Macrophyte Index Research Articles

Linking carbon storage with land use dynamics in a coastal Ramsar wetland

Coastal wetland ecosystems make an important contribution to the global carbon pool, yet their extent is declining due to aquaculture-related land use changes. We conducted an extensive investigation into the carbon stock and area coverage of macrophytes in a tropical coastal Ramsar wetland, Kolleru in Andhra Pradesh, India. A total of 72 quadrats of size 1 × 1 m2 were laid in the wetland, 19 species of macrophytes were collected and analyzed for carbon content using a CNHS analyzer. To assess changes in the wetland macrophytes, Normalized Difference Vegetation Index (NDVI) was estimated using Landsat time series data from 1975 to 2023. The importance value index (IVI) of macrophytes scored highest for the Ipomoea aquatica (41.4) and the lowest for Ottelia alismoides (1.9). Non-metric multidimensional scaling (NMDS) significantly (r = 0.1905, p = 0.0361) revealed a clear separation of macrophytes in ordination space. ANOVA indicated highly significant (p < 0.0001) variations in the carbon content of aboveground and belowground components of macrophytes. Among the different macrophytes, the highest carbon content was found in Phragmites karka (0.6 g. g−1) and the lowest was recorded in Utricularia stellaris (0.2 g. g−1). On an average, emergents in the Kolleru wetland sequester 1525 ± 181 g C m−2 yr−1, rooted floating species sequester 858 ± 101 g C m−2 yr−1, submerged macrophytes sequester 480 ± 60 g C m−2 yr−1, and free-floating macrophytes sequester 221 ± 90 g C m−2 yr−1. Land cover mapping revealed a decrease in spread of aquatic vegetation from 225.2 km2 in 1975 to 100.6 km2 in 2023. Although macrophytes are vital carbon sinks, the wetland conversion into fishponds has resulted in a loss of 55.3 % of carbon storage. Therefore, immediate restoration of macrophyte cover is vital for the proper functioning of carbon sequestration and mitigation of climate change impacts.

Structure of the macrophyte communities of small rivers in Saratov under anthropogenic load

The article presents the results of investigations of the flora of small rivers within the city of Saratov (Yelshanka, Nazarovka, 1st Gusyolka, and 2nd Gusyolka). The species composition of aquatic plants of the streams studied is represented by 37 macrophyte species belonging to 23 genera, 17 families and three divisions (Charophyta, Polypodiophyta, and Magnoliophyta). The families Potamogetonaceae, Cyperaceae and Lemnaceae predominate by the number of represented species. The values of the Menchinik index indicate that the greatest floristic diversity is characteristic of the Yelshanka and Nazarovka rivers (3.1 and 3.4, respectively). The species composition of aquatic plants of the studied rivers within the urban area has a low similarity coefficient with the flora of rivers with relatively low anthropogenic load. Hydrophytes are the most numerous ecological group (22 species). According to the Paley–Kownacki dominance index, among the macrophytes of the studied rivers, most species are subdominant (57.28%) (Potamogeton perfoliatus, Typha angustifolia, Lemna trisulca, etc.). 37.18% (Phragmites australis, Potamogeton pectinatus, Lemna minor, Ceratophyllum demersum) belong to dominants, and the rest (11.54%) is defined as subdominants of the first order. Exceptional predominance is characteristic of Ceratophyllum demersum and Phragmites australis, which acted as dominants in all studied rivers. A significant part of the rivers is characterized by a low degree of overgrowth by hydrophilous vegetation, from slightly overgrown to not overgrown. The main types of distribution of aquatic and riparian-water vegetation are belted and fragmentary. Macrophyte communities are characterized by a simplified structure (one- or two-tiered), with absolute predominance of one plant species and the presence of two to four associated species with low values of projective coverage. The results of our calculations of indices (macrophyte index for small rivers (Sm), Indice Biologique Macrophytique in Riviere (IBMR)) based on the structural parameters of macrophytes showed that the studied rivers have a satisfactory ecological status.

Determination of the macrophyte index MIR as an indicator of water quality in the Pripet river

Introduction. The river basin and the catchments of small rivers within it is a complete ecological, hydrological and economic unit with clear boundaries and a set of natural conditions. Increasing the stability of the geosystem of the river basin is impossible without monitoring the dynamics of the state of natural resources and factors of negative impact. A significant part of the water management complex of the Volyn region is the Pripet River basin which has a significant degree of development. The watercourse forms part of the state border between Ukraine and the Republic of Belarus, the tributary basins are located on the territory of both states. The source, lower course and mouth of the Pripet River are on the territory of Ukraine. Therefore, it is necessary to observe the strategic principles of rational nature management to restore and preserve the optimal ecological state of the Pripet River basin. The objective of the work is to assess the ecological state of the Pripet River using bioindication methods and the Macrophyte Index for Rivers (MIR). Methods. Research methods are expeditionary, mathematical statistics, bioindication, and determination of the Macrophyte Index for Rivers (MIR). Results. Four test sites of at least 100 m length each were used to determine the ecological state of the waters of the Pripet River. Research found 48 species of higher aquatic and coastal aquatic plants in the test sites of the Pripet River. All species belong to the division Magnoliophyta, of which 21 species of the class Magnoliopsida (43.75%), and the larger share (27 species, 56.25%) to the class Liliopsida. 35 indicative species of macrophytes were selected in the test sites of the river to determine the Macrophyte Index for Rivers (MIR). According to the MIR classification, the river belongs to lowland watercourses, the macrophyte type M-VIII (organic rivers). MIR calculations established that the river water quality in the test site No. 1 (village of Polozhevo, upper reaches) has a satisfactory ecological state, MIR is 33.84; in the site No. 2 (v. Luchytsi) satisfactory ecological state, MIR is 34.04; in the site No. 3 (v. Liubyaz, border between Volyn and Rivne regions) good ecological state, MIR is 40.6; water quality in the site No. 4 (v. Senchytsi, border with Belarus) has satisfactory ecological state, MIR is 33.57. Conclusions. According to the Macrophyte Index for Rivers, it was established that the Pripet River waters have a satisfactory or good ecological state. This gives reason to state that the research in the test sites and the MIR calculations fully reflect the ecological state of the watercourse, which allows the use of this research algorithm for other rivers of the basin.

Ecological assessment of pit lakes in Raniganj, India: Application of different indices and multivariate statistics

ABSTRACT Coal mine generated open pit lakes are well distributed in Raniganj coal field area, West Bengal, India. This paper screened out ecological state macrophyte index (ESMI), water quality index (WQI) and multivariate statistical methods to assess the ecological status of four pit lakes, Nagrakonda, Joyalbhanga, Dalurbandh, and Kumardihi. Seven water quality parameters (pH, total dissolved solids, dissolved oxygen, Secchi depth nitrate, chloride, and phosphate) and six sediment quality parameters (pH, organic carbon, bulk density, particle density, available nitrogen and phosphorus) were analyzed for one year on a monthly basis from four pit lakes. The abundance and diversity of aquatic macrophytes were also analyzed. In the studied pit lakes, water and sediment quality variables showed significant spatial variation. WQI showed that the water quality in all pit lakes was good and according to ESMI these lakes were categorized into good ecological status. The results of this study indicated the values of water quality and macrophyte based indices highlighted the ecological condition of the pit lakes of the study sites thus should be considered it as reliable tool for assessing of the ecological status of any wetlands.

River Macrophyte Index for ecological status assessment of the non-karst and Dinaric karst waters

Assessing the ecological status of surface waters is essential for evaluating the ecosystem health and for defining of river basin management strategy. River Macrophyte Index (RMI) is uniformly used for assessing the trophic status of rivers and was intercalibrated for Mediterranean and Eastern-Continental lowland rivers in European Union but not for Dinaric karst rivers. Karst rivers are specific due to extreme water level fluctuations that might reflect in macrophyte communities' response. We built a composite stressor gradient as a proxy for trophic status, classified 85 plant species in the ecological indicator groups using large, representative data set, separately examined sites from karst and non-karst rivers and validated updated River Macrophyte Index (RMIup) with the independent data set. We found the differences in the response of macrophyte communities of karst and non-karst waters to the composite stressor gradient what resulted in type-specific boundary values. RMI reference values were significantly higher for karst waters in comparison to non-karst waters, but the normalised boundary values were similar for both water types indicating that key shifts in macrophyte communities occur at similar deviations along the stressor gradient. Boundary values of the updated RMI differed from those from the original RMI version as lower normalised RMI values were observed using the updated RMI version, but only at high to moderate ecological status sites. The updated RMI is showing a good relationship with the composite stressor gradient using the development and validation dataset and provides us with an effective assessment system and river management tool.

Macrophytes As Indicators Of The Ecological Status Of Valaam Island Small Lakes System

The article evaluates the ecological status of five small lakes on Valaam Island (Igumenskoe, Chernoe, Ossievo, Nikonovskoe, Krestovoe) using macrophytes as bioindicators. The methods proposed by Finland, Sweden, and Norway were used, to assess the state of eutrophication, the change in the composition of specific species, the change in the water level, and the state of acidification, according to different indexes (Reference index (RI), Trophic Macrophyte Index (TMI), Trophic Index (TIc), the Proportion of Type– Specific Taxa (PTST), the Percent Model Affinity (PMA), Water level Index (WIc), and Acidification Index (SIc)). An analysis of the floristic composition for the period 2011 – 2020 was realized, including taxonomic analysis, ecogroup, and macrophyte diversity. The dominant taxon was Elodea canadensis Michx. in Igumenskoe, Chernoe, Ossievo lakes and Calla palustris L. in Nikonovskoe and Krestovoe lakes. The ecogroup hygrohelophyte was the most diverse in all lakes studied. The ecological status of the lakes according to each assessed parameter reflects that all lakes are characterized by a mesotrophic to eutrophic state, there is a variation in species composition of macrophyte and no water level change or acidification processes are presumed to occur in any of the lakes. In general, each method has its limitations, but it is suggested to continue studies for the RI, TMI, PTST, and PMA indices, and to integrate them with other national physicochemical or biological indices.

Correlation between catchment land use/cover and macrophyte assessment of lake ecological status

The Water Framework Directive (WFD) provides the basis for developing a system to protect and restore the aquatic environment. Macrophytes are one of the groups of organisms for determining ecological status of lakes. Using partial least squares regression (PLS-R), we showed relationships between conductivity and chlorophyll a (to a lesser extent nutrient concentrations) and Ecological State Macrophyte Index (ESMI) values. However, catchment land use/cover (LU/LC) appears to be the important factor affecting macrophyte diversity as expressed by ESMI. The presence of significant correlations was found for the catchment area determined from surface runoff using the platform SCALGO Live, based on a permanently updated numerical terrain model and an accurate land use/cover database used in Poland BDOT10k. The Corine Land Cover (CLC) database commonly used in the EU appeared to be of insufficient resolution. We have shown a high positive impact of the presence of wetlands and reservoirs in the catchment on ESMI values and negative for agricultural and urbanized areas. Obtaining information on lake catchment land use and land cover is costless. Relating LU/LC to lake macrophyte assessment methods allows this no-cost method to be included in the set of biological methods for assessing lake condition. Understanding the factors that determine the condition of lakes is fundamental to managing them according to the requirements of the WFD. The results of our study indicate that the integration of lake catchment area planning with lake water management is imperative.

Assessment of the environmental state of surface waters of the Stokhid river by Macrophyte Index MIR

Assessment of the environmental state of surface waters of the Stokhid river by Macrophyte Index MIR

Ecological Quality Assessment of Greek Lowland Rivers with Aquatic Macrophytes in Compliance with the EU Water Framework Directive

Aquatic macrophytes are one of the four biological quality elements (BQE) used for assessing the ecological status of inland waters according to the EU Water Framework Directive (WFD 2000/60). With this article, we present the methodological approach for the implementation of a WFD compliant macrophyte index to the riverine systems of Greece. In addition to the definition and harmonization of the ecological quality class boundaries, the results from the pilot application of the index and the ecological classification of the monitored river reaches are also presented. Aquatic plants and environmental parameters were sampled from 93 river reaches between 2012 and 2015. A multivariate analysis with optimal scaling (MVAOS) was conducted to define the main stressor gradient and to identify the least disturbed sites and the reference conditions that are required for the derivation of the ecological quality classes. The Macrophyte Biological Index IBMR for Greek rivers (IBMRGR) was calculated for all the sites and the boundaries for the five quality classes were derived according to the methodology proposed by the Mediterranean Geographic Intercalibration Group (MedGIG). The main findings showed that the hydromorphological modifications were the main environmental stressors that correlated strongly with the IBMRGR, whereas physicochemical stressors were of lesser importance. More specifically, the first principal component explained 51% of the total variance of the data, representing a moderately strong gradient of hydromorphological stress, whereas the second component explained 22.5%, representing a weaker gradient of physicochemical stress. In addition, the ecological assessment showed that almost 60% of the sites failed the WFD target of the “Good” ecological quality class, which agrees with classification assessments based on other BQEs for Greece and many Mediterranean countries. Overall, this work provides a first assessment of the ecological classification of Greek rivers with the BQE of aquatic macrophytes with significant implications for ecological monitoring and decision making within the frame of the WFD implementation.

Assessment of the environmental state of surface waters of right-bank tributaries of the upper reaches of the Pripet River by macrophyte index MIR

Assessment of the environmental state of surface waters of right-bank tributaries of the upper reaches of the Pripet River by macrophyte index MIR

The Macrophyte Indices for Rivers to Assess the Ecological Conditions in the Klina River in the Republic of Kosovo.

Macrophytes are important elements of aquatic ecosystems that grow in or near water. Their taxonomic composition, species diversity, depth, and density are indicators of environmental health; as such, Macrophytes are used to assess the ecological status of water bodies. Under the aim of assessing the ecological status of the Klina River in Kosovo, a survey was conducted at eight sampling sites along the river course to analyze macrophyte composition, diversity, density, and cover. Three samples were collected at each sampling site from early June to late September. The following macrophyte indices were used to assess the ecological status of the river: Macrophyte Index for Rivers (MIR), River Macrophyte Nutrient Index (RMNI), and River Macrophyte Hydraulic Index (RMHI). Our sampling area included the upper reaches of the river where no organic pollution was detected (oligotrophic), the middle reaches where polluted water from farms is discharged into the river, and the lower reaches characterized by heavy organic pollution from settlements and various industrial activities. There is a positive correlation (p < 0.05) between water temperature, turbidity, electrical conductivity (EC), total dissolved solids (TDS), orthophosphates (PO43−), ammonia (NH4+), nitrites (NO2−), calcium (Ca2+), and potassium (K+) with plant density, RMNI, RMHI, EQR-RMNI, EQR-RMHI, and MIR. Sodium (Na+) has stronger positive correlation (p < 0.01) with RMNI and RMHI indices and negative correlation with EQR-RMNI and EQR-RMHI. Our results show that ecological status along the river varies from high and good upstream to poor, bad, and moderate running downstream.

Macrophyte communities as indicators of the ecological status of drainage canals and regulated rivers (Eastern Poland)

Macrophytes are one of the biological elements for assessing the ecological status. Macrophyte communities were studied in six artificial (drainage canal and ditches) or modified watercourses (regulated rivers). In order to assess the ecological status of the watercourses, studies were carried out with the use of the Macrophyte Index for Rivers (MIR) proposed in the Water Framework Directive. Macrophyte communities were mainly represented by helophytes (12 species in total), and the highest percentage area cover (50–75% of the site) was observed for pleustophytes (Lemna spp.). Macrophytes communities were affected by the gradients of hydromorphological (canal modification, flow type, and shading) and parameters water quality (nutrients and water transparency). The relationships were highly species-specific. In accordance with the MIR values, the ecosystems were classified as having poor (drainage canal), moderate (regulated rivers), or good (drainage ditches) ecological status.

Long-Term Changes in Macrophyte Distribution and Abundance in a Lowland River.

The aim of this study was to reveal the changes of macrophyte community over time and along the course of the Ižica River. In 1996, 2000, and 2016, we surveyed the distribution and abundance of macrophyte species in the lowland Ižica River, which originates in the town of Ig and then flows through an agricultural landscape. We calculated the River Macrophyte Index (RMI), which reflects the ecological status of the river. In 2016, ecomorphological conditions of the river, using the Riparian, Channel and Environmental inventory, were also assessed. In just 10.5 km of the river, we identified 27 taxa of macrophytes, among which Potamogeton natans, Sagittaria sagittifolia, and P. perfoliatus were the most abundant. Detrended correspondence analysis showed that, in 1996, the surveyed stretches differed more according to macrophyte composition than in the following years. The assessed environmental parameters explained 43% of the variability of the macrophyte species; riverbank stability explained 20%, riverbed structure 10%, while vegetation type of the riparian zone and bottom type explained 7 and 5%, respectively. The species composition of the macrophyte community revealed significant changes over the years of the riverine ecosystem. Comparison of RMIs in 1996 revealed better conditions in the upper and middle part of the river, while in 2016, the situation was the opposite, since the conditions in the upper part deteriorated significantly over time, while the lower part of the river had the best ecological status. These changes may be due to a considerable increase in the population of the settlement Ig, while better status in the lower course of the river may be a consequence of improvements in the infrastructure and the use of sustainable agricultural practices in the catchment due to the establishment of a formal area of protection.

Non-Linear Visualization and Importance Ratio Analysis of Multivariate Polynomial Regression Ecological Models Based on River Hydromorphology and Water Quality

Multivariate polynomial regression (MPR) models were developed for five macrophyte indices. MPR models are able to capture complex interactions in the data while being tractable and transparent for further analysis. The performance of the MPR modeling approach was compared to previous work using artificial neural networks. The data were obtained from hydromorphologically modified Polish rivers with a widely varying water quality. The modeled indices were the Macrophyte Index for Rivers (MIR), the Macrophyte Biological Index for Rivers (IBMR), and the River Macrophyte Nutrient Index (RMNI). These indices measure the trophic and ecological status of the rivers. Additionally, two biological diversity indices, species richness (N) and the Simpson index (D), were modeled. The explanatory variables were physico-chemical properties depicting water quality and river hydromorphological status indices. In comparison to artificial neural networks, the MPR models performed similarly in terms of goodness of fit. However, the MPR models had advantages such as model simplicity and ability to be subject to effective visualization of complex nonlinear input–output relationships, as well as facilitating sensitivity analysis using importance ratios to identify effects of individual input variables.

Responses of Freshwater Diatoms and Macrophytes Rely on the Stressor Gradient Length across the River Systems

Phytobenthic diatoms and macrophyte communities respond differently to stressors in aquatic environments. For the assessment of the ecological status of rivers in Slovenia, we use several indices, including the River Macrophyte Index (RMI) and Trophic index (TI) based on macrophyte and phytobenthic diatoms communities, respectively. In the present study, we examined the relationships between nutrient variables and values of RMI and TI using varied stressor gradient lengths. We also aimed to explain the variability of macrophyte and diatom communities with different stressors, namely nutrients and land cover variables and their combinations. The relationships of RMI and TI with nutrient variables varied significantly and were affected by the length of the stressor gradient. We obtained a stronger relationship between the RMI and total phosphorous at an approximately &lt;0.3-mg/L annual mean value, while, for the relationships with the TI, the values were significant at bigger gradient lengths. The greatest share of variability in the macrophyte and diatom community was explained by the combination of land use and nutrient variables and the lowest share by phosphorus and nitrogen variables. When we applied a composite stressor gradient, it explained a similar share of the variability of both macrophyte and diatom communities (up to 26%). A principal component analysis (PCA) based on land use and nutrient stressor gradient revealed that the relationship between RMI EQR and PCA1 that represents intensive agriculture depends on the length of the gradient. The relationship was stronger for shorter gradients at lower values and decreased as the gradient extended towards higher values. Both tested assessment methods showed that macrophyte communities are more sensitive to shorter stressor gradients of lower values, whereas diatom communities are more sensitive to longer stressor gradient and higher values of the stressor.

Local habitat is a strong determinant of spatial and temporal patterns of macrophyte diversity and composition in boreal lakes

Abstract Macrophyte species and trait assemblages from 104 minimally disturbed boreal forest lakes, covering broad environmental and geographic gradients were analysed to identify associations with environmental variables at different spatial scales: geographic context (GEO) and catchment (CATCH) and lake (LOCAL) characteristics. Constrained ordination and variation partitioning were used to quantify variation in species (canonical correspondence analysis [CCA] and pCCA) and trait (redundancy analysis [RDA] and pRDA) compositions that could be explained by environmental variables, and to rank the main environmental factors associated with spatial and temporal patterns. Diversity and assemblage composition correlated with spatial context and variables related to the length of the growing season, catchment forest type and with lake characteristics such as ecosystem size, lake productivity and alkalinity. Variation partitioning showed that lake characteristics alone explained 53% (species) and 73.5% (traits) of the variability in macrophyte assemblages. Contrary to predictions, the shared variance component between latitude and catchment forest type (GEO&amp;CATCH &lt; 0.1% for both species and traits) and between latitude and lake characteristics (GEO&amp;LOCAL = 6.7% for species and 3.9% for traits) was low. Temporal variability, measured as changes in species richness, diversity and a pollution‐specific index (the Trophic Macrophyte Index), using a subset of the lakes sampled on two occasions (19 lakes sampled in 2012 and 2018 and five lakes sampled in 2013 and 2019) did not differ (p &gt; 0.05, paired t‐test). Ordination showed that among‐year variability in macrophyte assemblage composition was also negligible (0.3%) compared to the variability explained by GEO, CATCH and LOCAL variables. Combined, these findings indicate low species turnover in the boreal lakes of our study. Responses of macrophyte species and trait assemblages and the TMI index were predictable and significantly correlated with lake characteristics associated with nutrient enrichment (Chl a, nutrients) and alkalinity supporting their use in monitoring eutrophication of boreal lakes.

Multimetric Index to Evaluate Water Quality in Lagoons: A Biological and Geomorphological Approach

In recent years, Multimetric Indices (MMIs) have received a lot of attention thanks to their ability to develop integrative evaluations of water quality, particularly in lagoons. In this article, we propose a new MMI for determining the water quality in lagoons. The proposed index is composed of biotic and abiotic indicators, in particular macroinvertebrates, macrophytes and morphological indicators. The proposed index is based on a geometric representation of a phenomenon associated with an ecological system, the ecosystem elements are mapped as vertices of a network and the relationship between them is represented by the corresponding edges. We classify the status of water bodies, from very low to very high using the ecological quality ratio. We compare our index with different different indices that measure water quality, such as General Biotic Index (JP(G)), Macrophyte Index for River (MIR) and Shannon diversity index (H’) and validate our index with Pearson’s correlation coefficient. A strong correlation with the JP(G) and MIR indices (R2 = 0.8605 and R2=0.7661, respectively) is obtained. Although the proposed index is composed of other indices, the independence of the proposed index with respect to its component indices is proven and the structure of the geometric model associated to the proposed network is studied. A close relationship between the measure called medium articulation and the geometric model associated with the proposed index is highlighted, which allows to determine the missing relationships in the network using structural analysis. The proposed index presents a more comprehensive measure than most indices currently used and has the advantage in the scalability, since other existing indicators can be integrated into our model.

Assessment of the ecological condition of the Western Bug river basin according to the macrophyte index for rivers (MIR)

Introduction. To restore and preserve the optimal ecological status of the Western Bug river basin, it is necessary to adhere to the strategic principles of environmental management, and since the river is transboundary and tributary basins are located in Ukraine and Poland, it is important to determine the ecological status of small rivers. In the territory of the Volyn region, the rivers-tributaries Luha and Studyanka are most affected by anthropogenic impact. An ecological assessment of water quality based on the condition of macrophytes is given, as macrophytes llow to determine the degree of surface water degradation, first of all, in terms of their trophic status. The purpose of article. The purpose of article aims to assess the ecological status of the rivers of the Western Bug river basin using bioindication methods and determination of the Macrophyte Index for Rivers (MIR). Methods. Research methods are expeditionary, methods of mathematical statistics end bioindication methods and determination of the Macrophyte Index for Rivers (MIR). Results. To determine the ecological status of the rivers of the Western Bug basin and to conduct research, three test sites with a length of at least 100 m were laid on two tributaries of the first order - the rivers Luha and Studyanka. To determine the MIR (Macrophyte Index for Rivers) in the test riverbed areas, 42 indicator species of macrophytes were selected, of which 1 species belongs to the division Polipodiophyta and Equisetophyta, 40 species to the division Magnoliophyta, of which 15 belong to the class Magnoliopsida, and 25 belong to the class Liliopsida. According to the classification of the MIR indicator, to determine the ecological status, the rivers Luha and Studyanka belong to lowland watercourses, with the type of macrophytes - M-VIII (organic rivers). As a result of the calculated Macrophyte Index for Rivers (MIR), it was established (Table 4) that the water quality in the Luha river in test site 1 (Zavydiv village) has a good ecological status, MIR is 39,0; and test site 2 (Volodymyr-Volynskyi city) has a satisfactory or moderate ecological status, MIR is 31,56; in the river Studyanka, the test site 3 (Ustyluh town) has a satisfactory or moderate ecological condition, MIR is 28,31. Conclusions. According to the ecological status of rivers determined by the Macrophyte Index for Rivers (MIR), it is established that the waters of the Luha and Studyanka rivers have a satisfactory or moderate ecological condition. This suggests that the research conducted on test sites and calculations of the Macrophyte Index for Rivers (MIR) are identical and fully reflect the ecological status of the rivers Luha and Studyanka determined by hydrochemical parameters, which allows the use of this research algorithm for other rivers in the Western Bug river basin and is promising during research on other rivers of Ukraine.

Macrophytes as indicators of the ecological status of a tropical rehabilitated wetland ecosystem: Application of multivariate statistics and Ecological State Macrophyte Index (ESMI)

The present study used the Ecological State Macrophyte Index (ESMI) and the multivariate statistical methods to assess the ecological status and the variation of macrophytes in a tropical wetland system. Six sites were selected from rehabilitated and non-rehabilitated areas of an urban tropical wetland and the water quality parameters (water pH, temperature, conductivity, total dissolved solids (TDS), dissolved oxygen (DO), visibility, biological oxygen demand 5 days after incubation (BOD 5 ), chemical oxygen demand (COD), nitrate, chlorophyll-a and total phosphorus concentrations), sediment quality parameters (pH, organic matter content, percentage sand, silt and clay content) and abundance of aquatic macrophytes were measured. Shannon Weiner diversity index, percentage vegetation under anthropo-pressure, macrophyte settlement rate and ESMI were calculated. Significant variations in the water and sediment quality parameters were observed and ten species of aquatic macrophytes were recorded. Salvinia melosta and Cypreus iria were recorded only from the non-rehabilitated sites. Although there was no significant difference in the percentage anthropo-pressure among study sites, the rehabilitated sites were displayed low anthropo-pressure. The sites in the non-rehabilitated area showed a significantly lower macrophyte settlement rate. ESMI and macrophyte abundance showed significant correlations with water quality parameters. Based on the results, it can be recommended that applications based on ESMI and multivariate statistics can be used to assess the ecological status of tropical wetlands.

Freshwater macroalga, Ulva pilifera (Ulvaceae, Chlorophyta) as an indicator of the trophic state of waters for small water bodies

Mass occurrence of green algae of the genus Ulva in the form of algal blooms (known as “green tides”) is often associated with high concentrations of biogens in the water. Therefore, Ulva species are most often used in monitoring seawater trophy and far less frequently freshwater trophy. In Europe, the biomonitoring of river ecosystems is based on aquatic plants. According to the River Macrophyte Index (RMI), river populations of Ulva macroalgae (only tubular Enteromorpha-like Ulva) are considered good indicators for eutrophic waters. This paper analyses the legitimacy of using U. pilifera as a trophy indicator in the case of ponds. It has been noted that freshwater populations of U. pilifera are much more common in lakes, dammed reservoirs, or ponds than in rivers. In this study, analysed populations of U. pilifera originated from 14 ponds located in central Poland. Data analysis relied on the Carlson Trophic State Index (CTSI), which was compared with other known trophic indices. According to CTSI values, U. pilifera was most common in eutrophic ponds, where the mean concentrations of ammonium nitrogen, nitrates, total phosphorus, and chlorophyll a reached 581, 241, 212, and 20 µg·L−1, respectively. The results indicate that U. pilifera can be considered a bioindicator for eutrophic waters (50–70 of CTSI). It would therefore be appropriate to introduce U. pilifera as part of biomonitoring conducted in small bodies of water. Major arguments in favour of practical application of U. pilifera are: (i) it is a large macroalga, the thalli of which can reach a length of > 1.0 m, (ii) it is an easy-to-identify species; even by non-experts (it is characterized by a distinctive tubular shape of the thallus), and (iii) it occurs in bulk in conditions of eutrophy, creating an easily observable bloom.