THE RELIABILITY OF VEGETATION INDEXES FOR MONITORING SALT-MARSH VEGETATION COVER

The dynamic nature of saltmarshes poses a challenge for coastal zone m onitoring; natural variability in the sediment reflectance and atmosph eric visibility within saltmarsh environment affects the reliability o f regression relations between vegetation cover and vegetation indices . Analysis of field data indicates that regression equations should on ly be applied to sparse canopies. Mixture modelling and signal-to-nois e analysis show that resistance to sediment reflectance variability is more important than resistance to atmospheric visibility changes. The refore MSAVI and GEMI are the best indices to use for saltmarsh vegeta tion cover monitoring.