Hydrological feedbacks between phosphorous deposition and canopy cover in dry seasonal forests

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

Large areas of tropical forests are vulnerable to both anthropogenic and natural disturbances, and important issues determining their sensitivity to disruption must be addressed to gain improved management practices. One of these is how changes in land-use or tropical storm patterns affect the resiliency of phosphorus-limited Neotropical forests where vegetation is sustained in the long term by atmospheric phosphorus inputs through rainfall, dust, or fog. Past researchers have found that dust and fog deposition depend on canopy density (leaf area). Canopy traps phosphorus enabling a positive feedback between vegetation and phosphorus deposition. This study is investigating the ecohydrological mechanism controlling the occurrence and strength of these feedbacks and their susceptibility to changes in climate and land cover. The principle objectives are: 1. To quantify the total phosphorus input from deposition to a dry neotropical forest and to investigate its fluctuations between dry and wet seasons, associated with fires, and proximity to ?slash and burn? management. 2. To quantify the dependence of phosphorus deposition on canopy properties and thus the strength of the canopy-phosphorus deposition feedback. 3. To determine the relative magnitudes and roles of rainfall, dust, and canopy condensation in total phosphorus input. These three processes are differently affected by changes in climate and land cover. Students will be trained and teaching materials developed for use in protecting these sensitive ecosystems.