The Hawaiian Islands are a unique place. Strange birds, tropical fish, migrating whales. However in recent centuries many non-indigenous animals have started to take over the islands. These animals have a big impact on the biodiversity in the area, but recent analysis says that Hawaii’s unique animals and plant life have been declining for long before the introduction of non-native species—in fact the University of California, Berkley says that the native life has been declining for millions of years.
Shrinking land areas of the older islands puts stress on the life there. The only island growing is the big island after all, so the rest are giving less and less space to the various birds, insects, spiders, and plants there (there are no native mammals on the islands). At a certain point this means extinction.