Ecosystem Health最新文献

ABSTRACT

As with all of the world’s ecosystems, the Arctic ecosystem is challenged by anthropogenic inputs. As a result of their global vision of the ecosystem in which they live, the Inuit community is concerned with the fact that traditional food may not be edible due to pollution. As part of a broader ecosystem health research program examining the biological, economic, and cultural impacts of environmental contamination in the Arctic, the aim of our project was to assess Arctic ecosystem health by the tentative bridging of scientific and traditional knowledge. Specifically, the goal was to verify a possible relationship between Inuit perception of the health of their ecosystem and scientific assessment of deformities, pollutant levels, and parasites in Arctic char, an important food source for the Inuit. In order to do this, it was necessary to take into account Inuit knowledge of contamination and perceived effects on human and ichtyofauna health.

Two fish sampling sites were chosen in Ungava Bay, Nunavik, (northern Québec, Canada) and field sampling took place in August 1994 during the upstream migration of Arctic char. While large amounts of parasites were observed, there were no evident signs of fish health alteration such as deformities or very low condition factors despite the common observation by Inuit that deformities were more abundant than in the past. Although the hypothesis that a possible increase in parasitism in fish due to anthropogenic pollutants could be neither proved nor completely disproved (in particular because of a lack of unhealthy fish), the research process has still proved to be useful; namely, to reassure stakeholders about the quality of the fish stocks studied, to enhance dialogues between researchers and the communities involved in the project, to provide an opportunity for regional stakeholders to guide locally relevant research, and to provide researchers with some understanding of the differences between risks perceived by the general population and dangers identified by the experts.

ABSTRACT The health of human populations requires a wide variety of chemical and physical supports from their associated ecosystems, as well as from the global ecosystem. Ecosystems can be “ecologically engineered” to improve the efficiency of that service, particularly when ecosystem health fails due to human overloads. Less well recognized is an entirely different dimension of ecosystem support of human populations; namely the pharmacological value of ecosystem biodiversity. Natural product chemistries are an extremely important resource in the ever-expanding human battle with health degrading microbes.

Coral reefs are the most diverse ecosystems in the sea and have the highest density of biodiversity globally. High diversity density gives rise to intense species competition and the subsequent organism capability to construct exotic defensive and offensive chemicals, many with pharmacological value. Coral reefs are being rapidly degraded, anthropogenically, both locally and globally. It is estimated that less than 10% of reef biodiversity is currently known and only a small fraction of that percent has been tested for “active compounds”. Many species extinctions are likely in the coming decades, and badly needed pharmacological potential will subsequently be lost.

Sophisticated coral reef and reef organism culturing capability is now available that would allow the prospecting of reefs, the efficient analysis of organisms and eventually the mass culturing of those organisms for their secondary compounds without ecosystem damage. The economic value of this pharmaceutical potential needs to be directed by governments to an international crash project to conserve coral reefs and their biodiversity.

ABSTRACT We describe 4 years of an experimental rotation in ecosystem health offered to senior veterinary students in Canada. Faculty from the four Canadian veterinary colleges collaborated in offering the rotation once annually at one of the colleges. The first rotation was held in Guelph, Ontario, in 1993, followed in successive years by rotations at Saskatoon, Saskatchewan, Saint-Hyacinthe, Québec, and Charlottetown, Prince Edward Island. The rotation is a predominantly field-based experience that allows students to work with veterinary and other role models who are actively engaged in clinical research related to ecosystem health. Five specific field studies that worked particularly well during the rotations are presented. These studies involved investigating mortality in wildlife due to botulism, designing an environmental surveillance system around herds of beef cattle, using belugas to evaluate the health of the St. Lawrence River, dealing with competition for water use by aquaculture and agriculture, and exploring the role of veterinarians during major coastal oil spills. The experience has resulted in our developing the subject matter, field examples, teaching approach, and confidence necessary to make ecosystem health the focus of a productive clinical rotation for senior year veterinary students.

ABSTRACT Below many rivers and extending laterally beneath their banks lies a zone of saturated sediments—the hyporheic zone. This region is the site of dynamic exchanges of water and materials between the groundwater below, lateral alluvial aquifers, and the river flowing above. In this centrally located ecosystem component, the actions of the microbial biofilms coating the sediments are considered to act like a biological filter, enhancing water quality during the exchange process. However, the hyporheic zones in many rivers are threatened by siltation, toxicants and increasing acidity, physical extraction for gravel, or altered groundwater inputs through pumping. Current protocols to assess river health do not explicitly consider that of the hyporheic zone, despite its central role in many rivers. This oversight is due largely to the relative infancy of the discipline of hyporheic research, limited communication to river managers by ecologists, and technical difficulties in sampling the hyporheic zone. Ecosystem health assessments in rivers with potentially important hyporheic zones could include measurements of the extent of hydrological exchange between the river and the hyporheic zone at a range of scales, the rates of some key interstitial chemical processes, and perhaps the biodiversity of hyporheic invertebrates. In Australia, the potential of some of these measurements is being investigated, especially in relation to assessing the health of “groundwater-dependent ecosystems.”

ABSTRACT There is a growing recognition of the importance of transboundary shared natural resources. However, with limited resources, international policymakers need to be able to prioritize regions before allocating resources and addressing transboundary problems. River basins are perhaps the most natural transboundary division and, as such, provide an ecological framework for environmental assessments. The health of watersheds that are divided by political boundaries are at particular risk due to differential land management practices within each watershed. In Africa, more than any other continent, over 60% of the geographical area is a transboundary watershed. In this article, a comparative study of the five major basins in Africa—the Congo, Chad, Nile, Niger, and Zambezi—has been carried out using consistent geospatial data sets at 1-km resolution. Population, land cover type, and protected areas were used to assess the current status, characteristic differences, and impending pressure on river basin resources for each watershed. In addition, a focused study within the Nile River basin is used to compare the particular differences between countries.

ABSTRACT The Australian Government has made a commitment to a National Land and Water Resources Audit (Audit) to provide data, analysis, and appraisal of natural resource management and to facilitate improved decision making at a range of scales. One of the themes within the Audit is ecosystem health. This article describes the goals of the Audit with respect to ecosystem health and provides examples of how these goals are being realized in terms of projects. Six projects within the ecosystem health theme of the Audit are described. Benefits of the ecosystem health paradigm have been recognized by the Audit in comparison to previous natural resource assessment methods that tended to focus on single components of ecosystems through the use of environmental quality indicators and often failed to make distinctions and linkages between ecosystem types. A “catchment to estuary” concept which identifies the linkages between landscape, catchment, waterway, and estuarine condition is providing the rationale behind the process-based integration of natural resource data sets which form the basis of methods being developed by the Audit. This depends upon the identification of key ecosystem process drivers and a range of attributes by which they may be measured at appropriate scales. The Audit's aim is to develop purpose-driven multiattribute assessment frameworks that can incorporate a range of available natural resource information along with social and economic data to provide a measure of distance of ecosystems from some desired state. The contributions of other Audit theme projects to such assessments and the final integrated reporting requirements of the Audit across disciplinary themes is described. Perceived benefits of the ecosystem health approach to natural resource assessment and tests of effectiveness that may be used by the Audit are also discussed.