English: Open data provided by the EU Space Programme, and in particular by its Copernicus Earth Observation component are key assets in the design, monitoring and assessment of the impact of protection and conservation measures for various ecosystems. They are used to design, monitor and assess the impact of key environmental policies of the European Union and support governmental authorities, researchers, non-governmental organisations and citizen scientists alike. This image, acquired by one of the Copernicus Sentinel-2 satellites on 1 March 2021, shows the Brijuni National Park in Croatia, an archipelago of fourteen small islands off the western coast of Istria, in Croatia. Among the other island groups scattered along this part of the Adriatic Sea, the Brijuni archipelago stands out due to its extraordinary biological diversity and the remnants of Ancient Roman architectural cultural heritage it hosts. About 80% of the area of the national park that has also been protected under the Natura 2000 Directive is marine, owing to its crucial role as a hatching ground. The area surrounding the Brijuni Islands is an oasis for the marine fauna typical of the northern Adriatic Sea, such as sea turtles and dolphins, and the seabed hosts a rich ecosystem of sponges, shellfish, sea urchins, crustaceans and fish. This precious natural and cultural heritage can be better preserved thanks to the Copernicus Sentinel satellites and Copernicus services. They provide open data to assess important ecological parameters such as vegetation health, risk of drought, air and water quality, as well as services such as oil spill detection, land cover and land use monitoring, and wildfire early warning and monitoring.