Analysis of the streamside vegetation within the Hubbell Trading Post National Historic Site, Apache County, Arizona

Baker, Marc

Foliar height density of perennial vascular plants and percent cover of annual vascular plants were estimated for the riparian vegetation along Pueblo Colorado Wash within the boundaries of the Hubbell Trading Post National Historic Site, Apache County, Arizona. Data were recorded as a baseline for assessing changes in vegetation over time. Two sets of transects were established. One set was established along the south bank of the intermittent stream, where there had undergone efforts to eradicate the exotic shrubs, Elaeagnus angustifolius (Russian-olive) and Tamarix ramosissima (salt-cedar). The other set of transects was established along the north bank, where there had been no treatment. Both sets of transects were measured in mid-July and transects within the treated area were remeasured in late September. Foliar height density, of woody vegetation, including that for seedlings, was very low within the treated area. There were no apparent differences in perennial vegetation between the summer and fall transects. Woody vegetation within transects of the untreated bank was dominated by E. angustifolius and T. ramosissima, while Populus deltoides (Eastern cottonwood) was common. Eleacharis parishii (parish spikerush) and Scirpus pungens (common three-square) were the dominant herbaceous perennials and Xanthium strumarium (cocklebur) was the dominant annual. Along the dry banks within the treated area, percent cover of annuals increased dramatically from summer to fall.