On the shoulders of some ecologists and conservation biologists rests the responsibility for guarding environmental systems from excessive abuse by humans. To this end, policy makers may be advised to introduce restrictions on behaviour of individuals and firms alike. Needless to say, such proposals often receive a hostile welcome, especially amongst private industries, where it is sometimes felt that ecologists overstate the importance of their case, proposing too stringent regulation too early and thereby causing excessive costs. Early signalling of resource depletion may be a rational (and indeed necessary) response by ecologists to the vagaries of policy making.