scholarly journals Effects of Habitat Restoration on Fish Communities in Urban Streams

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2170
Author(s):  
Anna M. Lavelle ◽  
Michael A. Chadwick ◽  
Daniel D. A. Chadwick ◽  
Eleri G. Pritchard ◽  
Nicolas R. Bury

Geomorphological alterations, hydrological disconnectivity and water pollution are among the dominant pressures affecting ecological integrity in urban streams. River restoration approaches often involve utilising in-stream structures to encourage flow heterogeneity and promote habitat diversity. However, few studies examine the success of such projects. In this study, fish density, biomass and community structure at paired restored and unrestored reaches across five tributaries of the River Thames were examined. Fish density varied among rivers and reaches but was generally higher at restored sites. Restored sites also exhibited higher overall fish biomass, attributed mainly to the presence of brown trout (Salmo trutta L.) at the River Wandle. Despite higher density and biomass values at restored sites, the community structure analysis did not identify strong links between either river or restoration status using either species-specific density or biomass. Our results highlight that although reach-scale restoration can lead to localised increases in species density and biomass, this may chiefly be due to aggregation owing to preferential habitats created through restoration activities at these sites. Over larger spatial scales, significant improvements to species richness and diversity are likely to be limited due to the poor water quality and disconnected nature of these urban streams. Whilst reach-scale restoration clearly has the potential to provide preferential habitats for fish species, future efforts should focus on improving connectivity for fish across the wider Thames basin network by removing barriers to passage, improving water quality, restoring watershed processes and creating well-connected, diverse habitats which can facilitate the survival of a wide array of fish species throughout their life cycle.

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3155
Author(s):  
Shumin Liu ◽  
Fengbin Zhao ◽  
Xin Fang

Phytoplankton and bacterioplankton play a vital role in the structure and function of aquatic ecosystems, and their activity is closely linked to water eutrophication. However, few researchers have considered the temporal and spatial succession of phytoplankton and bacterioplankton, and their responses to environmental factors. The temporal and spatial succession of bacterioplankton and their ecological interaction with phytoplankton and water quality were analyzed using 16S rDNA high-throughput sequencing for their identification, and the functions of bacterioplankton were predicted. The results showed that the dominant classes of bacterioplankton in the Qingcaosha Reservoir were Gammaproteobacteria, Alphaproteobacteria, Actinomycetes, Acidimicrobiia, and Cyanobacteria. In addition, the Shannon diversity indexes were compared, and the results showed significant temporal differences based on monthly averaged value, although no significant spatial difference. The community structure was found to be mainly influenced by phytoplankton density and biomass, dissolved oxygen, and electrical conductivity. The presence of Pseudomonas and Legionella was positively correlated with that of Pseudanabaena sp., and Sphingomonas and Paragonimus with Melosira granulata. On the contrary, the presence of Planctomycetes was negatively correlated with Melosira granulata, as was Deinococcus-Thermus with Cyclotella sp. The relative abundance of denitrifying bacteria decreased from April to December, while the abundance of nitrogen-fixing bacteria increased. This study provides a scientific basis for understanding the ecological interactions between bacteria, algae, and water quality in reservoir ecosystems.


<em>Abstract</em>.—Three adjacent tidal creek systems (Page, Kemps, and Broad creeks) on Cape Eleuthera, The Bahamas were studied to quantify the variation in fish community structure and habitat characteristics over small (<5 km) spatial scales. Snorkeling transects were used to census the fish community on a summer new moon during slack high tide and involved the simultaneous assessment of each creek and each zone within the creek (i.e., mouth, middle, and upper) replicated over three consecutive days. The simultaneous assessment (involving large teams) was done to enable direct comparison without spatial sampling being confounded by time. Habitat assessments included measurements of water quality parameters, sediment sampling, and vegetation surveys. Despite their close proximity, creeks differed in both fish community structure and habitat characteristics. Broad Creek had the greatest fish species richness (<em>n </em>= 15), followed by Kemps Creek (<em>n </em>= 14) and Page Creek (<em>n </em>= 10). Mangrove habitats had significantly greater fish species diversity in Broad Creek while sea grass habitats resulted in higher species richness in Page Creek, relative to other habitat types. Mangrove and algal plain habitats had the highest fish species diversity in Kemps Creek. Within creeks, fish abundance was dependent on zonation, with the largest number of fish being found in creek mouths compared to upper sections. Water quality parameters (i.e., temperature, dissolved oxygen, and salinity) differed among the creeks, presumably reflecting creek morphology. Out of the 10 different species of vegetation observed, 60% were found in all tidal creeks. Coarse sand was the predominant particle size for all creeks, with variation in the second most abundant particle size between Page Creek and the others. This study reveals the great heterogeneity of tidal creek fish community and habitat characteristics and illustrates that conservation and management strategies along with monitoring programs must recognize the variation that can occur among and within coastal creeks over relatively small spatial scales.


2017 ◽  
Vol 41 (S1) ◽  
pp. 144-158 ◽  
Author(s):  
Richard G. Balouskus ◽  
Timothy E. Targett

Abstract Anthropogenic modifications of estuarine environments, including shoreline hardening and corresponding alteration of water quality, are accelerating worldwide as human population increases in coastal regions. Estuarine fish species inhabiting temperate ecosystems are adapted to extreme variations in environmental conditions including water temperature, salinity, and dissolved oxygen across seasonal, daily, and hourly time scales. The present research utilized quantitative sampling to examine the spatiotemporal distribution of shore-zone estuarine fish species in association with four unique shoreline types across a range of water temperature and dissolved oxygen conditions. Fish were collected from the intertidal and shallow subtidal region of four shoreline types, Spartina alterniflora marsh, Phragmites australis marsh, riprap, and bulkhead, in the summer and fall of 2009 and 2010. Analyses were performed to (1) compare mean fish density among shoreline types across all water conditions and (2) explore relationships of the complete fish assemblage, three functional species groupings, and two fish species (Fundulus heteroclitus and Menidia menidia) to unique shoreline/water conditions. Significantly greater mean fish densities were found along S. alterniflora shorelines than armored shorelines. Several metrics including fish density, species richness, and occurrence rates suggest S. alterniflora shorelines may serve as a form of refuge habitat during periods of low dissolved oxygen and high temperatures for various species, particularly littoral-demersal species including F. heteroclitus. Potential mechanisms that could contribute to a habitat providing refuge during adverse water quality conditions include tempering of the adverse condition (decreased temperatures, increased dissolved oxygen), predation protection, and increased foraging opportunities.


2021 ◽  
Vol 9 ◽  
Author(s):  
Damian H. Bubb ◽  
Kim Birnie-Gauvin ◽  
Jeroen S. Tummers ◽  
Kim Aarestrup ◽  
Niels Jepsen ◽  
...  

Barrier removal is increasingly being seen as the optimal solution to restore lotic habitat and fish communities, however, evidence of its efficacy is often limited to single sites or catchments. This study used a before–after methodology to examine the short-term (average, 541 days) effects of low-head (0.1–2.9 m) barrier removal at 22 sites distributed across Denmark and northern England on fish density, community, and river habitat responses. Following barrier removal, changes in the aquatic habitat were observed, such that the area immediately upstream of the former barrier location became shallower, with larger substrate and faster flow conditions. The reinstatement of this habitat was especially valuable in Danish streams, where these habitat features are rare, due to the naturally low gradients. Across all 22 sites fish species richness and diversity was similar before and after removal of barriers, likely because of the short study timescale (1–2 years). Across all sites combined, there was an increase in total fish density following barrier removal. A large increase in salmonid (Salmo trutta and Salmo salar) densities following barrier removal occurred at 7 out of 12 Danish sites. No similar response in salmonid density was observed at any of the UK sites which were mostly characterized by high channel gradients and short ponded zones. Two UK barrier removal sites showed marked increases in density of non-salmonid fish species. This study suggests that the removal of low-head barriers can be an effective method of restoring lotic habitats, and can lead to positive changes in fish density in the former ponded zone. The short-term effect of small barrier removal on the fish community is more variable and its effectiveness is likely to be determined by wider riverine processes.


1994 ◽  
Vol 29 (4) ◽  
pp. 599-617 ◽  
Author(s):  
Gordon A. Wichert

Abstract A weighted species association tolerance index with respect to water quality (WSATI-WQ) was crafted based on the literature on the sensitivity of different species to certain types of changes in their habitats. This index was used to compare changes through time in ecological conditions at locales in 12 subwatersheds in Toronto streams. As expected, WSATI-WQ scores were generally largest at relatively undisturbed sites and became progressively smaller with increasing deviation from an undisturbed state. Benefits from improved management of sewage have offset some of the degradation associated with earlier urbanization. It appears that modern urban stresses are less harmful to aquatic systems than were urban stresses of the past since some tolerant fish species presently live in urban streams where fish were absent 40 years ago.


2020 ◽  
Vol 640 ◽  
pp. 79-105
Author(s):  
ET Porter ◽  
E Robins ◽  
S Davis ◽  
R Lacouture ◽  
JC Cornwell

Anthropogenic disturbances in the Chesapeake Bay (USA) have depleted eastern oyster Crassostrea virginica abundance and altered the estuary’s environment and water quality. Efforts to rehabilitate oyster populations are underway; however, the effect of oyster biodeposits on water quality and plankton community structure are not clear. In July 2017, we used 6 shear turbulence resuspension mesocosms (STURMs) to determine differences in plankton composition with and without the daily addition of oyster biodeposits to a muddy sediment bottom. STURM systems had a volume-weighted root mean square turbulent velocity of 1.08 cm s-1, energy dissipation rate of ~0.08 cm2 s-3, and bottom shear stress of ~0.36-0.51 Pa during mixing-on periods during 4 wk of tidal resuspension. Phytoplankton increased their chlorophyll a content in their cells in response to low light in tanks with biodeposits. The diatom Skeletonema costatum bloomed and had significantly longer chains in tanks without biodeposits. These tanks also had significantly lower concentrations of total suspended solids, zooplankton carbon, and nitrite +nitrate, and higher phytoplankton carbon concentrations. Results suggest that the absence of biodeposit resuspension initiates nitrogen uptake for diatom reproduction, increasing the cell densities of S. costatum. The low abundance of the zooplankton population in non-biodeposit tanks suggests an inability of zooplankton to graze on S. costatum and negative effects of S. costatum on zooplankton. A high abundance of the copepod Acartia tonsa in biodeposit tanks may have reduced S. costatum chain length. Oyster biodeposit addition and resuspension efficiently transferred phytoplankton carbon to zooplankton carbon, thus supporting the food web in the estuary.


2013 ◽  
Vol 20 (1) ◽  
pp. 177-188
Author(s):  
Tangbin HUO ◽  
Zhe LI ◽  
Zuofa JIANG ◽  
Bo MA ◽  
Hongxian YU

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Łukasz Głowacki ◽  
Andrzej Kruk ◽  
Tadeusz Penczak

AbstractThe knowledge of biotic and abiotic drivers that put non-native invasive fishes at a disadvantage to native ones is necessary for suppressing invasions, but the knowledge is scarce, particularly when abiotic changes are fast. In this study, we increased this knowledge by an analysis of the biomass of most harmful Prussian carp Carassius gibelio in a river reviving from biological degradation. The species' invasion followed by the invasion's reversal occurred over only two decades and were documented by frequent monitoring of fish biomass and water quality. An initial moderate improvement in water quality was an environmental filter that enabled Prussian carp’s invasion but prevented the expansion of other species. A later substantial improvement stimulated native species’ colonization of the river, and made one rheophil, ide Leuciscus idus, a significant Prussian carp’s replacer. The redundancy analysis (RDA) of the dependence of changes in the biomass of fish species on water quality factors indicated that Prussian carp and ide responded in a significantly opposite way to changes in water quality in the river over the study period. However, the dependence of Prussian carp biomass on ide biomass, as indicated by regression analysis and analysis of species traits, suggests that the ecomorphological similarity of both species might have produced interference competition that contributed to Prussian carp’s decline.


2021 ◽  
Vol 13 (5) ◽  
pp. 2486
Author(s):  
Jong-Yun Choi ◽  
Seong-Ki Kim

Empirical studies suggest that changes in the density of top predators, such as carnivorous fish, in freshwater food webs, strongly affect not only fish communities but also various primary and secondary consumers. Based on these findings, we explored how differences in the utilization of carnivorous fish (i.e., Northern Snakehead, Channa argus) by humans affected the fish and cladoceran community structure as well as the settlement of exotic fish species (i.e., Lepomis macrochirus and Micropterus salmoides) in 30 wetlands located in the upper and lower reaches of the Nakdong River. Our results show that in the mid–lower reaches of the Nakdong River, the density of C. argus was low, while high densities of L. macrochirus and M. salmoides were observed. Exotic fish species are frequently consumed by C. argus, leading to a low density of L. macrochirus and M. salmoides in the upper reaches, which supported a high density of C. argus. However, in the mid–lower reaches, the density of L. macrochirus was high because of the frequent collection of C. argus by fishing activities. The dominance of L. macrochirus significantly changed the structure of cladoceran communities. L. macrochirus mainly feeds on pelagic species, increasing the density of epiphytic species in the mid–lower reaches. The continued utilization of C. argus by humans induced a stable settlement of exotic fish species and strongly affected the community structures of primary consumers in the 30 wetlands. The frequency of C. argus collection has to be reduced to secure biodiversity in the mid–lower reaches of the Nakdong River, which will reduce the proportion of exotic fish species and increase the conservation of native fish.


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