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University of Arizona (1965)

Survival and spreading ability of endemic and exotic grasses on a desert grassland site

Claverán Alonso, Ramón

Titre : Survival and spreading ability of endemic and exotic grasses on a desert grassland site

Auteur : Claverán Alonso, Ramón,

Université de soutenance : University of Arizona

Grade : Master of Science (MS) 1965

Résumé
A vegetative analysis was made in a desert grassland site near Sonoita, Arizona seeded in 1939 and 1940 to the following native species Bouteloua curtipendula, Bouteloua filiformis, Bouteloua gracilis, Bouteloua hirsuta, and HilaVia belangeri, an^ to the exotic species Andropogon ischaemum, Astrebla elymoldes, Astrebla lappacea, Chloris berroi, Eragrostis curvula, Eragrostls lehmanniana, and Panicum antidotale. The results showed that all the native grasses seeded are present except slender grama (Bouteloua filiformis). The success of the native grass reseeding was difficult to evaluate because it could not be determined whether the plants on the plots resulted from the reseeding or from native plants on the adjacent area. However, curly mesquite (Hilaria belangeri) ranked second in importance (1.8 percent basal density). The only exotic grasses found were Turkestan blue stem (Andropogon Ischaemum) and Lehmann lovegrass (Eragrostls lehmanniana). Turkestan bluestem ranked third in basal density (1.0 percent) in the plots, and was not able to move outside the reseeded area. Lehmann lovegrass ranked first in basal density (2.0 percent) of all species and it increased its original reseeded area about 20 times. Outside the reseeded area it had not spread significantly. Under .the present environmental conditions, Lehmann lovegrass became dominant only when the native sod was disturbed by mechanical means. The seed transporting agents and grazing effects were of secondary importance in its spread.

Mots clés : Grassland ecology — Arizona. ; Desert plants — Arizona. ; Range plants — Arizona.

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Page publiée le 26 janvier 2016, mise à jour le 13 décembre 2017