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.
Loire
Most amphibians of the Loire are found in the slow flow areas near the delta, especially in the floodplain, marshes and oxbows. They are dominated by the fire salamander ("Salamandra salamandra"), frogs and toads. The toads include "Bufo bufo", "Alytes obstetricans", "Bombina variegata", "Bufo calamita", "Pelobates fuscus" and "Pelobates cultripes". The frogs are represented by the Parsley frog ("Pelodites punctatus"), European tree frog ("Hyla arborea"), Common Frog ("Rana temporaria"), Agile Frog ("R. dalmatina"), Edible Frog ("R. esculenta"), Perez's Frog ("R. perezi"), marsh frog ("R. ridubunda") and Pool Frog ("R. lessonae"). Newts of the Loire include the Marbled Newt ("Triturus marmoratus"), Smooth Newt ("T. vulgaris"), Alpine Newt ("T. alpestris") and Palmate Newt ("T. helveticus").