Use of Community Data to Diagnose the Causes of Stream Impairment I Posters
Presiding: M Paul, Howard University; S Norton, U.S. Environmental Protection Agency; J Gerritsen, Tetra Tech, Inc.
NB33T-01 1330h
Storm Event and Multipoint Longitudinal Sampling with Biomonitored Responses to Turbidity in a NE Arkansas River
A two part monitoring scheme consisting of both single point storm event sampling and multipoint longitudinal sampling was developed and implemented for the characterization of turbidity in the L'Anguille River in Northeast Arkansas. For the single point storm event monitoring, temperature, conductivity, turbidity and river stage near Palestine, Arkansas, have been continuously measured and recorded at fifteen minute intervals from September 2003 to present. Water samples were collected for the determination of total suspended solids and nutrient levels via an automated sampler following three storm events that caused significant increases in river stage. Grab samples were collected bimonthly for the estimation of background sediment and nutrient loads related to increased turbidity and suspended sediments following storm events. In addition to the intensive single point monitoring, the sampling of additional reaches has been included to characterize conditions along the entire river that differed notably in turbidity and nutrient loads between river segments (100% and 75% respectively). Toxicity testing on collected water (both background and storm) using Ceriodaphnia dubia and Pimephales promelas has shown no significant impairment, while impaired survival has been observed using Chironomus tentans in collected streambed sediments.
NB33T-02 1330h
Use of Benthic Macroinvertebrates to Evaluate Stream Water Quality in Trinidad and Tobago, West Indies
In order to determine the best method of using benthic macroinvertebrates to monitor water quality in Trinidad and Tobago, 63 sites along 38 streams were sampled in each of the wet and dry seasons from 1999-2001. At each site, 5 benthic samples were collected with a 300Μm 'D' frame kicknet, along with data for 14 environmental parameters and habitat data. Principal Components Analyses separated the streams into 3 ecoregions based on substrate type and discharge. Using ANOVA, mean values for each environmental parameter were compared across each ecoregion. Values of dissolved Oxygen, BOD-5, nitrates, total suspended solids and pH varied significantly during the wet season, while dissolved Oxygen, pH and chlorophyll-a varied significantly during the dry. Using PRIMER version 5, non-metric multi-dimensional scaling and cluster analyses were performed on the faunal data for each ecoregion separately and for all sites combined. These analyses indicate that the fauna associated with minimally, moderately and severely impaired sites is similar across all 3 ecoregions. Of the different metrics compared during the study, a modified version of the Average Score Per Taxon (ASPT) best fit the clusters were produced.
NB33T-03 1330h
Site Dependent Beneficial Effects of Aquaculture Effluent
The effect of aquaculture effluent on community structure was examined in a stream formed by the discharge of treated acid mine water. The mine water stream and the raceway stream whose source was treated mine water were sampled. In addition, a site below the confluence of the mine water and raceway streams was also sampled. Initially, there were no significant differences in macroinvertebrate density, diversity or community structure in the closed canopy, low light, mine water and raceway streams. However, in the high light environment below the confluence, the community included a substantial proportion of grazers and density was significantly lower. After an inadvertent resuspension of precipitated metal hydroxides from the AMD treatment facility, communities in the mine water stream and below the confluence were strongly dominated by chironomids while the raceway stream maintained much of its diversity. At the end of the study period diversity in all streams was significantly greater than in earlier samples however, densities were 6-8x lower than initial values in the raceway and mine water streams. This study demonstrated that there was little effect of aquaculture effluent on the benthic community in a low-light environment. Additionally, aquaculture effluent mediated the negative effects of AMD metals.
NB33T-04 1330h
Icelandic River Communities: Ecological Classification and Anthropogenic Impact
There is no abstract associated with this presentation.
NB33T-05 1330h
Macroinvertebrate Community Responses to High and Low Flow Events in Streams Using the Benthic in situ Toxicity Identification Evaluation (BiTIE) Chamber
We developed a benthic in situ TIE (BiTIE) method for both indigenous and surrogate species in either water-only, or natural substrate filled chambers. The BiTIE's have shown stressor-response relationships during high and low flows in streams using single species. The BiTIE chamber system identifies the most toxic chemical class of compounds in water column exposures, and the differing treatments include resins which remove ammonia and non-polar organics. Additional testing evaluated macroinvertebrate community responses to high and low events. Macroinvertebrate communities were collected and transplanted at two sites in southwest Ohio (Honey Creek and Little Beavercreek) and evaluated after a 96 h exposure. The test sites were characterized using an array of macroinvertebrate community metrics. Chamber flow rates, water quality parameters, and resin (zeolite) saturation characteristics were examined during exposures. Resin treatments showed trends using % Ephemeroptera, % Trichoptera, % EPT, number of EPT, % clingers and % filters indicating chemical class presence, during both high and low flows. Mean flow rates inside chambers were 3.9 cm/s versus ambient conditions of 37.6 cm/s. Further research still exists for the BiTIE system, but the chamber appears to be versatile and capable of separating the dominant chemical classes in streams.
NB33T-06 1330h
Quantifying the Impacts of Forest Harvesting on Benthic Macroinvertebrate Community Structure in Western Canada
Benthic macroinvertebrates can be excellent indicators of stream condition and have been used to effectively assess stream health in disturbed watersheds. Previous works have demonstrated that community composition and density are significantly and predictably altered by disturbance. This study quantifies the impacts of forest harvesting on invertebrate community structure in headwater streams of west-central Alberta, Canada, using both parametric statistical techniques and a multimetric index. Invertebrates were sampled from six streams, three of which were harvested and three of which were undisturbed, in the summer of 2004. Preliminary analyses suggest that forest harvesting does not have a significant effect on benthic macroinvertebrate community structure, although relative densities of component groups may be altered. To date, stream monitoring programs in this region have focused primarily on physical habitat and water chemistry. However, our results demonstrate that the examination and inclusion of these biological measures may offer a new and wider perspective to stream monitoring and sustainable forestry programs.
NB33T-07 1330h
Are preiphyton communities useful for biomonitoring in the Fraser River, British Columbia, Canada?
To investigate the relationship between benthic algal communities and environmental variables, we sampled periphyton communities at 248 sites (198 reference and 50 disturbed) in the Fraser River, British Columbia, Canada between 1994 and 1996. 121 species (61 genera) were collected, of which 81 species (32 genera) were diatoms, indicating that the Fraser River may be depauperate relative to other temperate rivers. Communities at disturbed and reference sites were weakly but significantly different. Cluster analysis identified 5 groups, one of which contained most (60%) of the disturbed sites; however, all groups were dominated by reference sites (66-95%). All replicates of sites were assigned to the same group 65% of the time. NMS ordination showed that disturbance had only a weak relationship to community structure; many water column variables (TKN, suspended C, suspended N, alkalinity, conductivity, total phosphorous, chlorophyll a) showed stronger relationships. These results indicate that periphyton communities may have limited use for biomonitoring in the Fraser River because of low diversity, small differences between disturbed and undisturbed communities, and weak relationship to variables useful in modeling habitat relationships.
NB33T-08 1330h
Natural and Anthropogenic Factors Affecting Benthic Macroinvertebrate Communities in Streams Across an Urban Gradient in the San Francisco Bay Area, California, USA
The development of biological criteria for streams requires an understanding of how both natural environmental factors and human disturbance affect biological communities. We used biological metrics, species traits, and multivariate ordinations to assess the relative importance of natural and anthropogenic factors on stream benthic macroinvertebrate communities in the San Francisco Bay Area, California. Upstream watershed land use was the dominant factor affecting macroinvertebrate assemblages. Urban sites exhibited uniformly low richness and functional diversity, and were dominated by four taxa: Chironomidae, Baetis sp., Simulium sp., and Oligochaeta. In contrast, the majority of sites draining rural residential land uses were compositionally similar to minimally disturbed conditions, while sites draining agricultural lands reflected an intermediate level of disturbance. Flow intermittency was the most important natural factor affecting the composition of benthic assemblages. Taxa richness was significantly lower in minimally disturbed intermittent streams (32) than perennial streams (46), as a result of the near absence of taxa with aquatic adult life stages and long life cycles, other than the hellgrammite Neohermes filicornis that survives for months in the moist streambed. Although flow intermittency is a critical factor influencing stream communities in mediterranean climates, urban land use has a much greater effect on benthic assemblages.
NB33T-09 1330h
Habitat Variation in Wetland Invertebrate Communities With Varying Mosquito Larviciding Strategies
Monitoring, surveillance, and vector control of West Nile virus have received much attention and public resources in North America following the occurrence of human cases in 1999. With increased frequency of mosquito prevention and control programs, investigation of long-term ecological effects of larvicides used on wetland invertebrate communities is necessary. Before these effects can be examined, the variation among ponds and wetlands in features other than larviciding history needs to be examined. In a study on Bacillus thuringienisis israelensis (Bti), in the Township of East Gwillimbury and surrounding area, located in Southern Ontario, Canada, 18 wetlands were repeatedly sampled over a 5 month period. Physical habitat features, water chemistry (i.e. temperature, pH, conductivity, and dissolved oxygen), and metal and ion concentrations were measured and Principal Component Analysis was used to determine how ecosystem descriptors varied and covaried among ponds. Results showed sites with high sodium and chloride concentrations were positively correlated with both submerged and herbaceous plants in sandy environments and relatively high pHs. Based on these results, we predict weak effects of larvicide treatment on pond invertebrate communities relative to other natural and anthropogenic factors.
NB33T-10 1330h
Exploring Metrics in the 4th Dimension: Temporal Variability in Lotic Macroinvertebrate Community Structure
Many benthic macroinvertebrate biological monitoring programs typically sample once or twice a year. Community measurements, known as metrics, are used as a means of making comparisons between sites. However, metrics used in making assessments at localities are often calibrated within a general period of time that may span weeks or even months. Considering the expeditious nature of insect life-cycles, many metrics may be subject to considerable temporal variability. Macroinvertebrates were sampled on 10 relatively equally spaced dates throughout a year at a reference stream in central Missouri. The coefficient of variation (CV) showed that some metrics were subject to more temporal variability than were others. The Biotic Index was the lowest (CV = 11.43) whereas the ratio of shredders to total was the highest (CV = 160.48). Temporal patterns in community structure were examined.