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311.
Hegetschweiler KT van Loon N Ryser A Rusterholz HP Baur B 《Environmental management》2009,43(2):299-310
Urban forests are popular recreation areas in Europe. Several of these temperate broad-leaved forests also have a high conservation
value due to sustainable management over many centuries. Recreational activities, particularly the use of fireplaces, can
cause extensive damage to soil, ground vegetation, shrubs, and trees. Firewood collection depletes woody debris, leading to
a loss of habitat for specialized organisms. We examined the effects of fireplace use on forest vegetation and the amount
of woody debris by comparing disturbed and control plots in suburban forests in northwestern Switzerland. At frequently used
fireplaces, we found reduced species densities in the ground vegetation and shrub layer and changes in plant species composition
due to human trampling within an area of 150–200 m2. Picnicking and grilling also reduced the height and changed the age structure of shrubs and young trees. The amount of woody
debris was lower in disturbed plots than in control plots. Pieces of wood with a diameter of 0.6–7.6 cm were preferentially
collected by fireplace users. The reduction in woody debris volume extended up to a distance of 16 m from the fire ring, covering
an area of 800 m2 at each picnic site. In order to preserve the ecological integrity of urban forests and to maintain their attractiveness
as important recreation areas, we suggest depositing logging residues to be used as firewood and to restrict visitor movements
near picnic sites. 相似文献
312.
Benjamin M. Jones Christopher D. Arp Kenneth M. Hinkel Richard A. Beck Joel A. Schmutz Barry Winston 《Environmental management》2009,43(6):1071-1084
Lakes are dominant landforms in the National Petroleum Reserve Alaska (NPRA) as well as important social and ecological resources.
Of recent importance is the management of these freshwater ecosystems because lakes deeper than maximum ice thickness provide
an important and often sole source of liquid water for aquatic biota, villages, and industry during winter. To better understand
seasonal and annual hydrodynamics in the context of lake morphometry, we analyzed lakes in two adjacent areas where winter
water use is expected to increase in the near future because of industrial expansion. Landsat Thematic Mapper and Enhanced
Thematic Mapper Plus imagery acquired between 1985 and 2007 were analyzed and compared with climate data to understand interannual
variability. Measured changes in lake area extent varied by 0.6% and were significantly correlated to total precipitation
in the preceding 12 months (p < 0.05). Using this relation, the modeled lake area extent from 1985 to 2007 showed no long-term trends. In addition, high-resolution
aerial photography, bathymetric surveys, water-level monitoring, and lake-ice thickness measurements and growth models were
used to better understand seasonal hydrodynamics, surface area-to-volume relations, winter water availability, and more permanent
changes related to geomorphic change. Together, these results describe how lakes vary seasonally and annually in two critical
areas of the NPRA and provide simple models to help better predict variation in lake-water supply. Our findings suggest that
both overestimation and underestimation of actual available winter water volume may occur regularly, and this understanding
may help better inform management strategies as future resource use expands in the NPRA. 相似文献
313.
An Interval-Parameter Waste-Load-Allocation Model for River Water Quality Management Under Uncertainty 总被引:1,自引:0,他引:1
A simulation-based interval quadratic waste load allocation (IQWLA) model was developed for supporting river water quality
management. A multi-segment simulation model was developed to generate water-quality transformation matrices and vectors under
steady-state river flow conditions. The established matrices and vectors were then used to establish the water-quality constraints
that were included in a water quality management model. Uncertainties associated with water quality parameters, cost functions,
and environmental guidelines were described as intervals. The cost functions of wastewater treatment units were expressed
in quadratic forms. A water-quality planning problem in the Changsha section of Xiangjiang River in China was used as a study
case to demonstrate applicability of the proposed method. The study results demonstrated that IQWLA model could effectively
communicate the interval-format uncertainties into optimization process, and generate inexact solutions that contain a spectrum
of potential wastewater treatment options. Decision alternatives can be generated by adjusting different combinations of the
decision variables within their solution intervals. The results are valuable for supporting local decision makers in generating
cost-effective water quality management strategies. 相似文献
314.
Thomas G. Measham 《Environmental management》2009,43(6):1096-1107
Conventional approaches to evaluation of environmental programs have tended to limit themselves to restricted measures of
program effectiveness. This paper shows how a social learning approach can be incorporated into evaluating public environmental
programs. A social learning approach is particularly suited to complex environmental challenges which are inherently difficult
to understand, predict, and manage, thus complicating the evaluation process. The paper presents an Australian case study
of dryland salinity management where there are major knowledge barriers impeding conventional management techniques. The research
presented in this paper focused on evaluating a public demonstration program to track its impact through its design, implementation,
and monitoring phases. The paper shows that, by incorporating social learning principles and practices, program evaluation
can promote collective action, critical reflection, and increased knowledge to underpin improved environmental management. 相似文献
315.
Silvina Vargas Gil Analia Becker Claudio Oddino Mónica Zuza Adriana Marinelli Guillermo March 《Environmental management》2009,44(2):378-386
Soil microbial populations can fluctuate in response to environmental changes and, therefore, are often used as biological
indicators of soil quality. Soil chemical and physical parameters can also be used as indicators because they can vary in
response to different management strategies. A long-term field trial was conducted to study the effects of different tillage
systems (NT: no tillage, DH: disc harrow, and MP: moldboard plough), P fertilization (diammonium phosphate), and cattle grazing
(in terms of crop residue consumption) in maize (Zea mays L.), sunflower (Heliantus annuus L.), and soybean (Glycine max L.) on soil biological, chemical, and physical parameters. The field trial was conducted for four crop years (2000/2001,
2001/2002, 2002/2003, and 2003/2004). Soil populations of Actinomycetes, Trichoderma spp., and Gliocladium spp. were 49% higher under conservation tillage systems, in soil amended with diammonium phosphate (DAP) and not previously
grazed. Management practices also influenced soil chemical parameters, especially organic matter content and total N, which
were 10% and 55% higher under NT than under MP. Aggregate stability was 61% higher in NT than in MP, 15% higher in P-fertilized
soil, and also 9% higher in not grazed strips, bulk density being 12% lower in NT systems compared with MP. DAP application
and the absence of grazing also reduced bulk density (3%). Using conservation tillage systems, fertilizing crops with DAP,
and avoiding grazing contribute to soil health preservation and enhanced crop production. 相似文献
316.
There is growing concern that recreational shoreline angling activity may negatively impact littoral and riparian habitats
independent of any direct or indirect influences of fish harvest or fishing mortality through mechanisms such as disturbance
(e.g., trampling, erosion) and pollution (e.g., littering). We sampled a suite of aquatic and terrestrial variables (i.e.,
water quality, aquatic and terrestrial macrophytes, soil compaction, anthropogenic refuse) at 14 high shoreline angling-activity
sites (identified by way of interviews with conservation officers and angling clubs) within an urban area (Ottawa, Canada).
For each high angling-activity site, a nearby corresponding low angling-activity site was sampled for comparison. We found
that the percentage of barren area and soil compaction were greater in areas of high angling activity compared with areas
that experienced relatively low angling activity. In addition, terrestrial and aquatic macrophyte density, height, and diversity
were lower at high angling-activity sites. Angling- and non-angling-related litter was present in large quantities at each
of the high angling-activity sites, and comparatively little litter was found at low angling-activity sites. Collectively,
these findings indicate that shoreline angling does alter the riparian environment, contributing to pollution and environmental
degradation in areas of high angling intensity. With growing interest in providing urban angling opportunities and in response
to increasing interest in developing protected areas and parks, a better understanding of the ecologic impacts of shoreline
angling is necessary to address multiuser conflicts, to develop angler outreach and educational materials, and to optimize
management of angling effort to maintain ecologic integrity of riparian and aquatic ecosystems. 相似文献
317.
Dongmei Han Xing Liang Menggui Jin Matthew J. Currell Ying Han Xianfang Song 《Environmental management》2009,44(2):243-255
Based on analysis of groundwater hydrochemical and isotopic indicators, this article aims to identify the groundwater flow
systems in the Yangwu River alluvial fan, in the Xinzhou Basin, China. Groundwater δ2H and δ18O values indicate that the origin of groundwater is mainly from precipitation, with local evaporative influence. d-excess values lower than 10% in most groundwaters suggest a cold climate during recharge in the area. Major ion chemistry,
including rCa/rMg and rNa/rCl ratios, show that groundwater salinization is probably dominated by water–rock interaction (e.g.,
silicate mineral weathering, dissolution of calcite and dolomite and cation exchange) in the Yangwu River alluvial fan, and
locally by intensive evapotranspiration in the Hutuo River valley. Cl and Sr concentrations follow an increasing trend in
shallow groundwater affected by evaporation, and a decreasing trend in deep groundwater. 87Sr/86Sr ratios reflect the variety of lithologies encountered during throughflow. The groundwater flow systems (GFS) of the Yangwu
River alluvial fan include local and intermediate flow systems. Hydrogeochemical modeling results, simulated using PHREEQC,
reveal water–rock interaction processes along different flow paths. This modeling method is more effective for characterizing
flow paths in the intermediate system than in the local system. Artificial exploitation on groundwater in the alluvial fan
enhances mixing between different groundwater flow systems. 相似文献
318.
Alan T. Herlihy Jean Sifneos Chris Bason Amy Jacobs Mary E. Kentula M. Siobhan Fennessy 《Environmental management》2009,44(2):369-377
We sampled 92 wetlands from four different basins in the United States to quantify observer repeatability in rapid wetland
condition assessment using the Delaware Rapid Assessment Protocol (DERAP). In the Inland Bays basin of Delaware, 58 wetland
sites were sampled by multiple observers with varying levels of experience (novice to expert) following a thorough training
workshop. In the Nanticoke (Delaware/Maryland), Cuyahoga (Ohio), and John Day (Oregon) basins, 34 wetlands were sampled by
two expert teams of observers with minimal protocol training. The variance in observer to observer scoring at each site was
used to calculate pooled standard deviations (SDpool), coefficients of variation, and signal-to-noise ratios for each survey. The results showed that the experience level of
the observer had little impact on the repeatability of the final rapid assessment score. Training, however, had a large impact
on observer to observer repeatability. The SDpool in the Inland Bay survey with training (2.2 points out of a 0–30 score) was about half that observed in the other three basins
where observers had minimal training (SDpool = 4.2 points). Using the results from the survey with training, we would expect that two sites assessed by different, trained
observers who obtain DERAP scores differing by more than 4 points are highly likely to differ in ecological condition, and
that sites with scores that differ by 2 or fewer points are within variability that can be attributed to observer differences. 相似文献
319.
Stamatis Zogaris Alcibiades N. Economou Panayotis Dimopoulos 《Environmental management》2009,43(4):682-697
Ecoregion delineations have gained increased attention in Europe, especially following the Water Framework Directive 2000/60/EC
(WFD), which provides the European Union’s first policy-relevant ecoregion map. However, the WFD’s ecoregions were created
through a minor adaptation of Illies’ (Limnofauna Europaea. Gustav Fisher Verlag, Stuttgart, 1967/1978) freshwater zoogeographic
regions, and the map’s specific boundaries have not been widely evaluated with respect to the WFD’s uses or their biogeographic
accuracy. We examined the WFD ecoregion boundaries in Greece and its neighboring Balkan states by comparing them with the
most prominent freshwater biogeographic boundaries as shown by riverine freshwater fish assemblages. Classification and ordination
analyses of 23 river basin fish assemblages helped delineate natural faunal break boundaries in freshwater species assemblage
distributions depicting major biogeographic barriers to aquatic biota dispersal. However, these biogeographic boundaries differ
from those delineated in the WFD map, suggesting boundary errors and inconsistencies in the delineation method of the WFD
ecoregions. We reviewed specific boundary disagreements and produced a map showing the region’s most prominent freshwater
biogeographic boundaries by charting them on watershed borders among the four biotically dissimilar river basin groups in
the southern Balkans. This regional evaluation reveals both a need to reconcile disparate approaches to ecoregion mapping
and to promote the development of a new policy-relevant inland waters ecoregion framework that would support broad-scale water
management and aquatic conservation. 相似文献
320.
Ecological disturbances of forests by insects have a complex array of associated human dimensions presenting complications
for natural resource decision making and relationships between stakeholders and managers. This article discusses the human
context of forest disturbances by insects by reviewing four cases of bark beetle forest disturbance from British Columbia
in Canada, Bavarian Forest National Park in Germany, the Kenai Peninsula in Alaska, and the north central region of Colorado.
Findings and lessons learned from these studies are outlined along with their implications for managing forest disturbances
by insects in general. Conclusions focus on the need to assess the broad array of impacts and risks perceived by local residents
and the capacity for local action and involvement in managing forest disturbances. Communication and interaction between resource
managers and local stakeholders can facilitate the identification of management priorities and potentially reduce some of
the risks associated with forest disturbances by insects. 相似文献