Environmental movements are networks of informal interactions that may include, as well as individuals and groups who have no organizational affiliation, organizations of varying degrees of formality (including even political parties, especially Green parties) that are engaged in collective action motivated by shared identity or concern about environmental issues. Such networks are generally loose and uninstitutionalized, but their forms of action and their degree of integration vary. Environmental movements are, however, identical neither with organizations nor with episodes of protest. It is only when organizations (and other, usually less formally organized actors) are networked and engaged in collective action, whether or not it involves protest, that an environmental movement exists (see Diani 1995: 5; Rootes 2004).