Newt
Newts, as with salamanders in general and other amphibians, serve as bioindicators because of their thin, sensitive skin and evidence of their presence (or absence) can serve as an indicator of the health of the environment. Most species are highly sensitive to subtle changes in the pH level of the streams and lakes where they live. Because their skin is permeable to water, they absorb oxygen and other substances they need through their skin. Scientists study the stability of the amphibian population when studying the water quality of a particular body of water.
Triturus
Like other newts, "Triturus" species are carnivorous and feed mainly on invertebrates. During the land phase, prey include earthworms and other annelids, different insects, woodlice, and snails and slugs. During the breeding season, they prey on various aquatic invertebrates, and also tadpoles of other amphibians such as the common frog or common toad, and smaller newts. Larvae, depending on their size, eat small invertebrates and tadpoles, and also smaller larvae of their own species.