Recent severe droughts in Amazonia (2005 and 2010) have led to extensive damages to forest canopies and increased rate of tree mortality. After the 2005 drought, considered a once in century extreme event, the Amazon forest experienced another even more severe and extensive drought in 2010, with more than 600,000 km2 of forest area affected by both droughts. In addition to drought, the Amazon forest has been disturbed by deforestation over the past decades, and remnant forests are continuously fragmented into smaller habitats. Fragmented forests suffer several biological and ecological changes due to edge effects, including desiccation, that exacerbate regional forest degradation. As of 2010, 34% of the remaining forest outside protected areas is within 1 km of forest edges in the Amazon Basin, but much larger proportions are found in highly fragmented regions such as Rondônia (> 90%). Drought impacts should be larger and more severe in fragmented forest landscapes, especially within forest edges that dry more rapidly and intensely, however, the spatial scale of this phenomenon has not yet been quantified. As more frequent and intense extreme drought events are predicted in the future, more severe and extensive damages in regional ecosystems are expected as the remnant forests become increasingly fragmented with future land cover change in the Amazon. In this context, forest edges may serve as early warning indicators of potential tipping points at which climate change-triggered drought conditions could cause serious ecological changes to Amazonian ecosystems.
Project members:
- Dr. Izaya Numata (PI): Geographic Information Science Center of Excellence (GIScCE)
- Dr. Mark Cochrane: GIScCE, SDSU
- Jeppe Kjaersgaard: Water Resources Institute, SDSU
- Sonaira Souza da Silva: Universidade Federal do Acre, Brazil
This project is supported by the NASA Terrestrial Ecology research program.
(Grant # NNH13ZDA001-TE)