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81.
While the importance of spatial scale in ecology is well established, few studies have investigated the impact of data grain on conservation planning outcomes. In this study, we compared species richness hotspot and representation networks developed at five grain sizes. We used species distribution maps for mammals and birds developed by the Arizona and New Mexico Gap Analysis Programs (GAP) to produce 1-km2, 100-kmn2, 625-km2, 2500-km2, and 10,000-km2 grid cell resolution distribution maps. We used these distribution maps to generate species richness and hotspot (95th quantile) maps for each taxon in each state. Species composition information at each grain size was used to develop two types of representation networks using the reserve selection software MARXAN. Reserve selection analyses were restricted to Arizona birds due to considerable computation requirements. We used MARXAN to create best reserve networks based on the minimum area required to represent each species at least once and equal area networks based on irreplaceability values. We also measured the median area of each species' distribution included in hotspot (mammals and birds of Arizona and New Mexico) and irreplaceability (Arizona birds) networks across all species. Mean area overlap between richness hotspot reserves identified at the five grain sizes was 29% (grand mean for four within-taxon/state comparisons), mean overlap for irreplaceability reserve networks was 32%, and mean overlap for best reserve networks was 53%. Hotspots for mammals and birds showed low overlap with a mean of 30%. Comparison of hotspots and irreplaceability networks showed very low overlap with a mean of 13%. For hotspots, median species distribution area protected within reserves declined monotonically from a high of 11% for 1-km2 networks down to 6% for 10,000-km2 networks. Irreplaceability networks showed a similar, but more variable, pattern of decline. This work clearly shows that map resolution has a profound effect on conservation planning outcomes and that hotspot and representation outcomes may be strikingly dissimilar. Thus, conservation planning is scale dependent, such that reserves developed using coarse-grained data do not subsume fine-grained reserves. Moreover, preserving both full species representation and species rich areas may require combined reserve design strategies. 相似文献
82.
Tyler A. Hallman W. Douglas Robinson Jenna R. Curtis Edward R. Alverson 《Conservation biology》2021,35(4):1256-1267
Globally, anthropogenic land-cover change has been dramatic over the last few centuries and is frequently invoked as a major cause of wildlife population declines. Baseline data currently used to assess population trends, however, began well after major changes to the landscape. In the United States and Canada, breeding bird population trends are assessed by the North American Breeding Bird Survey, which began in the 1960s. Estimates of distribution and abundance prior to major habitat alteration would add historical perspective to contemporary trends and allow for historically based conservation targets. We used a hindcasting framework to estimate change in distribution and abundance of 7 bird species in the Willamette Valley, Oregon (United States). After reconciling classification schemes of current and 1850s reconstructed land cover, we used multiscale species distribution models and hierarchical distance sampling models to predict spatially explicit densities in the modern and historical landscapes. We estimated that since the 1850s, White-breasted Nuthatch (Sitta carolinensis) and Western Meadowlark (Sturnella neglecta) populations, 2 species sensitive to fragmentation of oak woodlands and grasslands, declined by 93% and 97%, respectively. Five other species we estimated nearly stable or increasing populations, despite steep regional declines since the 1960s. Based on these estimates, we developed historically based conservation targets for amount of habitat, population, and density for each species. Hindcasted reconstructions provide historical perspective for assessing contemporary trends and allow for historically based conservation targets that can inform current management. 相似文献
83.
Allan Curtis 《Environmental management》1998,22(4):563-574
/ With over 2500 Australian Landcare groups, 65,000 volunteer members, and considerable evidence of program impact, Landcare is an important example of state-sponsored rural development in a developed nation. The agency-community partnership is a fundamental element of Landcare and getting the partnership right is vital to long-term program success. After reviewing the emergence of Landcare in the state of Victoria, the author reports research from a 1995 survey of Victorian Landcare groups. Survey information highlighted the extent of agency-group contact, the important roles agency staff played in many Landcare groups, and the positive impact of agency contact and government funding upon group activity. Large majorities of groups reported they were satisfied with their relationship with agency staff. However, a majority of groups reported money or materials provided to manage land and water degradation was inadequate. Recently proposed changes to the Landcare program will provide government funding of work on private property and may address this concern. A majority of groups also reported support for leadership and management training was inadequate and respondents emphasized the need to revise program guidelines that limit funding for group coordinators. This information highlighted the importance of articulating a practical model of community participation in Australia and adopting a systematic approach to providing agency support for Landcare groups. Reflecting upon the Landcare experience, the author suggests some of the key elements of a practical model of state-sponsored citizen resource management contributing to rural development.KEY WORDS: Landcare; Australia; Community participation; Rural development; Citizen resource management; Sustainable agriculture 相似文献
84.
An investigation was conducted regarding the potential economic benefits associated with using a wind turbine to power a groundwater circulation well (GCW) at the former Nebraska Ordnance Plant Superfund site. The first phase of the investigation used a 10‐kilowatt‐rated grid inter‐tie wind turbine to partially offset the purchase of electricity from the utility company. The second phase consisted of the conversion of the grid inter‐tie system to an off‐grid system that stored energy using batteries. During the second phase, the GCW system was operated using either wind turbine power or utility power, and the other system components were operated using utility power. The study showed that a significant amount of power purchased from the utility company was used for nonessential purposes (other than operating the GCW pump and essential treatment components). One nonessential power consumer was the continuous heating of the equipment shelter for operator comfort during their 10‐minute visit every few days. Wind‐turbine reduction in utility power consumption was evaluated, and the operating time of a hypothetical system powered solely by the wind turbine was compared to the actual GCW operating time. This study indicates that retrofitting this GCW system did not economically offset power costs from a cheap, readily available grid system. Perhaps at a remote location with a more energy‐efficient design and operation and the inclusion of green power benefits (in some monetary amount), the wind turbine results will be more favorable. The study of a renewable energy application at the site highlighted opportunities for significant electrical energy savings regardless of the source of the electricity. © 2008 Wiley Periodicals, Inc. 相似文献
85.
M. H. Depledge A.-K. Lundebye T. Curtis A. Aagaard B. B. Andersen 《Marine Biology》1996,126(2):313-319
An Automated Interpulse Duration Assessment system (AIDA) is described which permits detection of irregularities in cardiac rhythms in selected invertebrates. The sensitivity of AIDA was demonstrated by its ability to detect handling stress in mussels (Mytilus edulis) that was not evident when measuring heart rate alone. Changes in cardiac activity patterns of crabs (Carcinus maenas) held in the laboratory for up to 10 wk was also examined using the new technique. The frequency distribution of interpulse duration changed significantly as the nutritional state changed. Potential applications of the AIDA system are discussed. 相似文献
86.
Andrew Curtis Elmore 《补救:环境净化治理成本、技术与工艺杂志》1996,6(2):43-56
Contaminated soil is a continuing source of ground water contamination at some hazardous waste sites. Even if that soil does not pose a threat to human health or the environment, soil remediation may benefit ground-water cleanup in terms of time, money, or protectiveness. A method has been developed to provide a systematic manner to select a soil cleanup alternative. Using commercially available Windows-based software, the method consists of the development of a decision tree whose chance nodes are the restoration time frame probability distributions. Uncertainty associated with site data is quantitatively evaluated using Monte Carlo analysis to develop the probability distributions. The decision tree selects the alternative with the lowest cost. Data from an actual remedial investigation/feasibility study demonstrate the ease and practicality of the selection method. 相似文献
87.
88.
More than 1.5 million traffic crashes involving deer, producing at least $1.1 billion in vehicle damage and about 150 fatalities, are estimated to occur annually in the United States. Deer-related crashes are increasing as both deer populations and vehicular travel increase. Many methods have been used in attempts to reduce deer crashes, often with little scientific foundation and limited evaluation. This article summarizes the methods and reviews the evidence of their effectiveness and the situations in which each may be useful. The only widely accepted method with solid evidence of effectiveness is well-designed and maintained fencing, combined with underpasses or overpasses as appropriate. Herd reduction is controversial but can be effective. Deer whistles appear useless. Roadside reflectors appear to have little long-term effect, although additional well-designed evaluations are needed before firm conclusions can be drawn. Both temporary passive signs and active signs appear promising in specific situations, but considerable research is required to evaluate long-term driver response and to improve and test deer detection technology for active signs. Other methods using advanced technology require substantial additional research and evaluation. 相似文献
89.
Free‐phase light nonaqueous phase liquids (LNAPLs) may be trapped in certain stratigraphic and structural features near or at contaminated sites due to seasonal or other variations in the water table elevation. The purpose of this article is to point out particular subsurface conditions that are conducive to trapping of free‐phase LNAPLs and to suggest approaches to remediating LNAPL‐contaminated sites exhibiting similar subsurface geometry and stratigraphy. To trap free‐phase LNAPL, a structure must have, in addition to closed contours, an upper boundary with pores small enough so that the LNAPL will not enter them. This boundary usually consists of clay‐rich sediments. The Lower Mississippi River Valley contains thousands of these potential traps associated with the geomorphic surfaces mapped as outwash or braided stream terraces, which are covered with thin layers of backswamp clays. These traps may have closure heights ranging from about 1 to 7.5 meters or more and have variable lateral extents. Based on surface geomorphic analysis, the potential LNAPL traps in the Lower Mississippi River Valley range in size from about 0.06 by 0.02 km to 4.19 by 0.69 km. The apparent best remediation strategy for LNAPL sites located on these geomorphic surfaces, which contain these trapping structures, is to first determine if free‐phase is present. If it is present, and is contained in one of the stratigraphic traps, the free‐phase can be removed through an extraction well or wells located at the trap apex. Geomorphic analysis and geophysical surveys may be necessary to accurately locate the trap apex. The remaining residual hydrocarbons might best be remediated using an air sparging system, although it may be necessary to install air vents through the clay cap by backfilling augured holes with washed sand. If it is determined that, due to geometry, the dissolved LNAPL plume cannot be adequately remediated using an air sparging system, then groundwater circulation wells or monitored natural attenuation may be alternative technologies. © 2002 Wiley Periodicals, Inc. 相似文献
90.
Marca Weinberg Cathy A. Lawrence Jamie D. Anderson Jonathan R. Randall Luis W. Botsford Curtis J. Loeb Cedric S. Tadokoro Gerald T. Orlob Paul Sabatier 《Journal of the American Water Resources Association》2002,38(2):367-384
ABSTRACT: This paper brings together spatially and temporally explicit mechanistic models of hydrodynamic, water quality, and ecological processes with an economic model to examine water management alternatives for California's Sacramento River and Delta ecosystem, a large‐scale watershed. Overallocated water supplies in most years, combined with increasing demand for water for environmental purposes, have created a politically charged atmosphere and a need for quantitative assessment of the implications of policy alternatives. By developing and analyzing a common set of policy scenarios, this integrated framework allows us to consider tradeoffs between agricultural economic factors, water quality, and population dynamics for two at‐risk fish species. We analyze two rather extreme types of policy options; one involves structural modifications to change the flow of water within the watershed but no change in water diversions, while the other reallocates water from agricultural users to fish and wildlife. Results suggest that substantial environmental improvements could be made at a relatively modest cost to farmers (1 to 4 percent reductions in revenues) but that those costs could be significant locally. In addition to tradeoffs between farmers and environmental interests, results suggest that policy makers may need to balance competing environmental objectives. 相似文献