The Gesäuse Nationalpark and the Johnsbach valley belong to the Ennstal Alps, a part of the Northern Limestone Alps. They are situated in the province of Styria in the center of Austria. Together, they form the joint test site named Gesäuse-Johnsbachtal. This region is characterized by a mountainous landscape which is cut by the river “Enns”. In the north, it borders Eisenwurzen Nature Park and is only 6 km away from the Kalkalpen, a National Park in Upper Austria. In the south, the borders are the Eisenerzer Alps. The total area of the site is about 155 km². The terrain shows a great elevation range from 600-700 m in the Johnsbach valley to over 2300 m in the summit region of the Gesäuse, with Hochtor (2369 m) being the highest mountain. Due to the great range of altitude differences within small areas the Gesäuse-Johnsbachtal shows extremely diverse habitats and, consequently, species of animals and plants. In general, the landscape is dominated by mountain forests along with high Alpine rock formations and meadows. These complex topographic, hydrological, geological, geomorphological and meteorological conditions pose a scientific challenge for all kinds of environmental monitoring and modeling.