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1.
The possible effects of landscape structure on starling roost distribution were investigated in western France using GIS analysis at different radii (2, 4, 8 and 10 km). Composition (11 land use classes) and configuration (patch size, diversity index) of the landscapes surrounding 97 roost sites used by starlings from 1981 to 2002 and surrounding 50 random points not used as roost sites were compared. Significant results suggested that starling roosts were established preferentially in the centre of an agricultural landscape where large units of pastures and arable land predominated and where natural areas were lacking both in large patches (forests or wetland classes) and in small patches such as woods in the mixed land class. A varied farmland landscape with natural areas and small patches should be promoted to limit the starling damage in wintering regions and also to favour their reproduction in regions where it has declined. 相似文献
2.
This study integrated aerial photographs from 1952, 1981, and 1998, and a satellite image from 2000 with oral histories and
socioeconomic surveys to assess changes in forest and land cover in Ang Nhai village, Laos. The study documents the history
of resource use and changes in household access to resources in the village. Three distinctive trends were observed in terms
of forest and land cover—forest degradation, deforestation, and regeneration. Project results suggest that land and forest
cover change dynamically under different circumstances. The case study also points out that integration into the market economy
can induce intensification of unused lowland areas, while removing pressures from upland areas previously used for supplementing
agricultural production. In addition, the creation of a national reserve forest to restrict local access and forest use was
an ineffective tool for regulating encroachment and logging activities. 相似文献
3.
Multi-criteria analysis via the VIKOR method for prioritizing land-use restraint strategies in the Tseng-Wen reservoir watershed 总被引:2,自引:0,他引:2
It is important to adopt proper water and soil conservation and land-use planning in a watershed for lowering adverse impacts on reservoir water quality. Although reservoir watersheds occupy a large amount of land in Taiwan, high population density has exerted development pressures on such land. Therefore, the priority ranking of land-use restrictions for the subdivisions with different degrees of environmental vulnerability is necessary in watershed management. Since there are several criteria for evaluating the potential environmental impact from the subdivisions, multi-criteria analysis was applied as a technique for solving these problems in this study. The VIKOR method was applied to determine the best feasible solution according to the selected criteria, including geographical and meteorological factors. The objective of this study was to establish the priority ranking of land-use restrictions in the Tseng-Wen reservoir wastershed in southern Taiwan. The results show that subdivisions close to the outlet or reservoir area should have the priority of land-use restrictions. 相似文献
4.
Understanding how hydraulic factors control alluvial river meander migration can help resource managers evaluate the long-term
effects of floodplain management and bank stabilization measures. Using a numerical model based on the mechanics of flow and
sediment transport in curved river channels, we predict 50 years of channel migration and suggest the planning and ecological
implications of that migration for a 6.4-km reach (river miles 218–222) of the Sacramento River near the Woodson Bridge State
Recreation Area, California, USA.
Using four different channel management scenarios, our channel migration simulations suggest that: (1) channel stabilization
alters the future channel planform locally and downstream from the stabilization; (2) rock revetment currently on the bank
upstream from the Woodson Bridge recreation area causes more erosion of the channel bank at the recreation area than if the
revetment were not present; (3) relocating the channel to the west and allowing subsequent unconstrained river migration relieves
the erosion pressure in the Woodson Bridge area; (4) the subsequent migration reworks (erodes along one river bank and replaces
new floodplain along the other) 26.5 ha of land; and (5) the river will rework between 8.5 and 48.5 ha of land in the study
reach (over the course of 50 years), depending on the bank stabilization plan used. The reworking of floodplain lands is an
important riparian ecosystem function that maintains habitat heterogeneity, an essential factor for the long-term survival
of several threatened and endangered animal species in the Sacramento River area. 相似文献
5.
Modeling the spatial dynamics of regional land use: the CLUE-S model 总被引:95,自引:3,他引:92
Verburg PH Soepboer W Veldkamp A Limpiada R Espaldon V Mastura SS 《Environmental management》2002,30(3):391-405
Land-use change models are important tools for integrated environmental management. Through scenario analysis they can help
to identify near-future critical locations in the face of environmental change. A dynamic, spatially explicit, land-use change
model is presented for the regional scale: CLUE-S. The model is specifically developed for the analysis of land use in small
regions (e.g., a watershed or province) at a fine spatial resolution. The model structure is based on systems theory to allow
the integrated analysis of land-use change in relation to socio-economic and biophysical driving factors. The model explicitly
addresses the hierarchical organization of land use systems, spatial connectivity between locations and stability. Stability
is incorporated by a set of variables that define the relative elasticity of the actual land-use type to conversion. The user
can specify these settings based on expert knowledge or survey data. Two applications of the model in the Philippines and
Malaysia are used to illustrate the functioning of the model and its validation. 相似文献
6.
Since the end of the 1970s, the southern European countries have shown an exceptional reduction in fertility rate. From the
highest levels among the developed nations, these countries dropped beneath the substitution rate level: in Greece there is
an average of about 1.5 children per woman, and Italy (starting three to four years ago), with 1.3 children per woman, is
now the country with the lowest fecundity rate in the world. Land-use planning in southern European small islands therefore
requires substantial revision. In the areas where western civilization began, which are highly populated and have a long history,
cultural and ethnic aspects of tradition are fundamental to environmental management and to the defense of historical heritage.
They also place a strong value on sustaining tourism, the most relevant economic activity, that allows them to survive and
maintain a high welfare level. For some decades they have had populations with a marked presence of young people and high
emigration rates, but now they are fast becoming dominated by the elderly and must prepare for a period of fast reduction
in youth of the workforce, while the peripheral areas of Asia and Africa are entering a sudden demographic growth phase.
The demographic structure has also been deeply altered both by previous migrations and by random variations, as usually happens
in all small communities. Social services for younger and older people have had to be adapted rapidly, reorganizing high-school
management, hospital and health-care structures, in-house assistance, and so on. There is a need to rethink the job market
and favor the immigration of highly specialized workers, which is a necessity for technical evolution. Sustainable development
is constrained nowadays not only by the scarcity of natural resources, but also by the quality and quantity of human resources.
Proper policies for population and land-use planning are highly correlated factors; they have to be considered with respect
of these new, rapid demographic changes. 相似文献
7.
It is a common experience that public administrations tend to shy away from the explicit acknowledgment of quantitative risk
levels. Faced with extreme concentrations of population and of industrial activities, including LPG and liquid chlorine storage,
within a very small land area, Hong Kong has faced up to the issue of major man-made hazards by “thinking the unthinkable”
and adopting explicit risk guidelines. This article describes how these guidelines were developed and the arguments that led
to their adoption. It is emphasized that the risk guidelines are not rigid standards but simply a method of focusing decision
making and ensuring that any decision to contravene the guidelines is taken at an appropriately senior level in the administration.
The way in which the guidelines have been incorporated intimately into the planning and decision-making process is described
and details are given on how this has led to the implementation of a variety of measures that have greatly reduced both societal
and individual risk from certain types of chemical storage and chemical processing installations in Hong Kong.
The opinions in this paper represent the views of the authors and not necessarily those of the Hong Kong Government. 相似文献
8.
Chen-Tung?Arthur?ChenEmail author James?T.?Liu Ben-Jei?Tsuang 《Regional Environmental Change》2004,4(1):39-48
Rapid economic and industrial development in Taiwan over the past five decades has elevated the islands standing and earned it a place in the group known as the Four Small Dragons of Asia. Such growth, however, has been at the expense of the environment. There are currently nearly 23 million people juggling for space on the small island of 35,873 km2. Aggravating the matter further, the central mountain ranges and hills take up 73.6% of the land area with some 156 peaks surpassing 3,000 m. As a result, most people live in coastal plains which amount to only 9,490 km2. Pressure to move people inland has led to road construction and deforestation, both of which have contributed to an already high denudation rate of topsoil. As a consequence of this, thirteen rivers in Taiwan are now ranked among the top 20 worldwide in terms of sediment yield. Aside from this, the frequency of both floods and droughts increased prior to 1990, perhaps because of deforestation and global warming. Fortunately, the new conservation-orientated forest management policy of 1991 has alleviated the problem, somewhat, and the occurrence of floods and droughts has since decreased. The problem of water shortage, however, has worsened because of the warming trend in atmospheric temperature. Damming may ameliorate the water shortage problem but may affect the shoreline stability, as well as the ecology and water quality in the estuaries. Furthermore, these detrimental effects may go far beyond the estuaries, and even fisheries on the continental shelves may be affected. 相似文献
9.
This paper explores the concept of homegardens and their potential functions as strategic elements in land-use planning, and adaptation and mitigation to climate change in Sri Lanka. The ancient and locally adapted agroforestry system of homegardens is presently estimated to occupy nearly 15 % of the land area in Sri Lanka and is described in the scientific literature to offer several ecosystem services to its users; such as climate regulation, protection against natural hazards, enhanced land productivity and biological diversity, increased crop diversity and food security for rural poor and hence reduced vulnerability to climate change. Our results, based on a limited sample size, indicate that the homegardens also store significant amount of carbon, with above ground biomass carbon stocks in dry zone homegardens (n = 8) ranging from 10 to 55 megagrams of carbon per hectare (Mg C ha−1) with a mean value of 35 Mg C ha−1, whereas carbon stocks in wet zone homegardens (n = 4) range from 48 to 145 Mg C ha−1 with a mean value of 87 Mg C ha−1. This implies that homegardens may contain a significant fraction of the total above ground biomass carbon stock in the terrestrial system in Sri Lanka, and from our estimates its share has increased from almost one-sixth in 1992 to nearly one-fifth in 2010. In the light of current discussions on reducing emissions from deforestation and forest degradation (REDD+), the concept of homegardens in Sri Lanka provides interesting aspects to the debate and future research in terms of forest definitions, setting reference levels, and general sustainability. 相似文献
10.
We present a new mathematical programming framework that is adaptable to a variety of spatially explicit landscape problems
in environmental investment, conservation, and land-use planning, transport planning, and agriculture. As part of capturing
spatial interdependencies, the framework considers decision variables at two levels, finely spaced grid cells and landholdings.
We applied the framework to an environmental investment problem using objective functions representing biodiversity and carbon
sequestration. We also tested the model to optimize the path of a road through part of the landscape. Using the Nambucca case
study in eastern Australia, we applied a hybrid greedy randomised adaptive search procedure (GRASP) to find solutions to the
model. 相似文献