Kick Sampling Research Articles

Effect of Wastewater Discharge From Coffee Processing Plant on River Water Quality, Sidama Region, South Ethiopia.

In Ethiopia, most of the coffee processing plants are generating large amounts of wastewater with high pollutant concentrations and discharge directly into the water bodies untreated or partially treated. The main objective of this study was to assess the effects of coffee wastewater discharged to river water quality using physicochemical parameters and macro-invertebrate indices. This study was conducted from November to the end of December 2019. Ten wastewater and river water samples were taken from coffee the processing plant and river. The macro-invertebrate samples were collected by kick sampling technique using a standard hand net. Shannon and Simpson diversity indices were examined at 3 sampling stations. The Pielou evenness index was also determined. It was found that except for TDS all the parameters of the raw wastewater and river water did not comply with the international discharge limit. The mean concentration of Faro coffee processing plant wastewater were BOD5 (2409.6 ± 173.1 mg/L), COD (4302 ± 437 mg/L), TSS (2824.6 ± 428.4 mg/L), TDS (3226 ± 623.6 mg/L), and TS (4183.3 ± 432.9 mg/L). Whereas from Bokaso coffee processing plant were BOD5 (3770 ± 604.4 mg/L), COD (4082.6 ± 921.9 mg/L), TSS (2766 ± 501.7 mg/L), TDS (3017 ± 747.6 mg/L), and TS (3874 ± 471.1 mg/L). A total of 392 macroinvertebrates belonging to 24 families and 7 orders were collected. The benthos assemblage communities in this river were 40, 56, and 296 at downstream 1, downstream 2, and upstream respectively. The value of the Simpson diversity index varies from 0.4 to 0.75. In the same manner, the value of the Shannon diversity index also varied from 0.5 to 1.36. Most of the physicochemical parameters of the raw wastewater were beyond the national and international discharge limits. The quality of Orsha river water downstream was more adversely affected compared to upstream.

Seasonal changes in the abundance of benthic macroinvertebrates & physico-chemical condition of Moussa Stream Bida, Nigeria

Seasonal changes in the abundance of benthic macroinvertebrates and physico-chemical condition of Moussa Stream, Bida Nigeria, were studied monthly from January to August 2017. Macroinvertebrates were sampled using modified kick sampling techniques. Three different sampling stations were selected along the course of the Stream. The results from the stream showed that water temperature (24.9-27.50C), Depth (14.7-45.8cm), Flow velocity (0.14-0.23m/s), Biochemical oxygen demand (2.0-7.0mg/L), pH (6.33-8.6), Conductivity (20-63μ/cm), Alkalinity (8-30mg/L), Turbidity (61-285NTU), Nitrate (0.87-3.85mg/L) and Phosphate (0.31-1.01mg/L) were within the maximum permissible limit (WHO, SON) except Dissolved oxygen (3.1-10mg/L). Most of the parameters investigated with the exception of depth and flow velocity showed no significant difference (p>0.05) among all the sampling stations. Temperature, depth and flow velocity showed no significant differences with season. pH, DO, BOD5, Turbidity, Conductivity, Alkalinity, Nitrate, and Phosphate were significantly higher during wet season. A total of 471 individuals from 30 species and 20 families of invertebrates were recorded. The overall macroinvertebrates recorded from station 1, 2 and 3 were 166(35.24%), 149(31.63%) and 156(33.12%). Overall, there was significant difference (P<0.05) in number of individuals among the sampling stations. The abundance according to the Orders revealed that Coleopterans, Odonata and Hemipterans were the most common groups encountered. Ephemeroptera Diptera, Mollusca and Oligochaeta were sparingly found in all stations. The percentage and total number of individuals of macroinvertebrates recorded during the study period shows 67.09% (316 individuals) in dry season and the remaining 32.90% (155 individuals) were recorded in rainy season. CCA result correlated positively between species abundances and measured environmental variables. Low density of pollution sensitive macro invertebrates groups and the deteriorating water quality were implications of pollution stress caused by anthropogenic activities.
 Key words: seasonal changes, macroinvertebrates, stream, Bida.

Assessment of water quality using biological monitoring working party (BMWP) and average score per taxon (ASPT) score at Kanye and Magaga dams, Kano

Macro invertebrate biotic indices have been widely used to assess quality of water bodies in the world. The Biological Monitoring Working Party (BMWP) and its Average Score Per Taxon (ASPT) score system is one of the most common biotic indices in use and has been applied to various streams and rivers throughout Europe and world. This study examines the water quality at Kanye and Magaga Dams using the BMWP/ASPT score index for the first time. Macro invertebrates were sampled from the upper and lower parts of the Dam using standard kick sampling techniques and identified to family level. The computed BMWP/ASPT score revealed higher value at the upper parts than the lower parts of the Dams. Kanye Dam showed a cumulative BMWP/ASPT scores of 50 and 3.85 while at Madaga Dam the cumulative BMWP/ASPT scores were 61 and 2.66 respectively, which are within class III category of moderately polluted water body. One way analysis of variance result revealed a significant difference (p<0.05) in BMWP/ASPT score value between the lower and upper part of both Dams. The result showed macro invertebrates were more diverse at the upper part than the lower part of the Dams. This study has further strengthened the use of BMWP/ASPT score index as an index of organic pollution in Nigerian water bodies. However additional application and validation is required to develop an adopted version BMWP/ASPT score index based on the sensitivity of our local taxa. Key words: Biotic index, Macro invertebrates, Pollution,

Qualitative habitat evaluation index and some selected macroinvertebrate taxa metrics as a diagnostic tool for assessing pollution loads in a municipal river in north central Nigeria

Pollution load in a municipal river in north central Nigeria was assessed using qualitative habitat evaluation index and some selected macroinvertebrate taxa metrics. The study was conducted for a period of twelve (12) months, spanning from March, 2017 to February, 2018, in four sampling stations. Station 1 was the reference site located in a relatively unperturbed area close to the river source. Macroinvertebrates were sampled using the kick sampling method of a D-frame net. Percentages of Ephemeroptera, Plecoptera and Trichoptera (EPT) and Chironomidae+Oligochaeta were calculated to ascertain the ecological state of the river. The Qualitative Habitat Evaluation Index (QHEI) values portray a moderately impaired site. Station 1 QHEI was 76.15% which was the highest value recorded while station 4 was the worst hit among the sampled stations with 42.69%. Percentage EPT calculated showed that station 1 had the highest composition of the group with 13.12% while station 4 % EPT was 0.147. Further lending credence to the heavily perturbed state of station 4 is the percentage Chironomidae + Oligochaeta with 7.34% composition, which is much lower than that of station 1 the relatively unperturbed station. The study was able to elucidate the level of pollution loads in each of the stations sampled and it was noticed that pollution load was increased downstream from station 1 to station 4. A more detailed study on the use of biotic indices to assess the ecological status of rivers in the North central region of Nigeria were the River Chanchaga is located is recommended to further ascertain the level of disturbance the rivers are undergoing. This can be best done using macroinvertebrates predictive protocols and traits based monitoring approach.Keywords: Ecological Integrity, Pollution loads, QHEI, EPT, River Chanchaga, Nigeria

Do carabids (Coleoptera: Carabidae) and chironomids (Diptera: Chironomidae) exhibit similar diversity and distributional patterns along a spatio-temporal gradient on a glacier foreland?

Carabid beetles and chironomid midges are two dominant cold-adapted taxa, respectively on glacier forefiel terrains and in glacial-stream rivers. Although their sensitivity to high altitude climate warming is well known, no studies compare the species assemblages exhibited in glacial systems. Our study compares diversity and distributional patterns of carabids and chironomids in the foreland of the receding Amola glacier in central-eastern Italian Alps. Carabids were sampled by pitfall traps; chironomids by kick sampling in sites located at the same distance from the glacier as the terrestrial ones. The distance from the glacier front was considered as a proxy for time since deglaciation since these variables are positively correlated. We tested if the distance from the glacier front affects: i) the species richness; ii) taxonomic diversity; and iii) species turnover. Carabid species richness and taxonomic diversity increased positively from recently deglaciated sites (those c. 160 m from the glacier front) to sites deglaciated more than 160yrs ago (those located &gt;1300 m from glacier front). Species distributions along the glacier foreland were characterized by mutually exclusive species. Conversely, no pattern in chironomid species richness and turnover was observed. Interestingly, taxonomic diversity increased significantly: closely related species were found near the glacier front, while the most taxonomically diverse species assemblages were found distant from the glacier front. Increasing glacial retreat differently affect epigeic and aquatic insect taxa: carabids respond faster to glacier retreat than do chironomids, at least in species richness and species turnover patterns.

A survey of macroinvertebrate assemblage of Ikwu River, Umuahia, southeast Nigeria

Macroinvertebrate fauna of Ikwu River, Umuahia, Nigeria was studied in the 3 stations to evaluate the composition, abundance and distribution vis-a-vis environmental conditions and anthropogenic impacts. Macroinvertebrate fauna was sampled between January and June 2016 using the modified kick sampling technique as well as sweeping of aquatic macrophytes with hand net. A total of 168 macroinvertebrate individuals comprising of four benthic fauna group and seven (7) taxa was recorded. Percentage composition of the taxa showed that aquatic snail (Bulinus globosus) was the highest (55.36%) while water spider (Argyroneta aquatica) was the least (0.60%). Spatially, Station 3 recorded the highest number of individuals (116), followed by Station 1 (28 individuals) and Station 2 (24 individuals). Diversity assessment recorded higher Shannon-Weiner diversity index (H) in Station 1(0.8058) than in Stations 2 (0.4563) and 3 (0.6978). Magalef Species Richness was highest in Station 3 (0.8415), followed by Station 2 (0.6293) and Station 1 (0.6002). Evenness Index was highest in Station 1 (0.7462) and least in Station 3 (0.4019). The diversity indices, which were a reflection of the species composition, abundance and distribution, were equally poor.Keywords: Macroinvertebrates, environmental conditions, anthropogenic activities, water quality

Effects of hydropeaking on benthic invertebrate community composition in two central Norwegian rivers

AbstractHydropower regulations can have dramatic impacts on river ecological communities. The operation of hydropower stations is related to power demands, but their releases in the receiving water body causes sudden changes in flow, which in turn affect the biota. The effects of such flow variations on benthic invertebrates is not fully understood. Here, we studied the effects of duration and intensity of hydropeaking on benthic invertebrates in two rivers over a 3.5‐year period. We used both quantitative (Surber) and semiquantitative (kick samples) sampling methods to compare the ramping zone with the permanently water covered zone downstream of the hydropower plant, and with corresponding unaffected upstream areas. The ramping zone had a different invertebrate community composition and lower benthic density than other areas, especially after hydropeaking. Mayflies and chironomids were most negatively affected by hydropeaking and oligochaetes largely unaffected. Chironomids and the mayfly Baetis rhodani were able to recolonize the ramping zone and almost reach densities similar to deeper areas within 48 days following hydropeaking. The relative abundance of filter feeders tended to increase and gatherers/collectors tended to decrease from the ramping zone towards the deep, permanently water covered areas. In corresponding areas upstream of the power plant, the relative abundance of different functional feeding groups was the same in the mid‐channel and shore sites. Our study shows that hydropeaking has clear impacts on the functional structure of benthic invertebrates below the power plants. The ecological impact of hydropeaking on invertebrate communities should thus be taken into account, for example, by reducing the amplitude and duration of flow fluctuations.

Biodiversity and Seasonal Variation of Macro Invertebrates in Four Water Bodies in Odogbolu Local Government Area of Ogun State

The biodiversity and seasonal variation of aquatic macroinvertebrates in four different water bodies in Ijagun, Ijele, Odepo and Imaweje in Odogbolu Local Government Area of Ogun State were investigated using modified kick sampling technique between July and December 2014. The aquatic macroinvertebrates were sampled twice in a month using a scoop net (0.5mm mesh size with 0.4m diameter). The collected samples were preserved separately in 10% formalin and later identified. The physical properties (air and water temperature ( o C), water current and water depth) of the water bodies were measured. Analysis of variance and spear man analytical tools were used to analyze the collected data. The different aquatic macro-invertebrates encountered belong to the super phylum Arthropoda, and three phylaviz: Mollusca, Annelida and Nematoda. The most abundant macro-invertebrate group was insects belonging to the orders Diptera (Simuliumyahense, Chironomussp., Anophelissp., and Cricotopus sp. ), Odonata (Agrocnemisfemina, Abiaserica, Macromiasp and Calopteryx sp. ), Coleoptera (Dysticusmarginalis and Hydrophylis sp. ), and Heteroptera (Gerrislacustris). The correlation coefficients (rho) of water depth, water current, water and air temperature in relation to frequency of occurrence of macro invertebrates were found to be -6.2, -4.2, -4.6 and -2.6 respectively. Water depth was the strongest factor that could determine the abundance of organisms. All physical properties showed inverse relationship with variation of aquatic macro invertebrates in the water bodies.

A comparison of upland stream invertebrates in moorland and coniferous woodland in North York Moors National Park, UK

Conversion of moorland to coniferous woodland is a common land use change in the high latitude uplands. Conifer woodlands are known to increase detrimental acidification in upland streams but can benefit some invertebrates by increasing allochthonous inputs. We aimed to identify the effects of conifer woodlands on benthic stream macroinvertebrate communities in North York Moors National Park, which has some of the most acidified streams in the United Kingdom. Benthic invertebrates from 8 moorland and 8 conifer woodland catchments were gathered using kick sampling in 2014. Taxonomic composition and diversity differed significantly in woodlands and moorlands, with woodland communities showing higher diversity and species characteristic of lower levels of stressors. Moorland and woodland communities did not differ in average acid sensitivity, and taxa were typical of close-to-neutral pH, matching spot pH measurements taken during sampling that were 2–3 pH units higher than in 2005. We conclude that conversion of moorland to coniferous woodland does not necessarily detrimentally affect upland stream invertebrate communities, and that those on the North York Moors are not always highly acid-tolerant, perhaps indicating biotic recovery from previous acidification.

Comparability of macroinvertebrate biomonitoring indices of river health derived from semi-quantitative and quantitative methodologies

Aquatic macroinvertebrates have been the basis for one of the primary indicators and a cornerstone of lotic biomonitoring for over 40 years. Despite the widespread use of lotic invertebrates in statutory biomonitoring networks, scientific research and citizen science projects, the sampling methodologies employed frequently vary between studies. Routine statutory biomonitoring has historically relied on semi-quantitative sampling methods (timed kick sampling), while much academic research has favoured fully quantitative methods (e.g. Surber sampling). There is an untested assumption that data derived using quantitative and semi-quantitative samples are not comparable for biomonitoring purposes. As a result, data derived from the same site, but using different sampling techniques, have typically not been analysed together or directly compared. Here, we test this assumption by comparing a range of biomonitoring metrics derived from data collected using timed semi-quantitative kick samples and quantitative Surber samples from the same sites simultaneously. In total, 39 pairs of samples from 7 rivers in the UK were compared for two seasons (spring and autumn). We found a strong positive correlation (rs=+0.84) between estimates of taxa richness based on ten Surber sub-samples and a single kick sample. The majority of biomonitoring metrics were comparable between techniques, although only fully quantitative sampling allows the density of the community (individual m−2) to be determined. However, this advantage needs to be balanced alongside the greater total sampling time and effort associated with the fully quantitative methodology used here. Kick samples did not provide a good estimate of relative abundance of a number of species/taxa and, therefore, the quantitative method has the potential to provide important additional information which may support the interpretation of the biological metrics.

Assessing candidate metrics for the ecological quality of TFTW (tidal freshwaters in transitional waters) in Ireland using benthic invertebrates

There is an obligation under the Water Framework Directive (WFD, 2000/60/EC) not just to establish the ecological status of water bodies, but to ensure that they achieve ‘good’ quality. However, in some cases, the criteria have been difficult to establish, and one such case is that for Tidal Freshwaters in Transitional Waters (TFTW).In this study, based on 8 systems and 37 TFTW sites around Ireland, there were significant differences in invertebrate benthos, which was largely dominated by freshwater species. The evaluation of ecological status varied significantly across sampling methods which in turn were driven by the character of the substratum.The standard kick-sample method, in riffle conditions, yielded 69 taxa, cores in intertidal soft sediments 21 taxa, and grabs in the subtidal 15 taxa. The salinity (Practical Salinity Scale) at the study sites ranged from 0 to 29.3, although all but 3 were <5, but there was a greater consistency of community composition within a single TFTW across salinities than the converse.Diversity indices followed a similar although not identical pattern, with the Shannon-Weiner index (H′) maxima being 2.24, 1.32 and 1.48 for kick samples, cores and grabs respectively. Average Score Per Taxon (ASPT) scores were much closer, ranging from 4.5 to 6.1, 3.5–6.3 and 3.6–5.2 respectively, and in general, indices which included some measure of species' tolerance performed better than those based on diversity alone, but at the cost, in core and grab samples, of a very low information base (very few species contributing to the calculation).Of those metrics assessed, only ASPT could be put forward as a WFD candidate for quality assessment.

Assessing the invasion potential of non-native branchiobdellidans: experimental studies of survival, reproduction and competition

The impact of invasive species on the recipient ecosystem can be strongly influenced by the presence of associated symbionts. It is therefore important to evaluate the likelihood of co-introduced symbiont establishment, and this requires an understanding of their life history traits. Here, we investigate survival, reproduction and competition in two non-native branchiobdellidan ectosymbionts (Xironogiton victoriensis and Cambarincola aff. okadai ) on invasive signal crayfish (Pacifastacus leniusculus ). In vivo , X. victoriensis established viable infrapopulations within 10 weeks, whereas C. aff. okadai went extinct within 2 weeks. Both X. victoriensis and C. aff. okadai deposited cocoons in vivo that hatched in 10–27 and 10–11 days, respectively. In vitro , X. victoriensis and C. aff. okadai survived for over 13 and 15 weeks respectively, although both were negatively affected by increased temperature and nitrate, and were absent from kick samples taken in the field. Only C. aff. okadai deposited cocoons in vitro , and this larger species readily predated on X. victoriensis but not vice versa . Both branchiobdellidans possess traits associated with colonisation success, including a relatively fast reproductive rate and extended off-host survival. Given its survival in vivo and known detrimental effect on signal crayfish X. victoriensis is perhaps more likely to influence host invasion dynamics, although its persistence may be affected by the presence of co-occurring symbionts.

Biomonitoring of Mucheke and Shagashe Rivers in Masvingo, Zimbabwe Using Macro-Invertebrates as Indicators of Water Quality

The traditional way of assessing water quality of water bodies is through measurement of biological, physical and chemical parameters. However, such assessments only reflect the concentration of pollutants at the time of sampling not periodic pollution events. The goal of the study was to evaluate the river health using the macro-invertebrates that are found within the Mucheke and Shagashe rivers of Masvingo City as water quality monitors. The South African Scoring System (SASS 5) was used to score using the sensitivity of macro-invertebrates to levels of pollution in the two river systems. The data collection process was carried in April 2017 at four sampling sites using the kick sampling method and results validated by testing the physical, chemical and biological characteristics of the water and comparing them with the macro-invertebrates score. Results showed that the mean sensitivity score of macro-invertebrates showed variations depending on the selected site. Sample sites B2 and A2 downstream of the two river systems show high levels pollution tolerant macro-invertebrates as compared to sites A1 and B1 that are on the upper course and have more of pollution sensitive macro-invertebrates. On validation, to a large extent the levels of pollution indicated by macro-invertebrates were found to be congruent to the levels of pollution indicated by the physical, chemical and biological parameters. The research concludes that the presence of specific types of macro-invertebrates can be used to assess the levels of pollution in Mucheke and Shagashe rivers of Masvingo City.

Macroinvertebrates on the front lines: projected community response to temperature and precipitation changes in Mediterranean streams

ABSTRACTAs temperatures rise and precipitation patterns change, approaches are needed for early detection of the effects on ecosystems. Macroinvertebrate data collected from 81 sites with multiple habitat kick sampling were compiled for this study. We used a binary logistic regression model to predict the probability of local extinction or range expansion of aquatic macroinvertebrates with changes in temperature and precipitation in watersheds of Castilla-La Mancha, Spain. Aquatic insect families from the following orders were found to be sensitive to an increase in average spring temperatures: Ephemeroptera, Plecoptera, Megaloptera, Trichoptera, Coleoptera and Diptera. Taxa in Ephemeroptera, Trichoptera, Hemiptera and Coleoptera showed negative relationships with minimum (winter) temperature, maximum spring temperature and/or precipitation. One mayfly, Caenis, exhibited a positive relationship with minimum temperature. These results indicate that these aquatic communities are expected to change significantly in the short-term, with the potential to alter stream ecosystem functioning. Mediterranean ecosystems are considered biodiversity hotspots, and biotic communities in freshwater habitats in these areas may be particularly vulnerable to projected increases in temperature and decreases in precipitation. The ability of taxa to withstand these changes will depend on resistance, resilience and dispersal capabilities of the aquatic macroinvertebrates as well as available habitat.

Detection of a new non-native freshwater species by DNA metabarcoding of environmental samples — first record of Gammarus fossarum in the UK

© 2017 The Author(s). and 2017 REABIC. We report the discovery of a non-native gammarid, Gammarus fossarum (Koch, 1836) (Crustacea, Amphipoda), in UK rivers. Gammarus fossarum is a common freshwater gammarid in many parts of mainland Europe, but was previously considered absent from the UK. Gammarus fossarum was detected in a number of UK rivers following DNA metabarcoding of a mini-barcode region of the COI gene in macroinvertebrate kick samples, and environmental DNA (eDNA) from water and sediment samples. Subsequent morphological analysis and standard DNA barcoding showed that the species could be reliably identified and separated from Gammarus pulex (Linnaeus, 1758), the most dominant and widespread native freshwater gammarid in the UK. Our data demonstrate extensive geographical coverage of G. fossarum in the UK, spanning distant river catchments. At present there is no data to confirm the likely origin of G. fossarum’s introduction. Subsequent re-examination of historic archive material shows the species to have been present in the UK since at least 1964. This study is among the first to demonstrate the potential of eDNA metabarcoding for detection of new non-native species.

Aquatic oligochaeta (Annelida: Clitellata) in extractive reserve Lake Cuniã, Western Brazilian Amazon

Abstract Oligochaeta is one of the most common and abundant taxon in continental aquatic fauna. However, knowledge of their distribution in Brazilian ecosystems is still incomplete and fragmented. Thus, the aim of this study was to develop an inventory of aquatic oligochaetes in the Extractive Reserve of Lake Cuniã in the State of Rondônia, Brazil. Collections of data were performed during the dry (August 2015) and rainy seasons (February 2016). The sediment samples were collected near the lakeside region using the kick sampling method and a kick-net sampler (mesh size of 0.25mm). This paper provides a catalog with 12 taxon from a total of 383 specimens, distributed into two families: Naididae (95.08%) and Opistocystidae (4.92%). The Pristininae subfamily was the most significant (85.68%), followed by subfamilies: Naidinae (8.36%), Tubificinae (0.52%) and Rhyacondrilinae (0.52%). In addition, some species such as Allonais inaequalis, Aulophorus furcatus, Dero nivea, Pristina synclites, Pristina menoni and Opistocysta serrata, were recorded for the first time in the Brazilian Amazon region. Therefore, the results of this study contribute to increase knowledge on the distribution of the Oligochaeta class in Brazil, particularly in the North of the country, which is so extensive and rich in water resources, but not extensively studied.

Suspended Sediment Concentration and its Impact on Aquatic Invertebrates in the Gin River, Sri Lanka

Understanding the level of suspended sediment is important for the management of aquatic fauna and flora. This study focused on the impact of suspended sediment concentration (SSC) on aquatic invertebrates in the basin of Gin river, Sri Lanka. Sixteen sampling locations along the river basin were used for data collection. Water temperature, dissolved oxygen, pH, electrical conductivity, turbidity and SSC were determined using standard laboratory methods. Aquatic invertebrates were collected using Kick sampling and stone lifting methods and they were identified using keys. Statistical analyses were done by Principal Component Analysis, factor analysis and descriptive analysis techniques. The water temperature and dissolved oxygen concentration in the Gin river basin were 25.76 ± 2.4 °C and 6.85 ± 6.1 mg/l (mean ± SD), respectively. The mean turbidity in the basin was 10.09 ± 16.1 NTU (mean ± SD). The SSC increased towards middle and lower catchments. Thirty nine different aquatic invertebrate taxa were recorded. A higher diversity of aquatic invertebrates was recorded with lower SSC in upper catchment. A negative relationship was evident between SSC and number of aquatic invertebrate species. High SSC had a negative impact on aquatic invertebrate diversity in the Gin river basin. A positive correlation was present between SSC and turbidity and therefore, a model was developed to predict SSC using turbidity data.

Macroinvertebrate taxa richness uncertainty and kick sampling in the establishment of Mediterranean rivers ecological status

Freshwater macroinvertebrates have been extensively used as environmental indicators and are the most prevalent biological group used in aquatic bioassessment in the European Water Framework Directive (WFD 2000/60/EEC), usually through several popular indices, as the Biological Monitoring Working Party (BMWP). Many of these indices are based on taxa richness, i.e. the number of taxa present in a given area, as the simplest and most common measure of biodiversity. Given the importance to the WFD of the ecological status assessment by macroinvertebrates and the consequences thereof, sampling requires careful consideration and evaluation of the associated uncertainty. In this work, carried out in a Mediterranean river, we show that after 20 sample “kicks” it was possible to estimate the true taxa richness using Clench nonlinear asymptotic models (CM). However, cumulative curves of taxa extracted with kick sampling underestimated the true number of theoretical taxa (A). In order to achieve an acceptable error a very large sample size was required, always >20 kicks. According to these criteria, sampling was clearly inefficient in most localities. The minimum effort required to achieve a significant and acceptable level of taxa richness, for 90% of A, should be between 25 and 71 kicks and for 95% of A, 52–150 kicks. Both satisfactory percentages represent a mean difference of 2 (range 0–6) and 3 (range 1–8) taxa actually not being captured from the total predicted for each locality, for 90 and 95% of the CM asymptote, respectively. This study shows that by using the 20 kicks methodology it is possible to achieve reliable true macroinvertebrate richness estimates, but the establishment of the community composition, i.e. the full taxa making up any index score, will be inaccurate to an unknown degree.

The intensity of human-induced impacts on the distribution and diversity of macroinvertebrates and water quality of Gbako River, North Central, Nigeria

The intensity of human-induced impacts on the distribution and diversity of macroinvertebrates and water quality of Gbako River, North Central, Nigeria, was evaluated monthly for 6 months using modified kick sampling techniques. Four study stations were selected along the river course (upper reaches of less human impacts through mid-reaches with relative high human impacts to lower reaches of less human impacts), designated as Stations 1, 2, 3, and 4. Water temperature (23.10–30.00 °C), flow velocity (0.10–2.40 m/s), pH, conductivity (32.00–110.00 µS/cm), and alkalinity (7.50–10.50 mg/L) were similar in all the stations sampled. However, BOD (2.20–6.00 mg/L) and nitrates (0.50–1.67 mg/L) were significantly higher (p 0.05) among the sampling stations. Stations 2 and 3 with higher human disturbance recorded lower richness when compared with the less disturbed stations (1 and 4). Furthermore, the marginally high nutrient levels (phosphate and nitrate) obtained at these stations are an indication that the water body is becoming stressed with organic input and increasing levels of anthropogenic activities. The CCA ordination revealed strong relationships between species abundances and measured environmental variables. The low relative abundance of Ephemeroptera–Plecoptera–Tricoptera (EPT) taxa indicated that the environmental conditions were relatively stressed, along the whole stations. However, the abundance of mayflies (Ephemeroptera), Coleoptera (Gyrinus, Dytiscus), and Anisoptera in all the sites studied is an indication that the sites are relatively free from gross pollution, especially at the upper reaches. Overall, relatively less human impacts in some of the study stations and the heterogeneous nature of the stations served as suitable habitat for a more diverse benthic fauna. This could be responsible for the high abundance (number of individuals) and diversity of benthic invertebrates that was recorded in this study. This study revealed that macroinvertebrate communities responded to changes in disturbance as well as water quality along the river stations.

The Colonization of Newly Built Fishponds by the Macroinvertebrate Assemblages

The succession of standing waters by aquatic macroinvertebrates is a present and insufficiently surveyed topic. This study is addressed to the issue of colonisation of newly created small standing waters. Two fishponds situated in the north of Moravia (Czech Republic) were studied. The aim of this study was to determine the character and colonisation rate of these ponds by macroinvertebrates, to evaluate the abundance, taxonomic composition and changes in composition of freshwater assemblages as a result of the fish stock influence. Basic abiotic parameters were also measured within the sampling occasions (e.g. water temperature, dissolved oxygen, conductivity, pH, total nitrogen and phosphorus concentrations). Samples of aquatic macroinvertebrates were taken monthly during the years 2012 and 2013, by kick sampling method using the hand net. The character of sampled fishponds was very similar, environmental parameters (e.g. area, substrate, depth etc.) were comparable. The colonisation of both fishponds was very fast. The pioneer colonists were mainly insect larvae (e.g. chironomids). Very low numbers of macroinvertebrates as a result of fish stock influence were recorded on both sites during the observation with the highest abundances in summer season.