A search of the Internet finds many sites and publications, targeted at both scientists and the general public, that deal with the 'pollination crisis', but none that even mention a 'dispersal crisis'. Part of this difference reflects the importance of pollination for agricultural crops, while no major crop depends on natural seed dispersal, but many authors also suggest that there is - or soon could be - a pollination crisis in natural ecosystems and that there is therefore a need for the active conservation of pollination interactions (e.g. Buchmann and NabSEhan, 1996; Allen-Wardell et al., 1998; Kearns et al., 1998; Steffan-Dewenter et al., 2005). The major reasons for this concern about pollination systems are the dependence of most species of plant on pollination by animals, especially insects, and the evidence that some pollinator populations (most clearly, of exotic honeybees; Ghazoul, 2005a) have experienced dramatic declines in recent decades. A priori, plants that depend on the services of animals are expected to be more vulnerable than those that do not, because the vulnerabilities of the mutualist are added to those of the plant itself.
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