Monitoring the re-growth rate of alien vegetation after fire on Agulhas Plain, South Africa

[摘要] The Agulhas Plain, an area rich in fynbos, was monitored within six months after the February2006 fire. The potential of using medium resolution imagery, specifically from the ModerateResolution Imaging Spectroradiometer (MODIS) in determining the re-growth rates ofindigenous and alien vegetation types after fire was explored. Pixels representing dense areas ofeach vegetation type were selected. There was a significant difference in the pixels selected foreach vegetation type. A time series of Normalized Difference Vegetation Index (NDVI) datawas derived and fitted to functions, such as Double Logistics and Asymmetric Gaussian asimplemented in the TIMESAT software. The results show that alien vegetation grows fasterafter a fire occurrence than in its absence. Within the specified months of monitoring, it wasobserved that fynbos grew faster than the alien vegetation. Also, the re-growth rates ofvegetation on the coastal soils were higher than those of vegetation on the inland soils. Thedetermination of the re-growth rate was necessary to assist resource managers determine theappropriate time for follow-up of clearing invaded sites after fire.

[发布机构] Stellenbosch University