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131.
In 1788 Humphrey Repton made his important decision to carry on in the Brown tradition, and the well established Eighteenth Century English Landscape School continued in Europe for another thirty years. (Stroud: 1962) Also, in that same year, the British Government founded its first penal colony in New Holland, and as those unfortunate convicts and soldiers began clearing the virgin bush from the shores of Sydney Cove, so began the landscape destruction which has haunted Australia to the present time.  相似文献   
132.
Habitat Assessment of Non-Wadeable Rivers in Michigan   总被引:1,自引:0,他引:1  
Habitat evaluation of wadeable streams based on accepted protocols provides a rapid and widely used adjunct to biological assessment. However, little effort has been devoted to habitat evaluation in non-wadeable rivers, where it is likely that protocols will differ and field logistics will be more challenging. We developed and tested a non-wadeable habitat index (NWHI) for rivers of Michigan, where non-wadeable rivers were defined as those of order ≥5, drainage area ≥1600 km2, mainstem lengths ≥100 km, and mean annual discharge ≥15 m3/s. This identified 22 candidate rivers that ranged in length from 103 to 825 km and in drainage area from 1620 to 16,860 km2. We measured 171 individual habitat variables over 2-km reaches at 35 locations on 14 rivers during 2000–2002, where mean wetted width was found to range from 32 to 185 m and mean thalweg depth from 0.8 to 8.3 m. We used correlation and principal components analysis to reduce the number of variables, and examined the spatial pattern of retained variables to exclude any that appeared to reflect spatial location rather than reach condition, resulting in 12 variables to be considered in the habitat index. The proposed NWHI included seven variables: riparian width, large woody debris, aquatic vegetation, bottom deposition, bank stability, thalweg substrate, and off-channel habitat. These variables were included because of their statistical association with independently derived measures of human disturbance in the riparian zone and the catchment, and because they are considered important in other habitat protocols or to the ecology of large rivers. Five variables were excluded because they were primarily related to river size rather than anthropogenic disturbance. This index correlated strongly with indices of disturbance based on the riparian (adjusted R2 = 0.62) and the catchment (adjusted R2 = 0.50), and distinguished the 35 river reaches into the categories of poor (2), fair (19), good (13), and excellent (1). Habitat variables retained in the NWHI differ from several used in wadeable streams, and place greater emphasis on known characteristic features of larger rivers.  相似文献   
133.
ABSTRACT: In the last decade, watershed groups (WG) established through government initiatives have become an important part of the natural resource management landscape in developed economies. In this paper, the authors reflect upon their research and experience with Landcare in Victoria, and to a lesser extent with Watershed Councils in Oregon, to identify the principles that appear fundamental to sustaining effective WG. In the first instance, these groups must be established at a local scale using social as well as biophysical boundaries. It is also critical that WG are embedded within a supportive institutional framework that identifies realistic roles for private landowners, local organizations such as WG, and regional planning bodies. Without broad stakeholder representation, the perceived benefits of participation are quickly forfeited. It is simply unrealistic to expect an effective network of WG to be sustained without substantial investment by government to provide for program management, group coordination, and cost sharing for on‐ground work. There must also be the commitment and skills within a program to establish processes that build trust and competency amongst citizens and agencies. These principles should also provide a foundation for the critical evaluation of WG programs.  相似文献   
134.
Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] shoots from mature trees were collected from two sites of contrasting soil pH: the Glendon campus of York University in Toronto, Canada (pH 6.7 at 40 cm) designated Can.; and Breuil Forest, Morvan, France (pH 4 to 4.5) designated Fr.. Needles were removed from the shoots, frozen in liquid nitrogen, and kept in a cryo-biological storage system prior to X-ray microanalysis on the cold stage (−170°C) of a cryo-SEM. Four elements detected, potassium, phosphorus, sulphur and chlorine, were ubiquitous in the needle tissues from both sites. Manganese was infrequently found in needle tissues from the Fr. site. Calcium was localized most heavily in the outer tangential wall of the hypodermis and also in the epidermal walls. Silicon (Si) concentrations were higher in the Fr. site than in the Can. site. The epidermis, hypodermis and mesophyll of needles from the Fr. site exhibited the highest Si content, with greater amounts in the tip and middle of the needle than in the base. Aluminium was distributed fairly evenly throughout the tissues, and there were few major sites of concentration.  相似文献   
135.
Multifunctional rural landscapes are often characterised by contrasting values, land uses and land management practices of rural property owners. It seems these trends are, in part, an expression of rural landholder's identification as farmers. Existing typologies of rural landholders seldom take into account occupational identity. Research discussed in this paper addresses that gap. The objective was to apply the collective occupational identity construct to address the challenges of profiling rural landholders and test its effectiveness at distinguishing between different types of landholders. A 12-item scale was used to explore the extent rural landholders in south-eastern Australia held an agricultural producer identity. Cluster analysis resulted in the creation of four clusters of rural landholders with distinctive characteristics, suggesting the approach can provide researchers with a theoretically sound construct and practitioners with a useful tool as they attempt to better understand and engage rural landholders in sustainable agriculture.  相似文献   
136.
Sulfonylurea herbicides are applied at relatively low rates (3 to 40 g ha(-1)) to control weeds in a variety of crops across the Canadian prairies. Because of their high phytotoxicity and the likelihood of their transport in surface runoff, there is concern about their possible impact to aquatic ecosystems. Little is known, however, about their persistence and behavior in aquatic ecosystems. To assess persistence in aquatic ecosystems, three prairie farm dugouts (ponds) were fortified with either thifensulfuron-methyl {methyl 3-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]-2-thiophenecarboxylate}, ethametsulfuron-methyl {methyl 2-[[[[[4-ethoxy-6-(methylamino)-1,3,5-triazin-2-yl]amino]carbonyl]amino]sulfonyl]benzoate} or metsulfuron-methyl {methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazinyl)amino]carbonyl]amino]sulfonyl]benzoate}. The decreasing order of persistence of environmentally relevant concentrations (1 to 4.6 microg L(-1)) of these herbicides in dugout water over the June to October period was metsulfuron-methyl>ethametsulfuron-methyl>thifensulfuron-methyl. The corresponding dissipation half-lives (DT(50)) of 84, 30, and 16 d, respectively, are in the same relative order as the recropping intervals for these herbicides. Thifensulfuron-methyl showed a biphasic dissipation with slower dissipation during the winter months. In contrast, the dissipation of metsulfuron-methyl, the sulfonylurea herbicide with the longest DT(50), was somewhat enhanced under winter conditions. One of the major routes of sulfonylurea herbicide dissipation was removal from the water column when dugout water was lost during hydrological discharge. The relatively long persistence of these herbicides in water indicates that partitioning into sediments was minimal, the sulfonylurea and methyl ester linkages in these compounds were resistant to hydrolysis in weakly alkaline waters, and that microbial and photolytic degradation in dugout waters were slow.  相似文献   
137.
Landcare is an Australian success story and an important example of the potential of state-sponsored community participation. An important trend encouraged by the lead agencies is for Landcare groups to be linked through so-called networks. Linking together may appeal to groups as a way of increasing their capacity to compete for scarce resources and enhance their impact on agencies, regional catchment committees and government. Network formation is also driven by government and agency demands for efficiency, accountability and effective regional planning. In this paper the authors draw on their 1997 study of the Ovens Valley Landcare Network in Victoria. This research suggested networks are important local organisations and enhance the impact of groups by improving inter-group communication and 'pulling down' resources. Network processes also contributed to robust, productive, agency-community partnerships and suggested participation can increase community influence on decision making and be compatible with adaptive management.  相似文献   
138.
Cultural heritage sites form an unrenewable asset that is threatened by natural disasters. Given the high bushfire risk, mandatory Bush Fire Risk Management Plans have been drawn up throughout New South Wales, Australia. We compared their mandatory provisions for the protection of heritage assets with an 'Ideal Heritage Disaster Plan', containing a series of non-negotiable elements. The examined plans fell well short of the ideal. Preparedness Plans generally lacked a discussion of suppression techniques (for historic heritage), prevention, prescribed drills and communication procedures. None of the Response Plans or Recovery Plans contained any of the required core elements, such as rapid suppression techniques and stabilisation procedures. Where aspects were covered, they were addressed in an inadequate level of detail. The overall quality of the cultural heritage components of the plans is judged to be poor. Suggestions are made on how to improve the situation if heritage assets are to have a future following bushfire events.  相似文献   
139.
BACKGROUND: Call centres (CCs) are among the most rapidly growing forms of workplaces in Sweden. The purpose of the study was to describe and compare working conditions between operators at internal and external CC companies and work tasks of different complexity. METHOD: A questionnaire was answered by 1183 operators, 848 women and 335 men, from 28 different CCs. The questionnaire covered background factors, employment, working hours and remuneration, call logging and monitoring, duties, computer work and workplace design during the previous month. RESULTS: Operators at external companies and operators with low-complexity work tasks were younger, more often employed by the hour and worked on a varying roster. They spent longer time on customer calls and had less varied tasks. Additional remuneration, call logging and monitoring were more common at external companies and among operators with low-complexity work tasks. CONCLUSION: The working conditions varied between internal and external CCs. There was also a variation in working conditions between work tasks of different complexity. There were aspects of supervision style and organization of work at CCs, especially at external ones and those with low-complexity tasks that could introduce stress and lack of well being among the staff.  相似文献   
140.
OBJECTIVE: to determine access to vehicles, vehicle ownership and its correlates, and types of vehicles driven by teenagers during their first year of licensure. METHODS: About 3,500 Connecticut teenagers and their parents recruited at DMV offices participated in a study aimed at persuading parents to impose and maintain driving restrictions on their sons and daughters. Telephone interviews with teens and parents, which included questions on vehicles driven, were conducted upon licensure and at intervals throughout the year. RESULTS: The majority of both male and female teens owned vehicles immediately upon licensure. Family income and number of vehicles in the family were associated with early ownership. A year later 74% owned vehicles. Small cars, which provide inferior crash protection, were the most popular vehicle; the percent driving small cars increased from 36% to 42% over the year. About 25% were driving SUVs, pickups, or sports cars, which may increase crash risk for young beginners. One year after licensure, only 35% of teens were driving midsize or large passenger cars, the types of vehicles recommended for them, and about one-third of these vehicles were 10 or more years old. Owners were more likely than non-owners to drive older and smaller vehicles, to drive more miles, do more risky driving, and to have more traffic violations and crashes. DISCUSSION: Many teenagers in Connecticut were driving vehicles that rank low in crash protection or may increase crash risk. Attention to the young driver problem has been focused primarily on managing driving risks through graduated licensing systems. More attention needs to be given to the vehicles teens drive, and how decisions about vehicle type and ownership are made. Parents exert control over what vehicles their sons and daughters drive, and may benefit from information on how to make choices that better balance cost, safety, and other factors that go into these decisions.  相似文献   
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