Effects of Urbanization on Stream Ecosystems

2005 ◽  
Keyword(s):  
Species Composition ◽  
Flow Regime ◽  
Algal Biomass ◽  
Urban Streams ◽  
Physical Habitat ◽  
Assemblage Composition ◽  
Consistent Manner ◽  
Algal Assemblages ◽  
Lake City ◽  
Fish Grazing

<em>Abstract.</em>—Patterns of stream benthic algal assemblages along urbanization gradients were investigated in three metropolitan areas—Boston (BOS), Massachusetts; Birmingham (BIR), Alabama; and Salt Lake City (SLC), Utah. An index of urban intensity derived from socioeconomic, infrastructure, and land-use characteristics was used as a measure of urbanization. Of the various attributes of the algal assemblages, species composition changed along gradients of urban intensity in a more consistent manner than biomass or diversity. In urban streams, the relative abundance of pollutiontolerant species was often higher than in less affected streams. Shifts in assemblage composition were associated primarily with increased levels of conductivity, nutrients, and alterations in physical habitat. Water mineralization and nutrients were the most important determinants of assemblage composition in the BOS and SLC study areas; flow regime and grazers were key factors in the BIR study area. Species composition of algal assemblages differed significantly among geographic regions, and no particular algal taxa were found to be universal indicators of urbanization. Patterns in algal biomass and diversity along urban gradients varied among study areas, depending on local environmental conditions and habitat alteration. Biomass and diversity increased with urbanization in the BOS area, apparently because of increased nutrients, light, and flow stability in urban streams, which often are regulated by dams. Biomass and diversity decreased with urbanization in the BIR study area because of intensive fish grazing and less stable flow regime. In the SLC study area, correlations between algal biomass, diversity, and urban intensity were positive but weak. Thus, algal responses to urbanization differed considerably among the three study areas. We concluded that the wide range of responses of benthic algae to urbanization implied that tools for stream bioassessment must be region specific.

The effects of water-level changes on periphytic algal assemblages in Poyang Lake

2020 ◽  
Author(s):  
Kuimei Qian ◽  
Martin Dokulil ◽  
Wan Lei ◽  
Yuwei Chen
Keyword(s):  
Water Level ◽  
Algal Biomass ◽  
Environmental Changes ◽  
Poyang Lake ◽  
Temporal Variations ◽  
Algal Community ◽  
Temperature Conductivity ◽  
Periphytic Algae ◽  
Water Level Changes ◽  
Algal Assemblages

Poyang Lake, which is the largest freshwater lake in China, has a seasonal flooding cycle that significantlychanges the water level every year. The aim of this study was to research the effects of water-level changeson periphytic algal assemblages in Poyang Lake. Dynamic shift of periphytic algal biomass were studied fromNovember 2016 to July 2019. Periphytic algal biomass and species composition were analyzed microscopically, andphysicochemical conditions were measured. There were significant seasonal variations in the community distributionof periphytic algae. The biomass of the periphyton ranged from 8 to 22,636 mg m-2. Periphytic algal biomassranged from 30 to 622 mg m-2 with the average of 204 mg m-2 in the LWL phase; periphytic algal biomass rangedfrom 8 to 21,839 mg m-2, with the average of 3,399 mg m-2 in the IWL phase. It ranged from 166 to 22,636 mgm-2, with the average 4,320 mg m-2 in the HWL phase and from 16 to 3,231 mg m-2 with the average of 585 mgm-2 in the DWL phase. There were temporal variations in periphytic algal community structure in Poyang Lake.Cryptophyceae dominated in algal periphyton from November 2016 to February 2017. Bacillariophyceae dominatedfrom March to July 2017 (increasing water-level phases). Pyrrophyceae and Euglenophyceae were dominant fromAugust and September (high-water-level phase) in 2017. Bacillariophyceae dominated through 2018 with occasionaldominance of Cryptophyceae from January to June and the occasional dominance of Chlorophyceae fromJuly to December. Chlorophyceae dominated from January to July in 2019 with occasional dominance of Bacillariophyceae.The water-level variations led to environmental heterogeneity in Poyang Lake, creating heterogeneoushabitats for algal periphyton. Our study revealed the primary importance of water level, water temperature, conductivity,total nitrogen, nitrite and total phosphorus as abiotic local factors structuring the periphytic algal communityin Poyang Lake. The water-level changes did not prevent growth of periphytic algae, but it did change the periphyticalgal community assemblages. This research provides data on the periphytic algae in Poyang Lake and will beuseful for establishing biological indicators of environmental changes and protecting Poyang Lake in the future.

Can Post-Oil Spill Patterns of Change be Used to Infer Recovery?

1999 ◽  
Vol 1999 (1) ◽  
pp. 339-347
Author(s):  
Scott Kimura ◽  
John Steinbeck
Keyword(s):  
High Pressure ◽  
Species Composition ◽  
Study Design ◽  
Oil Spill ◽  
Natural Variation ◽  
Oil Spills ◽  
Hot Water ◽  
Biological Communities ◽  
Recovery Processes ◽  
Algal Assemblages

ABSTRACT Assessing recovery from oil spills in areas not previously studied must be based on comparisons of changes in affected areas to changes in unaffected areas. The present study on impacts and recovery in intertidal biological communities affected by the Exxon Valdez oil spill in Prince William Sound, Alaska, began after the spill. The study was designed to contrast recovery processes of two types of oiled stations: (1) stations that were treated with hot water delivered at high pressure to remove oil from the shorelines, and (2) untreated stations. Natural variation in species composition and abundance was concurrently monitored at unoiled stations. Correspondence analyses of data collected at rocky mid-intertidal stations from 1989 to 1997 show that unoiled algal assemblages remained relatively unchanged. Algal assemblages at treated and untreated oiled stations returned to patterns of species composition and abundance similar to those at unoiled stations. The convergence of patterns provides evidence of recovery. In contrast, changes in invertebrate abundances were characterized by high year-to-year variation that exceeded within year differences among oiled and unoiled stations. Convergence of patterns was not clearly evident in the analysis, and any recovery in the invertebrates can only be based on the fact that variations observed at the oiled stations appeared as great as natural variation. These results indicate that recovery for some species can be assessed when post-spill monitoring occurs for a sufficient length of time, but is also dependent on characteristics of the study design.

scholarly journals Algal community composition within territories of the damselfish Stegastes nigricans (Pomacentridae, Labroidei) in Fiji and the Cook Islands

2005 ◽  
Vol 23 (1) ◽  
pp. 43 ◽  
Author(s):  
L W Zemke-White ◽  
E L Beatson
Keyword(s):  
Species Composition ◽  
Community Composition ◽  
Algal Species ◽  
Abundant Species ◽  
Red Alga ◽  
Algal Community ◽  
Filamentous Algae ◽  
Cook Islands ◽  
Algal Assemblages

The species composition of algal assemblages inside territories of the damselfish Stegastes nigricans was examined from Nananu-i-ra Island, Fiji and Rarotonga, Cook Islands. A total of 32 algal species were identified, the majority of them Rhodophytes (24 species). Seven species were unique to Rarotonga, six were unique to Fiji, with the remaining 19 species recorded at both locations. The biodiversity of territories was similar at both locations. The red alga, Herposiphonia secunda, was the most abundant species found, comprising 40.33% � 3.51SE and 33.94% � 3.58SE from Rarotonga and Fiji respectively. Gelidiopsis intricata, Polysiphonia sp., Aglaothamnion cordatum, and various Cyanophytes were also abundant at both locations. As a group, filamentous algae accounted for 70.35% of the algae found within the territories at all sites. We suggest that if S. nigricans are actively weeding their territories, they are selecting filamentous algae, and particularly Herposiphonia sp. and Polysiphonia sp.

From continua to patches: examining stream community structure over large environmental gradients

2002 ◽  
Vol 59 (8) ◽  
pp. 1404-1417 ◽  
Author(s):  
Kristopher K Wright ◽  
Judith L Li
Keyword(s):  
Conceptual Framework ◽  
Algal Biomass ◽  
Environmental Gradients ◽  
Spatial Scales ◽  
Habitat Characteristics ◽  
Physical Habitat ◽  
Macroinvertebrate Communities ◽  
Order Stream ◽  
Longitudinal Gradients ◽  
Individual Variables

We present an approach that integrates a conceptual framework with multivariate ordination techniques and traditional parametric analyses to examine biotic and abiotic gradients in stream ecosystems. Ordinations were used to examine multivariate patterns along an environmental gradient, with individual variables used to interpret those patterns across spatial scales. The conceptual framework provides a consistent context to compare community distributions and consequently allows for hypothesis testing using ordinations. To illustrate the approach, we examined the physical template, fish and benthic macroinvertebrate communities, and algal biomass and production along a 1st- through 5th-order stream gradient in eastern Oregon. We hypothesized that longitudinal distributions of physical habitat characteristics, fishes, macroinvertebrates, and periphyton would reflect highly variable, discontinuous gradients. Multivariate patterns were determined by rotating nonparametric ordinations to a common set of variables and comparing them to conceptual models of (i) an ideal continuum, (ii) a random distribution, and (iii) discrete patches. Physical habitat and fishes reflected strong longitudinal gradients, macroinvertebrates were the most patchy, and algal biomass and production were highly variable. Distributions of individual variables from site and stream-order perspectives revealed how different factors, potentially influencing stream communities, may be continuous or patchy depending on spatial scale.

Effects of Urbanization on Stream Ecosystems

2005 ◽  
Keyword(s):  
Land Use ◽  
Urban Areas ◽  
Scale Effects ◽  
Salt Lake ◽  
Land Use Changes ◽  
Physical Habitat ◽  
Intensity Index ◽  
Basin Scale ◽  
Scale Population ◽  
Lake City

<em>Abstract.</em>—Responses of invertebrate assemblages along gradients of urban intensity were examined in three metropolitan areas with contrasting climates and topography (Boston, Massachusetts; Birmingham, Alabama; Salt Lake City, Utah). Urban gradients were defined using an urban intensity index (UII) derived from basin-scale population, infrastructure, land-use, land-cover, and socioeconomic characteristics. Responses based on assemblage metrics, indices of biotic integrity (B-IBI), and ordinations were readily detected in all three urban areas and many responses could be accurately predicted simply using regional UIIs. Responses to UII were linear and did not indicate any initial resistance to urbanization. Richness metrics were better indicators of urbanization than were density metrics. Metrics that were good indicators were specific to each study except for a richnessbased tolerance metric (TOLr) and one B-IBI. Tolerances to urbanization were derived for 205 taxa. These tolerances differed among studies and with published tolerance values, but provided similar characterizations of site conditions. Basin-scale land-use changes were the most important variables for explaining invertebrate responses to urbanization. Some chemical and instream physical habitat variables were important in individual studies, but not among studies. Optimizing the study design to detect basin-scale effects may have reduced the ability to detect local-scale effects.

Spatial and temporal variation in species composition of ciliates communities (Alveolata, Ciliophora) from tropical urban and rural streams

2021 ◽  
Vol 57 ◽  
pp. 24
Author(s):  
Luiz Felipe Machado Velho ◽  
Suzana de Fátima Rodrigues de Castro ◽  
Fernando Miranda Lansac-Tôha ◽  
Bianca Ramos Meira ◽  
Felipe Rafael de Oliveira ◽  
...  
Keyword(s):  
Species Composition ◽  
Light Availability ◽  
Domestic Wastewater ◽  
Taxonomic Composition ◽  
Urban Streams ◽  
Organic Load ◽  
Spatial And Temporal Variation ◽  
Agricultural Activities ◽  
Spatial And Temporal Patterns ◽  
Rural And Urban

The aim of this study was to investigate the spatial and temporal patterns in species composition of ciliates, in rural streams, affected by agricultural activities, and urban streams, impacted by domestic wastewater. Samplings were taken in two different periods of the year, in the headwater, middle and mouth stretch of ten streams. We recorded 143 species of ciliates, distributed in 14 groups, standing out Hymenostomatia, Peritrichia and Hypotrichia. Our results showed significant spatial (between rural and urban streams) and, especially, temporal differences (between winter and summer periods) in the ciliates taxonomic composition. Such differences seem to be not related to the organic load that was quite similar among streams and periods sampled. Rather, the changes in ciliates composition are probably driving mainly by other enviromental variables such as resources, determined by the spatial diferences in light availability, and flow water velocity and discharge, which present high temporal dissimilarity.

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