Seagrass or submerged aquatic vegetation (SAV) is a valuable and abundant resource found within the Gulf Islands National Seashore of Florida and Mississippi. Seagrass provides habitat for aquatic species such as lobsters, crabs, shrimp, fish, and manatees. It has been estimated that over 50% of the total seagrass coverage in the United States is found in the Gulf of Mexico. Seagrass grows in shallow waters and is therefore prone to damage and erosion from boats, propellers, fishing equipment, and wakes.
The NPS Alaska Regional Office GIS team has been using the newest Satellite Pour l'Observation de la Terre (SPOT) 5 satellite imagery to update hydrography features in the NHD within Denali National Park and Preserve. The NHD is the surface water layer of The National Map, which contains features such as lakes, ponds, glaciers, streams, rivers, canals, dams and stream gages. Much of the current NHD in Alaska was derived from original USGS topographic mapping based on 1950s aerial photography and compiled at a scale of 1:63,360.
The National Park Service (NPS) Arctic Inventory and Monitoring Network (ARCN) is concerned with understanding widespread ecological changes in the northern Alaskan national parks. Repeat photography is used to document changes in vegetation, water bodies, and certain landforms. The present study compares recent (2008-2010) high-resolution aerial photographs with historical aerial photographs to document changes that have occurred in ARCN over the past 30 years (see figure showing tall shrub increase on tundra).
Warming in the northern high latitudes is expected to alter freeze and break-up dates of lake ice, affecting lake ecosystems, wildlife migration and habitat, human subsistence, and recreation. The Southwest Alaska Network Inventory and Monitoring Program is using daily MODIS satellite imagery to document the dates of freeze-up and ice break-up on lakes in southwest Alaska. The study shows substantial interannual variability in freeze-up dates but the timing of break-up appears relatively constant from year to year.