Species interactions and ecological function under biodiversity loss and climate variability

University Of Montana, Missoula MT

Investigators

Abstract

Forests are vital to the health of our planet, providing clean air, fresh water, and a variety of other benefits to humans. They are also home to a vast array of plant and animal life, all of which play important roles in maintaining the balance of the ecosystem. Like all ecosystems, however, forests are increasingly threatened by biodiversity loss and climate change. Though these changes can disrupt the complex interactions among species that make forests function properly, we still have a limited understanding of these cascading impacts. This study takes advantage of a unique natural experiment to investigate how the loss of a key species – the bearded pig – affects the health of a tropical rain forest in Borneo. The bearded pig was once a common animal in this ecosystem, playing a vital role in seed predation, herbivory, and nutrient cycling, but was recently wiped out by an introduced disease. This project will use a combination of field observations, experiments, and modeling to understand how the loss of bearded pigs has affected the ecosystem. Research results will be disseminated to non-governmental organizations and policy-makers involved in biodiversity assessment and conservation. The project will also generate outreach materials to educate the public and K-12 students about ecological functions and how they are affected by global changes. Specifically, the research has three main objectives. First, it will assess how the loss of bearded pigs affects the survival and growth of tree seedlings. Pigs played a key role in tree regeneration by eating the seeds of many plant species. Researchers will repeat a number of exclosure experiments conducted when pigs were abundant to determine how pigs and other seed-destroying consumers like rodents, insects, and fungi affect seed fates, and whether these other groups compensate for the lost effects of pigs. This will help elucidate how extirpation of an important mammal species affects the regeneration of multiple tree species. Second, the research will determine how the loss of bearded pigs and climate change combine to affect the amount of carbon stored by the forest over time. By affecting regeneration of large trees with high wood density more than other types of trees, bearded pigs are thought to have influenced overall forest carbon storage in ways that are now changing after the species’ loss. Such ecosystem changes might become even more severe as the forest starts to experience more frequent and severe droughts. Using integral projection models parameterized with extensive observational and experimental data, researchers will examine the population trajectories of numerous tree species that vary in adult size, wood density, and other traits important for carbon storage. Finally, the research will ascertain how the loss of bearded pigs affects other animals in the forest. Pigs were an important food source for predators like clouded leopards, they competed with other herbivores like deer for food, and they potentially even affected birds and bats by competing with (and reducing the abundance of) seed-eating insects. Using occurrence and abundance data spanning the last decade, researchers will examine whether the loss of pigs is changing the abundance of these other important animals in the rain forest. This project is jointly funded by Population and Community Ecology, the Established Program to Stimulate Competitive Research (EPSCoR), and Ecosystem Sciences. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.