Present address: Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
Landscape patterns and environmental controls of deciduousness in forests of central Panama
Article first published online: 9 FEB 2010
© 2010 Blackwell Publishing Ltd
Global Ecology and Biogeography
Volume 19, Issue 3, pages 376–385, May 2010
How to Cite
Bohlman, S. A. (2010), Landscape patterns and environmental controls of deciduousness in forests of central Panama. Global Ecology and Biogeography, 19: 376–385. doi: 10.1111/j.1466-8238.2009.00518.x
- Issue published online: 9 APR 2010
- Article first published online: 9 FEB 2010
- environmental gradients;
- remote sensing
Aim Dry season deciduousness affects intra- and inter-annual patterns of carbon, water and energy balance in seasonal tropical forests. Because it is affected by rainfall, temperature and solar radiation, deciduousness may be an indicator of the response of vegetation to climate change. Better understanding of how spatial patterns of deciduousness are affected by climate and other environmental gradients will improve the ability to predict responses to climate change. This study develops remote sensing methods for quantifying tropical forest deciduousness and examines the relationship between deciduousness and environmental factors in semi-deciduous tropical forest.
Location Central Panama.
Methods I applied spectral mixture analysis (SMA) and the normalized difference vegetation index (NDVI) to Landsat images to predict deciduousness which was ground-truthed with field observations of the percentage of overstorey deciduous trees. Using predicted deciduousness from SMA, patterns of deciduousness at three spatial scales were analysed. I determined how deciduousness varied spatially with rainfall and geological substrate.
Results Both SMA and NDVI had strong correlations (r > 0.9) with field observations of deciduousness. On a landscape scale, deciduousness increased as rainfall decreased, but geological substrate altered this relationship. On some geological substrates, deciduousness was much greater than expected for a given rainfall total or showed a slight but significant increase with rainfall. At an intermediate spatial scale, there were highly deciduous patches from 3 to 250 ha in size embedded in non-deciduous forest, which may have resulted from topography, soil variation or past land use.
Main conclusions Dry season deciduousness can be accurately quantified using satellite images indicating that remote sensing can be a valuable tool for detecting change and understanding ecosystem processes in tropical forests from landscape to regional scales.