Elk, Mule Deer, and Cattle Foraging Relationships on Foothill and Mountain Rangeland

Abstract

Foraging niche overlap among Rocky Mountain elk (Cervus elaphus nelsoni), Rocky Mountain mule deer (Odocoileus hemionus hemionus), and cattle (Bos taurus) was studied for 2 years on 37 000 ha of nonforested foothill and mountain habitat in northwestern Wyoming. Microhistological analysis was used to quantify botanical composition of ungulate diets from monthly fecal collections. Feeding habitat use was determined through monthly surveys from fixed-wing aircraft to record nonsolitary animals in nonforested habitat. Kulcyznski's similarity index was used to calculate dietary and feeding habitat overlap among the 3 ungulates, and these 2 indices were multiplied together to estimate foraging niche overlap. In all seasons, elk and cattle consumed grass-dominated diets (mean ¼ 61% and 81%, respectively), although elk diets were more diverse. Mule deer consumed more forbs and shrubs than either elk or cattle (P , 0.10). Foraging niche overlap was high (45%) between mule deer and elk in spring. Cattle in summer and fall had !60% foraging niche overlap with elk in spring, indicating that, in spring, elk foraged in many of the same places (largely sagebrush grassland) and ate diets similar in botanical composition to what cattle did during summer and fall (principally Festuca idahoensis, Pseudoroegneria spicata, and Achnatherum spp.). Foraging niche overlap also was high (41%-51%) between elk in winter and cattle in summer and fall. Therefore, if competitive or complementary relationships existed between elk and cattle, these interactions most likely occurred on sagebrush grasslands where cattle use in summer-fall was followed by elk use in winter-spring. We recommend that resource managers focus their forage utilization and range trend monitoring in foothill sagebrush grasslands. ResumenSe estudió el traslape del nicho de forrajeo entre el alce de las Montañ as Rocallosas, (Cervus elaphus nelsoni), el venado mula de las Montañ as Rocallosas (Odocoileus hemionus hemionus) y el ganado (Bos taurus); el estudio se condujo por dos añ os en 37 000 ha de hábitats deforestado al pie de montañ a y montañ oso situados en el noroeste de Wyoming. La composició n botá nica de la dieta de los ungulados se determinó a partir de muestras fecales colectadas mensualmente y con el uso del análisis microhistoló gico. El uso de há bitat alimenticio se determinó a través de muestreos mensuales por medio de un dispositivo aéreo de alas fijas para registrar los animales no solitarios en el há bitat deforestado. El índice de similaridad de Kulcyznski se uso para calcular el traslape de la dieta y del há bitat alimenticio entre los tres ungulados, y estos dos índices se multiplicaron para estimar el traslape del nicho de forrajeo. En todas las épocas de añ o, el alce y el ganado consumieron dietas dominadas por zacates (media ¼ 61% y 81%, respectivamente), aunque las dietas del alce fueron má s diversas. El venado mula consumió más hierbas y arbustos que el alce y el ganado (P , 0.10). En primavera, el traslape del nicho de forrajeo fue a...

Winter Resource Selection by Mule Deer on the Wyoming–Colorado Border Prior to Wind Energy Development

“…As mentioned previously, shrublands are important thermal environments, but also serve as foraging sites and in reducing risk (i.e., security cover). It is well known that shrubs are important to mule deer during winter (e.g., Carpenter et al 1979;Pierce et al 2004), composing the greatest percentage of the diet on a seasonal and annual basis (Kasworm et al 1984;Kucera 1997;Nicholson et al 2006;Torstenson et al 2006). Shrublands also provide security cover from predation or disturbance from anthropogenic activities.…”

Ecological, Economic, and New Synthetic Perspectives in Range Management: An Interpretative Essay

“…The obvious management implication is that in desert rangelands of the sort studied in this paper, mixed species grazing involving prairie dogs and sheep is unlikely to be efficient but mixed species grazing involving goats and prairie dogs is a lot more likely to be efficient and hence successful. 10 The desirability of mixed species grazing over time such that different animal species graze the same rangeland at different points in time has been analyzed by Ralphs (2005) and by Torstenson et al (2006). Given that sheep are more resistant to larkspur poisoning than cattle, Ralphs (2005) studies whether it is possible to use sheep as an effective management tool by conditioning them to graze larkspur early in its growth stages and thereby diminish the likelihood of cattle poisoning.…”

“…This paper shows that although it is possible to positively condition sheep to graze larkspur, the extent and the timing of this consumption is ''not sufficient to prevent potential cattle poisoning'' (Ralph, 2005, p. 628). Torstenson et al (2006) focus on the dietary habits of cattle and Rocky mountain elk in a nonforested foothill and mountain rangeland in northwestern Wyoming. On a more positive note, these researchers point out that on sagebrush grasslands, mixed species grazing involving forage consumption by cattle in summer-fall followed by forage consumption by elk in winter-spring is likely to be successful.…”

Forb Nutrient Density for Sage Grouse Broods in Mountain Big Sagebrush Communities, Montana

“…Elk, like domestic sheep and cattle, will compete directly with sage grouse because they utilize forbs readily in the spring until grasses become available. 12 Although competition among wild and domestic species can occur, there may be periods when the level of interaction declines because feeding preferences shift to other seasonally available forages.…”