Multi-use buffer zones are intended to surround the core, and these should be managed for the economic benefit of local populations. Recently, the protected area approach has been extended to protect natural habitats in the international commons, including the High Seas, Antarctica and Outer Space. In these instances, parties have agreed to protect natural habitats not by establishing protected areas but by mutually agreeing to regulate or ban certain activities in the area concerned. This type of protection is illustrated by the Antarctica Treaty System where under the most recent protocol to the Antarctic Treaty the entire area is to be declared a protected area. The extent of the obligations created in these international instruments can vary from the mandatory to the purely hortatory.
Most examples are intermediate.
However, in order to become a party to the convention the State must nominate at least one area to be included in the list of significant wetland sites. The benefits of careful construction of the language of obligation are seen when attempts are made to enforce these undertakings. The nature of the obligation created by the World Heritage Convention has been the subject of judicial consideration in a series of cases in Australia, where the High Court held that the language of Articles 4 and 5 created a binding obligation on the contracting parties to do all they can to protect sites on the World Heritage List. It is clear that even though the effect of these obligations may be hard to quantify, they have been an important method of protecting the world's biological diversity.