Historical background The BBC Radio Science Unit has its roots in two radio networks, going back more than 40 years. In the late 1950s, BBC External Services (now World Service), appointed a science correspondent and began a weekly science magazine programme. Initially called `Science and Industry', it changed its name in about 1964 to `Science in Action'. It is still running today, after more than 2000 editions, probably making it the longest running science show on radio.

The international symposium Science on air: the role of radio in science communication was held in Trieste on 1 and 2 October, 2004. To our knowledge, it is the first conference ever specifically held on science in radio, and it is certainly the first time science radio journalists, researchers, and media experts from 16 different countries met to discuss their journalistic practice and the role of radio in science communication. The main results are presented in this section.

I would like to start with a brief news item in the August 1999 issue of National Geographic which gives some food for thought: "With 5,000 climbing routes, such as Double Dogleg and Walk on the Wild Side, California's Joshua Tree National Park attracts about 140,000 enthusiasts a year to test their skill on granite boulders. But some visitors view their metal bolts as defacements hammered into rocks.

The concept of a biosphere reserve was adopted by UNESCO, within the MAB Programme, launched in 1971, in order to promote and to demonstrate the harmonious relationships that should exist between people and the environment and, particularly, to promote a harmonization model of the environmental protection needs with those of the sustainable economical-social development. All the international conventions, the management and action plans accomplished in order to achieve the sustainable development objectives underline the great importance to establish a constructive dialogue, with impact on the long term decisions, between the decision makers and the wide public (especially with the local population).

The Regional Park of the Po River Delta1 was set up in 1988 (it belongs to a Consortium of Public Bodies). It extends over 54,000 hectares of land and stretches across 45 km of the Italian Eastern coastline (45 km of the more than 90 km that go between the provinces of Ferrara and Ravenna)2 and is one of the largest and most significant natural parks in Italy.

Natural parks are a place where science communicates with the public, involving dimensions ranging from the knowledge of living species to the relationship between man and nature, the environmental policy decisions and the anthropic impact assessments. Natural parks are therefore an important arena for scientific communication where the "shared participation" tools play a fundamental role. To this end, we report a few international experiences that illustrate the role of the interest holders and the importance of coordination of the parties involved in the management of parks.