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".

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.

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.

scholarly journals Transport of biogenes in the Szeszupa fluvial-limnic system in the Suwalski Landscape Park

2013 ◽  
Vol 13 (1) ◽  
pp. 31-42
Author(s):  
Elżbieta Jekatierynczuk-Rudczyk
Keyword(s):  
Trophic State ◽  
Arable Land ◽  
Anthropogenic Activity ◽  
Lake Basin ◽  
Ecological State ◽  
Slight Effect ◽  
Summer Period ◽  
River Continuum ◽  
River Catchment ◽  
Continuum Concept

AbstractTransport of biogenic matter along the course of the Szeszupa River in the Suwalski Landscape Park (SLP) occurs in accordance with the river continuum concept. Only TP concentration decreases along the river’s course. TP and TOC concentrations classify the Szeszupa River to the moderate ecological state. The ecological state of three lakes (Linówek, Pogorzałek, and Perty) in the Szeszupa River catchment was estimated as very good. The remaining lakes, due to high TP concentrations, belong to the moderate state. The management of the catchment affects the amount of biogenic matter supplied to the Szeszupa River. The highest proportion of forests in the Jaczniówka River catchment clearly results in a decrease in the amount of biogenes in the river. The remaining partial catchments, with a higher proportion of arable land, meadows, and pastures, provide higher amounts of bioelements. The loads of bioelements stored in lakes in the summer period are determined by the size of the lakes (surface area of a lake and volume of water accumulated in the lake basin). This directly suggests a lack of anthropogenic activity in the catchments or the very slight effect of it on the lakes’ ecological and trophic state.

scholarly journals Testing the River Continuum Concept with geostatistical stream-network models

2019 ◽  
Vol 39 ◽  
pp. 100773 ◽  
Author(s):  
Stefano Larsen ◽  
Maria Cristina Bruno ◽  
Ian P. Vaughan ◽  
Guido Zolezzi
Keyword(s):  
Network Models ◽  
River Continuum Concept ◽  
River Continuum ◽  
Stream Network ◽  
Continuum Concept

Does the river continuum concept apply on a tropical island? Longitudinal variation in a Puerto Rican stream

2006 ◽  
Vol 63 (1) ◽  
pp. 134-152 ◽  
Author(s):  
Effie A Greathouse ◽  
Catherine M Pringle
Keyword(s):  
Puerto Rico ◽  
Fish Predation ◽  
Functional Feeding Groups ◽  
River Continuum Concept ◽  
Running Waters ◽  
River Continuum ◽  
Feeding Mode ◽  
Continuum Concept ◽  
Basal Resources ◽  
Stream Size

We examined whether a tropical stream in Puerto Rico matched predictions of the river continuum concept (RCC) for macroinvertebrate functional feeding groups (FFGs). Sampling sites for macroinvertebrates, basal resources, and fishes ranged from headwaters to within 2.5 km of the fourth-order estuary. In a comparison with a model temperate system in which RCC predictions generally held, we used catchment area as a measure of stream size to examine truncated RCC predictions (i.e., cut off to correspond to the largest stream size sampled in Puerto Rico). Despite dominance of generalist freshwater shrimps, which use more than one feeding mode, RCC predictions held for scrapers, shredders, and predators. Collector–filterers showed a trend opposite to that predicted by the RCC, but patterns in basal resources suggest that this is consistent with the central RCC theme: longitudinal distributions of FFGs follow longitudinal patterns in basal resources. Alternatively, the filterer pattern may be explained by fish predation affecting distributions of filter-feeding shrimp. Our results indicate that the RCC generally applies to running waters on tropical islands. However, additional theoretical and field studies across a broad array of stream types should examine whether the RCC needs to be refined to reflect the potential influence of top-down trophic controls on FFG distributions.

Analysis of Longitudinal Zonation and the River Continuum Concept in the Oldman–South Saskatchewan River System

1982 ◽  
Vol 39 (9) ◽  
pp. 1258-1266 ◽  
Author(s):  
Joseph M. Culp ◽  
Ronald W. Davies
Keyword(s):  
River System ◽  
Subalpine Forest ◽  
Functional Feeding Groups ◽  
River Continuum Concept ◽  
Macroinvertebrate Communities ◽  
Terrestrial Vegetation ◽  
River Continuum ◽  
Longitudinal Zonation ◽  
South Saskatchewan River ◽  
Continuum Concept

During the summer–fall periods, the benthic macroinvertebrate communities of the Oldman–South Saskatchewan River system demonstrated a longitudinal zonation related to the subalpine forest, fescue prairie, and mixed prairie terrestrial ecosystems through which it flows. This zonation was primarily attributable to significant downstream increases in periphyton biomass, plant nutrients, and water temperature. Zonation was reduced in the Sate winter–spring periods and absent in May, during spring runoff. Longitudinal trends in macroinvertebrate functional feeding groups generally followed the predictions of the river continuum concept, with trophic composition apparently more strongly affected by autotrophic processes in the summer, and heterotrophic processes in the winter. By combining the river continuum concept with a watershed classification system based on geology, climate, soil type, and terrestrial vegetation, we suggest that biological comparisons of longitudinal zonation are enhanced.Key words: longitudinal zonation, reciprocal average ordination, river continuum concept, functional groups

Questions and Comments on the River Continuum Concept

1985 ◽  
Vol 42 (5) ◽  
pp. 1038-1044 ◽  
Author(s):  
Bernhard Statzner ◽  
Bert Higler
Keyword(s):  
Environmental Variability ◽  
Theoretical Background ◽  
River Continuum Concept ◽  
Key Factors ◽  
River Continuum ◽  
Running Water ◽  
Current State ◽  
Biotic Diversity ◽  
Continuum Concept ◽  
Water Ecosystems

The River Continuum Concept (RCC) is a generalized conceptual framework for characterization of pristine running water ecosystems. Of the numerous tenets of the concept we particularly reevaluated the following: biological analogues of energy equilibrium and entropy in the physical system; maximization of energy consumption through continuous species replacement over a year; absence of succession in stream ecosystems, which can thus be viewed in a time-independent fashion; and maximization of biotic diversity in midreaches of streams as a result of the occurrence of highest environmental variability there together with spatial abundance shifts of insects, molluscs, and crustaceans. When emphasis is placed on rapid changes in the downstream hydraulics dependent on discharge and slope (both of which are expressed by stream order in the RCC and are key factors of the concept) and on results from tropical studies, some of these tenets are partly refuted or need extension. Some of them are in conflict with the current state of knowledge in other domains of stream ecology or are at least open to various interpretations. Therefore, we advocate modifications of the theoretical background of the RCC.

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