Seamark, E. C. J.. 2017. Conserving cave ecosystems and public health. South African Speleological Association. 42: 42-48.
Cave ecosystems are similar to those of oceanic islands, isolated by land instead of water. As with
oceanic islands, they are sensitive to disturbance and effects of invasion by other species. As man
explored, discovering islands, they exploited the local wildlife for food. But in many cases it was what was left behind, that caused more destruction ask the Dodo and its friends?
On the island of Guam (western Pacific), at the end of World War II (1945), scientist started to see a
decline in bird numbers on the island, by the mid-1980’s eleven bird species were extinct. Many
theories surrounded the extinction of these birds, ranging from testing of chemical weapons to
typhoons. Eventually the culprit was identified; a snake (Boiga irregularis). Probably introduced onto
the island as a pet or transported as part of cargo unintentionally, during WWII. Having no natural
predators on the island, these snakes increased steadily in number, having an abundant supply of bird
chicks to eat. While the birds on the island having never encountered a snake before, did not have any
defensive strategies in place to prevent their chicks from being eaten. As no new birds were surviving to adult hood (or very few), eventually the older birds became too old to reproduce and died extinction of species.
There are many examples where introduced species have or are causing the extinction ….