Showing papers by "Roger A. Baldwin published in 2012"
TL;DR: In this article, the authors used information from capture and remote-triggered cameras, as well as visitor information, to derive a minimum known population estimate of 20−24 individuals and a median density estimate of 1.35 bears/100 km2.
Abstract: Rocky Mountain National Park (RMNP) is home to a low-density black bear (Ursus americanus) population that exists at >2,400 m with a very limited growing season. A previous study (1984–1991) found bear densities among the lowest reported (1.37–1.52 bears/100 km2). Because of concerns of viability of this small population, we assessed population size and density of black bears from 2003 to 2006 to determine the current status of RMNP’s bear population. We used three approaches to estimate population size and density: (1) minimum number known, (2) occupancy modeling, and (3) catch per unit effort (CPUE). We used information from capture and remote-triggered cameras, as well as visitor information, to derive a minimum known population estimate of 20–24 individuals and a median density estimate of 1.35 bears/100 km2. Bear occupancy was estimated at 0.46 (SE = 0.11), with occupancy positively influenced by lodgepole pine stands, non-vegetated areas, and patch density but negatively influenced by mixed conifer stands. We combined the occupancy estimate with mean home-range size and overlap for bears in RMNP to derive a density estimate of 1.44 bears/100 km2. We also related CPUE to density estimates for eight low-density black bear populations to estimate density in RMNP; this estimate (1.03 bears/100 km2) was comparable to the occupancy estimate and suggests that this approach may be useful for future population monitoring. The use of corroborative techniques for assessing population size of a low-density black bear population was effective and should be considered for similar low-density wildlife populations.
8 citations
TL;DR: The authors studied habitat relationships of elk at scales of landscape, home range, and site on and adjacent to Chaco Culture National Historical Park, San Juan and McKinley counties, New Mexico.
Abstract: We studied habitat relationships of elk (Cervus elaphus) at scales of landscape, home range, and site on and adjacent to Chaco Culture National Historical Park, San Juan and McKinley counties, New Mexico. Across scales, use of habitats was driven by needs for cover. Pinyon–juniper and rocky habitats were used most often. Accrual of body fat was related most strongly to lactation and precipitation but also was influenced by several habitats, most strongly by semi-desert shrub-steppe. Habitats positively related to accrual of body fat were used less than available at scales of landscape and home range. Conversely, habitats preferentially included and used in home ranges were related negatively to accrual of body fat, further highlighting the importance of cover. At the level of site, feeding sites had greater cover by shrubs (≥23% versus 25% versus <11%) than did bedding sites, whereas bedding sites had higher overstory cover (≥46% versus ≤4%). Bedding sites most frequently ...
7 citations
01 Jan 2012
TL;DR: Baldwin et al. as discussed by the authors tested aluminum phosphide and gas cartridge burrow fumigation in an alfalfa field in Butte Valley, CA, to determine if either of these approaches were efficacious and cost effective for controlling Belding's ground squirrels.
Abstract: Author(s): Baldwin, Roger A.; Quinn, Niamh | Abstract: Rodenticides are often used to control burrowing rodents but have not been overly efficacious for Belding’s ground squirrels due to poor bait acceptance. This has left alfalfa growers searching for alternative options for controlling this rodent species. As such, we tested aluminum phosphide and gas cartridge burrow fumigation in an alfalfa field in Butte Valley, CA, to determine if either of these approaches were efficacious and cost effective for controlling Belding’s ground squirrels. A comparison of the number of burrows treated and the number of burrows reopened 48-hours post-treatment indicated that both burrow fumigants were highly effective (aluminum phosphide = 94-98%, gas cartridges = 100%). The average cost per application was $1.05 and $2.92 for aluminum phosphide and gas cartridges, respectively. Given the almost 3-fold difference in cost of application between the two approaches, aluminum phosphide appears to be the more practical approach for Belding’s ground squirrel control. Although we currently lack an approach for estimating the amount of damage that Belding’s ground squirrels are likely to cause to an alfalfa field, it seems plausible that burrow fumigation could be a cost effective approach to reduce damage caused by this species, particularly if long-term control can be obtained. Possible long-term management options for Belding’s ground squirrels are discussed.
7 citations
01 Jan 2012
TL;DR: Baldwin et al. as mentioned in this paper found that 49,005 lbs of active ingredient (AI) of ALP was used for burrowing mammal control in 2010 with most applications occurring in residential areas, applied primarily by licensed Pest Control Operators who specialize in vertebrate IPM.
Abstract: Author(s): Baldwin, Roger A. | Abstract: Aluminum phosphide (ALP) is used extensively for burrowing mammal control. However, recent changes have been made to the ALP label which could substantially limit its utility for burrowing mammal control in the future. As such, I developed surveys to help quantify the impact that these changes are likely to have on ALP usage and vertebrate Integrated Pest Management in California. These survey findings were compared to information gathered from the California Department of Pesticide Regulation’s Pesticide Use Report for 2010 to relate the survey findings to the broader spectrum of users throughout California. I found that 49,005 lbs of active ingredient (AI) of ALP was used for burrowing mammal control in 2010, with most applications occurring in residential areas, applied primarily by licensed Pest Control Operators who specialize in vertebrate IPM. Most applications were applied to control pocket gophers, while ground squirrel and mole burrow systems were also treated. Collectively, new buffer and posting restrictions resulted in expected losses of 70% and 26% of agricultural applications of ALP for pocket gophers and ground squirrels, respectively. The impact of restrictions in residential areas may be even more extreme, with estimated reductions in ALP applications ranging from 70-98%. Alternative control methods were typically considered less efficacious than ALP. Furthermore, 13-34% of respondents indicated that they would no longer control these pests in areas where they could not use ALP. Insufficient or ineffective management programs targeted at these pests could result in increased economic damage, greater human health and safety concerns, and increased environmental degradation. Even though ALP has a safe track record in California, ALP users were willing to obtain greater training on its safe use while adhering to a 67% increase in the previous 15-foot buffer restriction, if it meant relaxing some of the current restrictions. Because of the extreme importance of burrowing mammal control, combined with the high efficacy and safe track record of ALP, perhaps these or alternative mitigation steps should be considered to ensure the safe and effective use of ALP. Otherwise, it is quite possible that the estimated 85% reduction in future ALP applications for burrowing mammal control could result in far greater negative consequences than the benefits gained from the new regulations.
5 citations
01 Jan 2012
TL;DR: Hornbaker et al. as discussed by the authors proposed the Rodenticide Cluster Reregistration Eligibility Decision (RED) in 1998 in response to human health and environmental concerns associated with rodenticides.
Abstract: Author(s): Hornbaker, Victoria L.; Baldwin, Roger A.; Richards, Sara N. | Abstract: The United States Environmental Protection Agency (EPA) issued the Rodenticide Cluster Reregistration Eligibility Decision (RED) in July 1998 in response to human health and environmental concerns associated with rodenticides. The EPA and its stakeholders worked for 10 years developing risk assessments and mitigation plans, issuing the final Risk Mitigation Decision (RMD) on May 28, 2008. The RMD restricts retail sale of second-generation anticoagulant rodenticides for commensal use and it refers field use rodenticide registrants back to the RED, which makes those products Restricted Use. This means that all applications of field use products must be made by a certified applicator. These changes have potentially large ramifications for smaller private applicators that are generally not certified to use Restricted Use materials. The California Department of Food and Agriculture, the University of California Cooperative Extension, and the California Department of Pesticide Regulation worked collaboratively to streamline the exam process for private applicators, allowing for a time-limited exam through June 2012. The concern for the Vertebrate Pest Control Research Advisory Committee (VPCRAC) is that many people will not take and/or pass the exam. This will impact the ability to effectively control rodent pests in some areas and may affect the revenue stream supporting the VPCRAC program. Preliminary sales data is not indicative of any impact to the program, but it may be too early to accurately draw any conclusions.
1 citations