PARENT SESSION
Oral Session - Modeling Species Patterns Chair(s): Bossenbroek, Jonathan¹, ¹ University of Notre Dame, Notre Dame, IN
Friday, April 2, 2004 3:00 PM - 5:20 PM Apollo Room 5

Scale, pattern and controls of montane ecotones. ^*KUPFER, JOHN , ¹ Dept. of Geography and Regional Development, Tucson, AZ, USA

ABSTRACT- Abiotic conditions, biotic processes and relationships, and disturbance form a complex and often complicated relationship that influences vegetation pattern and montane ecotone location. The abrupt changes in climate and vegetation in the Santa Catalina-Rincon Mountain complex of southeastern Arizona provide an ideal setting in which to examine not only the effects of these factors on ecotone location but also how ecotone locations are related to differing variables at different spatial scales and resolutions. The purpose of this study was to better understand montane ecotone patterns by linking GIS, remote sensing, and multivariate statistical analysis to relate ecotone location to abiotic influences and disturbance history. Plant community distributions were mapped using a classification of Enhanced Thematic Mapper imagery. Training and test data were assembled through field data collection and photointerpretation, and a range of topographic indices (e.g., slope, aspect, slope position) were mapped using a 30m digital elevation model. Fire disturbance history for the study area was reconstructed from fire perimeter maps dating back to the 1940's that were provided by forest managers at Saguaro National Park. The relationship between ecotone locations and independent predictor variables was assessed using multinomial logistic regression and predictive vegetation modeling for three different scales, ranging from site- to landscape-level. Results of our analyses indicated that: 1) both abiotic conditions and time since fire were important in shaping current ecotone patterns and 2) fine-scale ecotone patterns were correlated to a different set of variables than coarse-scale patterns.

KEY WORDS: sky island, ecotone, forest pattern, arizona