Pilliod et al, 2002;Muths, 2003), in particular for the use of resources that are critical to the survival of an animal and can only be found in specific habitat patches, such as overwintering sites at high altitudes or latitudes (Dunning et al, 1992;Matthews and Pope, 1999;Pilliod et al, 2002). Microhabitats such as vegetation or mammal burrows with proper temperature and relative humidity are important in harsh environments to allow amphibians to maintain suitable body temperatures and prevent predation during their terrestrial movements (Spieler and Linsenmair, 1998;Trenham, 2001;Johnson et al, 2008).…”