EPT Taxa Research Articles

Response of benthic macroinvertebrate communities to highway construction in an Appalachian watershed

Highway construction in mountainous areas can result in sedimentation of streams, negatively impacting stream habitat, water quality, and biotic communities. We assessed the impacts of construction of a segment of Corridor H, a four-lane highway, in the Lost River watershed, West Virginia, by monitoring benthic macroinvertebrate communities and water quality, before, during, and after highway construction and prior to highway use at upstream and downstream sites from 1997 through 2007. Data analysis of temporal impacts of highway construction followed a Before-After-Control-Impact (BACI) study design. Highway construction impacts included an increase in stream sedimentation during the construction phase. This was indicated by an increase in turbidity and total suspended solids. Benthic macroinvertebrate metrics indicated a community more tolerant during and after construction than in the period before construction. The percent of Chironomidae and the Hilsenhoff Biotic Index (HBI) increased, while percent of Ephemeroptera, Plecoptera, and Trichoptera (EPT) decreased. Our 10-year study addressed short-term impacts of highway construction and found that impacts were relatively minimal. A recovery of the number of EPT taxa collected after construction indicated that the benthic macroinvertebrate community may be recovering from impacts of highway construction. However, this study only addressed a period of 3 years before, 3 years during, and 4 years post construction. Inferences cannot be made concerning the long-term impacts of the highway, highway traffic, runoff, and other factors associated with highway use. Continual monitoring of the watershed is necessary to determine if the highway has a continual impact on stream habitat, water quality, and biotic integrity.

Benthic macroinvertebrate communities in agriculturally impaired streams.

Normal 0 false false false EN-US X-NONE X-NONE This work presents research into the taxonomic composition of macroinvertebrate communities in streams that are under the influence of agricultural pollution A total of 67 macroinvertebrate taxa (including 61 identified species) belonging to 40 families have been identified in the explored streams. The greatest species richness is recorded for the Trichoptera (18 species/1 taxa) and Mollusca (12 species). The molluscs Gyraulus albus, amphipods Gammarus pulex, caddisflies Hydropsyche pellucidula and oligochaetes are detected in all examined streams. There, the number of total benthic macroinvertebrate taxa is highly variable, ranging from 16 to 40. Results show that the examined streams depending on the benthic macroinvertebrate taxonomic composition and predominance of seperate macroinvertebrate groups undergo different pollution. Intolerant to pollution taxa such as Plecoptera, which are the most sensitive to pollution insects, have been found only in 5 of 12 examined streams and in low abundances. The richness and diversity of macrozoobenthos in some streams appear to respond to the water quality deterioration. The present study has found out that in the stream where the total macroinvertebrate taxa, EPT taxa richness are the lowest and a relative abundance of gatherers is the highest, the values of NH 4 -N, NO 3 -N, total N, PO 4 -P and total P in the stream water are the highest, too.

Long-term historical analysis of benthic communities and physical habitat in an agricultural stream in California's San Joaquin River watershed

This study was designed to characterize long-term annual temporal and spatial trends (2001 to 2007) in physical habitat and benthic communities and to determine relationships of habitat and benthic communities during this 7-year period in an agricultural stream in the San Joaquin River watershed in California (Del Puerto Creek). The canonical discriminant analysis indicated that there were no overall significant temporal patterns for the habitat metrics although spatial patterns were prominent for nearly all the habitat metrics. Channel alteration, riparian vegetative zone, bank stability, vegetative protection and frequency of riffles/bends were the primary habitat metrics associated with these site effects. Approximately 3,700 to 4,500 individual macroinvertebrates were picked and identified from five Del Puerto Creek sites sampled annually from 2001 to 2007. The total number of taxa by year ranged from 81 in 2003 to 106 in 2007. These benthic assemblages were generally comprised of tolerant to moderately tolerant taxa such as blackflies, oligochaetes, snails and chironomids. The metrics % predators, % EPT index, % collectors/filterers and % shredders were the benthic metrics that were most associated with the temporal effects. Ephemeroptera taxa, trichoptera taxa, and % sensitive EPT index were the benthic metrics that were most associated with the site effects. The most upstream site in Del Puerto Creek had the most robust and healthy benthic communites. Strong statistical relationships were reported between certain benthic metrics and habitat metrics. Overall, samples taken from site-year combinations with sediments that were qualitatively less muddy (less fines) and that had higher habitat metric scores for embeddedness, riparian vegetative zone, and channel alteration tended to have benthic communities characterized by higher values of the benthic metrics such as EPT taxa, Ephemeroptera taxa, EPT index, abundance, and taxonomic richness, among others. Conversely, tolerance value and % tolerant taxa, the indicators of stressed benthic communities, were found to be inversely related to Bank Stability and Riparian vegetative zone (respectively), both indicators of habitat quality. Relationships between the quality of the physical habitat and the health of the benthic communities in aquatic systems, such as agricultural streams, needs to be considered before the impact of anthropogenic agents (e.g., pesticides, metals, and other potential toxicants) or other man-made perturbations may be understood. Otherwise, the interpretation of patterns of environmental conditions or causalities may be confounded.

Responses of Aquatic Macroinvertebrates to Stream Channel Reconstruction in a Degraded Rangeland Creek in the Sierra Nevada

Streams on western rangelands are sometimes degraded to the point that reestablishing lost ecological values requires rebuilding their physical structure, shape, and form. We evaluated the biological response to reconstruction of a small rangeland stream channel through comparisons of aquatic invertebrate communities before and after engineering activities and in relation to local and regional reference stream conditions. We measured geomorphic and riparian habitat features along with benthic macroinvertebrates for two years prior to restoration actions and for two years afterward. Stream restoration activities included the construction of a new channel to replace an incised meadow stream reach (including addition of coarse rock substrate, erosion control fabric, and willow planting) and the rehabilitation of gullies and roads in the meadow and its watershed. In postproject monitoring, we found statistically significant changes in the macroinvertebrate community and trophic structure at the restored site. These were exhibited as increases in EPT taxa (mayflies, stoneflies, caddisflies) and the proportion and diversity of sensitive taxa, decreased tolerant taxa, and an increase in consumers of riparian organic matter (shredders) and decrease in fine organic particle filter-feeders. A site monitored downstream of the restoration activities exhibited increased deposition of fines and sand one year after project construction, but was similar to preproject conditions in the second year, and the macroinvertebrate community was unchanged. Improved biological integrity at the restored site showed that rapid recovery can occur in rebuilt streams within rehabilitated watersheds, but neither degraded nor enhanced conditions were transferred to downstream habitat, at least over the initial postproject period.

Ecology of Leuctra geniculata (Plecoptera: Leuctridae), an atlantomediterranean species on the north-eastern border of its area

The first records of Leuctra geniculata Stephens, 1836 in the north-eastern border of its area (the Czech Republic) are presented and an overview of references, synonyms and distribution of the species is given. The ecological preferences of the species, supported by chemical and hydromorphological parameters, are defined. Probable dissemination paths into the Czech Republic and the supposed life cycle of the species are discussed. Photographs of morphological characters, SEM photos of eggs, associated macroinvertebrate assemblages (EPT taxa) and maps of distribution are included.

A multimetric index based on benthic macroinvertebrates for evaluation of Atlantic Forest streams at Rio de Janeiro State, Brazil

This study describes the application of a protocol for biological assessment of water quality at first to third order streams at Serra dos Orgaos, an area covered by Atlantic Forest in Rio de Janeiro State, Brazil. Major impacts in the region are domestic effluents and deforestation. Our main objective is to establish biocriteria for the establishment of the Serra dos Orgaos Multimetric Index (SOMI) based on benthic macroinvertebrates. We used data from previous studies, sampled by experienced biologists, from 1999 through 2002. The benthic macroinvertebrate community was sampled in 12 reference sites and seven impaired sites in three river basins: Guapimirim, Macae and Grande, all from the same bioregion. From the 22 tested metrics, 6 were included in the SOMI (% Diptera, % Coleoptera, Family Taxa, EPT Taxa, BMWP-CETEC and % Shredders). Scores (5, 3 or 1) were developed for these metrics to allow for aggregation into the index. Seven intermediately impaired sites were used for evaluating the applicability of the multimetric index. We concluded that the SOMI is a robust easy-to-apply tool for biomonitoring programs in the Serra dos Orgaos region, south-east Brazil.

Hydromorphology – major results and conclusions from the STAR project

The major results and conclusions of the two papers in the hydromorphology section of the Hydrobiologia special issue on the EU STAR project are summarised. Several key findings have emerged from this research. Firstly, the hydromorphological characteristics of rivers between different geographical regions of Europe were found to vary considerably with rivers in each region possessing distinctive hydromorphological characteristics. Secondly, the hydromorphological attributes that most strongly influence two existing hydromorphological indices (the Habitat Quality Assessment and the Habitat Modification Score) were identified and attention was drawn to the accurate definition and recording of these attributes in field surveys and training courses. Thirdly, links between hydromorphological characteristics and macroinvertebrate quality indices were investigated. Two types of bank modification (resectioning and reinforcement) were significantly correlated with two biotic indices (EPT taxa and MTS), while channel modifications were negatively correlated with ASPT. While biotic indices were often strongly correlated with Habitat Quality Assessment they were less strongly related to Habitat Modification Score suggesting that physical habitat diversity may be more important in determining macroinvertebrate community structure than morphological alteration. The papers in this section provide important underpinning research for the implementation of the European Water Framework Directive. In both papers suggestions are made for further research on the hydromorphology of European rivers.

Preliminary testing of River Habitat Survey features for the aims of the WFD hydro-morphological assessment: an overview from the STAR Project

The UK River Habitat Survey (RHS) method for the assessment of hydro-morphological features was applied within the EU STAR project simultaneously with the collection of biological data. A subset of data from 79 sites affected by hydro-morphological alteration and belonging to 7 different stream types was analysed. The different features recorded within RHS were evaluated separately considering the characteristics associated with banks, channel and riparian zone. Different scores were assigned to selected features representing hydro-morphological alteration and naturalness of habitat. The ability of the different compartments to represent the quality gradient of sites was investigated. In addition, the link between macroinvertebrate community and hydro-morphological data was investigated, directly relating indices and metrics calculated from taxa list collected in a site to scores assigned to the RHS features. The sections highly affected by morphological alteration were channel geometry and bank profile. Metrics showing the best correlation with the features selected were EPT taxa, ASPT and ICMi (Inter-calibration Common Metric index). Among the indices studied, the HQA score (Habitat Quality Assessment) apparently played the most important role in structuring biological communities and the lentic-lotic character of rivers was also important.

Characterization of Benthic Communities and Physical Habitat in the Stanislaus, Tuolumne, and Merced Rivers, California

The primary goal of this study was to characterize physical habitat and benthic communities (macroinvertebrates) in the Stanislaus, Tuolumne and Merced Rivers in California's San Joaquin Valley in 2003. These rivers have been listed as impaired water bodies (303 (d) list) by the State of California due to the presence of organophosphate (OP) insecticides chlorpyrifos and diazinon, Group A pesticides (i.e., organochlorine pesticides), mercury, or unknown toxicity. Based on 10 instream and riparian physical habitat metrics, total physical habitat scores in the Stanislaus River ranged from 124 to 188 (maximum possible total score is 200). The highest total habitat score was reported at the upstream site. Tuolumne River physical habitat scores ranged from 86 to 167. Various Tuolumne River physical habitat metrics, including total habitat score, increased from downstream to upstream in this river. Merced River physical habitat scores ranged from 121 to 170 with a significant increase in various physical habitat metrics, including total habitat score, reported from downstream to upstream. Channel flow (an instream metric) and bank stability (a riparian metric) were the most important physical habitat metrics influencing the various benthic metrics for all three rivers. Abundance measures of benthic macroinvertebrates (5,100 to 5,400 individuals) were similar among the three rivers in the San Joaquin watershed. Benthic communities in all three rivers were generally dominated by: (1) Baetidae species (mayflies) which are a component of EPT taxa generally considered sensitive to environmental degradation; (2) Chironomidae (midges) which can be either tolerant or sensitive to environmental stressors depending on the species; (3) Ephemerellidae (mayflies) which are considered sensitive to pollution stress; and (4) Naididae (aquatic worms) which are generally considered tolerant to environmental stressors. The presence of 117 taxa in the Stanislaus River, 114 taxa in the Tuolumne River and 96 taxa in the Merced River implies that the benthic communities in these streams are fairly diverse but without a clear definition of benthic community expectations it is unknown if these water bodies are actually impaired.

Potential ecological effects of water extraction in small, unregulated streams

River regulation can have various effects on the natural flow regime, however the most obvious and perhaps pronounced hydrological effect is the reduction of total water discharge. Whilst there has been an increasing number of studies investigating the impacts of river regulation on lowland rivers, few studies have specifically investigated the effects of water extractions on small upland streams. In this study, we experimentally examined the effects of short-term, summer water extractions from small, unregulated streams. Five 30 m reaches were experimentally manipulated to divert a proportion of the total stream flow, and another five 30 m reaches were designated as controls, in the Yea River catchment, Victoria, Australia. The percentage of total discharge diverted from each experimental reach varied through time and between creeks (28–97%), with discharge always significantly reduced compared to control locations. All sites were monitored for available habitat, biofilm, water quality and macroinvertebrate diversity and density, fortnightly during February and March 2004. Despite the range of total stream volumes being extracted, the manipulation altered important ecological components of these unregulated creeks, including changes in physical habitat features (reduced stream wetted area and maximum stream depth) and reduced dissolved oxygen concentrations. Biofilm parameters showed a slight increase in diverted reaches, but were not statistically different from the controls. There was no statistical difference in total density of macroinvertebrates or EPT taxa; however, the density of Austrocercella mariannae (Notonemouridae) was significantly reduced in diverted reaches. Macroinvertebrate family level diversity, and the family diversity of grazers and shredders was reduced in diverted reaches. This study demonstrates that there are likely to be significant ecological impacts of extracting water in unregulated creeks. Whilst this study has demonstrated the need to consider environmental water requirements in unregulated streams, further studies are required to inform the debate about the volume, timing and predicted ecological response with improved environmental water. Copyright © 2006 John Wiley & Sons, Ltd.

Recovery of the macroinvertebrate community below a wastewater treatment plant input in a Mediterranean stream

We sampled chlorophyll a, benthic organic matter, and benthic macroinvertebrates in June 2001 in La Tordera stream (Catalonia, NE Spain), receiving a wastewater treatment plant (WWTP) input. Samples were collected in six equidistant transects in three reaches located upstream (UP), few m below (DW1), and 500 m below the WWTP input (DW2). Our first objective was to assess the effects of the point source on the structure and functional organization of the benthic macroinvertebrate community. Our second objective was to determine if the self-purifying capacity of the stream implied differences between the communities of the DW1 and the DW2 reaches. The WWTP input highly increased discharge, nutrient concentrations, and conductivity and decreased dissolved oxygen. At the DW1 and the DW2 reaches, taxa richness, EPT taxa (Ephemeroptera, Plecoptera, and Trichoptera), and Shannon diversity decreased and gatherer relative density increased relative to the UP reach. At the UP reach, CPOM and FPOM standing crops were similar, whereas at the DW1 and the DW2 reaches CPOM was two times higher than FPOM. Detailed analysis showed that major changes in the benthic community occurred abruptly between 80 and 90 m downstream of the point source (middle of the DW1 reach). At this location, chlorophyll a concentration, density of macroinvertebrates, taxa richness, and scraper relative density increased, whereas gatherer relative percentage decreased. The macroinvertebrate community at the DW2 reach was comparable to that at the second middle of the DW1 reach (DW1B). The macroinvertebrate community at the DW1B and the DW2 reaches were quite similar to that at the UP reach, indicating that the recovery capacity of the stream from nutrient enrichment was high.

Comparison of Benthic Macroinvertebrates Colonizing Sand, Wood, and Artificial Substrates in a Low-Gradient Stream

ABSTRACT We compared macroinvertebrate assemblages sampled from artificial and natural substrates within a small, sandy-bottomed coastal plain stream, Alabama, USA. Separate samples were collected from natural coarse woody debris (CWD) accumulations, benthic sand substrate, and Hester-Dendy multiplate samplers (HDs, 54-d incubations). Shannon's H′ was lowest and % dominant taxon was highest in sand samples. Proportion of the total assemblage as EPT taxa (Ephemeroptera, Plecoptera, and Trichcptera) was significantly higher on HDs than from sand, and proportion of the assemblage as Chironomidae was higher from sand than on CWD. Invertebrate biomass on HDs was almost two times higher than from sand, whereas biomass from sand was nearly an order of magnitude higher than biomass on CWD. TWINSPAN indicated CWD and HDs assemblages were distinctive from sand substrates, largely because of differential abundance of the midges Rheotanytarsus sp., Thienemanniella sp., Rheosmittia sp., and Polypedilum sp., the mayfly Stenonema smithae, and Cladocera. A subsequent splitting, based on relatively large abundance of Thienemanniella sp. and Oligochaeta in CWD, separated HDs and CWD assemblages. Our results suggest that HDs are not a quantitative mimic of either sand or CWD, leading us to conclude that the use of HDs is not a comprehensive substitute for sampling fauna established on natural sand or wood substrates in streams.

Spatio-temporal changes of benthic macroinvertebrates in a cold Arkansas tailwater

This paper investigates spatial, seasonal and long-term changes in benthic macroinvertebrates in riffles of a cold tailwater. Cold tailwaters initially disrupt previously existing macroinvertebrate assemblages, but little is known about the long-term biological effects of a stable cold thermal regime. Assemblages at an upstream and downstream site of the Little Red River, Arkansas were investigated almost 30 years apart (1971 and 1999). Based upon published literature demonstrating the stability of benthic assemblages within unaltered environments, we predicted that the assemblages would be similar for each variable investigated. The benthic macroinvertebrate assemblages can be characterized as low diversity, with a total of 17 taxa identified. Isopods and Diptera comprised ~80% of all individuals. Other than chironomids, insects and particularly EPT taxa were poorly represented. Recent macroinvertebrate densities were significantly greater compared to the historical study period for the downstream site. Assemblage comparisons revealed moderate differences between study periods. Macroinvertebrate density was significantly greater upstream than downstream in the 1971 study period, yet taxa richness was significantly greater downstream for both study periods. Faunal composition was significantly different for upstream and downstream sites. Seasonal differences in numerical standing crop were identified for the 1971 upstream and 1999 downstream data sets. Low to moderate levels of seasonal, spatial and historical variation among benthic macroinvertebrate assemblages were attributed to environmental (temperature and flow) stability. The lack of aquatic insects other than chironomids over a 30-year period is indicative of the extreme constraints placed upon insect development within this cold regulated river.

Effects of Lowhead Dams on the Ephemeropterans, Plecopterans, and Trichopterans Group in a North American River

ABSTRACT We assessed the effects of lowhead dams on the EPT group (ephemeropterans, plecopterans, and trichopterans) by sampling habitat and macroinvertebiates monthly from November 2000 to October 2001 at eight gravel bars centered around two lowhead dams on the Neosho River, Lyon County, Kansas. Sites included a reference and treatment site upstream and downstream from each dam. Percent EFT was greater at reference sites than upstream treatment sites, and was positively correlated with stream velocity and %gravel in the substrate, but negatively correlated with substrate compaction and %boulder in the substrate. These results are similar to those for large dams and suggest that differences in habitat around these lowhead dams are unfavorable for EPT taxa, a finding important to the conservation and restoration of biotic integrity in riverine ecosystems.

Comparison of macroinvertebrate assemblages of permanent and temporary streams in an Alpine flood plain, Switzerland

Temporary streams are a common but little studied feature of alpine flood plains. We examined macroinvertebrate assemblages of temporary and permanent alpine streams in the Swiss Alps over a seasonal cycle (spring through autumn). Temporary streams contained fewer taxa and lower zoobenthos abundances than permanent streams, although within stream type variability was high. Temporary streams that dried in early summer were dominated by Chironomidae and Oligochaeta, whereas those that dried later in summer were dominated only by Chironomidae. Permanent streams were dominated by Chironomidae and Turbellaria or Chironomidae and EPT taxa. No seasonal increase in taxon richness was evident in either stream type, but taxa were replaced by other taxa over time. Chironomid assemblages had higher richness in permanent streams, and Orthocladiinae were rare in temporary streams. The life cycle of the common simuliid Prosimulium latimucro was more synchronous, and its development faster, in temporary than permanent sites. High temperatures and low precipitation caused drought conditions in summer 2003. In one permanent stream, the assemblage was dominated by chironomids in 2002 (a normal weather year), while the turbellarian Crenobia alpina accounted for ∼ 50 % of the assemblage in 2003. Temporal changes in assemblage composition shifted 2-3 weeks earlier in 2003 compared to 2002. Development and growth of P. latimucro was faster in 2003 than in 2002. Although these temporary alpine streams displayed similar biotic characteristics to temporary streams in other biomes, they appear to be highly sensitive to inter-annual changes in climate.

English

Argus Energy (formerly Pen Coal Corporation) has been conducting spring and fall seasonal monitoring of water chemistry and benthic macroinvertebrates since 1995 on the Trough Fork watershed to determine the longterm downstream impacts of mining operations. Conductivity, TDS, and sulfates have remained relatively low at the upstream site since 1995 with the exception of October data since 2000. Although there was a noticeable increase in these parameters at the downstream site during active mining from October 1997, April levels have appeared to stabilize at levels about 3 times pre-mining levels. October levels have continued to Aspike@ since 2000 at both the upstream and downstream sites. Total individuals collected have been lower at the downstream site since October 2000, whereas prior to October 2000, total individuals had been higher at the downstream for 8 of the previous 10 sampling events. Although sporadic prior to October 1999, total taxa, EPT taxa, and percent mayflies has remained lower at the downstream site since April 2000. Pre-mining and early active mining upstream and downstream communities consisted of relatively equal proportions of sensitive, facultative, and tolerant individuals. Extremely large proportions of tolerant individuals were noted during the droughts of October 1998 and April 1999 at both sites. Since October 2002, the downstream site has become more facultative, and less sensitive. WV-SCI scores have ranged from pre-mining scores of 73 and 79, to lows of 47 and 41 during the drought years, to highs of 91 and 89 for the upstream and downstream sites, respectively. Usually, the downstream site has scored less than the upstream site in 10 out of 16 sampling seasons. Regression data does not show any trends correlating WV-SCI score to conductivity, TDS, sulfates, or aluminum at either the upstream or downstream sites utilizing data over 6 2 years. Some correlation between these parameters and mayfly abundance appear to exist. ______________________ 1 Paper was presented at the 2004 National Meeting of the American Society of Mining and Reclamation and The 25 th West Virginia Surface Mine Drainage Task Force, April 18-24, 2004. Published by ASMR, 3134 Montavista Rd., Lexington, KY 40502. 2 Ed J. Kirk, Director Biological Division, REI Consultants, Inc., Beaver WV 25813. Randall Maggard, Manager of Environmental Compliance, Argus Energy-WV, LLC., Dunlow WV 25511. Proceedings America Society of Mining and Reclamation, 2004 pp 1095-1127 DOI: 10.21000/JASMR04011095 Proceedings America Society of Mining and Reclamation, 2004

Development of standard protocols for macroinvertebrate assessment of soft‐bottomed streams in New Zealand

Macroinvertebrate communities in hard‐bottomed (HB) and soft‐bottomed (SB) streams were compared to address questions on sample substrata, sample area, and data interpretation. Communities at HB and SB reference sites (native bush catchments) were distinctly different. SB reference sites had 50% of the total taxa, 33% of the Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa, and significantly lower Macroinvertebrate Community Index (MCI) and Semi‐Quantitative MCI (SQMCI) scores than HB reference sites. Ten EPT genera were abundant (>20 individuals per sample) at HB reference sites compared with one EPT genus (Zephlebia) at SB reference sites. The densities of macroinvertebrates at SB reference sites were <10% of those at HB sites indicating the need to sample a larger area to obtain a representative sample. SB sites with severe urban and rural land use disturbance had significantly lower metric values than SB reference sites. The SQMCI was the only metric sensitive to moderate disturbance, and multivariate ordination further supported the value of relative abundance data in detecting moderate impairment in SB streams. Hand sampling of submerged wood added 16–40% more taxa in total, and 11–44% more EPT taxa to sweep‐net samples, indicating the importance of directly sampling wood in SB streams. The results supported separate collection methods and data interpretations for HB and SB streams proposed in recently published New Zealand protocols.

Instream community assessment of aquaculture effluents

The regionally concentrated commercial catfish industry has attracted attention to its possible contributions to basin contaminant loading. This study was included in a screening process to establish baseline bioassessment information for commercial aquaculture of the southeast United States. One valuable aspect of the typical drainage system in this industry's landscape is the assimilative capacity and transformation of contaminants associated with ditches. Two extensive commercial fish farm drainage systems in northeast Arkansas and affected receiving streams were examined for their response to potential nutrient related contamination. The research utilized modified Rapid Bioassessment Protocols (RBPs), as applied nationwide, in characterization and identification of potential water resource impairments. Additional biological impairment testing of related pond discharges and affected receiving streams was also conducted to further characterize potential effluent impacts. There was no observed significant toxicity ( P<0.05) in Pimephales promelas exposed for 48-h to pond discharges, while neonate production in Ceriodaphnia dubia was significantly reduced. Upstream samples yielded significant ( P<0.05) C. dubia toxicity and reproduction impairments, while downstream samples only yielded reproduction impairments. While physicochemical analyses indicated minor differences between fish pond effluents and receiving stream water, benthic community responses measured as taxa richness were not significantly different ( P=0.395) between receiving systems—upstream, facility effluent and downstream. Taxa richness of benthic macroinvertebrates was unaffected by pond discharge at all sites. Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies)—EPT taxa actually responded with increased abundance in receiving streams below the pond discharges. Taxa richness of fish was also unaffected in relation to upstream locations and downstream of the facility effluent release ( P=0.877) while fish abundance decreased. These findings suggest minimal detrimental instream effects result from the introduction of aquaculture effluents into receiving waters.

Life history and production of mayflies, stoneflies, and caddisflies (Ephemeroptera, Plecoptera, and Trichoptera) in a spring-fed stream in Prince Edward Island, Canada: evidence for population asynchrony in spring habitats?

We examined the life history and production of the Ephemeroptera, Plecoptera, and Trichoptera (EPT) community along a 500-m stretch of a hydrologically stable cold springbrook in Prince Edward Island during 1997 and 1998. Six mayfly species (Ephemeroptera), 6 stonefly species (Plecoptera), and 11 caddisfly species (Trichoptera) were collected from benthic and emergence samples from five sites in Balsam Hollow Brook. Eleven species were abundant enough for life-history and production analysis: Baetis tricaudatus, Cinygmula subaequalis, Epeorus (Iron) fragilis, and Epeorus (Iron) pleuralis (Ephemeroptera), Paracapnia angulata, Sweltsa naica, Leuctra ferruginea, Amphinemura nigritta, and Nemoura trispinosa (Plecoptera), and Parapsyche apicalis and Rhyacophila brunnea (Trichoptera). Life-cycle timing of EPT taxa in Balsam Hollow Brook was generally similar to other literature reports, but several species showed extended emergence periods when compared with other studies, suggesting a reduction in synchronization of life-cycle timing, possibly as a result of the thermal patterns in the stream. Total EPT secondary production (June 1997 to May 1998) was 2.74–2.80 g·m–2·year–1dry mass (size-frequency method). Mayflies were dominant, with a production rate of 2.2 g·m–2·year–1dry mass, followed by caddisflies at 0.41 g·m–2·year–1dry mass, and stoneflies at 0.19 g·m–2·year–1dry mass. More than half of the species found in the study stream represented new distribution records for Prince Edward Island.

The Influence of Adjacent Land Uses on Macroinvertebrate Communities of Prairie Streams in Missouri

ABSTRACT The impact of adjacent land uses on aquatic macroinvertebrate communities was assessed in three low gradient, prairie streams in Missouri, USA. Aquatic macroinvertebrates were collected from 17 sites during fall 1999, and spring and summer 2000; each site was bordered by a single land use practice. We found no significant differences in taxa diversity [richness, abundance, or Fisher's log-series a (FLSA)] or composition metrics (richness and abundance of EPT taxa, functional feeding groups or Chironomidae) attributable to adjacent land use during any season. However, FLSA was significantly affected by the distance of a site from the beginning of the perennial stream during the spring and summer. Little of the variation in taxa diversity was attributable to physicochemical factors. However, these factors were more important in explaining differences in diversity among sites during the drought (fall 1999) than in other seasons. Taxonomic composition of the macroinvertebrate community effectively discriminated among sites bordered by different land uses. Although compositional differences were season-specific, predators and chironomids were the most important groups accounting for signiticant differences among land use groups regardless of season. Moreover, compositional analysis, based on proportional abundances of taxa, revealed the importance of both stream identity and adjacent land use to community structure.