Tinaja and hanging garden vegetation of Capitol Reef National Park, southern Utah, U.S.A.

Abstract

The vegetation and flora of 22 tinajas (bedrock depressions filled with water) and six hanging gardens in Jurassic age Navajo Sandstone in the Waterpocket Fold, Capitol Reef National Park, were investigated. Tinajas supported more species than the hanging gardens, and included riparian obligates like Phragmites australis, Typha latifolia, and species of Juncus and Salix. Significant floristic differences were found between tinajas and hanging gardens. A relatively widespread flora existed among tinajas in adjacent drainages, but high species turnover occurred between tinajas from more distant drainages, suggesting different source floras or climatic factors. Vegetation patterns among tinajas were related to pool size and protection from the sun. Ordination endpoints were formed by deep, more or less permanent tinajas and shallow, ephemeral tinajas. Dispersal spectra were different between tinajas and hanging gardens, with the latter supporting more species with long-distance wind dispersed species. Overall, the riparian flora of both tinajas and hanging gardens included a significant number of such species, while those adapted to animal dispersal were significantly under-represented.