Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Reading Level
      Reading Level
      Clear All
      Reading Level
  • Content Type
      Content Type
      Clear All
      Content Type
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
      More Filters
      Clear All
      More Filters
      Item Type
    • Is Full-Text Available
    • Subject
    • Publisher
    • Source
    • Donor
    • Language
    • Place of Publication
    • Contributors
    • Location
1,023 result(s) for "Thompson, Sarah J."
Sort by:
New directions in medieval manuscript studies and reading practices : essays in honor of Derek Pearsall
\"This volume gathers the contributions of senior and junior scholars-all indebted to the pathbreaking work of Derek Pearsall-to showcase new research prompted by his rich and ongoing legacy as a literary critic, editor, and seminal founder of Middle English manuscript studies. The contributors aim both to honor Pearsall's work in the field he established and to introduce the complexities of interdisciplinary manuscript studies to students already familiar with medieval literature. The contributors explore a range of issues, from the study of medieval literary manuscripts to the history of medieval books, libraries, literacy, censorship, and the social classes who used the books and manuscripts-nobles, children, schoolmasters, priests, merchants, and more. In addressing reading practices, essays provide a wealth of information on marginal commentaries, images and interpretive methods, international transmission, and early print and editorial methods. \"New Directions in Medieval Manuscript Studies and Reading Practices marks the heritage of the distinguished scholar Derek Pearsall while highlighting his continuing influence on medieval manuscript studies. Buoyed by fine work of senior scholars, the collection also introduces readers to stimulating work by an upcoming generation of more recent practitioners, all of whom address crucial issues in the field: the particulars of individual manuscripts, including scribal practice, marginal commentary, and audience reception. The result is a fine collection at once canonical in some respects and innovative in others.\" -Paul H. Strohm, Anna S. Garbedian Professor Emeritus of the Humanities, Columbia University\"-- Provided by publisher.
When Winners Become Losers: Predicted Nonlinear Responses of Arctic Birds to Increasing Woody Vegetation
Climate change is facilitating rapid changes in the composition and distribution of vegetation at northern latitudes, raising questions about the responses of wildlife that rely on arctic ecosystems. One widely observed change occurring in arctic tundra ecosystems is an increasing dominance of deciduous shrub vegetation. Our goals were to examine the tolerance of arctic-nesting bird species to existing gradients of vegetation along the boreal forest-tundra ecotone, to predict the abundance of species across different heights and densities of shrubs, and to identify species that will be most or least responsive to ongoing expansion of shrubs in tundra ecosystems. We conducted 1,208 point counts on 12 study blocks from 2012-2014 in northwestern Alaska, using repeated surveys to account for imperfect detection of birds. We considered the importance of shrub height, density of low and tall shrubs (i.e. shrubs >0.5 m tall), percent of ground cover attributed to shrubs (including dwarf shrubs <0.5 m tall), and percent of herbaceous plant cover in predicting bird abundance. Among 17 species considered, only gray-cheeked thrush (Catharus minimus) abundance was associated with the highest values of all shrub metrics in its top predictive model. All other species either declined in abundance in response to one or more shrub metrics or reached a threshold where further increases in shrubs did not contribute to greater abundance. In many instances the relationship between avian abundance and shrubs was nonlinear, with predicted abundance peaking at moderate values of the covariate, then declining at high values. In particular, a large number of species were responsive to increasing values of average shrub height with six species having highest abundance at near-zero values of shrub height and abundance of four other species decreasing once heights reached moderate values (≤ 33 cm). Our findings suggest that increases in shrub cover and density will negatively affect abundance of only a few bird species and may potentially be beneficial for many others. As shrub height increases further, however, a considerable number of tundra bird species will likely find habitat increasingly unsuitable.
Estimating survival of unmarked neonates with camera traps
Survival and recruitment of offspring are important drivers of population dynamics. Yet, studying wildlife shortly after parturition is logistically challenging and oftentimes cost‐prohibitive. As a result, our ecological understanding of neonate survival is limited for many species and management decisions are often made without an adequate understanding of their implications. We developed a model to estimate the overall survival rate of neonates and the timing of mortality (i.e., shape of the survival curve) based on changes in the ratio of neonates to adult females observed in camera trap photographs. We evaluated the model with simulations and provided an example application using North American elk (Cervus canadensis) in Idaho. Our simulations suggested that estimates of the overall neonate survival rate and the shape of the survival curve are accurate when researchers provide unbiased estimates of adult female survival, birth rate (offspring per adult female), and the distribution of birth dates. When researchers can provide a priori values for just adult female survival and birth rate, estimates of the overall survival rate were accurate, but early neonate mortality was underestimated. Our estimate of neonate elk survival in Idaho was consistent with values generated by capture‐based studies. Our ratio‐based model provides an alternative to traditional methods for estimating neonate survival and does not rely on invasive or expensive capture and monitoring techniques. We believe this method could apply to a wide variety of species due to the ease of data collection and the relatively small number of critical model assumptions. A major benefit of our model is the ability to simultaneously monitor other species in the community, which will facilitate a better understanding of drivers of variation in neonate survival.
Grassland birds demonstrate delayed response to large‐scale tree removal in central North America
Maintenance of early successional and open habitats often requires active removal of encroaching vegetation. In many cases, fire or other historically applied methods can no longer maintain or create open or early‐successional habitat. In these situations, managers must employ mechanical or chemical treatments to control vegetation and improve habitat quality for wildlife that depend on open habitats. We conducted a large‐scale study of tree removal from 2005 to 2011 on 14 grassland sites in central North America. Beginning in the autumn of 2005, shrubs, scattered trees, shelterbelts and woodlots were removed from six of fourteen study sites with cutting and burning treatments. Trees and shrubs accounted for 7–21% of pre‐treatment ground cover. We conducted vegetation and bird surveys on each site for one year before and six years after initiating tree removal treatments. Treatments effectively removed larger woody vegetation (>6 m in height), but effects of shrub removal were less consistent due to rapid regrowth. Tree removal sites also experienced reductions in grassy litter as a result of prescribed fires that were used to discourage shrub and tree regrowth. On untreated sites, abundance of all grassland birds declined throughout the study, on average declining by 62%. On tree removal sites, we estimated that grassland bird abundance dropped from 2·04 (birds per count) before treatment to a low of 0·90 in the second year after initiating treatments, but recovered in the final three years of study with a weak, but significant positive response six years after initiating treatment, with an estimated 1·42 birds per count. Waterfowl and wetland birds increased following tree removal, whereas woodland birds, particularly those that nest in cavities, declined on treated sites. Synthesis and applications. Tree removal did appear to improve habitat suitability for grassland birds, but a positive response was weak and delayed, and treatments caused short‐term habitat disturbances that significantly reduced abundance of target species. When planning large‐scale tree removal, it may be beneficial to allow undisturbed habitat in the surrounding landscape to ameliorate potential short‐term displacement of wildlife in early phases of treatment. In addition, managers should expect site recovery to require repeated treatments over multiple years.
Autonomous Acoustic Recorders Reveal Complex Patterns in Avian Detection Probability
Avian point-count surveys are typically designed to occur during periods when birds are consistently active and singing, but seasonal and diurnal patterns of detection probability are often not well understood and may vary regionally or between years. We deployed autonomous acoustic recorders to assess how avian availability for detection (i.e., the probability that a bird signals its presence during a recording) varied during the breeding season with time of day, date, and weather-related variables at multiple subarctic tundra sites in Alaska, USA, 2013–2014. A single observer processed 2,692 10-minute recordings across 11 site-years. We used time-removal methods to assess availability and used generalized additive models to examine patterns of detectability (joint probability of presence, availability, and detection) for 16 common species. Despite lack of distinct dawn or dusk, most species displayed circadian vocalization patterns, with detection rates generally peaking between 0800 hours and 1200 hours but remaining high as late as 2000 hours for some species. Between 2200 hours and 0500 hours, most species’ detection rates dropped to near 0, signaling a distinctive rest period. Detectability dropped sharply for most species in early July. For all species considered, time-removal analysis indicated nearly 100% likelihood of detection during a 10-minute recording conducted in June, between 0500 hours and 2000 hours. This indicates that non-detections during appropriate survey times and dates were attributable to the species’ absence or that silent birds were unlikely to initiate singing during a 10-minute interval, whereas vocally active birds were singing very frequently. Systematic recordings revealed a gradient of species’ presence at each site, from ubiquitous to incidental. Although the total number of species detected at a site ranged from 16 to 27, we detected only 4 to 15 species on ≥5% of the site’s recordings. Recordings provided an unusually detailed and consistent dataset that allowed us to identify, among other things, appropriate survey dates and times for species breeding at northern latitudes. Our results also indicated that more recordings of shorter duration (1–4 min) may be most efficient for detecting passerines.
Attention to the face is characterised by a difficult to inhibit first fixation to the eyes
The eyes are preferentially attended over other facial features and recent evidence suggests this bias is difficult to suppress. To further examine the automatic and volitional nature of this bias for eye information, we used a novel prompting face recognition paradigm in 41 adults and measured the location of their first fixations, overall dwell time and behavioural responses. First, patterns of eye gaze were measured during a free-viewing forced choice face recognition paradigm. Second, the task was repeated but with prompts to look to either the eyes or the mouth. Participants showed significantly more first fixations to the eyes than mouth, both when prompted to look at the eyes and when prompted to look at the mouth. The pattern of looking to the eyes when prompted was indistinguishable from the unprompted condition in which participants were free to look where they chose. Notably, the dwell time data demonstrated that the eye bias did not persist over the entire presentation period. Our results suggest a difficult-to-inhibit bias to initially orient to the eyes, which is superseded by volitional, top-down control of eye gaze. Further, the amount of looking to the eyes is at a maximum level spontaneously and cannot be enhanced by explicit instructions.
Optimizing surveys of fall-staging geese using aerial imagery and automated counting
Ocular aerial surveys allow efficient coverage of large areas and can be used to monitor abundance and distribution of wild populations. However, uncertainty around resulting population estimates can be large due to difficulty in visually identifying and counting animals from aircraft, as well as logistical challenges in estimating detection probabilities. Photographic aerial surveys can mitigate these challenges and can allow flight at higher altitudes to minimize disturbance of birds and improve safety for surveyors. We evaluated a photographic aerial survey that incorporated a systematic sampling design with automated photo capture and processing for fall-staging geese at Izembek Lagoon, Alaska, in 2017–2019. Ocular aerial surveys have been completed at Izembek Lagoon for >40 years. For the new photo survey, we used a commercial system to automatically trigger cameras at preset points. We then applied a machine-learning algorithm trained to automatically identify and count geese in our photos, manually corrected those counts, and quantified the algorithm's accuracy. We translated corrected counts into density and extrapolated mean density across the entire lagoon to estimate total population size for Pacific brant (Branta bernicla) and cackling geese (B. hutchinsii). The automated algorithm undercounted geese, but successfully identified the small subset of photos containing geese. Manual correction wastherefore needed only for photos automatically identified as containing geese, allowing substantial reduction of workload. Manually-corrected, photo-based estimates of Pacific brant and cackling goose population sizes were larger and more precise than ocular estimates in all 3 years. To reduce costs with little penalty for variance around population estimates, the photographic survey design could be optimized by reducing the number of transects to ~67% of the current number while still manually correcting all photos in which the automated algorithm detected geese. Further years of both ocular and photo surveys would be needed to calibrate the photo estimates against the >40-year timeseries of the ocular survey, after which the photo series could successfully guide management of Pacific brant. As technologies continue to advance, we expect photographic surveys with automated counting to be easily implemented and advantageous to many monitoring programs.
A multiscale assessment of tree avoidance by prairie birds
In North America, grassland bird abundances have declined, likely as a result of loss and degradation of prairie habitat. Given the expense and limited opportunity to procure new grasslands, managers are increasingly focusing on ways to improve existing habitat for grassland birds, using techniques such as tree removal. To examine the potential for tree removal to benefit grassland birds, we conducted 446 point counts on 35 grassland habitat patches in the highly fragmented landscape of west-central Minnesota during 2009–2011. We modeled density of four grassland bird species in relation to habitat composition at multiple scales, focusing on covariates that described grass, woody vegetation (trees and large shrubs), or combinations of grass and woody vegetation. The best-supported models for all four grassland bird species incorporated variables measured at multiple scales, including local features such as grass height, litter depth, and local tree abundance, as well as landscape-level measures of grass and tree cover. Savannah Sparrows (Passerculus sandwichensis), Sedge Wrens (Cistothorus platensis), and Bobolinks (Dolichonyx oryzivorus) responded consistently and negatively to woody vegetation, but response to litter depth, grass height, and grassland extent were mixed among species. Our results suggest that reducing shrub and tree cover is more likely to increase the density of grassland birds than are attempts to improve grass quality or quantity. In particular, tree removal is more likely to increase density of Savannah Sparrows and Sedge Wrens than any reasonable changes in grass quality or quantity. Yet tree removal may not result in increased abundance of grassland birds if habitat composition is not considered at multiple scales. Managers will need to either manage at large scales (80–300 ha) or focus their efforts on removing trees in landscapes that contain some grasslands but few nearby wooded areas.
Impact of encroaching woody vegetation on nest success of upland nesting waterfowl
Grassland managers often regard woody vegetation as hostile habitat that potentially reduces the abundance and fecundity of wildlife that use grasslands. We tested that assumption for waterfowl by examining patterns of nest success on study areas that differed in current extent and previous management of woody vegetation. We located and monitored 1,064 waterfowl nests on 33 federally owned Waterfowl Production Areas (WPAs) in western Minnesota during 2008—2010. Sites contained 0.3—15.1% woodland and also varied markedly in extent of shrubs and scattered trees. Average nest success was low (12.9%), but ranged from 1.5% to 38.7% among site-years. Nests were more likely to succeed when located in landscapes containing more grass (500-m scale) and fewer wetlands (100-m scale), but none of 8 variables measuring woody vegetation were negatively associated with nest survival and 1 variable (abundance of lone trees) was positively associated with nest survival. Our results indicate that management efforts focusing on removing woody vegetation are unlikely to provide improvements in nest survival rates for breeding waterfowl, except to the extent that such management is necessary to maintain large tracts of grassland.
Vectors, Hosts, and Control Measures for Zika Virus in the Americas
We examine Zika virus (ZIKV) from an ecological perspective and with a focus on the Americas. We assess (1) the role of wildlife in ZIKV disease ecology, (2) how mosquito behavior and biology influence disease dynamics, and (3) how nontarget species and ecosystems may be impacted by vector control programs. Our review suggests that free-ranging, non-human primates may be involved in ZIKV transmission in the Old World; however, other wildlife species likely play a limited role in maintaining or transmitting ZIKV. In the Americas, a zoonotic cycle has not yet been definitively established. Understanding behaviors and habitat tolerances of Aedes aegypti and Aedes albopictus , two ZIKV competent vectors in the Americas, will allow more accurate modeling of disease spread and facilitate targeted and effective control efforts. Vector control efforts may have direct and indirect impacts to wildlife, particularly invertebrate feeding species; however, strategies could be implemented to limit detrimental ecological effects.