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951.
The occurrence of Tubiluchus corallicola (van der Land) in a lagoon on the East coast of Barbados, West Indies, is reported. 23 adult and 2 larval specimens were found in a sample taken from a subtidal stromatolite on which the animals presumably inhabited the algal surface layer. A comparison with data from earlier findings shows that the species is not confined to a particular type of substratum, yet morphologically it seems to be well adapted for a life in the interstitial sand habita. For the first time, living animals were observed and photographed. Their behavior and movements are briefly described and an account of morphological and histological details, as seen in squeezing preparations and photomicrographs, is presented.Supported in part by NSF Grant GB-7952 相似文献
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Thorjφrn Larssen 《Ambio-人类环境杂志》2003,32(3):244-248
20世纪的大部分时间里,由于附近的萨德伯里冶炼厂的硫排放,致使基拉尼省立公园内湖泊的酸性物质沉降一直处于较高的水平.目前,这个大型点源的硫排放量已降到上世纪60年代的10%左右.由于排放量减少,基拉尼湖的水质已发生了很大的变化,尤其是硫、铝和钙的浓度明显降低.本文在对基拉尼公园3个湖泊的酸化研究中,采用了动态酸化模型(MAGIC).这3个湖泊各自具有不同的缓冲能力和响应时间,代表了快速、中速和慢速酸化恢复的3种情况.经过对模型校正,使其与现场观测数据相匹配,并针对未来硫沉积减少的4种情况进行了酸化恢复预测.结果表明基拉尼湖的水质还有很大的改善潜力.不同湖泊的恢复时间差异很大.对于响应最慢的湖泊,在沉积量减少后,物质的组成和化学性质的稳定可能需要几十年时间. 相似文献
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Christine Schonewald-Cox Marybeth Buechner Raymond Sauvajot Bruce A. Wilcox 《Environmental management》1992,16(2):273-282
Protecting biodiversity on public lands is difficult, requiring the management of a complex array of factors. This is especially
true when the ecosystems in question are affected by, or extend onto, lands outside the boundaries of the protected area.
In this article we review recent developments in the cross-boundary management of protected natural resources, such as parks,
wildlife reserves, and designated wilderness areas.
Five ecological and 11 anthropic techniques have been suggested for use in cross-boundary management. The categories are not
mutually exclusive, but each is a distinct and representative approach, suggested by various authors from academic, managerial,
and legal professions. The ecological strategies stress the collection of basic data and documentation of trends. The anthropic
techniques stress the usefulness of cooperative guidelines and the need to develop a local constituency which supports park
goals.
However, the situation is complex and the needed strategies are often difficult to implement. Diverse park resources are influenced
by events in surrounding lands. The complexity and variability of sources, the ecological systems under protection, and the
uncertainty of the effects combine to produce situations for which there are no simple answers. The solution to coexistence
of the park and surrounding land depends upon creative techniques and recommendations, many still forthcoming. Ecological,
sociological, legal, and economic disciplines as well as the managing agency should all contribute to these recommendations.
Platforms for change include legislation, institutional policies, communication, education, management techniques, and ethics. 相似文献
956.
From spatial models to spatial evaluation in the analysis of wetland restoration in the Vecht river basin 总被引:1,自引:0,他引:1
Alison J. Gilbert Marjan van Herwijnen Carolin M. Lorenz 《Regional Environmental Change》2004,4(2-3):118-131
Water tables are strictly controlled throughout much of the Netherlands. Higher water tables could permit the restoration of wetland ecosystems. Deriving benefits from this requires the spatial matching of physical planning, eco-hydrological processes, and economic activities. This paper reports on a study combining spatial analysis and disciplinary integration to assess management strategies for the Vecht river basin in the Netherlands. The paper addresses two research questions. How can the information generated by spatial models be condensed into performance indicators for the evaluation of strategies? How can spatial information be retained in the evaluation, and does this lead to different rankings and/or insights? Procedures for the construction of performance indicators for three criteria – net present value, environmental quality and spatial equity – are presented. The evaluation concludes that recreation and higher water tables provide a means for restoration, recouping of costs, and stimulating regional incomes. Maintenance of spatial detail led to different insights, and in particular indicated uncertainty about this conclusion. 相似文献
957.
Integrated Coastal Zone Management as a strategy for achieving conservation and sustainable multiple use of the coastal zone
includes various types of management initiatives. Due to natural phenomena such as tides and winds and to social and economic
activities, coastal areas undergo transformation. Coastal erosion and the disappearance of beaches as a result of wrong planning
decisions and lack of effective legislation are among the most damaging effects and to reverse them requires application of
a series of engineering techniques. Beach nourishment projects as a way towards shore protection and utilization through recreational
purposes in the Spanish and Italian coasts are noteworthy in this respect.
In beach nourishment projects, the roles of various entities, both public and private, should be clearly indicated and in
the evaluation and execution stage a series of questions should be answered for the successful completion of any nourishment
project. Past projects in the Mediterranean and experiences from recent Italian projects in Anzio and Nettuno confirm this.
For example, dredging of the entrance channel of the port of Anzio enabled middle-sized ferryboats once again to enter the
port (which had not been possible before). This will in turn increase the tourism potential of the town. Nourishment of two
beaches at these sites prevented further erosion and provided more area for recreational purposes. Expected economic contribution
of beach nourishments to the regional authority was estimated for Nettuno and Anzio; the resulting theoretical payback period
was found to be 3 yr for the former and 15 yr for the latter. 相似文献
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