LTER: Luquillo LTER VII: Understanding Ecosystem Change in Northeastern Puerto Rico

About This Grant

The Luquillo Long-Term Ecological Research Program (Luquillo LTER) studies how environmental variability, such as more severe hurricanes and droughts, affect the tropical forests in the Luquillo Mountains in eastern Puerto Rico, USA. Since the Luquillo LTER began in 1988, multiple hurricanes and droughts have affected the site. This research looks at how ongoing changes in disturbance patterns and what has happened in the past could lead to new combinations of forest plants and animals. For example, species adapted to hot and dry conditions might expand into tropical forests where trees have been blown down following hurricanes. The program includes exciting experiments to investigate how increased droughts could change which plant and animal species remain in these forests and how carbon and nutrients are stored in the soil and streams. The Luquillo LTER helps train the next generation of scientists, with student engagement from elementary to graduate levels. The Luquillo Long-Term Ecological Research Program (LTER) combines long-term measurements, experimental manipulations, and computer simulations to determine the effects of changes in the frequency and intensity of disturbance events on tropical forests. Building on a 90-year research history in natural and modified forests, research at this site has revealed that while tropical forests exhibit resilience to individual disturbance events, the potential combination of increased frequency of intense storms and more frequent drought may compromise ecosystem resilience in the long-term. This research tests hypotheses that changing environmental and disturbance regimes, interacting with the effects of past disturbance events, will result in new combinations of species and altered biogeochemical dynamics. The research will continue to characterize the spatial and temporal dynamics of biota and biogeochemical processes in native tabonuco forest and leverage temperature variation across elevation in the Luquillo Mountains for the purposes of field experiments. Two experiments, simulating drought and warming, will address hypotheses that increased drought frequency will alter species composition and distribution as well as soil carbon and nutrient storage along hill slopes and in streams. Computer models and data-model integration will provide predictive understanding of the combined effects of increased drought and hurricane frequency on tropical forests, as well as facilitate synthesis across scales and forecasting of future ecosystem states. The Luquillo LTER will continue to train undergraduate and graduate students, as well as secondary school students and teachers, producing a cadre of new multidisciplinary scientists who have the skills and experiences to address the pressing environmental challenges of the 21st Century. 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.