Hurricanes,people, and riparian zones: controls on nutrient losses from forested Caribbean watersheds

Studies of nutrient cycling in tropical forests have shifted and broadened their focus in the past 20 years. Early research highlighted the tight retention of nutrients (primarily P) in the soil profile, and the effects of slash and burn agriculture on nutrients in soil and soil water. More recent work includes a wider variety of experimental approaches, nutrients, and disturbance types. Using examples from my own research and from the literature, I examine the impact of catastrophic natural disturbance, human land use, and landscape features near the stream channel (riparian and hyporheic zones) on nutrient losses from tropical forests. These studies show that the effects of catastrophic natural disturbance can be ephemeral, that impacts of human land use can greatly exceed those of natural disturbance, and that landscape features can play a very important role in minimizing nitrogen losses from humid tropical catchments. Future directions for research in tropical forest nutrient cycling are suggested.