Book Reviews

The authors start their book by referring to the classic works of Senander (1901), Ridley (1930), Milller-Schneider (1977), Van der Pijl (1982) and Luftensteiner (1982), and ask themselves what more could be said about plant dispersal. In my opinion the work of Susanne Bonn and Peter Poschlod can be added to the list of classics. The authors are not happy with the fact that most publications on dispersal only take into account the morphology of dispersal units such as plumes, hooks and awns, but do not include the processes of dispersal. Moreover, until now dispersal has been discussed as a potential without taking into account the need to find a safe site, and thence the possibilities of establishment. In the opinion of the authors, the issue of dispersal has been discussed too hypothetically until now; more experimental tests are needed. Two examples of what the authors mean by their criticism are: (i) calcareous grassland species found at ant hills are believed to be dispersed by ants – however, many of these species have no elaiosome, and such species have been recorded to be transported by ants; (ii) dispersal by water has been recorded for diaspores with a whole range of different morphological characteristics. Theories and models are often derived from anemochory and ornithochory, but hardly ever from anthropogeneous dispersal, despite the fact that the landscape is completely dominated by human impact. Zoochory is supposed to have played an important role in the pristine post-glacial landscape. Again not dispersal per se, but it must have been important in combination with disturbances by the animals, thus creating gaps for the establishment of dispersed diaspores. In fact, these wild animals were supposed to be the predecessors of man, who played an overwhelming role by increasing agricultural activities in the dispersal of herbs and grasses in particular.