Abstract ID: 233

Seasonal Shifts: Amazon Rainforest to Transitional Forests to Cerrado

Amazon transition forest, ecotone, appears to be a gradual blending of the two communities across broad areas at southern part of the humid tropical rainforest and a sharp boundary line in the east occurred from human disturbance. The challenge of vegetation monitoring study in the transition zone is the complexity of their species variation and distribution as well as the physical environment, i.e. a gradient of precipitation and its seasonality. In this study, we focused on how vegetation in the transition zone behaves in response to climate condition, including cerradão, tropical dry forest, and seasonal-flooded transitional forest, and compared to those of the humid rainforest and the cerrado. We used 8-years of MODIS Enhanced Vegetation Index (EVI) data to observe and analyze seasonal dynamics and the shifts across the rainforest-transitional forest-cerrado. TRMM data was utilized for EVI-rainfall relationship analysis. In general, the transitional forests depicted well-pronounced seasonal profiles. However, Instead of green-up at the beginning of the dry season or beginning of the wet season similar to the rainforest and the cerrado respectively, we found significant on shifting in greening-up events (July-August) in the middle (near the rainforest) to the end of the dry season southward to the cerrado. This suggested that the transitional forests represented a mixed response of light, water, and other factors; however, the converted ecotone forests depicted strong, moisture-limited, dry-wet seasonal contrasts due to the dominance of shallow rooted plants that cannot exploit water from deeper soil moisture layers in the dry season. To validate the seasonal patterns from MODIS, the comparison between ground-based eddy flux measurements and remote sensing data is needed. The seasonal shifts transition ecotone forests were unique and will improve parameterization of biosphere-climate models and land cover characterization.

Session:  Carbon - Forest dynamics, natural disturbance, and recovery. (B)

Presentation Type:  Oral