This blog was written by Dr. Laurence Jarvis, Head of Conservation at Froglife. To find out more about Froglife, please visit their website.
Trees are a vital habitat for a range of amphibians, particularly the common toad (Bufo bufo) which may spend up to 90% of its life on land. Common toads spend the winter in terrestrial habitats such as scrub, dense vegetation and woodland. To avoid frosty conditions common toads will often go underground into the soil, or make their way inside small mammal burrows such as those of the wood mouse or bank vole (Figure 1). They will also bury themselves deep within leaf litter. In warmer conditions common toads may come to the surface and hide under logs. In early spring adults will emerge from their winter torpor and migrate towards established breeding ponds. Here they will breed, with the females laying strands of spawn. Unlike many other amphibians within the UK, common toads will only spend a few days at breeding ponds before departing for land. Adults and juveniles will spend the remainder of the year foraging for small invertebrates such as beetles, woodlice, worms and ants. Common toads will move considerable distances away from breeding ponds and maximum distances have been recorded between 500 m and 5,000 m. During this period of movement, common toads will utilise a range of habitats.
Woodland areas are of vital importance to common toads in providing habitats where they can rest, forage and grow. Research has shown that this species orients towards areas of woodland when leaving breeding ponds and that the presence of woodland enhances breeding success. Through the late spring and summer when temperatures are high and moisture levels low, the woodland floor is an ideal place for common toads. Like all amphibians, common toads are vulnerable to desiccation in dry conditions. Decaying logs and damp leaf litter provide suitable microhabitats to avoid desiccation and allow opportunities for foraging (Figure 2). Placing piles of dead wood on the ground within woodland areas will allow individuals to crawl underneath and hide in the damp, cool conditions beneath. Common toads will also dig into loose soil when weather conditions are too hot and dry.
Wildlife corridors are important in maintaining connectivity between habitats. Strips of woodland, scrub and hedgerow provide vital routes for toads to enable them to migrate between winter hibernation sites and spring breeding ponds. The cover provided within such corridors of vegetation allows opportunities for toads to forage and rest with protection from predators such as crows and foxes. Habitat fragmentation is becoming an increasing problem in precipitating declines in the common toad and provision of small corridors of habitat connecting breeding ponds with woodland areas is vital in ensuring population survival.
The decline of the common toad
Common toads are estimated to be in decline across the UK which is worst within the southeast of England. Recent research published by Froglife and the University of Zurich have shown a decline in common toad populations of 68% in the UK over the past 30 years. This is due to a combination of climate change, habitat loss and fragmentation, intensification of agriculture and introduced diseases. Providing suitable terrestrial habitats for common toads in the form of woodland, scrub and dense vegetation will be vital in ensuring continued survival of this species over the coming decades within the UK.
Both photos are by Froglife. The cover photo shows a common toad (Bufo bufo) emerging from soil burrow.