Date of Award:

1996

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Natural Resources

Department name when degree awarded

Rangeland Resources

Advisor/Chair:

Christopher A. Call

Abstract

Livestock (cattle and sheep) were examined as seed disseminators for reseeding degraded Intermountain rangelands. "Hycrest" crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult. X A. cristatum (L.) Gaert.] seed was fed to yearling Holstein steers and Suffolk ewes. Dw1g was collected from each animal type and deposited on plots of high and low densities of an annual [cheatgrass (Bromus tectorum L.)] and perennial [squirreltail (Sitanion hystrix Nutt.)] grass species. The experiment evaluated the ability of the dung to suppress the resident vegetation, and the recruitment and establishment of Hycrest seedlings emerging from the dung.

Sheep dung had little suppressive effect on resident vegetation and did not provide Hycrest with a favorable microsite for germination and establishment. Cattle dung provided favorable conditions for germination of Hycrest on all plots, but seedlings were unable to compete with either high or low densities of cheatgrass. Hycrest seedlings emerging from cattle dung were more successful in establishing on squirreltail plots, and most successful in establishing on the control plots (bare ground). Cheatgrass plants located near cattle and sheep dung benefited from an input of nutrients and a gapformation (with cattle dung), which translated into greater plant height, weight, and fecundity. The squirreltail plants did not show any noticable advantages gained from adjacent dung deposition. Even though cheatgrass was suppressed by cattle dung on the surface, its roots proliferated in the soil profile immediately under the cattle dungpat to levels equal to that found in other areas within the plots.

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