Spatial and temporal scales of distribution and demography in breeding songbirds: implications of habitat fragmentation and restoration

Tallgrass prairie has declined throughout the midwestern United States during the past two centuries, and migratory birds breeding in these habitats have also experienced precipitous population declines. One conservation strategy used to mitigate the effects of habitat loss and fragmentation is habitat restoration. I studied how both habitat fragmentation and restoration affect songbird populations breeding in grassland and wetland habitats in northern Iowa, 1999--2002. Most grassland birds tended to be less abundant near edges, yet birds avoided woodland edges more so than other types of edges. Edge avoidance could not be explained by changes in habitat structure. For Bobolinks (Dolichonyx oryzivorus), edge avoidance also increased near corners of sites, where multiple edges converged. These local patterns of edge avoidance were consistent with observed patterns of area sensitivity when scaling patterns up to fragmented landscapes using simulation modeling in neutral (randomized) landscapes. Moreover, regression modeling at landscape scales suggested that edge density metrics were better than landscape compositional metrics at explaining bird density within patches. Habitat restoration provided breeding habitat for many bird species, in which birds tended to occur at high densities in restored patches relative to other land cover types in the landscape. However, demographic data revealed a more complex pattern. In restored wetlands, reproduction was tied closely to interannual climate variation. In particular, nest predation was negatively correlated with water depth in wetlands. In restored grasslands, nest success tended to be relatively low for most species. Population projection models suggested that for Dickcissels (Spiza americana) and, to a lesser extent, Bobolinks, population growth rates were not high enough to be sustainable without immigration into the area (lambda \u3c 1). In addition, population growth was most sensitive to adult survival. Sensitivity to nest predation was moderate and dependent on estimates of survival, while growth was less sensitive to brood parasitism and juvenile survival. Results from this study have improved our understanding of the role of edge effects in generating spatial distributions in landscapes, how restoration ultimately affects avian populations in the Midwest, and it provides a framework for understanding songbird dynamics in fragmented landscapes

Pork Carcass Composition as Influenced by Slaughter Weight

The common goal for those engaged in producing and processing pork should be the efficient production of a product which ultimately is highly desirable to the consumer. This means that any retail pork item must be lean, attractive to the eye and yet be very tasty. This study, concerned with changes in body composition, is a portion of a larger project concerned with more efficient production and utilization of pork

Estimating Detection Probablities of River Birds Using Double Surveys

We describe a method for surveying birds in river habitats that allows for rapid assessment across broad spatial scales and estimation of detection probabilities. Our river survey approach incorporates a double-survey technique, whereby observers in two canoes simultaneously survey birds along a river reach. Data are in the form of a two-sample mark-recapture history, and covariates suspected of influencing detection probabilities can be included in the modeling process and evaluated using information-theoretic approaches. We provide an example using the method along the Madison and upper Missouri rivers in Montana. Overall, detection probabilities for each observer ranged from 57% to 89%, and combined detection probabilities (the likelihood of at least one observer detecting an individual) were consistently high (88% across all species). Detection probabilities across species were positively correlated with body mass. Detection probabilities for some species were influenced by observer, river conditions, and whether species were in groups or alone; groups were more detectable, and individuals in slow-flowing and wide sections of river were more detectable. Boat-based double surveys are a viable method for estimating detection probabilities of birds in river habitats, and double surveys should be considered in other aquatic systems

From DSM to DM-ID

ABSTRACTRecognizing the diagnostic challenges that clinicians face when attempting to arrive at an accurate psychiatric diagnosis for individuals with intellectual and developmental disabilities (IDD) co-occurring with mental illness (MI), in 2007 the National Association for the Dually Diagnosed (NADD), in association with the American Psychiatric Association (APA), published Diagnostic Manual—Intellectual Disability (DM-ID): A Textbook of Diagnosis of Mental Disorders in Persons with Intellectual Disability (Fletcher, Loschen, Stavrakaki, & First, 2007). The DM-ID was designed as a companion to the DSM-IV-TR and aimed to assist clinicians to arrive at a more accurate DSM-IV-TR diagnosis for individuals with IDD. In 2013, the American Psychiatric Association published the DSM-5, thus necessitating revision of the DM-ID to incorporate the changes from the DSM-IV-TR to the DSM-5. The authors discuss the need for and development of the original DM-ID and changes in the DSM-5. The authors then offer insight ..

Making Connections:John Darwin and his Histories of Empire

John Darwin and his Histories of Empir

Counterintuitive Effects of Large-Scale Predator Removal on a Midlatitude Rodent Community

Historically, small mammals have been focal organisms for studying predator–prey dynamics, principally because of interest in explaining the drivers of the cyclical dynamics exhibited by northern vole, lemming, and hare populations. However, many small-mammal species occur at relatively low and fairly stable densities at temperate latitudes, and our understanding of how complex predator assemblages influence the abundance and dynamics of these species is surprisingly limited. In an intact grassland ecosystem in western Montana, USA, we examined the abundance and dynamics of Columbian ground squirrels (Spermophilus columbianus), deer mice (Peromyscus maniculatus), and montane voles (Microtus montanus) on 1-ha plots where we excluded mammalian and avian predators and ungulates, excluded ungulates alone, or allowed predators and ungulates full access. Our goal was to determine whether the relatively low population abundance and moderate population fluctuations of these rodents were due to population suppression by predators. Our predator-exclusion treatment was divided into two phases: a phase where we excluded all predators except weasels (Mustela spp.; 2002–2005), and a phase where all predators including weasels were excluded (2006–2009). Across the entire duration of the experiment, predator and/or ungulate exclusion had no effect on the abundance or overall dynamics of ground squirrels and deer mice. Ground squirrel survival (the only species abundant enough to accurately estimate survival) was also unaffected by our experimental treatments. Prior to weasel exclusion, predators also had no impacts on montane vole abundance or dynamics. However, after weasel exclusion, vole populations reached greater population peaks, and there was greater recruitment of young animals on predator-exclusion plots compared to plots open to predators during peak years. These results suggest that the impacts of predators cannot be generalized across all rodents in an assemblage. Furthermore, they suggest that specialist predators can play an important role in suppressing vole abundance even in lower-latitude vole populations that occur at relatively low densities