Effects of low-head barriers on stream fishes: taxonomic affiliations and morphological correlates of sensitive species

McLaughlin, Robert L.; Porto, Louise; Noakes, David L. G.; Baylis, Jeffrey R.; Carl, Leon M.; Dodd, Hope R.; Goldstein, Jon D.; Hayes, Daniel B.; Randall, Robert G.

doi:10.1139/f05-256

Cited by 68 publications

(51 citation statements)

References 42 publications

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“…A strong correlation exists between habitat variables and fish assemblages, which imply that fragmentation and modification of riverine habitat can have profound effects on biotic integrity (Dynesius and Nilsson, 1994;McLaughlin et al, 2006;Harford and McLaughlin, 2007). The protection and conservation, as well as restoration and management of running water environments, requires an exact knowledge of the ecological demands of the most important species in order to genuinely understand the influence of the habitat alterations at a local scale (Jungwirth et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

The impact of small physical obstacles on the structure of freshwater fish assemblages

Alexandre

Almeida

2009

River Research & Apps

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Many studies have assessed the effects of large dams on fishes but few have examined the effects of small obstacles. Fishes were sampled and environmental variables were characterized at 28 sites in two Iberian streams, 14 located immediately downstream, upstream and between five small obstacles at river Muge and 14 at river Erra, considered as the reference stream. Multivariate analysis indicated that habitat variables like current velocity and depth, but not physicochemistry, were mainly responsible for site groups' discrimination in both streams. The reference stream exhibited a longitudinal gradient of current velocity that, however, was not strong enough to cause significant changes in the fish assemblage's composition and structure. By successive and drastically repeating this gradient near each structure, the obstacles stream presented differences in fish fauna between the three site types. Lentic upstream sites presented higher density of limnophilic, omnivorous and exotic species, like gudgeon Gobio lozanoi, which are well adapted to this type of habitat. Downstream and between obstacles sites were characterized by the dominance of rheophilic and invertivorous taxa, especially barbel Luciobarbus bocagei. Richness metrics did not differ among site types, but diversity was higher in sites located between the obstacles away from its direct influence, where the habitat diversity was higher. Contrarily to upstream sites, downstream and between obstacles sites were similar in many of the studied features to the reference stream, implying that this type of structures cause a higher modification in the upstream fish community. This study suggests that the effects of small obstacles on habitat and fishes are similar, in some extent, to those reported for larger dams, providing important considerations for riverine ecosystem conservation efforts.

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Section: Discussionmentioning

confidence: 99%

The impact of small physical obstacles on the structure of freshwater fish assemblages

Alexandre

Almeida

2009

River Research & Apps

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“…Helfrich et al (1999) discovered that fish species traits (e.g., swimming ability) appeared to be related to low-head dam passage, and they observed the cumulative effect of multiple low-head dams on fish assemblages. However, McLaughlin et al (2006) revealed that taxonomic affiliation and swimming morphology were not useful for predicting sensitivity to barriers for fishes, while Santucci et al (2005) did not find the obvious evidence of cumulative effects of multiple low-head dams. Cummings (2004) examined the influence of local habitat, network-specific measures and low-head dam on the fish species richness in headwater streams.…”

Section: Introductionmentioning

confidence: 93%

Influences of low-head dams on the fish assemblages in the headwater streams of the Qingyi watershed, China

et al. 2012

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The influences of low-head dams on the fish assemblages were examined in this study, using fish data collected in six treatment and five reference sites at three low-head dams in the headwater streams of the Qingyi watershed, China. Comparing with those in the reference sites, local habitat variables were significantly altered by low-head dams in the treatment sites, involving wider channel (only in the impoundment area), deeper water and slower flow. Fish species richness varied significantly across seasons, not across site categories, suggesting that these low-head dams did not alter species richness. However, significant decreases in fish abundance and density were observed in the impoundment areas immediately upstream of dams, but not in the plunge areas downstream. Fish assemblage structures kept relative stability across seasons, and their significant difference between-site was only observed between the impoundment areas and the sites far from dams upstream. This variation in assemblage structures was due to the differing relative abundance of some cooccurring species; more lentic but less lotic fish was observed in the impoundment areas. The spatial and temporal patterns of fish assemblages were correlated with local habitat in this study area. Wetted width had negative correlation with fish species richness, abundance and density, respectively. Water temperature also positively affected species richness. In addition, wetted width, water depth, current velocity and substrate were the important habitat variables influencing assemblage structures. Our results suggested that, by modifying local habitat characteristics, low-head dams altered fish abundance and density in the impoundment areas immediately upstream of dam, not in the plunge areas immediately downstream, and thereby influenced fish assemblage structures in these stream segments.

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“…Although a great deal of attention has been given to analyzing the effects of individual barriers, especially on fish, (e.g., Jungwirth et al 1998;Peter 1998;McLaughlin et al 2006), 85 surprisingly little attention has been given to the cumulative effect of barriers at the scale of river drainage networkriver networks. Methods to measure effects of multiple barriers at the extent of the entire landscape are in their infancy considered ; (Beechie et al 1994;Wheeler et al 2005).…”

Section: Introductionmentioning

confidence: 99%

A new measure of longitudinal connectivity for stream networks

Côté¹,

et al. 2008

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Habitat connectivity is a central factor in shaping aquatic biological communities, but few tools exist to describe and quantify this attribute at a network scale in riverine systems. Here, we develop a new index to quantify longitudinal connectivity of river networks based on the expected probability of an organism being able to move freely between two random points of the network.We apply this index to two fish life histories and evaluate the effects of the number, passability, and placement of barriers on river network connectivity through the use of simulated dendritic ecological networks. We then extend the index to a real world dendritic river system in Newfoundland, Canada.Our results indicate that connectivity in river systems, as represented by our index, is most impacted by the first few barriers added to the system. This is in contrast to terrestrial systems, which are more resilient to low levels of connectivity. The results show a curvilinear relationship between barrier passability and structural connectivity. This suggests that an incremental improvement in passability would result in a greater improvement to river network connectivity for more permeable barriers than for less permeable barriers. Our analysis of the index in simulated and real river networks also showed that barrier placement played an important role in connectivity.Not surprisingly, barriers located near the river mouth have the greatest impact on fish with diadromous life histories while those located near the center of the river network have the most impact on fish with potadromous life histories. The proposed index is conceptually simple and sufficiently flexible to deal with variations in river structure and biological communities. The index will enable researchers to account for connectivity in habitat studies and will also allow resource managers to characterize watersheds, assess cumulative impacts of multiple barriers and determine priorities for restoration.Response to Reviewers: July 21, 2008 To the Editor of Landscape Ecology, Thank you for your thorough review of our manuscript "A riverscape connectivity index" (LAND-08-1528R1). We have addressed each criticism and comment (see indented comments added to the LE decision letter below). In particular we have significantly shortened the introduction, replaced the simulated single channel system with that of a dendritic, added a conceptual cartoon and have Thank you for your submission to Landscape Ecology. Your paper has been recommended for publication with revisions. The reviews were all positive-each indicating that the connnectivity index is a valuable contribution to the aquatic landscape ecology literature. All of the reviewers suggest, and I concur that the manuscript is far too long, and thus, your major task in the revision will be to reduce the length substantially. The second issue, again raised by Reviewer # 1 is to address the issue of travel distance versus stream length. That reviewer presents a logical arguement that these two measures are no...

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Effects of low-head barriers on stream fishes: taxonomic affiliations and morphological correlates of sensitive species

Cited by 68 publications

References 42 publications

The impact of small physical obstacles on the structure of freshwater fish assemblages

The impact of small physical obstacles on the structure of freshwater fish assemblages

Influences of low-head dams on the fish assemblages in the headwater streams of the Qingyi watershed, China

A new measure of longitudinal connectivity for stream networks

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