A direct gradient analysis of montane vegetation in the Toiyabe Range, Nevada

Canonical correspondence analysis (CCA) was utilized to model variation in community composition and structure relative to environmental gradients including: elevation, slope, soil texture, soil pH, available nitrogen, available phosphorus, and available potassium. Data were collected in Nevada's Toiyabe Range, a southwest-northeast trending fault-block range in the central Great Basin. A survey of 43, 400m2 macroplots and 86, 1m2 nested microplots was conducted on the west slope of the Toiyabe Range during the months of June, July, and August 1999, and August 2000.; Within the ordination model, seven non-discrete woodland and shrubland assemblages were characterized in relation to interspecific and species-environment interactions. Gradients contributing significantly (p ≤ 0.05) to the ordination include: elevation, slope, percentage of sand in the mineral substrate, and soil pH. The CCA model illuminates numerous associative and mutually-exclusive interactions among montane taxa in relation to dominant environmental gradients, and provides an informational basis for future investigations.