DISCLAIMER: The data used in this report is fictional and purely for course exercise purposes
Tropical Dry Forests (TDFs) currently occupy 42% of tropical forest ecosystems worldwide but have been reduced to less than half of their historical distribution over the course of the 20th century (Quesada et al., 2009). TDFs are rich in biodiversity and natural resources but with increasing anthropogenic pressure they have quickly become the most threatened tropical ecosystems (Janzen, 1988). Remaining TDFs in the Neotropics are highly fragmented and require state of the art research to guide management decisions (Sanchez et al., 2003). Plant productivity in these semi-arid landscapes fluctuates strongly throughout the year as severe annual drought forces the vegetation into several months of leafless dormancy. My research seeks to characterize TDF growing season patterns, or vegetative phenology, in comparison with meteorological variables that influence water availability in these semi-arid ecosystems in order to assess forest productivity and resilience to micro and meso-scale climate trends.
Using continuous observations of tower-derived vegetative greenness indices and micro-climate wireless sensor networks we track short and long term forest stand growth dynamics as a function of light, temperature and moisture regimes. The quality controlled sensor data is aggregated into seasonal and sub-seasonal climate-canopy state variables and explored using multivariate statistical tools to assess the influence of temperature, humidity, and soil moisture patterns on canopy physiology and overall phenology as indicated by the level of vegetative greenness.
The past decade has seen the warmest temperatures on record in many regions around the globe and a subsequent redistribution of terrestrial moisture regimes (Ponce Campos et. al, 2013). Tropical forests are strongly energetically coupled to the air around them inducing large fluxes in heat, water, and carbon between the Earth's surface and the atmosphere when photosynthetically active. It is important to monitor changing vegetation conditions in order to better assess current atmospheric carbon sources and sinks and develop reliable models for the behavior of these increasingly degraded ecosystems in the near future (Krinner et al., 2005). Exploring the linkages between climate and plant productivity is necessary for proper ecosystem management in the face of accelerating climate and human induced land cover/use changes.
Tropical Dry Forests (TDFs) currently occupy 42% of tropical forest ecosystems worldwide but have been reduced to less than half of their historical distribution over the course of the 20th century (Quesada et al., 2009). TDFs are rich in biodiversity and natural resources but with increasing anthropogenic pressure they have quickly become the most threatened tropical ecosystems (Janzen, 1988). Remaining TDFs in the Neotropics are highly fragmented and require state of the art research to guide management decisions (Sanchez et al., 2003). Plant productivity in these semi-arid landscapes fluctuates strongly throughout the year as severe annual drought forces the vegetation into several months of leafless dormancy. My research seeks to characterize TDF growing season patterns, or vegetative phenology, in comparison with meteorological variables that influence water availability in these semi-arid ecosystems in order to assess forest productivity and resilience to micro and meso-scale climate trends.
Using continuous observations of tower-derived vegetative greenness indices and micro-climate wireless sensor networks we track short and long term forest stand growth dynamics as a function of light, temperature and moisture regimes. The quality controlled sensor data is aggregated into seasonal and sub-seasonal climate-canopy state variables and explored using multivariate statistical tools to assess the influence of temperature, humidity, and soil moisture patterns on canopy physiology and overall phenology as indicated by the level of vegetative greenness.
The past decade has seen the warmest temperatures on record in many regions around the globe and a subsequent redistribution of terrestrial moisture regimes (Ponce Campos et. al, 2013). Tropical forests are strongly energetically coupled to the air around them inducing large fluxes in heat, water, and carbon between the Earth's surface and the atmosphere when photosynthetically active. It is important to monitor changing vegetation conditions in order to better assess current atmospheric carbon sources and sinks and develop reliable models for the behavior of these increasingly degraded ecosystems in the near future (Krinner et al., 2005). Exploring the linkages between climate and plant productivity is necessary for proper ecosystem management in the face of accelerating climate and human induced land cover/use changes.
REFERENCES
Janzen, D.H. 1988. ‘Biodiversity: Tropical dry forests, the most endangered major tropical ecosystem’, National Academies, 130-137.
Krinner, G., N. Viovy, N. de Noblet-Ducoudre, J. Ogee, J. Polcher, P. Friedlingstein, P. Ciais, S. Sitch, and I.C. Prentice. 2005. A dynamic global vegetation model for studies of the coupled atmosphere-biosphere system. Global Biogeochemical Cycles, 19: GB1015.
Ponce Campos et. al. 2013. Ecosystem resilience despite large-scale altered hydroclimatic conditions. Nature, 494: 349-352.
Quesada, M, G.A. Sanchez-Azofeifa, M. Alvarez-Anorve, K.E. Stoner, L. Avila-Cabadilla, J. Calvo-Alvarado, A. Castillo, M.M. Espirito-Santo, M. Fagundes, G.W. Fernandes, J. Gamon, M. Lopezaraiza-Mikel, D. Lawrence, L.P. Morellato, J.S. Powers, F.S. Neves, V. Rosas-Guerrero, R. Sayago, and G. Sanchez-Montoya. 2009. Succession and management of tropical dry forests in the Americas: Review and new perspectives. Forest Ecology and Management, 258: 1014-1024.
Sanchez-Azofeifa, G.A., K.L. Castro, B. Rivard, M.R. Kalacska, and R.C. Harriss. 2003. Remote sensing research priorities in tropical dry forest environments. Biotropica, 35: 134-142.