|Site types that use this protocol||
The common frog (Rana temporaria) has been selected for inclusion in the ECN programme as an example of a ubiquitous predatory amphibian. Adult frogs feed mainly on insects, slugs and snails but also eat woodlice and the larvae of moths and butterflies. During the breeding season, frogs live in shallow ponds and ditches, but spend much time on land during the rest of the year. The frog population is therefore affected by conditions on land as well as in the shallow water bodies in which they breed, including agricultural drainage, modification of breeding sites, acidification of fresh waters and pollution by fertilizers and from other sources. It is difficult to monitor populations of adult frogs, but a rough approximation of frog colony size in a pond can be obtained by monitoring spawn masses. Since frogs usually spawn in shallow water they are therefore usually reasonably accessible for monitoring purposes.
Spawn development and the pond environment are monitored.