Longitudinal trends in regulated rivers: a review and synthesis within the context of the serial discontinuity concept

2013 ◽  
Vol 21 (3) ◽  
pp. 136-148 ◽  
Author(s):  
Lucy Eunsun Ellis ◽  
Nicholas Edward Jones
Keyword(s):  
Environmental Flows ◽  
Benthic Invertebrate ◽  
Trophic Levels ◽  
Empirical Estimation ◽  
Resource Subsidies ◽  
River Continuum ◽  
Regulated Rivers ◽  
Continuum Concept ◽  
Serial Discontinuity Concept ◽  
Serial Discontinuity

Dams alter the geomorphology, water quality, temperature regime, and flow regime of lotic systems influencing the resources and habitat of fish, benthic invertebrates, and lower trophic levels. Since the inception of the river continuum concept and the serial discontinuity concept (SDC), biotic and abiotic impacts below impoundments have been the focus of many lotic studies. However, recovery gradients below dams are rarely examined in sufficient detail and no current synthesis of longitudinal impacts in regulated rivers exists. This understanding is needed to build ecological relationships in regulated rivers to inform environmental flows science and management. In this review, we provide evidence for SDC predictions on physical, chemical, and biological recovery in regulated rivers. Additionally, we determine how these changes are reflected in the benthic community. Our review suggests that two recovery gradients exist in regulated rivers: (1) a longer, thermal gradient taking up to hundreds of kilometres downstream; and (2) a shorter, resource subsidy gradient recovering within 1–4 km downstream of an impoundment. Total benthic invertebrate abundance varies considerably, with both increases and reductions observed at near-dam sites and varying in recovery downstream. Much of this variability stems from the degree of flow alteration and resource subsidies from the upstream reservoir. In contrast, benthic diversity is often reduced below dams irrespective of dam location and operation with little recovery observed downstream. The community at near-dam sites is largely composed of filter-feeding invertebrates which are quickly replaced downstream, while stoneflies are reduced below impoundments with limited downstream recovery. Despite a lack of formal testing, studies support SDC predictions. The SDC still provides a useful theoretical framework for hypothesis testing, and future studies should further expand the SDC to include empirical estimation within the context of the landscape.

scholarly journals Longitudinal ecological zonation in four Algerian streams

2018 ◽  
Vol 19 (2) ◽  
pp. 135-149
Author(s):  
Djamel Eddine Zouakh ◽  
◽  
Abderrafik Meddour ◽  
◽  
Keyword(s):  
Trophic Levels ◽  
Invertebrate Fauna ◽  
River Continuum ◽  
Site Distribution ◽  
Biological Survey ◽  
Continuum Concept ◽  
Middle Stream ◽  
Ecological Zonation ◽  
Downstream Area ◽  
Hydrographic Network

This hydro-biological survey on benthic invertebrates was carried out in the most important hydrographic network of the Mitidja plain,Oued El Harrachbasin, Algeria. Results revealedecological zonation taking into account the taxonomic richness and the relative abundance of different zoological groups, and allowed distinguishing abundant, ubiquitous and permanent taxa as well as the existence of a spatiotemporal faunistic gradient. These preliminary results allowed highlightingtaxonomically the “upstream invertebrate fauna”, the “ubiquitous invertebrate fauna” and the “downstream invertebrate fauna”. Consequently, it appearedthat Plecoptera, Hemiptera, Coleoptera are characteristic to the upstream area during the whole year in most of the sampling sites, whereas Diptera, Oligochaeta and Hydracarina are more abundant in the downstream area but in less density in the middle stream. On the other hand, the longitudinal evolution approach was considered in order to evaluate the inter-site distribution. According to the trophic levels, the classification between the various communities was investigated taking into account the concepts of the "Food Functional Group" and "The River Continuum Concept".

Tributaries, sediment sources, and the longitudinal organisation of macroinvertebrate fauna along river systems

2001 ◽  
Vol 58 (4) ◽  
pp. 824-840 ◽  
Author(s):  
S P Rice ◽  
M T Greenwood ◽  
C B Joyce
Keyword(s):  
Spatial Scales ◽  
River System ◽  
Water Volume ◽  
Physical Habitat ◽  
River Continuum ◽  
Regulated Rivers ◽  
New Model ◽  
Lotic Ecosystem ◽  
Continuum Concept ◽  
Stream Biota

Tributary confluences are sites along a main channel where, because of the introduction of water and (or) sediment, the water volume, bed sediment character, and water quality of the mainstream can change abruptly. These shifts ensure that abiotic gradients seldom vary smoothly or continuously for distances of more than 100–102 km along any river system. The ways in which tributaries and related sediment recruitment points structure longitudinal changes in physical habitat are examined. Variables of importance to stream biota are affected and, in turn, it is suggested that the arrangement of tributaries and related features is an important control on the longitudinal organisation of macroinvertebrate benthos at moderate spatial scales. A new model is presented that stresses the importance of hydrological and sedimentological networks for organising lotic fauna. The link discontinuity concept emphasises the discontinuous nature of lotic ecosystem gradients, addresses the importance of tributaries in unregulated as well as regulated rivers, and extends, to its logical conclusion, the limited recognition of tributary influence in the river continuum concept. A case study from British Columbia, Canada, illustrates the general merit of the new model.

A simulation tool for managing environmental flows in regulated rivers

2015 ◽  
Vol 73 ◽  
pp. 117-132 ◽  
Author(s):  
C.M.M. Steinfeld ◽  
R.T. Kingsford ◽  
E.C. Webster ◽  
A. Sharma
Keyword(s):  
Environmental Flows ◽  
Simulation Tool ◽  
Regulated Rivers

Modelling the economic impact of environmental flows for regulated rivers in New South Wales, Australia

2003 ◽  
Vol 48 (7) ◽  
pp. 157-164
Author(s):  
R.T. Jayasuriya
Keyword(s):  
Economic Impact ◽  
Environmental Flows ◽  
New South ◽  
New South Wales ◽  
Water Source ◽  
Regulated Rivers ◽  
Community Based ◽  
South Wales ◽  
Groundwater Aquifers

The management of water resources across Australia is undergoing fundamental reform in line with the priorities identified by the Council of Australian Governments (COAG) in 1994. This includes reforms to the specification of property rights, the way the resource is shared between the environment, irrigators and other users, charges for water use and the operational management of the river systems. In New South Wales (NSW), a series of water sharing plans (WSPs) is being developed for each water source in the State including regulated rivers, unregulated rivers and groundwater aquifers. These plans, which are the mechanisms by which COAG reforms are being implemented, are being developed by community-based water management committees (WMCs). The role of the WMCs is to develop a plan that achieves a balance between environmental, economic and social outcomes. NSW Agriculture has assisted a number of WMCs by quantifying the economic impact of proposed WSP options on the irrigation community. This paper outlines the approach taken by NSW Agriculture to quantifying economic impacts on irrigators in regulated catchments and provides results of case studies in the Lachlan River Catchment which is heavily developed for irrigation.

Australian waterbirds - time and space travellers in dynamic desert landscapes

2010 ◽  
Vol 61 (8) ◽  
pp. 875 ◽  
Author(s):  
R. T. Kingsford ◽  
D. A. Roshier ◽  
J. L. Porter
Keyword(s):  
Resource Availability ◽  
Environmental Flows ◽  
Anthropogenic Impacts ◽  
Aquatic Organisms ◽  
River Regulation ◽  
Population Declines ◽  
Time And Space ◽  
Regulated Rivers ◽  
Spatial And Temporal Scales ◽  
Resource Patches

Australia’s waterbirds are mostly nomadic, capitalising on highly variable aquatic resources in the arid interior (70% of the continent) for feeding and breeding. Waterbirds, unlike most aquatic organisms, can move between catchments, exploiting habitat wherever it occurs. In Australia, patterns of resource availability for waterbirds are mostly pulsed with peaks of productivity, coinciding with flooding and differing in time and space, affecting individuals, species and functional groups of waterbirds. Australian waterbirds are no different from waterbirds elsewhere, with their behaviour reflecting broad-scale resource availability. They respond to changing patterns of resource distribution, with rapid movements at spatial and temporal scales commensurate with the dynamics of the resource. The most serious conservation threat to waterbirds is a bottleneck in resource availability, leading to population declines, increasingly forced by anthropogenic impacts. River regulation and other threats (e.g. draining) reduce the availability of wetland habitat and decrease the probability of viable resource patches. It is axiomatic that waterbirds need water and such population bottlenecks may occur when the availability of water across the continent is limited. The rehabilitation of regulated rivers with environmental flows and protection of naturally flowing rivers in the arid region are essential for long-term sustainability of Australia’s waterbird populations.

Retesting a prediction of the River Continuum Concept: autochthonous versus allochthonous resources in the diets of invertebrates

2016 ◽  
Vol 35 (2) ◽  
pp. 534-543 ◽  
Author(s):  
Emma J. Rosi-Marshall ◽  
Kathryn L. Vallis ◽  
Colden V. Baxter ◽  
John M. Davis
Keyword(s):  
River Continuum Concept ◽  
River Continuum ◽  
Allochthonous Resources ◽  
Continuum Concept

Hydrologic and Riparian Influences on the Import and Storage of Coarse Particulate Organic Matter in a Prairie Stream

1988 ◽  
Vol 45 (4) ◽  
pp. 655-665 ◽  
Author(s):  
Martin E. Gurtz ◽  
G. Richard Marzolf ◽  
Keith T. Killingbeck ◽  
David L. Smith ◽  
J. Vaun McArthur
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Riparian Vegetation ◽  
River Continuum Concept ◽  
Hydrologic Regime ◽  
River Continuum ◽  
Coarse Particulate Organic Matter ◽  
Continuum Concept ◽  
And Storage ◽  
Prairie Stream

The hydrologic regime and zonation of riparian vegetation influenced the quantity and quality of coarse particulate organic matter (CPOM; >1 mm) stored in the channel and upper bank of a prairie stream. In a 5.4-km intermittent reach of the South Branch of Kings Creek on Konza Prairie, Kansas, total annual import was lowest in headwater reaches and increased downstream. Total storage of benthic CPOM in the dry channel and on the bank before the flow period was highest in the fourth- and fifth-order gallery forest zone (999 g ash-free dry mass∙m−2) and less in upstream reaches (320–341 g∙m−2). These longitudinal patterns of CPOM annual import and storage (before the flow period) were opposite those predicted by the river continuum concept for streams draining forested regions. Following flow, headwater channels had more CPOM (291 g∙m−2) than downstream reaches. On the bank, storage was always highest in downstream reaches. Composition of CPOM both in the channel and on the bank varied with changes in riparian vegetation; grass tissues dominated in headwater channels, while wood and leaves of trees and shrubs were more abundant downstream. During the flow period, storage of CPOM increased only in headwater channels, where retention was high despite the lack of woody debris. In this intermittent prairie stream, benthic CPOM may not contribute consistently to the terrestrial/aquatic linkages that are suggested in the river continuum concept because of (1) a paucity of large CPOM sources (e.g. trees, shrubs) in the upper reaches and (2) a hydrologic regime that reduces the amount, as well as the predictability, of stored CPOM. The biota of prairie streams must have opportunistic food gathering and reproductive strategies to take advantage of variable food resources in a flow environment that is itself very unpredictable.

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