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  • Articles  (15)
  • Disturbance  (14)
  • Chemistry
  • United States
  • 2005-2009
  • 2000-2004
  • 1990-1994  (15)
  • Energy, Environment Protection, Nuclear Power Engineering  (15)
  • 1
    Electronic Resource
    Electronic Resource
    Recovery of lotic periphyton communities after disturbance (1990)
    Springer
    Environmental management 14 (1990), S. 589-604 
    Details
    ISSN: 1432-1009
    Keywords: Desiccation ; Disturbance ; Floods ; Periphyton ; Streams ; Succession ; Toxic pollutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Periphyton communities represent potentially excellent candidates for assessing the recovery of lotic ecosystems after disturbance. These communities are ubiquitous, relatively easy to sample and measure (in terms of total community biomass), have short generation times, and may influence the recovery rates of higher trophic levels. The first section of this article analyzes how site availability, species availability, and differential species performance influence periphyton successional dynamics. This background information provides a foundation for understanding how periphytic organisms respond after a disturbance. The second section of this article analyzes how periphyton communities respond to four different types of disturbance (flood events, desiccation, organic nutrient enrichment, and toxic metal exposure). Although data are limited, it is concluded that the fast growth rates and short generation times of periphytic organisms, coupled with their flexible life history strategies and good dispersal ability, allow lotic periphyton communities to recover relatively quickly after a disturbance. In addition, disturbance type and severity, local environmental conditions, and site-specific factors also will influence recovery rates. Future research needs include a better understanding of: (1) what periphyton property(ies) would serve as the best index of recovery; (2) whether or not the robustness of this index varies among different environments and different disturbances; (3) interactions between autotrophs and heterotrophs within the periphyton mat, particularly with respect to nutrient cycling; (4) competitive interactions among organisms; (5) functional redundancy of organisms; and (6) the influence of the riparian zone and channel geomorphology on periphyton recovery rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394711
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  • 2
    Electronic Resource
    Electronic Resource
    Recovery of lotic communities and ecosystems from disturbance—A narrative review of case studies (1990)
    Springer
    Environmental management 14 (1990), S. 547-569 
    Details
    ISSN: 1432-1009
    Keywords: Lotic ecosystems ; Streams ; Rivers ; Disturbance ; Recovery ; Case studies ; Review
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We present a narrative account of case studies of the recovery of flowing water systems from disturbance, focusing on the investigators' conclusions about recovery time and the factors contributing to recovery. We restrict our attention to case studies in which the recovery of some biological property of the system has been examined, excluding those that deal only with physical or chemical properties. Although natural processes and rates of recovery are emphasized, studies of reclamation or restoration of damaged ecosystems are included where they contribute to an understanding of recovery processes. For the majority of studies examined, the systems recovered quite rapidly. The most commonly cited reasons for short recovery times were: (1) life history characteristics that allowed rapid recolonization and repopulation of the affected areas, (2) the availability and accessibility of unaffected up-stream and downstream areas and internal refugia to serve as sources of organisms for repopulation, (3) the high flushing rates of lotic systems that allowed them to quickly dilute or replace polluted waters, and (4) the fact that lotic systems are naturally subjected to a variety of disturbances and the biota have evolved life history characteristics that favor flexibility or adaptability. In general, longer recovery times were observed in disturbances, such as channelization, that resulted in alterations to physical conditions. This review also indicates that much of our knowledge of recovery in lotic ecosystems is fragmented and uncoordinated. In addition to establishing the bounds of recovery time, our review identifies some research gaps that need to be filled.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394709
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  • 3
    Electronic Resource
    Electronic Resource
    Environmental variation, life history attributes, and community structure in stream fishes: Implications for environmental management and assessment (1990)
    Springer
    Environmental management 14 (1990), S. 621-628 
    Details
    ISSN: 1432-1009
    Keywords: Anthropogenic ; Community structure ; Disturbance ; Environmental management ; Environmental variation ; Index of biotic integrity ; Life history characteristics ; Longitudinal variation ; Recovery from disturbance ; Stream fishes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Fishes in midwestern streams of the United States experience strong upstream—downstream gradients in natural environmental variability. Upstream fishes experience greater temporal variability in physical—chemical conditions than downstream fishes, particularly in intermittent streams. Associated with these changes in environmental variability, basic changes occur in life history attributes and temporal variation in community structure of stream fishes. As a whole, upstream species have a shorter life-span, smaller body size, and earlier sexual maturity than downstream species. Descriptive studies also suggest upstream species exhibit more rapid recolonization after severe physical disturbance than downstream species, and fish community structure is temporally more variable in upstream than downstream areas. These longitudinal differences in life history characteristics suggest that upstream fish communities will exhibit more rapid recovery from severe anthropogenic disturbances than downstream fish communities. The greater temporal variability of fish community structure in upstream areas also suggests it will be more difficult in upstream than downstream areas to use fish-based indices to distinguish whether subtle changes in environmental quality are due to natural or anthropogenic disturbances. Long-term monitoring of fishes throughout drainage basins is critically needed to establish more precisely the natural range of variation in community structure. Such monitoring will allow regulatory agencies to distinguish, with greater confidence, the influence of anthropogenic disturbances on stream fishes from the influence of natural environmental variation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394713
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  • 4
    Electronic Resource
    Electronic Resource
    Island biogeographical theory: Can it be used to predict lotic recovery rates? (1990)
    Springer
    Environmental management 14 (1990), S. 737-753 
    Details
    ISSN: 1432-1009
    Keywords: Island biogeography ; Colonization ; Recovery ; Disturbance ; Equilibrium ; Predictive models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Classic island biogeographic theory predicts that equilibrium will be reached when immigration and extinction rates are equal. These rates are modified by number of species in source area, number of intermediate islands, distance to recipient island, and size of intermediate islands. This general model has been variously modified and proposed to be a stochastic process with minimal competitive interaction or heavily deterministic. Predictive models of recovery (regardless of the end point chosen) have been based on the appropriateness of the MacArthur-Wilson models. Because disturbance frequency, severity, and intensity vary in their effect on community dynamics, we propose that disturbance levels should first be defined before evaluating the applicability of island biogeographical theory. Thus, we suggest a classification system of four disturbance levels based on recovery patterns by primary and secondary succession and faunal organization by primary (invasion of vacant areas) and secondary (remnant of previous community remains) processes. Level 1A disturbances completely destroy communities with no upstream or downstream sources of colonizers, while some component of near surface interstitial or hyporheic flora and fauna survive level 1B disturbances. Recovery has been reported to take from five years to longer than 25 years, when most invading colonists do not have an aerial form. Level 2 disturbances destroy the communities but leave upstream and downstream colonization sources (level 2A) and, sometimes, a hyporheic pool of colonizers (level 2B). Recovery studies have indicated primary succession and faunal structuring patterns (2A) with recovery times of 90–400 days or secondary succession and faunal structuring patterns (2B) with recovery times of 40–250 days. Level 3 disturbances result in reduction in species abundance and diversity along a stream reach; level 4 disturbances result in reduction of abundance and diversity in discrete patches. Both disturbance types lead to secondary succession and secondary faunal organization. Recovery rates can be quite rapid, varying from less than 10 days to 100 or more days. We suggest that island biogeographical models seem appropriate to recovery by secondary processes after level 3 and 4 disturbances, where competition may be an important organizing factor, while models of numerical abundance and resource tracking are probably of better use where community development is by primary succession (levels 1 and 2). Development of predictive recovery models requires research that addresses a number of fundamental questions. These include the role of hydrologic patterns on colonization dynamics, the role of nonaerial colonizers in recovery from level 1 disturbances, and assessment of the impact of changes in the order of invasion by colonizers of varying energetic efficiencies. Finally, we must be able to assemble these data and determine whether information that guides community organization at one level of disturbance can provide insights into colonization dynamics at other levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394722
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  • 5
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    Electronic Resource
    Application of ecological theory to determining recovery potential of disturbed lotic ecosystems: Research needs and priorities (1990)
    Springer
    Environmental management 14 (1990), S. 755-762 
    Details
    ISSN: 1432-1009
    Keywords: Disturbance ; Recovery ; Prediction ; Lotic ecosystems ; Research needs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This article summarizes the views of aquatic scientists who gathered to assess the ability of stream ecosystem theory to predict recovery from disturbance. Two views of disturbance were evident: a discrete removal of organisms vs an unusual deviation from normal. These were perceived as applying to different scales and/or objectives. Long-term information is required from both points of view to define recovery. Recovery also may be defined in different ways, but it is clear that recovery has both spatial and temporal components, and includes both physical and biological processes. Consensus was very strong that a major role (and challenge) for theory lies in the understanding of spatial aspects, temporal scales, coupling of physics and biology, and the interaction of these features in recovery processes. Some progress is evident in the articles of this volume, but among the topics identified as critical for further theoretical contributions were: homogeneous vs heterogeneous distribution of disturbance, local extent of disturbance relative to a regional context, critical vs noncritical patches (size and location) of disturbance at different spatial scales and temporal frequencies, delineation of reversible and nonreversible processes, and physical and biological constraints on the time frame for recovery. Such concepts need attention across different types of lotic ecosystems. Thus, there was strong consensus that a national monitoring system of representative lotic ecosystems within ecological regions be established. The purpose of this monitoring system would be to acquire long-term data on natural variability, to establish viable indicators of spatial and temporal aspects of recovery, and to develop and test emerging theoretical developments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394723
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  • 6
    Electronic Resource
    Electronic Resource
    Recovery of temperate-stream fish communities from disturbance: A review of case studies and synthesis of theory (1992)
    Springer
    Environmental management 16 (1992), S. 33-53 
    Details
    ISSN: 1432-1009
    Keywords: Fish ; Recovery ; Disturbance ; Stream ; Communities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract To evaluate the relative effect of autecologic factors, site-specific factors, disturbance characteristics, and community structure on the recovery of temperate-stream fish communities, we reviewed case histories for 49 sites and recorded data on 411 recovery end points. Most data were derived from studies of low-gradient third- or fourth-order temperate streams located in forested or agricultural watersheds. Species composition, species richness, and total density all recovered within one year for over 70% of systems studied. Lotic fish communities were not resilient to press disturbances (e.g., mining, logging, channelization) in the absence of mitigation efforts (recovery time 〉5 to 〉52 yr) and in these cases recovery was limited by habitat quality. Following pulse disturbances, autecological factors, site-specific factors, and disturbance-specific factors all affected rates of recovery. Centrarchids and minnows were most resilient to disturbance, while salmonid populations were least resilient of all families considered. Species within rock-substrate/nest-spawning guilds required significantly longer time periods to either recolonize or reestablish predisturbance population densities than did species within other reproductive guilds. Recovery was enhanced by the presence of refugia but was delayed by barriers to migration, especially when source populations for recolonization were relatively distant. Median population recovery times for systems in which disturbances occurred during or immediately prior to spawning were significantly less than median recovery times for systems in which disturbances occurred immediately after spawning. There was little evidence for the influence of biotic interactions on recovery rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02393907
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  • 7
    Electronic Resource
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    Overview of case studies on recovery of aquatic systems from disturbance (1990)
    Springer
    Environmental management 14 (1990), S. 571-587 
    Details
    ISSN: 1432-1009
    Keywords: Recovery ; Disturbance ; Aquatic ecosystems ; Macroinvertebrates ; Fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract An extensive review of the published literature identified more than 150 case studies in which some aspect of resilience in freshwater systems was reported. Approximately 79% of systems studied were lotic and the remainder lentic. Most of the stressor types were chemical with DDT (N=29) and rotenone (N=15) the most common. The most common nonchemical stressors were logging activity (N=16), flooding (N=8), dredging (N=3), and drought (N=7). The variety of endpoints to which recovery could be measured ranged from sparse data for phytoplankton (N=13), periphyton (N=6), and macrophytes (N=8) to relatively more data for fish (N=412) and macroinvertebrates (N=698). Unfortunately the same characteristics were rarely measured consistently among sites. For example, with respect to fish, more than 30 different species were studied and recovery was measured in many ways, most commonly on the basis of: (1) first reappearance of the species, (2) return time of predisturbance densities, and (3) return time of predisturbance average individual size. Based on these criteria, all systems in these studies seem to be resilient to most disturbances with most recovery times being less than three years. Exceptions included when (1) the disturbance resulted in physical alteration of the existing habitat, (2) residual pollutants remained in the system, or (3) the system was isolated and recolonization was suppressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394710
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  • 8
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    Disturbance regimes, resilience, and recovery of animal communities and habitats in lotic ecosystems (1990)
    Springer
    Environmental management 14 (1990), S. 647-659 
    Details
    ISSN: 1432-1009
    Keywords: Community ; Disturbance ; Ecosystem ; Historical effects ; Recovery ; Resilience ; River basin ; Scale ; Sediments ; Stream
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Disturbance regime is a critical organizing feature of stream communities and ecosystems. The position of a given reach in the river basin and the sediment type within that reach are two key determinants of the frequency and intensity of flow-induced disturbances. We distinguish between predictable and unpredictable events and suggest that predictable discharge events are not disturbances. We relate the dynamics of recovery from disturbance (i.e., resilience) to disturbance regime (i.e., the disturbance history of the site). The most frequently and predictably disturbed sites can be expected to demonstrate the highest resilience. Spatial scale is an important dimension of community structure, dynamics, and recovery from disturbance. We compare the effects on small patches (⩽1 m2) to the effects of large reaches at the river basin level. At small scales, sediment movements and scour are major factors affecting the distribution of populations of aquatic insects or algae. At larger scales, we must deal with channel formation, bank erosion, and interactions with the riparian zone that will affect all taxa and processes. Our understanding of stream ecosystem recovery rests on our grasp of the historical, spatial, and temporal background of contemporary disturbance events.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394715
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  • 9
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    Recovery processes in lotic ecosystems: Limits of successional theory (1990)
    Springer
    Environmental management 14 (1990), S. 725-736 
    Details
    ISSN: 1432-1009
    Keywords: Succession ; Disturbance ; Stability ; Streams ; Ecosystems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The concept of succession has a distinguished history in general ecology and has been applied to stream ecosystems with some success. Succession in streams is largely secondary, follows initial floristics models, and occurs through a variety of mechanisms. The process is moderately predictable but is highly influenced by “climatic” factors, particularly nutrient chemistry. In desert streams, succession does not result in a climax state. While evidence is slim, succession may not be a significant process in streams of certain types or in certain regions. Successional theory is difficult to apply in spatially heterogeneous, hierarchically organized ecosystems. It also suffers in being only one component of a better integrated concept, that of ecosystem stability, which deals more directly with disturbance and ecosystem resistance in addition to resilience (which encompasses succession). Succession has so suffered from a half century of confusion that a strong case can be made for abandoning the term, at least as it applies in streams, in favor of the broader view provided by stability theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394721
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  • 10
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    Tundra disturbance and ecosystem production: Implications for impact assessment (1992)
    Springer
    Environmental management 16 (1992), S. 485-494 
    Details
    ISSN: 1432-1009
    Keywords: Tundra ; Production ; Disturbance ; Impact assessment ; Thermokarst
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Environmental regulations governing industrial activities in tundra environments stem largely from the expected ecological effects of the activities. One of the major ecological effects of industrial activities is the surface subsidence associated with thermokarst, which can result in changes in primary and secondary production. The primary production changes associated with thermokarst are strongly governed by three ecosystem properties—soil temperature, water regime, and nutrient availability. Most disturbances set in motion a more-or-less predictable sequence of landscape change related to these properties: soil warming, thermokarst, surface flooding, accelerated organic matter decomposition, and increased nutrient availability. The warmed soil and the enhanced nutrient availability typically lead to increased annual primary production, increased dominance by graminoids, and reduced plant species diversity. These vegetational changes may in turn potentially enhance secondary production, but in general these second-level responses have yet to be quantified. More information is needed about the food-chain effects of tundra landscape disturbances before regulators can make well-informed predictions of impacts or plan useful habitat rehabilitation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394124
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  • 11
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    Recovery of lotic macroinvertebrate communities from disturbance (1990)
    Springer
    Environmental management 14 (1990), S. 605-620 
    Details
    ISSN: 1432-1009
    Keywords: Macroinvertebrates ; Communities ; Recovery ; Disturbance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Ecosystem disturbances produce changes in macrobenthic community structure (abundances, biomass, and production) that persist for a few weeks to many decades. Examples of disturbances with extremely long-term effects on benthic communities include contamination by persistent toxic agents, physical changes in habitats, and altered energy inputs. Stream size, retention, and local geomorphology may ameliorate the influence of disturbances on invertebrates. Disturbances can alter food webs and may select for favorable genotypes (e.g., insecticidal resistance). Introductions of pesticides into lotic ecosystems, which do not result in major physical changes within habitats, illustrate several factors that influence invertebrate recovery time from disturbance. These include: (1) magnitude of original contamination, toxicity, and extent of continued use; (2) spatial scale of the disturbance; (3) persistence of the pesticide; (4) timing of the contamination in relation to the life history stages of the organisms; (5) vagility of populations influenced by pesticides; and (6) position within the drainage network. The ability of macroinvertebrates to recolonize denuded stream habitats may vary greatly depending on regional life histories, dispersal abilities, and position within the stream network (e.g., headwaters vs larger rivers). Although downstream drift is the most frequently cited mechanism of invertebrate recolonization following disturbance in middle- and larger-order streams, evidence is presented that shows aerial recolonization to be potentially important in headwater streams. There is an apparent stochastic element operating for aerial recolonization, depending on the timing of disturbance and flight periods of various taxa. Available evidence indicates that recolonization of invertebrate taxa without an aerial adult stage requires longer periods of time than for those that possess winged, terrestrial adult stages (i.e., most insects). Innovative, manipulative experiments are needed in order to address recolonization mechanisms of animals inhabiting streams that differ in size, latitude, disturbance frequency and magnitude, as well as the potential influence of early colonists on successional sequences of species following disturbance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394712
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  • 12
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    Physical habitat template of lotic systems: Recovery in the context of historical pattern of spatiotemporal heterogeneity (1990)
    Springer
    Environmental management 14 (1990), S. 629-645 
    Details
    ISSN: 1432-1009
    Keywords: Spatiotemporal heterogeneity ; Physical habitat template ; Streams ; Disturbance ; Recovery ; Community structure ; Natural selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Spatial and temporal environmental heterogeneity in lotic ecosystems can be quantitatively described and identified with characteristic levels of ecological organization. The long-term pattern of physicochemical variability in conjunction with the complexity and stability of the substratum establishes a physical habitat template that theoretically influences which combinations of behavioral, physiological and life history characteristics constitute appropriate “ecological strategies” for persistence in the habitat. The combination of strategies employed will constrain ecological response to and recovery from disturbance. Physical habitat templates and associated ecological attributes differ geographically because of biogeoclimatic processes that constrain lotic habitat structure and stability and that influence physicochemical variability and disturbance patterns (frequency, magnitude, and predictability). Theoretical considerations and empirical studies suggest that recovery from natural and anthropogenic disturbance also will vary among lotic systems, depending on historical temporal variability regime, degree of habitat heterogeneity, and spatial scale of the perturbation. Characterization of physical habitat templates and associated ecological dynamics along gradients of natural disturbance would provide a geographic framework for predicting recovery from anthropogenic disturbance for individual streams. Description of lotic environmental templates at the appropriate spatial and temporal scale is therefore desirable to test theoretical expectations of biotic recovery rate from disturbance and to guide selection of appropriate reference study sites for monitoring impacts of anthropogenic disturbance. Historical streamflow data, coupled with stream-specific thermal and substratum-geomorphologic characteristics, are suggested as minimum elements needed to characterize physical templates of lotic systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394714
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  • 13
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    Disturbance and recovery of large floodplain rivers (1990)
    Springer
    Environmental management 14 (1990), S. 699-709 
    Details
    ISSN: 1432-1009
    Keywords: Disturbance ; Recovery ; River ; Ecosystem ; Mississippi River ; Illinois River
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Disturbance in a river-floodplain system is defined as an unpredictable event that disrupts structure or function at the ecosystem, community, or population level. Disturbance can result in species replacements or losses, or shifts of ecosystems from one persistent condition to another. A disturbance can be a discrete event or a graded change in a controlling factor that eventually exceeds a critical threshold. The annual flood is the major driving variable that facilitates lateral exchanges of nutrients, organic matter, and organisms. The annual flood is not normally considered a disturbance unless its timing or magnitude is “atypical.” The record flood of 1973 had little effect on the biota at a long-term study site on the Mississippi River, but the absence of a flood during the 1976–1977 Midwestern drought caused short- and long-term changes. Body burdens of contaminants increased temporarily in key species, because of increased concentration resulting from reduced dilution. Reduced runoff and sediment input improved light penetration and increased the depth at which aquatic macrophytes could grow. Developing plant beds exerted a high degree of biotic control and were able to persist, despite the resumption of normal floods and turbidity in subsequent years. In contrast to the discrete event that disturbed the Mississippi River, a major confluent, the Illinois River, has been degraded by a gradual increase in sediment input and sediment resuspension. From 1958 to 1961 formerly productive backwaters and lakes along a 320-km reach of the Illinois River changed from clear, vegetated areas to turbid, barren basins. The change to a system largely controlled by abiotic factors was rapid and the degraded condition persists. Traditional approaches to experimental design are poorly suited for detecting control mechanisms and for determining the critical thresholds in large river-floodplains. Large river-floodplain systems cannot be manipulated or sampled as easily as small streams, and greater use should be made of man-made or natural disturbances and environmental restoration as opportunistic experiments to measure thresholds and monitor the recovery process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394719
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  • 14
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    Old distribution procedure of both water and matter fluxes in floodplains of western Europe: Impact on present vegetation (1994)
    Springer
    Environmental management 18 (1994), S. 203-221 
    Details
    ISSN: 1432-1009
    Keywords: Diking ; Disturbance ; Engineering procedures ; Fertilization ; History ; Isère River ; Landscape heterogeneity ; Land-use changes ; Piedmont areas ; Warping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract In France and the United States it has been shown that strong linkages exist between vegetation and alluvial landforms within homogeneous river stretches characterized by geomorphological processes, flood duration, flood magnitude, flood frequency, and sediment size. Furthermore, perturbations induced by man (such as embankments and damming) have been shown to have an effect on both succession and plant distribution patterns. Yet, in numerous cases it is not possible to find either the communities or the plants whose presence might be predicted by reference to the river section characteristics (such as straight, braided, anastomosed, or meandering channels) or by reference to perturbation effects well known in piedmont valleys (such as variations of the water-table depth, variations of magnitude, and frequency and duration of floods). Unexpected species, new communities, and even new successional sequences are often observed. The presence of new alluvial forms explains these differences. An “artificial” substratum generated by an old human perturbation (limited in the time) has been established in the past; consequently, the natural distribution patterns of water and matter flows have been disturbed. Archive research has enabled a classification of abandoned systems that were commonly used during the 16th, 17th, 18th, and 19th centuries on European floodplains. Several case studies were chosen in order to illustrate and explain the importance of stream corridor history. The example of the Isère River valley, downstream from Albertville, is chosen to highlight the heterogeneity of the vegetation mosaïc pattern outside the dikes. The historical reconstruction explains the role of the additional disturbances that cause deviation from the system evolution patterns.
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    URL: http://dx.doi.org/10.1007/BF02393762
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  • 15
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    How efficient are national environmental standards? A benefit-cost analysis of the United States experience (1991)
    Springer
    Environmental and resource economics 1 (1991), S. 385-413 
    Details
    ISSN: 1573-1502
    Keywords: Environmental standards ; environmental regulations ; benefit-cost ; cost-benefit ; United States ; efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Economics
    Notes: Abstract This paper summarizes the results of the first systematic, geographically-specific efficiency assessment of the U.S. experience with national environmental standards and with alternative approaches to establishing those standards. This ex-post evaluation assessed the net benefits that resulted from EPA's regulation of conventional air and water pollutants from the pulp and paper industry between 1973 and 1984. The paper compares the benefit-cost efficiencies of the three dominant regulatory approaches: technology, ambient, and benefits. Unlike previous studies, which assessed benefits and costs on a national basis, the study estimates both costs and benefits on a facility-by-facility basis. The analysis shows how the efficiency of national environmental regulations can vary dramatically at local levels. The authors conclude that the technology-based standards for water pollution management failed as an efficient environmental strategy. The costs clearly exceeded the benefits in the aggregate, as well as in the specific in most situations. Benefits exceeded costs at only 11 of the 68 mills investigated. The ambient based standards for air pollution management succeeded as an environmental strategy in the aggregate, but succeeded in the specific for only one-third of the mills (22 of 60 mills). The benefits-based standards for air pollution management also succeeded in the aggregate as well as in the specific for about one-half of the mills. Benefits exceeded costs at 29 of the 60 mills investigated. The results of the study point to two major conclusions. First, a regulatory policy that is based on some measure of environmental results, either ambient-based or benefits-based, will be more efficient than a policy that ignores environmental results. Second, truly efficient policies for reducing environmental risks require pollution mitigation decisions that take into account local conditions. These include not only the changes in local ambient conditions, but also the number of people who will benefit from pollution reduction decisions. This latter conclusion suggests that national environmental standards per se may be inefficient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377494
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