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991.
Mgidi TN Le Maitre DC Schonegevel L Nel JL Rouget M Richardson DM 《Journal of environmental management》2007,84(2):173-187
Plant invasions are a serious threat to natural and semi-natural ecosystems worldwide. Most management-orientated research on invasions focuses on invaders that are already widespread and often have major impacts. This paper deals with "emerging" invaders-those alien species with the potential to become important problems without timely intervention. A climate matching procedure was developed to define areas of South Africa, Lesotho and Swaziland that could be invaded by 28 plant species that had previously been classified as emerging invaders. Information on the location of populations of these species in the study area was combined with information on their distributions (as native or alien) in parts of Australia and the United States of America. These two countries had the best available distribution data for this study. They also share many invasive alien plant species with South Africa. Climatic data obtained for weather stations near points of known occurrence in these countries were used to define the climatically suitable areas for each species in the study area. Almost 80% of the remaining natural environment in southern Africa was found to be vulnerable to invasion by at least one of these species, 50% by six or more and 24% by 16 or more species. The most vulnerable areas are the highveld grasslands and the eastern escarpment. The emerging invaders with the greatest potential range included Acacia podalyriifolia and Cortaderia selloana. The globally important invaders Ulex europaeus and Lythrum salicaria had a more limited invasion potential but could still become major invaders. There was no relationship between the extent of the climatically suitable areas for the different species and an expert ranking of their invasion potential, emphasising the uncertainties inherent in making expert assessments based on very little information. The methods used in this analysis establish a protocol for future modelling exercises to assess the invasion potential of other emerging invaders. 相似文献
992.
Gerzabek MH Barceló D Bellin A Rijnaarts HH Slob A Darmendrail D Fowler HJ Négrel P Frank E Grathwohl P Kuntz D Barth JA 《Journal of environmental management》2007,84(2):237-243
The integrated project "AquaTerra" with the full title "integrated modeling of the river-sediment-soil-groundwater system; advanced tools for the management of catchment areas and river basins in the context of global change" is among the first environmental projects within the sixth Framework Program of the European Union. Commencing in June 2004, it brought together a multidisciplinary team of 45 partner organizations from 12 EU countries, Romania, Switzerland, Serbia and Montenegro. AquaTerra is an ambitious project with the primary objective of laying the foundations for a better understanding of the behavior of environmental pollutants and their fluxes in the soil-sediment-water system with respect to climate and land use changes. The project performs research as well as modeling on river-sediment-soil-groundwater systems through quantification of deposition, sorption and turnover rates and the development of numerical models to reveal fluxes and trends in soil and sediment functioning. Scales ranging from the laboratory to river basins are addressed with the potential to provide improved river basin management, enhanced soil and groundwater monitoring as well as the early identification and forecasting of impacts on water quantity and quality. Study areas are the catchments of the Ebro, Meuse, Elbe and Danube Rivers and the Brévilles Spring. Here we outline the general structure of the project and the activities conducted within eleven existing sub-projects of AquaTerra. 相似文献
993.
Sullivan TJ Moore JA Thomas DR Mallery E Snyder KU Wustenberg M Wustenberg J Mackey SD Moore DL 《Environmental management》2007,40(6):958-965
An experimental study was conducted in Tillamook, Oregon, USA, to quantify the effectiveness of edge-of-field vegetated buffers
for reducing transport of fecal coliform bacteria (FCB) from agricultural fields amended with dairy cow manure. Installation
of vegetated buffers on loamy soils dramatically reduced the bacterial contamination of runoff water from manure-treated pasturelands,
but the size of the vegetated buffer was not an important determinant of bacterial removal efficiency. Only 10% of the runoff
samples collected from treatment cells having vegetated buffers exhibited FCB concentrations >200 colony forming units (cfu)/100
mL (a common water quality standard value), and the median concentration for all cells containing vegetated buffers was only
6 cfu/100 mL. The presence of a vegetated buffer of any size, from 1 to 25 m, generally reduced the median FCB concentration
in runoff by more than 99%. Results for FCB load calculations were similar. Our results suggest that where substantial FCB
contamination of runoff occurs from manure-treated pasturelands, it might be disproportionately associated with specific field
or management conditions, such as the presence of soils that exhibit low water infiltration and generate larger volumes of
runoff or the absence of a vegetated buffer. Buffer size regulations that do not consider such differences might not be efficient
or effective in reducing bacterial contamination of runoff. 相似文献
994.
The invasion of water hyacinth (Eichhornia crassipes) has resulted in enormous ecological and economic consequences worldwide. Although the spread of this weed in Africa, Australia,
and North America has been well documented, its invasion in China is yet to be fully documented. Here we report that since
its introduction about seven decades ago, water hyacinth has infested many water bodies across almost half of China’s territory,
causing a decline of native biodiversity, alteration of ecosystem services, deterioration of aquatic environments, and spread
of diseases affecting human health. Water hyacinth infestations have also led to enormous economic losses in China by impeding
water flows, paralyzing navigation, and damaging irrigation and hydroelectricity facilities. To effectively control the rampage
of water hyacinth in China, we propose a sustainability science-based management framework that explicitly incorporates principles
from landscape ecology and Integrated Pest Management. This framework emphasizes multiple-scale long-term monitoring and research,
integration among different control techniques, combination of control with utilization, and landscape-level adaptive management.
Sustainability science represents a new, transdisciplinary paradigm that integrates scientific research, technological innovation,
and socioeconomic development of particular regions. Our proposed management framework is aimed to broaden the currently dominant
biological control-centered view in China and to illustrate how sustainability science can be used to guide the research and
management of water hyacinth. 相似文献
995.
Copper is the biocide of choice for present-day antifouling (AF) paints. It is also a major source of copper loading in to
the marine environment and, as such, might cause local copper levels to exceed water quality criteria. The present study is
multifaceted and looks into the overall impact of copper-based AF paints on copper concentrations along a 64-km stretch of
the Indian River Lagoon and at Port Canaveral, Florida. This preliminary study is one of the first to outline issues and present
background evidence on the current status of copper and copper-based AF usage in Florida and to address the need for management.
Previous measurements of copper levels in these waters show a history of copper contamination close to marinas, boatyards,
and at Port Canaveral that often exceed state and federal water quality standards. Further, we estimate that the total annual
copper input into the Indian River Lagoon is between 1.7 tons/year (sailboats) and 2.1 tons/year (powerboats) from boats in
14 marinas. We estimate the copper input into Port Canaveral to be about 1.4 tons/year from seven cruise ships. A brief survey
of marina operators and boat owners revealed attitudes and practices associated with AF paint usage that ranged from excellent
to inferior. Management recommendations are made for a proactive approach to improving AF paint selection and application,
assessing the environmental status of copper, and redefining existing management practices for sustainable AF paint usage
and environmental health. 相似文献
996.
The proximity principle—disposing of waste close to its origin—has been a central value in municipal solid waste (MSW) management
in Japan for the last 30 years and its widespread adoption has helped resolve numerous “Not in My Backyard” issues related
to MSW management. However, MSW management costs have soared, in large part because of aggressive recycling efforts and because
most MSW is incinerated in a country that has scarce landfill capacity. In addition, smaller, less sophisticated incinerators
have been closed because of high dioxin emissions. Rising costs combined with the closure of smaller incinerators have shifted
MSW management policy toward regionalization, which is the sharing of waste management facilities across municipalities. Despite
the increased use of regionalized MSW facilities, the proximity principle remains the central value in Japanese MSW management.
Municipal solid waste management has become increasingly regionalized in the United States, too, but different driving forces
are at work in these two countries. The transition to regionalized MSW management in Japan results from strong governmental
control at all levels, with the central government providing funds and policy direction and prefectures and municipalities
being the primary implementing authorities. By contrast, market forces are a much stronger force with US MSW management, where
local governments—with state government oversight—have primary responsibility for MSW management. We describe recent changes
in Japan’s MSW programs. We examine the connections between MSW facility regionalization, on the one hand, and, on the other
hand, the proximity principle, coordination among local governments, central government control, and financing mechanisms. 相似文献
997.
The structure and advancement of woody vegetation was studied in a semi-arid rangeland of southern Ethiopia under three land-use systems (communal land, a government ranch and a traditional grazing reserve enclosure) and along a distance gradient (near, middle and far) from water sources. A total of 54 woody plant species were identified. Based on the subjective opinions of the pastoralists, 85% of the identified woody plants have forage values to livestock. Cadaba farinsoa, Ormocarpum trichocarpum, Rhus natalensis, Acacia brevispica, Cordia gharaf and Hibiscus sparseaculeatus were reported to have fair to good palatability. Tree equivalent (TE) density of all woody plants combined was greater (P <0.01) in the government ranch (1) 188 TE ha(-1)) and the communal land (1083 TE ha(-1)) than in the traditional grazing reserve (419 TE ha(-1)), whereas this did not vary significantly (P >0.05) along the distance gradient from water. The most important encroaching woody plant species in the study areas were in descending order: Commiphora africana, Acacia drepanolobium, A. brevispica, Acacia. tortilis, Grewia tembensis and Lannea floccosa. The density of individual encroaching woody plant species along the distance gradient from water was not consistent. All encroaching woody species had the highest TE density in the communal land. The prevalence of these species followed the pattern of intensity of use within the communal grazing area. Most of the woody species had the highest abundance in the height class >0-2m regardless of land use and distance gradient from water. This study investigated the advance of severe woody encroachment in the communal and government sites as well as along the distance gradient from water. Some of the important contributing factors that can be suggested are heavy grazing pressure (in both the communal and government sites), expansion of cultivation and reduced mobility of livestock due to settlement of the pastoralists in the communal land. 相似文献
998.
Assessment of Eutrophication in Estuaries: Pressure–State–Response and Nitrogen Source Apportionment 总被引:1,自引:0,他引:1
Whitall D Bricker S Ferreira J Nobre AM Simas T Silva M 《Environmental management》2007,40(4):678-690
A eutrophication assessment method was developed as part of the National Estuarine Eutrophication Assessment (NEEA) Program.
The program is designed to improve monitoring and assessment of eutrophication in the estuaries and coastal bays of the United
States with the intent to guide management plans and develop analytical and research models and tools for managers. These
tools will help guide and improve management success for estuaries and coastal resources. The assessment method, a Pressure-State-Response
approach, uses a simple model to determine Pressure and statistical criteria for indicator variables (where applicable) to
determine State. The Response determination is mostly heuristic, although research models are being developed to improve that
component. The three components are determined individually and then combined into a single rating. Application to several
systems in the European Union (E.U.), specifically in Portugal, shows that the method is transferable, and thus is useful
for development of management measures in both the Unites States and E.U. This approach identifies and quantifies the key
anthropogenic nutrient input sources to estuaries so that management measures can target inputs for maximum effect. Because
nitrogen is often the limiting nutrient in estuarine systems, examples of source identification and quantification for nitrogen
have been developed for 11 coastal watersheds on the U.S. east coast using the WATERSN model. In general, estuaries in the
Northeastern United States receive most of their nitrogen from human sewage, followed by atmospheric deposition. This is in
contrast to some watersheds in the Mid-Atlantic (Chesapeake Bay) and South Atlantic (Pamlico Sound), which receive most of
their nitrogen from agricultural runoff. Source identification is important for implementing effective management measures
that should be monitored for success using assessment methods, as described herein. For instance, these results suggest that
Northeastern estuaries would likely benefit most from improved sewage treatment, where as the Mid and South Atlantic systems
would benefit most from agricultural runoff reductions. 相似文献
999.
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
1000.
Bergquist DA 《Environmental management》2007,40(5):787-802
This article discusses environmental sustainability in aquaculture and its contribution to poverty alleviation, based on field
studies in Sri Lanka and the Philippines. The aquaculture practices studied are the monoculture of the black tiger prawn (Penneaus monodon) and milkfish (Chanos chanos) and the polyculture of the two species together with the mud crab (Scylla serrata). Factors affecting economic viability, social equity and environmental impacts in aquaculture are discussed and used to
illuminate local and regional differences between aquaculture in Sri Lanka and the Philippines. Findings indicate that the
most significant difference is the level of participation by local people (i.e., people originating ≤10 km away from the farm
location). In the Philippines, 84 % of the people involved in aquaculture are locals, whereas in Sri Lanka, 55% are outsiders.
Whether differences between the two areas can be explained by analyzing regional conditions, which might have resulted in
different aquaculture practices, is discussed. In Sri Lanka, semi-intensive shrimp monoculture is currently the most common
practice, whereas in the Philippines, extensive shrimp/fish polyculture is more common. Previous studies, as well as fieldwork,
indicate that extensive culture practices reduce environmental impacts and benefit local people more. Sustainability in aquaculture
is, however, also dependent on the extent of mangrove conversion into ponds. As such, extensive and locally owned farms do
not necessarily result in an all but sustainable situation. Keeping this in mind, it is discussed if extensive polyculture
practices might result in a more sustainable aquaculture, both environmentally and socioeconomically. 相似文献