The site consists of the Otra river and surrounding areas. The river is the largest in the southernmost part of Norway, and has been regulated for hydroelectric purposes to a great extent, although no dams exist within the site itself. Forests cover most of the surrounding area, mainly consisting of pine Pinus.
After several decades of very low breeding numbers in Norway, due to the severe influence of acid rain on freshwater ecosystems, Pandion haliaetus are now increasing in this area, probably as a result of full national protection of the species in 1962, and re-colonization following the re-introduction of trout Salmo trutta and the liming of rivers and streams.
Pressure/threats to key biodiversity
Commercial fishing of trout Salmo trutta and perch Perca fluviatilis utilizes the same fish populations as Pandion haliaetus, and should be managed so as to secure the birds' food-supply. Numbers of Pandion haliaetus are monitored by local birdwatchers (NOF Aust-Agder), and data on the number of pairs and nesting success exist from about 1980. One nest-site has been protected by the local authorities after it was exposed to disturbance by commercial tourism. Protection includes restrictions on forestry and on public access in the area during the breeding season.