Green and Golden Bell Frog - Ecology and Behaviour

Ecology and Behaviour

As a member of the tree frog family, the Green and Golden Bell Frog spends much time basking in the sun on vegetation, rocks and reeds, usually near water, or hopping around between such places. Unlike most frog species it is often active during the day. When handled, this species secretes a slimy acrid mucus which consists of 17 aurein peptides. Thirteen of these show broad-spectrum antibiotic and anti-cancer activity, which is useful in fighting off harmful microorganisms. The secretion makes the frog slippery and hard to grip, and is poisonous to some other species of frogs, so it is a useful defensive tool for Green and Golden Bell Frogs. Male Green and Golden Bell Frogs often fight one another if they come within 1 m of each other, frequently leading to injuries.

The Green and Golden Bell Frog has been detected in a wide range of habitats. It is generally associated with coastal swamps, wetlands, marshes, dams, ditches, small rivers, woodland, and forest; but populations have also been found at former industrial sites (for instance, the Brickpit). It has even been found in human vessels such as bathtubs. The requirements of its habitat have been difficult to determine, for it has been found in a wide range of water bodies except fast-flowing streams. It is most typically found in short-lived freshwater ponds that are still, shallow, unshaded and unpolluted; and it tends to avoid waters that contain predatory fish, whether native or introduced. However, it is most often found in areas that have been affected by human habitation. The frog prefers water bodies that support emergent vegetation such as reeds and bullrushes for basking, and winter habitats consist of available shelters around the breeding site, which can be vegetation, rocks, rubbish or human debris and discarded building materials. Grassy habitats are usually close at hand to provide suitable terrestrial feeding grounds. It prefers waterways with a substrate of sand, rock or clay, and can tolerate a wide range of water turbidities, pH, oxygen and temperature, although these can hamper physical growth. Although its legs provide much grip, the frog does not choose to climb trees or live up them to any significant extent. They spend most of their time within 10 cm of the ground and rarely venture more than a metre above the ground. The Green and Golden Bell Frog also has the ability to sit still for several minutes.

The Green and Golden Bell Frog can travel far in a single day or night; distances of 1–1.5 km have been recorded. Tagging experiments have shown that some can move up to 3 km and in total and that some travel several kilometres from the closest breeding habitat. However, there is evidence that the species tends to return to or remain at an identified site, provided that the habitat stays appropriate for its needs, else it will move away. The Green and Golden Bell Frog also favours areas with the greatest habitat complexity, and as such, this is a core component of habitat-based strategies to protect the species. In general, the frogs stay within areas of 100–700 m2 The frog is well-equipped for survival on land. They can rehydrate by absorbing moisture through their ventral skin, and evaporative water loss occurs at a very low rate indicative of a watertight skin. Some have been observed up to 400 m from the nearest body of water.

During the winter months, the frog tends to be inactive, staying in one place, whereas it moves around during the warmer months to search for food and mating partners. During winter, the frog does become active for brief periods during warm or wet weather. It has been claimed by some scientists that in cold conditions, the frogs hibernate, based on observations of some being uncovered in a "torpid" state, but this has yet to be proven with rigorous physiological studies. Although the frog is active during the day, this is restricted to leaving its shelter to sunbathe. It tends to not actively feed or forage during the day, hunting insects only if they move into their vicinity.

The Green and Golden Bell Frog's reproduction depends on salinity and water temperature. Salinity affects tadpoles' development and metamorphosis, and breeding is significantly slowed for ponds that measure 20 °C (68 °F) or below. The Green and Golden Bell Frog tadpoles can tolerate salinity levels of six parts per thousand (ppt) without any apparent effects, while salinity of 8 ppt or higher decreases growth rates and increases mortality rates. On the other hand, salinity levels of at least 1–2 ppt can be beneficial to the Green and Golden Bell Frog because this kills pathogens such as the chytrid fungus. The pH of the pond is not found to affect the likelihood of the eggs to hatch for values of the pH between 4 and 10.