5.2 Geological drivers
Earth is constantly being modified under the influence of its deep-lying geology. These geological drivers often manifest themselves in the forms of moving continental plates, earthquakes, volcanoes or soil-erosion processes. These which in turn often occur as geological events, such as glacial cycles and mountain-building episodes, with impacts that can be seen at the local scale up to regional and global scales. Such modifications in the landscape allow the potential for new species to arise and succeed in the newly modified environment.
At this juncture, it is worth noting that, as instability creates opportunities for biodiversity to arise or make space for others, so a long period of comparative stability could provide an environment in which evolution can operate at will. This may result in a high diversity of endemic species (i.e. species not found anywhere else other than where they originated). A well-known example of this principle is South Africa’s Cape Floristic Region, a biodiversity hotspot where over 9000 species of plants, over 70% of which are endemic, live in area of just 90,000 square kilometres – roughly the size of Ireland. In contrast, Ireland has just a quarter of this number, checking in at 2300 species.