A Test of the Serial Discontinuity Concept: Longitudinal Trends of Benthic Invertebrates in Regulated and Natural Rivers of Northern Canada

2014 ◽  
Vol 32 (3) ◽  
pp. 462-472 ◽  
Author(s):  
L. E. Ellis ◽  
N. E. Jones
Keyword(s):  
Benthic Invertebrates ◽  
Northern Canada ◽  
Serial Discontinuity Concept ◽  
Serial Discontinuity ◽  
Natural Rivers

Revisiting the serial discontinuity concept

2001 ◽  
Vol 17 (4-5) ◽  
pp. 303-310 ◽  
Author(s):  
Jack A. Stanford ◽  
J.V. Ward
Keyword(s):  
Serial Discontinuity Concept ◽  
Serial Discontinuity

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 Evaluation of the influences of dam release types, land use, and habitat affecting abundance, richness, diversity, and community structure of larval and juvenile fish

2019 ◽  
Vol 76 (8) ◽  
pp. 1388-1397 ◽  
Author(s):  
R. Daniel Hanks ◽  
Kyle J. Hartman
Keyword(s):  
Spatial Scales ◽  
Life Stage ◽  
Juvenile Fish ◽  
Early Life Stage ◽  
Systematic Evaluation ◽  
Rapid Changes ◽  
Serial Discontinuity Concept ◽  
Serial Discontinuity ◽  
Control Stream ◽  
Habitat Variables

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.

The effect of small reservoirs on chironomid diversity and trait composition in Savanna streams: evidence for Serial Discontinuity Concept

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

Carotenoids in lichens from Northern Canada

1993 ◽  
Vol 104 (7-8) ◽  
pp. 551-556
Author(s):  
B. Czeczuga ◽  
E. A. John
Keyword(s):  
Northern Canada
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