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Article

Application of the River Habitat Survey Method in the Assessment of the Human Pressure Within the Lowland River Catchment: The Mollusc Biodiversity Versus Habitat Features

by
Iga Lewin
1,*,
Przemysław Śmietana
2,
Joanna Pakulnicka
3,
Robert Stryjecki
4,
Edyta Stępień-Zawal
2,
Vladimir Pešić
5,
Aleksandra Bańkowska
6,
Agnieszka Szlauer-Łukaszewska
2,
Grzegorz Michoński
2,
Magdalena Achrem
6,
Maja Krakowiak
2,
Dominik Zawadzki
2,
Tapas Chatterjee
7 and
Andrzej Zawal
2
1
Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, 40-007 Katowice, Poland
2
Institute of Marine and Environmental Sciences, Centre of Molecular Biology and Biotechnology, University of Szczecin, 71-415 Szczecin, Poland
3
Department of Zoology, University of Warmia and Mazury in Olsztyn, Plac Łódzki 3, 10-727 Olsztyn, Poland
4
Department of Zoology and Animal Ecology, University of Life Sciences in Lublin, 20-950 Lublin, Poland
5
Department of Biology, University of Montenegro, 81000 Podgorica, Montenegro
6
Institute of Biology, University of Szczecin, 71-415 Szczecin, Poland
7
Near Hari Mandir Road, Hirapur, Dhanbad 826001, Jharkhand, India
*
Author to whom correspondence should be addressed.
Water 2024, 16(23), 3448; https://doi.org/10.3390/w16233448
Submission received: 16 October 2024 / Revised: 22 November 2024 / Accepted: 28 November 2024 / Published: 30 November 2024
(This article belongs to the Special Issue Contemporary Threats to Biodiversity in Aquatic Ecosystems)
Browse Figures
Versions Notes

Abstract

:
The objectives of our study were to analyse the degree of human pressure within the lowland river catchment in relation to the mollusc communities and to assess the usefulness of the River Habitat Survey as a field method in determining the human pressure in the mollusc biodiversity context. The River Habitat Survey (RHS), an essential method for hydromorphological studies of rivers under the requirements of the European Union Water Framework Directive, was applied. This study showed that the diversity of molluscs was impacted by several environmental factors acting simultaneously, including pH, concentration of ammonium nitrogen in water, and the habitat features depending on the degree of human pressure on the river. The result of the RHS method confirmed that the occurrence of molluscs including Unio crassus and Pseudanodonta complanata, the endangered species on a global scale, was associated with the extensive presence of several natural habitat features in the river channel. The RHS method proved to be an indispensable tool for assessing the relationships between the diversity of aquatic organisms and the degree of habitat anthropogenic modification of river environments. It seems innovative and necessary, especially in restoring the natural character of rivers.

1. Introduction

According to the Living Planet Report [1], a comprehensive analysis of trends in global biodiversity created in cooperation with experts from around the world, and the Living Planet Index, an average 69% decrease in relative abundance of globally monitored wildlife populations has been recorded since 1970. What is worse, the average abundance of global freshwater populations declined by 83%. Degradation and loss of habitats are major threats to global populations of wild animals, including freshwater habitats, i.e., fragmentation of rivers and streams and abstraction of water [1]. Almost three-quarters of the Earth’s surface has been altered, including freshwater ecosystems. To restore freshwater habitats and the natural functions of rivers, greater effort is needed. The new European Union 2030 Biodiversity Strategy is a comprehensive, systemic, and ambitious long-term plan for protecting nature and reversing the degradation of ecosystems. These include restoring at least 25,000 km of rivers free-flowing again by 2030 by removing or adjusting primarily obsolete barriers that prevent the passage of migrating fish, improving the flow of water and sediments, restoring floodplains and wetlands, and eliminating nutrient pollution [2].
Globally, the number of mollusc species in the category Critically Endangered (CR) on the IUCN Red List of Threatened Species increased from 212 to 745 in the years 1996–2024 [3]. About 30 North American freshwater mussel species and almost 65 freshwater gastropod species have become extinct in the last 100 years, and 65% of the remaining species are considered endangered, threatened, or vulnerable [4,5]. Among Mollusca, freshwater mussels (Unionoidae) represent one of the most threatened taxonomic groups in the world [5,6,7]. For example, a widespread decline of 67% in the overall abundance of freshwater mussels over the last 20 years was recorded in Portugal [8]. Among freshwater bivalve species that occurred up to 1990 in Argentina, 48% have not been recorded since 2024 [9]. Major global threats to the biodiversity of Mollusca include loss, fragmentation and degradation of habitats, pollution, overexploitation, introduction of invasive alien species (IAS), and climate change (increasing water temperature, droughts, or extreme floods). Loss of fish hosts is also important for unionid mussels [10]. The drastic decline of freshwater mollusc biodiversity can be a consequence of the accumulation and synergy of multiple human pressures on freshwater ecosystems. For example, 65 million individuals of unionid mussels (88% decline in their population) and 147 million individuals of gastropods died in the lower course of the Odra River (Central Europe) during the ecological disaster in the summer of 2022 caused by different anthropogenic factors including river regulation and secondary salinisation [11]. Freshwater Mollusca, especially mussels, play an unquestionable role in functioning river ecosystems and ecosystem services, primarily participating in biofiltration and removing particles from the water column and interstitial sediments. Freshwater mussels improve transparency and other physical properties of water quality, participate in the sequestration and transformation of substances of human origin, and remove naturally occurring substances. They filter organic matter, phytoplankton, bacteria, nutrients, heavy metals, and also pharmaceuticals, personal care products, and herbicides, improving the water quality [12]. As supporting services, the freshwater mussels participate in nutrient cycling and storage and habitat modifications [13]. Grazing Gastropoda remove and control algal biomass, including nuisance cyanobacteria and toxic algae [14].
The River Habitat Survey (RHS) method, which includes habitat quality indices, i.e., Habitat Quality Assessment (HQA) score and Habitat Modification Score (HMS), is a system for assessing the character and habitat quality of rivers based on their physical structure. The RHS method is widely used, especially in the European Union, as an important, evaluating method of the character and habitat quality of rivers according to the requirements of the EU Water Framework Directive [15]. The RHS method has been applied since 1994 in the UK and abroad [16,17,18,19,20]. The method is necessary in the assessment of hydromorphological transformations of river ecosystems, especially under human pressure and currently, is widely applied in EU countries. So far, the RHS method has not been used in the assessment of the human pressure within the lowland river catchment in the context of the mollusc biodiversity.
Therefore, in light of the important issues raised above, the following objectives of the study were formulated: (1) to analyse a degree of human pressure within the lowland river catchment in relation to the mollusc communities; (2) to assess the mollusc biodiversity in relation to the most predictive environmental factors, including the habitat features; and (3) to assess whether field method River Habitat Survey is useful in determining the human pressure within the lowland river in the mollusc biodiversity context.

2. Materials and Methods

2.1. Study Area

The research was carried out in the Krąpiel River, a medium-sized lowland river with a total length of 70 km and a catchment area of 640.2 km2 (the West Pomeranian Lakeland, northwestern part of Poland) (Figure 1). The valley of the upper course of the Krąpiel River is included in the Special Protected Area “Ostoja Ińska” (PLB320008), which was established under the Birds Directive [21] and Polish legislation. The valley of the lower course of the Krąpiel River is included in the Natura 2000, the European Network Programme of protected sites “Dolina Krąpieli” (PLH320005) as a Special Area of Conservation (SAC) that combines natural habitats of the highest value and rare or endangered species in the European Community (Figure 1).

2.2. Field and Laboratory Methods

The research was carried out from April to October 2011 in the Krąpiel River. Six sampling sections K1–K6 were established along the river course for assessments of the hydromorphological structure of the river and the collection of environmental data. Within each of the sampling sections K1–K6, 26 sampling sites were selected to represent a wide range of environmental conditions and habitats, including the riffles (R) and pools (P) for collecting samples of Mollusca, samples of the water, and bottom sediments. The samples were collected in May, July, September, and November 2011. In total, 104 samples were collected.
Samples of Mollusca were collected according to quantitative methods from each of the sampling sites within six sampling sections located along the course of the Krąpiel River. A metal square frame was used to mark out a 0.5 m2 sampling area in the bottom sediments, and then the samples of molluscs were taken using a hand dredge with a 500 µm mesh size. The collected materials were transported to the laboratory in plastic containers. The samples of molluscs were washed using a 0.5 mm mesh sieve and then preserved in 80% ethanol. Molluscs were identified to the species level based on their morphological and anatomical features according to Piechocki [22], Piechocki and Dyduch-Falniowska [23], Glöer and Meier-Brook [24], and Glöer [25]. Empty shells were not taken into account. Species nomenclature was updated according to Piechocki and Wawrzyniak-Wydrowska [26].
Samples of water and bottom sediments were collected immediately before mollusc sampling from each sampling site. Insolation (%) was measured in the field using a CEM DT-1309 light meter (CEM, New Delhi, India). The physical and chemical parameters of the water, i.e., temperature, pH, conductivity, and the concentration of dissolved oxygen, were measured in the field using an Elmetron CX-401 multiparametric sampling probe (Elmetron, Zabrze, Poland). Water flow velocity was measured using a SonTek acoustic FlowTracker flowmeter (SonTek, Washington, DC, USA). Ammonium nitrogen, nitrates, phosphates, hardness, and iron were measured using a Slandi LF205 photometer (Slandi, Michałowice, Poland) in laboratory conditions. Biochemical Oxygen Demand (BOD5) was analysed with Winkler’s method. Turbidity was analysed according to the standard methods [27]. Three measurements were performed every time.
Macrophytes cover of sampling sites was assessed using a scale from 0 to 5 (0 stands for the absence and 5 stands for the total overgrowth by macrophytes) by the Braun–Blanquet methods [28]. The proportion of mineral sediment (%), proportion of organic sediment (%), mean sediment grain size (M, mm), and sediment sorting (W) were analysed according to [29].
The hydromorphological assessment of the Krąpiel River was carried out according to the River Habitat Survey (RHS) method as adapted to Polish conditions [18,30,31,32]. The River Habitat Survey (RHS) is a method designed to characterise and assess the physical habitat structure of freshwater streams and rivers. Currently, the RHS method is applied for hydromorphological studies of rivers and streams following the requirements of the EU Water Framework Directive [15] in European countries [33,34]. The field surveys of the RHS were made at 10 equally spaced spot-checks, which are designed to record predominant channel, bank, and river corridor features at 10 locations spaced evenly along the river in each of six sampling sections K1–K6 (Figure 1). The fieldwork of the RHS method included the quality assessment of the habitat attributes based on the point scale and spot-check-key [30,31], e.g., the assessment of the physical attributes of the channel features and the predominant substrate, marginal and bank features, predominant flow-type, and channel vegetation types (Supplementary Materials Table S1). The values of four indices were calculated based on the field results of the RHS method [32,35]:
  • The Habitat Quality Assessment (HQA)
  • The Habitat Modification Score (HMS)
  • The River Habitat Quality (RHQ)
  • The River Habitat Modification (RHM)

2.3. Statistical Analyses

The biodiversity of the mollusc communities was analysed using the Shannon–Wiener index H′ according to McCune and Grace [36]:
H′ = −Ʃ (Pi) (log2 Pi)
where
Pi = Ni/N-the proportion of individuals belonging to species i
The density of Mollusca is estimated as the number of individuals per square metre. Canonical ordination analyses for relating the species composition of Mollusca to the environmental variables including habitat features and indices concerning the RHS method were carried out using CANOCO for Windows version 4.5 [37]. Preliminary Detrended Correspondence Analysis (DCA) on the biological data revealed that the gradient length did not exceed 3 SD (the standard deviation), indicating that the biological data exhibited linear responses to the underlying environmental variables, which justified the use of linear multivariate methods. Therefore, a linear direct ordination redundancy analysis RDA with a forward selection was used to reduce the large set of environmental variables. The statistical significance of the relationship between the biological data and the environmental variables was evaluated using the Monte Carlo permutation test (499 permutations). The habitat attributes and the hydromorphological indices that were selected for the redundancy analysis RDA are shown in Table S1 (Supplementary Materials).
The significance of the differences in the median values of the physical and chemical parameters of the water, type of substratum (mineral, organic), insolation, macrophytes cover, number of mollusc species, and density between sampling sections of the Krąpiel River was calculated using the Kruskal–Wallis one-way ANOVA and the multiple comparison post hoc tests. The values of the biological and environmental data did not reveal a normal distribution according to the Lilliefors test of normality; therefore, non-parametric tests have been used. The statistical analyses were performed using Statistica version 13.3.

3. Results

3.1. The Environmental Factors

The values of the conductivity from 142 µS cm−1 to 345 µS cm−1 increased along with the course of the river (Table 1). Wide range of BOD5 (Biochemical Oxygen Demand) was recorded for the sampling section K1, and wide ranges of pH were recorded for sampling sections K1, K3, K4, and K5. The relatively high maximum value of ammonium nitrogen concentration up to 2.48 mg dm−3 was recorded for the sampling section K2.
The minimum values for the concentration of dissolved oxygen (1.6 mg dm−3) and pH (5.98) occurred in the sampling section K2 (Table 1). The Kruskal–Wallis one-way ANOVA and multiple comparison post hoc tests showed statistically significant differences in the values of most environmental factors between river sampling sections except for temperature, turbidity, velocity, organic, and mineral fractions in bottom sediments (Table 1). The values of the HQA index ranged from 22 (sampling section K2) to 56–57 (sampling sections K6-K5), and the values of the HMS ranged from 0 (sampling sections K3 and K5) to 34 (sampling section K2) (Supplementary Materials Table S1). The value of the HMS was 15 for the sampling section K6.

3.2. The Structure of Mollusc Communities

A total of 32 taxa of Mollusca were recorded in the six sampling sections of the Krąpiel River: 18 gastropod and 14 bivalve taxa (Table 2). Theodoxus fluviatilis (Linnaeus, 1758), Bithynia tentaculata (Linnaeus, 1758), and Sphaerium corneum (Linnaeus, 1758) constituted a large percentage share in mollusc communities both in the riffles and pools in most of the river-sampling sections (Table 2). The rare gastropod species Bithynia leachii (Sheppard, 1823) was recorded only in sampling sections K1 (riffle) and K2 (riffle and pool). Invasive alien species (IAS), i.e., Potamopyrgus antipodarum (Gray, 1843) occurred in pool and riffle in sections K3 and K5. A total of nine fingernail clam species (Sphaeriidae) and three unionid species (Unionidae), i.e., Unio crassus Philipsson, 1788, Pseudanodonta complanata (Rossmässler, 1835), and Anodonta anatina (Linnaeus, 1758) were found in the Krąpiel River (Table 2). Among them, Unio crassus, one of the species of European Community interest whose conservation requires the designation of special conservation areas within the Habitats Directive Natura 2000 [34], was recorded in the riffle of sampling section K4. The values of the Shannon–Wiener index H′ calculated for the mollusc communities ranged from 1.24 (riffle, sampling section K2) to 2.86 (riffle, sampling section K4) (Table 2). The number of mollusc taxa ranged from one to nine, and the density ranged from 1 to 162 individuals m−2. The Kruskal–Wallis one-way ANOVA and multiple comparison post hoc tests revealed statistically significant differences in the median number of mollusc taxa and density between the river-sampling sections (Figure 2 and Figure 3).
A total of 32 taxa of Mollusca were recorded in the six sampling sections of the Krąpiel River: 18 gastropod and 14 bivalve taxa (Table 2). Theodoxus fluviatilis (Linnaeus, 1758), Bithynia tentaculata (Linnaeus, 1758), and Sphaerium corneum (Linnaeus, 1758) constituted a large percentage share in mollusc communities both in the riffles and pools in most of the river-sampling sections (Table 2). The rare gastropod species Bithynia leachii (Sheppard, 1823) was recorded only in sampling sections K1 (riffle) and K2 (riffle and pool). Invasive alien species (IAS), i.e., Potamopyrgus antipodarum (Gray, 1843) occurred in pool and riffle in sections K3 and K5. A total of nine fingernail clam species (Sphaeriidae) and three unionid species (Unionidae), i.e., Unio crassus Philipsson, 1788, Pseudanodonta complanata (Rossmässler, 1835), and Anodonta anatina (Linnaeus, 1758) were found in the Krąpiel River (Table 2). Among them, Unio crassus, one of the species of European Community interest whose conservation requires the designation of special conservation areas within the Habitats Directive Natura 2000 [34], was recorded in the riffle of sampling section K4. The values of the Shannon–Wiener index H′ calculated for the mollusc communities ranged from 1.24 (riffle, sampling section K2) to 2.86 (riffle, sampling section K4) (Table 2). The number of mollusc taxa ranged from one to nine, and the density ranged from 1 to 162 individuals m−2. The Kruskal–Wallis one-way ANOVA and multiple comparison post hoc tests revealed statistically significant differences in the median number of mollusc taxa and density between the river-sampling sections (Figure 2 and Figure 3).

3.3. The Mollusc Communities Versus Habitat Features

A redundancy analysis (RDA) showed that among the physical and chemical parameters of the water, pH and the concentration of ammonium nitrogen were the parameters most associated (statistically significant) with the distribution of mollusc species. Pisidium ponderosum (Stelfox, 1918), A. anatina and typical rheophilous species, i.e., U. crassus, P. complanata, Pisidum amnicum (O.F. Müller, 1774), and Pisidium supinum A. Schmidt, 1851 were positively influenced by higher pH (Figure 4). The insolation and natural, physical attributes of the river concerning the RHS method, i.e., eroding cliff (EB) and gravel Zr(S) as predominant channel substrate, also exerted a significant effect on the distribution of the mollusc species (Figure 5 and Figure 6). Figure 7 shows the relationships among the values of the hydromorphological indices based on the RHS method and the distribution of mollusc species. Distribution of some molluscs, including T. fluviatilis, Anisus lecucostoma (Millet, 1813), Planorbis carinatus O.F. Müller, 1774, P. amnicum, Pisidium personatum Malm, 1855, P. complanata and U. crassus, is positively correlated with the extensive presence of a number of natural river features reflected by the HQA and RHQ values (correlation with higher values of the HQA index). In contrast, the distribution of Planorbarius corneus (Linnaeus, 1758), B. tentaculata, Planorbis planorbis (Linnaeus, 1758), Viviparus contectus (Millet, 1813), or S. corneum is positively correlated with anthropogenic modification of the river habitat and adjacent land use reflected by the HMS values (correlation with higher values of the HMS index) (Figure 7).

4. Discussion

4.1. The Mollusc Communities: Rare and Threatened Species

Our results showed that 32 mollusc taxa, including fingernail clams (10 taxa) and unionid mussels (four taxa), occurred in different sections of the Krąpiel River depending on the various habitat features and the human pressure. Among them, unionid species, which were recorded in sections K4 and K5, i.e., P. complanata and U. crassus, are included in the IUCN Red List of Threatened Species as Endangered (EN) on a global scale, and A. anatina is assessed as Least Concern (LC) [38,39]. Pseudanodonta complanata, a rheophilous species sensitive to environmental disturbance and nutrient enrichment with a life span ranging from 8 to 32 years, is associated with lotic habitats and prefers silty-sandy substrates [26]. The main threats for P. complanata include habitat degradation and loss, improper management of rivers, water pollution, siltation, channelisation, and water abstraction [39]. Unio crassus, which was recorded in the Krąpiel River, is a species of Community interest listed in the Habitat Directive [40] of the EU under Annex II and Annex IV. His conservation requires the designation of special conservation areas within the Habitats Directive Natura 2000. The main driving factors influencing the occurrence of U. crassus include degradation and habitat loss, water pollution, regulation of riverbeds, and the lack of primary or appropriate host fishes for unionid species. Unio crassus is vulnerable to changes in water chemistry, especially to relatively high nitrate and phosphate concentrations, elevated heavy metals concentrations, to the species composition of the surrounding ichthyofauna and the degradation of natural river ecosystems [41,42,43,44]. Declines in host fish species due to habitat degradation reduced recruitment success. Similarly to unionid mussels, fingernail clam species (Sphaeriidae), which play a crucial role in the functioning of freshwater ecosystems, are often overlooked and underrated. According to Halabowski et al. [45], their occurrence is threatened by different human pressures. Therefore, effective management strategies including the protection of the habitats, and reducing water pollution and climate change effects, should be implemented. Among gastropods recorded in the upper course of the Krąpiel River, B. leachii, a rare species typical for periodic water bodies and resistant to desiccation, is classified as Critically Endangered (CR) and Near Threatened (NT), and P. carinatus as NT in some European countries [46,47].

4.2. The Mollusc Communities Versus Physical and Chemical Parameters of the Water

The decline of species richness of freshwater organisms with habitat loss is a non-linear process [48]. This study showed that the diversity of molluscs in the lowland river is influenced by several environmental factors acting simultaneously. Both the physical and chemical parameters of the water and the habitat features of the river depending on the degree of human pressure on the aquatic environment are associated with the mollusc diversity. Freshwater molluscs are bioindicators of water quality in rivers because they are sensitive to biodegradable pollution, acidification, concentrations of nutrients, and alkalinity levels. In addition, the Unionidae are the first molluscs to be eliminated by pollution [49].
Ammonium nitrogen and pH exerted a significant effect on the distribution of the mollusc species in the Krąpiel River (Figure 4). Mollusc species were associated with higher values of pH. Molluscs are more sensitive to low pH than fish, and their disappearance is an important warning signal in the case of acidification of freshwater ecosystems. Environmental calcium uptake by freshwater molluscs, which is necessary for the development of embryos and the biomineralisation of shells, can be impaired at low pH [50]. At low pH values, e.g., at pH 4.0, freshwater molluscs experience severe acidosis and lost haemolymph sodium ions and intracellular potassium ions, irrespective of concentration of environmental calcium. With the increase of pH up to 5.0, ionic and acid/base disturbances decrease with increasing environmental calcium, indicating the beneficial effects of calcium at less toxic pH levels [51]. Thus, the positive correlation between pH and the distribution of Mollusca in the Krąpiel River can be explained by their physiological makeup. Relatively harsh environmental conditions, i.e., low concentration of dissolved oxygen, relatively high concentrations of ammonium nitrogen, and low pH, were recorded at sampling section K2 in the Krąpiel River. The RDA results showed that some mollusc species, including S. corneum, P. corneus, P. planorbis, and B. tentaculata, were associated with sampling sites with higher ammonium nitrogen concentrations in the water. According to Lewin [43], gastropod species, i.e., B. tentaculata, P. corneus, P. planorbis, and fingernail clam S. corneum, are more tolerated to elevated nutrient concentration, i.e., nitrites, nitrates, and phosphates, than other mollusc species, but up to a certain limit. For example, S. corneum is the most tolerant species and was recorded at river sites with the upper limit of nitrates (up to 136.00 mg NO3− dm−3), nitrites (up to 2.64 mg NO2− dm−3), and phosphates (up to 8.98 mg PO43– dm−3) [43]. Especially, planorbid species, i.e., P. corneus and P. planorbis, are able to survive harsh environmental conditions including dissolved oxygen deficits. Both species retract deep into shells and form mucous membranes (epiphragm) between the aperture and the body, which prevent them from unfavourable environmental changes. Due to their adaptive biology and ecology, they can survive oxygen deficits in the water, high water temperatures, changes in pH and salinity, or drying of aquatic environments. In contrast, the unionid species, sensitive to nutrient enrichments, are the first molluscs to be eliminated by water pollution [49]. Unionid species are recorded in riverine habitats with the upper limit of ammonium nitrogen of 0.8 mg dm−3 or a median phosphate concentration of about 1 mg dm−3 [43,52]. For example, successful growth of juveniles and recruitment of U. crassus is recorded in non-polluted rivers with a low concentration of ammonium nitrogen up to 0.32, nitrites, nitrates, or phosphates up to 0.35 mg PO43– dm−3) [41,42,53].

4.3. The Mollusc Communities Versus Habitat Features

A significant relationship among the distribution of mollusc species and some habitat features of the Krąpiel River, i.e., eroding cliff and gravel sediments, was also recorded. Fingernail clams, i.e., S. corneum, Pisidium milium Held, 1836, Pisidium subtruncatum Malm, 1855, and Pisidium nitidum Jenyns, 1832, were associated with gravel sediments. Our results confirm earlier research of Meier-Brook [54] that fingernail clam species show preferences in relation to the substratum. Certain species are associated with coarser substrate (above 8 mm) because large-pored interstitial spaces enable them to take up oxygen-rich water but also prevent them from sinking while crawling on the surface of the substratum. In comparison, according to the RDA analysis, the unionid species were associated with vegetated mid-channel bars, i.e., elevated regions of sand and gravel that have been deposited by the flow in the Krąpiel River. Unionid mussels, for example, P. complanata, prefers silty and sandy-silty sediments, and U. crassus prefers sandy and gravelly substratum [26]. According to Strayer [55], habitat features are the most important factor limiting the occurrence of freshwater mussels.
The application of the RHS field method enables assessing the human pressure within the lowland river catchment in relation to the mollusc diversity based on the two numerical metrics, i.e., the Habitat Quality Assessment (HQA) and the Habitat Modification Score (HMS). Both indices were the most important (statistically significant) in explaining the distribution pattern of Mollusca in the Krąpiel River. High values of the HQA score reflect a large number of the natural characteristics of rivers and the adjacent land use. More sensitive mollusc taxa, including unionid mussels and some fingernail clams, were associated with the extensive presence of a number of natural river features reflected by the higher values of the HQA. The HQA, which is the result of a variety of measures of habitat natural features, includes, e.g., channel substrates and deposition features, in-channel and bankside structure of vegetation, aquatic fauna, and the extent of near natural land use adjacent to the river. The HQA values ranged from 22 to 57 for the Krąpiel River. For comparison, the values of the HQA index ranged from 10 to 88 for most European rivers [48,56,57,58]. For Asian rivers, the HQA values ranged from 25–60 [19], indicating fewer natural features in comparison with European rivers. The higher the HQA value, the greater the degree of naturalness of the habitat features of the rivers and the lower the degree of human pressure [59,60,61]. In contrast, a high value of the HMS index reflects a high degree of modification of the habitat features and high human pressure. According to Lewin et al. [59], the values of the HMS index ranged even up to 140 for human-impacted streams (the Kluszkowianka, Poland), in which the riverbanks and riverbed have been strengthened with concrete. Some authors assumed that the upper limit of the values of the indices based on the RHS method for unimpacted streams under reference conditions amount to HMS < 8 and HQA > 47, respectively [59]. Our research showed a positive correlation among common and most tolerant mollusc species, including S. corneum, P. corneus, or P. planorbis, and some modifications of river habitats reflected by the values of the HMS index. However, a maximum HMS value ranged up to 34 for the sampling section K2 of the Krąpiel River.

5. Conclusions

The Krąpiel River supports rare and globally endangered mollusc species, including bivalve mussels. Among them, the unionid mussel Unio crassus, one of the species of EU interest, was recorded. However, Unio crassus and Pseudanodonta complanata, the species included in the IUCN Red List of Threatened Species as Endangered (EN) on a global scale, occurred outside the border (sampling section K4) of the Special Area of Conservation (SAC) PLH320005, which include the lower course of the river only. Therefore, the boundaries of the protected site PLH60023 should be extended to conserve endangered mussel species and the highest mollusc biodiversity measured by the maximum value of the Shannon–Wiener index H′. In contrast, the New Zealand mud snail Potamopyrgus antipodarum, an invasive alien species, was recorded in two sampling sections of the Krąpiel River (K3 and K5) located in both protected areas. Since Potamopyrgus antipodarum in higher densities negatively affects native molluscs and can be spread by waterfowl, it is worth considering this aspect in further environmental studies. The ammonium nitrogen, pH, and the habitat features of the river, depending on the degree of human pressure, exerted a significant effect on the distribution of the mollusc species. Mollusc species, including unionid bivalves, were associated with the number of natural habitat features in the river channel and the adjacent area (a significant correlation with higher values of the HQA index). Based on the RHS method, our results confirm more natural habitat features and adjacent land use, and less human pressure on the aquatic environment, in the lower course of the Krąpiel River at the Special Area of Conservation (SAC) PLH320005 “Dolina Krąpieli” (sampling sections K5-K6). In contrast, higher values of the HMS index, reflecting the greater degree of human pressure on river habitats, were recorded for the upper course of the Krąpiel River on the Special Protection Area PLB320008 “Ostoja Ińska” (sampling sections K1–K2). In our research, the application of the RHS method was indispensable in the assessment of the relationship between the distribution pattern of Mollusca and the habitat features. The obtained numerical values of the indices based on the RHS method enabled the assessment of the degree of human pressure on the aquatic environment. Therefore, we would like to recommend the RHS method as an essential tool for the assessment of the significant relationships between the diversity of aquatic organisms and the degree of habitat anthropogenic modification of river environments. This method seems to be innovative and necessary, especially in the sustainable management of the environment and water resources, in projects of the impact of investments on the environment, conservation of the environment and river habitats, and restoring the natural character of rivers, not only in the context of implementation the new European Union 2030 Biodiversity Strategy.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/w16233448/s1, Table S1: The list of habitat attributes based on the point scale and spot-check-key and the values of the hydromorphological indices obtained by the application of the River Habitat Survey (RHS) method in the Krąpiel River (Poland) (*the habitat attributes and hydromorphological indices selected to the redundancy analysis (RDA).

Author Contributions

Conceptualization, I.L., P.Ś. and A.Z.; Methodology, I.L., A.Z., J.P. and V.P.; Formal analysis, I.L., P.Ś., J.P., R.S., E.S-Z., V.P., A.B., A.S.-Ł., G.M., M.A., M.K., D.Z., T.C. and A.Z.; Investigation, I.L., P.Ś., J.P., R.S., E.S.-Z., A.B., A.S.-Ł., G.M., M.A. and A.Z.; Data curation, I.L. and J.P.; Writing—original draft preparation, I.L., P.Ś., J.P., R.S., V.P., A.B. and A.S.-Ł.; Writing—review and editing, I.L., P.Ś., J.P., R.S., E.S.-Z., V.P., A.B., A.S.-Ł., G.M., M.A., M.K., D.Z., T.C. and A.Z.; Visualization, I.L., P.Ś. and J.P.; Supervision, I.L.; Project administration, A.Z.; Funding acquisition, A.Z. All authors have read and agreed to the published version of the manuscript.

Funding

The project was supported by the Minister of Science under the “Regional Excellence Initiative” Program for 2024–2027 (RID/SP/0045/2024/01).

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

The authors are grateful to Andrzej Piechocki for the identification of species, to the Editor-in-Chief, to the Assistant Editor, and to the anonymous Reviewers for their valuable suggestions and comments, which significantly improved the quality of this manuscript.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. WWF. Living Planet Report 2022—Building a Nature-Positive Society; Almond, R.E.A., Grooten, M., Juffe Bignoli, D., Petersen, T., Eds.; WWF: Gland, Switzerland, 2022. [Google Scholar]
  2. Biodiversity Strategy 2030 Barrier Removal for River Restoration; European Commission, Publications Office of the European Union: Luxembourg, 2021.
  3. The IUCN Red List of Threatened Species, Version 2024-1. Available online: https://www.iucnredlist.org/ (accessed on 12 September 2024).
  4. Haag, W.R.; Williams, J.D. Biodiversity on the brink: An assessment of conservation strategies for North American freshwater mussels. Hydrobiologia 2014, 735, 45–60. [Google Scholar] [CrossRef]
  5. Hopper, G.W.; Bucholz, J.R.; DuBose, T.P.; Fogelman, K.J.; Keogh, S.M.; Kubala, M.E.; Lodato, M.B.; Nichols, D.H.; Sánchez González, I.; Pfeiffer, J.M.; et al. A trait dataset for freshwater mussels of the United States of America. Sci. Data 2023, 10, 745. [Google Scholar] [CrossRef] [PubMed]
  6. Ollard, I.; Aldridge, D.C. Declines in freshwater mussel density, size and productivity in the River Thames over the past half century. J. Anim. Ecol. 2023, 92, 112–123. [Google Scholar] [CrossRef] [PubMed]
  7. Aldridge, D.C.; Ollard, I.S.; Bespalaya, Y.V.; Bolotov, I.N.; Douda, K.; Geist, J.; Haag, W.R.; Klunzinger, M.W.; Lopes-Lima, M.; Mlambo, M.C.; et al. Freshwater mussel conservation: A global horizon scan of emerging threats and opportunities. Global Chang. Biol. 2023, 29, 575–589. [Google Scholar] [CrossRef] [PubMed]
  8. Lopes-Lima, M.; Reis, J.; Alvarez, M.G.; Anastácio, P.M.; Banha, F.; Beja, P.; Castro, P.; Gama, M.; Gil, M.G.; Gomes-dos-Santos, A.; et al. The silent extinction of freshwater mussels in Portugal. Biol. Conserv. 2023, 285, 110244. [Google Scholar] [CrossRef]
  9. Torres, S.H.; de Lucía, M.; Gutiérrez Gregoric, D.E.; Darrigran, G. Freshwater mussel conservation in southern South America: Update on distribution range and current threats. Aquat. Sci. 2024, 86, 38. [Google Scholar] [CrossRef]
  10. Lopes-Lima, M.; Sousa, R.; Geist, J.; Aldridge, D.C.; Araujo, R.; Bergengren, J.; Bespalaya, Y.; Bódis, E.; Burlakova, L.; Van Damme, D.; et al. Conservation status of freshwater mussels in Europe: State of the art and future challenges. Biol. Rev. 2017, 92, 572–607. [Google Scholar] [CrossRef]
  11. Szlauer-Łukaszewska, A.; Ławicki, Ł.; Engel, J.; Drewniak, E.; Ciężak, K.; Marchowski, D. Quantifying a mass mortality event in freshwater wildlife within the Lower Odra River: Insights from a large European river. Sci. Total Environ. 2024, 907, 167898. [Google Scholar] [CrossRef]
  12. Vaughn, C.C. Ecosystem services provided by freshwater mussels. Hydrobiologia 2018, 810, 15–27. [Google Scholar] [CrossRef]
  13. Zieritz, A.; Sousa, R.; Aldridge, D.C.; Douda, K.; Esteves, E.; Ferreira-Rodríguez, N.; Mageroy, J.H.; Nizzoli, D.; Osterling, M.; Reis, J.; et al. A global synthesis of ecosystem services provided and disrupted by freshwater bivalve molluscs. Biol. Rev. 2022, 97, 1967–1998. [Google Scholar] [CrossRef]
  14. Atkinson, C.L.; Hopper, G.W.; Kreeger, D.A.; Lopez, J.W.; Maine, A.N.; Sansom, B.J.; Schwalb, A.; Vaughn, C.C. Gains and gaps in knowledge surrounding freshwater mollusk ecosystem services. Freshw. Moll. Biol. Conserv. 2023, 26, 20–31. [Google Scholar] [CrossRef]
  15. 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; Official Journal of the European Communities (L327); Publications Office of the European Union: Luxembourg, 2000; pp. 1–72.
  16. Raven, P.J.; Holmes, N.T.H.; Dawson, F.H.; Everard, M. Quality assessment using River Habitat Survey data. Aquat. Conserv. 1998, 8, 477–499. [Google Scholar] [CrossRef]
  17. Raven, P.J.; Holmes, N.T.H.; Charrier, P.; Dawson, F.H.; Naura, M.; Boon, P.J. Towards a harmonized approach for hydromorphological assessment of rivers in Europe: A qualitative comparison of three survey methods. Aquat. Conserv. 2002, 12, 405–424. [Google Scholar] [CrossRef]
  18. Szoszkiewicz, K.; Zgoła, T.; Jusik, S.; Hryc-Jusik, B.; Davson, F.H.; Raven, P. Hydromorfologiczna Ocean Wód Płynących. Podręcznik do Badan Terenowych Według Metody River Habitat Survey w Warunkach Polskich; Environment Agency, Poznań-Warrington: Poland, UK, 2012. [Google Scholar]
  19. Song, Y.; Song, S. Assessment of habitats on typical low hills in the Yitong River in Northeast China. J. Freshwater Ecol. 2017, 32, 591–599. [Google Scholar] [CrossRef]
  20. Costa, F.; Vieira, A. Decision Support Tools for River Restoration: The Implementation of the “River Habitat Survey” Methodology on the River Selho (Guimarães Municipality, Northwest Portugal). Hydrology 2021, 8, 69. [Google Scholar] [CrossRef]
  21. Directive 2009/147/EC of the European Parliament and of the Council of 30 November 2009 on the Conservation of Wild Birds (Codified Version); Official Journal of the European Union (L20/7); Publications Office of the European Union: Luxembourg, 2009; pp. 1–19.
  22. Piechocki, A. Mięczaki (Mollusca). Ślimaki (Gastropoda). Fauna Słodkowodna Polski, Zeszyt 7; Państwowe Wydawnictwo Naukowe: Warszawa, Poland, 1979. [Google Scholar]
  23. Piechocki, A.; Dyduch-Falniowska, A. Mięczaki (Mollusca). Małże (Bivalvia). Fauna Słodkowodna Polski 7A; Wydawnictwo Naukowe PWN: Warszawa, Poland, 1993. [Google Scholar]
  24. Glöer, P.; Meier-Brook, C. Süsswassermollusken. Ein Bestimmungsschlüssel für die Bundesrepublik Deutschland; Deutscher Jugendbund für Naturbeobachtung DJN: Hamburg, Germany, 1998. [Google Scholar]
  25. Glöer, P.; Mollusca, I. Süsswassergastropoden. Nord- und Mitteleuropas Bestimmungsschlüssel, Lebensweise, Verbreitung; ConchBooks: Hackenheim, Germany, 2002. [Google Scholar]
  26. Piechocki, A.; Wawrzyniak-Wydrowska, B. Guide to Freshwater and Marine Mollusca of Poland; Bogucki Wydawnictwo Naukowe: Poznań, Poland, 2016. [Google Scholar]
  27. Hermanowicz, W.; Dojlido, J.; Dożańska, W.; Koziorowski, B.; Zerbe, J. Fizyczno-Chemiczne Badanie Wody i Ścieków; Wydawnictwo Arkady: Warszawa, Poland, 1999. [Google Scholar]
  28. Braun-Blanquet, J. Pflanzensoziologie: Grundzüge der Vegetationskunde. Zweite, Umgearbeitete und Vermehrte Auflage; Springer-Verlag: Wien, NY, USA, 1964. [Google Scholar]
  29. Myślińska, E. Grunty Organiczne i Laboratoryjne Metody ich Badania; Wydawnictwo Naukowe PWN: Warszawa, Poland, 2001. [Google Scholar]
  30. Environment Agency. River Habitat Survey in Britain and Ireland. In Field Survey Guidance Manual: 2003 Version; Environment Agency: Bristol, UK, 2003. [Google Scholar]
  31. Environment Agency. Hydromorfologiczna Ocena wód Płynących (River Habitat Survey); Environment Agency: Bristol, UK, 2007.
  32. Szoszkiewicz, K.; Gebler, D. Ocena warunków hydromorfologicznych rzek w Polsce metodą River Habitat Survey. Ochr. Sr. Zasobów Nat. 2011, 47, 70–81. [Google Scholar]
  33. Dziennik Ustaw. Journal of Laws of the Republic of Poland, Item 1475. Regulation of the Minister of Infrastructure of 25 June 2021 on the Classification Of Ecological Status, Ecological Potential and Chemical Status and the Method of Classifying the Status of Surface Water Bodies, as Well as Environmental Quality Standards for Priority Substances. 2021. Available online: https://dziennikustaw.gov.pl/DU/rok/2021/pozycja/1475 (accessed on 12 September 2024).
  34. Stefanidis, K.; Naura, M.; Kouvarda, T.; Latsiou, A.; Gritzalis, K.; Dimitriou, E. Expanding the habitat quality assessment of rivers in Greece using an updated River Habitat Survey toolbox. Ecohydrol. Hydrobiol. 2024, in press. [Google Scholar] [CrossRef]
  35. Tavzes, B.; Urbanič, G. New indices for assessment of hydromorphological alteration of rivers and their evaluation with benthic invertebrate communities; Alpine case study. Rev. Hydrobiol. 2009, 2, 133–161. [Google Scholar]
  36. McCune, B.; Grace, J.B. Analysis of Ecological Communities; MjM Software Design: Gleneden Beach, OR, USA, 2002. [Google Scholar]
  37. Ter Braak, C.J.F.; Šmilauer, P. CANOCO Reference Manual and CanoDraw for Windows User’s Guide: Software for Canonical Community Ordination (Version 4.5), 2nd ed.; Microcomputer Power: Ithaca, NY, USA, 2002. [Google Scholar]
  38. Lopes-Lima, M.; Prié, V.; Aldridge, D.C.; Urbańska, M. Pseudanodonta complanata. The IUCN Red List of Threatened Species. 2024: e.T211999791A212006932. Available online: https://www.iucnredlist.org/fr/species/211999791/212006932 (accessed on 2 September 2024).
  39. Lopes-Lima, M.; Prié, V.; Österling, M.; Zając, T.A. Unio crassus. The IUCN Red List of Threatened Species. 2024: e.T210291828A215467836. Available online: https://www.iucnredlist.org/species/210291828/215467836 (accessed on 2 September 2024).
  40. Council Directive 92/43/EEC of 21 May 1992 on the Conservation of Natural Habitats and Wild Fauna and Flora; Council of the European Communities: Brussels, Belgium, 1992.
  41. Hus, M.; Śmiałek, M.; Zając, K.; Zając, T. Occurrence of Unio crassus (Bivalvia, Unionidae) depending on water chemistry in the foreland of the Polish Carpathians. Pol. J. Environ. Stud. 2006, 15, 169–172. [Google Scholar]
  42. Denic, M.; Stoeckl, K.; Gum, B.; Geist, J. Physicochemical assessment of Unio crassus habitat quality in a small upland stream and implications for conservation. Hydrobiologia 2014, 735, 111–122. [Google Scholar] [CrossRef]
  43. Lewin, I. Mollusc communities of lowland rivers and oxbow lakes in agricultural areas with anthropogenically elevated nutrient concentration. Folia Malacol. 2014, 22, 87–159. [Google Scholar] [CrossRef]
  44. Vaessen, Q.; Houbrechts, G.; Campenhout, V.; Hambuckers, A. Which environmental factors influence the distribution patterns of an endangered freshwater mussel (Unio crassus)? Geomorphology 2024, 454, 109180. [Google Scholar] [CrossRef]
  45. Halabowski, D.; Sousa, R.; Lopes-Lima, M.; Killeen, I.; Aldridge, D.C.; Zając, K.; Mageroy, J.H.; Cossey, D.A.; Urbańska, M.; Österling, M.; et al. Off the conservation radar: The hidden story of Europe’s tiny pea clams (Bivalvia: Sphaeriidae). Biodivers. Conserv. 2024, 33, 3567–3581. [Google Scholar] [CrossRef]
  46. Piechocki, A. Gastropoda aquatica. Ślimaki wodne. In Czerwona Lista Zwierząt Ginących i Zagrożonych w Polsce. Red List of Threatened Animals in Poland; Głowaciński, Z., Ed.; Polish Academy of Sciences, Institute of Nature Conservation: Cracow, Poland, 2002; pp. 34–37. [Google Scholar]
  47. Beran, L.; Horsák, M. Distribution of Bithynia leachii (Sheppard, 1823) and Bithynia troschelii (Paasch, 1842) (Gastropoda: Bithyniidae) in the Czech Republic. Malacol. Bohemosl. 2009, 8, 19–23. [Google Scholar] [CrossRef]
  48. Radulović, S.; Laketić, D.; Vukov, D. A riverside tale: Assessment of altered habitat effects on macrophyte assemblage on the River Tamiš, Serbia. Arch. Biol. Sci. 2010, 62, 1163–1174. [Google Scholar] [CrossRef]
  49. Mouthon, J. Molluscs and biodegradable pollution in rivers: Proposal for a scale of sensitivity of species. Hydrobiologia 1996, 317, 221–229. [Google Scholar] [CrossRef]
  50. Økland, J. Factors regulating the distribution of fresh-water snails (Gastropoda) in Norway. Malacologia 1983, 24, 227–288. [Google Scholar]
  51. Ewald, M.L.; Feminella, J.W.; Lenertz, K.K.; Henry, R.P. Acute physiological responses of the freshwater snail Elimia flava (Mollusca: Pleuroceridae) to environmental pH and calcium. Comp. Biochem. Phys. C 2009, 150, 237–245. [Google Scholar] [CrossRef]
  52. Weber, E. Population size and structure of three mussel species (Bivalvia: Unionidae) in a northeastern German river with special regard to influences of environmental factors. Hydrobiologia 2005, 537, 169–183. [Google Scholar] [CrossRef]
  53. Douda, K. The Occurrence and Growth of Unio crassus (Mollusca: Bivalvia: Unionidae) in Lužnice River Basin in Respect to Water Quality. Acta Univ. Carol. Environ. 2007, 21, 57–63. [Google Scholar]
  54. Meier-Brook, C. Substrate relations in some Pisidium species (Eulamellibranchiata: Sphaeriidae). Malacologia 1969, 9, 121–125. [Google Scholar]
  55. Strayer, D.L. Understanding how nutrient cycles and freshwater mussels (Unionoida) affect one another. Hydrobiologia 2013, 1, 277–292. [Google Scholar] [CrossRef]
  56. Szoszkiewicz, K.; Buffagni, A.; Davy-Bowker, J.; Lesny, J.; Chojnacki, B.H.; Zbierska, J.; Staniszewski, R.; Zgoła, T. Occurrence and variability of River Habitat Survey features across Europe and the consequences for data collection and evaluation. Hydrobiologia 2006, 566, 267–280. [Google Scholar] [CrossRef]
  57. Halabowski, D.; Lewin, I. Triggers for the Impoverishment of the Macroinvertebrate Communities in the Human-Impacted Rivers of Two Central European Ecoregions. Water Air Soil Poll. 2021, 232, 55. [Google Scholar] [CrossRef]
  58. Kiraga, M.J.; Markiewicz, A. A proposed quantitative method for assessing the impact of river regulation on its hydromorphological status. J. Water Land Develop. 2023, 57, 98–106. [Google Scholar] [CrossRef]
  59. Lewin, I.; Jusik, S.; Szoszkiewicz, K.; Czerniawska-Kusza, I.; Ławniczak, A.E. Application of the new multimetric MMI PL index for biological water quality assessment in reference and human-impacted streams (Poland, the Slovak Republic). Limnologica 2014, 49, 42–51. [Google Scholar] [CrossRef]
  60. Szoszkiewicz, K.; Jusik, S.; Lewin, I.; Czerniawska-Kusza, I.; Kupiec, J.M.; Szostak, M. Macrophyte and macroinvertebrate patterns in unimpacted mountain rivers of two European ecoregions. Hydrobiologia 2018, 808, 327–342. [Google Scholar] [CrossRef]
  61. Kiraga, M.J. The Diversification of River Habitat Survey Output During the Four Seasons: Case Studies of Three Lowland Rivers in Poland. J. Ecol. Eng. 2020, 21, 116–126. [Google Scholar] [CrossRef]
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Figure 1. Location of the sampling area. Abbreviations: K1–K6—sampling sections of the river; PLB320008—site code of the Special Protection Area “Ostoja Ińska”; PLH320005—site code of the Special Area of Conservation (SAC) “Dolina Krąpieli”.
Figure 1. Location of the sampling area. Abbreviations: K1–K6—sampling sections of the river; PLB320008—site code of the Special Protection Area “Ostoja Ińska”; PLH320005—site code of the Special Area of Conservation (SAC) “Dolina Krąpieli”.
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Figure 2. Box-and-whisker plot showing the number of mollusc taxa in the river-sampling sections (* significant differences between the sections, the Kruskal–Wallis one-way ANOVA, and multiple comparison post hoc tests, H = 15.88, p = 0.0072).
Figure 2. Box-and-whisker plot showing the number of mollusc taxa in the river-sampling sections (* significant differences between the sections, the Kruskal–Wallis one-way ANOVA, and multiple comparison post hoc tests, H = 15.88, p = 0.0072).
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Figure 3. Box-and-whisker plot showing the density of molluscs in the river-sampling sections (* significant differences between the sections, the Kruskal–Wallis one-way ANOVA, and multiple comparison post hoc tests, H = 19.10, p = 0.0018).
Figure 3. Box-and-whisker plot showing the density of molluscs in the river-sampling sections (* significant differences between the sections, the Kruskal–Wallis one-way ANOVA, and multiple comparison post hoc tests, H = 19.10, p = 0.0018).
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Figure 4. The ordination diagram (biplot) based on a redundancy analysis (RDA) of the mollusc species and the physical and chemical parameters of the water (statistically significant environmental factors are underlined). Abbreviations for mollusc species: Ani leu—Anisus leucostoma; Ano ana—Anodonta anatina; Bat con—Bathyomphalus contortus; Bit lea—Bithynia leachii; Bit ten—Bithynia tentaculata; Gal tru—Galba truncatula; Phy fon—Physa fontinalis; Pis amn—Pisidium amnicum; Pis cas—Pisidium casertanum; Pis mil—Pisidium milium; Pis nit—Pisidium nitidum; Pis per—Pisidium personatum; Pis pon—Pisidium ponderosum; Pis sub—Pisidium subtruncatum; Pis sup—Pisidium supinum; Pla cor—Planorbarius corneus; Pla car—Planorbis carinatus; Pla pla—Planorbis planorbis; Pot ant—Potamopyrgus antipodarum; Pse com—Pseudanodonta complanata; Sph cor—Sphaerium corneum; Sta cor—Stagnicola corvus; Sta pal—Stagnicola palustris; The flu—Theodoxus fluviatilis; Uni cra—Unio crassus; Val pis—Valvata piscinalis; Viv con—Viviparus contectus.
Figure 4. The ordination diagram (biplot) based on a redundancy analysis (RDA) of the mollusc species and the physical and chemical parameters of the water (statistically significant environmental factors are underlined). Abbreviations for mollusc species: Ani leu—Anisus leucostoma; Ano ana—Anodonta anatina; Bat con—Bathyomphalus contortus; Bit lea—Bithynia leachii; Bit ten—Bithynia tentaculata; Gal tru—Galba truncatula; Phy fon—Physa fontinalis; Pis amn—Pisidium amnicum; Pis cas—Pisidium casertanum; Pis mil—Pisidium milium; Pis nit—Pisidium nitidum; Pis per—Pisidium personatum; Pis pon—Pisidium ponderosum; Pis sub—Pisidium subtruncatum; Pis sup—Pisidium supinum; Pla cor—Planorbarius corneus; Pla car—Planorbis carinatus; Pla pla—Planorbis planorbis; Pot ant—Potamopyrgus antipodarum; Pse com—Pseudanodonta complanata; Sph cor—Sphaerium corneum; Sta cor—Stagnicola corvus; Sta pal—Stagnicola palustris; The flu—Theodoxus fluviatilis; Uni cra—Unio crassus; Val pis—Valvata piscinalis; Viv con—Viviparus contectus.
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Figure 5. The ordination diagram (biplot) based on a redundancy analysis (RDA) of the mollusc species and the selected environmental factors (statistically significant environmental factors are underlined). Abbreviations: plants—macrophyte cover of the river channel; organic—percentage of organic matter fraction in the bottom sediments; mineral—percentage of mineral fraction in the bottom sediments; W—sediment sorting; M—mean grain size of sediment (mm). Abbreviations for mollusc species: see Figure 4.
Figure 5. The ordination diagram (biplot) based on a redundancy analysis (RDA) of the mollusc species and the selected environmental factors (statistically significant environmental factors are underlined). Abbreviations: plants—macrophyte cover of the river channel; organic—percentage of organic matter fraction in the bottom sediments; mineral—percentage of mineral fraction in the bottom sediments; W—sediment sorting; M—mean grain size of sediment (mm). Abbreviations for mollusc species: see Figure 4.
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Figure 6. The ordination diagram (biplot) based on a redundancy analysis (RDA) of the mollusc species and the selected physical attributes of the river and the channel vegetation type concerning the RHS method (statistically significant environmental factors are underlined). Abbreviations: OG—exposed boulders; EB—eroding cliff; SU—vegetated mid-channel bar; Zr(S)—gravel; WW—submerged linear-leaved macrophytes. Abbreviations for mollusc species: see Figure 4.
Figure 6. The ordination diagram (biplot) based on a redundancy analysis (RDA) of the mollusc species and the selected physical attributes of the river and the channel vegetation type concerning the RHS method (statistically significant environmental factors are underlined). Abbreviations: OG—exposed boulders; EB—eroding cliff; SU—vegetated mid-channel bar; Zr(S)—gravel; WW—submerged linear-leaved macrophytes. Abbreviations for mollusc species: see Figure 4.
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Figure 7. The ordination diagram (biplot) based on a redundancy analysis (RDA) of the mollusc species and the indices concerning the RHS method (statistically significant environmental data are underlined). Abbreviations for indices: HQA—the Habitat Quality Assessment; HMS—the Habitat Modification Score; RHQ—the River Habitat Quality; RHM—the River Habitat Modification. Abbreviations for mollusc species: see Figure 4.
Figure 7. The ordination diagram (biplot) based on a redundancy analysis (RDA) of the mollusc species and the indices concerning the RHS method (statistically significant environmental data are underlined). Abbreviations for indices: HQA—the Habitat Quality Assessment; HMS—the Habitat Modification Score; RHQ—the River Habitat Quality; RHM—the River Habitat Modification. Abbreviations for mollusc species: see Figure 4.
Water 16 03448 g007
Table 1. The values of the environmental factors (ranges) in the river-sampling sections K1–K6 (* superscript denotes significant differences between the sections, the Kruskal–Wallis one-way ANOVA, and multiple comparison post hoc tests).
Table 1. The values of the environmental factors (ranges) in the river-sampling sections K1–K6 (* superscript denotes significant differences between the sections, the Kruskal–Wallis one-way ANOVA, and multiple comparison post hoc tests).
Parameter/
Unit		K1K2K3K4K5K6H-Valuep-Value
Temperature
[°C]		10.3–21.39.8–20.411.3–22.612.1–22.812.2–21.612.4–19.07.040.2173
Conductivity
[µS cm−1]		142–188
*K5,6		158–208
*K6		157–242
*K6		188–242195–246
*K1		205–345
*K1,2,3		25.620.0001
Turbidity
[mg dm−3]		9.5–42.49.5–38.317.2–61.06.0–85.021.3–68.20.0–44.69.190.1016
Dissolved oxygen
[mg O2 dm−3]		6.5–10.4
*K2		1.6–6.3
*K1,5,6		6.3–8.4
*K6		5.1–8.6
*K6		6.2–9.8
*K2		7.3–9.7
*K2,3,4		35.540.0001
pH6.84–12.0
*K2		5.98–7.0
*K1,4,6		6.0–10.856.46–12.80
*K2		6.78–12.607.14–8.45 *K215.820.0074
Ammonium nitrogen
[mg N–NH4+ dm−3]		0.10–0.560.18–2.480.28–0.70
*K5,6		0.25–0.410.18–0.34
*K3		0.18–0.40
*K3		17.940.0030
Nitrates
[mg NO3− dm–3]		0.93–5.76
*K5		3.31–5.760.10–5.940.75–7.463.49–7.13
*K1		0.46–6.7012.870.0247
Phosphates
[mg PO43– dm−3]		0.02–0.25
*K2		0.24–0.75
*K1		0.13–0.710.26–0.490.04–1.300.04–0.3115.030.0103
Iron
[mg Fe dm−3]		0.06–0.200.10–0.290.14–0.41
*K4,6		0.02–0.10
*K3		0.09–0.350.08–0.37
*K3		23.560.0003
Hardness
[mg CaCO3 dm−3]		44–217103–208103–256118–23190–171127–28813.560.0186
BOD5
[mg O2 dm−3]		0.0–8.1
*K2,3,4,5		0.0–5.6
*K1		2.3–5.1
*K1		3.7–5.5
*K1		1.4–6.1
*K1		3.7–6.219.240.0017
Velocity
[m s−1]		0.003–0.3970.011–0.2500.001–0.5890.124–0.3580.004–0.6720.047–0.5415.210.3911
Insolation
[%]		1.37–45.42
*K2		100.0–100.01
*K1,3,5		3.60–86.67
*K2		3.93–81.211.41–35.17
*K2		0.62–99.9225.960.0001
Organic
[%]		0.35–2.501.07–32.750.64–25.990.59–9.390.61–1.750.28–3.637.540.1835
Mineral
[%]		97.51–99.6567.25–98.9374.01–99.3690.61–99.4198.25–99.3996.37–99.727.540.1835
Macrophytes
cover		00–50–50–300–210.960.0522
Mean grain size of sediment M [mm]0.44–3.600.03–2.650.14–3.320.14–2.930.44–3.320.14–3.326.560.2551
Sediment sorting
W [%]		0.30–1.750.94–1.750.53–1.750.94–1.380.37–1.380.13–1.2710.290.0673
Table 2. The structure of mollusc communities and the values of the Shannon–Wiener index H′ in the river-sampling sections K1–K6. Abbreviations: R—riffle, P—pool.
Table 2. The structure of mollusc communities and the values of the Shannon–Wiener index H′ in the river-sampling sections K1–K6. Abbreviations: R—riffle, P—pool.
Sampling Sections of the Krąpiel River
Taxa/SpeciesK1K2K3K4K5K6
RPRPRPRPRPRP
Theodoxus fluviatilis 50.6877.5030.9946.156.25 57.14
Viviparus contectus 3.550.51
Bithynia leachii1.14 0.358.23
Bithynia tentaculata51.14 24.8229.31 7.696.25 21.05
Potamopyrgus antipodarum 5.83 6.25
Valvata piscinalis 2.74
Galba truncatula 15.38
Radix juv. 15.79
Stagnicola corvus1.14
Stagnicola palustris1.14
Stagnicola sp.2.275.00
Physa fontinalis 2.74
Anisus leucostoma 47.37
Bathyomphalus contortus 7.14
Gyraulus sp. 1.41
Planorbarius corneus5.68 3.1910.281.37
Planorbis carinatus2.27
Planorbis planorbis 1.03
Anodonta anatina 1.41
Pseudanodonta complanata 2.82 7.69
Unio crassus 4.23
Unio sp. 1.41
Pisidium amnicum 2.742.501.4130.7718.7515.387.145.26
Pisidium casertanum10.2325.00 3.332.82 4.76
Pisidium milium 0.26
Pisidium nitidum6.8215.00 5.149.59 4.23 4.76
Pisidium personatum 35.00 5.48 2.38
Pisidium ponderosum 2.82
Pisidium subtruncatum
Pisidium supinum1.145.00 9.596.6726.76 12.50 7.14
Pisidium sp.9.0915.00 5.665.48 8.45 7.69 10.53
Sphaerium corneum7.95 68.0939.599.594.1711.2715.3850.0053.859.52
Ʃ specimens882028238973120711316134219
Ʃ taxa126591061346585
The Shannon-Wiener
index H′		2.482.281.242.272.441.272.861.742.081.882.151.97
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Lewin, I.; Śmietana, P.; Pakulnicka, J.; Stryjecki, R.; Stępień-Zawal, E.; Pešić, V.; Bańkowska, A.; Szlauer-Łukaszewska, A.; Michoński, G.; Achrem, M.; et al. Application of the River Habitat Survey Method in the Assessment of the Human Pressure Within the Lowland River Catchment: The Mollusc Biodiversity Versus Habitat Features. Water 2024, 16, 3448. https://doi.org/10.3390/w16233448

AMA Style

Lewin I, Śmietana P, Pakulnicka J, Stryjecki R, Stępień-Zawal E, Pešić V, Bańkowska A, Szlauer-Łukaszewska A, Michoński G, Achrem M, et al. Application of the River Habitat Survey Method in the Assessment of the Human Pressure Within the Lowland River Catchment: The Mollusc Biodiversity Versus Habitat Features. Water. 2024; 16(23):3448. https://doi.org/10.3390/w16233448

Chicago/Turabian Style

Lewin, Iga, Przemysław Śmietana, Joanna Pakulnicka, Robert Stryjecki, Edyta Stępień-Zawal, Vladimir Pešić, Aleksandra Bańkowska, Agnieszka Szlauer-Łukaszewska, Grzegorz Michoński, Magdalena Achrem, and et al. 2024. "Application of the River Habitat Survey Method in the Assessment of the Human Pressure Within the Lowland River Catchment: The Mollusc Biodiversity Versus Habitat Features" Water 16, no. 23: 3448. https://doi.org/10.3390/w16233448

APA Style

Lewin, I., Śmietana, P., Pakulnicka, J., Stryjecki, R., Stępień-Zawal, E., Pešić, V., Bańkowska, A., Szlauer-Łukaszewska, A., Michoński, G., Achrem, M., Krakowiak, M., Zawadzki, D., Chatterjee, T., & Zawal, A. (2024). Application of the River Habitat Survey Method in the Assessment of the Human Pressure Within the Lowland River Catchment: The Mollusc Biodiversity Versus Habitat Features. Water, 16(23), 3448. https://doi.org/10.3390/w16233448

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