Why Care About Species That Have Gone Extinct?

Increasing rates of habitat destruction and exhaustive exploitation of natural resources have necessitated the rapid collection of accurate data on the existing state of global biodiversity. The 1992 U.N. Conference on Environment and Development (known as the Rio Earth Summit) produced eight internationally endorsed documents (including the Convention on Biological Diversity) that stress the importance of developing programs for the proper measurement of recent changes in species diversity.

Extinctions are irreversible changes in global biodiversity - therefore, we are very concerned about measuring them accurately. Surveys describing the numbers and patterns of recent extinctions help scientists better understand the processes that cause these events. These surveys are also used by conservation biologists and policy makers to provide measurements of negative impacts on biodiversity.

The problem is that it is difficult to know when the continued absence of a species means that it is extinct. The problem may seem uncomplicated: a species is either still around, or it is not -- what is there to disagree about? Unfortunately, it is not so simple. A species that has not been collected or seen for a long time may be extinct, or it may simply have escaped detection. It is difficult, if not impossible, to prove that the absence of a species (in recent times) is equivalent to its extinction. The best approach is to compile all available evidence that a species is absent, and then decide when the weight of that evidence is sufficient to assume that extinction has occurred.

CREO has developed a research program to determine what sort of evidence should be collected, and how should that evidence be analyzed in order to determine when and why a species went extinct. Data collected through this program has a number of conservation applications that can help us better understand the impact of extinctions on global biodiversity.