Next Article in Journal
Maximum Potential Age of Pondcypress Hydrologic Indicators Using Diameter at Breast Height
Previous Article in Journal
Influence of Optically Active Substances on Light Attenuation in a Tropical Eutrophic Urban Reservoir
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Limnological Review
Volume 25
Issue 1
10.3390/limnolrev25010008
limnolrev-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Longitudinal Distribution of Benthic Macroinvertebrates Related to River Ecological Quality

by
Māra Kostanda
1,
Gunta Spriņģe
2,
Dāvis Ozoliņš
3,
Agnija Skuja
3 and
Oskars Purmalis
2,*
1
Latvian Institute of Aquatic Ecology, Agency of Daugavpils University, Voleru st. 4, LV-1007 Riga, Latvia
2
Faculty of Science and Technology, University of Latvia, Jelgavas st. 1, LV-1004 Riga, Latvia
3
Institute of Biology, Faculty of Medicine and Life Sciences, University of Latvia, Jelgavas st. 1, LV-1004 Riga, Latvia
*
Author to whom correspondence should be addressed.
Limnol. Rev. 2025, 25(1), 8; https://doi.org/10.3390/limnolrev25010008
Submission received: 30 December 2024 / Revised: 27 February 2025 / Accepted: 11 March 2025 / Published: 14 March 2025
Browse Figures
Versions Notes

Abstract

:
Macroinvertebrates of the Venta River have been studied since the beginning of the 20th century. However, complex studies along the Venta River from the Latvian–Lithuanian border to its mouth into the Baltic Sea have been irregular and fragmentary. The aim of this study was to assess the ecological status of the Venta River and to analyze the abundance and fauna composition of macroinvertebrates along the entire length of the river in the territory of Latvia. This is the first study of its kind for the Venta River examining the specialization of macroinvertebrates in sediment substrates and their functional feeding groups. Within the framework of the study, the composition and functional importance of macroinvertebrates was assessed in 10 sampling sites together with the ecological quality of the river using several indices. The results show that the Venta River is dominated by benthic invertebrate collectors/gatherers, active filterers, grazers, and scrapers that have adapted to the particular type of sediments formed by silt, macrophytes, rocks, and pebbles. Different indices were calculated in order to assess the ecological quality of the Venta River. According to the saprobity index, the water quality corresponds to β-mesosaprobity, while ecological quality is mostly average; however, according to the multimetric indices, the quality of the Venta River varies from poor to high depending on the sampling station.

1. Introduction

A growing world population and related economic activity with climate change are among the main pressures on the water resources of the Earth [1,2]. Therefore, properly addressing water quality assessment has become a vital necessity, including ecological indicators [3,4]. Necessity dictates not only existing changes in water quality and reaching their status and quality according to sustainable development goals but also legislation on regional and local scale. Since Latvia joined the European Union (EU), the management of water bodies in the country has been implemented by the principles laid down in various EU regulations and directives. The objective of the Water Framework Directive (WFD) 2000/60/EC is to achieve good ecological status (biological and chemical) for all water bodies, therefore highlighting the importance of assessing also the ecological quality of surface waters. According to the Water Framework Directive, the ecological status of water bodies should be determined by hydro-morphological and key physicochemical quality elements with the main emphasis on the assessment of biological quality elements (BQE). The obligatory BQE to be included in the monitoring programs of EU member states for lotic environments, according to the WFD, are phytobenthos, macroinvertebrates, macrophytes, and fish [5]. Consequently, the subject of regular scientific data collection to follow the long-term trends in water quality has become topical.
Among the ecological indicators that are widely used are those which use benthic macroinvertebrates as the model organisms. This group of organisms is among those biological quality elements that are the most appropriate to characterize water quality over a longer period [6]. They possess a relatively long life cycle, limited mobility, functional diversity, and high sensitivity to environmental changes, therefore being widely used as indicators of ecological quality worldwide [7,8,9,10,11,12,13]. Wide usage to characterize different and specific aspects in various conditions such as characterization of long-term trends [14], warming effects [15], recolonization [16,17], stream restoration [18] extreme climate events [19], hydromorphological degradation [20], and pollutants [21] was supported by various species of benthic macroinvertebrates and their ecological indices. Thus, it resulted in fragmented studies and monitoring efforts with difficulties to compare geographically different areas or ambiguity about the best corresponding method in certain conditions. Therefore, existing attempts to harmonize methodologies for the application of macroinvertebrates in waterbody assessments have been made [22,23]. In Latvia, the Latvian Macroinvertebrate Index (LMI) and the Latvian Large River Macroinvertebrate Index (LRMI) have been applied since 2016 [24,25], moving from the previously used saprobity index and Multimeric Estonian method (EMMQ). Similarly, the neighboring country of Lithuania, which shares the Venta River basin, developed similar index—the Lithuanian River Macroinvertebrate Index (LRMI)—with five ecological classes [26]. Among these multimeric indices, the Danish Stream Fauna Index [27] is also used, which as individual index was considered not sensitive enough for significant number of cases among Baltic countries. The long history of using macroinvertebrates for characterizing ecological quality and the development of methodology can make it challenging to compare past results with new findings for long-term studies. Also, in our study object—the Venta River—studies of benthic macroinvertebrates have been conducted in the middle of the 20th century [28], but complex studies have been irregular and fragmentary, and newly developed indices are not directly applicable for comparison to previously detected ecological quality. Lately, a greater challenge for data comparison is ongoing climate change, and as indicated Polazzo et al. (2024) [29] and Wegscheider et al. (2023) [30], the taxonomic and functional diversity of macroinvertebrates can be altered by climate change as well as seasonal water discharge and flows. Since ongoing climate change and various anthropogenic impacts are present, it is important to not only assess ecological status of waterbodies, but also their changes due to different influencing factors. Still, some of abovementioned climate related aspects can be different among territories and in northern Europe and can be considered as relatively minor. The microhabitat preferences of freshwater macroinvertebrates can be much more influential regarding taxa richness and distribution [31,32]. Thus, this study also analyzed the substrate preference of macroinvertebrates.
The aim of this study was to assess the ecological status of the Venta River by examining the abundance and composition of macroinvertebrate fauna along its entire length in Latvia. Additionally, the study aimed to compare the results of the river’s quality assessment using the saprobity index with those derived from newly developed multimeric indices.

2. Materials and Methods

2.1. Study Site

The Venta River is the fourth longest river in Latvia, located in the western part of the country. It starts in Lithuania at the Samogitian highlands in Lake Venių, and inflows to the Baltic Sea near Ventspils city. The total length of the river is 346 km and annual runoff reaches 2.9 km3 [33]. Its length reaches 178 km in Latvia and for 3 km, it is the Latvian–Lithuanian border river [34]. In Latvia, the Venta River basin covers an area of 6600 km2 (in total 11,800 km2), a third of which is located on the northeastern slope of the Samogitian Highlands in Lithuania [34]. The average slope of the river is estimated at 0.48 m/km, while the territory of Latvia reaches 0.74 m/km [35]. The Venta River is located on Quaternary sediments of glaciogenic and glaciolimnic origin [36]. Climatic conditions in this part of Latvia are very much influenced by its closeness to the Baltic Sea, resulting in an annual average temperature of 6.5–7.0 °C, with a less pronounced winter season and, therefore, stability of snow and ice conditions. Average long-term precipitation rates are 650–850 mm and the average river flow rate in the dry season reaches 48.1 and 77.9 m3/s in the wet season [36].
Macroinvertebrates were collected in the Venta River on the Latvian side, and sites were chosen to characterize transboundary contamination across the Latvian–Lithuanian border and evaluate the impact of urbanized areas as a source of pollution (upstream and downstream of urbanized areas). Altogether, 10 sampling sites were selected to assess the ecological quality of the Venta River and to identify the composition of species and functional groups of macroinvertebrates (Figure 1).
In Latvia, the typology of rivers is based on their geographical location, bedding material, basin size, and average discharge [37]. According to the Latvian river typology and the system B typology of the Water Framework Directive [5], the sections of the Venta River can be divided into two groups: a large rhitral-type river (sites 3 and 5) and a large potamal-type river (all other sampling points). During field survey and sampling, stream velocity was also measured using AquaCMD 102-003 (Rickly Hydrological Co., Columbus, OH, USA)

2.2. Benthic Invertebrate Sampling and Sample Processing

Macroinvertebrate samples were collected in October 2013; at each sampling reach we performed the Multi-Habitat-Sampling (MHS) method with a WFD-compliant AQEM/MHS net (frame size 0.25 × 0.25 m; mesh size 0.5 mm). Collection of the samples was performed by wading if the depth was <0.8 m (downstream of Skrunda and upstream of the Šķērvelis stream mouth) or from the riverbank in the littoral zone if the depth was >0.8 m. At each sampling site, macroinvertebrate samples were collected in the littoral zone. If possible, a kick sampling technique was used; if not, sweeping was applied from the riverbank. At each sampling site, 5 sampling units (total area of 0.3125 m2) and 1 qualitative 5-min sample from different substrates (e.g., rocks, macrophytes, xylal) were collected using tweezers.
The collected material was washed through a sieve (mesh size of 500 µm) to remove the smallest sediment particles and fixed in alcohol (final solution of 70%).
Then, each sample was processed in the laboratory. The organisms were sorted and identified to the lowest possible taxonomic level under a stereomicroscope and keys were used for taxonomic identification [38,39,40,41,42,43,44,45,46,47,48]; as well as this, individuals were counted.

2.3. Data Analysis

To assess the ecological quality of the Venta River several ecological indices widely used to assess the ecological status of aquatic ecosystems were calculated for each sampling site:
  • T (Number of Taxa)—refers to the overall diversity of benthic invertebrates;
  • Number of EPT taxa (E—Ephemeroptera, P—Plecoptera, T—Trichoptera)—characterizes the number of sensitive taxonomic groups;
  • DSFI (Danish Stream Fauna Index)—refers to the level of organic pollution [49];
  • ASPT (Average Score per Taxon)—refers to the total taxon sensitivity [50];
  • H’ (Shannon–Wiener species diversity index)—characterizes the biodiversity and dominant taxonomic groups;
  • Hmax (maximum possible species diversity index)—describes what the maximum species diversity would be if, at a given sampling site, all species had the same number of individuals at a given number of species;
  • E (evenness)—characterizes the proportion of each species in relation to the total number of species at the sampling site [51].
The above-mentioned indices were calculated with Microsoft Office Excel 2021 and software ASTERICS (version 4.04) [52] using both quantitative and qualitative macroinvertebrate data.
The ecological quality assessment of the Venta was performed using the multimetric indices—LMI and LRMI—which were calculated from the values of a set of five different indices (T, Number of EPT taxa, DSFI, ASPT, and H’). These indices and the class boundaries of ecological classes were successfully intercalibrated according to the EU WFD and addressed multiple pressures, e.g., eutrophication and hydromorphological alterations [5,24,25]. The lower reaches of the Venta at the Vendzava hydroprofile and the Venta upstream of Ventspils city correspond to a very large river based on the catchment area, which is why the large river index was used for these reaches. Additionally, the Multimeric Estonian method (EMMQ) [53] was estimated (also including T, Number of EPT taxa, DSFI, ASPT and H’) which was applied in Latvia before LMI and LRMI.
The saprobity index was calculated manually using the Pantle–Buck method [54] and the Catalogue of Bioindicator Species developed for Latvian conditions [55].
The estimation of macroinvertebrate functional groups was based on the feeding mechanisms of benthic invertebrates and specialization for the substrate; calculations were carried out using the ASTERICS software (version 4.04). To evaluate the obtained functional group results, autecological information from benthic invertebrate taxonomic identifiers [38,39,40,41,42,43,44,45,46,47,48] and from the database of “Freshwaterecology” (Table 1) [56] was used [57].

3. Results

3.1. Sediment Characterization

In the Venta River, sediment substrate type variability was observed by visual assessment of the river habitat [58] throughout its length. From the Latvian border to Nīgrande (sites 1, 2), the soft substrate of fine sand, detritus, fine particulate organic matter, and coarse particulate organic matter predominates on the riverbed. Further down the river, the sediment substrate type becomes coarser and more heterogenous, and near the stream Šķērvelis mouth (site 3) it is covered with boulders, large pebbles, small pebbles, and only slightly coarse particulate organic matter and fine particulate organic material. Upstream of the town of Skrunda (site 4), only coarse and fine particulate organic matter was found. Downstream of the town of Skrunda (site 5), the riverbed substrate changes significantly and is dominated by a solid ground substrate, large pebbles, small pebbles, gravel, and coarse particulate organic matter. Between the mouth of stream Ēda and Ventspils city (sites 6–10), a soft substrate type predominates, consisting of sand, detritus, fine and coarse particulate organic matter and, in some parts, clay (Table 2).

3.2. Faunal Composition and Community Structure

Our results show that 17 different higher taxonomic groups of benthic macroinvertebrates have been identified in the Venta River. All identified taxonomic groups and individual species are listed in Table S1. Overall, the most abundant are the larvae of Diptera (especially Chironomidae, Simuliidae and Ceratopogonidae), Gastropoda (especially Bithynia tentaculata, Valvata piscinalis and Planorbidae), the larvae of Trichoptera (especially Ithytrichia lamellaris, Cheumatopsyche lepida, Oxyethira sp., Limnephilus sp.), the larvae of Ephemeroptera (especially Cloeon dipterum, Caenis horaria, Caenis luctuosa, Ephemera vulgata and Centroptilum luteolum), Bivalvia (especially Sphaeriidae and Pisidium spp.), and the larvae of Crustacea (especially Chelicocorophium curvispinum and Asellus aquaticus) (Table 3). The highest abundance of macroinvertebrates was found in rhithral sections of the Venta River.
The number of taxa at the sampling sites ranged from 38 to 80 taxonomic units, including several protected snail species in Latvia and Europe (Theodoxus fluviatilis, Ancylus fluviatilis and Gyraulus crista) [58] and also non-native species (Dreissena polymorpha, Pontogammarus robustoides, C. curvispinum) [59].
Calculated species diversity indices show a harmonized pattern and generally, none of the sampling sites displayed the dominance of any benthic invertebrate species. The average value of the evenness index in the Venta River is 0.60, having average values of 0.59 in the potamal-type river sections and 0.56 in the rhitral-type sections (Table 4).
The distribution of benthic invertebrates in the Venta River is largely related to the stream velocity and the nature of the sediments. The rapid sections of the Venta—downstream of Skrunda and upstream of the Šķērvelis stream mouth—are dominated by rheophilic benthic invertebrates that have adapted to more rapid waters, such as the larvae of blackflies Simuliidae, snails (Theodoxus fluviatilis), and mayfly larvae (Nigrobaetis niger, Baetis rhodani, Heptagenia sp.). Sections of the river where the current is slow are dominated by pelophylic and phytophilic Chironomidae and snails (Viviparus viviparus and Valvata piscinalis). The exception is the Vendzava hydro-profile, where the river is potamal type, but with a relatively heterogeneous type of substrate with increased presence of organic matter, providing such results of dominant species together with a significant number of total specimens in comparison to other potamal type river sections. There, approximately 64% of the organisms were lithophilic, with the dominant species being C. curvispinum.
The assessment of microhabitat preferences and taxonomical diversity in the Venta indicates relatively high diversity along the course of the river with one of the key features being specialization of benthic invertebrates for various substrates due to differences between rhithral and potamal sections (Figure 2). Predominantly, for rhithral sections, there is a significantly smaller proportion of pelal and an increased lithal type of microhabitat preference. The argyllal type has a significant connection to sandy substrate, in which the number of taxonomic groups is also reduced. Despite heterogeneity of Venta River substrate, its dominant habitat is still mud, macrophytes, and the presence of algae, which isn’t so expressed in sampling site no. 9, where the average depth of the river increases, resulting in a lack of heterogeneity in the substrate, therefore limiting the abundance of macrophytes.
The Venta riverbed material and the benthic macroinvertebrate specialization for the substrate also indirectly point to the food source of benthic invertebrates. The results show phytophilic organisms dominating the Venta both in the potamal and rhithral parts of the river. The dominant functional feeding groups are collectors/gatherers, active filterers, and grazers/scrapers, but the least represented are xylophages (Figure 3). For rhithral sections of river, a significant amount of macroinvertebrates are passive filterers, while in the potamal section, which is less abundant in macrophytes, the dominant role is played by active filterers. To a lesser extent, but still noticeably, there is an increase of miners in potamal river sections with fine organic and particulate matter.

3.3. Ecological Quality Assessment in the Venta River

According to the saprobity index, water quality in the Venta River corresponds to β-mesosaprobity or an average level of pollution and the values of the saprobity index vary from 1.75 to 2.26 (Table 4). The dominant taxa are Pisidium sp., Chironomidae, C. dipterum, C. horaria, E. vulgata, and Limnephilus sp., which are indicators of the β-mesosaprobic aquatic environment. Sphaeriidae, Sphaerium corneum, and B. tentaculata, as indicators of the β-α-mesosaprobic aquatic environment, and A. aquaticus, as an indicator of the α-mesosaprobic aquatic environment [60], are also abundant.
According to the ecological quality assessment method, the Venta River belongs to the type IIB—a medium-sized river with lightly colored water, low in organic matter. The calculated multimetric indices (LMI, LRMI) show a high ecological quality in the Venta River in its rhithral parts—upstream of the Šķērvelis stream mouth and downstream of Skrunda—but in the potamal parts, most of the sampling sites are at medium ecological quality, except for the downstream sampling site, where the quality is high and good according to the LRMI index (Table 5). Other calculated indices confirm limited applicability and sensitivity in comparison to LMI and LRMI to estimate the ecological quality of river. EMMQ and DSFI show good quality and only rank the 4th sampling site with moderate quality; on the contrary, the saprobity index denotes all river sections as moderate. Categorization of large potamal river sections (sampling sites 9, 10) according to the WFD lead to elevated water quality compared to sections upstream, which purely reflect the effect of the methodology, indicating potential difficulties in evaluating waterbodies on the border of typology classes.

4. Discussion

4.1. Benthic Invertebrate Species Composition and Distribution

The study of the Venta River macroinvertebrates had already started in the beginning of the 20th century with the research of the Latvian Trichoptera fauna by P. Lackschewitz [61]. In the middle of the 20th century, the Venta River mollusks were studied extensively, but the first complex and extensive studies of benthic macroinvertebrates have been carried out since 1955, resulting in various works on certain benthic invertebrate groups [24].
Studies conducted in the Venta River between 1963 and 1999 show the domination of Diptera larvae (Chironomidae), Oligochaeta, and mollusks [28], while our results indicate a decrease of Oligochaeta abundance. Instead, crustaceans and insect larvae have begun to dominate in the Venta River, suggesting possible changes in the river ecosystem as well as indicating the potential influence of adjustments of methodology. Changing the sample fixation from formaldehyde to ethanol could also have an impact on the results, as ethanol is optimal for fixing insect larvae. However, insufficient ethanol concentrations have been shown to cause the disintegration and fragmentation of oligochaete specimens, potentially leading to biased density and diversity estimates [62]. Other plausible aspects can be changes in the substrate composition and the food sources of benthic invertebrates.
The Shannon–Wiener species diversity index, maximum diversity index, and the evenness index show a relatively high species diversity in the Venta River. The Shannon-Wiener index shows lower species diversity at the Vendzava hydro-profile, where it can be described as moderate since the majority (more than 50% of the benthic invertebrates) consisted of a single non-native crustacean species, Chelicocorophium curvispinum. This species is most common in brackish waters and in the lower parts of rivers flowing into the sea; however, it has been using river systems and man-made canals for its expansion [63]. In this case, the high abundance of this species could be explained by the suitability of the habitat, depth, and sediment type. According to the observation data of the Latvian Environment, Geology and Meteorology Centre from 2006 to 2013 and the results of a study carried out in 2013, C. curvispinum is found in the lower parts of several Latvian rivers—the Venta, the Daugava, the Saka, and the Gauja [64].
According to the maximum diversity index, it is clear that less favorable conditions for macroinvertebrates are upstream of Skrunda town at sampling site 4, where the flow is relatively slow, and the most favorable conditions are downstream of Skrunda at sampling site 5, where the flow is rapid (>0.2 m/s). Thus, a link between the results of the study occurs, showing that in the rhithral parts of the Venta River, there is not only the highest taxa diversity but also the highest species diversity, according to the maximum possible species diversity index, if compared to the potamal type parts of the river. This phenomenon of higher current velocity determining higher species diversity is well recorded in European rivers [65]. However, a larger number of samples are required in order to make such conclusions regarding the Venta River since only two samples were collected at rhithral reaches and eight at potamal reaches.

4.2. Functional Groups of Benthic Macroinvertebrates

Ecological quality assessment is generally based on autecological information of species, including the specialization of benthic invertebrates for substrate or microhabits, their functional feeding groups, and their adaptation to stream velocity. Many of the macroinvertebrate species are physiologically and morphologically adapted to a variety of microbiotopes, meaning that they are associated with a specific sediment material formed by an inorganic substrate (sand, gravel, rocks) or organic substrate (macrophytes, wood, and silt) [66]. The collection of autecological information on benthic invertebrates in Europe is developed, but it is currently limited to the Ephemeroptera, Plecoptera, and Trichoptera specialization for substrate, while detailed information on other groups of benthic invertebrates is not available [57]. Some groups of benthic invertebrates have also been studied in Latvia, e.g., Trichoptera, their specialization for microhabitats, and their feeding strategies [67], but studies on other groups are incomplete. In the ecological quality assessment of our study, data from the “Database of Taxa and Autecology of Freshwater Organisms” [56] was taken into account, therefore it cannot be considered incomplete as it is based on more extensively studied groups of benthic invertebrates.
The functional specialization of macrozoobenthic organisms for feeding groups is closely related to the sediment substrate preference of benthic invertebrates. All sampling stations show the same microhabitat preference groups, which can be explained by the multi-habitat sampling approach. However, a larger proportion of pelal macroinvertebrates are found in the potamal stretches, while lithal specialists are more common in the rhithral stretches (Figure 3).
The functional feeding group classification mainly provides insight into the trophic dynamics of macroinvertebrates in aquatic ecosystems and the feeding strategies of benthic invertebrates themselves [68]. Macroinvertebrates, both in the potamal and rhithral parts of the Venta River, indicate the dominance of phytophilous benthic organisms and that their main source of food has been predominantly bacteria, algae, their cells, and fine particulate organic matter. Abundant quantities of macrophytes present in the Venta River and tributaries are described by Uzule [69], thus providing the abovementioned elements in the studied ecosystem.
The distribution of the macroinvertebrate functional groups also indirectly indicates the quality of water and the influencing factors [68,70,71,72]. For example, in Austria, after comparing rivers of different ecological quality according to macroinvertebrate functional feeding groups, it has been concluded that the proportion of grazers and scrapers is increasing in rivers under low impact. In rivers of poor ecological quality, an increased proportion of gatherers/collectors is being observed. Gatherers/collectors accounted for approximately 70% of all common functional feeding groups in rivers of poor ecological quality, whereas they accounted for only 20% in rivers of good ecological quality [70]. In the Venta River, according to the functional feeding groups, the ecological quality is characterized as moderate, as at the sampling sites, gatherers/collectors constituted the major part or approximately 40%. However, sites of good ecological quality can be found near the Vendzava hydro-profile, upstream of the Šķērvelis stream mouth, and downstream of Skrunda, where their share of all functional groups was approximately 20%.

4.3. Water Quality Assessment Based on Biotic Indices

The protection of aquatic ecosystems has been relevant since the beginning of the last century when quality standards for natural waters and their overall quality requirements were developed [5,73,74]. The ecological quality of rivers in Latvia according to macroinvertebrates has been assessed for many years by applying the Pantle–Buck saprobity index [54] and the Catalogue of Bioindicator Species developed for Latvian conditions [55]. The saprobity index is widely used in the monitoring systems of EU countries and demonstrates the spatial dynamics and seasonal fluctuations of organic pollution [75]. At the same time, our results show that the assessment of the ecological quality of the Venta River according to the saprobity index does not show significant changes among sampling sites and is not sensitive enough to indicate minor changes in ecological quality, which are much more accurately captured by the application of multimetric indices. However, the saprobity index is specifically used to assess organic pollution [54], while multimetric indices are designed to evaluate the effects of various stressors on the riverine environment to fulfill the criteria of EU WFD [5]. A similar issue was identified in Lithuania when using the DSFI [49] for more than a decade [26]. Nevertheless, the DSFI only addresses hydromorphological pressures, which led to the development of a multimetric index that was intercalibrated to align with the goals of the WFD [5]. The common features of all Biological Quality Element (BQE) assessment methods used by EU member states are that the indices are multimetric, address multiple pressures, and are divided into five class boundaries [5]. The class boundaries for the five ecological quality classes of all the indices included in Latvian LMI and LRMI and both multimetric indices are intercalibrated and aligned with those used in other EU member states [24,25]. According to WFD quality criteria, the measured water quality parameters together with sampled macroinvertebrates demonstrated poor to moderate water quality which by variability and sensitivity level between sampling points showed significant similarity with saprobity index. Meanwhile, LMI and LRMI provided a broader spectrum of estimated ecological quality. The Latvian Environment, Geology and Meteorology Centre published a report about water quality in 2021 [76], demonstrating the average ecological quality using hydrochemical parameters, indicating minor long-term water quality changes; thus, approving the use of macrointerverbates and applied multiparametric indices for characterization of ecological quality as a reliable and sensitive approach. Although, specific influencing factors should be noted, which in case of Venta River, is the episodic presence of brackish water affecting macrointerverbate communities by the dominance of C. curvispinum. Differences between the results of water parameters and the ecological quality estimated using macrointerverbates are present and were highlighted by Lemaire et al. [77], with noticeable seasonal variability and significant impact of wastewater treatment plant effluents, including pollutants, and land-use with significant source of nutrients or hydromorfological disturbances.

5. Conclusions

The results of this study showed that the diversity of the Venta River macroinvertebrate species and the distribution of their functional groups depend on their specialization to the substrate types and the river current velocity, which affects dominant substrates, e.g., silt, macrophytes, rocks, and pebbles.
The study did not identify any urban areas that could be considered a source of pollution of the Venta River. The dominant functional feeding groups in the Venta are gatherers/collectors, active filterers, and grazers/scrapers, but the least represented are xylophages. This indicates that the main food sources for benthic invertebrates are bacteria, algae, their cells, and fine particulate organic matter. According to the saprobiological quality assessment (saprobity index) of benthic invertebrates, the Venta is characterized as moderately polluted and corresponds to the β-mesosaprobity class. Still, according to the multimetric index LMI, high ecological quality has been detected upstream of the Šķērvelis stream mouth and downstream of Skrunda town, but most of the potamal-type parts are of medium ecological quality, except for the Venta at the Latvian–Lithuanian border, where it can be characterized as good. Venta at the Vendzava hydroprofile and upstream of Ventspils city corresponds to the very large river and the LRMI index shows high and good ecological status, respectively.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/limnolrev25010008/s1, Table S1: Identified macroinvertebrate species and taxons of the Venta River sampling in October 2013.

Author Contributions

Conceptualization, M.K. and G.S.; methodology, D.O.; software, O.P.; validation, A.S., G.S., and O.P.; formal analysis, M.K., G.S., and O.P.; investigation, M.K.; resources, A.S.; data curation, A.S.; writing—original draft preparation, M.K., G.S., and O.P.; writing—review and editing, M.K. and O.P.; visualization, M.K.; supervision, G.S. All authors have read and agreed to the published version of the manuscript.

Funding

This study was partly financially supported by a cross-border cooperation project between Latvia and Lithuania (2013–2014), Monitoring of Rivers and Environmental Survey of Farmers in the Lielupe and Venta River Basin Districts (LLIV-230).

Data Availability Statement

Data are contained within the article and Supplementary Materials.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Vörösmarty, C.J.; Green, P.; Salisbury, J.; Lammers, R.B. Global Water Resources: Vulnerability from Climate Change and Population Growth. Science 2000, 289, 284–288. [Google Scholar] [CrossRef] [PubMed]
  2. Alcamo, J.F.; Märker, M. Future long-term changes in global water resources driven by socio-economic and climatic changes. Hydrol. Sci. J. 2007, 52, 247–275. [Google Scholar] [CrossRef]
  3. Birk, S.; Chapman, D.; Carvalho, L.; Spears, B.M.; Andersen, H.E.; Argillier, C.; Auer, S.; Baattrup-Pedersen, A.; Banin, L.; Beklioğlu, M.; et al. Impacts of multiple stressors on freshwater biota across spatial scales and ecosystems. Nat. Ecol. Evol. 2020, 4, 1060–1068. [Google Scholar] [CrossRef] [PubMed]
  4. Muruganandam, M.; Rajamanickam, S.; Sivarethinamohan, S.; Gaddam, M.K.R.; Velusamy, P.; Gomathi, R.; Ravindiran, G.; Gurugubelli, T.R.; Muniasamy, S.K. Impact of climate change and anthropogenic activities on the aquatic ecosystem—A review. Environ. Res. 2023, 238, 117233. [Google Scholar]
  5. European Council Directive. European Commission Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 Establishing a Framework for Community Action in the Field of Water Policy. OJEC 2000, 327, 1–72. [Google Scholar]
  6. Lenat, D.R. Water quality assessment of streams using a qualitative collection method for benthic macroinvertebrates. J. N. Am. Benthol. Soc. 1988, 7, 222–233. [Google Scholar] [CrossRef]
  7. Gordon, N.D.; McMahon, T.A.; Finlayson, B.L.; Gippel, C.J.; Nathan, R.J. Stream Hydrology. An Introduction for Ecologists, 2nd ed.; John Wiley & Sons Ltd.: Chichester, UK, 2004. [Google Scholar]
  8. Li, L.; Zheng, B.; Liu, L. Biomonitoring and Bioindicators Used for River Ecosystems: Definitions, Approaches and Trends. Procedia Environ. Sci. 2010, 2, 1510–1524. [Google Scholar] [CrossRef]
  9. Rosenberg, D.M.; Resh, V.H. Freshwater Biomonitoring and Benthic Macroinvertebrates; Chapman and Hall: New York, NY, USA; London, UK, 1993. [Google Scholar]
  10. Ruzickova, J.; Benesova, L. Benthic macroinvertebrates as indicators of biological integrity in lotic feshwater ecosystems of large—Scale protected areas in the Czech Republic: Preliminary results. Silva Gabreta 1996, 1, 165–168. [Google Scholar]
  11. Hellawell, J.M. Biological Indicators of Freshwater Pollution and Environmental Management; Elsevier: London, UK, 1986. [Google Scholar]
  12. Haase, R.; Nolte, U. The invertebrate species index (ISI) for streams in southeast Queensland, Australia. Ecol. Indic. 2008, 8, 599–613. [Google Scholar] [CrossRef]
  13. Vitecek, S.; Johnson, R.K.; Poikane, S. Assessing the ecological status of European rivers and lakes using benthic invertebrate communities: A practical catalogue of metrics and methods. Water 2021, 13, 346. [Google Scholar] [CrossRef]
  14. Vaughan, I.P.; Ormerod, S.J. Large-scale, long-term trends in British river macroinvertebrates. Glob. Change Biol. 2012, 18, 2184–2194. [Google Scholar] [CrossRef]
  15. Durance, I.; Ormerod, S.J. Trends in water quality and discharge confound long-term warming effects on river macroinvertebrates. Freshw. Biol. 2009, 54, 388–405. [Google Scholar] [CrossRef]
  16. Brysiewicz, A.; Czerniejewski, P.; Sieczko, L. An assessment of maintenance works and their impact on macroinvertebrate communities and long-term recolonization to small lowland watercourses. J. Environ. Manag. 2024, 367, 121849. [Google Scholar] [CrossRef]
  17. Karádi-Kovács, K.; Szivák, I.; Bozóki, T.; Kovács, K.; Móra, A.; Padisák, J.; Selmeczy, G.B.; Schmera, D.; Boda, P. Long-term recovery dynamics determined by the degree of the disturbance—Ten years tracking of aquatic macroinvertebrate recolonisation after an industrial disaster (Red Sludge Disaster, Hungary). Sci. Total Environ. 2024, 921, 171071. [Google Scholar] [CrossRef] [PubMed]
  18. Nguyen, H.H.; Peters, K.; Kiesel, J.; Welti, E.A.R.; Gillmann, S.M.; Lorenz, A.W.; Jähnig, S.C.; Haase, P. Stream macroinvertebrate communities in restored and impacted catchments respond differently to climate, land-use, and runoff over a decade. Sci. Total Environ. 2024, 929, 172659. [Google Scholar] [CrossRef] [PubMed]
  19. Haubrock, P.J. Site characteristics determine the prevalence of extreme weather events affecting freshwater macroinvertebrate communities. Sci. Total Environ. 2024, 950, 175436. [Google Scholar] [CrossRef]
  20. de Donnová, S.; Devánová, A.; Barešová, L.; Zahrádková, S.; Bojková, J. Hydromorphological degradation modifies long-term macroinvertebrate responses to water quality and climate changes in lowland rivers. Environ. Res. 2024, 261, 119638. [Google Scholar] [CrossRef]
  21. Joachim, S.; Beaudouin, R.; Daniele, G.; Geffard, A.; Bado-Nilles, A.; Tebby, C.; Palluel, O.; Dedourge-Geffard, O.; Fieu, M.; Bonnard, M.; et al. Effects of diclofenac on sentinel species and aquatic communities in semi-natural conditions. Ecotoxicol. Environ. Saf. 2021, 211, 111812. [Google Scholar] [CrossRef]
  22. Poikane, S.; Johnson, R.K.; Sandin, L.; Schartau, A.K.; Solimini, A.G.; Urbanič, G.; Arbačiauskas, K.; Aroviita, J.; Gabriels, W.; Miler, O.; et al. Benthic macroinvertebrates in lake ecological assessment: A review of methods, intercalibration and practical recommendations. Sci. Total Environ. 2016, 543 Pt A, 123–134. [Google Scholar] [CrossRef]
  23. Simaika, J.P.; Stribling, J.; Lento, J.; Bruder, A.; Poikane, S.; Moretti, M.S.; Rivers-Moore, N.; Meissner, K.; Macadam, C.R. Towards harmonized standards for freshwater biodiversity monitoring and biological assessment using benthic macroinvertebrates. Sci. Total Environ. 2024, 918, 170360. [Google Scholar] [CrossRef]
  24. Ozoliņš, D.; Skuja, A. Fitting the New Latvian Macroinvertebrate Index (LMI) for Rivers to the Results of the Central-Baltic Geographical Intercalibration Group; Institute of Biology, University of Latvia: Salaspils, Latvia, 2016; 20p. [Google Scholar]
  25. Birk, S.; Böhmer, J.; Schöll, F.; Poikane, S. Intercalibrating the National Classifications of Ecological Status for Very Large Rivers in Europe Biological Quality Element: Benthic Invertebrates; Publications Office of the European Union: Luxembourg, 2018. [Google Scholar]
  26. Šidagytė-Copilas, E.; Arbačiauskas, K. A multimetric macroinvertebrate index for the assessment of the ecological status of Lithuanian rivers. Limnologica 2022, 97, 126010. [Google Scholar] [CrossRef]
  27. Kuntke, F.; de Jonge, N.; Hesselsøe, M.; Lund Nielsen, J. Stream water quality assessment by metabarcoding of invertebrates. Ecol. Indic. 2020, 111, 105982. [Google Scholar] [CrossRef]
  28. Parele, E. Ventas upes makrozoobentosa biocenotiskā struktūra un tās faunistiskais sastāvs no 1963. līdz 1999. gadam (Biocenotical structure and faunistic composition of macrozoobenthos in River Venta from 1963 to 1999). In Klimata Mainība un Ūdeņi. Rakstu Krājums; Plikša, I., Ed.; University of Latvia: Riga, Latvia, 2008; pp. 92–103. (In Latvian) [Google Scholar]
  29. Polazzo, F.; Domisch, S.; Flörke, M.; Rico, A. A modelling approach to assess climate change impacts on taxonomic and functional diversity of European stream macroinvertebrates: Implications for water quality monitoring. Ecol. Indic. 2024, 166, 112404. [Google Scholar] [CrossRef]
  30. Wegscheider, B.; Monk, W.A.; Lento, J.; Haralampides, K.; Ndong, M.; Linnansaari, T.; Curry, R.A. Developing environmental flow targets for benthic macroinvertebrates in large rivers using hydraulic habitat associations and taxa thresholds. Ecol. Indic. 2023, 146, 109821. [Google Scholar] [CrossRef]
  31. Vilenica, M.; Brigić, A.; Sartori, M.; Mihaljević, Z. Microhabitat selection and distribution of functional feeding groups of mayfly larvae (Ephemeroptera) in lotic karst habitats. Knowl. Manag. Aquat. Ecosyst. 2018, 419, 17. [Google Scholar] [CrossRef]
  32. Jowett, I.G.; Richardson, J.; Biggs, B.J.F.; Hickey, C.W.; Quinn, J.M. Microhabitat preferences of benthic invertebrates and the development of generalised Deleatidium spp. habitat suitability curves, applied to four New Zealand rivers. N. Z. J. Mar. Freshw. Res. 1991, 25, 187–199. [Google Scholar] [CrossRef]
  33. Klavins, M.; Rodinov, V. Long-term changes of river discharge regime in Latvia. Hydrol. Res. 2008, 39, 133–141. [Google Scholar] [CrossRef]
  34. Jēkabsone, J.; Uzule, L. Assessment of the hydromorphological quality of streams in the Venta River Basin District, Latvia. Est. J. Ecol. 2014, 63, 205–216. [Google Scholar] [CrossRef]
  35. Upes.lv. Available online: http://www.upes.lv/informacija/ventas-baseins/ (accessed on 19 November 2024).
  36. Nikodemus, O.; Kļaviņš, M. (Eds.) Latvija. Zeme, Daba, Tauta, Valsts; Latvijas Universitātes Akadēmiskais Apgāds: Rīga, Latvia, 2018. [Google Scholar]
  37. Republic of Latvia Cabinet. Regulation No. 858 “Regulations Regarding the Characterisation of the Types, Classification, Quality Criteria of Surface Water Bodies and the Procedures for Determination of Anthropogenic Loads”. 2004. Available online: https://likumi.lv/ta/en/en/id/95432 (accessed on 23 November 2023).
  38. Timm, T. A Guide to the Estonian Annelida; Naturalist’s Handbooks 1; Estonian Academy Publishers: Tallinn, Estonia, 1999. [Google Scholar]
  39. Nilsson, A. (Ed.) Aquatic Insects of North Europe. A Taxonomic Handbook; Apollo Books: Stenstrup, Denmark, 1996; Volume 1. [Google Scholar]
  40. Sloka, N. Latvijas PSR Dzīvnieku Noteicējs: Dēles (Hirudinea); P. Stučkas LVU: Rīga, Latvia, 1983. [Google Scholar]
  41. Sloka, N. Ūdensdzīvnieku Noteikšana Dabā; Zvaigzne ABC: Rīga, Latvia, 1996. [Google Scholar]
  42. Edington, J.M.; Hildrew, A.G. A Revised Key to the Caseless Caddis Larvae of the British Isles, with Notes on Their Ecology; Freshwater Biological Association: Lakeside, UK, 2005. [Google Scholar]
  43. Rudzīte, M.; Dreijers, E.; Ozoliņa-Moll, L.; Parele, E.; Pilāte, D.; Rudzītis, M.; Stalažs, A. A Guide to the Molluscs of Latvia; LU Akadēmiskais Apgāds: Rīga, Latvia, 2010. [Google Scholar]
  44. Gledhill, T.; Sutcliffe, D.W.; Williams, W.D. British Freshwater Crustacea Malacostraca: Key with Ecological Notes; Freshwater Biological Association Scientific Publication No. 52; Freshwater Biological Association: Ambleside, UK, 1993. [Google Scholar]
  45. Elliott, M.J.; Humpesh, H.U.; Macan, T.T. Larvae of the British Ephemeroptera: A Key with Ecological Notes; FBA Scientific Publications No. 49; Freshwater Biological Association: Cumbria, UK, 1988. [Google Scholar]
  46. Wallace, D.J.; Wallace, B.; Philipson, N.G. A Key to the Case—Bearing Caddis Larvae of Britain and Ireland; Scientific Publication No. 51; Freshwater Biological Association: Amblesidae, UK, 1990. [Google Scholar]
  47. Lindegaard, C. Diptera Chironomidae, Non-biting Midges. In Aquatic Insects of North Europe. A Taxonomic Handbook; Nilsson, A., Ed.; Apollo Books Stenstrup: Stenstrup, Denmark, 1997; Volume 2. [Google Scholar]
  48. Gloer, P.; Meier-Brook, C. Süsswassermollusken: Ein Bestimmungsschlüssel für die Bundesrepublik Deutschland; Deutscher Jugendbund für Naturbeobachtung: Hamburg, Germany, 1998. [Google Scholar]
  49. Skriver, J.; Friberg, N.; Kirkegaard, J. Biological assessment of running waters in Denmark: Introduction of the Danish Stream Fauna Index (DSFI). SIL Proc. 1922–2010 2000, 27, 1822–1830. [Google Scholar] [CrossRef]
  50. Armitage, P.D.; Moss, D.; Wright, J.F.; Furse, M.T. The performance of a new biological water quality score system based on macroinvertebrates over a wide range of unpolluted running-water sites. Water Res. 1983, 17, 333–347. [Google Scholar] [CrossRef]
  51. Pielou, E.C. The measurement of diversity in different types of biological collections. J. Theor. Biol. 1966, 13, 131–144. [Google Scholar] [CrossRef]
  52. AQEM Consortium. ASTERICS—Einschließlich Perlodes—Deutsches Bewertungssystem auf Grundlage des Makrozoobenthos. Softwarehandbuch. 2013. Available online: http://www.fliessgewaesserbewertung.de/downloads/ASTERICS_Softwarehandbuch_Version4.pdf (accessed on 5 April 2015).
  53. Timm, H. Towards Joint Management of the Transboundary Gauja/Koiva River Basin District: Macroinvertebrates of Estonian Streams and Lakes in 2012; Report; Estonian University of Life Sciences: Tartu, Estonia, 2012. [Google Scholar]
  54. Pantle, E.; Buck, H. Die biologische Überwachung der Gewässer und die Darstellung der Ergebnisse. Gas Wasserfach 1995, 96, 604. [Google Scholar]
  55. Cimdiņš, P.; Druvietis, I.; Liepa, R.; Parele, E.; Urtāne, L.; Urtāns, A. A Latvian catalogue of indicator species of freshwater saprobity. Proc. Latv. Acad. Sci. 1995, 1, 122–133. [Google Scholar]
  56. Freshwaterecology.info Database. Available online: https://www.freshwaterecology.info (accessed on 5 July 2024).
  57. Schmidt-Kloiber, A.; Hering, D. www.freshwaterecology.info—An online tool that unifies, standardises, and codifies more than 20,000 European freshwater organisms and their ecological preferences. Ecol. Indic. 2015, 53, 271–282. [Google Scholar] [CrossRef]
  58. Environment Agency. River Habitat Survey in Britain and Ireland: Field Survey Guidance Manual; Environment Agency: Bristol, UK, 2003; 136p. [Google Scholar]
  59. Republic of Latvia Cabinet. Regulation No. 396 “Regulations on the List of Specially Protected Species and the List of Specially Protected Species with Limited Use”. 2000. Available online: https://likumi.lv/ta/id/12821-noteikumi-par-ipasi-aizsargajamo-sugu-un-ierobezoti-izmantojamo-ipasi-aizsargajamo-sugu-sarakstu#piel1 (accessed on 10 December 2024).
  60. AquaNIS. Editorial Board. Information System on Aquatic Non-Indigenous and Cryptogenic Species. World Wide Web Electronic Publication. 2015. Version 2.36+. Available online: www.corpi.ku.lt/databases/aquanis (accessed on 5 August 2019).
  61. Lackschewitz, P. Nachtrag zu den Neuropteren und Trichopteren des Ostbaltischen Gebietes. Arch. Naturk. Est. 1929, 14, 1–64. [Google Scholar]
  62. Vivien, R.; Werner, I.; Ferrari, B.J.D. Simultaneous preservation of the DNA quality, the community composition and the density of aquatic oligochaetes for the development of genetically based biological indices. PeerJ 2018, 6, e6050. [Google Scholar] [CrossRef]
  63. CABI. Chelicorophium curvispinum (Caspian mud Shrimp). Datasheet. Invasive Species Compendium. 2017. Available online: http://www.cabi.org/isc/datasheet/108307#20077200969 (accessed on 27 June 2017).
  64. LVĢMC. Bioloģiskie Dati. Zoobentosa Dati 2006–2013. Available online: http://meteo.lv/lapas/virszemes-udens-datu-meklesana/biologiskie-dati/biologiskie-dati?id=1988&nid=950 (accessed on 5 April 2015). (In Latvian).
  65. Leszczyńska, J.; Głowacki, Ł.; Grzybkowska, M. Factors shaping species richness and biodiversity of riverine macroinvertebrate assemblages at the local and regional scale. Community Ecol. 2017, 18, 227–236. [Google Scholar] [CrossRef]
  66. Schröder, M.; Kiesel, J.; Schattmann, A.; Jähnig, S.C.; Lorenz, A.W.; Kramm, S.; Keizer-Vlek, K.; Rolauffs, P.; Graf, W.; Leitner, P.; et al. Substratum associations of benthic invertebrates in lowland and mountain streams. Ecol. Indic. 2013, 30, 178–189. [Google Scholar] [CrossRef]
  67. Skuja, A. Caddisfly (Trichoptera) Community Ecology in the Medium-Sized Rhythral Type Streams in Latvia. Ph.D. Thesis, University of Latvia, Riga, Latvia, 2011. (In Latvian). [Google Scholar]
  68. Uwadiae, R.E. Macroinvertebrates functional feeding groups as indices of biological assessment in a tropical aquatic ecosystem: Implications for ecosystem functions. N. Y. Sci. J. 2010, 3, 6–15. [Google Scholar]
  69. Uzule, L. Macrophyte vegetation assessment in streams of the Venta river basin district. Acta Biol. Univ. Daugavp. 2015, 15, 191–200. [Google Scholar]
  70. Schmidt-Kloiber, A.; Graf, W.; Lorenz, A.; Moog, O. The AQEM/STAR taxalist—a pan-European macro-invertebrate ecological database and taxa inventory. Hydrobiologia 2006, 566, 325–342. [Google Scholar]
  71. Sun, C.; Xia, L.; Zhang, M.; He, Q.; Yu, N.; Xiang, H.; Yang, H. The impacts of different seasons on macroinvertebrate community structure and functional diversity in the Jingui River China. Glob. Ecol. Conserv. 2024, 51, e02876. [Google Scholar] [CrossRef]
  72. Peng, X.; Cheng, X.; Zhu, D.; Huang, D. Application of functional feeding groups of macroinvertebrates in highly urbanized streams. AQUA—Water Infrastructure. Ecosyst. Soc. 2024, 73, 338–354. [Google Scholar] [CrossRef]
  73. Metcalfe, J.L. Biological water quality assessment of running waters based on macroinvertebrate communities: History and present status in Europe. Environ. Pollut. 1989, 60, 101–139. [Google Scholar] [CrossRef] [PubMed]
  74. Barbour, M.T.; Gerritsen, J.; Snyder, B.D.; Stribling, J.B. Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers: Periphyton, Benthic Macroinvertebrates and Fish, 2nd ed.; EPA 841-B-99-002; U.S. Environmental Protection Agency, Office of Water: Washington, DC, USA, 1999; 337p. [Google Scholar]
  75. Barinova, S. Ecological mapping in application to aquatic ecosystems bioindication: Problems and methods. Int. J. Environ. Sci. Nat. Resour. 2017, 3, 1–7. [Google Scholar] [CrossRef]
  76. LVĢMC. Pārskats par Virszemes un Pazemes Ūeņu Stāvokli 2021; gadā. LVĢMC: Rīga, Latvia, 2012. (In Latvian) [Google Scholar]
  77. Lemaire, G.G.; Rasmussen, J.J.; Höss, S.; Kramer, S.F.; Schittich, A.R.; Zhou, Y.; Köppl, C.J.; Traunspurger, W.; Bjerg, P.L.; McKnight, U.S. Land use contribution to spatiotemporal stream water and ecological quality: Implications for water resources management in peri-urban catchments. Ecol. Indic. 2022, 143, 109360. [Google Scholar] [CrossRef]
Limnolrev 25 00008 g001
Figure 1. Location of macroinvertebrate sampling sites in the Venta River (1—at border of Latvia-Lithuania; 2—upstream of Nīgrande village; 3—upstream of Šķērvelis stream mouth; 4—upstream of Skrunda town; 5—downstream of Skrunda town; 6—upstream of Ēda stream mouth; 7—upstream of Kuldīga town; 8—downstream of Kuldīga town; 9—at hydroprofile Vendzava; 10—upstream of Ventspils city).
Figure 1. Location of macroinvertebrate sampling sites in the Venta River (1—at border of Latvia-Lithuania; 2—upstream of Nīgrande village; 3—upstream of Šķērvelis stream mouth; 4—upstream of Skrunda town; 5—downstream of Skrunda town; 6—upstream of Ēda stream mouth; 7—upstream of Kuldīga town; 8—downstream of Kuldīga town; 9—at hydroprofile Vendzava; 10—upstream of Ventspils city).
Limnolrev 25 00008 g001
Limnolrev 25 00008 g002
Figure 2. Substrate preference of macroinvertebrates of the Venta River.
Figure 2. Substrate preference of macroinvertebrates of the Venta River.
Limnolrev 25 00008 g002
Limnolrev 25 00008 g003
Figure 3. Percentage distribution of functional feeding groups at sampling sites of the Venta River.
Figure 3. Percentage distribution of functional feeding groups at sampling sites of the Venta River.
Limnolrev 25 00008 g003
Table 1. Description of the macroinvertebrate microhabitat preferences and related microhabitat characteristics.
Table 1. Description of the macroinvertebrate microhabitat preferences and related microhabitat characteristics.
Type of MicrohabitatHabitat Characteristics
argyllalsilt, loam, clay (grain size < 0.063 mm)
pelalmud (grain size < 0.063 mm)
psammalsand (grain size 0.063–2 mm)
akalfine to medium-sized gravel (grain size 0.2–2 cm)
lithalcoarse gravel, stones, cobbles, boulders, bedrock (grain size > 2 cm)
phytalalgae, mosses, macrophytes
pomcoarse and fine particulate organic matter
otherother substrates
Table 2. Characteristics of the substrate type at the sampling sites.
Table 2. Characteristics of the substrate type at the sampling sites.
Type of SubstrateSampling Site
12345678910
Megalithal (>40 cm) x
Macrolithal (>20–40 cm) x x
Mesolithal (>6–20 cm) x x
Microlithal (>2–6 cm) x x
Gravelx x x
Fine sandxx xx x x
Clay and its sediments predominate x x
FPOM (fine particulate organic matter)xxxx xxxxx
CPOM (coarse particulate organic matter)xxxxxxxxxx
x: materials present in particular sampling site.
Table 3. Abundance (individuals per m2) of the Venta River benthic macroinvertebrate taxonomic groups at sampling sites in October 2013.
Table 3. Abundance (individuals per m2) of the Venta River benthic macroinvertebrate taxonomic groups at sampling sites in October 2013.
Sampling Site
12345678910Total
Bivalvia28391214688235417627522111463429156314,175
Coelenterata 12 12
Coleoptera4461641250 265513948105429465282
Crustacea612 10623858869062310,21424913,482
Diptera4037543912,59134532898268632681051765185238,094
Ephemeroptera1320141834446262576209521021723438122516,967
Gastropoda39052721186424922661226028871181706230722,984
Heteroptera130517211412412 604385563213
Hirudinea43120249125123324877637182894
Hydrachnidia4951101176240118937571429284167
Lepidoptera 12 12
Megaloptera6 12 3848 38142
Nematoda 1919
Odonata22889742428662204124325 1416
Oligochaeta883314761335815174614190288636921
Plecoptera6 1469 325 1800
Trichoptera27233052531517969159729022830427419,206
Total number of specimens (ind./m2)15,34515,95928,43210,75723,20611,46612,376552718,8808838
Table 4. Type of the river and indices characterizing species diversity in the Venta River, October 2013. Ecological quality classes: H—High quality; G—Good quality; M—Moderate quality.
Table 4. Type of the river and indices characterizing species diversity in the Venta River, October 2013. Ecological quality classes: H—High quality; G—Good quality; M—Moderate quality.
Sampling SiteType of the RiverEMMQMaximum Possible Diversity, HmaxEvenness Index, ESaprobity Index, S
1Potamal23 G4.20.61.97 M
2Potamal19 G3.80.52.07 M
3Rhithral24 H4.20.61.75 M
4Potamal16 M3.60.52.26 M
5Rhithral25 H4.40.71.80 M
6Potamal23 G4.00.72.03 M
7Potamal22 G4.10.62.04 M
8Potamal22 G3.90.81.99 M
9Potamal22 G4.10.41.86 M
10Potamaln.a.3.90.62.16 M
n.a.: not analyzed.
Table 5. Indices characterizing species diversity in the Venta River, October 2013. Ecological quality classes: H—High quality; G—Good quality; M—Moderate quality; P—Poor quality.
Table 5. Indices characterizing species diversity in the Venta River, October 2013. Ecological quality classes: H—High quality; G—Good quality; M—Moderate quality; P—Poor quality.
Sampling SiteTEPTASPTDSFIH’LMILRMI
164206.052.70.8 G
246125.542.10.5 M
370286.472.7>1 H
43895.042.00.4 P
580336.172.9>1 H
652165.452.60.6 M
760155.452.60.6 M
851115.353.10.6 M
962235.851.8 M >1 H
105075.1n.a.2.5 G 0.7 G
LMI and LRMI were calculated according to the catchment area at the sampling station. n.a.—not analyzed.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Kostanda, M.; Spriņģe, G.; Ozoliņš, D.; Skuja, A.; Purmalis, O. Longitudinal Distribution of Benthic Macroinvertebrates Related to River Ecological Quality. Limnol. Rev. 2025, 25, 8. https://doi.org/10.3390/limnolrev25010008

AMA Style

Kostanda M, Spriņģe G, Ozoliņš D, Skuja A, Purmalis O. Longitudinal Distribution of Benthic Macroinvertebrates Related to River Ecological Quality. Limnological Review. 2025; 25(1):8. https://doi.org/10.3390/limnolrev25010008

Chicago/Turabian Style

Kostanda, Māra, Gunta Spriņģe, Dāvis Ozoliņš, Agnija Skuja, and Oskars Purmalis. 2025. "Longitudinal Distribution of Benthic Macroinvertebrates Related to River Ecological Quality" Limnological Review 25, no. 1: 8. https://doi.org/10.3390/limnolrev25010008

APA Style

Kostanda, M., Spriņģe, G., Ozoliņš, D., Skuja, A., & Purmalis, O. (2025). Longitudinal Distribution of Benthic Macroinvertebrates Related to River Ecological Quality. Limnological Review, 25(1), 8. https://doi.org/10.3390/limnolrev25010008

Article Metrics

Back to TopTop