Structure Of Benthic Macroinvertebrates Research Articles

Fine sediments produce tipping points in the taxonomic and functional structure of benthic macroinvertebrates in neotropical streams

Fine sediments produce tipping points in the taxonomic and functional structure of benthic macroinvertebrates in neotropical streams

Community Structure and Water Quality Assessment of Benthic Macroinvertebrates in Hongze Lake.

This study investigated the species, density, biomass and physicochemical factors of benthic macroinvertebrates in Hongze Lake from 2016 to 2020. Redundancy analysis (RDA) was used to analyze the relationship between physicochemical parameters and the community structure of macroinvertebrates. Macroinvertebrate-based indices were used to evaluate the water quality conditions in Hongze Lake. The results showed that a total of 50 benthic species (10 annelids, 21 arthropods and 19 mollusks) were collected. The community structure of benthic macroinvertebrates varied in time and space. The dominant species were Limnodrilus hoffmeisteri (L.hoffmeisteri), Corbicula fluminea (C.fluminea), Nephtys oligobranchia (N.oligobranchia). In 2016, arthropods such as Grandidierella sp. were the dominant species of benthos in Hongze Lake while annelids and mollusks dominated from 2017 to 2020, such as L.hoffmeisteri, N.oligobranchia, C.fluminea. The benthic fauna of Chengzi Lake and Lihewa District were relatively abundant and showed slight variation, while the benthic macroinvertebrates of the Crossing the water area were few and varied greatly. RDA showed that changes in benthic macroinvertebrate structure were significantly correlated with dissolved oxygen (DO), Pondus Hydrogenii (pH) and transparency (SD). The Shannon Wiener, Pielou, and Margalef indices indicate that Hongze Lake is currently in a moderately polluted state. Future studies should focus on the combined effects of various physicochemical indicators and other environmental factors on benthic communities.

The effect of oil pollution on community structure of benthic macro ‎invertebrates in the northwest of the Persian Gulf ‎ ‎(Case study: Jafari creek)‎

<p>This study evaluates the contamination levels of heavy metals and petroleum hydrocarbons in Jafari ‎Creek sediments and the effect of these pollutions on Macrobenthos in 2017. Studies to understand ‎the effect of heavy metal Cadmium, Chromium, Nickel, Lead, Selenium, Zinc, Copper, and ‎Vanadium, and 16 hydrocarbon compounds, organic material, and soil texture on the population of ‎Jafari Creek Macrobenthos in five stations along the estuary and analyzed using standard ‎procedures. The 4 identified Macrobenthos included Bivalvia with 9 species, Gastropoda with 8 ‎species, Crustacea with 7 species, and Polychaeta with 6 species totaling Macrobenthos 3645.14 per ‎square meter. The dominant class was Polychaetes (53.9%), followed by Bivalvia (23.2%), ‎Gastropoda (9.93%), and Crustaceans (15.8%), with slightly different (P<0.05), were in the second ‎and third class. Among the studied metals, zinc, chromium, and nickel had the highest ‎concentration. Among the hydrocarbons, Anthracene at station 1, Fluorene at station 2, ‎Phenanthrene and Dibenzo [A, H] Anthracene at station 3, and Fluoranthene at station 4 with a ‎concentration between <0.01- 0.091 ppm had the highest value. The highest and lowest heavy metal ‎concentrations were measured at station 4 (215.54 ± 14.58 ppm) and station 1 (102.39 ± 24.15 ‎ppm), respectively. In return, stations 1 (0.339 ± 0.074 ppm) and 4 (0.196 ± 0.078 ppm) had the ‎highest and lowest concentration of hydrocarbons, respectively. Regarding the number of identified ‎Macrobenthos, stations 3 and 2, with 1738.64 and 333.28 n/m2 had the highest and lowest numbers, ‎respectively. The class of Crustacea had a positive correlation with zinc, copper, and lead metal and ‎a negative correlation with Selenium. Polychaeta was positively correlated with cadmium and ‎vanadium. Gastropoda had a negative correlation with vanadium and chromium, a positive ‎correlation with lead and hydrocarbons, and Bivalvia correlated negatively with lead and zinc and ‎had a correlation with vanadium. Considering that the areas around Jafari Creek are an industrial, ‎petrochemical, and economic region considered one of the important catchments in the province of ‎Khuzestan, the sediments, water, and animal tissues must be periodically the analysis of heavy ‎metals and oil hydrocarbons should be considered.‎</p>

Water quality shapes the community structure of zoobenthos in rivers but only has a minor effect on the fatty acid composition of zoobenthos and salmonids

AbstractMany river ecosystems in the boreal zone have faced remarkable changes due to intensive human activities, including land‐use changes in the catchments and channelization. Recently, restoration efforts have increased, hoping to restore a more natural hydromorphology. We studied the community structure of benthic macroinvertebrates (zoobenthos) in seven rivers in Eastern Finland, using samples that covered pre‐ and post‐restoration periods, to examine how environmental metrics relate to the zoobenthos community structure, and the fatty acid (FA) composition and content of Ephemeroptera, Plecoptera, and Trichoptera nymphs and larvae. We also analyzed the FA composition and content of land‐locked salmon (Salmo salar m. sebago) in three of the rivers and brown trout (Salmo trutta) in two of the rivers. Zoobenthos communities differed significantly among most of the rivers: 24% of the differences between the zoobenthos communities were driven by water quality parameters related to the loading of terrestrial organic matter (water color, pH, and iron concentration). Temporal changes in zoobenthos communities could not be fully attributed to restorations. The FA composition of zoobenthos was mostly explained by phylogenetic origin (47%). However, especially mayfly Heptagenia sulphurea (Ephemeroptera: Heptageniidae) had variable FA composition and content among the rivers suggesting an environmental quality indicator role for this species. FA composition and content of salmonids were mostly size‐dependent (24%), but river identity also influenced their FA composition (22%). Our results indicate that water quality affects the availability of essential FAs for consumers by altering the zoobenthos community structure and their FA composition and content.

Comparative approach of the fauna diversity of benthic macroinvertebrates in a stream on ferralitic soil and equatorial climate at 2 seasons in Cameroon (Central Africa)

In order to determine the structure of benthic macroinvertebrates fauna in relation with some environmental factors, a study was carried out in the Esoa river at Nkongsamba in the Littoral region of Cameroon from January 2021 to January 2022. Physico-chemical parameters were measured according to APHA and Rodier recommendations, while benthic macroinvertebrates sampling was done out according to the multihabitat approach at a monthly frequency. The physico-chemical analyses revealed very good oxygenation of the water, a tendency of neutrality for the pH (7.79±0.8 UC) and a low and constant temperature (22.61±1.83 °C). The BMI count showed 3732 individuals, including 4 phyla, 6 classes, 14 orders and 69 families and over 80 species. Besides, the class of insects, and in particular the order of Odonata, supplanted the benthic fauna. The Esoa 2 and Esoa 3 stations recorded the highest relative abundance of BMI (37.43% and 36.99% respectively) with a predominance of pollutant taxa, notably the families of Chironomidae, Physidae, Tubificidae and Lumbricidae. On the other hand, the Esoa 1 station, with low relative abundance (25.56%), was more diversified and dominated by polluosensitive taxa, including Ephemeroptera, Plecoptera and Trichoptera. The high values of the Sӧrensen similarity index (65.62%) showed a high faunal similarity of the Esoa 2 and Esoa 3 stations. The high values of the Shannon and Weaver diversity index (4.6 bits/ind) indicated a high diversity of benthic macroinvertebrates reflecting the good ecological status of the waters of the Esoa stream.

Factors affecting the ecological habitat of Benthic macro-invertebrate assemblages in Asan wetland, Dehradun in Garhwal Himalaya

The Himalayan region has several freshwater resources, such as rivers, lakes, and wetlands. These freshwater resources have been adversely affected by environmental factors. Freshwater biological systems are defenseless against outcomes of environmental changes that might prompt the irreversible disintegration of these natural surroundings. The present study aimed to investigate the effect of biotic and abiotic factors on the Benthic macro-invertebrate assemblages of the Asan wetland, Dehradun in Garhwal Himalaya. A determination of the physico-chemical health status of the Asan wetland viz., electrical conductivity (EC), total dissolved solids (TDS), biochemical oxygen demand (BOD), and nutrients parameters like nitrogen, potassium, and phosphorus were investigated during this study. Three sampling sites (Site 1, Site 2 and Site 3) of wetland were selected and the water samples were collected seasonally, i.e., summer, winter, and monsoon from April 2021-March 2022. Maximum values of EC(163.75 µS/cm), TDS (232.78 (mg/l), alkalinity (141.20 mg/l) and pH(7.8) were recorded in the monsoon season (June-September) and minimum values of EC( 135.80µS/cm), TDS (196.80 (mg/l), alkalinity (119.80mg/l) and pH(7.2) were recorded in the winter season (November–February). An overall total of 18 macrobenthos genera belonging to four classes was identified. Maximum communities of macrobenthos were observed during the winter and minimum communities during the monsoon season. Canonical correspondence analysis (CCA) was used to determine whether microbenthic genera and habitat ecological parameters and showed a positive or negative correlation. Thus, the present study contributed to the status of various factors and their impacts on the Benthic macro-invertebrate structure of the Asan wetland.

Does experimental seaweed cultivation affect benthic communities and shorebirds? Applications for extensive aquaculture.

Extensive seaweed aquaculture is a growing industry expected to expand globally due to its relatively low impact and benefits in the form of ecosystem services. However, seaweeds are ecosystem engineers that may alter coastal environments by creating complex habitats on previously bare mudflats. These changes may scale up to top-consumers, particularly migratory shorebirds, species of conservation concern that regulate trophic webs at these habitats. Understanding how habitats are transformed and how this affects different species is critical to direct ecological applications for commercial seaweed management. We experimentally assessed through a Before-After Control-Impact design the potential changes exerted by Gracilaria chilensis farming on bare mudflats on the abundance, biomass, and assemblage structure of benthic macroinvertebrates, and their scaled-up effects on shorebirds' habitat use and prey consumption. As predicted, experimental cultivation of G. chilensis significantly affects different components of biodiversity that scale-up from lower to upper trophic levels. The total biomass of benthic macroinvertebrates increased with seaweed cultivation and remained high for at least 2 months after harvest, boosted by an increase in the median size of polychaetes, particularly Nereids. Tactile-foraging shorebirds tracked these changes at the patch level increasing their abundance and spending more time foraging at seaweed cultivated plots. These results suggest that seaweed farming has the potential to impact shorebird populations by favoring tactile-foraging species which could lead to a competitive disadvantage to species that rely on visual cues. Therefore, the establishment of new seaweed farms in bare mudflats at key sites for shorebirds must be planned warranting habitat heterogeneity (i.e., cultivated and non-cultivated areas) at the landscape level and based on a previous experimental approach to account for local characteristics. Fostering properly designed extensive seaweed farming over other aquaculture industries with greater negative environmental impacts would provide benefits for human well-being and for ecosystem functions.

Ecological structure of aquatic macroinvertebrate communities in the Hauts Plateaux of Northeast Algeria.

Aquatic macroinvertebrates are integral parts of functioning wetlands, inhabiting a diversity of aquatic ecosystems where communities are spatially structured. Macroinvertebrates of some Mediterranean regions such as North Africa are still not well studied. Here, we study the community structure of benthic macroinvertebrates in four different types of lotic and lentic wetlands in the semiarid Haut Plateaux of Northeast Algeria. Macroinvertebrates and 06 physicochemical parameters were sampled in 12 sites belonging to four types of habitats (lotic river, lentic river, dams, and sebkha [saline lentic water body]) during January-December 2021. Eventually, the character lentic-lotic was the most important variable affecting the affecting invertebrate communities in the Mediterranean region. The results revealed that sebkha and dams had a lower Shannon index than lentic and lotic rivers. Non-metric multidimensional scaling analysis showed a strong overlap between the community composition in lotic and lentic sites . Howeverin the three types of aquatic groups lentic river, dam and lotic habitats showed a strong overlap between the community whereas sebkha was markedly separated. Redundancy analysis showed that water velocity and pH, were the main drivers of community structure of macroinvertebrates, revealed a strong effect with pH (F1,8=4.15, P = 0.001) and water velocity (F1,8= 3.22, P = 0.002) , separating lotic communities from those that inhabited dams, lentic rivers, and sebkhas. As conclusion, this study contributes to the better understanding of the community structure of macroinvertebrates in semiarid North Africa where wetlands have been experiencing high anthropogenic disturbance.

Environmental factors are the major drivers of macroinvertebrate assemblage structure in southern Brazilian coastal lakes

AbstractCoastal freshwater lakes are distinctive landscape features in South America, and benthic macroinvertebrates are key to their ecological functioning. Identifying the main factors driving the assemblage structure of benthic macroinvertebrate is thus important for the development of management strategies in these ecosystems. However, studies on the drivers of macroinvertebrate assemblages are scarce in subtropical coastal lakes of the Neotropical region. Here, we evaluated the role of environmental (morphometric and water chemistry variables) and spatial factors in the assemblage structure of benthic macroinvertebrates in 36 coastal freshwater lakes in Brazil from 2008 to 2015. Macroinvertebrate family richness increased with ammonium, pH and water transparency, and decreased with nitrate content (slope ≈1 for all significant variables). Environmental factors explained most of the variation in macroinvertebrate composition (16%) compared to spatial ones (3.4%). In specific, Dugesiidae, Hydrobiidae, Corbiculidae, Sphaeromatidae, Noteridae, Hydropsychidae, Culicidae and Ceratopogonidae predominated in lakes with lower conductivity (<100 μS/cm) and higher water transparency (>1 m). Spatial factors summarized differences in macroinvertebrate assemblages between isolated and connected lakes. Although none of the lakes studied are directly impacted by organic pollution, our results suggest that benthic macroinvertebrate assemblages in subtropical coastal lakes are mostly structured by water chemistry, likely reflecting the major trends in land use along the study region (transition from agriculture to urban areas). We recommend that the conservation of macroinvertebrate biodiversity in southern Brazilian coastal lakes focus on the monitoring of water chemistry factors associated with human‐based land use.

Community structure of benthic macroinvertebrates in native and introduced mangroves of northern Beibu Gulf, China: Implication for restoring mangrove ecosystems

Introduced mangroves are widely used to restore mangrove ecosystems in South China. Results of potential impacts on indicative benthic macroinvertebrates are divergent. We explored the community structure of benthic macroinvertebrates in the mangrove ecosystem of northern Beibu Gulf, China across four habitats: native Avicennia marina mangrove, introduced Laguncularia racemosa mangrove, native-introduced mixed mangrove, and unvegetated intertidal flat. Based on the Hill number, community structure was estimated from the dimensions of estimated species richness, diversity, evenness, and species composition similarity. Benthic macroinvertebrates in the unvegetated flat significantly differed from the other three assemblages in mangroves; introduced L. racemosa mangrove had relatively distinct benthic macroinvertebrate assemblage from the native A. marina and the mixed mangroves, with lower species richness and similarity but higher diversity and evenness. Considering the lack of unanimous conclusion of potential impact on benthic macroinvertebrates under complex species interactions, native mangroves should be of top priority in ecosystem restoration.

Macroinvertebrate-based index of biotic integrity for assessing the ecological condition of Lake Wanchi, Ethiopia

Background: Lake Wanchi is one of the Ethiopian lakes that have huge ecological, socio-economic and aesthetic value. This study was conducted to assess the ecological condition of Lake Wanchi using the macroinvertebrate-based index of biotic integrity between September 2016 and should 2017.Methods: Four sampling sites (LWS 1, LWS 2, LWS 3, and LWS 4) were purposively selected. A rapid bioassessment protocol criterion was accustomed to categorize the sites. About 1249 macroinvertebrate individuals were collected using the D-frame net with a mesh size of 500µm. Physico-chemical analysis was also done to assess the link between the benthic macroinvertebrate structure and environmental factors within the system.Results: The benthic index of biotic integrity ranged from 12.54 to 100 and also the sites were categorized into three quality ranks: LWS 1 and 3 as fair, LWS 2 as good, and LWS 4 as very good. Conclusions: The study confirmed that Lake Wanchi was largely influenced by agricultural and other anthropogenic factors. This study concluded that the benthic index of biotic integrity is an appropriate tool for water quality and ecological assessment in the lakes.

Seasonal variation in the metacommunity structure of benthic macroinvertebrates in a large river-connected floodplain lake

To improve our understanding on the temporal aspects of metacommunity structure, we focused on benthic macroinvertebrates collected seasonally (i.e., wet, drying, dry and rewetting seasons) in Dongting Lake, a large subtropical floodplain lake in China. We employed the elements of metacommunity structure (EMS) framework and variation partitioning to examine whether metacommunity structure and its underlying mechanisms vary among seasons with distinct biotic and abiotic features. We found gradual shifts in the main assembly mechanisms throughout the year, from apparent spatial structuring (potentially indicative of mass effects) in the wet season to more environmental filtering dynamics in the dry season. When the degree of connectivity was high in the wet season, the benthic metacommunity was characterized by nested structure associated with clumped species loss, and was shaped mainly by spatial processes. However, quasi-Clemensian structure was assigned to metacommunities in the transitional seasons with intermediate connectivity, during which environmental variables were more important than spatial factors in describing community structure. When the degree of connectivity was low in the dry season, the benthic metacommunity displayed Clementsian structure, which was configured solely by environmental variables. The rapid shifts in metacommunity dynamics between seasons mainly result from the considerable changes in the hydrological conditions of Dongting Lake, as the studied system varies from lacustrine to fluvial phases within a single year. Taken together, our results revealed that taking temporal aspects into account gives a better insight into metacommunity organization, especially when the studied systems embrace remarkable variability in hydrological regimes.

Altitudinal distribution of the functional feeding groups of aquatic macroinvertebrates using an ecological network in Andean streams

Introduction: Analysis of functional feeding groups (FFG) in aquatic macroinvertebrates is important in understanding the structure, function, and dynamics of ecological processes ecosystems. Modularity refers to the degree of compartmentalization of food webs and varies between -1 and 1. A network with a modularity value close to 1 is resilient to disturbances and can be interpreted as an indicating factor for the stability of communities. Objective: In this study, we analyzed the trophic structure of benthic macroinvertebrates in La Nitrera stream, the San Juan River, and the Cauca River. Methods: The study was supported by ecological networking techniques using Gephi software. We studied nine sites in dry, rainy, and transition seasons in 2017 and 2018, monitoring changes in the altitude gradient. At each of the sites, the organisms were captured and determined, and physicochemical and hydraulic information was obtained. Results: The variance component analysis allowed to explain the variability of the data by relating the following environmental variables: FFG, diversity, richness, modularity, season, and time. Simple multifactorial ANOVA indicated that significant changes in FFG were associated with altitude, and modularity to time. The allocation of the FFG was done by stomach analysis and secondary information. Conclusion: The transition season had the highest modularity, possibly due to the recolonization of some biotopes caused by the decrease in riverbed velocity. La Nitrera and San Juan presented higher values than the Cauca, which may indicate that the altitudinal change and velocity of water currents affects the compartmentalization of the network.

Effects of littoral zone utilization on benthic macroinvertebrate community structure: A case study of Lake Hongze

湖滨带是湖泊与陆地生态系统间非常重要的生态过渡带，能够保障周围生态系统结构的完整以及功能的正常发挥.随着湖滨带被持续开发与利用，人为干扰对湖滨带的影响逐渐增强.大型底栖动物是淡水生态系统的重要生物类群之一，也是物质循环和能量流动的主要环节，起着承上启下的关键作用.为了解湖滨带开发利用对大型底栖动物群落结构的影响，2020年8月对洪泽湖湖滨带49个样点的大型底栖动物进行调查.共采集到大型底栖动物49种，隶属3门7纲17目26科44属，各样点大型底栖动物的密度差别较大，介于6.67~1386.67 ind./m²之间，整体上呈现西北高，东南低的趋势.相似性分析结果表明，河口型湖滨带和大堤型湖滨带与其他类型湖滨带差异显著，而围网型、圈圩型和光滩型3种湖滨带类型之间的大型底栖动物群落差异均不显著.相似性百分比分析结果表明，腹足纲的环棱螺属是造成不同湖滨带类型差异的主要物种.典范对应分析结果表明，悬浮物（SS）、溶解态总氮、pH、透明度（SD）、浊度、水生植物盖度和扰动指数对大型底栖动物群落有显著影响.考虑不同湖滨带宽度的开发利用情况，发现湖滨带开发利用200 m范围内，物种-环境解释率最高，说明200 m湖滨带范围内的开发利用情况对大型底栖动物的影响最大，对湖滨带200 m范围内的开发利用应该加强管控.结构方程模型表明湖滨带开发利用主要通过影响水生植物盖度、总氮、硝态氮、叶绿素a、SS、SD等进而影响大型底栖动物，且围网也会直接影响大型底栖动物群落结构.;Littoral zone is of great importance for lake and terrestrial ecosystems, which can ensure the surrounding ecosystem structure integrity and normal functional performance. With the continuous development and utilization, the impact of human disturbance on the littoral zone is gradually increasing. Benthic macroinvertebrates are important components of freshwater ecosystems. It is the main link between nutrient cycling, and energy flow and plays a key role in connecting the food web. In order to understand the impact of the littoral zone utilization on benthic macroinvertebrate community structure, a field survey was conducted at 49 sample sites in the littoral zone of Lake Hongze in August 2020. A total of 49 species were collected, belonging to 3 phyla, 7 classes, 17 orders, 26 families and 44 genera. The abundance of benthic macroinvertebrates at each site varied greatly, ranging from 6.67 to 1386.67 ind./m². Generally speaking, the abundances was higher along the northwestern coastline, but lower along the southeastern shoreline. The results of similarity analysis showed that there were significant differences among estuarine littoral zone, levee littoral zone and other types of the littoral zone, but there were no significant differences in benthic macroinvertebrate communities among purse seine type, circle polder type and light beach type. The results of similarity percentage analysis showed that Bellamya spp. is the main species causing the discrepancy among different littoral zone types. Canonical correspondence analysis showed that suspended solid (SS), total dissolved nitrogen (TDN), pH, transparency (SD), turbidity, aquatic plant coverage and Em-5year had significant impacts on the benthic macroinvertebrate communities. When the width of the littoral zone was 200 m, the variation in the species-environment relationships was the highest, indicating that the benthic macroinvertebrates within the 200 m littoral zone of Lake Hongze were the most affected. The utilization within 200 m littoral zones should be controlled and monitored. The structural equation model shows that the littoral zone utilization mainly indirectly affects benthic macroinvertebrates by affecting aquatic plant coverage, total nitrogen, nitrate nitrogen, chlorophyll-a, SS and SD, and the purse seine will also directly affect the community structure of benthic macroinvertebrates.

The Colonization of a Cold Spring Ecosystem by the Invasive Species Potamopyrgus antipodarum (Gray, 1843) (Gastropoda: Tateidae) (Southern Poland)

Springs are unique aquatic environments that support specific biota, including endemic species and rare species listed in Red Lists. Due to their usually small size, springs are highly sensitive to disturbance. Many of them are threatened by aquifer depletion, contamination, surface-water diversion, livestock trampling, recreation, and invasive species. The aim of this study was to assess the colonization success of the invasive New Zealand mud snail (Potamopyrgus antipodarum) in a cold spring ecosystem in southern Poland. In Europe, this species has recently been added to the top “hundred worst” alien species due to its impact on invaded ecosystems. The study was carried out in two areas of the spring ecosystem—in the springhead and the springbrook—over a four-year period. Potamopyrus antipodarum dominated the benthic macroinvertebrate communities in both areas of the spring ecosystem. Nevertheless, its abundance in the springbrook was significantly greater, and increased noticeably during subsequent years compared to that in the springhead. The populations of P. antipodarum were exclusively composed of females. Smaller-sized New Zealand mudsnails were more abundant near the spring’s source than at the second site. The females at the springhead became fecund at sizes as small as 3.7 mm (the number of embryos was between 0 and 37), while at the springbrook, embryos were found in snails as small as 3.4 mm (the number of embryos was between 0 and 42). Our results suggest that the lower water temperature at the springhead may limit the population size of P. antipodarum, thus making its density too low to be able to affect the community structure of benthic macroinvertebrates, including the spring snail Bythinella cf. austriaca.

In Situ Effects of a Microplastic Mixture on the Community Structure of Benthic Macroinvertebrates in a Freshwater Pond.

Benthic communities contain some of the most threatened organisms in aquatic habitats due to different anthropogenic pressures. The high abundance of microplastics in sediments will continue to increase in the future, further increasing the probability of interactions between macroinvertebrates and microplastics. In the present study, a benthic community in a relatively pristine shallow pond was exposed either to an environmentally relevant high concentration of a microplastic mixture of 80 g m-2 in the sediment, or a control sediment, without the addition of microplastics. The mixture of microplastics contained irregularly shaped polyethylene, polyvinyl chloride, and polyamide in a ratio of 50:25:25%, respectively. The in situ experiment lasted for 100 d. The total number of taxa that colonized the microcosms was 22 (17 in the control and 18 in the microplastic treatment), and the colonization was not affected by the treatment. The most dominant group within the macroinvertebrate community was the dipteran family Chironomidae, in both the control and the microplastic treatment. No significant differences in the abundance and biomass at a community level were recorded between the groups by permutational multivariate analysis of variance (F = 0.993, p = 0.456 and F = 0.344, p = 0.797, respectively). The mixture of microplastics did not influence the abundance or biomass of the functional feeding groups (F = 1.810, p = 0.137 and F = 0.377, p = 0.736, respectively). The species richness, species abundance, species biomass, Shannon's diversity index, and Simpson's index of diversity showed no statistically significant differences between the control and treatment groups. Czekanowski's quantitative similarity index indicated that 84% of the community remained unaffected after microplastic exposure. Environ Toxicol Chem 2022;41:888-895. © 2021 SETAC.

Influence of Environmental Characteristics on the Community Structure of Benthic Macroinvertebrates in Stream-type Waterways Constructed at Upper Reaches of Guem River

Influence of Environmental Characteristics on the Community Structure of Benthic Macroinvertebrates in Stream-type Waterways Constructed at Upper Reaches of Guem River

Water Quality And Benthic Macroinvertebrates Of Tropical Forest Stream In South-West Region, Cameroon

A study was carried out in Ndongo stream, located in Buea, from May to October 2017, to assess the water quality and evaluate the structure of benthic macroinvertebrates. Physicochemical analysis showed that water from Ndongo was well oxygenated (82.21 ± 6.59 %), slightly acidic (pH=6.82 ± 0.22 UC) and alkaline with low quantities of nitrogen compound (2.9 ± 3.57 mg/L NO3+; 0.02 ± 0.02 mg/L NO2– and 0.89 ± 1.78 mg/L NH4+). Regarding the biology of macroinvertebrates, a total of 2058 individuals were collected and identified into 4 phyla, 5 classes, 11 orders, 32 families and belonging to 44 genera. The Shannon & Weaver and Pielou evenness reveal that the benthic macroinvertebrates were more diversified in upstream.

Effects of riparian vegetation removal on the functional feeding group structure of benthic macroinvertebrate assemblages

The present study aims to verify possible changes in the functional feeding group (FFG) structure of benthic macroinvertebrates related to changes in headwater streams riparian vegetation. Streams with this vegetation fully present (forested), present only on one bank (intermediate) and absent (pasture) were studied. In general, there was low abundance of shredders in all streams, a typical pattern found in neotropical streams. The FFG abundance analysis indicated differences only for the gathering collectors’ group, with the abundance in the forested streams significantly smaller than in the other two profiles. The FFG richness analysis did not indicate significant differences. The RDA analysis made with the environmental and FFG abundance data showed a strong relationship of some habitat characteristics related to environmental quality loss, such as higher values of fine substrate and vegetation on the banks, with the abundance of gathering collectors, filtering collectors and predators in streams with the riparian vegetation partially or totally removed. The initial premise of higher FFG complexity in streams with riparian vegetation was not confirmed. In addition, the results showed a high predators richness, probably favored by the high prey and ambush shelter availability, and the latter represented by vegetal debris and coarse substrate at the forested streams bottom or herbaceous vegetation on the altered streams banks. The functional approach of the present study allowed to verify the advantage of benthic macroinvertebrates use as habitat quality ecological indicators, when analyzed together with environment variables directly or indirectly related to feeding mechanisms.

Taxonomic Diversity and Structure of Benthic Macroinvertebrates of Taabo Lake (Basin of Bandama; Ivory Coast)

The taxonomic diversity and structure of benthic macroinvertebrates of Taabo Lake (Ivory Coast), from November 2017 to October 2018 were evaluated. Water quality parameters, such as temperature (T °C), water transparency (cm), dissolved oxygen (mg.L-1), pH, turbidity (NTU), electrical conductivity (EC, µS.cm-1) were measured in situ using a multi-parameter probe HANNA, from four sampling points (littoral and sub-littoral zones) in Taabo Lake. Benthic macroinvertebrates sampling were collected by using Van veen in stainless steel. A total of 63 benthic macroinvertebrates taxa belonging to 23 Families, 8 Orders, 2 Classes and 2 Phylums (Molluscs and Arthropods) were identified. The most abundant of benthic macroinvertebrates were Mesogastropoda (66%) represented in all sampling points. They were followed by Diptera (25%), Odonata (3%), Ephemeroptera (3%), Basommatophora (2%), Heteroptera (1%), Lepidoptera and Coleoptera (less than 1%). The values of diversity indices of benthic macroinvertebrates collected in Taabo Lake showed no significant variations between sampling points.