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In the United States, the Clean Water Act requires mitigation for wetlands that are negatively impacted by dredging and filling
activities. During the mitigation process, there generally is little effort to assess function for mitigation sites and function
is usually inferred based on vegetative cover and acreage. In our study, hydrogeomorphic (HGM) functional assessment models
were used to compare predicted and potential levels of functional capacity in created and natural reference wetlands. HGM
models assess potential function by measurement of a suite of structural variables and these modeled functions can then be
compared to those in natural, reference wetlands. The created wetlands were built in a floodplain setting of a valley in central
Pennsylvania to replace natural ridge-side slope wetlands. Functional assessment models indicated that the created sites differed
significantly from natural wetlands that represented the impacted sites for seven of the ten functions assessed. This was
expected because the created wetlands were located in a different geomorphic setting than the impacted sites, which would
affect the type and degree of functions that occur. However, functional differences were still observed when the created sites
were compared with a second set of reference wetlands that were located in a similar geomorphic setting (floodplain). Most
of the differences observed in both comparisons were related to unnatural hydrologic regimes and to the characteristics of
the surrounding landscape. As a result, the created wetlands are not fulfilling the criteria for successful wetland mitigation. 相似文献
2.
生态企业的构架与考核指标的探讨 总被引:3,自引:0,他引:3
从论述生态企业的构架———经营思想、理念、生产方式、环境管理、环境建设入手 ,对生态企业创建的考核指标进行了探讨 ,提出了五个方面共 2 5项指标的考核体系 ,为生态企业的创建及验收提供了依据。 相似文献
3.
The US Army Corps of Engineers often requires wetland creation or restoration as compensation for wetlands damaged during
development. These wetlands are typically monitored postconstruction to determine the level of compliance with respect to
site-specific performance standards. However, defining appropriate goals and measuring success of restorations has proven
difficult. We reviewed monitoring information for 76 wetlands constructed between 1992 and 2002 to summarize the performance
criteria used to measure progress, assess compliance with those criteria, and, finally, to evaluate the appropriateness of
those criteria. Goals were overwhelmingly focused on plant communities. Attributes used to assess the quality of restored
plant communities, including percent native species and the Floristic Quality Index, increased over time but were apparently
unrelated to the number of species planted. Compliance frequencies varied depending on site goals; sites often failed to comply
with criteria related to survival of planted vegetation or requirements that dominant plant species should not be exotic or
weedy, whereas criteria related to the establishment of cover by vegetation or by wetland-dependent plants were often met.
Judgment of a site’s success or failure was largely a function of the goals set for the site. Some performance criteria were
too lenient to be of value in distinguishing failed from successful sites, whereas other criteria were unachievable without
more intensive site management. More appropriate goals could be devised for restored wetlands by basing performance standards
on past performance of similar restorations, identifying consistent temporal trends in attributes of restored sites, and using
natural wetlands as references. 相似文献
4.
Cosmic vacuum energy decay and creation of cosmic matter 总被引:1,自引:0,他引:1
In the more recent literature on cosmological evolutions of the universe, the cosmic vacuum energy has become a nonrenouncable
ingredient. The cosmological constant Λ, first invented by Einstein, but later also rejected by him, presently experiences an astonishing revival. Interestingly
enough, it acts like a constant vacuum energy density would also do. Namely, it has an accelerating action on cosmic dynamics,
without which, as it appears, presently obtained cosmological data cannot be conciliated with theory. As we are going to show
in this review, however, the concept of a constant vacuum energy density is unsatisfactory for very basic reasons because
it would claim for a physical reality that acts upon spacetime and matter dynamics without itself being acted upon by spacetime
or matter. 相似文献
5.
《Environmental Communication: A Journal of Nature and Culture》2013,7(4):494-500
This paper offers a brief comment/analysis of an abridged version of America's Best Idea that was produced and distributed by Earth Ministry (with WETA's approval). There were two versions (one for Christian audiences and the other for "everyone else," i.e. interfaith) that were distributed, along with a study guide, that use Ken Burns' film to teach about/endorse creation care. This paper discusses the ways in which the film is edited to highlight its already salient "God and country" themes and to suggest that this version of the film should prompt critics to reconsider the entirety of (the original) America's Best Idea as a more complex statement of faith/nationalism and to consider the extent to which both of these films suggest a privatized, personal environmental agenda. In other words, the broader discourses of creation care threaten to move environmental concerns out of the realm of policy/public/governance (unless articulated publicly to faith-based justifications) and into the realm of the individual's relationship with God first…and others (family, community, nation, world, and various assemblages, i.e. capitalism) second. 相似文献
6.
李砥 《中国环境管理干部学院学报》2002,12(4):76-78
现代艺术设计教学跟上时代,应理清授课思路,鼓励学生的创造,启发学生的想象力,开发学生的潜在智慧,培养学生有机的运动的思维方式,以发扬个性,来寻求自己的艺术语言和发展道路。 相似文献
7.
Community Structure and Quality After 10 Years in Two Central Ohio Mitigation Bank Wetlands 总被引:1,自引:1,他引:0
We evaluate two 10-year-old mitigation bank wetlands in central Ohio, one created and one with restored and enhanced components,
by analysis of vegetation characteristics and by comparison of the year-10 vegetation and macroinvertebrate communities with
reference wetlands. To assess different measures of wetland development, we compare the prevalence of native hydrophytes with
an index of floristic quality and we evaluate the predictability of these parameters in year 10, given 5 years of data. Results
show that the mitigation wetlands in this study meet vegetation performance criteria of native hydrophyte establishment by
year 5 and maintain these characteristics through year 10. Species richness and floristic quality, as well as vegetative similarity
with reference wetlands, differ among mitigation wetlands in year 1 and also in their rate of change during the first 10 years.
The prevalence of native hydrophytes is reasonably predictable by year 10, but 5 years of monitoring is not sufficient to
predict future trends of floristic quality in either the created or restored wetland. By year 10, macroinvertebrate taxa richness
does not statistically differ among these wetlands, but mitigation wetlands differ from reference sites by tolerance index
and by trophic guild dominance. The created wetland herbivore biomass is significantly smaller than its reference, whereas
detritivore biomass is significantly greater in the created wetland and smaller in the restored wetland as compared with respective
reference wetlands. These analyses illustrate differences in measures of wetland performance and contrast the monitoring duration
necessary for legal compliance with the duration required for development of more complex indicators of ecosystem integrity. 相似文献
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