Correlating peak NDVIS of salt marshes with environmental conditions in Louisiana, USA, using principal component analysis

Salt marshes, inhabiting a narrow portion of the intertidal zone, are vulnerable to various environmental alterations related to climate change. We model Louisiana salt marshes phenology from 1984-2011 using moderate resolution multispectral remote sensing data (i.e. Landsat imagery). Peak Normalized Difference Vegetation Index (NDVI), as an indicator of peak biomass, did not show any significant temporal trend. The annual temperature, sea-level, and atmospheric CO₂ concentration increased over time, while the annual precipitation shows no temporal trend. Four principal components are calculated from the original environmental variables (what are these?), but r, none of them was significantly correlated with the peak NDVIs. Therefore, it may be concluded that although the marshes´ habitat is climatic-sensitive, their peak NDVIs are resilient to climate change. The long-term record of the salt marsh peak NDVI may serve as a baseline for examining effects of other disastrous events.