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11.
Fluctuations of bird abundances in the Midwest region of the United States have been attributed to such factors as landscape change, habitat fragmentation, depredation, and supplemental feeding. However, no attempt has been made to estimate the collective role of landowner activities that may influence birds across a landscape. To investigate how landowners might influence birds when the majority (> 90%) of land is privately owned, we surveyed all 1694 private domestic landowners living on three breeding bird survey routes (120 km) that represent a continuum of rural-to-urban landscapes in Southeastern Michigan from October through December 2000. Our survey was designed to investigate (1) the proportion of landowners involved in bird feeding, providing bird houses, planting or maintaining vegetation for birds, gardening, landscaping, applying fertilizer, and applying pesticides or herbicides; (2) whether differences existed between urban, suburban, and rural landowner activities; and (3) whether landowners that carried out a given activity were sociodemographically different from those who did not. Of the 968 respondents (58.5% response rate), 912 (94%) carried out at least one of the activities on their land and the average landowner carried out 3.7 activities. A total of 65.6% fed birds, 45.7% provided bird houses, 54.6% planted or maintained vegetation for birds, 72.7% gardened, 72.3% landscaped, 49.3% applied fertilizer, and 25.2% applied pesticides or herbicides. Significant differences existed between the landscapes, with rural landowners having more bird houses and applying pesticides or herbicides in greater frequency. Similarly, urban landowners had a greater density of bird feeders and houses, but planted or maintained vegetation in the lowest frequency. Participation in activities varied by demographic factors, such as age, gender, and occupation. Scaling each activity to all landowners, including nonrespondents, across all landscapes indicates that between 14% and 82% of landowners may be engaged in a particular activity, with application of pesticides or herbicides having the least potential involvement (13.9%–55.4%) and gardening having the greatest potential involvement (40.1%–81.6%). Taken collectively, our results indicate that landowners are both intentionally and unintentionally engaged in a wide range of activities that are likely to influence bird populations. 相似文献
12.
For the last 20 years, human–wildlife conflicts have been rapidly increasing in towns. Although people want “greener” cities,
the expansion of disliked species causes problems that are difficult to manage and to reduce. The complexity of the numerous
factors involved in these human–wildlife relations needs the development of a comprehensive tool for urban planners. Today,
with the development of computers and geographical information systems, it is easier to analyze and combine different spatial
data as methods used for the management of risks in studies of natural hazards. Here we present a method for assessing and
mapping the risk in cases of human–wildlife conflict. An application to starling management in a town in western France will
show the efficiency of our methods to combine information given by a network of experts and to highlight higher risk sites.
The map of risk provides a spatial result useful for comprehension, communication between people and agencies, and public
education. 相似文献
13.
Sid Gautam 《Journal of the American Water Resources Association》1976,12(5):1061-1070
ABSTRACT: During the last 27 years of independence, a large number of inter-state water disputes cropped up over the use of rivers. Surprisingly enough, more disputes developed in this short period than in the earlier 200 years of the development of irrigation and so far none of the disputes has been permanently solved. The major rivers of India are all inter-state rivers and this is one of the more important reasons why some of them are not yet fully developed for irrigation or power production. The Union Government has set up, so far, only three tribunals to adjudicate inter-state disputes. But the problems do not end simply by setting up the tribunals. In practice, it has also proved a dilatory process. None of the tribunals has been successful in settling any dispute in the long years of their existence. There is no codified law prescribing rights and the notion of “equity” has come to prevail restraining the upper states from drawing such quantities of water as would injure the interests of the lower states. Though the general principle of equitable apportionment had been advocated many times, in practice each contending state had given this principle an interpretation that suited it. The basic principle would be to harness the rivers not for the benefit of a particular state but for the maximization of agricultural, industrial, and navigational potential in the areas served by the rivers. 相似文献
14.
David M. Greer 《Environmental management》1982,6(3):217-229
An urban population of ducks in Puyallup, Washington, USA was studied for 14 consecutive months beginning in November 1978. Observations were made weekly from four study sites where ducks would congregate at early morning hours. Factors contributing to the presence of waterfowl in Puyallyup included abundant food supplies and a creek corridor that connected fragmented habitats in the urban area to the larger rural populations of waterfowl. Mallards (Anas platyrhynchos) were the most abundant of the 13 species observed and were the only ducks remaining during the nesting season. Habitat size and complexity were important factors influencing the species diversity of a particular site. Nesting success of mallards was poor due to limited distribution of nesting habitat, intraspecific aggression, and human disturbance. Both site-specific and more broad-based strategies are suggested for managing and planning for duck populations in urban areas. 相似文献
15.
Newton M Cole EC Tinsley IJ 《Environmental science and pollution research international》2008,15(7):573-583
Background, aim, and scope Large-scale deforestation is occurring in subarctic North America following clearing by salvage logging or insect attack.
Numerous shrubs, herbs, and deciduous tree species tend to dominate areas on which stands of white spruce have grown. In the
absence of economically advantageous mechanical methods, several herbicides have value in efforts to reforest by planting
white spruce. Glyphosate, imazapyr, triclopyr, and hexazinone are all capable of selectively removing many competing species,
but there is concern about whether they would degrade naturally or persist owing to the frigid climate.
Materials and methods We established test plots with all four herbicides in upland and river bottom sites at 65°N and 58°N latitudes. The northern
site has extremely cold winters, with soils that freeze to a depth of 1–2 m, and precipitation of 275 mm/year. The southern
site has heavy rain and snowfall, amounting to 2,250 mm/year evenly distributed. Soil seldom freezes deeply. On each test
plot, one of the four herbicides was applied at twice the normal operational use rate to facilitate detection. They were applied
at the normal timing, with hexazinone, imazapyr, and triclopyr applied in June and glyphosate applied in fall. Soils were
sampled immediately after treatment and those samples used as references for dissipation data gathered over the next 11–14 months
from soil 0- to 15- and 15- to 45-cm depths.
Results Dissipation rates did not follow first-order rates because freezing conditions slowed most microbial activity. All products
dissipated to close to or below detection limits within the time of the study. Dissipation from vegetation was substantially
more rapid and depended on the nature of the plants treated as well as the product used. While soil residues dissipated more
slowly than in temperate regions, they did display consistent dissipation patterns during above-freezing conditions and also
the influence of microbial activity. Mobility was very limited with all products but hexazinone.
Discussion These products dissipate during summer in high latitudes much as they would in temperate climates. Winter changes are small,
but are not unlike some changes reported elsewhere under freezing conditions. Unlike many other studies, soil water did not
influence dissipation heavily, but the high latitude and semi-arid climate also did not create severely droughty soils. Residues
in plants were much higher than those in soils, but denatured the vegetation quickly, leading to unsuitability for forage
in any case.
Conclusions Low toxicity of these products and their metabolites combined with consistent dissipation and low mobility suggest that toxic
hazard of their use at high latitudes need not be a matter of serious concern to humans, terrestrial wildlife, or aquatic
systems. They are safe for use in management and rehabilitation of boreal forests when used properly.
Recommendations and perspectives Dissipation at rates approaching those in warmer climates offer a hypothesis that microflora native to high latitudes may
be adapted to destruction of such molecules at lower temperatures than may be indicated by experiments with microflora adapted
to warmer climates. Residues pose no observable risk to wildlife or humans in the area of use when products are applied properly.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available for authorized users. 相似文献
16.
Analysis tools that combine large spatial and temporal scales are necessary for efficient management of wildlife species,
such as the burrowing owl (Athene cunicularia). We assessed the ability of Ripley’s K-function analysis integrated into a geographic information system (GIS) to determine changes in burrowing owl nest clustering
over two years at NASA Ames Research Center. Specifically, we used these tools to detect changes in spatial and temporal nest
clustering before, during, and after conducting management by mowing to maintain low vegetation height at nest burrows. We
found that the scale and timing of owl nest clustering matched the scale and timing of our conservation management actions
over a short time frame. While this study could not determine a causal link between mowing and nest clustering, we did find
that Ripley’s K and GIS were effective in detecting owl nest clustering and show promise for future conservation uses. 相似文献
17.
Current political conditions, primarily budgetary uncertainty, and the related reluctance to make funding commitments for
future generations, have raised questions about the costs of conservation and environmental protection that have not previously
been asked. As Federal investments are scrutinized and budgets become ever more constrained, the costs associated with environmental
requirements could begin to be of greater importance and to influence decisions on Federal projects. In response to concerns
about the U.S. Army Corps of Engineers (Corps) spending under the Endangered Species Act (P.L. 93-205) (ESA), a limited investigation
was performed to determine the accuracy of reported Corps expenditures. The investigation showed that, for particular groups
of species, actual conservation costs for threatened and endangered species may be twice the amounts previously reported in
the annual ESA expenditure reporting to the U.S. Fish and Wildlife Service. In light of this finding, the Corps has sought
a means to provide more accurate and consistent reporting of expenditures for addressing threatened and endangered species.
A Species Costs Template (template) has been developed to identify the types and magnitude of costs related to the ESA and
to counteract the impediments (legal, institutional, and practical) to underreporting costs. The template will be used by
the Corps for reporting ESA costs beginning with Fiscal Year 2005 (FY05) (reported in January 2006). Five broad categories
of expenditures (effects determination costs, ESA protection and conservation costs, equipment costs, opportunity costs, and
other species costs) are identified by the template. 相似文献
18.
Benjamin K. Sovacool 《Environment, Development and Sustainability》2007,9(2):187-201
Contrary to claims from American politicians, lobbyists, and oil and gas executives, allowing energy development in the Alaskan
Arctic National Wildlife Refuge (ANWR) will harm the environment, compromise international law, erode the social significance
of wilderness protection, and ultimately fail to␣increase the energy security of the United States. After exploring a brief
history of the ANWR controversy, this piece argues that the operation of oil and gas refineries in ANWR will release discharged
solids, drilling waste, and dirty diesel fuel into the ecosystem’s food-chain, as they have from oil operations in Prudhoe
Bay. Less obvious but equally important, oil and gas exploration in ANWR will violate a number of international treaties on
biodiversity protection. In the end, development in ANWR will threaten the concept of wilderness protection, and will do little
to end US dependence on foreign sources of energy.
About the Author: Benjamin K. Sovacool is a doctoral candidate in the Department of Science and Technology Studies at the Virginia Polytechnic
Institute & State University in Blacksburg, Virginia. He works as a research analyst for the Consortium on Energy Restructuring
and is a Senior Research Fellow for the Virginia Center for Coal and Energy Research. He also just completed a Graduate Fellowship
in Energy Policy at the Oak Ridge National Laboratory in Oak Ridge, Tennessee.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
19.
Hydrologic analysis for coastal wetland restoration 总被引:1,自引:0,他引:1
Increasing recognition of the value of tidal wetlands has led to interest in how to restore and enhance areas that have been modified by human activity. The policy of recognizing restoration or enhancement as mitigation for destruction of other wetlands is controversial. Once policy questions are separated from technical questions, the steps in a successful project are straightforward A key element in the design of a successful project is quantitative hydraulic and hydrologic analysis of alternatives. Restoration projects at two sites in California used a combination of empirical geomorphic relationships, numerical modeling, and verification with field observations. Experience with these and other wetland restoration projects indicates the importance of longterm postproject monitoring, inspection, and maintenance 相似文献
20.
Silvicultural guidelines are presented for the management of intermountain Douglas-fir (Pseudotsuga menziesii) stands for sawtimber production and goshawk (Accipiter gentilis) nesting habitat in the northern Rocky Mountains. Data from 14 goshawk nest stands in Douglas-fir forests on the Targhee
National Forest in Idaho (Patla 1991) were used to characterize the range of stand conditions considered suitable for goshawk
nesting. A density management regime is presented using Reineke's stand density index that includes a technical rotation designed
to produce sawlogs with a single commercial thinning. On average timber-growing sites, stands reach goshawk habitat suitability
when site height is 25 m at age 75 and provide 65 years of goshawk nesting habitat until the final harvest at age 140. Approximately
1320 m3/ha are harvested over the rotation. On higher-quality sites, rotation length declines from 140 to 85 years, of which roughly
35 years are suitable for goshawk nesting. 相似文献