Continuous 1985–2012 Landsat Monitoring to Assess Fire Effects on Meadows in Yosemite National Park, California

Remote Sensing

Christine M. Albano¹  Miguel L. Villarreal²  Christopher E. Soulard²  Jessica J. Walker² 

[1] John Muir Institute of the Environment, University of California, Davis, CA 95616, USA;US Geological Survey, Western Geographic Science Center, 345 Middlefield Road, MS-531, Menlo Park, CA 94025, USA;

关键词: wildfire;    meadow;    vegetation change;    NDVI;    Google Earth Engine;    Landsat;    Sierra Nevada;    Yosemite;   

DOI  :  10.3390/rs8050371

来源: DOAJ

【 摘 要 】

To assess how montane meadow vegetation recovered after a wildfire that occurred in Yosemite National Park, CA in 1996, Google Earth Engine image processing was applied to leverage the entire Landsat Thematic Mapper archive from 1985 to 2012. Vegetation greenness (normalized difference vegetation index (NDVI)) was summarized every 16 days across the 28-year Landsat time series for 26 meadows. Disturbance event detection was hindered by the subtle influence of low-severity fire on meadow vegetation. A hard break (August 1996) was identified corresponding to the Ackerson Fire, and monthly composites were used to compare NDVI values and NDVI trends within burned and unburned meadows before, immediately after, and continuously for more than a decade following the fire date. Results indicate that NDVI values were significantly lower at 95% confidence level for burned meadows following the fire date, yet not significantly lower at 95% confidence level in the unburned meadows. Burned meadows continued to exhibit lower monthly NDVI in the dormant season through 2012. Over the entire monitoring period, the negative-trending, dormant season NDVI slopes in the burned meadows were also significantly lower than unburned meadows at 90% confidence level. Lower than average NDVI values and slopes in the dormant season compared to unburned meadows, coupled with photographic evidence, strongly suggest that evergreen vegetation was removed from the periphery of some meadows after the fire. These analyses provide insight into how satellite imagery can be used to monitor low-severity fire effects on meadow vegetation.

【 授权许可】

Unknown