Research Technical Report

Using Geographic Information Systems (GIS) to Analyze Kelp Fluctuations in the Monterey Bay National Marine Sanctuary

Osiadacz, M.H., A.A. Guest, and S. DeBeukelaer (April 2008)

Poster presentation at the 2008 Sanctuary Currents Symposium, Seaside, CA

ABSTRACT

Using GIS The Monterey Bay National Marine Sanctuary (MBNMS), one of the world's most productive marine ecosystems, supports extensive kelp forests. Kelp surface canopies are present along almost the entire sanctuary, but the size and diversity of these resources vary from year to year due to a variety of complex environmental influences. To reduce negative impacts and help manage kelp ecosystems, it is necessary to accurately assess canopy coverage in large areas over long periods of time. ArcGIS is an effective tool that provides a method to objectively determine kelp coverage using aerial imagery of coastal kelp resources within the sanctuary. Infrared images of the kelp canopy from 1999 and 2000 were geo-referenced using ArcGIS 9.2. Then the signature of the kelp was extracted as a feature, and the canopy surface area, spatial extent, and relative density index determined. The data derived from these layers may be integrated with GIS layers developed by the California Department of Fish and Game from surveys conducted in 1989, 1999, and 2002-2005, and used to update the persistence and total extent kelp layers. The new spatial datasets can be integrated with other GIS layers to explore biological, chemical and physical factors that impact kelp resource fluctuations. In addition, this analysis can provide a historical perspective that will help examine the effects of human induced climate change on kelp forests and provide a baseline for research in the newly adopted Marine Protected Areas.