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951.
Urban Flora as a Component of the Urban Ecosystems in the Taiga Zone: An Example of Karelian Cities 总被引:1,自引:0,他引:1
G. S. Antipina 《Russian Journal of Ecology》2003,34(4):215-218
Cities are areas of increased diversity of species in the taiga zone. The aboriginal fraction of Karelian flora is a stable natural system whose main characteristics are preserved in the urban flora. The adventive fraction, which is a dynamic component of the flora, has not been completely formed in the cities, as well as in eastern Fennoscandia as a whole. It has become substantially richer during the past 20–25 years. Cities of the taiga zone may serve as objects for monitoring the anthropogenic processes of flora transformation in the North. 相似文献
952.
The development of a sampling design for optimisingsampling site locations collected from a coastalmarine environment has been the purpose of the presentwork; application of statistical analysis and spatialautocorrelation methods have been carried out. Thedataset included data collected from 34 sampling sitesspaced out in the Strait of Lesbos, Greece, arrangedin a 1×1 NM grid. The coastal shallow ecosystem wassubdivided into three zones, an inner one (7stations), a middle one (16 stations) and an offshorezone (11 stations). The standard error of thechlorophyll-a concentrations in each zone hasbeen used as the criterion for the sampling designoptimisation, resulting into reallocation of thesampling sites into the three zones. The positions ofthe reallocated stations have been assessed byestimation of the spatial heterogeneity and anisotropyof chlorophyll-a concentrations usingvariograms. Study of the variance of the initialdataset of the inner zone taking into account spatialheterogeneity, revealed two different sub-areas andtherefore, the number of the inner stations has beenreassessed. The proposed methodology eliminates thenumber of sampling sites and maximises the informationof spatial data from marine ecosystems. It isdescribed as a step-by-step procedure and could bewidely applied in sampling design concerning coastalpollution problems. 相似文献
953.
Crifasi RR 《Environmental management》2005,36(5):625-639
“A skyscraper is as natural as a bird’s nest” –Alan Watts
For millennia, people have altered freshwater ecosystems directly through water development and indirectly by global change
and surrounding land-use activities. In these altered ecosystems, human impacts can be subtle and are sometimes overlooked
by the people who manage them. This article provides two case studies near Boulder, Colorado that demonstrate how perceptions
regarding these ecosystems affect their management. These examples are typical of lakes and streams along the Front Range
of Colorado that are simultaneously natural and social in origin. Although natural, many of the region’s freshwater ecosystems
are affected by ongoing ecologic, hydrologic, chemical, and geomorphic modifications produced by human activity. People and
nature are both active participants in the production of these freshwater ecosystems. The concept of “hybridity,” borrowed
from geographers and social scientists, is useful for describing landscapes of natural and social origin. Hybrid freshwater
ecosystems are features of the humanized landscape and are derived from deliberate cultural activities, nonhuman physical
and biological processes, and incidental anthropogenic disturbance. Our perceptions of “natural” freshwater ecosystems and
what definitions we use to describe them influences our view of hybrid systems and, in turn, affects management decisions
regarding them. This work stresses the importance of understanding the underlying societal forces and cultural values responsible
for the creation of hybrid freshwater ecosystems as a central step in their conservation and management. 相似文献
954.
955.
Theuplandreferstoanyplacewhoserelativealtitudeismorethan 2 0 0meters.Itmaynotonlyincludelowmountains,mediummountains,highmountainsandsky highmountains,butalsotablelands,plateaus,hills,valleysandbasinsthatlieamongthem .Itisindeedacomplexecosystemcomprisingnat… 相似文献
956.
957.
Gareth K. Phoenix Jonathan R. Leake David J. Read J. Philip Grime John A. Lee 《Water, Air, & Soil Pollution: Focus》2004,4(6):159-167
Semi-natural calcareous and acidic grasslands are known to be sensitive to increased atmospheric N deposition. However, the fate of pollutant N within these systems is unknown. This paper reports on the first studies to determine the fate of added N within a calcareous and an acidic grassland subject to long-term simulated enhanced N deposition. Intact soil/turf cores were removed from field plots treated for six years with enhanced N deposition (ambient +0, +35 and +140 kg N ha–1 year–1). Cores were inserted into lysimeters and output fluxes of N were monitored in detail. Complete N budgets—calculated from the N flux data—showed considerable accumulation of N within the treated grasslands, up to 76% and 38% of pollutant N in the calcareous and acidic grasslands respectively. In the second study, the short-term (21 day) fate of pollutant N was determined by tracing 15N labelled ammonium nitrate (+35 kg N ha–1 year–1) though the acidic and calcareous lysimeters into plant, soil and leachate pools. Up to 91% and 59% of 15N was recovered in soils and vegetation of the calcareous and acidic grasslands respectively, with negligible amounts recovered in soil extractable ammonium and nitrate (<0.3%) and in leachate (<0.02%). This rapid short-term immobilisation of pollutant N supports the long-term accumulation of the element calculated from the N flux study. 相似文献
958.
从生态学角度分析了滇池富营养化形成的原因,认为滇池富营养化是滇池流域各子生态系统受到破坏所造成的结果。提出治理滇池应该用生态学的原理和方法分别修复受到破坏的各子生态系统,恢复各子生态系统的合理结构、高效功能和协调关系,并把各子生态系统整合为一个整体协调、自我维持、自我演替的滇池流域生态系统,才能最终实现滇池富营养化治理。 相似文献
959.
960.
生态保护的基础是生态监测与生态调查,生态保护的关键则是生态系统健康评价,生态系统健康评价因素有组织、结构、活力、恢复力、系统对相邻系统的影响、投入、对人类健康的影响等,其类型有健康、较健康、亚健康、不健康、患病五级;其相应的生态恢复为生态预防、自然恢复、生态修复、生态重建;其相应的生态工程有建立自然保护区、封育、补播与放流、人工林、人工草场、人工湿地等。 相似文献