Birds in forest systems eat insects and consume fruit, dispersing seeds throughout the forest. If birds are critical to the functioning of a healthy forest, then the current global decline in birds may lead to a domino effect, causing the breakdown of forests worldwide. This study aims to determine the importance of birds to forest communities using a natural experiment: the research compares patterns in seed dispersal and control of insects between the island of Guam, where all birds have been functionally extirpated by the invasive Brown Treesnake, and the islands of Saipan, Tinian and Rota, which have relatively healthy bird populations. Techniques used will include seed trapping, seed and seedling additions to simulate dispersal and experiments in paired areas with and without birds (where netting is used to keep out birds).
The research addresses basic ecological questions including whether dispersal is important for determining forest tree species diversity and whether insectivorous birds can control insect populations in forest systems. Given that forest products provide hundreds of billions of dollars to the global economy each year, and insects are the largest pests and vectors of disease, the results from this work will inform management from local to global scales.
