A Comparison of Spatial and Spectral Image Resolution for Mapping Invasive Plants in Coastal California

We explored the potential of detecting three target invasive species: iceplant (Carpobrotus edulis), jubata grass (Cortaderia jubata), and blue gum (Eucalyptus globulus) at Vandenberg Air Force Base, California. We compared the accuracy of mapping six communities (intact coastal scrub, iceplant invaded coastal scrub, iceplant invaded chaparral, jubata grass invaded chaparral, blue gum invaded chaparral, and intact chaparral) using four images with different combinations of spatial and spectral resolution: hyperspectral AVIRIS imagery (174 wavebands, 4 m spatial resolution), spatially degraded AVIRIS (174 bands, 30 m), spectrally degraded AVIRIS (6 bands, 4 m), and both spatially and spectrally degraded AVIRIS (6 bands, 30 m, i.e., simulated Landsat ETM data). Overall success rates for classifying the six classes was 75% (kappa 0.7) using full resolution AVIRIS, 58% (kappa 0.5) for the spatially degraded AVIRIS, 42% (kappa 0.3) for the spectrally degraded AVIRIS, and 37% (kappa 0.3) for the spatially and spectrally degraded AVIRIS. A true Landsat ETM image was also classified to illustrate that the results from the simulated ETM data were representative, which provided an accuracy of 50% (kappa 0.4). Mapping accuracies using different resolution images are evaluated in the context of community heterogeneity (species richness, diversity, and percent species cover). Findings illustrate that higher mapping accuracies are achieved with images possessing high spectral resolution, thus capturing information across the visible and reflected infrared solar spectrum. Understanding the tradeoffs in spectral and spatial resolution can assist land managers in deciding the most appropriate imagery with respect to target invasives and community characteristics.     

Impacts of Recreation Trails on Exotic and Ruderal Species Distribution in Grassland Areas Along the Colorado Front Range

This study examines the establishment patterns of exotic and ruderal species along trail corridors in grassland areas of the Colorado Front Range. The effects of trail presence, trail age, and trail traffic levels on exotic and ruderal species establishment are explored to ascertain the potential impacts of trails on surrounding vegetation. Established trails exhibited a greater presence of exotic and ruderal species along the immediate trailside, showing that disturbed trailsides tend to encourage the growth of these species over time. Furthermore, the established trails exhibited significantly less native, nonruderal, and overall species richness at the trailside. These trailside patterns did not show a significant spread away from the trail edge, even after prolonged time periods. Finally, higher trail use tended to hasten the establishment of exotic species along the trailside. The trails did not introduce new species to the recreation areas; rather they acted as reorganizational tools for species that were already present in the study sites.     

Acute toxicity of chlorpyrifos and carbosulfan to glochidia of the freshwater mussel Hyriopsis bialata Simpson, 1900

Environmental Science and Pollution Research - The acute toxicity of carbosulfan and chlorpyrifos in formulated pesticides to glochidia (larvae) of the freshwater mussel (Hyriopsis bialata Simpson,...     

Population Viability Analysis of Spring Chinook Salmon in the South Umpqua River, Oregon

Run sizes of spring chinook salmon in the South Umpqua River in Oregon have declined dramatically since the early part of this century. Habitat degradation is thought to be an important factor contributing to the decline of this stock, and qualitative assessment suggests the stock is at moderate risk of extinction. We use data from this and similar stocks to develop an age-structured, density-dependent model of the population dynamics that incorporates both demographic and environmental stochasticity. Under the assumption of no further habitat destruction, the population is predicted to have a greater than 95% probability of persistence for 200 years. However, sensitivity analysis for the density-dependence estimated from historical run-return data shows that substantially lower predicted viabilities are also statistically consistent with the data. A model that simulates continued habitat degradation results in almost certain extinction within 100 years.     

The Lower Susquehanna River Gorge and Floodplain (U.S.A.) as a Riparian Refugium for Vernal, Forest-Floor Herbs

A survey of vernal, forest-understory herbs was conducted on 52 routes, 10 sample sites each, along the Susquehanna River and its major and minor tributaries in southeastern Pennsylvania and northeastern Maryland. Mature forest stands, as compared to younger successional stands, had a greater diversity and cover of native understory herbs and greater frequencies of K -selected species such as Trillium flexipes and Dicentra canadensis . Vernal herbs with a high fidelity to the river corridor were likely to be more mesic in habitat preference, to occupy a more limited range of habitats, and to be less tolerant to disturbance than species that are also common in adjacent upland areas. The best vernal wildflower sites, which are usually in mesic or floodplain forest, may also be the most vulnerable to species loss if the canopy is removed or the forest is otherwise disturbed. Disturbance-sensitive herbs have been nearly extirpated from the Susquehanna tributaries by very intensive human development. Preservation of an appropriate matrix of microhabitats, particularly along the main river and at the mouths of the creeks, is critical to protecting the vernal flora of the region.     

The effects of type A behavior dimensions and optimism on coping strategy,health, and performance

Type A behavior dimensions and optimism were examined as predictors of health and performance. In addition, this research also explored the ways that Type As and optimists cope with stressful situations. The achievement striving dimension of the Type A behavior pattern and optimism were positively related to class performance, while the anger/hostility dimension was positively related to the health symptom of anxiety. Optimism, on the other hand, was negatively related to anxiety. The interaction of achievement striving and optimism was negatively related to anxiety. Additionally, while achievement striving was positively related to problem-focused coping, irritability showed a negative association with problem-focused coping strategy. The results of this study provide insights for both individuals and organizations regarding how to cope with daily stresses in order to lower health risks and improve performance.     

Housing growth,forests, and public lands in Northern Wisconsin from 1940 to 2000

Rural, forested areas throughout the United States are experiencing strong housing growth with potentially detrimental impacts on the environment. In this paper, we quantify housing growth in Northern Wisconsin over the last sixty years to determine if growth rates were higher near public lands, which may represent an important recreational amenity. We used data from the U.S. Census to produce decadal housing density estimates, “backcasts,” from 1940 to 2000 for northern Wisconsin to examine “rural sprawl” in northern Wisconsin and its relationship to forested areas and public lands. We integrated housing density estimates with the 1992/1993 National Land Cover Dataset to examine the relationship between rural sprawl and land cover, especially forests. Between 1940 and 2000, private land with <2 housing units/km² decreased from 47% to 21% of the total landscape. Most importantly, housing growth was concentrated along the boundaries of public lands. In 14 of the 19 counties that we studied, housing growth rates within 1 km of a public land boundary exceeded growth rates in the remainder of the county, and three of the five counties that did not exhibit this pattern, were the ones with the least amount of public land. Future growth can be expected in areas with abundant natural amenities, highlighting the critical need for additional research and effective natural resource management and regional planning to address these challenges.     

Collisions involving senior drivers: high-risk conditions and locations

OBJECTIVES: To better understand the characteristics of crashes involving senior drivers 65 and older, studies of these crashes were reviewed. METHODS: The review focused primarily on North American studies published since 1990. Studies point to important differences between the crashes of senior drivers and those of younger drivers. RESULTS. Numerous studies have found that senior drivers' crashes are much more likely than crashes of younger drivers to occur at intersections. Senior drivers have particularly high rates of involvement in intersection crashes when they are turning, and even more so when they are turning left. Senior drivers are more likely than younger drivers to have been at fault in these situations, typically because they failed to yield the right-of-way, disregarded the traffic signal, or committed some other traffic violation. Studies also suggest that the extent of overinvolvement of senior drivers in certain types of crashes generally increases with advancing age. CONCLUSIONS. The extent to which the distinctive characteristics of senior drivers' crashes may be due to changing travel patterns associated with aging, or physical or cognitive impairments related to the aging process, is unclear. Further research is needed to understand the pre-crash circumstances of older drivers' intersection crashes.