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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...
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This ArcGIS shapefile shows the known locations of beaver dams in the Tualatin Basin. The dam location information was generated by multiple local agencies, groups, and organizations. The local sources had identified the beaver dams between 2011 and 2019. USGS worked with these local sources to combine all data into one inventory.
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...
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This ArcGIS shapefile shows the known locations of beaver activity (including beaver chews, lodges, and dams) in the Tualatin Basin. USGS was intending to collect information about the locations of beaver dams. Often, the GPS coordinates of dams were not known, but the beaver-affected areas were known. The information about locations with beaver activity was generated by multiple local agencies, groups, and organizations. The local sources had identified the beaver activity locations between 2013 and 2016. USGS worked with these local sources to combine all data into one inventory.
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USGS met with 13 local groups and organizations around the Portland, Oregon region to collect information regarding the locations of beaver dams in the Tualatin Basin. The local sources had identified beaver dams between 2011 and 2019, and data were compiled by USGS into an ArcGIS shapefile. Often, the local groups did not know the GPS coordinates of beaver dams, but they had identified beaver-affected reaches during that same time period. Therefore, a second shapefile was created to include the locations of beaver activity (including beaver chews, lodges, and dams) in the Tualatin Basin. The Beaver Dam Locations ArcGIS shapefile shows the known locations of beaver dams in the Tualatin Basin. The Beaver Activity...
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...
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...
Beaver (Castor canadensis) populations have declined or failed to recover in heavily browsed envi­ronments. I suggest that intense browsing by livestock or ungulates can disrupt beaver-willow (Salix spp.) mutu­alisms 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 wil­low. 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...
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Some of the SNK rasters intentionally do not align or have the same extent. These rasters were not snapped to a common raster per the authors' discretion. Please review selected rasters prior to use. These varying alignments are a result of the use of differing source data sets and all products derived from them. We recommend that users snap or align rasters as best suits their own projects. - This dataset consists of raster distribution maps for terrestrial vertebrate species in Alaska. Individual species distribution maps were developed using the best available known occurrence points for each species and modeled using MaxEnt software and a series of environmental predictor variables. Output maps were clipped...
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...
    map background search result map search result map Beaver dam locations and beaver activity in the Tualatin Basin, Oregon (ver. 2.0, November 2019) Beaver dam locations in the Tualatin Basin, Oregon, between 2011 and 2019 Beaver activity locations in the Tualatin Basin, Oregon, between 2013 and 2016 BLM REA SNK 2010 Alaska Gap Analysis Project: Year Round Distribution Map for Castor canadensis Beaver activity locations in the Tualatin Basin, Oregon, between 2013 and 2016 Beaver dam locations and beaver activity in the Tualatin Basin, Oregon (ver. 2.0, November 2019) Beaver dam locations in the Tualatin Basin, Oregon, between 2011 and 2019 BLM REA SNK 2010 Alaska Gap Analysis Project: Year Round Distribution Map for Castor canadensis