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491.
492.
从目前水资源匮乏和水质污染的状况入手,分析了影响原因,并从加强污染源管理、小城镇环保设施建设、控制农业污染、提高利用率、加强环境宣传力度等几方面提出保护水资源的对策与建议. 相似文献
493.
The Euler Number as an Index of Spatial Integrity of Landscapes: Evaluation and Proposed Improvement
The spatial integrity of a habitat or landscape is determined by the occurrence of habitat fragments and of perforations inside
them. A landscape is said to have less spatial integrity with increasing numbers of fragments and perforations. The Euler
number (ε) is a numerical measure of spatial integrity, based upon the difference |n
f
−n
p
| between the number of fragments (n
f
) and the number of perforations (n
p
). In this contribution, ε is evaluated, and an improvement is presented as a new index ε*, which is a combination of two
metrics (ε
i
, ε
d
) based on n
f
and n
p
. The term ε
i
quantifies the intensity of perforation and/or fragmentation. The term ε
d
measures the extent to which fragmentation predominates perforation, and vice versa. The intensity and dominance measures
are combined into an Euclidean distance measure, generating the new ensemble value ε*, calculated as ε*= (n
f
+n
p
)−1√[1 +n
f
2]. Use, sensitivity, and application of ε*, ε
i
, and ε
d
are illustrated using percolation maps. Application of the new metrics by environmental scientists is encouraged because
(1) no negative values can be generated with ε*, ε
i
, and ε
d
; (2) the range of ε*, ε
i
, and ε
d
is fixed; (3) process dominance and intensity are both assessed; (4) ε*, ε
i
, and ε
d
are easy to calculate and to interpret; and (5) ε* is not only based upon |n
f
−n
p
|, as ε is. Guidelines for practical use by means of a biplot of ε
i
and ε
d
are given. 相似文献
494.
中山市城市绿地系统的生物多样性特色及新的发展思路 总被引:6,自引:0,他引:6
中山市在城市绿地规划中利用丰富的生物多样性资源,遵循多样性保护与利用相结合的原则,创造出健康优美的城市生态环境;本文阐述了中山市城市绿地系统的生物多样性特色及新的发展思路,可为珠江三角洲地区其它城市的绿地系统规划提供参考和借鉴。 相似文献
495.
Fast economic and social changes in recent years in China have brought massive expansion, redevelopment, and restructuring
of cities. These changes offer cities the opportunity to improve environmental quality through urban green spaces (UGSs) and
to address the challenges of meeting community aspirations. This study explored peoples’ minds concerning UGSs in Guangzhou
city in south China in relation to the following: (1) knowledge and perception of 25 ecosystem services and 8 negative impacts;
(2) attitude toward site condition and management; (3) expectation of landscape design; and (4) preference ranking of venues.
A questionnaire was designed to solicit opinions from 340 respondents randomly chosen from residents living in the study area.
The results indicated widespread recognition of ecosystem services and strong support of UGS programs. Negative responses
were weakly expressed. Amelioration of urban microclimate and environmental quality were emphasized. Environmental functions
stressed in publicity programs, together with aggravating environmental problems in the city, tended to focus respondents’
attention on UGS benefits. Wildlife habitat, species conservation and other natural ecosystem services drew limited concerns.
Awareness of economic benefits was very low. Visual-landscape contributions with strong preference for naturalistic design
and recreational benefits were highlighted. Compared with other countries, Guangzhou residents were characterized by visual–scenic–recreation
orientation and pragmatic–utilitarian perception of UGSs, reflecting underlying differences in the understanding of inherent
ecosystem services of green spaces. Relevant UGS policies and practices could adopt the approaches of market survey, citizen
participation, and precision planning in order to meet increasingly mature and refined demands. Citizens’ understanding of
high-order ecosystem services could be enhanced to encourage appreciation of nature and their associated benefits. 相似文献
496.
Richard R. Harris 《Environmental management》1988,12(2):219-228
Ten streams in the eastern Sierra Nevada, California, were classified into six geomorphic valley types and sampled to determine environmental and riparian vegetation conditions. The geomorphic valley types were relatively uniform geologically and hydrologically, collectively representing the range of stream environments in the region. There were significant associations between the geomorphic valley types and riparian community composition. These geomorphic-vegetation units are landscape elements which comprise the riparian ecosystems in the region. They differ in their ecological charactersitics and sensitivity to management. The system of landscape elements can be used to classify streams for the purposes of resource inventory, detailed ecological studies, and impact prediction. 相似文献
497.
在近年来国内休闲农业快速发展的背景下,由于缺乏对其非使用价值的正确认识和判断,出现了高速增长与效果欠佳的矛盾,如何科学评价休闲农场开发的非使用价值,对于该产业发展具有重要意义。条件价值评估方法(CVM)是国内外评估非使用价值和支付意愿较为成熟的方法,但尚未用于对具有"三产融合"和"三生一体"特性的休闲农场的评估,本研究以福建开发较为成熟的长泰福友休闲农场为研究取样点,采用该方法探究游客对休闲农场生态景观质量的感知水平及支付意愿。结果表明:游客对福友休闲农场生态保护价值支付意愿的下限为18.26元,支付上限为23.10元,游客对福友休闲农场生态景观保护的支付意愿为96.45万元/年;提供便捷的支付渠道和公开资金的使用途径能有效提升游客购买生态景观保护价值的支付意愿;农场空气的好坏、农场的生态体验设计、农场的田园功能分区在主题设计、耕作体验形式、内容等方面的创新程度对游客生态保护的支付意愿影响较大;对于大部分拥有一定农场阅历但对农业多功能性认识不足的游客,在便捷的支付手段和珍稀植物品种的吸引下,更倾向于形成较低水平的生态保护价值支付意愿,而那些文化素质较高,特别是拥有农场、生态相关领域研究背景,对于农场生态功能性、体验养生内容拥有一定认知的游客,则愿意在更高的价格水平支付农场的生态保护价值。 相似文献
498.
文章首先对藻类污染生态学的发展历史作了简单回顾,接着对其主要研究领域(水污染对藻类的影响和藻类净化水质)及研究成果进行了综述,在此基础上指出了其今后的发展趋势。 相似文献
499.
针对城市景观水的水质状况加剧恶化,本文对比在不同情况下用氯化铁及聚合氯化铝处理景观水,探讨了投加量、搅拌速度、搅拌时间、静沉时间以及pH对景观水有机物和浊度去除率的影响.结果表明:当水样pH值在6~8之间时,投加4~6mL混凝剂后,当先中速搅拌(120 r/min)2 min,最后慢速搅拌(60 r/min)搅拌10 min.此后静沉35 min,此时CODcr去除率及浊度去除率都可达到最佳情况;其中pH为8时,硫酸铁对CODcr去除率可达82%,浊度去除率率为92%;当PH为7时PAC对城市景观水CODcr的去除可达84%,浊度去除率率为96%.聚合氯化铝的处理效果优于硫酸铁,故而得出处理城市景观水时更适合选用聚合氯化铝. 相似文献
500.
G. P. Patil J. A. Bishop W. L. Myers C. Taillie R. Vraney Denice Wardrop 《Environmental and Ecological Statistics》2004,11(2):139-164
Geographical surveillance for hotspot detection and delineation has become an important area of investigation both in geospatial ecosystem health and in geospatial public health. In order to find critical areas based on synoptic cellular data, geospatial ecosystem health investigations apply recently discovered echelon tools. In order to find elevated rate areas based on synoptic cellular data, geospatial public health investigations apply recently discovered spatial scan statistic tools. The purpose of this paper is to conceptualize a joint role for these together in the spirit of a cross-disciplinary cross-fertilization to accomplish more effective and efficient geographical surveillance for hotspot detection and delineation, and early warning system. 相似文献