PARENT SESSION
Poster Session #18: Remote Sensing and GIS.
Tuesday, August 7, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall
95
Detecting contrasting patterns of photosynthetic activity in arctic vegetation using remote sensing.
HOUSTON, STAN1,2, GAMON, JOHN1,2, HUEMMRICH, KARL2,3, 1 2 3
ABSTRACT- The objective of this study was to assess the photosynthetic physiology of the three main cover types (vascular plants, mosses, and lichens) in a tundra ecosystem at Barrow, Alaska using remote sensing techniques. To test this approach, reflectance measurements were made at a small scale (~10 cm patches) using a portable spectrometer. The three cover types exhibited contrasting reflectance spectra. Of the three groups, lichen spectra were the most distinct, largely due to their pigment composition, which contrasted strongly with that of the vascular plants and mosses. Vascular plants showed a strong seasonality in NDVI (Normalized Difference Vegetation Index, a measure of canopy greenness derived from reflectance), while mosses and lichens did not. NDVI was also strongly correlated with independent measures of photosynthetic activity (gas exchange and chlorophyll fluorescence), indicating that NDVI is linked to the photosynthetic performance of species in this ecosystem. Overall, these findings support the ability of remote sensing to detect contrasting seasonal patterns of physiological activity in these different arctic cover types.
KEY WORDS: remote sensing, gas exchange, arctic