Macroinvertebrate Communities Research Articles

Dissecting the urban footprint of unplanned settlements shaping macroinvertebrate communities in Wuye River, Abuja, Nigeria

Urbanization poses a significant threat to river ecosystems, causing widespread degradation of river health. This study investigates the devastating effects of urbanization on river health, with a focus on the Wuye River in Abuja, Nigeria, and dissects the urban footprint of unplanned settlements on macroinvertebrate communities. Over a six-month period (January–June 2021), we conducted a comprehensive analysis of physicochemical characteristics and macroinvertebrates at four stations, shedding light on the far-reaching consequences of unplanned urban settlements on river ecosystems. The results revealed significant deviations from optimal water quality parameters with reference to WHO guidelines. Station 3, located in unplanned urban settlement, exhibited elevated nitrate concentrations (13.0 mg/L) and heightened turbidity levels (23.6 NTU), indicating compromised water quality. Station 2, located in planned urban settlements, displayed lower nitrate values and turbidity levels. pH values ranged from 7.4 to 7.7 across all stations, suggesting minimal impact on river acidity. Canonical Correspondence Analysis (CCA) showed strong relationships between species abundance and environmental variables. Axis 2 was associated with Naucoris sp., Velia caprai, Chironomus transvalensis, and Cricotopus sp., and was influenced by dissolved oxygen, sulphate, phosphate, nitrate, and turbidity. Axis 1 was linked to seasonally influenced factors, including temperature and electrical conductivity. CCA indicated that Stations 1 and 2 had higher pH concentrations, favouring species like Melanoides tuberculatus, Appasus sp., Neritina lubricate, Bugilies sp. and Bulinus globosus. The findings highlight urgent need for effective management and conservation strategies in water treatment, urban planning and conservation policies to mitigate urbanization’s impacts on river health.

Benthic Macroinvertebrates as Bioindicators of Stream Health Within the Central African Copperbelt

Globally, stream ecosystem health in mining regions, including the Central African Copperbelt (CACB), is threatened by increased aquatic metal pollution. Stream biomonitoring and bioassessment offers an eco-friendly nature-based approach to determine the aquatic ecological conditions and inform management interventions in mining landscapes. This study conducted monthly between May 2022 and April 2023, explored the taxonomic and functional responses of macroinvertebrates as bioindicators of the ecological condition of four streams in the north-western Zambian Copperbelt of the CACB. 252 sediment samples were collected and analysed for metals. 144 macroinvertebrate samples were collected to determine their taxonomic and functional traits. ANOVA (analysis-of-variance), SIMPER (similarity-percentage), ANOSIM (analysis-of-similarities), CCA (canonical correspondence analysis) and multidimensional biotic index analyses were conducted to correlate environmental and biotic variables. Metal concentrations (mg/kg) in sediments followed the order As (5.27) < Pb (5.75) < Zn (44.6) < Ni (89.3) < Cu (187.5). From ANOVA, the macroinvertebrate community was significantly dominated by Insecta families, mostly Diptera (23.3%) and Coleoptera (16.7%). Trophically, predators significantly dominated in the order Odonata (34.7%) > Hemiptera (31.8%) > Diptera (18.9%). SIMPER depicted a strong influence of Cu, EC, velocity, sediment texture and organic matter on macroinvertebrate diversity and spatial distribution. ANOSIM indicated the highest community dissimilarity at the most impacted stream (KYABR). Habitat assessment metrics, including ZISS-1, ASPT, and EPT/Chironomidae ratio, registered a “good ecological status” with the presence of pollution-sensitive taxa (Helodidae and Perlidae), in concordance with environmental variables, confirming the suitability of macroinvertebrates as proxy bioindicators of stream health in mining landscapes. The study confirms the potential of macroinvertebrates, as potential bioindicators of stream health in mining landscapes. Their diversity and distribution is strongly influenced by Cu, EC, velocity, and sediment characteristics while habitat assessment metrics indicate a "good ecological status" despite moderate metal contamination.

Spatial Distribution and Diversity of Benthic Macrofauna in Coastal Waters of the Jabal Ali Marine Sanctuary (JAMS), Dubai

The present study aimed to characterize the benthic macroinvertebrate community of the Jabal Ali Marine Sanctuary (JAMS), the sole marine protected area in the Emirate of Dubai, during the summer and winter seasons of 2017. Limited research on the biological quality of the JAMS prompted this investigation, which involved 10 sampling stations to assess macroinvertebrate diversity and community composition in relation to abiotic factors such as sediment granulometry, trace metals, salinity, and temperature. Collected sediment samples were analyzed for macroinfauna, and their abundance was measured, revealing an average abundance of 2150 ind/m2 in summer and 2132 ind/m2 in winter without a significant difference between both seasons. Univariate indices, including the Margalef diversity index and Pielou evenness index, indicate a range of diversity values across sampling sites. Community composition was assessed through SIMPROF and Bray–Curtis similarity clustering, further elucidating the relationship between community structures and environmental gradients. The dominant macroinvertebrate species varied across seasons and stations, providing insights into seasonal variations in community dynamics. These findings contribute to the understanding of benthic community structures and biodiversity in the JAMS and serve as a baseline for future monitoring and management efforts aimed at preserving the ecological integrity of this important marine sanctuary.

Natural Disturbances and Connectivity Drive Seasonal Taxonomic and Trait Patterns of Aquatic Macroinvertebrate Communities Across Europe

ABSTRACTAimUnderstanding the joint influence of natural disturbance regime, connectivity and biogeography on the seasonal variation of community structure.LocationDrying river networks (DRN) in Europe.Time PeriodPresent.Major Taxa StudiedAquatic macroinvertebrates.MethodsWe analyse the taxonomic and trait structure of 638 macroinvertebrate communities sampled across 125 reaches with perennial and intermittent streamflow, surveyed in six DRNs across Europe, up to six times over 1 year.ResultsRichness and trait diversity of macroinvertebrate communities decreased with increasing drying frequency, but increased with spatio‐temporal connectivity in reaches with long drying events. Communities experiencing frequent drying events had higher relative abundance of taxa with a long lifecycle and drying resistance traits. Communities experiencing long drying events compensated by high spatio‐temporal connectivity, and had more taxa with high fecundity and high dispersal ability. Taxa richness peaked in summer but that pattern was more prominent when drying frequency was high. Trait diversity decreased throughout the year, showing increasing abiotic stress as the year progressed. Communities changed from communities of mobile, fecund, short‐lived taxa in spring and autumn to communities of long‐lived taxa in summer. However, when drying frequency increased, autumn communities shifted towards communities of long‐lived taxa. Macroinvertebrate community trait structure changed across Europe. It opposed communities from Mediterranean and/or upland DRNs (with more fecund and mobile taxa) to lowland DRNs (with more long‐lived taxa).Main ConclusionsFrequency and duration of drying events and spatio‐temporal connectivity drive divergent macroinvertebrate community structures, suggesting the presence of an ecological threshold that explains the variability of disturbed ecosystems across broad spatial scales. These factors also influence seasonal variations, with macroinvertebrate communities shaped by distinct trait‐filtering processes throughout the year based on drying frequency. Ultimately, spatio‐temporal connectivity plays a crucial role in sustaining species richness and trait diversity in reaches experiencing intense drying.

Multiple Diversity Measures Are Necessary to Represent Biodiversity Patterns of Lentic Communities

ABSTRACT The varying strengths of relationships between diversity measures—be they taxonomic, functional or phylogenetic—imply that biodiversity dimensionality is variable. Understanding these dimensions is essential to discerning how local communities respond to environmental changes. This study aimed to (i) evaluate the dimensionality of biodiversity in lentic systems, (ii) identify the primary measures that differentiate local communities and (iii) test the hypothesis that biodiversity dimensionality is positively correlated with environmental dimensionality. Using a large dataset encompassing phytoplankton, zooplankton and macroinvertebrate communities from lake ecosystems across the contiguous United States, I calculated Camargo's evenness index based on the eigenvalues from a principal component analysis (PCA) to assess the dimensionality of biodiversity. I also evaluated the degree to which multiple biodiversity dimensions were necessary to describe community patterns. I found that two to three sets of diversity measures were required to adequately capture the biodiversity patterns of plankton and macroinvertebrate communities, respectively. The main measures differentiating local communities were those that included the phylogenetic structure among the taxa. Taxonomic and functional richness also emerged as important variables. The anticipated positive relationship between biodiversity dimensionality and environmental dimensionality was supported for macroinvertebrate communities but not for planktonic groups. This finding suggests that environmental complexity may have distinct impacts depending on the community structure and taxonomic group considered. These study results indirectly suggest that relying on a single measure may cause studies to overlook important responses of biodiversity to environmental gradients. More importantly, in line with previous studies, I found that using only measures based on taxonomic identities falls short in differentiating lentic communities. The feasibility of using measures that require detailed information (e.g., phylogenetic structure) in real‐world contexts (e.g., bioassessment) is an issue that should be carefully evaluated in further studies.

What a load of rubbish: The impact of anthropogenic litter on urban freshwater diversity.

What a load of rubbish: The impact of anthropogenic litter on urban freshwater diversity.

Comparative Analysis of Functional Diversity and Ecosystem Health in Organic and Conventional Rice Paddies: A Trait‐Based Assessment of Benthic Macroinvertebrate Communities

ABSTRACTThis study investigated the functional diversity of benthic macroinvertebrate communities in organic paddy and conventional paddy fields using biological trait analysis and assessed ecosystem health through the Korea Wetland Benthic Macroinvertebrate Index (KWBMI). Field surveys were conducted in Yangpyeong‐gun, Korea, from June to July 2022, collecting benthic macroinvertebrate samples and environmental data. A total of 76 species, 17 orders, and 6797 individuals were identified, with biological traits analyzed among four categories: feeding habits, living types, food types, and voltinism. Community indices showed distinct differences between OP and CP. The dominance index was higher in OP, whereas CP had greater species diversity and evenness. However, functional diversity indices (FRic, FEve, FDiv, and FDis) were similar between the two fields. Despite this, OP exhibited greater taxonomic diversity within functional groups, whereas CP, despite its higher species diversity, contained functionally similar species. KWBMI scores were 84.4 for OP (Grade A: “very good”) and 75.4 for CP (Grade B: “good”), suggesting the potential benefits of organic farming for ecosystem health. Although functional diversity indices remained similar, differences in taxonomic composition and trait distributions indicate that organic farming may promote taxonomic diversity within functional groups, contributing to ecological stability.

Hydrological connectivity influences the aquatic metacommunity structure of an Arctic delta floodplain

Hydrological connectivity is a fundamental determinant of aquatic metacommunity structure. However, the potential response to altered patterns of connectivity in a changing climate remain poorly understood, particularly in regards to vulnerable systems such as Arctic deltaic lakes. Here we present the first study to examine the metacommunity structure of aquatic invertebrates in a major Arctic floodplain system (Mackenzie Delta, Northwest Territories). We sampled macroinvertebrate communities across the longitudinal span of the Delta and used three complementary analyses (variance partitioning, elements of metacommunity structure, and fourth corner analysis) to determine the relative influence of environmental versus spatial variation, metacommunity structure across dispersal modes, and the functional metacommunity structure. Environmental factors explained the most variation (23%) compared to spatial factors (2%) or environmental/spatial covariance (4%). Functional structure was primarily related to macroinvertebrate dispersal mode and lake isolation, with distributions of aerial dispersers determined mainly by environmental factors and aquatic dispersers by both dispersal limitation and environmental factors. We attribute these results to the inter-lake mixing effects of annual flooding and the lack of barriers to aerial dispersal, and discuss how a loss of aquatic invertebrate biodiversity could result from projected climate-mediated alterations to ice jam dynamics in the Delta.

Interaction of predatory macroinvertebrate communities with malaria vectors in aquatic habitats of three climatic zones in Burkina Faso

BackgroundIn aquatic larval habitats, Anopheles larvae are subject to the predatory activity and competition of macroinvertebrates. These macroinvertebrates may play a key role in the Anopheles population’s bioregulation in aquatic habitats and malaria control. There are few studies characterizing macroinvertebrate predators and other macroinvertebrates coexisting with Anopheles larvae in Burkina Faso. This study aimed at characterizing and evaluating the different interactions between anopheline mosquito larvae, predatory macroinvertebrates, and other co-habitants in aquatic habitats in the three climatic zones of Burkina Faso.MethodsA larval survey was performed in the three climatic zones of Burkina Faso (Sahelian, Soudano-Sahelian, and Soudanian zones) from September to November 2022. Mosquito larvae and other macroinvertebrates were sampled using standard dippers or bucket, preserved in Falcon tubes containing 80% ethanol, and transported to the laboratory for morphological identification. Alpha diversity analysis was used to measure macroinvertebrate diversity according to climatic zones and correlation matrix analysis was performed to determine the different interactions between Anopheles and other macroinvertebrates in breeding sites.ResultsIn the studied larval habitats, Anopheles were found with several aquatic macroinvertebrate predators and other cohabiting macroinvertebrates. The abundance and alpha diversity indices of macroinvertebrate predators and other coexisting macroinvertebrates varied significantly according to climatic zone (P = 0.01). Correlation analyses showed that in the Sahelian zone, Anopheles spp., Corixidae, and Notonectidae shared the same aquatic habitats. In the Soudano-Sahelian zone, Anopheles spp. occupied the same larval habitats with Belostomatidae, Notonectidae, and Achatinidae, and in the Soudanian zone, their presence in larval habitats was correlated with that of Beatidae.ConclusionsThis study showed a significant trophic association between Anopheles and predatory and other coexisting macroinvertebrates in larval habitats in Burkina Faso. Our study provides insights and thereby opens new avenues in terms of development of biological control against larvae of Anopheles populations in Burkina Faso.Graphical abstract

Taxonomic and functional responses of benthic macroinvertebrates to wastewater effluents in the receiving river of ecologically vulnerable karst areas in Southwest China.

Taxonomic and functional responses of benthic macroinvertebrates to wastewater effluents in the receiving river of ecologically vulnerable karst areas in Southwest China.

Impact of Sugarcane Cultivation on Benthic Macroinvertebrate Communities in Tropical Streams

Tropical streams host diverse benthic macroinvertebrates, essential for ecological processes and bioindicators of ecosystem health. However, land use changes, such as sugarcane cultivation, negatively impact stream structure and function. This study examined these effects by comparing streams in sugarcane-dominated areas with those in native vegetation. Streams with native vegetation showed 2226 individuals across 107 taxa, 39 families, and 52 genera, with Chironomidae (Chironominae, Tanypodinae), Leptoceridae, Leptophlebiidae, and Calamoceratidae being the most abundant. In contrast, sugarcane streams showed 692 individuals from 47 taxa, 24 families, and 19 genera, with Chironomidae (Chironominae, Tanypodinae), Dryopidae, and Simuliidae dominating. The first hypothesis suggested that sugarcane plantations reduce taxonomic and functional diversity. The results partially confirmed this, showing lower abundance and richness in sugarcane streams, though functionality remained unchanged. The second hypothesis proposed greater seasonal taxonomic variation in sugarcane streams due to hydrological differences. Results supported this, revealing stronger seasonal shifts, particularly during the rainy season. These findings highlight the significant impact of sugarcane cultivation on aquatic ecosystems. Continuous monitoring of macroinvertebrates in agricultural landscapes is crucial for assessing environmental impacts and guiding conservation strategies.

Pesticide Pollution Reduces the Functional Diversity of Macroinvertebrates in Urban Aquatic Ecosystems.

Urbanization accelerates innovation and economic growth but imposes significant ecological challenges, particularly to aquatic biodiversity and ecosystem functionality. Among urban stressors, pesticide-driven chemical pollution represents a critical, yet under-recognized, global threat. Quantifying the causes and consequences of pesticides on biodiversity loss and ecosystem degradation is vital for ecological risk assessment and management, offering insights to promote sustainable societal development. This study evaluated anthropogenic stressors and macroinvertebrate communities at 42 sites across two major drainages in Beijing using chemical analysis and environmental DNA (eDNA), focusing on macroinvertebrate responses to pesticide exposure in the context of multiple anthropogenic stressors. Pesticides significantly impacted the α- and β-functional diversity of macroinvertebrates, accounting for 18.46 and 14.6% of the total observed variation, respectively, underscoring the role of functional groups in pesticide risk assessment. Land use and flow quantity directly influenced pesticide levels, which in turn affected macroinvertebrate functional diversity, while basic water quality had a less pronounced effect. These results provide empirical evidence of pesticide pollution's impact on macroinvertebrate functional diversity at the watershed scale under field conditions in a highly urbanized area. The findings highlight the importance of considering multiple stressors and sensitive taxa in pesticide risk assessment and management for urban aquatic ecosystems.

Biogeographic patterns of community diversity associated with an introduced alga

Non-native foundation species may alter physical environments and provide habitat, thereby impacting recipient communities. Along the US east coast, we assessed biogeographic patterns of free-living and parasitic community diversity associated with the non-native red alga Gracilaria vermiculophylla, which is characterized by fixed (with holdfast) or free-floating thalli depending on the availability of hard substratum. In summer 2019, we surveyed 17 sites across 3 biogeographic regions. We used a random quadrat design to collect G. vermiculophylla and associated mobile macroinvertebrates per site, and we took abiotic measurements. We also haphazardly collected 100 Ilyanassa obsoleta snails per site to assess trematode diversity. In the lab, macroinvertebrates were removed from thalli and identified to lowest taxonomic level, and snails were dissected to determine trematode prevalence and diversity. Biotic and abiotic variables were analyzed for the best sets of predictors for species richness, abundance, and diversity of macroinvertebrates and trematodes across bioregions. Gracilaria vermiculophylla biomass was used as an offset in free-living analyses. Across all our US east coast sites, we detected 10,113 free-living (mobile) macroinvertebrates across 39 taxa. Three Gammaridean amphipods (Gammarus mucronatus, Ampithoe longimana, and Gammarus lawrencianus) comprised &amp;gt;50% of all detected organisms. We found biogeographic region to be a key predictor of macroinvertebrate abundance and richness. Trematode prevalence and richness were best explained by G. vermiculophylla biomass, while biogeographic region best explained diversity. As a widespread invader, our study provides evidence for associations that have formed as this foundation species has become established outside its native range. Over time, the presence and spread of G. vermiculophylla could continue to impact macroinvertebrate structure and diversity, and future work should directly compare macroinvertebrate communities with G. vermiculophylla to other foundation species along coastlines it is now common.

Urbanization results in highly dynamic, degraded benthic macroinvertebrate communities in North Carolina streams

Abstract Benthic macroinvertebrates are frequently used as bioindicators of stream health. We compared macroinvertebrate communities from 20 urban stream sites with a range of development and impervious surface cover to those from 12 highly forested stream sites to determine how urban land cover impacts in-stream communities. We also assessed the temporal change in species compositions in the urban streams from 2001 to 2021 to test whether increasing development in watersheds that are already highly urbanized led to further community degradation. Urban streams and forested streams were alternate community states, with dispersed, non-overlapping clustering in a nonmetric multidimensional scaling analysis. Urban streams were degraded by all metrics (richness, diversity, pollution tolerance) relative to the forested streams. In the urban streams, species compositions differed significantly over 20 years, with pollution-tolerant species replacing other tolerant species. However, these changes were not related to changes in land cover, and most community-level metrics (richness, diversity, pollution tolerance) remained stable. A decline in gamma diversity suggests urban macroinvertebrate communities may gradually become more homogenized. Overall, we found that land cover changes associated with urbanization, particularly increases in impervious surface cover, result in persistently degraded, dynamic macroinvertebrate communities containing a few highly tolerant species.

Contribution of Citizen Science Data on the Evaluation of Local Biodiversity of Benthic Macroinvertebrate Communities

Citizen science is increasingly utilized for environmental monitoring and educational purposes. For lotic ecosystems, this approach could be used to implement traditional methods and gain more data on local biodiversity, particularly in areas where professional monitoring is limited. This study, conducted in Italy, aimed to complement data on river macroinvertebrates collected by the Regional Environmental Protection Agency (ARPA) with additional data gained by volunteers. Our results revealed taxonomic differences between the macroinvertebrate communities of ARPA and citizen science sites. ARPA sites host 34.4% of the total biodiversity, with 22 exclusive taxa, while citizen science sites, with 6 exclusive taxa, represent 9.4% of the total gamma diversity. Compositional differences are mainly explained by taxa turnover between sites. ARPA sites, located along the main river stretches, are richer in alpha and gamma diversity, while volunteer-monitored sites, mostly in agricultural ditches, show lower richness at the local and regional scales but host some unique taxa, increasing the total biodiversity. This study supports the implementation of volunteer programs to increase the number of monitored rivers, enhancing information on macroinvertebrate diversity and distribution and generating relevant data to support decision-making and develop strategies for river conservation and ecosystem restoration at a local scale.

Spatial-temporal distributions of macroinvertebrate communities in high-mountain tropical lakes of Ecuador

Spatial-temporal distributions of macroinvertebrate communities in high-mountain tropical lakes of Ecuador

Freshwater Macroinvertebrate Community Responses to Drying Reflect Abiotic Stress, Frequency of Prior Drying and Proximity to a Perennial Reach

ABSTRACT Intermittent streams dominate global river networks and are becoming increasingly common due to global change. Understanding the mechanisms by which freshwater biota respond to flow recession, drying, and intermittence is therefore important to our ability to support biodiversity as ecosystems adapt to ongoing stressors. Responses of freshwater communities, including macroinvertebrates, are variable and likely reflect the influence of multiple drivers. We aimed to investigate how flow recession changes abiotic conditions (abiotic drying stress), and if this is affected by how frequently a site dries over the prior two years (frequency of prior drying) or the study stream. We also aimed to untangle how abiotic drying stress (hereafter referred to as drying stress), frequency of prior drying, and distance to a perennial reach interact to influence macroinvertebrate community richness and densities, turnover in taxa between locations with frequent or rare drying, drift composition, macroinvertebrate movement, and life histories. Finally, we aimed to understand whether fish that are visual predators modify macroinvertebrate behavioural responses, and if drying stress increases macroinvertebrate development rate at the cost of body length. We measured abiotic stress (channel area, discharge, temperature and dissolved oxygen) and counted moving macroinvertebrates across five streams with different fish types. We also measured abiotic stress, benthic, and drifting macroinvertebrate communities and counted moving macroinvertebrates in one stream using four sampling campaigns. Each sampling campaign occurred on a different date, and the stream dried at a location with different frequencies of prior drying and distances from a perennial reach. During each sampling campaign, data were collected at sites with different intensities of drying stress. During the sampling campaign when the channel was at its driest, macroinvertebrate drift composition and life histories (body length at each life history stage) were also collected. Temperatures increased and dissolved oxygen decreased with flow reduction, regardless of the frequency of prior drying or study stream. Mayfly development rates and macroinvertebrate movement increased as drying stress increased, but mayflies developed with shorter bodies. A fish visual predator and frequent prior drying were both associated with reduced macroinvertebrate movement. In intermittent reaches, drying stress was associated with reduced macroinvertebrate densities and richness, and taxonomic turnover. In contrast, closer to the perennial reach, there were high densities and relatively little taxonomic change associated with drying stress, possibly due to macroinvertebrate drift from communities unaffected by drying stress. Collectively, our findings suggest that drying stress, the frequency of prior drying, and distance to the nearest perennial reach interact to determine the effects of flow recession on macroinvertebrate communities. Therefore, we need to know the frequency of prior drying in a reach and the location of perennial reaches to predict outcomes of intermittency. Understanding the spatial and temporal context of the drying front is likely key to understanding and predicting community responses, particularly in the context of widespread (and growing) prevalence of intermittent streams with water resource pressures and increases in drought.

Heatwaves, elevated temperature, and insecticide-induced effects at different trophic levels of a freshwater ecosystem.

Heatwaves and increasing average temperatures associated with climate change pose severe stress on nature, including freshwater ecosystems. As these thermal stressors do not act in isolation over temporal or spatial scales, interactions with other stressors, like pesticides, may lead to unpredictable combined effects. Empirical studies investigating multiple stressor effects across different trophic levels are scarce and often lack environmental realism. Here, we performed a multiple stressor experiment using outdoor freshwater mesocosms and realistic pond assemblages including microbes, phytoplankton, macrophytes, and invertebrates. The effects of the pesticide imidacloprid at three dosings (0, 1, 10μg/L) were examined in combination with three temperature scenarios comprising natural ambient, elevated temperatures (+4°C), and repeated heatwaves (+8°C). Our results reveal fast imidacloprid dissipation for all temperature treatments with the lowest average dissipation half-lives (DT50: 6 days) in the heatwave treatment. Imidacloprid induced a series of significant effects on the macroinvertebrate community at 10μg/L across the temperature treatments. Significant declines in abundance appeared throughout the experiment for the most sensitive taxa Cloeon dipterum, Caenis sp., Chironomini, and Dero sp., whereas significant imidacloprid effects on Tanytarsini, Chironomus, and Gammarus pulex occurred only after each dosing. Only Zygoptera showed an imidacloprid-related increase in abundance, whereas significantly adverse time-cumulative effects on abundance occurred for Asellus aquaticus. The zooplankton community showed imidacloprid tolerance (10μg/L) with increasing abundances of Chydorus sphaericus, Acroperus harpae, and Ascomorpha. Heatwaves induced significantly meliorating effects on Dero sp. and adverse effects on Caenis sp., Tanytarsini, G. pulex, and A. harpae. The macroinvertebrate community demonstrated faster post-exposure recovery dynamics in the highest imidacloprid treatment when previously exposed to heatwaves and elevated temperatures compared to ambient conditions. Overall, heatwaves amplified the effects of imidacloprid on the invertebrate community, manifesting in manifold effects that adversely impacted multiple trophic levels.

Ephemeral Wetland Macroinvertebrate Communities Across Climate Regions Share Similar Functional Trait Composition Despite Near‐Total Taxa Replacement

ABSTRACT Community assembly in aquatic habitats is heavily influenced by hydrology, but understanding the influence of other habitat conditions is also critical. Most studies focus on comparisons of geographically close communities that exist under diverse hydrological regimes, but this framework limits our ability to understand how conditions other than hydrology shape ephemeral wetland communities. Here, we investigated how macroinvertebrate communities vary with local, landscape, and climate variables in ephemeral wetlands across a large geographic range with few geographic barriers. We sampled ephemeral wetlands in North Dakota, New Mexico, and Texas (USA) in 2021 and in North Dakota and New Mexico in 2022. We used an array of hydrographic, climate, landscape, and spatial variables to relate taxonomic and functional macroinvertebrate community composition and diversity to habitat conditions. Taxonomic composition was overwhelmingly different among states and between years: landscape‐scale refuge availability explained variation in taxonomic composition, but local and climate‐scale variables only explained variation within the context of other variables. Trait composition was similar between most sampling groups, but distinct trait assemblages occurred in the North Dakota 2021 communities. No predictor variable matrix explained trait composition alone, but local, climate, landscape, and spatial arrangement predicted composition when considering the overlapping influence of other variables. Taxa and trait diversity indices were associated with increased refuge habitat at landscape scale. Our results show consistent trait structure across a large geographical scale in hydrologically similar wetlands, despite almost complete taxonomic turnover between regions. Patterns in taxonomic and functional composition imply that incorporating predictor variables at multiple scales is critical in understanding ephemeral wetland community composition. Despite similar hydrological regimes and potential for connectivity via dispersal, taxa replacement is high in ephemeral wetlands across regions within a single grassland macrosystem. Taxonomic composition and overall diversity change with the context provided by a diverse suite of structuring variables. Further, we show that in most cases, ephemeral hydrology elicits a similar trait response across climate regions.

Effects of the drug carbamazepine on the structure and functioning of a freshwater aquatic ecosystem.

Effects of the drug carbamazepine on the structure and functioning of a freshwater aquatic ecosystem.