Macroinvertebrate Abundance Research Articles

Effects of inundation on water quality and invertebrates in semi-arid floodplain wetlands

Floodplain wetlands play a significant role in the storage of sediment and water and support high levels of nutrient cycling that is driven by intermittent inundation. In regulated rivers, there is often a reduction in the frequency and duration of inundation and managed floodplain inundation is used as a tool to help restore wetlands. It is important to quantify the outcomes of re-introducing water to floodplain wetland systems. We examined the effects of environmental floodplain watering on water quality and three groups of invertebrates, including benthic and pelagic microinvertebrates and macroinvertebrates, in two wetlands systems on the Gwydir River system in the north of the Murray-Darling Basin. We hypothesised that a wetland inundated for longer periods of time would have altered water quality and support a greater richness and abundance of invertebrates, thus altering their assemblage structures. Water quality and the assemblage structure of all three invertebrate groups in the wetlands was significantly influenced by the time since connection (TSC) to their rivers and therefore the length of inundation. However, the response of water quality and the microinvertebrate assemblages to TSC differed between the two wetlands. Water quality was affected by an increase in six variables, including the nutrient TN and a decrease in the nutrient SRP. Microinvertebrate abundance was positively associated with TSC, but the abundance of macroinvertebrates was not. The relationships demonstrated between TSC and invertebrates indicate that the duration of inundation is important in maintaining the ecology and food webs in these and other semi-arid floodplain wetlands.

Ecosystem effects of invasive crayfish increase with crayfish density

Abstract The nature and extent of effects of increasing densities of non‐native species on stream ecosystems remain poorly understood. Non‐native crayfish are among the most invasive aquatic species and we hypothesised that, in temperate streams, the extent of trophic modification increases with non‐native crayfish density. Instream flow‐through mesocosms in the River Lune, north‐east England, were used over a 47‐day period in summer to measure density effects of invasive signal crayfish Pacifastacus leniusculus on different ecosystem components (benthic fish, macroinvertebrates, algal biomass, and leaf litter breakdown). Effects were measured through three density treatments (low, medium, and high; four, eight, or 12 crayfish with five bullhead Cottus perifretum per 1.5 m2) and two control (crayfish and fish absent; crayfish absent and benthic fish present) groups. Impacts of crayfish on macroinvertebrates (density, taxonomic composition), fish (growth, diet), algal standing stock, and decomposition rates increased with crayfish density. Direct effects of increased crayfish density were more important than indirect trophic cascade effects. Despite similar invertebrate abundance and richness across enclosures before introducing crayfish and bullhead, they differed significantly from controls at the end of the study, with >80% reduction in macroinvertebrate abundance recorded in the high‐density group. Stable isotope (δ15N, δ13C) analysis showed that the trophic niche of bullhead, but not signal crayfish, changed when the species were in sympatry. Bullhead in treatment enclosures occupied a lower trophic position in the food web than those from the control group. Bullhead in the high‐density group lost 4.2% of body mass over the study period, confirming the existence of resource competition. Leaf litter break down was 59.2% faster, and algal biomass was 91.4% lower in the treatment with the highest crayfish density compared to the control without study animals. This study indicates that signal crayfish, even at a low density, can strongly alter multiple ecosystem components in streams, and emphasises the need for minimising the spread of invasive crayfish within and between streams.

Improved management of farm dams increases vegetation cover, water quality, and macroinvertebrate biodiversity.

In many farming landscapes, aquatic features, such as wetlands, creeks, and dams, provide water for stock and irrigation, while also acting as habitat for a range of plants and animals. Indeed, some species threatened by land‐use change may otherwise be considerably rarer—or even suffer extinction—in the absence of these habitats. Therefore, a critical issue for the maintenance of biodiversity in agricultural landscapes is the extent to which the management of aquatic systems can promote the integration of agricultural production and biodiversity conservation. We completed a cross‐sectional study in southern New South Wales (southeastern Australia) to quantify the efficacy of two concurrently implemented management practices—partial revegetation and control of livestock grazing—aimed at enhancing the vegetation structure, biodiversity value, and water quality of farm dams. We found that excluding livestock for even short periods resulted in increased vegetation cover. Relative to unenhanced dams (such as those that remained unfenced), those that had been enhanced for several years were characterized by reduced levels of turbidity, nutrients, and fecal contamination. Enhanced dams also supported increased richness and abundance of macroinvertebrates. In contrast, unenhanced control dams tended to have high abundance of a few macroinvertebrate taxa. Notably, differences remained between the macroinvertebrate assemblages of enhanced dams and nearby “natural” waterbodies that we monitored as reference sites. While the biodiversity value of semilotic, natural waterbodies in the region cannot be replicated by artificial lentic systems, we consider the extensive system of farm dams in the region to represent a novel ecosystem that may nonetheless support some native macroinvertebrates. Our results show that management interventions such as fencing and grazing control can improve water quality in farm dams, improve vegetation structure around farm dams, and support greater abundance and diversity of aquatic macroinvertebrates.

Impact of Seasonal Changes in the Abundance of Benthic Macroinvertebrates & Physico-Chemical Conditions of a Major River in Western India

The study is focused on the seasonal assessments of riverine water quality and the distribution of benthic macroinvertebrates community at Mahisagar river, India. 27 physiochemical indicators and benthic macroinvertebrates community were identified as per aquatic ecological health criteria to evaluate water quality. Indices like Margalef’s species richness Fisher’s alpha diversity, Saprobic score, Diversity score were calculated to understand the effect of seasonal changes on the pollution tolerance levels of benthic macroinvertebrates. PCA was performed for identifying major pollutants. Applications of such statistical tools and scores, a solution toward the sustainable management of the ecological health of a river can be developed.

Diversity and abundance of soil macroinvertebrates along a contamination gradient in the Central Urals, Russia.

BackgroundSince the late 1980s, long-term monitoring of terrestrial ecosystems in metal-contaminated areas near the Middle Ural Copper Smelter has been carried out in the Central Urals. As a part of these monitoring programmes, the data on species diversity, community composition and abundance of soil macroinvertebrates continue to be gathered.New informationThe dataset (available from the GBIF network at https://www.gbif.org/dataset/61e92984-382b-4158-be6b-e391c7ed5a64) includes a 2004 census for soil macroinvertebrates of spruce-fir forests along a pollution gradient in the Central Urals. The dataset describes soil macrofauna’s abundance (the number of individuals per sample, i.e. the density) and community structure (list of supraspecific taxa, list of species for most abundant taxa and supraspecific taxa or species abundance). Seventeen sampling plots differed in the levels of toxic metal (Cu, Zn, Pb, Cd and Fe) soil contamination from air emissions of the Middle Ural Copper Smelter (heavily polluted, moderately polluted and unpolluted areas). The dataset consists of 340 sampling events (= samples corresponding to upper and lower layers of the 170 soil monoliths) and 64658 rows (2907 and 61751 for non-zero and zero density of taxa, respectively). Arachnida (Araneae and Opiliones), Carabidae (imagoes), Elateridae (larvae), Chilopoda, Diplopoda, Gastropoda, Staphylinidae (imagoes) and Lumbricidae were identified to species level. In contrast, Mermithida, Enchytraeidae, Lepidoptera larvae, Diptera larvae, Hemiptera, Hymenoptera and some other insects were identified to family or order levels. In total, 8430 individuals of soil macroinvertebrates were collected in two soil layers (organic and organic-mineral horizons), including 1046 Arachnida (spiders and harvestmen), 45 Carabidae, 300 Elateridae, 529 Myriapoda, 741 Gastropoda, 437 Staphylinidae, 623 Lumbricidae and 4709 other invertebrates. The presence-absence data on each taxon are provided for each sampling event. An overwhelming majority of such absences can be interpreted as “pseudo-absences” at the scale of sampling plots or study sites. The dataset contains information helpful for long-term ecotoxicological monitoring of forest ecosystems and contributes to studying soil macrofauna diversity in the Urals.

Distribution and diversity of benthic macroinvertebrates in the Mohlapitsi River, South Africa

Freshwater ecosystems are facing degradation from human activities in the form of alterations of flow regimes, changes in land-use, and intensive water abstraction, in turn generating adverse effects on biodiversity and ecological functionality. Efficient assessment of river/stream ecosystem response to such anthropogenic changes is urgently needed. Many human activities that have an effect on water quality and river health are increasing along the Mohlapitsi River, which used to be one of the rivers with good water quality in South Africa. The aim of the study was to assess spatial variation in macroinvertebrate assemblages in relation to water quality of the Mohlapitsi River. A combination of canonical correspondence analysis and univariate analyses were used to examine the macroinvertebrate assemblages at six different sites of the Mohlapitsi River. The spatial difference in macroinvertebrate abundance was mostly related to changes in water quality. The number of taxa and the diversity of macroinvertebrates remained relatively high across the river as compared to other rivers in the Olifants River System. The midstream and downstream sites were mostly dominated by macroinvertebrates tolerant to disturbance/pollution. The most abundant family was the Thiaridae (about 60%) and mainly occurred in the midstream and downstream sites of the river (more disturbed sites). The study showed a higher evenness index in the upstream than the midstream and downstream sites which is an indication of good water quality at the upstream sites of the river. The results suggest that the river is being subjected to a moderate environmental pollution, which requires continuous assessment and monitoring to determine causes and initiate remedial measures.

Using biodiversity response for prioritizing participants and service provisions in a payment-for-water-storage program in the Everglades basin

Hydrological changes can lead to biodiversity responses that are complex and challenging to quantify. We present a framework that uses biodiversity as a criterion to address “where to buy” and “how much to buy” in a payment-for-environmental-services (PES) program focused on water storage service in the Everglades basin, USA. The PES program was designed to pay for added water storage on private cattle ranchlands by raising the spillage level in drainage control structures to reduce surface flows. We predicted that increased hydration of previously drained wetlands would benefit biodiversity, a previously unquantified but desirable co-benefit of the original program, and that a PES program offering bundled services (e.g., storage and biodiversity) can better achieve restoration goals. We quantified desirable biodiversity services (abundance of native flora and fauna such as cover of wetland and forage plants, and abundance of fishes, amphibians, and macroinvertebrates), dis-services (e.g., abundance of invasive plants and mosquitos), and hydrologic signatures (e.g., wetland water depth, inundation area and duration) at four ranches to develop eco-hydrological relationships (models) between hydrological changes and biodiversity responses. Next, a hydrologic model (MIKE-SHE/MIKE-11) was used to predict surface and subsurface water levels and flows and resulting wetland hydrologic signatures for 13 water storage alternatives on the ranches, which were used as example PES proposals. A decision-support-system (DSS) was developed to integrate (i) storage predicted by the hydrologic model, (ii) biodiversity responses predicted by eco-hydrologic models, and (iii) a user-defined preference scheme to assign importance weights to storage, biodiversity, and implementation cost. The DSS calculated a cumulative score for ranking PES proposals. By considering desirable services and dis-services, stakeholders can decide on their preferred level of services, e.g., buyer(s) may settle for less storage if there is a gain in desirable biodiversity. The DSS can identify trade-offs among services, helping stakeholders negotiate.

The Environmental Effects of the Innovative Ejectors Plant Technology for the Eco-Friendly Sediment Management in Harbors

A sediment bypassing plant based on innovative jet pump, ejectors, has been tested in the first-of-a-kind demo application at the harbor of Cervia (Italy, Northern Adriatic Sea). The ejector is a jet pump aimed to reduce sediment accumulation in navigation channels and coastal areas. Herein we present results of the first study assessing the potential ecological effects of the ejectors plant. Sediment characteristics, benthic, and fish assemblages before and after the plant activation have been analyzed in the putatively impacted (the sediment removal and discharge) areas and four control locations, one time before and two times after plant activation. Ejectors plant operation resulted in a reduction of the mud and organic matter content in the sediment, as well as in changes in shell debris amount in the impacted areas. Abundance and species richness of benthic macroinvertebrates, initially reduced in the impacted areas, probably due to the previous repeated dredging, returned to higher values during demo plant continuous operation. Higher diversity of fish fauna was observed in the study area during plant operation period. Observed dynamics of the ecological status of the marine habitat suggest that an ejectors plant could represent an eco-friendly solution alternative to dredging operations to solve harbor siltation problems.

Impacts of wastewater treatment plants on benthic macroinvertebrate communities in summer and winter

Treated effluent from municipal wastewater treatment plants (WWTPs) is a major source of contamination that can impact population size, community structure, and biodiversity of aquatic organisms. However, because the majority of field research occurs during warmer periods of the year, the impacts of wastewater effluent on aquatic communities during winter has largely been neglected. In this study, we assessed the impacts of wastewater effluent on aquatic benthic macroinvertebrate (benthos) communities along the effluent gradients of two WWTPs discharging into Hamilton Harbour, Canada, during summer and winter using artificial substrates incubated for 8 weeks. At the larger of the two plants, benthic macroinvertebrate abundance was higher and diversity was lower at sites downstream of the outfall compared to upstream sites in both seasons. Whereas at the smaller plant, the opposite was observed, abundance increased and diversity decreased with distance from the outfall in both seasons. While the impacts of wastewater on benthic communities were largely similar between seasons, we did detect several general seasonal trends – family diversity of macroinvertebrates was lower during winter at both WWTPs and total abundance was also lower during winter, but only significantly so at the smaller WWTP. Further, benthic macroinvertebrate community composition differed significantly along the effluent gradients, with sites closest and farthest from the outfall being the most dissimilar. Our contrasting results between the WWTPs demonstrate that plants, with different treatment capabilities and effluent-receiving environments (industrial/urban versus wetland), can dictate how wastewater effluent impacts benthic macroinvertebrate communities.

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.

Different kelp species support unique macroinvertebrate assemblages, suggesting the potential community‐wide impacts of kelp harvesting along the Humboldt Current System

Abstract Kelp forests provide habitat for myriad species yet remain poorly studied in some ecoregions, including where there is increasing interest in commercial kelp harvesting for the lucrative alginate industry. To identify indicators for monitoring the impacts of kelp harvesting, the structure and composition of macrobenthic invertebrate assemblages associated with large brown macroalgae, Eisenia cokeri, Lessonia trabeculata and Macrocystis pyrifera, from the Humboldt Current System of Peru were determined. Within kelp habitats two distinct habitats were sampled: (a) adult kelp holdfasts; and (b) the benthos adjacent to the kelp sporophyte (hereafter under‐canopy rock). For each sample, organisms were identified, enumerated and weighed. Totals of 108, 102 and 113 different species were found associated with Eisenia cokeri, M. pyrifera and L. trabeculata, respectively comprising distinct assemblages associated with each kelp forest. Both habitat types (holdfasts and under‐canopy rock) supported diverse, but different, macroinvertebrate assemblages, with richness, abundance and functional trophic groups in general higher in holdfasts compared with on under‐canopy rock. Lastly, macroinvertebrate abundance, biomass, and species richness significantly increased with holdfast size. Results confirm that each kelp species is unique in terms of associated assemblage composition and indicate that kelp harvesting for the alginate industry may have large impacts. We suggest that these effects on associated biodiversity should be incorporated within kelp harvesting management plans. We suggest that holdfast diameter is a good ecological indicator as reductions in holdfast size across the population will indicate a decline in the diversity of macroinvertebrates that are important food sources for higher order organisms. We therefore suggest that monitoring studies include morphological measurements as well as measurement of kelp density.

Diversity and Abundance of Macroinvertebrates in Kaakkaithivu coastal waters, Jaffna estuary

Diversity and Abundance of Macroinvertebrates in Kaakkaithivu coastal waters, Jaffna estuary

Floating Littoral Zone (FLOLIZ): A solution to sustain macroinvertebrate communities in regulated lakes?

Artificial water-level fluctuations (WLF) seriously threaten the biodiversity and functioning of littoral zones in lake ecosystems. The use of artificial floating islands (AFI) to compensate for the deleterious effects of WLF on littoral habitats has been of increasing interest to environmental managers. Yet, the ecological efficiency of this solution is still very poorly documented. AFI are usually designed as simple vegetated floating mats. In this study, we designed an artificial Floating Littoral Zone (FLOLIZ), which mimics a natural littoral zone composed of a terrestrial section vegetated with helophytes and several underwater levels containing soil and hydrophytes. Next, we aimed to assess the effectiveness of FLOLIZ in supporting macroinvertebrate communities. Three FLOLIZs were installed in three bays of a French hydroelectric reservoir marked by high WLF. Taxonomic and functional metrics of macroinvertebrate communities in the three FLOLIZs were compared with control littoral stations over four seasons of one year. The cumulated abundance, taxonomic richness and diversity were significantly higher in the FLOLIZs than in the control littoral stations, particularly when water level rose abruptly (i.e., in spring) and during the post-drawdown season (i.e., in summer). Functional profiles of macroinvertebrate communities significantly differed between FLOLIZs and control littoral stations. More specifically, communities in littoral control stations were dominated by highly mobile and resistant taxa (e.g., Beetles, Bugs, Chironomids), while communities in the FLOLIZs were dominated by less mobile species with longer life cycles (e.g., Hydra sp., Oligochaeta). These findings show that FLOLIZs were more successfully colonized by original, diversified, and abundant macroinvertebrate communities with respect to littoral control stations. These preliminary results suggest that FLOLIZs could provide suitable, biogenic habitats for macroinvertebrates in reservoirs exhibiting high WLF. Longer term monitoring, including of other compartments than macroinvertebrates (e.g., fish), could provide additional evidence that FLOLIZs mitigate the deleterious effects of high WLF on aquatic biodiversity.

Ecological assessment of high sediment loads based on macroinvertebrate communities in the Bohemian Massif in Austria – A sensitivity analysis

Sediment dynamics and composition in streams are key factors influencing the habitat quality of aquatic organisms, consequently playing an important role in terms of river restoration. The superposition of the river-bed with fine sediments is an increasing global stressor affecting local habitat diversity and leading to changes of benthic communities. We analysed benthic macroinvertebrates in five streams of the Bohemian Massif from morphologically unaffected reference sites, and impacted sites influenced by fine sediment deposition (D = 1 mm – 10 mm) of different intensity. Siltation resulted in a gradually decline in biodiversity, abundance and biomass of macroinvertebrates linked with increasing fine sediment deposition. While for reference sites, dominated by coarse substrates, a specific community was allocated, no characteristic fauna was identified for the impacted sites. However, the results of the EU Water Framework Directive compliant Austrian national method for assessing the ecological status did not react accordingly. Solely streams highly impacted by fine sediment deposition in combination with low river-bed heterogeneity and non-natural riparian conditions indicated status shifts. Based on positive faunal responses to micro-habitats such as woody debris we recommend to support the introduction of small-scaled river restorations and anthropogenic initiated river-type specific stable structural elements (e.g. large stones) serving as refugial habitats, which can result in a significant improvement of macroinvertebrate diversity and composition.

Diversity of Macro Invertebrates and Their Habitat Characteristics in Lan-Kuu Freshwater Wetland, Myanmar

Lan-Kuu freshwater wetland of Auk SaThar in Mingin Township, Sagaing Region was investigated for its species composition, relative abundance, and diversity of aquatic macro-invertebrates from June 2020 to January 2021. This wetland has water throughout the year and is used by many local people for fishing and trapping birds. Thirty macro invertebrates’ species belonging to 28 genera, 19 families, 11 orders, 5 classes, and 3 Phyla were identified and recorded. These species belonged to the orders Hemiptera (23%), Coeleoptera and Odonata (14% each), Orthoptera, Architaenioglossa and Sorbeoconcha (10% each), Lepidoptera (7%), and Hymenoptera, Araneae, Decapoda, and Opithopora (3%). Among the collected specimens Dytiscus verticalis accounted for the highest number of individuals while the least number of individuals were Arocatus rusticus. Average relative abundance indicated 9 species as ‘uncommon’, 14 species as ‘common’ and 7 species as very common in the studied wetland. According to the Shannon index, the diversity of macro-invertebrates recorded in Lan-Kuu freshwater wetland, Myanmar, was high, (2.746-3.016), and so was the evenness (0.888-0.956).

Effect of Environmental Stressors on the Distribution and Abundance of Macroinvertebrates in Upper Awash River at Chilimo Forest, West Shewa, Ethiopia

Ethiopia is experiencing deterioration in river quality resulting in adverse effects on human health and hydrobionts. This study aimed to analyse the effects of specific environmental stressors on the distribution and abundance of macroinvertebrates in the Upper Awash River. The study was conducted from January 2018 to March 2018. Macroinvertebrates were collected from five sites using standard handheld nets. Physicochemical parameters including electrical conductivity, dissolved oxygen, total phosphorous, nitrate-nitrogen, pH, dissolved oxygen and water temperature that can affect the distribution and abundance of macroinvertebrates were assessed. A total of 14,465 individuals belonging to 33 families of insects and 5 families of the noninsect group were identified. Among all recorded taxa, Diptera was the most abundant and diversified order. Macroinvertebrates among the five sites showed variation in species evenness, richness, and Shannon Diversity Index. Values obtained from biotic indices and environmental parameters indicated the presence of organic pollution at different levels. The impacted downstream site paper mill waste (Walgata) had the relatively highest H-FBI index followed by Osole (more agricultural activities) indicating that Walgata and Osole were poorer in benthic faunal diversity than other sites. In addition, as habitat and water quality degradation increased, the number and percentage of Plecoptera, Ephemeroptera, and Trichoptera (EPT) decreased. The selected metrics will be also useful for the monitoring and assessment of the riverine systems and to access the impact of different stressors. As perturbation increased, species diversity, ETHbios index, Average Score Per Taxon, and family richness decreased, while the percentage of Chironomidae, Diptera, Dominant Taxa, and Hilsenhoff Family-Level Biotic Index increased indicating that tolerant species become abundant in degraded river bodies. Environmental protection agencies of governmental and nongovernmental organizations should make awareness for the local people so that they reduce activities that affect the river. Paper factory should also monitor its effluent from directly discharging into the Upper Awash River.

Responses of Macroinvertebrate Community Temporal Dissimilarity and Abundance to the Water Level Fluctuation Range in a Shallow Lake

Variations in the hydrological regime are among the anthropogenic pressures affecting biological assemblage structure in shallow freshwater lakes. We estimated the effects of the water level fluctuation range on the temporal dissimilarity of the macroinvertebrate community by sampling benthic macroinvertebrate assemblages monthly in 2017 and bimonthly in 2018. Then, we applied a boosted regression trees (BRT) model to quantitatively analyzing the relationship between macroinvertebrate abundance and microhabitat factors in different seasons. To distinguish differences in water level fluctuations at the sample site scale, we proposed a variable, namely, the percentage of water level fluctuation range (PWLFR). The results were as follows. (1) An increased water level fluctuation range would lead to more temporally heterogeneous macroinvertebrate communities. Temporal dissimilarity of macroinvertebrates increased linearly in response to increasing water level fluctuation range. (2) Species abundance presented seasonal characteristics, and the dominant factors affecting species abundance varied with the seasons. PWLFR was the dominant variable explaining macroinvertebrate abundance in summer. Macroinvertebrate abundance showed positive effects with increasing PWLFR. (3) The interaction between chlorophyll a and PWLFR in summer promoted an increase in macroinvertebrate abundance. These findings may provide a basis for the formulation of effective ecological water replenishment management decisions aimed at maintaining the stability of shallow lake ecosystems in arid and semi-arid regions.

Littoral macroinvertebrate communities of alpine lakes along an elevational gradient (Hohe Tauern National Park, Austria).

Alpine lakes support unique communities which may respond with great sensitivity to climate change. Thus, an understanding of the drivers of the structure of communities inhabiting alpine lakes is important to predict potential changes in the future. To this end, we sampled benthic macroinvertebrate communities and measured environmental variables (water temperature, dissolved oxygen, conductivity, pH, nitrate, turbidity, blue-green algal phycocyanin, chlorophyll-a) as well as structural parameters (habitat type, lake size, maximum depth) in 28 lakes within Hohe Tauern National Park, Austria, between altitudes of 2,000 and 2,700 m a.s.l. The most abundant macroinvertebrate taxa that we found were Chironomidae and Oligochaeta. Individuals of Coleoptera, Diptera, Hemiptera, Plecoptera, Trichoptera, Tricladida, Trombidiformes, Veneroida were found across the lakes and determined to family level. Oligochaeta were not determined further. Generalized linear modeling and permanova were used to identify the impact of measured parameters on macroinvertebrate communities. We found that where rocky habitats dominated the lake littoral, total macroinvertebrate abundance and family richness were lower while the ratio of Ephemeroptera, Plecoptera and Trichoptera (EPT) was higher. Zoo- and phytoplankton densities were measured in a subset of lakes but were not closely associated with macroinvertebrate abundance or family richness. With increasing elevation, macroinvertebrate abundances in small and medium-sized lakes increased while they decreased in large lakes, with a clear shift in community composition (based on families). Our results show that habitat parameters (lake size, habitat type) have a major influence on benthic macroinvertebrate community structure whereas elevation itself did not show any significant effects on communities. However, even habitat parameters are likely to change under climate change scenarios (e.g. via increased erosion) and this may affect alpine lake macroinvertebrates.

Long-term dynamics of the abundance of earthworms and enchytraeids (Annelida, Clitellata: Lumbricidae, Enchytraeidae) in forests of the Central Urals, Russia.

BackgroundSince the late 1980s, long-term monitoring of terrestrial ecosystems in metal-contaminated areas has been carried out in the Central Urals. As a part of these monitoring programmes, the data on soil macroinvertebrates in undisturbed areas as reference sites continues to be gathered. These data help study the local biodiversity and long-term dynamics of soil macroinvertebrate abundance in non-polluted areas.New informationThe dataset (available from the GBIF network at https://www.gbif.org/dataset/bf5bc7f6-71a3-4abd-8abc-861ee3cbf84a) includes information from a long-term monitoring programme for two taxa of Annelids, Lumbricidae and Enchytraeidae, which dwell in the topsoil of spruce-fir, birch, pine and floodplain forests in the Central Urals. The dataset includes information on the earthworm community structure (list of species, species abundance, number of egg cocoons, cocoon exuvia, juveniles and adults) and enchytraeid abundance. The dataset consists of 553 sampling events (= samples, corresponding to upper and lower layers of the soil monoliths) and 12739 occurrences (earthworms, mainly identified to species and earthworm cocoons and enchytraeids, identified to family) collected during 1990–1991, 2004, 2014–2016 and 2018–2020. In total, 3305 individuals of earthworms were collected, representing ten (out of twelve) species and all eight genera recorded for the fauna of the Central Urals. In addition, 7292 earthworm egg cocoons and cocoon exuvia and 6926 individuals of enchytraeids were accumulated. The presence-absence data on each of the ten earthworm species, egg cocoons, cocoon exuvia and enchytraeids are provided for each sampling event. All data were collected in undisturbed non-polluted areas and are used as a local reference for ecotoxicological monitoring. The dataset provides valuable information for estimating the composition and abundance of earthworm communities in different habitats over a long time and contributes to the study of soil fauna biodiversity in the Urals.

Effects of application of copper-based fungicides in cocoa plantations on the abundance and diversity of macroinvertebrates in adjacent rivers in Southwestern Nigeria

This study investigated the relationship between the levels of fungicide pollution and the abundance and diversity of macroinvertebrate fauna in three river systems: Aponmu, Oruwo, and Owena in south-western Nigeria, which are in close proximity to cocoa plantations. For each river, three sites were selected for the collection of water and sediment samples from April to July, 2018. Prior to sample collection, the physicochemical parameters (electrical conductivity, total dissolved solutes, pH, temperature, and dissolved oxygen) were determined. Also, aquatic macroinvertebrates were collected, and were identified to generic level, where possible. The levels of copper and sulphate in the samples were determined following standard procedures. The range of mean values for the physicochemical parameters were: 0.07-0.20 mS/cm, 60.00 – 154.00 ppm, 24.60 – 28.13 °C, 6.97 – 7.43, and 0.87 – 2.87 mg/L for electrical conductivity, total dissolved solutes, temperature, pH, and dissolved oxygen respectively. The range of mean values for copper and sulphate in sediment samples were 30.58 – 56.63 mg/Kg and 787.12 – 978.33 mg/Kg respectively while those for the water samples were 2.86 – 6.93 mg/L and 476.6 – 685.58 mg/L respectively. A total of nineteen (19) macroinvertebrate genera comprising Insecta (14), Gastropoda (3), Crustacea (1), and Bivalvia (1) were recorded. Taxa richness and species diversity were higher in river Owena in comparison to rivers Aponmu and Oruwo. The high abundance of the taxa: Potamididae, Gerridae, Notonectidae, Libellulidae, and Platycnemididae in the sampled rivers notwithstanding the pollution levels is an indication that these taxa are capable of thriving in polluted aquatic systems.
 Keywords: Aquatic pollution; Copper-based fungicides; Black pod disease; Macroinvertebrates; Diversityindices