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Diamond J.M.,Wildlife Contracts Branch | Call C.A.,Utah State University | Devoe N.,Natural Resource Specialist
Invasive Plant Science and Management | Year: 2012

Downy brome (Bromus tectorum L.)-dominated communities can remain as stable states for long periods, even with frequent disturbance by grazing and fire. The objective of this study was to determine the effectiveness of using targeted cattle grazing and late-season prescribed burning, alone and in combination, to reduce B. tectorum seed bank input and seed bank density and thus alter aboveground community dynamics (species composition) on a B. tectorum-dominated landscape in northern Nevada. Cattle removed 80 to 90% of standing biomass in grazed plots in May of 2005 and 2006 when B. tectorum was in the boot (phenological) stage. Grazed and ungrazed plots were burned in October 2005 and 2006. The combined grazing-burning treatment was more effective than either treatment alone in reducing B. tectorum seed input and seed bank density, and in shifting species composition from a community dominated by B. tectorum to one composed of a suite of species, with B. tectorum as a component rather than a dominant. This study provides a meso-scale precursor for landscape-scale adaptive management using grazing and burning methodologies. © 2012 Weed Science Society of America. Source

Diamond G.F.,WestLand Resources Inc | Diamond J.M.,Wildlife Contracts Branch
Western North American Naturalist | Year: 2014

With the loss and modification of natural roosting habitat afforded by caves, abandoned mines have assumed increased importance as alternative roosting sites for Townsend's big-eared bats (Corynorhinus townsendii). However, increased human safety concerns have led to accelerated abandoned mine closure programs. To protect roosting sites in mines with significant bat activity, bat-compatible gates are installed that allow continued access to mine workings. Aside from ensuring public safety, these gates provide protection from disturbance to roosting bats. We evaluated the effects of gating on bat flight behavior at maternity colonies in 2 previously gated (control) and 2 ungated (treatment) mines that were gated during this study. We used an infrared video camera to record bat flight behavior at the entrances to each of the 4 study mines for 2 consecutive mornings and a single night each month during the warm season. Entrance (03:00-06:00) and emergence (21:00-24:00) surveys comprised 3 consecutive hours. Overall circling activity increased more than 6-fold at openings of treatment mines following gating (P < 0.001). Crowding during emergence was significantly higher (P = 0.023) in newly gated mines than in previously gated mines. Gates affect subadults during the initial-volancy periods, as detected through collisions with the gates. Increased activity of bats and collisions with the gate, which result in bats falling to the ground at mine openings, may amplify vulnerability to predators and increase energetic demands. © 2014. Source

Gagnon J.W.,Wildlife Contracts Branch | Loberger C.D.,Wildlife Contracts Branch | Sprague S.C.,Wildlife Contracts Branch | Ogren K.S.,Wildlife Contracts Branch | And 2 more authors.
Human-Wildlife Interactions | Year: 2015

Collisions with large ungulates cause serious human and animal injuries and significant property damage. Therefore, wildlife crossing structures are increasingly included in new road construction to reduce wildlife-vehicle collisions, while still allowing wildlife to safely cross roads. Recently, state and federal transportation budgets have declined, concomitantly reducing the construction of wildlife crossing structures, which are generally tied to large-scale reconstruction projects that are delayed for decades into the future. Nevertheless, even during times of fiscal constraint or temporal delay, it is still necessary to reduce collisions with wildlife and maintain habitat connectivity. Therefore, it is important to find cost-effective and functional alternatives. Retrofitting roadways with wildlife exclusion fencing that directs animals to existing highway structures (e.g., sufficiently sized bridges and culverts) is a possible costeffective, interim solution that needs further testing. Along Interstate-17 in northern Arizona, we heightened 9.17 km of right-of-way barbed wire fence to 2.4 m to guide elk (Cervus canadensis) to 2 large bridges and 2 modified transportation interchanges. We evaluated occurrence of elk-vehicle collisions, elk use of existing structures, and GPS movements of elk pre-and post-fencing retrofit. Post retrofit, there was a 97% reduction in elk-vehicle collisions for the 9.17 km stretch of road. There were also no increases in collisions at the fence termini (area within 1.61 km from fence ends) nor in the remaining sections, indicating that elk were not simply forced to those areas. We documented a 217% and 54% increase in elk use of the 2 large bridges, but no elk use of the transportation interchanges. GPS relocation data from 31 elk showed a statistically insignificant decrease, from 0.07 to 0.03 crossings per approach pre-and post-fence modification, respectively. Elk road crossings, determined through GPS relocations, were concentrated around the bridge structures rather than being evenly distributed across the treatment sections, and similar to collisions, crossings did not increase on adjacent fence termini. Using the Huijser et a. (2009) estimate of $17,483 for the cost to society of an elk-vehicle collision, the level of collision reduction on this stretch of road will recoup project costs in <5 years. Our results indicate that, under certain circumstances, retrofits can in the short-term reduce wildlife-vehicle collisions on roadways that are not scheduled to be reconstructed in the near future. However, for the long-term, areas with significant wildlife-vehicle collisions or habitat fragmentation should have appropriately designed, located, and maintained wildlife crossings with exclusionary funnel fencing. Source

Diamond J.M.,Wildlife Contracts Branch | Gwinn R.N.,Wildlife Contracts Branch | Johnson J.,U.S. Army | Telle H.,U.S. Army | Diamond G.F.,WestLand Resources Inc
Western North American Naturalist | Year: 2015

Big brown bats (Eptesicus fuscus) and a close relative of Arizona myotis (Myotis occultus), the little brown bat (Myotis lucifugus) in the eastern United States, are among those species experiencing unprecedented population declines related to white-nose syndrome (WNS). Determining population characteristic baselines for big brown bat and Arizona myotis is paramount in detecting population declines before they reach critical levels. We targeted 2 bat species strongly associated with ponderosa pine forests in northern Arizona. Big brown bats and Arizona myotis readily utilize human-made structures and have a cosmopolitan distribution across the ponderosa pine (Pinus ponderosa) ecosystem of northern Arizona (Adams 2003). Between 2005 and 2012 we installed artificial bat roosts at Camp Navajo near Flagstaff, Arizona. We captured bats at these roosting structures and marked them using modified bird bands. We established baseline population characteristics on Camp Navajo by utilizing a 7-year mark-and-recapture data set. We also provide a measure of population status that may be compared across temporal scales within the study area. In essence, this study provides the basis for an early warning system for WNS in Arizona. © 2015 Western North American Naturalist. Source

Grandmaison D.D.,Wildlife Contracts Branch | Frary V.J.,Wildlife Contracts Branch
Journal of Wildlife Management | Year: 2012

The expansion of road networks in desert tortoise (Gopherus agassizii) habitat in the Sonoran Desert has raised questions concerning appropriate mitigation to reduce impacts at the population level. Although some effects, namely road-kill and habitat loss, have been well documented, illegal tortoise collection has been insufficiently addressed. It has become increasingly important for wildlife and land-use managers to understand the cumulative impacts of roads on tortoises and the effect that those impacts have on population persistence. We estimated the probability of desert tortoise detection and collection along 2-lane paved, maintained gravel, and non-maintained gravel roads to evaluate whether collection probabilities were related to road type. Although collection probability did not vary by road type, the probability of desert tortoise detection by passing motorists was greatest on maintained gravel roads and fewest on non-maintained gravel and paved roads. These results have implications for effectively mitigating the impacts of roads on desert tortoises. Published 2011. This article is a U.S. Government work and is in the public domain in the USA. © 2011 The Wildlife Society. Source

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