U S Department of the Interior

Landsat-based Monitoring of Landscape Dynamics at Apostle Islands National Lakeshore, 2004-2009 U S Department of the Interior

Publisher Marketing: Apostle Islands National Lakeshore (APIS) is composed of a group of 21 islands in western Lake Superior and part of the Bayfield Peninsula of northern Wisconsin. Disturbances, or distinct changes in vegetation cover, are an important part of how this ecosystem functions. Monitoring these disturbances through time will provide information regarding historic disturbance regimes compared to present and future conditions and trends. For this analysis, disturbances in and around APIS were delineated for six years, 2004-2009, using a combination of Landsat satellite imagery and high resolution aerial photos. A set of computer algorithms were employed (LandTrendr), in conjunction with a dense time series of Landsat imagery (one set for each year) to track vegetation changes in and around the park. LandTrendr was used to identify apparent disturbances, after which high resolution imagery (airphotos) was used for photo interpretation to substantiate evidence of a disturbance, and hence, validate whether the disturbance occurred. For each validated disturbance, we identified the agent of change (fire, forest harvest, development, flooding due to beaver activity, and blowdowns) in addition to the year of occurrence, and starting and ending vegetation classes.