PARENT SESSION
Contributed Oral Session 66: Disturbance Ecology : Water, Wind, and Ice
Tuesday, August 9, 1:30 PM - 5:00 PM, Meeting Room 520 B, Level 5, Palais des congrès de Montréal
Greater ice storm damage along terrestrial-aquatic boundaries in forested landscapes.
Kraft, Clifford*,1, Millward, Andrew1, Warren, Dana1, 1 Cornell University, Ithaca, NY, cek7@cornell.edu
ABSTRACT- Ice storms are frequent ecological disturbances in north temperate forest ecosystems, yet have only recently been recognized as having a substantial influence on aquatic systems. The 1998 ice storm was a large-extent ecological disturbance that damaged forests throughout northeastern North America, producing widespread wood deposition on the forest floor and in streams. In this study we evaluated the potential for increased tree canopy damage along the naturally occurring forest edges adjacent to streams and lakes. Forest vigor and canopy density were compared before and after the 1998 ice storm using a digital change analysis comparing the normalized difference vegetation index (NDVI) in atmospherically corrected satellite imagery of the Adirondack region (New York, USA). Forest damage was separated from natural variations in canopy reflectance by employing a generalized linear model that incorporated in situ measurements. The discontinuities in forest canopy closure created by lakes and streams were hypothesized to increase tree susceptibility to icing, wind exposure, and subsequent breakage. An incremental buffering procedure was implemented within a GIS to test this hypothesis proximate to these stream and lake edges. Where icing was severe and broad in spatial extent, no significant difference in forest canopy damage was found along terrestrial-aquatic boundaries compared with surrounding forest locations. In locations where icing was lower in intensity, forest edges along streams and lakes were significantly more susceptible to ice storm damage. Forest susceptibility to an ice storm edge effect was also found to vary with stream width. These results substantiate the influence of ice storm disturbances upon aquatic ecosystems within forested landscapes and highlight the importance of the aquatic-terrestrial boundary to both forest and aquatic ecosystems.
Key words: Ice storm, Disturbance, Terrestrial-aquatic boundary, Edge