The growth of new trees in Guam has significantly decreased and a non-native snake species is to blame. The brown tree snake is a notorious bird eater and ever since they first came to the Pacific island, they had almost wiped out the population of tree inhabiting birds and like a chain reaction, this has affected new tree growth in the forests as well.
According to BBC, researchers say that the growth of new trees on the island had fallen up to 92 percent and following this unfortunate news are possible long term consequences for the forests of Guam. Birds play a very important role in seed dispersion and reforestation. When birds eat fruit from trees, the fruits' seeds return to the ground through the bird droppings. But since the arrival of the brown tree snake, there has been a great decline in bird population in Guam. In fact, by the 1980s, the brown tree snake has already wiped out 10 of 12 bird species in Guam.
Fruit bats also help in new tree growth but they too have become scarce in the land. To add more bad news, researchers have also tested the natural dispersion process of the forests setting up two 'seed baskets' in two common species of trees. The study revealed that about 10 percent of the seeds are naturally dispersed. Furthermore, these seeds are less than likely to germinate than those seeds that passed through the digestive tracts of bats and birds.
As the bird-eating snakes rise in the forests of Guam, the opposite happens with the bird species. In fact, according to Prof. Haldre Rogers from the Iowa State University, if one happens to come by a forest in Saipan, a neighboring country where so far brown tree snakes are not so rampant, there will be constant chattering of birds. However, the forests in Guam are eerily silent, Phys.org reports.
The study shows how an invasive species can greatly affect island wildlife worldwide. This latest study is also aiming to predict the devastating changes that would occur if people don't find a way to bring the birds back to the land.