Human influences on historical and current wildlife distributions from Lewis & Clark to today

Although it is well known that humans are strong modifiers of their environment, there is a need for greater understanding of human-wildlife interactions, both historically as well as currently. Historical journals can help shed light on early human-wildlife interactions, and the Lewis & Clark journals contain some of the earliest and detailed written descriptions of a large part of the United States before Euro-American settlement. I used the journal entries to assess the influence of humans on wildlife distribution and abundance. Areas with denser human population, the Columbia Basin and the Pacific Coast, had lower species diversity and abundance of large mammals. The opposite was observed on the Plains. Overhunting before Euro- American contact accentuated by the introduction of the horse may have been major contributors responsible for the historic absence of some species that are present in the archaeological record. The information gained from the Lewis & Clark journals shows the considerable human influence on wildlife under relatively low human population densities. This has major implications for conservation biology and ecological restoration, since human influence is often underestimated when considering the pre-settlement condition. Species ranges are dynamic and change greatly over time. In order to identify large-scale patterns in range contractions and/or expansions, I compared historic and current geographical ranges of 43 North American carnivores and ungulates. Seventeen of the species had undergone range contractions over >20% of their historic range. In areas of higher human influence, species were more likely to contract and less likely to persist. Species richness declined considerably since historic times, and the temperate grasslands and temperate broadleaf/mixed forest biomes lost the highest average number of species, while the boreal forest and tundra showed fewer numbers of species lost. The study of species range changes contributed new quantitative information about human influences on range contractions in North America. The results can be used to improve our knowledge of historical reference conditions, for the creation of wildlife reserves, and for wildlife re-introductions

The use of remote sensing and Geographic Information Systems (GIS) in assessing changes in stream morphology and vegetation

Remote sensing and Geographic Information Systems (GIS) are well known tools for the study of time change analysis in natural systems. However, long-term studies of riparian systems using large-scale aerial photography are less common. The purpose of this project was to combine large scale aerial photography, GIS, Global Positioning Systems (GPS) and ground truthing for conducting a time change analysis study of an eastern Oregon riparian area over a 20 year time period. The objectives were to assess changes in stream morphology and vegetation that occurred in grazed and exclosed areas from 1979 to 1998. In addition, the viability of using large-scale (1:4000) aerial photography combined with GIS/GPS and ground truthing in this study was evaluated. GIS layers of vegetation and stream morphology parameters were developed from geocorrected images. Ground truthing included the collection of vegetation and stream channel measurements. In addition, older aerial photography and previously collected survey data were available for this study. The area of land changing to water and vice versa was calculated over the 41 ha large study area. This area of change (3.65 ha) was slightly larger than the area of no change (3.2 ha). The length of the thalweg and streambank, sinuosity and stream area remained relatively the same. Most of the changes were associated with the islands. Their number decreased, but their area increased, suggesting an increase in stability. Stream width decreased in both grazed and exclosed sites. Shrub and tree cover increased from 1979 to 1998 over the whole study area from 23% to 34%, and this increase was similar in grazed and exclosed sites. The variability of shrub/tree cover within and between the grazed and exclosed sites was high. Topography and stream dynamics appeared to control changes in stream morphology, including erosion, deposition and island formation. We could find no association between the observed changes and the grazing treatment. The use of large-scale aerial photography, GIS and GPS proved to be a powerful tool for detecting change over time and it is expected that these techniques will become more common in rangeland analysis. It is anticipated that the methods used in this study can be applied to and will help in monitoring of other rangeland streams

The Rise of the Mesopredator

Apex predators have experienced catastrophic declines throughout the world as a result of human persecution and habitat loss. These collapses in top predator populations are commonly associated with dramatic increases in the abundance of smaller predators. Known as “mesopredator release,” this trophic interaction has been recorded across a range of communities and ecosystems. Mesopredator outbreaks often lead to declining prey populations, sometimes destabilizing communities and driving local extinctions.We present an overview of mesopredator release and illustrate how its underlying concepts can be used to improve predator management in an increasingly fragmented world. We also examine shifts in North American carnivore ranges during the past 200 years and show that 60% of mesopredator ranges have expanded, whereas all apex predator ranges have contracted. The need to understand how best to predict and manage mesopredator release is urgent—mesopredator outbreaks are causing high ecological, economic, and social costs around the world

The Membrane Fusion Step of Vaccinia Virus Entry Is Cooperatively Mediated by Multiple Viral Proteins and Host Cell Components

For many viruses, one or two proteins allow cell attachment and entry, which occurs through the plasma membrane or following endocytosis at low pH. In contrast, vaccinia virus (VACV) enters cells by both neutral and low pH routes; four proteins mediate cell attachment and twelve that are associated in a membrane complex and conserved in all poxviruses are dedicated to entry. The aim of the present study was to determine the roles of cellular and viral proteins in initial stages of entry, specifically fusion of the membranes of the mature virion and cell. For analysis of the role of cellular components, we used well characterized inhibitors and measured binding of a recombinant VACV virion containing Gaussia luciferase fused to a core protein; viral and cellular membrane lipid mixing with a self-quenching fluorescent probe in the virion membrane; and core entry with a recombinant VACV expressing firefly luciferase and electron microscopy. We determined that inhibitors of tyrosine protein kinases, dynamin GTPase and actin dynamics had little effect on binding of virions to cells but impaired membrane fusion, whereas partial cholesterol depletion and inhibitors of endosomal acidification and membrane blebbing had a severe effect at the later stage of core entry. To determine the role of viral proteins, virions lacking individual membrane components were purified from cells infected with members of a panel of ten conditional-lethal inducible mutants. Each of the entry protein-deficient virions had severely reduced infectivity and except for A28, L1 and L5 greatly impaired membrane fusion. In addition, a potent neutralizing L1 monoclonal antibody blocked entry at a post-membrane lipid-mixing step. Taken together, these results suggested a 2-step entry model and implicated an unprecedented number of viral proteins and cellular components involved in signaling and actin rearrangement for initiation of virus-cell membrane fusion during poxvirus entry

A procedure for orthorectification of sub-decimeter resolution imagery obtained with an unmanned aerial vehicle (UAV

ABSTRACT Digital aerial photography acquired with unmanned aerial vehicles (UAVs) has great value for resource management due to flexibility and relatively low cost for image acquisition. The very high resolution imagery (5 cm) allows for mapping bare soil and vegetation types, structure and patterns in great detail. While image acquisition is relatively straightforward, the creation of orthorectified, GIS-ready image mosaics presents multiple challenges. Those include relatively small image footprints, image distortion due to the use of low-cost digital cameras, difficulty in locating ground control points and in automatic generation of tie points, and relatively large errors in exterior orientation (camera position and attitude information from the UAV's GPS/IMU). We developed an automated procedure to improve the accuracy of the exterior orientation by matching the UAV images to an orthorectified reference image. Using the UAV reported exterior orientation and camera geometry, combined with the reference image and DEM, the algorithm simulates image acquisition and then computes the covariance between camera image and simulated image pixels. With this evaluation function, a heuristic search algorithm finds successive improvements to the external orientation, ultimately producing a corrected exterior orientation that allows orthorectification with minimal input of tie points and/or ground control points. The RMS error for a 5-cm resolution, 257-image mosaic was 48 cm. Cost and turnaround time for production of orthorectified mosaics from UAV imagery are considerably reduced due to less time and money spent on ground control point and manual tie point collection

Wildlife Encounters by Lewis and Clark: A Spatial Analysis of Interactions between Native Americans and Wildlife

The Lewis and Clark journals contain some of the earliest and most detailed written descriptions of a large part of the United States before Euro-American settlement.We used the journal entries to assess the influence of humans on wildlife distribution and abundance. Areas with denser human population, such as the Columbia Basin and the Pacific Coast, had lower species diversity and a lower abundance of large mammals. The opposite effect was observed on the Plains.We believe that overhunting before Euro-American contact and the introduction of the horse, which heightened the effects of hunting, may have been major contributors to the historical absence of some species that are present in the archaeological record. The results show considerable human influence on wildlife even under relatively low human population densities. This finding has major implications for conservation biology and ecological restoration, as human influence is often underestimated when considering presettlement conditions.Keywords: Predation, Buffer zones, Wildlife distribution, Historical ecology, Lewis and Clar

Defoliation Response of Bluebunch Wheatgrass and Crested Wheatgrass: Why We Cannot Graze These Two Species in the Same Manner

The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform March 202

Classification of Willow Species Using Large-Scale Aerial Photography

The distribution characteristics of willow (genus Salix) can be evaluated with the use of remote sensing, geographic information systems (GIS) technologies, and spatial analysis. This information can be used to better understand willow ecology, such as willow community composition, species relationships, and associations with other landscape attributes (i.e., soils, elevation gradients, water sources, and landscape position). Aerial photographs of a willow-dominated riparian area located in southeastern Oregon were taken in November 1999 at a 1:2 400 scale. Four basic techniques were used to separate willow species from each other in both color and infrared images using ERDAS Imagine® GIS. Willow species included Geyers willow (Salix geyeriana Anderson), Booth willow (Salix boothii Dorn), and Lemmon’s willow (Salix lemmonii Bebb). The techniques used to analyze aerial photographs included image resampling (degrade), image filtering (smoothing), unsupervised classification, and supervised classification. Highest accuracy was obtained using a supervised classification of the color images smoothed with a low-pass convolution filter (84.6% accuracy). Spectral samples were collected using a polygon digitizing method, which had superior results compared to the seed or region growing method. The infrared image was least effective in separating the plants into species classes (58.6% accuracy). This may be due to the lack of the blue band in the infrared image. The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 2020Legacy DOIs that must be preserved: 10.2458/azu_rangelands_v58i6_stringha