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971.
Managing Urban Trees and Their Soil Envelopes in a Contiguously Developed City Environment 总被引:7,自引:0,他引:7
Jim CY 《Environmental management》2001,28(6):819-832
Urban Hong Kong is covered by high building, road, and population densities. Its urban morphology is inherently not conducive
to extensive or high-grade greening. Recent renewal of old areas has squeezed out some limited interstitial plantable space,
although in new development areas modest spaces have been earmarked for greenery. The study aims at evaluating the major constraints
to urban trees and their companion urban soil envelopes and at providing specific recommendations to improve tree management
in the city. The analysis covers the above-ground confinements that dampen tree performance, the less tangible but rather
difficult institutional restrictions that impose a somewhat unnecessary lid on tree planting, the multiplicity of players
and stakeholders involved in urban-tree management that militates against coordination and cooperation, the widespread occupation
of underground space by utility lines often to the exclusion of trees, and the extremely poor quality of urban soils that
are often used without amelioration to support tree growth. The management recommendations furnish practical suggestions and
hints to improve the short- and long-term welfare of trees in terms of quality, quantity, and spatial distribution. The conclusion
enumerates some concrete measures for consideration by decision-makers to upgrade the city's greenery to close the gap between
science and policy. 相似文献
972.
The Cache River of southernmost Illinois is used as a case study for developing and demonstrating an approach to quantitatively
link (1) national agricultural policy and global agricultural markets, (2) landowner's decisions on land use, (3) spatial
patterns of land use at a watershed scale, and (4) hydrologic impacts, thus providing a basis to predict, under a certain
set of circumstances, the environmental consequences of economic and political decisions made at larger spatial scales. The
heart of the analysis is an estimation, using logistic regression, of the affect of crop prices and Conservation Reserve Program
(CRP) rental rates on farmland owner's decisions whether to reenroll in the CRP or return to crop production. This analysis
shows that reasonable ranges for crop prices (80%–150% of 1985–1995 values) and CRP rental rates (0–125% of 1985–1995 rates)
result in a range of 3%–92% of CRP lands being returned to crop production, with crop prices having a slightly greater effect
than CRP rental rates. Four crop price/CRP rental rate scenarios are used to display resulting land-use patterns, and their
effect on sediment loads, a critical environmental quality parameter in this case, using the agricultural non point source
(AGNPS) model. These scenarios demonstrate the importance of spatial pattern of land uses on hydrological and ecological processes
within watersheds. The approach developed can be adapted for use by local governments and watershed associations whose goals
are to improve watershed resources and environmental quality. 相似文献
973.
Design and Performance of a Channel Reconstruction Project in a Coastal California Gravel-Bed Stream 总被引:1,自引:0,他引:1
A 0.9 km-reach of Uvas Creek, California, was reconstructed as a sinuous, meandering channel in November 1995. In February 1996, this new channel washed out. We reviewed project documents to determine the basis for the project design and conducted our own historical geomorphological study to understand the processes operating in the catchment and project reach. The project was designed using a popular stream classification system, based on which the designers assumed that a "C4" channel (a meandering gravel-bed channel) would be stable at the site. Our historical geomorphological analysis showed that the reach had been braided historically, typical of streams draining the Franciscan Formation in the California Coast Ranges, with episodic flows and high sand and gravel transport. After the project washed out, Uvas Creek reestablished an irregular, braided sand-and-gravel channel, although the channel here was narrower than it had been historically, probably due to such factors as incision caused by gravel mining. Our study casts doubt on several assumptions common in many stream restoration projects: that channel stability is always an appropriate goal; that channel forms are determined by flows with return periods of about 1.5 years; that a channel classification system is an easy, appropriate basis for channel design; and that a new channel form can be imposed without addressing the processes that determine channel form. 相似文献
974.
Optimum natural resource management and biodiversity conservation are desirable goals. These, however, often exclude each
other, since maximum economic benefits have promoted drastic reductions in biodiversity throughout the world. This dilemma
confronts local stakeholders, who usually go for maximizing economic inputs, whereas other social (e.g., academic) sectors
are favor conservation practices. In this paper we describe the way two scientific approaches—landscape and participatory
research—were used to develop sound and durable land use scenarios. These two approaches included expert knowledge of both
social and environmental conditions in indigenous communities. Our major emphasis was given to detect spatially explicit land
use scenarios and capacity building in order to construct a decision support system operated by stakeholders of the Comunidad
Indigena de Nuevo San Juan Parangaricutiro in Mexico. The system for decision-making was fed with data from inventories of
both abiotic and biotic biodiversity components. All research, implementation, and monitoring activities were conducted in
close collaboration with members of the indigenous community. As a major result we obtained a number of forest alternative
uses that favor emerging markets and make this indigenous community less dependent on a single market. Furthermore, skilled
members of the community are now running the automated system for decision-making. In conclusion, our results were better
expressed as products with direct benefits in local livelihoods rather than pure academic outputs. 相似文献
975.
Environmental Policy Implementation in Rural China: A Case Study of Yuhang, Zhejiang 总被引:4,自引:0,他引:4
The rapid growth of rural enterprises has transformed the Chinese countryside. Although rural industrialisation has resulted
in increased financial well-being, it has also contributed to decreased environmental quality. While China has strong environmental
protection laws, this paper will demonstrate that they are not being effectively implemented in a rural region in Zhejiang
Province. This is due to a number of social, political, and economic barriers that prevent agencies from effectively enforcing
environmental policies and regulatory mechanisms.
This paper investigates the implementation of China's environmental policies through a case study in Yuhang County, Zhejiang
Province. It demonstrates that the implementation of environmental impact assessment, discharge fees, and limited time treatment
is limited by inadequate technology, low finances, limited human resources, poor public environmental awareness, faulty data,
inferior agency reports, organizational conflict, relations based on guanxi, and low discharge fee prices. 相似文献
976.
Linnell JD Andersen R Kvam T Andrén H Liberg O Odden J Moa PF 《Environmental management》2001,27(6):869-879
Annual and seasonal home ranges were calculated for 47 Eurasian lynx in four Scandinavian study sites (two in Sweden and two
in Norway). The observed home ranges were the largest reported for the species, with study site averages ranging from 600
to 1400 km2 for resident males and from 300 to 800 km2 for resident females. When home range sizes were compared to the size of protected areas (national parks and nature reserves)
in Scandinavia, it was concluded that very few protected areas contained sufficient forest to provide space for more than
a few individuals. As a direct consequence of this, most lynx need to be conserved in the multiuse seminatural forest habitats
that cover large areas in Scandinavia. This conservation strategy leads to a number of conflicts with some land uses (sheep
and semidomestic reindeer herding, and roe deer hunters), but not all (forestry and moose harvest). Accordingly research must
be aimed at understanding the ecology of these conflicts, and finding solutions. 相似文献
977.
Ecological Compensation in Dutch Highway Planning 总被引:13,自引:0,他引:13
The ecological compensation principle was introduced by the Dutch government in 1993. This principle is designed to enhance
the input of nature conservation interests in decision-making on large-scale development projects and to counterbalance the
ecological impacts of such developments when implemented. This article evaluates the application of the Dutch compensation
principle in highway planning. Six current highway projects reveal consistent implementation of this principle, although provincial
policies on compensation and a national method for identifying compensation measures are still under development. As the planning
process has not yet been completed for all the projects, no general conclusions can be drawn on the impact of the compensation
principle on highway decision-making. Nevertheless, several examples show that the principle stimulates project initiators
to develop alternative routes or route sections in order to avoid or reduce ecological impacts and the need for coherent compensation
measures. If the compensation principle is to be properly implemented in the context of highway planning, particular attention
should be paid to the following aspects: (1) sequential assessment of overall project legitimacy and the necessity of intersecting
protected areas and compensation measures, (2) the initiator's attempts to avoid and mitigate ecological impacts in developing
alternative routes prior to compensation for impacts, and (3) the role of uncertain ecological impacts in identifying compensation
measures, especially those concerning habitat isolation. 相似文献
978.
Proactive Management of Air Quality 总被引:1,自引:0,他引:1
Traditional air resource management systems have difficulty in addressing global issues, sustainable development, direct citizen
participation, and integration with broad economic interests. As reactive management systems, they tend to be compliance-driven,
static, and rigid. In contrast, proactive management systems are principle-driven, innovative, and flexible. Bridge scientists
play a key role in supporting the transformation of raw data into wise action. Decision-makers need to integrate social values
with knowledge about emissions, atmospheric processes, and potential environmental effects using the primary tools of measurements,
monitoring, and modeling. The Alberta Clean Air Strategic Alliance, a unique partnership of governments, industry, and public
interest groups formed in 1994, operates a comprehensive air management system that is capable of addressing air issues of
greater complexity and uncertainty. Its success is measured by the satisfaction of its diverse stakeholders and by the number
and scope of its initiatives. 相似文献
979.
This paper explores the positive aspects of collaboration in natural resources. Its purpose was to investigate participants'
overall attitudes about keys to successful collaboration. The sample for the study consisted of 671 participants involved
in 30 collaborative initiatives (CI) with the Forest Service. Using a mailed questionnaire, this study profiled the collaborative
initiatives investigating purpose, problems addressed, groups involved, and years in existence. Respondents were queried on
their overall perspectives on keys to successful collaboration. A total of more than 300 comments was collected from respondents
and six categories emerged: development, information exchange, organizational support, personal communication, relationships/team
building, and accomplishments. Continued research will need to explore the short- and long-term impacts of collaboration in
natural resources. 相似文献
980.
The objective of this research is to develop a desirable type III environmental declaration format for the industrial consumer.
A total of five different scenarios were chosen for the presentation of life-cycle assessment results in a format that meets
the requirements of a type III environmental declaration. Life-cycle assessment of an electronic component was performed for
this purpose. Environmentally significant impact categories and input/output items of a product system derived from the life-cycle
assessment are presented in this format. Presenting these information concisely in a standardized format would accelerate
the communication of environmental aspects of materials and components in a product supply chain. Thus the type III environmental
declaration can be a useful instrument for the manufacturing of an ecoproduct. 相似文献