Monitoring postfire succession in the Santa Monica mountains using hyperspectral imagery

摘要

Abstract: The varying fire frequency in the Santa Monica Mountains provides unique opportunities for examining the impacts of disturbance and succession on community composition and ecosystem function at the landscape scale. Fire resets the 'successional clock' of this evergreen-dominated ecosystem and favors early successional annuals that tend to have higher photosynthetic rates and leaf transpiration rates than mature, long-lived woody perennials. Hyperspectral sensors like the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) offer promising opportunities for remotely detecting these dynamic physiological properties in changing landscapes. Specifically, we expect altered photochemical reflectance index (PRI) and water band index (WBI) values for stands in early succession following fire. PRI and WBI from Santa Monica Mountains AVIRIS imagery indeed show complex patterns varying with season and successional state, possibly revealing varying photosynthetic activity in these dynamic, fire-prone landscapes. Further work is attempting to also consider the impact of changing canopy structure and vegetation type on physiological properties detectable with hyperspectral imagery. !23