Bush and a group of scientists from England have continued the work started by the Dutch team and have since tagged every tree on large sections of the island, allowing them to note the growth or death of an individual plant. With these data, Bush can tell which types of plant species are prone to extinction and which are capable of growing to dominate the forest canopy. His results show striking new patterns, contrary to accepted theory. The larger the island, the greater the number of species. Where immigration and extinction rates meet, an equilibrium is established and the species number remains stable.
Mature forests are ones in which the equilibrium has been reached.
The plant species he has observed respond very specifically to their habitat requirements. The number of species present on an island is then dependent on what the island's habitat is like, rather than simply its size. The plant species are also not going extinct as predicted by the models. The immigration of new species is following a decreasing pattern, but the expected exponential increase in extinction of species has simply not occurred. Extinction rates have stabilized, remaining relatively rare events.