Filters: Tags: Castor canadensis (X) > Types: Citation (X)
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Beavers (Castor canadensis Kuhl) can influence the competitive dynamics of plant species through selective foraging, collection of materials for dam creation, and alteration of hydrologic conditions. In the Grand Canyon National Park, the native Salix gooddingii C.R.Ball (Goodding?s willow) and Salix exigua Nutt. (coyote willow) are a staple food of beavers. Because Salix competes with the invasive Tamarix ramosissima Ledeb., land mangers are concerned that beavers may cause an increase in Tamarix through selective foraging of Salix. A spatial analysis was conducted to assess whether the presence of beavers correlates with the relative abundance of Salix and Tamarix. These methods were designed to detect a system-wide...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Castor canadensis,
Colorado River,
Salix,
Springer Netherlands,
Wetlands,
We compared beaver (Castor canadensis) foraging patterns on Fremont cottonwood (Populus deltoides subsp. wislizenii) saplings and the probability of saplings being cut on a 10 km reach of the flow-regulated Green River and a 8.6 km reach of the free-flowing Yampa River in northwestern Colorado. We measured the abundance and density of cottonwood on each reach and followed the fates of individually marked saplings in three patches of cottonwood on the Yampa River and two patches on the Green River. Two natural floods on the Yampa River and one controlled flood on the Green River between May 1998 and November 1999 allowed us to assess the effect of flooding on beaver herbivory. Independent of beaver herbivory, flow...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Castor canadensis,
Flaming Gorge Dam,
Green River,
Populus deltoides,
River Research and Applications,
Populations of beaver and willow have not thrived in riparian environments that are heavily browsed by livestock or ungulates, such as elk. The interaction of beaver and elk herbivory may be an important mechanism underlying beaver and willow declines in this competitive environment. We conducted a field experiment that compared the standing crop of willow three years after simulated beaver cutting on paired plants with and without intense elk browsing (85% utilization rate). Simulated beaver cutting with intense elk browsing produced willow that was small (biomass and diameter) and short, with far fewer, but longer, shoots and a higher percentage of dead biomass. In contrast, simulated beaver cutting without elk...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Castor canadensis,
Ecological Applications,
Rocky Mountain National Park,
Salix monticola,
beaver,
Beaver herbivory of willow under two flow regimes: a comparative study on the Green and Yampa rivers
The effect of flow regulation on plant-herbivore ecology has received very little attention, despite the fact that flow regulation can alter both plant and animal abundance and environmental factors that mediate interactions between them. To determine how regulated flows have impacted beaver (Castor Canadensis) and sandbar willow (Salix exigua) ecology, we first quantified the abundance and mapped the spatial distribution of sandbar willow on alluvial sections of the flow-regulated Green River and free-flowing Yampa River in northwestern Colorado. We then established 16 and 15 plots (1 m x 2.7 m) in patches of willow on the Green and Yampa Rivers, respectively, to determine whether rates of beaver herbivory of willow...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Castor canadensis,
Salix exigua,
Western North American Naturalist,
foraging behavior,
herbivory,
Beaver (Castor canadensis) populations have declined or failed to recover in heavily browsed enviÂronments. I suggest that intense browsing by livestock or ungulates can disrupt beaver-willow (Salix spp.) mutuÂalisms that likely evolved under relatively low herbivory in a more predator-rich environment, and that this inter action may explain beaver and willow declines. Field experiments in Rocky Mountain National Park, Colorado, USA, found the interaction of beaver and elk (Cervus elaphus) herbivory suppressed compensatory growth in wilÂlow. Intense elk browsing of simulated beaver-cut willow produced plants which were small and hedged with a high percentage of dead stems, whereas protected plants were large...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Castor canadensis,
Cervus elaphus,
Lutra,
Mutualism,
Salix,
Beaver–willow (Castor-Salix) communities are a unique and vital component of healthy wetlands throughout the Holarctic region. Beaver selectively forage willow to provide fresh food, stored winter food, and construction material. The effects of this complex foraging behavior on the structure and function of willow communities is poorly understood. Simulation modeling may help ecologists understand these complex interactions. In this study, a modified version of the SAVANNA ecosystem model was developed to better understand how beaver foraging affects the structure and function of a willow community in a simulated riparian ecosystem in Rocky Mountain National Park, Colorado (RMNP). The model represents willow in...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Castor canadensis,
Ecological Modelling,
Rocky Mountain National Park,
Salix,
beaver,
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