In 1973, 20 alpine marmots, brought from the Austrian Alps, were introduced in the park and released in the Gemenele glacier lake caldera. Nowadays they are found all over the park, but the impact that this nonindigenous species had on other plants or animals is yet unknown. Also, after 1960, the brown trout was introduced in some of the park lakes. Studies are now being performed to check if they are responsible for the decline in amphibian population through these lakes, observed during the last years.