To a very great extent, cliffs are places that are of interest to everyone and no-one at the same time. This paradox attracts us and we think it will attract others when it becomes better known. People on all continents see images of cliffs in a wide variety of mass media and are consequently drawn as though pulled by a magnet to cliffs or habitats with extreme topography. Cliffs are sites with enormous spiritual value and may even be habitats that have given rise to a wide variety of our food plants, garden weeds and commensal animals. Yet these same sites have zero area when photographed from space, have attracted little scrutiny from scientists, and have received almost no legal protection from various forms of commercial exploitation. Some may be inclined to protest the last two statements based on the content of the book so far, but when one compares the vast and easily accessed literature for other habitat types, our conclusions are justified.

The literature that we have reviewed and discussed in the preceding chapters almost always focuses on particular organisms, groups of organisms or specific aspects of cliff ecosystems without considering them as ‘places’ in the same way as lakes are considered as distinctive habitats by limnologists or forests by forest ecologists. A result of the particular organization that we have selected is that we may have reinforced rather than eliminated the idea of separate structures and functions on cliffs.