Comparison of Phreatophyte Communities on the Rio Grande in New Mexico
1964
Campbell, C. J. | Dick-Peddie, William A.
Randomly spaced line intercepts were taken in 18 relatively mature phreatophyte communities on 300 miles of the Rio Grande in New Mexico. Samples of three stands in each of six geographical areas revealed no regularity in species present, percentages of cover, or height over the entire area. Vegetation of the southern and northern sectors was different. Highly significant differences in tamarisk (Tamarix pentandra) and screwbean (Prosopis pubescens) cover were found in plots within areas. The difference in cottonwood (Populus fremontii) cover within and between plots where cottonwood dominated was nonsignificant. No correlation could be found between pH, total soluble salts, and texture of the soil and dominant species of plants growing in the area. In general, no distinct breaks or ecotones occurred in the composition of the narrow band of river vegetation; it formed a continuum with gradual and almost imperceptible changes between dominant and subdominant species as one moved north or south. Postclimax vegetation has been altered or modified in many areas to produce quasi—permanent or disclimax vegetation. Five classes of phreatophyte vegetation were arbitrarily established, the lowest development consisting primarily of screwbean in the southern sector and the highest of dominant cottonwood above San Antonio, New Mexico. The introduction and escape of tamarisk and Russian—olive (Elaeagnus angustifolia) in the last 50 years have changes the successional stages and ultimate dominants of some communities.
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