Crested wheatgrass establishment in livestock dung deposited on degraded rangeland vegetation types in the intermountain west, USA

Abstract

Cattle and sheep were examined as seed disseminators for revegetating degraded rangelands in the Intermountain region of the western United States. “Hycrest” crested wheatgrass [Agropyron desertorum (Fisch, ex Link) Schult, x A. cristatum (L.) Gaert.] seed was fed to Holstein steers and Suffolk ewes. Dung 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 (Elymus elymoides (Raf.) Swezey)] grass species. The experiment evaluated the suppression of resident vegetation by dung, and the establishment of crested wheatgrass in dung. Sheep dung did not suppress resident vegetation nor did it provide crested wheat‐grass with a favorable microsite for germination and establishment. Cattle dung provided favorable conditions for germination of crested wheatgrass, but seedlings were unable to compete with either high or low densities of cheatgrass. Even though aboveground growth of cheatgrass was suppressed by cattle dung, its roots proliferated in the soil profile immediately under cattle dung pats to levels equal to that found in other areas within the plots. Crested wheatgrass seedlings emerging from cattle dung were more successful in establishing on squirreltail plots, and most successful in establishing on the bare ground control plots. Cheatgrass plants located near cattle and sheep dung benefited from an input of nutrients and the creation of gaps (with cattle dung), which translated into greater plant height, weight, and fecundity. Squirreltail plants did not show any noticeable growth responses to adjacent dung.