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1.
In this article, we describe how protecting vernal pools was discussed by experts in the northeastern United States (U.S) within the context of a theoretical policy framework. We offer insight about characteristics of feasible vernal pool policy solutions, and identify gaps in our understanding, particularly regarding conditions in states currently lacking specific vernal pool protections. Vernal pools are geographically isolated, intermittent wetlands that provide important habitat for a variety of plants and animals. Many may not be federally protected as a result of judicial decisions over the past two decades, and the rule intended to clarify what qualifies for federal protection is currently being reviewed by the courts. Thus, state or local policy approaches may be alternatives to conserving vernal pools. We interviewed vernal pool experts in the northeastern U.S. regarding approaches to vernal pool protection and analyzed their perceptions through the lens of Kingdon's ( 2011 ) multiple streams policy development framework. The framework denotes 13 characteristics of three processes associated with policy development: problem identification, policy solution development, and the impacts of politics. While analyzed for all 13 components, we found participants most often discussed feasibility of policy formulation and implementation, particularly with regard to protecting vernal pools of high value while also remaining within the bounds of what public opinion supports.  相似文献   

2.
ABSTRACT: Variation among Carlson's three TSI values is unsettling to both the public and the scientific communities. Currently, there is no systematic way to account for differences in the three TSI values. Either (or both) of two mechanisms are proposed to account for differing TSI values on a regional basis. The first mechanism simply transforms the Secchi disk and phosphorus information to conform to their respective regional relationship with chlorophyll. The second mechanism uses the three TSI values to identify modifying processes in a lake and may indicate which TSI value (or combination of values) best reflects a lake's trophic condition. The format that is being proposed using information collected from 60 lakes in the Twin Cities (Minnesota) Metropolitan Area can be applied to other regional situations.  相似文献   

3.
/ Of the several automated wetland assessment methods currently available, none are comprehensive in considering all of the primary functions a wetland can perform. We developed a methodology particularly suited to the Northeastern United States that enumerates spatial predictors of wetland function for three primary wetland functions: flood flow alteration, surface water quality improvement, andwildlife habitat. Predictors were derived from several wetland assessment techniques and directly from the literature on wetland structure and function. The methodology was then automated using a Geographic Information System (GIS). The resulting Automated Assessment Method for Northeastern Wetlands (AMNEW) consists of a suite of eight Arc Macro Language (AML) programs that run in the ARC/INFO GRID module. Using remotely sensed land use information and digital elevation models (DEMs), AMNEW produces three separate grids of wetlands that perform each function. The method was tested on four watersheds in Vermont's Lake Champlain Basin. Results and preliminary verification indicate that the method can successfully identify those wetlands in the Northeastern region that have the potential to be functionally important.  相似文献   

4.
/ For regional analyses of species imperilment patterns, data on species distributions are available from the U.S. Fish and Wildlife Service and from the state heritage programs. We compared these two different databases as sources of best available information for regional analyses of patterns of aquatic species imperilment for 132 counties in the southern Appalachians and examined patterns produced from the databases. The heritage program database contained information about a greater number of imperiled species because species need not be federally listed as threatened or endangered to be included in this database. In the southern Appalachians, about half of imperiled molluscs and about one-fourth of imperiled fish were listed as threatened or endangered; much smaller proportions of other taxonomic groups were federally listed. Most threatened and endangered species appeared on both lists, but for about 40% of the species inconsistencies exist, notably a lack of recent records in the heritage program dataset. Numbers of species in each county were significantly different between the two datasets for Georgia, Tennessee, and Virginia, where the largest number of threatened and endangered species reside. Nevertheless, some counties always appeared as centers of imperilment, and the general spatial patterns of imperilment were similar.  相似文献   

5.
Accurate projections of streamflow, which have implications for flooding, water resources, hydropower, and ecosystems, are critical to climate change adaptation and require an understanding of streamflow sensitivity to climate drivers. The northeastern United States has experienced a dramatic increase in extreme precipitation over the past 25 years; however, the effects of these changes, as well as changes in other drivers of streamflow, remain unclear. Here, we use a random forest model forced with a regional climate model to examine historical and future streamflow dynamics of four watersheds across the Northeast. We find that streamflow in the cold season (November–May) is primarily driven by 3-day rainfall and antecedent wetness (Antecedent Precipitation Index) in three rainfall-dominant watersheds, and 30-day rainfall, antecedent wetness, and 30-day snowmelt in the fourth, more snowmelt-dominated watershed. In the warm season (June–October), streamflow is driven by antecedent wetness and rainfall in all watersheds. By the end of the century (2070–2099), cold season streamflow depends on the importance placed on snow in the machine learning model, with changes ranging from −7% (with snow) to +40% (without snow) in a single watershed. Simulated future warm season streamflow increases in two watersheds (56% and 193%) due to increased precipitation and antecedent soil wetness, but decreases in the other two watersheds (−6% and −27%) due to reduced precipitation.  相似文献   

6.
Hathaway, Deborah L., 2011. Transboundary Groundwater Policy: Developing Approaches in the Western and Southwestern United States. Journal of the American Water Resources Association (JAWRA) 47(1):103‐113. DOI: 10.1111/j.1752‐1688.2010.00494.x Abstract: The western and southwestern United States include dozens of groundwater basins that cross political boundaries. Common among these shared groundwater basins is an overlay of differing legal structures and water development priorities, typically, with insufficient water supply for competing human uses, and often, a degraded ecosystem. Resolution of conflicts over ambiguously regulated groundwater has clarified transboundary groundwater policy in some interstate basins, while transboundary groundwater policy in international basins is less evolved. This paper identifies and contrasts approaches to transboundary groundwater policy, drawing from recent conflicts and cooperative efforts, including those associated with the interstate compacts on the Arkansas and Pecos Rivers; the Hueco and Lower Rio Grande Basins shared by New Mexico, Texas, and Mexico; and the Mexicali Basin in California and Mexico. Some efforts seek to fit groundwater policy into existing surface water allocation procedures; some strive for a better fit – incorporating scientific understanding of key differences between groundwater and surface water into policy frameworks. In some cases, neither policy nor precedent exists. The collective experience of these and other cases sets the stage for improved management of transboundary groundwater; as such, challenges and successes of these approaches, and those contemplated in several hypothetical model agreements, are examined.  相似文献   

7.
Future climate and land‐use changes and growing human populations may reduce the abundance of water resources relative to anthropogenic and ecological needs in the Northeast and Midwest (U.S.). We used output from WaSSI, a water accounting model, to assess potential changes between 2010 and 2060 in (1) anthropogenic water stress for watersheds throughout the Northeast and Midwest and (2) native fish species richness (i.e., number of species) for the Upper Mississippi water resource region (UMWRR). Six alternative scenarios of climate change, land‐use change, and human population growth indicated future water supplies will, on average across the region, be adequate to meet anthropogenic demands. Nevertheless, the number of individual watersheds experiencing severe stress (demand > supplies) was projected to increase for most scenarios, and some watersheds were projected to experience severe stress under multiple scenarios. Similarly, we projected declines in fish species richness for UMWRR watersheds and found the number of watersheds with projected declines and the average magnitude of declines varied across scenarios. All watersheds in the UMWRR were projected to experience declines in richness for at least two future scenarios. Many watersheds projected to experience declines in fish species richness were not projected to experience severe anthropogenic water stress, emphasizing the need for multidimensional impact assessments of changing water resources.  相似文献   

8.
9.
Suspended solids or sediments can be pollutants in rivers, but they are also an important component of lotic food webs. Suspended sediment data for rivers were obtained from a United States–wide water quality database for 622 stations. Data for particulate nitrogen, suspended carbon, discharge, watershed area, land use, and population were also used. Stations were classified by United States Environmental Protection Agency ecoregions to assess relationships between terrestrial habitats and the quality and quantity of total suspended solids (TSS). Results indicate that nephelometric determinations of mean turbidity can be used to estimate mean suspended sediment values to within an order of magnitude (r2 = 0.89). Water quality is often considered impaired above 80 mg TSS L–1, and 35% of the stations examined during this study had mean values exceeding this level. Forested systems had substantially lower TSS and somewhat higher carbon-to-nitrogen ratios of suspended materials. The correlation between TSS and discharge was moderately well described by an exponential relationship, with the power of the exponent indicating potential acute sediment events in rivers. Mean sediment values and power of the exponent varied significantly with ecoregion, but TSS values were also influenced by land use practices and geomorphological characteristics. Results confirm that, based on current water quality standards, excessive suspended solids impair numerous rivers in the United States.  相似文献   

10.
Over the last three decades, livestock exclosure research has emerged as a preferred method to evaluate the ecology of riparian ecosystems and their susceptibility to livestock impacts. This research has addressed the effects of livestock exclusion on many characteristics of riparian ecosystems, including vegetation, aquatic and terrestrial animals, and geomorphology. This paper reviews, critiques, and provides recommendations for the improvement of riparian livestock exclosure research. Exclosure-based research has left considerable scientific uncertainty due to popularization of relatively few studies, weak study designs, a poor understanding of the scales and mechanisms of ecosystem recovery, and selective, agenda-laden literature reviews advocating for or against public lands livestock grazing. Exclosures are often too small (<50 ha) and improperly placed to accurately measure the responses of aquatic organisms or geomorphic processes to livestock removal. Depending upon the site conditions when and where livestock exclosures are established, postexclusion dynamics may vary considerably. Systems can recover quickly and predictably with livestock removal (the “rubber band” model), fail to recover due to changes in system structure or function (the “Humpty Dumpty” model), or recover slowly and remain more sensitive to livestock impacts than they were before grazing was initiated (the “broken leg” model). Several initial ideas for strengthening the scientific basis for livestock exclosure research are presented: (1) incorporation of meta-analyses and critical reviews. (2) use of restoration ecology as a unifying conceptual framework; (3) development of long-term research programs; (4) improved exclosure placement/design; and (5) a stronger commitment to collection of pretreatment data.  相似文献   

11.
Abstract: Streambank erosion by mass‐failure processes represents an important form of channel adjustment and a significant source of sediment in disturbed streams. Mass failures regularly occur by a combination of hydraulic processes that undercut bank toes and geotechnical processes that cause bank collapse by gravity. Little if any quantitative information is available on the effectiveness of bank treatments on reducing erosion. To evaluate potential reduction in sediment loadings emanating from streambanks, the hydraulic and geotechnical processes responsible for mass failure were simulated under existing and mitigated conditions using a Bank‐Stability and Toe‐Erosion Model (BSTEM). Two critical erosion sites were selected from each of the three watersheds known to contribute the greatest amounts of fine sediment by streambank processes in the Lake Tahoe Basin. A typical high‐flow annual hydrograph was selected for analysis. Bank‐material strength data were collected for each layer as were species‐specific root‐reinforcement values. The effects of the first flow event on bank‐toe erosion were simulated using an excess shear‐stress approach. The resulting geometry was then exported into the bank‐stability submodel to test for the relative stability of the bank under peak flow and drawdown conditions. In this way, BSTEM was used iteratively for all flow events for both existing and mitigated conditions. On average, 13.6% of the material was eroded by hydraulic shear, the remainder by mass failures, which occurred about five times over the simulation period. Simulations with 1.0 m‐high rock‐toe protection showed a dramatic reduction in streambank erosion (69‐100%). Failure frequency for the simulation period was reduced in most cases to a single episode. Thus, an almost 90% reduction in streambank loadings was achieved by virtually eliminating the erosion of only 14% of the material that was entrained by hydraulic forces. Consequently, simulations show average load reductions of about an order of magnitude. Results stress the critical importance of protecting the bank toe‐region from steepening by hydraulic forces that would otherwise entrain previously failed and in situ bank materials, thereby allowing the upper bank to flatten (by failure) to a stable slope.  相似文献   

12.
Various methods of spatial analysis are commonly used in land-use plans and site selection studies. A historical overview and discussion of contemporary developments of land-use suitability analysis are presented. The paper begins with an exploration into the early 20th century with the infancy of documented applications of the technique. The article then travels through the 20th century, documenting significant milestones. Concluding with present explorations of advanced technologies such as neural computing and evolutionary programming, this work is meant to serve as a foundation for literature review and a premise for the exploration of new advancements as we enter into the 21st century.  相似文献   

13.
The impact of timber management and land-use change on forage production, turkey and deer abundance, red-cockaded woodpecker colonies, water yield, and trout abundance was projected as part of a policy study focusing on the southern United States. The multiresource modeling framework used in this study linked extant timber management and land-area policy models with newly developed models for forage, wildlife, fish, and water. Resource production was integrated through a commonly defined land base that could be geographically partitioned according to individual resource needs. Resources were responsive to changes in land use, particularly human-related, and timber management, particularly the harvest of older stands, and the conversion to planted pine.  相似文献   

14.
The United States and Finland have passed laws to classify and manage Arctic wilderness areas, but their national policies are based on different nature ideologies. Finns tend to perceive wilderness as a human-centered idea, while Americans are inclined to see the same land from a nature-based point of view. Rural residents in the Arctic, and especially indigenous peoples, use motorized vehicles for hunting and gathering in wilderness areas. Attempts of southern-based environmental groups to restrict motor use by imposing a nature-based ideology on rural residents in northern Alaska will result in high levels of political conflict. Alaska land managers need to respect the minority rights of rural residents and a study of wilderness policies in Finnish Lapland is instructive toward this end.  相似文献   

15.
Lake Okeechobee (surface area = 1830 km2, mean depth = 3.5 m), the largest lake in Florida, is eutrophic and has nitrogen and phosphorus loading rates in excess of nearly all established criteria. The lake is not homogeneous regarding trophic conditions, and spatial and temporal variations occur regarding nutrient limitation. Nonetheless, phosphorus loading rate and trophic state data fit reasonably well to various input-output models developed for temperate lakes. Modification of the models by regression analysis to fit data for Florida lakes resulted in improved predictions for most parameters. Analysis of nutrient management alternatives for the lake indicates that a 75% reduction of phosphorus loading from the largest source (the Taylor Creek-Nubbins Slough watershed) would reduce the average chlorophyll a concentration by less than 20%. Complete elimination of inputs from the largest nitrogen source (the Everglades Agricultural Area) would decrease the average nitrogen concentration in the lake by about 20%. Limitations of nutrient inputoutput models regarding analysis of trophic conditions and management alternatives for the lake are discussed.  相似文献   

16.
Following the intent of the National Environmental Policy Act of 1969, many states have adopted policies and procedures directing state agencies and local government units to evaluate the potential environmental impacts of development projects prior to their undertaking. In contrast to a rich literature on federal requirements, current understanding of state environmental review is narrowly focused and outdated. This paper seeks to provide information on the landscape of state environmental review policy frameworks. The paper identifies 37 states with formal environmental review requirements through a document review of state statutes, administrative rules and agency-prepared materials, and confirms this finding through a survey of state administrators. A two-tier classification is used to distinguish states based on the approach taken to address environmental review needs and the scope and depth of relevant policies and procedures implemented. This paper also provides a discussion of policy and programme attributes that may contribute to effective practice, and of the potential for adopting relevant legislation in states where environmental review is currently lacking.  相似文献   

17.
Economic evaluations of restored or enhanced lakes in Florida indicated gravity drawdown was the least expensive action, whereas effluent diversion was 10,000 times more costly on a per hectare basis, with the other lake treatment costs occurring in the following order: gravity drawdown < grass carp introduction < mechanical drawdown < aeration < stormwater control = drawdown-dredging < effluent diversion. Within a particular treatment category, the costs spanned approximately one and one half orders of magnitude. Contrary to the abundant cost data, which permitted an economic analysis, inappropriate statistical design and lack of commitment toward sampling Florida's restored lakes undermines attempts to understand long-term water quality responses to various enhancement techniques. Using Lake Tohopekaliga as a case study, ordinary statistical tests produced contradictory and unreliable interpretations on the effectiveness of drawdown and phosphorus removal at sewage treatment plants in improving the trophic state index. This emphasizes the need for more robust statistical approaches and more detailed data collection in evaluating lake restoration activities It is unfortunate for Florida's lake restoration program that quantitative conclusions based on inferential statistics, replete with tests of assumptions, is limited to very few lakes  相似文献   

18.
Ludwig, Andrea, Marty Matlock, Brian Haggard, and Indrajeet Chaubey, 2012. Periphyton Nutrient Limitation and Maximum Potential Productivity in the Beaver Lake Basin, United States. Journal of the American Water Resources Association (JAWRA) 48(5): 896‐908. DOI: 10.1111/j.1752‐1688.2012.00657.x Abstract: The objectives of this study were to measure periphytic growth responses to enrichment with nitrogen (N), phosphorus (P), and simultaneous N and P using in situ bioassays in streams draining Beaver Reservoir Basin, Northwest Arkansas; compare periphytic growth responses measured with in situ bioassays with a range of land use and point sources; and test the lotic ecosystem trophic status index (LETSI) as a simplifying metric to compare effects of nonpoint‐source pollutant‐limiting variables of N, P, and sediment across the basin. P limitation was observed at sites across a transect of stream orders throughout the basin; however, at the two sites with highest ambient nitrogen concentrations, limitation was often coupled with nitrogen limitation. Nutrients were at nonlimiting levels at both of two sites below wastewater treatment plants in all seasonal deployments. A Michaelis‐Menten growth equation described LETSI as a function of ambient PO4‐P concentrations (p < 0.05); the midpoint (LETSI of 0.50) corresponded with a PO4‐P concentration of approximately 3 μg/l. Change‐point analysis indicated a threshold point at LETSI of 0.80 and 15 μg/l PO4‐P. These low values show that the periphytic community has a high affinity for available P, and that the watershed as a whole is sensitive to available nutrient inputs.  相似文献   

19.
/ Ecological restoration is increasingly invoked as a tool for the maintenance and regeneration of biodiversity. Yet the conceptual foundations and assumptions underlying many restoration management activities are frequently unclear or unstated. Unforeseen, undesirable consequences of restoration activities may emerge as a result. A general conceptual framework for restoration is needed to better accommodate dynamic habitat systems and evolving biota in restoration strategies. A preliminary framework for stream habitat restoration emphasizing stream habitat-biota development is proposed. As developing systems, streams and stream biota exhibit temporal behaviors that change with stream environments. Underlying the dynamic development of streams is potential capacity. Streams express this capacity as an array of habitats over time and across the landscape. Human land uses in the western United States have rapidly altered aquatic habitats and the processes that shape habitat. As a result, the diversity of native fishes and their habitats has been suppressed. Restoration is fundamentally about allowing stream systems to reexpress their capacities. Several steps are provided to guide stream restoration activities. Key tasks include: identification of the historic patterns of habitat development; identification of developmental constraints; relief of those constraints; classification of sensitive, critical, or refuge habitats; protection of the developmental diversity that remains; and monitoring of biotic responses to habitat development. KEY WORDS: Stream habitat; Stream biota; System capacity; System development; Restoration; Classification  相似文献   

20.
/ Regional resource use planning relies on key regional stakeholder groups using and having equitable access to appropriate social, economic, and environmental information and assessment tools. Decision support systems (DSS) can improve stakeholder access to such information and analysis tools. Regional resource use planning, however, is a complex process involving multiple issues, multiple assessment criteria, multiple stakeholders, and multiple values. There is a need for an approach to DSS development that can assist in understanding and modeling complex problem situations in regional resource use so that areas where DSSs could provide effective support can be identified, and the user requirements can be well established. This paper presents an approach based on the soft systems methodology for identifying DSS opportunities for regional resource use planning, taking the Central Highlands Region of Queensland, Australia, as a case study.  相似文献   

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