Predicting Risk of Habitat Conversion in Native Temperate Grasslands

Abstract: Native grasslands that support diverse populations of birds are being converted to cropland at an increasing rate in the Prairie Pothole Region of North America. Although limited funding is currently available to mitigate losses, accurate predictions of probability of conversion would increase the efficiency of conservation measures. We studied conversion of native grassland to cropland in the Missouri Coteau region of North and South Dakota (U.S.A.) during 1989–2003. We estimated the probability of conversion of native grassland to cropland with satellite imagery and logistic regression models that predicted risk of conversion and by comparing the overlap between areas of high biological value and areas most vulnerable to conversion. Annualized probability of conversion was 0.004, and 36,540 ha of native grassland were converted to cropland during the period of our study. Our predictive models fit the data and correctly predicted 70% of observed conversions of grassland. Probability of conversion varied spatially and was correlated with landscape features like amount of surrounding grassland, slope, and soil productivity. Tracts of high biological value were not always at high risk of conversion. We concluded the most biologically valuable areas that are most vulnerable to conversion should be prioritized for conservation. This approach can be applied broadly to other systems and offers great utility for implementing conservation in areas with spatially variable biological value and probability of conversion.     

The Tribal Environment: Solid Waste in Indian Country

The issue of solid waste management in Indian country is multidimensional in scope because it affects more than just regulatory concerns. There are more than 550 federally recognized Alaska Native and American Indian Tribes in the United States. Tribes are sovereign nations that have a special relationship to the federal government and a unique legal status. The environmental problems faced by tribes are many, and it is only fair that tribes, as sovereigns, specify the levels of protection on their lands. The one-size-fits-all regulatory approach to environmental problems and solid waste management in particular does not work and often leads to conflict between tribes and the federal and state governments. Inherent tensions also exist between tribes and various levels of government concerning jurisdiction of lands and managing solid waste. These intergovernmental relationships are often complex and present unique challenges to all. More research needs to be done on targeting resources to meet the capacity-building needs of tribes, as well as the overall environmental management needs of Indian country under the federal trust obligation. Successful intergovernmental relationships can be fostered through partnership arrangements between tribes and federal, state, and local governments. In the area of solid waste such partnerships have worked. It requires that all levels of government deal with tribes with careful consideration of their cultural, historic, and socioeconomic aspects, which are often intertwined.     

Early Secondary Succession in Bottomland Hardwood Forests of Southeastern Virginia

Addressing the need for reference sites that permit wetland managers to evaluate the relative success of wetland restoration efforts, this project examines the early successional properties of a chronosequence of 17 forested wetlands that have been clear-cut and allowed to naturally revegetate. Ordinations performed on the data using CANOCO software indicated three general types of communities—one dominated by bald cypress (Taxodium distichum) and water tupelo (Nyssa aquatica), one dominated by black willow (Salix nigra), and one with a species composition similar to that of a mature stand of bottomland hardwoods. These divisions were correlated with the percentage of stems originating as coppice on stumps leftover from the clear-cut. In particular, the bottomland hardwood stands were regenerating predominantly as coppice, while the cypress/tupelo and black willow stands were regenerating primarily as seedlings. As indicated by the earlier development of overstory basal area, coppice sites were also regenerating much faster. The hydrology of a site also exhibited a strong impact on the rate of regeneration, with the semipermanently to permanently flooded portions of sites often exhibiting little or no regeneration. The results indicate that, because of the overwhelming reliance on coppice sprouts as the main source of stems and the concomitant enhanced rates of regeneration, certain vegetative parameters of clear-cut bottomland hardwood stands would not be effective benchmarks by which to judge the relative success of creation and restoration efforts.     

Acid Precipitation Effects on Forest Habitats: Implications for Wildlife

Abstract: Forests ecosystems, with their stratified structure, provide a diversity of habitats for a variety of animals. The influence of acidic deposition on forests is being studied intensely, and preliminary research indicates that some forest resources are being affected. These effects and the potential for subsequent change in forest structure and function imply that an impact on the wildlife inhabitants is occurring. In most cases, these impacts are not direct, but instead reflect modifications of habitat and changes in trophic relationships. Detecting changes distinguishable from normal spatiotemporal variations in animal populations is difficult. The net result over time may be reductions or shifts in populations and species composition. This paper provides an overview of current information on the impact of acidic deposition on forest resources as it relates to animals.     

Intraorganizational mobility and work related attitudes

Survey responses of 690 employees of a state agency were used to investigate the idea that internal mobility experiences ‘spill over’ to affect a variety of job attitudes and perceptions. Having one's internal mobility expectations met, as opposed to unmet, was associated with more favorable work-related attitudes, a finding not moderated by demographic factors. Furthermore, employees denied a job change for ‘fair’ reasons generally exhibited more favorable work-related attitudes than those denied for a reason construed as ‘unfair’ (e.g. sex discrimination, reverse discrimination). Demographic characteristics were again observed to moderate few relationships.