There have been done a lot of studies on threatened and extinct species in Singapore. It’s important to know that at least 90% of the forests were cut before plant and animal collection began in the end of the 19^th century. Because of this there’s a big change that some species became extinct before collection of flora and fauna started.

‘It’s important to know that at least 90% of the forests were cut before plant and animal collection began in the end of the 19^th century’

A way to estimate extinctions is to compare two species lists. If a certain species only occurs on the old list and not on the newer list, than you can conclude that a species has gone extinct. Castelletta, Sodhi and Subaraj (2000) compared for example bird checklists from 1923 and 1998 and they found that in those 75 years 65 out of 203 bird species have became extinct in Singapore.

In historical times with less available data of species in Singapore this is more difficult to do. In that case researchers can use checklists of very similar habitats in Malaysia’s adjacent Peninsula.

 

 

An important factor in this field of research is doing estimations about future extinctions. To predict the effects of habitat exhausting on species diversity researchers use the following species-area equation (A_new/A_original)^Z . ‘A’ refers to the proportion of an area available to species. ^‘Z’ is a derived constant, for tropical climates researchers use 0.25.

Although extinctions are very difficult to measure with certitude, the intensively sampled area of the remaining small forest has as consequence that measurements include not many false negatives. A false negative would occur if a researcher claims that a species has not gone extinct if that species actually has gone extinct. This is probably the only beneficial consequence of having a little forest.