The serial discontinuity concept: Extending the model to floodplain rivers

1995 ◽  
Vol 10 (2-4) ◽  
pp. 159-168 ◽  
Author(s):  
J. V. Ward ◽  
J. A. Stanford
2001 ◽  
Vol 17 (4-5) ◽  
pp. 303-310 ◽  
Author(s):  
Jack A. Stanford ◽  
J.V. Ward

2013 ◽  
Vol 21 (3) ◽  
pp. 136-148 ◽  
Author(s):  
Lucy Eunsun Ellis ◽  
Nicholas Edward Jones

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.


2019 ◽  
Vol 76 (8) ◽  
pp. 1388-1397 ◽  
Author(s):  
R. Daniel Hanks ◽  
Kyle J. Hartman

We systematically evaluated the influence of dams on downstream aquatic habitat and early life stage (ELS) fish at two spatial scales from epilimnetic and hypolimnetic discharges and made comparisons with a control stream. ELS fish exhibited a general increase in abundance, richness, and Shannon diversity with increasing distance from dams in both epilimnetic and hypolimnetic release types. Nonmetric multidimensional scaling (NMDS) indicated larval and juvenile fish communities were structured differently between epilimnetic and hypolimnetic releases, and habitat variables structuring those communities were more variable in epilimnetic releases than in hypolimnetic releases. Rapid changes occurred within the first 1100 m reach and a second more gradual gradient extended beyond the 5100 m sample reach. Generally, our findings agreed with that of the Serial Discontinuity Concept (SDC), but we believe future studies should be explicit in the systematic evaluation of the SDC, and further studies are required to understand the two recovery gradients that exist below impoundments.


Hydrobiologia ◽  
2016 ◽  
Vol 793 (1) ◽  
pp. 109-119 ◽  
Author(s):  
Hugo Henrique Saulino ◽  
Luciene Aparecida Leite-Rossi ◽  
Susana Trivinho-Strixino

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Agata Keller ◽  
Somsubhra Chattopadhyay ◽  
Mikołaj Piniewski

Abstract Background Flow variability is considered a fundamental factor affecting riverine biota. Any alterations to flow regime can influence freshwater organisms, and this process is expected to change with the projected climate change. This systematic map, therefore, aims at investigating the impacts of natural (resulting from climatic variability), anthropogenic (resulting from direct human pressure), and climate change-induced flow variability on fish and macroinvertebrates of temperate floodplain rivers in Central and Western Europe. Particular focus will be placed on the effects of extreme low and high discharges. These rare events are known to regulate population size and taxonomic diversity. Methods All studies investigating the effects of flow variability on metrics concerning freshwater fish and macroinvertebrates will be considered in the map, particularly metrics such as: abundance, density, diversity, growth, migration, recruitment, reproduction, survival, or their substitutes, such as biomonitoring indices. Relevant flow variability will reflect (1) anthropogenic causes: dams, reservoirs, hydroelectric facilities, locks, levees, water abstraction, water diversion, land-use changes, road culverts; (2) natural causes: floods, droughts, seasonal changes; or (3) climate change. Geographically, the map will cover the ecoregion of Central and Western Europe, focusing on its major habitat type, namely “temperate floodplain rivers and wetlands”. The review will employ search engines and specialist websites, and cover primary and grey literature. No date, language, or document type restrictions will be applied in the search strategy. We expect the results to be primarily in English, although evidence (meeting all eligibility criteria) from other languages within the study area will also be included. We will also contact relevant stakeholders and announce an open call for additional information. Eligibility screening will be conducted at two levels: title and abstract, and full text. From eligible studies the following information will be extracted: the cause of flow variability, location, type of study, outcomes, etc. A searchable database containing extracted data will be developed and provided as supplementary material to the map report. The final narrative will describe the quantity and key characteristics of the available evidence, and identify knowledge gaps and knowledge clusters, i.e. subtopics sufficiently covered by existing studies allowing full systematic review and meta-analysis.


1999 ◽  
Vol 41 (2) ◽  
pp. 407-423 ◽  
Author(s):  
M. C. Thoms ◽  
R. W. Ogden ◽  
M. A. Reid

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