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排序方式: 共有264条查询结果,搜索用时 15 毫秒
41.
Diets of calanoid copepods on the West Florida continental shelf: Relationships between food concentration,food composition and feeding activity 总被引:3,自引:0,他引:3
Bottle incubations were conducted in March, July/August and October 1992. to measure the daily rations (R) and objectively characterize the diets of the calanoid copepodsEucalanus elongatus, Undinula vulgaris, Centropages velificatus andTemora stylifera from the west Florida continental shelf. Daily rations,R, were clustered around two, order-of-magnitude different means, 1.3 and 11.2% of body C d–1, representative of quiescent and active feeding modes, respectively. The food concentration at which the transition from quiescent to active mode occurred was influenced by food particle size. In the quiescent mode, diets were dominated by nanoplankton, whereas no food type dominated the diet in the active mode. Selective feeding, defined as a statistically significant difference between the frequency distributions of foods in the diet and environment, occurred in both quiescent and active copepods. However, what appeared to be selective feeding in quiescent copepods could be explained by processes that passively modified the distribution of the diet relative to that of the food supply. Conversely, selective feeding in active copepods apparently resulted from foraging for particles >5 m in diameter in food environments dominated by nanoplankton (<5 m). 相似文献
42.
David T. Bell Daniel J. Carter Robert E. Hetherington 《Environmental geochemistry and health》1986,8(4):99-104
Wind tunnel experiments on rehabilitation surfaces at Eneabba, Western Australia evaluated the techniques used by Associated
Minerals Consolidated Ltd. (AMC) and Allied Eneabba Ltd. (AEL) to stabilize regions being revegetated following heavy mineral
sand mining.
Newly landscaped areas proved to be the most erodible, beginning to erode at 9 m sec−1 and producing a soil flux of 10 kg m−1 min−1 at 18 m sec−1 wind speeds. Sandier, more organically-rich, surfaces in the rehabilitation areas were somewhat less erodible with losses
of only 2 kg m−1 min−1 at wind speeds of 18 m sec−1.
The mining companies use various nurse crops and top dressing mulch for surface stabilization. Rows of oats, sparse plantings
of the grass cultivar “SUDAX” (Dekalb ST6) supplied by Westfarmers Ltd. and applications of Terolas, a cold, bituminous surface
binding material supplied by Shell Co. of Australia Ltd., all proved successful in reducing wind erosion in this semi-arid
region where more than 25% of summer days experience winds greater than 8 m sec−1. 相似文献
43.
/ Public contact is a vital component of any program to manage natural resources. A well-planned public contact program uses a variety of strategies to create a sympathetic and environmentally aware public and to meet specific management-related objectives. A methodology is proposed that can be applied to planning public contact at any level, from media design for a specific project to corporate strategies for communication. The methodology integrates management-driven, client-driven and resource-driven planning to provide the connections essential to effective communication.KEY WORDS: Planning; Public contact; Interpretation; Conservation; Management 相似文献
44.
Teuschler LK Gennings C Hartley WR Carter H Thiyagarajah A Schoeny R Cubbison C 《Chemosphere》2005,58(9):1283-1291
The United States Environmental Protection Agency (USEPA) has pursued the estimation of risk of adverse health effects from exposure to chemical mixtures since the early 1980s. Methods used to calculate risk estimates of mixtures were often based on single chemical information that required assumptions of dose-addition or response-addition and did not consider possible changes in response due to interaction effects among chemicals. Full factorial designs for laboratory studies can produce interactions information, but these are expensive to perform and may not provide the information needed to evaluate specific environmentally relevant mixtures. In this research, groups of Japanese medaka (Oryzias latipes) embryos were exposed to binary mixtures of benzene and toluene as well as to each of these chemicals alone. Endpoint specific dose-response models were built for the hydrocarbon mixture under an assumption of dose-additivity, using the single chemical dose-response information on benzene and toluene. The endpoints included heart rate, heart rate progression, and lethality. Results included a synergistic response for heart rate at 72 h of development, and either additivity or antagonism for all other endpoints at 96 h of development. This work uses an established statistical method to evaluate the toxicity of an environmentally relevant mixture to ascertain whether interaction effects are occurring, thus providing additional information on toxicity. 相似文献
45.
46.
Making index insurance attractive to farmers 总被引:1,自引:0,他引:1
Anthony Patt Nicole Peterson Michael Carter Maria Velez Ulrich Hess Pablo Suarez 《Mitigation and Adaptation Strategies for Global Change》2009,14(8):737-753
There are several factors that influence whether people will want to participate in index insurance programs. A number of
these influence their attractiveness on economic grounds, including both the size and timing of the premium and potential
payouts, and the degree of risk aversion of the potential customers. Other factors make programs attractive for reasons that
are not economic, but no less valid. These have to do with the trust that people have in the insurance product and the organizations
involved in selling and managing it. Indeed, data from India, Africa, and South America show that these factors may be more
important than the economic ones in influencing demand. Index insurance pilot projects, in order to estimate demand for alternative
products, have typically involved a great deal of interaction with potential customers. It is important to recognize that
such interaction is crucial not just as a research tool, but also as a means to build understanding and trust in the products.
When scaling up from isolated pilots to operational programs, it is vital to recognize this trust building function by replicating
participation efforts in every community. In this paper, we examine the role of field games in establishing and building trust
in three important aspects of these projects for participants: trust in the insurance product, trust in the participating
organizations, and trust in their own ability to make good decisions. While games have previously been used as a way to gauge
interest in the product and to identify design features, we argue that these games are also valuable tools for constructing
these kinds of trust. 相似文献
47.
Trends in Wildlife Management and the Appropriateness of Australian University Training 总被引:1,自引:0,他引:1
Abstract: That the greatest challenges in conservation are often not technical but rather economic or sociological has been expressed for at least the last 20 years. This raises the question of whether the training offered to tomorrow's conservation practitioners prepares them sufficiently to deal with the human dimensions of conservation. We analyzed 747 papers from seven wildlife management and conservation biology journals to determine the trends in this area of conservation management between 1985 and 1995. We found that over that time the emphasis stayed on single-species issues with a science focus, but there was a marked shift toward conservation biology issues, management-oriented research, and discussion of economic and social factors relevant to management. We also examined the handbooks of 11 Australian universities to analyze the content of 439 compulsory subjects in 12 degrees that we judged could produce wildlife managers. More than 68% of subjects were from a basic science or technology discipline, 16% from resource management, and only 13% from economics, humanities, communications, or planning. Thus, many of the skills required by contemporary wildlife managers must be learned in postgraduate training or on the job. Much of the undergraduate training syllabus, in Australia at least, does not reflect trends in the practice of wildlife management today and will not provide tomorrow's managers with the range of disciplinary understanding required. We were able, however, to identify three types of undergraduate training—ecological system managers, environmental managers, and human system managers—and we found that the curricula in human-system management contained increased emphasis on socioeconomic issues relevant to management. 相似文献
48.
Cleland EE Allen JM Crimmins TM Dunne JA Pau S Travers SE Zavaleta ES Wolkovich EM 《Ecology》2012,93(8):1765-1771
Earlier spring phenology observed in many plant species in recent decades provides compelling evidence that species are already responding to the rising global temperatures associated with anthropogenic climate change. There is great variability among species, however, in their phenological sensitivity to temperature. Species that do not phenologically "track" climate change may be at a disadvantage if their growth becomes limited by missed interactions with mutualists, or a shorter growing season relative to earlier-active competitors. Here, we set out to test the hypothesis that phenological sensitivity could be used to predict species performance in a warming climate, by synthesizing results across terrestrial warming experiments. We assembled data for 57 species across 24 studies where flowering or vegetative phenology was matched with a measure of species performance. Performance metrics included biomass, percent cover, number of flowers, or individual growth. We found that species that advanced their phenology with warming also increased their performance, whereas those that did not advance tended to decline in performance with warming. This indicates that species that cannot phenologically "track" climate may be at increased risk with future climate change, and it suggests that phenological monitoring may provide an important tool for setting future conservation priorities. 相似文献
49.
A review of recent literature in the fields of operations, supply chain, and management indicates there is on-going interest in improving new product development (NPD) performance. Three-dimensional concurrent engineering (3DCE), the simultaneous design of product, process and supply chain have been proposed as a way to improve traditional NPD outcomes, such as reduced time to market, lower costs, and improved customer acceptance. There appears to be a lesser concern associated with the environmental impacts of new products. Environmentally responsible manufacturing (ERM) on new product development focuses on reduced emissions, hazardous materials elimination, and lower product weight without sacrificing functionality. This paper explores the following issue: will employing 3DCE to integrate NPD and ERM yield better benefits than the separate and uncoordinated application of environmental goals and NPD initiatives? 相似文献
50.
Approaches to Evaluating Climate Change Impacts on Species: A Guide to Initiating the Adaptation Planning Process 总被引:1,自引:1,他引:0
Assessing the impact of climate change on species and associated management objectives is a critical initial step for engaging
in the adaptation planning process. Multiple approaches are available. While all possess limitations to their application
associated with the uncertainties inherent in the data and models that inform their results, conducting and incorporating
impact assessments into the adaptation planning process at least provides some basis for making resource management decisions
that are becoming inevitable in the face of rapidly changing climate. Here we provide a non-exhaustive review of long-standing
(e.g., species distribution models) and newly developed (e.g., vulnerability indices) methods used to anticipate the response
to climate change of individual species as a guide for managers grappling with how to begin the climate change adaptation
process. We address the limitations (e.g., uncertainties in climate change projections) associated with these methods, and
other considerations for matching appropriate assessment approaches with the management questions and goals. Thorough consideration
of the objectives, scope, scale, time frame and available resources for a climate impact assessment allows for informed method
selection. With many data sets and tools available on-line, the capacity to undertake and/or benefit from existing species
impact assessments is accessible to those engaged in resource management. With some understanding of potential impacts, even
if limited, adaptation planning begins to move toward the development of management strategies and targeted actions that may
help to sustain functioning ecosystems and their associated services into the future. 相似文献