Nutrients across an ecosystem
Vitousek studies nitrogen and phosphorus in soils, litter, forests and agricultural systems, including changes caused by people. His interests also include improving fertilizer efficiency, connecting biogeochemical processes with the environmental consequences of production.
Comparing substrates of different ages
His group and collaborators developed a Long Substrate Age Gradient across Hawai‘i, using the generally increasing age of volcanoes from southeast to northwest. Six sites range from about 300 to 4.1 million years old, providing comparisons of soils and ecosystem development; several researchers contributed to this sequence.
References: [2]
Invasion changes processes
The group studied how invasive grasses alter fire frequency and suppress native forest recovery. An introduced nitrogen-fixing tree can also change soil nutrients and facilitate other non-native plants, illustrating how newcomers modify conditions for subsequent community change.
References: [2]
Land, culture and sustainability
Vitousek and collaborators also examine precontact Hawaiian dryland and irrigated agriculture to understand long-term interactions between people and environments. Their outreach includes local audiences and Native Hawaiian communities, bringing historical land-use evidence into contemporary discussions.