Behavioural and feeding responses of Echinogammarus meridionalis (Crustacea, Amphipoda) to acid mine drainage

As a result of mining activities the exposure of metal sulphides to oxidation takes place with consequent release of acid mine drainage (AMD). Biomonitoring instruments have been proven to have the best deterrent effect upon polluters. A new approach in online biomonitoring, with the Multispecies Freshwater Biomonitortrade mark (MFB), was developed combining behavioural and feeding responses of the Portuguese indigenous benthic shredder, Echinogammarus meridionalis (Pinkster, 1973) (Crustacea, Amphipoda). These endpoints, along with mortality, were measured and analyzed for a gradient of sublethal doses of AMD. Original river water was used as the control and three doses of treatments were attained by adding increasing volumes of AMD to the control. The increase in AMD concentration and concomitant decrease in pH and increase in the concentration of most metals was followed by an overall increase of the mortality, decrease of locomotion/feeding activity and inhibition of the feeding rate. Mortality was observed in the two highest concentrations of AMD. Significant decrease in average locomotion/feeding activity took place in the second treatment. Although an inhibition of feeding was observed along the gradient of AMD concentration only in the highest concentration the feeding rate was significantly reduced.     

Monitoring behavioural responses to metals in gammarus pulex (L.) (Crustacea) with impedance conversion

An impedance conversion technique was used to study the behaviour of Gammarus pulex (L.) exposed to acutely toxic concentrations of Pb (0.01, 0.05, 0.1 and 0.5 mg Pb 1^-1) and to field concentrations of Cu (≤ 0.05 mg Cu 1^-1). Initial stress responses were studied during short-term exposure (1 h), and sublethal toxic effects were monitored during 7 (Pb) and 35 days (Cu), respectively. Exposure to Pb caused 30 % mortality and resulted in a bioconcentration factor (BCF) of 2700 at 0.5 mg Pb l^-1 after 168 h. Exposure to Cu polluted stream water caused no mortality within 35 days, and uptake was low (BCF 5.8). Gammarus pulex reacted with initial stress responses to metal exposure within 30 min (Cu) or 1 h (Pb). The reactions consisted of increased ventilation and decreased locomotion. Sublethal concentrations of Pb and Cu caused toxic effects on the behaviour of G. pulex after several days of exposure, consisting of increased ventilation and decreased locomotion. Impedance conversion is an appropriate method for detecting stress responses to metals and can be used in “early warning” biomonitoring systems as well as for acute and chronic behavioural toxicity testing.     

Behavioural early warning responses to polluted water

Behavioural early warning responses to polluted surface water from an industrial effluent have been measured in two freshwater macroinvertebrate species using the four electrode impedance conversion technique. Specimens ofGammarus pulex (L.) andHydropsycho angustipennis (Curtis) were caught from reference streams and exposed to water from above and below the factory and to reference water for about 1 h with different kinds of behaviour being registered on-line every 10 min, such as time spent on locomotion, number of “high swimming peaks”, number of activity phases, cleaning, time spent on ventilation, ventilation frequency and netspinning. Additionally, G.pulex was exposedin situ above and 100 m, 500 m and 1000 m below the factory for 24 h. G.pulex reacted to water pollution within 1 h with less time spent on locomotion, fewer “high swimming peaks” and lower number of activity phases (p < 0.01). The same results were found after thein situ exposure (p < 0.05) and the pollution gradient mirrored survival and behavioural performance of the organisms. H. angustipennis reacted to water pollution within 1 h with decreased time spent on ventilation (p < 0.001), no change in locomotion and netspinning during daytime. During the night, exposure to water pollution resulted in increased locomotion (p < 0.0001). Simultaneous multispecies on-line biomonitoring of industrial effluents is recommended for reliable risk assessment.     

Rapid-behaviour responses as a reliable indicator of estrogenic chemical toxicity in zebrafish juveniles

Whereas biochemical and molecular parameters have been well recognised as important “signposts” of individual disturbance to endocrine disrupting chemical’s (EDCs) exposure, behavioural endpoints are yet greatly overlooked as a routine tool in environmental risk assessment of EDCs. However, life histories are intimately associated with numerous inter- and intra-specific interactions, which invariably depend on the performance of effective behaviours. Within fish species, one of the most important factors influencing energy turnover earlier in the development is locomotor activity. This essential trait reflects the organism’s ability to generate and coordinate the metabolic energy required for both reproductive and non-reproductive behaviours. Inappropriate movement responses due to toxic effects of contaminants may ultimately impact important ecological variables.Therefore, in the present study, the swimming bursts of zebrafish juveniles exposed for 40 d to the synthetic estrogen ethinylestradiol (EE₂), tested at environmentally relevant concentrations (nominal concentrations of 0.5, 1 and 2 ng L⁻¹), were investigated in order to address the potential of rapid-behaviour patterns as an effective response indicator of estrogenic endocrine disrupting chemical’s exposure. This synthetic estrogen was selected due to its high prevalence in aquatic ecosystems, ability to mimic natural estrogens and proven record of causing negative effects in fish reproduction. The behavioural responses were compared with established endpoints used in the screening of EE₂ effects at adulthood. Results indicate that zebrafish juveniles’ swimming activity was significantly decreased upon EE₂ exposure. Since reduced locomotion of zebrafish may impact foraging, predator avoidance, drift and transport, and even interfere with social and reproductive behaviours, a fitness decline of wild fish populations can ultimately be hypothesized. Furthermore, behavioural endpoints were found to display higher sensitivity to EE₂ than either vitellogenin gene induction or reproductive parameters determined at adulthood.Overall, the findings of this work not only demonstrate the power of high-throughput behavioural responses, able to act as sensitive early warning signals of EDC exposure, but also highlight the potential of behavioural endpoints in providing a more comprehensive and non-invasive measure of EDC’s exposure.     

Can behavioural responses of Lumbriculus variegatus (Oligochaeta) assess sediment toxicity? A case study with sediments exposed to acid mine drainage

The São Domingos mine (Portugal) is, potentially, a good site for ecotoxicological studies, due to a pH and metal gradient of acid mine drainage. In this study, the toxicity of several mine sediments was evaluated using the aquatic oligochaete Lumbriculus variegatus as a test organism. Our hypothesis was that exposure to contaminated sediments would cause behavioural early warning responses in L. variegatus. Five sites, with pH ranging from 2.5 to 6.5, and with associated metals, were investigated. The results showed poor sediment quality in most of the collected sediments and Fe, S and As were the dominant elements in the samples. High mortalities were observed, ranging from 32.6 to 100%, indicating severe contamination. The collected sediments did not support good L. variegatus growth and significantly changed its behaviour. Early warning responses consisted of decreased locomotion and decreased peristaltic movements. A behaviour inhibition will affect the ecosystem balance by limiting the organisms' ability to avoid capture, which leads to a higher risk of predation.     

Structural and functional responses of benthic invertebrates to imidacloprid in outdoor stream mesocosms

Structural and functional responses of a benthic macroinvertebrate assemblage to pulses of the insecticide imidacloprid were assessed in outdoor stream mesocosms. Imidacloprid pulses reduced invertebrate abundance and community diversity in imidacloprid-dosed streams compared to control streams. These results correlated well with effects of imidacloprid on leaf litter decomposition and feeding rates of Pteronarcys comstocki, a stonefly, in artificial streams. Reductions in oxygen consumption of stoneflies exposed to imidacloprid were also observed in laboratory experiments. Our findings suggest that leaf litter degradation and single species responses can be sensitive ecotoxicological endpoints that can be used as early warning indicators and biomonitoring tools for pesticide contamination. The data generated illustrates the value of mesocosm experiments in environmental assessment and how the consideration of functional and structural endpoints of natural communities together with in situ single species bioassays can improve the evaluation and prediction of pesticide effects on stream ecosystems.     

Sucralose - an ecotoxicological challenger?

The non-calorie sweetener sucralose - sucrose containing three chlorine atoms - is intensively sweet and has become a popular substitute for sugar. Its widespread use, exceptional stability in combination with high water solubility have thus resulted in contamination of recipient waters. Earlier studies on sucralose in aquatic organisms indicate low bioaccumulation potential and negligible acute/chronic toxicity, but the close structural resemblance with sucrose in combination with the importance of sugar in nature, warrant a more detailed ecotoxicological assessment. The aim of this investigation was therefore to study behavioural and physiological effects of sucralose in crustaceans. Our results show that both physiology and locomotion behaviour were affected by exposure to sucralose. In Daphnia magna, the behavioural response was manifested as altered swimming height and increased swimming speed, whereas in gammarids the time to reach food and shelter was prolonged. Regardless if these behavioural responses were initiated via traditional toxic mechanisms or stimulatory effects, they should be considered as a warning, since exposed organisms may diverge from normal behaviour, which ultimately can have ecological consequences.     

Effect of gender on physiological and behavioural responses of Gammarus roeseli (Crustacea Amphipoda) to salinity and temperature

The importance of potentially interacting factors in organisms responses to a stress are often ignored or underestimated in ecotoxicology. In laboratory experiments we investigated how gender, temperature and age influence the behaviour and the physiology of the freshwater amphipod Gammarus roeseli under salinity stress. Our results revealed a significant higher sensitivity of females in survival, ventilation and ionoregulation whereas no inter-age differences were reported. Water temperature also exerted a significant effect in survival and ventilation of G. roeseli. Some of those factors appeared to interact significantly. This study provides evidence that gender can affect organisms responses to a stressor and consequently has to be considered while assessing a stress impact. We discussed the potential relationships between biological and behavioural responses.     

The freshwater planarian Polycelis felina as a sensitive species to assess the long-term toxicity of ammonia

Behavioural endpoints are a good link between physiological and ecological effects. However long-term behavioural endpoints are not uniformly studied over all different organism groups. For example behaviour has been scarcely studied in planarians. Unionized ammonia (NH₃) is one of the most widespread pollutants in developed countries, and is known to alter animal behaviour. In this study a long-term (30 d) bioassay was conducted to assess the effect of this pollutant on survival and behavioural activity (e.g. locomotion activity) of the freshwater planarian Polycelis felina. One control and three environmentally-realistic concentrations of unionized ammonia (treatments of 0.02, 0.05, and 0.09 mg N-NH₃ L⁻¹) were used in quintuplicate. The behaviour of planarians was measured after 0, 10, 20 and 30 d of ammonia exposure. Mortality was recorded every 2 d. Unionized ammonia increased mortality in the two highest NH₃ concentrations and the locomotory activity was depressed in all treatments after 20 d of exposure. Behavioural effect was observed at concentrations 20 times lower than the short-term LC50 for this species. Previous studies proposed safe concentrations of unionized ammonia of 0.01-0.10 mg N-NH₃ L⁻¹ to aquatic ecosystems, but our study has shown that these concentrations will affect planarians. Because planarians play a key role in streams (as predator/scavenger), safe concentrations should be below 0.02 mg N-NH₃ L⁻¹ to protect this species in the freshwater community. Our results can contribute to improve the knowledge about ammonia toxicity to freshwater ecosystems, we recommend that safe concentrations of unionized ammonia should be based on very sensitive species.     

Biological effects of palytoxin-like compounds from Ostreopsis cf. ovata: A multibiomarkers approach with mussels Mytilus galloprovincialis

Massive blooms of the harmful benthic dinoflagellate Ostreopsis cf. ovata are of growing environmental concern in the Mediterranean, having recently caused adverse effects on benthic invertebrates and also some intoxication episodes to humans.The toxicological potential of produced palytoxin-like compounds was investigated in the present study on a typical marine sentinel species, the mussel Mytilus galloprovincialis. Organisms were sampled during various phases of a O. cf. ovata bloom, in two differently impacted sites. The presence of the algal toxins was indirectly assessed in mussels tissues (mouse test and hemolysis neutralization assay), while biological and toxicological effects were evaluated through the measurement of osmoregulatory and neurotoxic alterations (Na⁺/K⁺-ATPase and acetylcholinesterase activities), oxidative stress responses (antioxidant defences and total oxyradical scavenging capacity), lipid peroxidation processes (level of malondialdehyde), peroxisomal proliferation, organelle dysfunctions (lysosomal membrane stability, accumulation of lipofuscin and neutral lipids), immunological impairment (granulocytes percentage).Obtained results demonstrated a significant accumulation of algal toxins in mussels exposed to O. cf. ovata. These organisms exhibited a marked inhibition of the Na⁺/K⁺-ATPase activity and alterations of immunological, lysosomal and neurotoxic responses. Markers of oxidative stress showed more limited variations suggesting that toxicity of the O. cf. ovata toxins is not primarily mediated by an over production of reactive oxygen species. This study provided preliminary results on the usefulness of a multi-biomarker approach to assess biological alterations and toxicological events associated to blooms of O. cf. ovata in marine organisms.     

Feeding preferences of two detritivores related to size and metal content of leaves: the crustaceans Atyaephyra desmarestii (Millet) and Echinogammarus meridionalis (Pinkster)

The equilibrium of the structure and functioning of freshwater ecosystems is dependent of detritivores that link all the other functional groups. The preference for feeding leaves with different diameters (particle size) and leaves with metal contamination (several concentrations of the essential metals copper and zinc) were determined for two detritivores, the decapod Atyaephyra desmarestii and the amphipod Echinogammarus meridionalis. Several no-choice and multi-choice assays were done to determinate which leaf diameter the amphipod and the decapod species would eat when they had or not had alternatives available and include a set of dual-choice assays with contaminated and uncontaminated foods. No significant preference was shown by either species relative to the diameter of leaves, either on no-choice or multi-choice assays. The presence of essential metals on food did not had any influence on the feeding choice of these organisms over the concentration range studied. Both showed no preference on ingesting food spiked with these essential metals, except E. meridionalis which preferred ingesting leaves with 2.19 μg.l^?1 of copper instead of uncontaminated leaves. For further works, despite no preference for leaves with a certain diameter, the leaves with 0.70 cm (0.385 cm²of area) and with 0.50 cm (1.767 cm² of area) should be used for A. desmarestii and E. meridionalis, respectively. Furthermore, to maintain E. meridionalis, the diet should include some percentage of copper in order to accomplish metabolic needs.     

Histopathological and biochemical alterations of the earthworm (Lumbricus Terrestris) as biomarker of soil pollution along Porsuk River Basin (Turkey)

This study investigated biomarker responses of the earthworm Lumbricus terrestris in order to evaluate the soil pollution along Porsuk River Basin. Samples consisted of animals from six sites that are agricultural regions and a forested control. Histopathological and biochemical alterations were examined. Significant histopathological alterations were observed in animals from three of the sampling sites. There was an enlargement of epithelial cell lining, mucus cell hyperplasia and increase in mucus secretion. Circular and longitudinal muscles lost their structural integrity. Chloragogenous tissue was dilated and vocuolized. Necrosis was observed in the cells and tissues of some affected worms. A load of heavy metals in tissues of animals was determined. Heavy metals were found to be accumulated particularly in longitudinal muscles of animals. CAT activity was found to be increased in animals from three of the experimental sites. GST activity was also increased in five sites while it was stable in one site. The results have shown that animals from locations particularly that are close to urbanized and industrialized regions were seriously affected from the soil pollution around the basin. These results are reflecting the biological effects of soil pollution around Porsuk River Basin on the indicator organism L. terrestris and constitute an early warning of ecological change in relation to human health.     

Trophic transfer and accumulation of mercury in ray species in coastal waters affected by historic mercury mining (Gulf of Trieste,northern Adriatic Sea)

Total mercury (Hg) and monomethylmercury (MMHg) were analysed in the gills, liver and muscle of four cartilaginous fish species (top predators), namely, the eagle ray (Myliobatis aquila), the bull ray (Pteromylaeus bovinus), the pelagic stingray (Dasyatis violacea) and the common stingray (Dasyatis pastinaca), collected in the Gulf of Trieste, one of the most Hg-polluted areas in the Mediterranean and worldwide due to past mining activity in Idrija (West Slovenia). The highest Hg and MMHg concentrations expressed on a dry weight (d.w.) basis were found in the muscle of the pelagic stingray (mean, 2.529 mg/kg; range, 1.179–4.398 mg/kg, d.w.), followed by the bull ray (mean, 1.582 mg/kg; range, 0.129–3.050 mg/kg d.w.) and the eagle ray (mean, 0.222 mg/kg; range, 0.070–0.467 mg/kg, d.w.). Only one specimen of the common stingray was analysed, with a mean value in the muscle of 1.596 mg/kg, d.w. Hg and MMHg contents in the bull ray were found to be positively correlated with species length and weight. The highest MMHg accumulation was found in muscle tissue. Hg and MMHg were also found in two embryos of a bull ray, indicating Hg transfer from the mother during pregnancy. The number of specimens and the size coverage of the bull rays allowed an assessment of Hg accumulation with age. It was shown that in bigger bull ray specimens, the high uptake of inorganic Hg in the liver and the slower MMHg increase in the muscle were most probably due to the demethylation of MMHg in the liver. The highest Hg and MMHg contents in all organs were found in the pelagic stingray, which first appeared in the northern Adriatic in 1999. High Hg and MMHg concentrations were also found in prey species such as the banded murex (Hexaplex trunculus), the principal prey of the eagle rays and bull rays, the anchovy (Engraulis encrasicholus) and the red bandfish (Cepola rubescens), which are preyed upon by the pelagic stingray, as well as in zooplankton and seawater. Based on previously published data, a tentative estimation of MMHg bioamagnification was established. The average increase in MMHg between seawater, including phytoplankton, and zooplankton in the Gulf was about 10⁴, and MMHg in anchovy was about 50-fold higher than in zooplankton. The bioaccumulation of MMHg between seawater and small pelagic fish (anchovy) amounted to 10⁶ and between water and the muscle of larger pelagic fish (pelagic stingray) to 10⁷. The MMHg increase between surface sediment and benthic invertebrates (murex) and between benthic invertebrates and small benthic fish was 10². Ultimately, the trophic transfer resulted in a 10³ accumulation of MMHg between water and muscle of larger benthic fish (bull ray, eagle ray, common stingray), suggesting lower bioaccumulation by benthic feeding species.     

A microcosm system to evaluate the toxicity of the triazine herbicide simazine on aquatic macrophytes

This study evaluates the effects of the triazine herbicide simazine in an outdoor pond microcosm test system that contained two submerged rooted species (Myriophyllum spicatum and Elodea canadensis) and two emergent rooted species (Persicaria amphibia and Glyceria maxima) over a period of 84 days. Simazine was applied to the microcosms at nominal concentrations of 0.05, 0.5 and 5 mg/L. General biological endpoints and physiological endpoints were used to evaluate herbicide toxicity on macrophytes and the algae developing naturally in the system.Concentration-related responses of macrophytes and algae were obtained for the endpoints selected, resulting in a no observed ecologically adverse effect concentration (NOEAEC) at simazine concentrations of 0.05 mg active ingredient/L after 84 days. E. canadensis was the most negatively affected species based on length increase, which was consistently a very sensitive parameter for all macrophytes. The experimental design presented might constitute a suitable alternative to conventional laboratory single-species testing.     

Continuous automated imaging-in-flow cytometry for detection and early warning of Karenia brevis blooms in the Gulf of Mexico

Monitoring programs for harmful algal blooms (HABs) typically rely on time-consuming manual methods for identification and enumeration of phytoplankton, which make it difficult to obtain results with sufficient temporal resolution for early warning. Continuous automated imaging-in-flow by the Imaging FlowCytobot (IFCB) deployed at Port Aransas, TX has provided early warnings of six HAB events. Here we describe the progress in automating this early warning system for blooms of Karenia brevis. In 2009, manual inspection of IFCB images in mid-August 2009 provided early warning for a Karenia bloom that developed in mid-September. Images from 2009 were used to develop an automated classifier that was employed in 2011. Successful implementation of automated file downloading, processing and image classification allowed results to be available within 4 h after collection and to be sent to state agency representatives by email for early warning of HABs. No human illness (neurotoxic shellfish poisoning) has resulted from these events. In contrast to the common assumption that Karenia blooms are near monospecific, post-bloom analysis of the time series revealed that Karenia cells comprised at most 60–75 % of the total microplankton.     

Behaviour of pharmaceuticals in spiked lake sediments - effects and interactions with benthic invertebrates

The behaviour and effects of atorvastatin (ATO), carbamazepine (CBZ), and 17α-ethinylestradiol (EE2) were investigated in spiked lake sediments, at concentrations up to 56.5 mg kg⁻¹ dry weight (dw), with the benthic invertebrates Chironomus dilutus and Hyalella azteca. Desorption constants were calculated in the presence and absence of animals, using linear isotherms, yielding K_d values of 28.2, 189.0 and 125.1 L kg⁻¹ (ATO), 73.7, 201.7 and 263.2 L kg⁻¹ (CBZ), and 114.9, 114.2 and 519.2 L kg⁻¹ (EE2) for C. dilutus, H. azteca, and without animals, respectively. For ATO and CBZ, K_d values were smaller in the presence of C. dilutus, indicating greater desorption to the overlying water from bioturbation, which is consistent with the predominantly benthic occurrence of C. dilutus compared to H. azteca. In contrast, due to its greater hydrophobicity, bioturbation did not significantly affect desorption of EE2. No significant toxicity was observed, indicating decreased bioavailability of the chemicals sorbed to sediments compared with water-only toxicity assays.     

Comparison of solid-phase bioassays and ecoscores to evaluate the toxicity of contaminated soils

Five bioassays (inhibition of lettuce germination and growth, earthworm mortality, inhibition of springtail population growth, avoidance by springtails) were compared, using four coke factory soils contaminated by PAHs and trace elements, before and after biotreatment. For each bioassay, several endpoints were combined in an ‘ecoscore’, a measure of test sensitivity. Ecoscores pooled over all tested bioassays revealed that most organisms were highly sensitive to the concentration of 3-ring PAHs. When four soils were combined, behavioural tests using the springtail Folsomia candida showed higher ecoscores, i.e. they were most sensitive to soil contamination. However, despite overall higher sensitivity of behavioural tests, which could be used for cheap and rapid assessment of soil toxicity, especially at low levels of contamination, some test endpoints were more sensitive than others, and this may differ from a soil to another, pointing to the need for a battery of bioassays when more itemized results are expected.     

Haneş and Valea Vinului (Romania) closed mines Acid Mine Drainages (AMDs) – Actual condition and passive treatment remediation proposal

Acid Mine Drainages (AMDs) from Hane? and Valea Vinului (Romania) closed mines were considered for characterization and treatment using a local zeolitic volcanic tuff, ZVT, (M?cica?, Cluj County, Romania). Water samples were collected from two locations, before and after discharging point in case of Hane? mine, and on three horizons in case of Valea Vinului mine. Physico-chemical (pH, total solid, heavy metal ions concentration) analyses showed that the environment is strongly affected by these AMD discharges even if the mines were closed years ago. Iron, manganese and zinc were the main pollutants identified in Hane? mine AMD, while zinc is the one mainly present in case of Valea Vinului AMD. A batch technique (no stirring) in which the ZVT was put in contact with the AMD sample was proposed as a passive remediation technique. ZVT successfully remove heavy metal ion from AMD. According to heavy metal ion concentrations, removal efficiencies are reaching 100%, varying as follows, Fe²⁺ > Zn²⁺ > Mn²⁺. When the ZVT was compared with two cationic resins (strong, SAR and weak acid, WAR) the following series was depicted, SAR > ZVT > WAR.     

Effect of water current on the distribution of polycyclic aromatic hydrocarbons,heavy metals and benthic diatom community in sediments of Haihe estuary,China

The pollution loads continuously increased in Haihe estuary, of Tianjin, China, due to intensive human activities, especially the construction of the Haihe Gate and Lingang Industrial Area. In 2011, hydrological variability in Haihe estuary was investigated and sediments were collected. Total organic carbon (TOC), particle size, total polycyclic aromatic hydrocarbons (ΣPAHs), heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn), and benthic diatom community were analyzed. The highest concentrations of ΣPAHs and heavy metals were found near the Haihe Gate. The Shannon diversity index and the relative abundance of Coscinodiscus perforatus (RC) indicated a decreasing trend seaward. Results of Pearson correlation analysis illustrated significant relations between water current velocity and ΣPAHs (p?p?p?相似文献   

The effects of road and bridge construction on the bank-root macrobenthic invertebrates of a Southern Nigerian stream

A comparative study was conducted at three stations on a fourth order Nigerian stream to evaluate the effects of a road and bridge construction on the macrobenthic invertebrates of the bank-root biotope. Siltation and sedimentation appear to be the important factors affecting macroinvertebrates. At station 2, the construction site, there was a considerable reduction in the occurrence and abundance of invertebrate taxa; different groups of invertebrates showed varying responses to perturbational stress; the taxa richness, general diversity and evenness were also low. Irregular fluctuations in diversity and evenness suggested that the benthic community of station 2 was less stable than those of upstream and downstream stations. The concentrated dominance of Ephemeroptera and Coleoptera at station 2, despite low diversity, reflected the ability of a few tolerant taxa to occur there in high abundance. Faunal comparisons of the three stations confirmed the perturbational stress caused by construction activities.