About This Project

Although the diverse and colorful Hawaiian tree snails have been studied for many decades, the potential ecological role played by tree snails has only been the subject of speculation, and has never been scientifically addressed. We've recently confirmed that these arboreal snails graze on microbial biofilms that grow on host tree leaves, depositing feces, which wash down to the forest floor in frequent rain showers. Could this provide important natural fertilizer for the trees themselves?

Ask the Scientists

What is the context of this research?

The Pacific Islands can be considered an environmental microcosm of what is occurring on a global scale. Hawaii and other islands harbor sensitive native marine and land ecosystems that provide important air, water, and nutrient cycling services for human populations. In fact, people living in the tropics rely directly on native rain forests for abundant clean water, as intact forest ecosystems act as upland reservoirs, capturing and slowly releasing clean water. But natural ecosystems are being degraded globally at an alarming rate. In many cases, one of the drivers is release and establishment of nonnative plants and animals. In no place is this more evident than on islands, where accidental and intentional release of nonnative species wreak havoc on naïve, native organisms.

What is the significance of this project?

Considerable effort is currently being dedicated to protect and maintain the rare Hawaiian tree snails by government agencies as well as university researchers. But unfortunately, invasive predators are having a major impact on the survival of the tree snails: we have lost about 75% of the 100 species in recent decades. Nonnative predators include the wolf snail, rats and Jackson’s chameleons (see lab notes for photos). Therefore we seek to raise public and scientific awareness thru an understanding of the role of tree snails in Hawaiian forests, without which, justification of work to save them is challenging, in terms of public understanding as well as perception. We hope to generate data to allow us to say definitively what the snails provide to the tropical rain forest.

What are the goals of the project?

The goals of this study include obtaining both qualitative and quantitative information about potential differences in the nutrient environment between intact rain forests where the diverse native tree snail fauna is present, versus the increasingly common forest areas where the snails have been wiped out by nonnative predators. Our methods in this comparative study will include rinsing cages that contain only native plants, versus cages with known numbers and size classes of snails, present for known time intervals, collecting and analyzing organic chemical content of the waste, and comparing the results. Our goal is to show detailed analysis breakdown of organic nutrients nutrients in rain washed trees with snails and without snails present.