Numata, Izaya: South Dakota State University (Project Lead)
Cochrane, Mark: University of Maryland (Co-Investigator)
Kjaersgaard, Jeppe: South Dakota State University (Co-Investigator)
Project Funding:
2014 - 2017
NRA: 2013 NASA: Terrestrial Ecology
Funded by NASA
Abstract:
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.
This proposal addresses â€Vulnerability and responses of terrestrial ecosystems†,
one of the research topics solicited by the 2013 NASA Terrestrial Ecology Program. We
propose to investigate the vulnerability and responses of forest edges to drought in the
southern Brazilian Amazon that was most severely affected by the recent droughts. Our
approach is the following: 1) determine drought intensity and forest fragmentation
metrics (landscape metrics) across the southern Brazilian Amazon (1998-2014); 2)
conduct field studies of forest edges determined by drought intensity and forest
fragmentation to examine vulnerability and responses of forest edges; 3) generate time
series data of ET and vegetation indices from Landsat to assess regional canopy
desiccation and its recovery from drought impacts; and 4) predict the future vulnerability
of forest edges to drought based upon simulated future climate and land cover change
scenarios.
Publications:
Khand, K., Numata, I., Kjaersgaard, J., Vourlitis, G. 2017. Dry Season Evapotranspiration Dynamics over Human-Impacted Landscapes in the Southern Amazon Using the Landsat-Based METRIC Model. Remote Sensing. 9(7), 706. DOI: 10.3390/rs9070706
Numata, I., Khand, K., Kjaersgaard, J., Cochrane, M., Silva, S. 2017. Evaluation of Landsat-Based METRIC Modeling to Provide High-Spatial Resolution Evapotranspiration Estimates for Amazonian Forests. Remote Sensing. 9(1), 46. DOI: 10.3390/rs9010046
Numata, I., Silva, S. S., Cochrane, M. A., d'Oliveira, M. V. 2017. Fire and edge effects in a fragmented tropical forest landscape in the southwestern Amazon. Forest Ecology and Management. 401, 135-146. DOI: 10.1016/j.foreco.2017.07.010
2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)
- Assessing vulnerability and responses of forest edges to drought in the Brazilian Amazon
-- (Izaya Numata, Mark A. Cochrane, Jeppe Kjaergaard, Kul Khand, Sonaira Souza Silva)
[abstract]
More details may be found in the following project profile(s):
