Wolverines (Gulo gulo) are one of the rarest carnivores in the contiguous United States. Effective population sizes in Montana, Idaho, and Wyoming, where most of the wolverines in the contiguous United States exist, were calculated to be 35 (credible limits, 28 52) suggesting low abundance. Landscape features that influence wolverine population substructure and gene flow are largely unknown. Recent work has identified strong associations between areas with persistent spring snow and wolverine presence and range. We tested whether a dispersal model in which wolverines prefer to disperse through areas characterized by persistent spring snow cover produced least-cost paths among all individuals that correlated with genetic distance among individuals. Models simulating large preferences for dispersing within areas characterized by persistent spring snow explained the data better than a model based on Euclidean distance. Partial Mantel tests separating Euclidean distance from spring snow-cover-based effects indicated that Euclidean distance was not significant in describing patterns of genetic distance. Because these models indicated that successful dispersal paths followed areas characterized by spring snow cover, we used these understandings to derive empirically based least-cost corridor maps in the U.S. Rocky Mountains. These corridor maps largely explain previously published population subdivision patterns based on mitochondrial DNA and indicate that natural colonization of the southern Rocky Mountains by wolverines will be difficult but not impossible.
Though recent research has shown that written corrective feedback (WCF) may improve aspects of writing accuracy in some English as a second language (ESL) contexts, many teachers continue to be confused about the practical steps they should utilize to help their students improve their writing. Moreover, some have raised concerns as to whether commonly used approaches to ESL writing pedagogy and grammar instruction are effective in helping students improve their linguistic accuracy. This article describes an instructional strategy we developed for improving students' accuracy based on insights gleaned from practice, research, and theory. We refer to this instructional methodology as dynamic WCF. The article also discusses a test of the methodology's efficacy that compared the performance of two groups of students, one using a conventional process approach to writing instruction and the other using the dynamic WCF approach. Test results demonstrated that although rhetorical competence, writing fluency, and writing complexity were largely unaffected by the dynamic WCF pedagogy, significant improvement was observed for writing accuracy.
In North America, wolverines once occupied a continuous range from Alaska southward to New Mexico. In the lower 48 states, small remnant populations remain only in the northwestern United States. Among these remnant populations, the Montana population has the highest probability of long-term persistence given its size and proximity to healthy populations in Canada. In this study, we evaluate population genetic structure and gene flow among Montana wolverines using 10 polymorphic microsatellite loci. Bayesian and frequency-based assignment tests revealed significant population substructure and provide support for at least three subpopulations in Montana. FST values between subpopulations ranged from 0.08 to 0.10 and provide evidence for male-biased dispersal. The high degree of population substructure and low levels of gene flow contrast results from wolverine population genetic studies in less fragmented landscapes of Alaska and Canada. This study provides additional support for the hypothesis that large carnivore populations of Montana are becoming increasingly fragmented due to human development and disturbance.
Recent research in reading comprehension has focused on the processes of reading, while recent thinking in language testing has recognized the impor tance of gathering information on test taking processes as part of construct validation. And while there is a growing body of research on test-taking strate gies in language testing, as well as research into the relationship between item content and item performance, no research to date has attempted to examine the relationships among all three - test taking strategies, item content and item performance. This study thus serves as a methodological exploration in the use of information from both think-aloud protocols and more commonly used types of information on test content and test performance in the investigation of construct validity.
Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (∼3 to 8 km per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations.
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