A Floristic Analysis of Neoglacial Deposits in the Teton Range, Wyoming, U.S.A.

Abstract

The flora of Neoglacial till at 12 sites in the Teton Range, Wyoming, was investigated. Ten sites are moraines fronting glaciers, one is a moraine fronting a neve patch, and one is a rock glacier. A total of 109 species of vascular plants were collected. Only seven species were found at all sites. Most species were found at only a few sites, with 25% restricted to a single site. Comparisons between the flora on Neoglacial deposits and two hypothesized source floras indicated that no significant differences exist with respect to propagule dispersal type or phytogeographic distribution. Species richness ranged from 17 to 68 species per site. Sites which were adjacent or in the same canyon were significantly more similar to each other floristically than more distant sites. Rank correlation of species richness with six site variables showed that the type of vegetation, including alpine meadow, subalpine meadow, streamside, talus, and timberline forest, which surrounds each site had the strongest correlation with species richness. Topographic diversity of site deposits and aspect also showed significant correlations with species richness. Site elevation, deposit area, and deposit age were not correlated with species richness. Detailed floristic studies on dated deposits of differing age indicated that floristic and vegetational relationships change little over time, perhaps because of extensive mass wasting on the Neoglacial deposits.