Classification Of Vascular Plant Communities Of The North Cascades Using Discreet Space Boundary Analysis
|George Wooten and Peter Morrison
Published as an open file report by Floradora Farms, Twisp, WA 2006+
Plant communities in the North Cascades Mountain Range of Washington respond to a broad range of environmental factors, spanning 11.7 SD of species turnover across the primary axis of variation. Vegetation types encompassing maximum satellite spectral and geographic representation across the North Cascades were sampled and 1433 detailed plots were selected for further analysis. These plots were aggregated into composite sample sets using their mean abundance values. The composite samples were partitioned into discreet regions on color-coded scatter plots of the detrended correspondence analysis ordination space, bounded by minimum surfaces along indicator species gradients. The set partitions were then defined by a rule-based sequential filter that separated plots by the abundances of differential plant species. The inequalities which defined the rules formed a dichotomous classification of 14 major sets of North Cascades plant communities. These data sets and their classification keys were compared with other classification systems used in the Pacific Northwest in a classification concordance. The primary ordination axis spanned 11.7 SD and was aligned along an east-west gradient. The secondary ordination axis spanned 6.9 SD, aligned along a wet-dry gradient. Approximately 4 SD represents a complete species turnover, i.e., the ordination distance in which none of the same species occur in the plots. Thus, the primary axis of this data represents approximately 3 complete community turnovers in going from east to west across the North Cascades.
Keywords. Relevés, ordination, heirarchical classification, detrended correspondence analysis, reciprocal averaging, ground truthing, spectral classes.
Published online and copyright 1993 onward at:
The following files were developed in conjunction with the North Cascades Grizzly Bear Ecosystem Mapping Project. The raster geospatial database is available from Washington Department of Wildlife. These files can be downloaded from this web folder. Files are briefly described below.
1. Allplots.db (Plant association data; for documentation, see allplots_datadct.pdf)
2. Extg.db (Plot data; for documentation, see extgdb_datadct.pdf)
3. ncas-eco-databases.zip (Plot data in Paradox DB format; readme file included)
3. Grz_asn_u10_83.zip (shapefiles with plant association data; for
documentation, see Arcview_creation.pdf)
Created from grzstand.db (grzstan2) + grzasso.db
4. Grzextg_u10_83.zip (shapefiles with plot data; for documentation, see
Created from allplots.db + extg.db
5. Grzsp_u10_83.zip (shapefiles with plant species data; for documentation,
Created from grzspall (grzspal2, grzspal3, grzsp) + grzcode + allplot2 (for coordinates)
6. Grzcode.db - Plant names by alphacode
- Almack, J.A., W.L. Gaines, R.H. Naney, P.H. Morrison, J.R. Eby, G.F. Wooten, M.C. Snyder, S.H. Fitkin, E.R. Garcia (1993). North Cascades Grizzly Bear Ecosystem Evaluation. Report to the Interagency Grizzly Bear Committee in fulfillment of requirements identified in the 1982 Grizzly Bear Recovery Plan.