The islands are small habitats, differentiated and isolated to some extent from the rest of the world, which makes these pieces of land fascinating places from the point of view of ecology and the evolution of their flora and fauna.
And it is that each island presents a unique biological history , which provides important information to researchers about how the different ecological and evolutionary forces operate throughout the world .
Isolation and endemic species
How can we know that the current rate of extinction of animal species on a planetary scale is above normal? Studying an island and measuring, for example, the relationship between land area and natural biodiversity .
In other words, knowing the population density of flora and fauna, we can learn more about how species on the continents become extinct or flourish. One of the reasons why this density is higher on islands is because there is a greater scarcity of predators and competitors.
Nonetheless, the low species richness on islands makes them extremely vulnerable to invasion by introduced species .
The islands are also home to most of the planet’s endemic species (that is, species found nowhere else), and some have been separated from the rest for so long that they have formed distinct families, like the kiwis of New Zeeland. Others have become extinct on the continents, but survive on islands, like the lemurs of Madagascar.
Therefore, the islands are almost like alien planets that must be carefully preserved and studied, as Michael J. Benton explains in his book The Seventy Great Mysteries of the Natural World :
The ecology and evolution of island biodiversity remain a major focus of research. Reconstructions of evolutionary trees using molecular evidence reveal the history of colonization and diversification of the islands. Comparisons with their close continental relatives show us the changes they have undergone, and studies of recent colonization identify the pressures and constraints of natural selection on these species.