Development of a macroinvertebrate-based biotic index to assess water quality of rivers in Niger State, North Central Ecoregion of Nigeria.

The increasing pollution of lotic ecosystems in sub-Saharan Africa, particularly in Nigeria, poses a threat to water quality, public health and biodiversity. It is therefore essential to develop appropriate tools and methods for monitoring these rivers, particularly in heavily affected areas, where these water resources are vital to the surrounding communities that are heavily dependent on them. To fill this gap, we propose to develop a multimetric index based on macroinvertebrates for the assessment of ecological quality of rivers in Niger State (NSRBI). Eighty-eight metrics were evaluated through a step-by-step statistical process (namely, range test and stability, redundancy test and relationship with abiotic variables), in which metrics that did not meet the conditions were excluded. At the end of this process, only four metrics (%Hemiptera, Diptera richness, Pielou equitability and % of very large individuals (size > 40 mm)) fulfilling all criteria were included in the index. These metrics were then scored on a continuous scale and divided into four water quality classes: "very poor", "poor", "fair" and "good". Evaluation of the performance of the index on test sites showed a correspondence of 90% between index result and environmental-based classification. Therefore, the NSRBI could be a valuable tool for monitoring and assessing the ecological conditions of rivers in Niger State and the North Central Nigeria ecoregion predominantly in urban and agricultural landscapes.

Development of lake macroinvertebrate-based multimetric index for monitoring ecological health in North Central Nigeria.

The use of organisms like macroinvertebrates in developing bioassessment tools, such as multimetric indices (MMIs), is gaining global recognition in monitoring the health status of lakes. The transition from traditional methods of physico-chemical parameters is due to the financial and time costs involved in their analysis while failing to provide accurate early warning signals on ecosystem conditions. Currently, there is scanty information on the use of MMIs in the conservation and management of lakes in Nigeria. This study aimed at developing a macroinvertebrate-based MMI to assess the ecological status of lakes in North Central Nigeria. The study was conducted on Tagwai and Old Gawu Lakes, from April to October 2022. Sampling sites were clustered based on organic pollution and categorized into reference (four) and impaired (four) sites. Out of 54 macroinvertebrate-based candidate metrics, only five were selected after discriminatory, stability, and redundancy tests (performed using R software). The final metrics were abundance of Ephemeroptera + Trichoptera; abundance of Coleoptera + Ephemeroptera; Gastropoda richness; Shannon Wiener index; and percentages of shredders + predators + scrapers, hereafter referred to as North Central Nigeria-Lakes Multimetric Index (NCN-LMMI). The NCN-LMMI values ranged as follows: 21-25, 16-20, 11-15, and 5-10 corresponding to categories I, II, III, and IV for water quality, as indications of good, fair, poor, and very poor ecological status of the lake, respectively. The developed NCN-LMMI will be a useful tool for aquatic resource managers and environmentalists to assess the ecological condition of lakes, mainly the North Central Nigeria municipal lakes.

Mining and urbanization affect river chemical water quality and macroinvertebrate communities in the upper Selenga River Basin, Mongolia.

Mongolia is a country with a quickly growing economy mainly based on mining of gold, copper, coal, and other minerals. Mining, urbanization, and agriculture impact the water quality in the upper Selenga River Basin in northern Mongolia, which is the center of the Mongolian economy. Previous measurements of pollution loads were alarming, but restricted to chemical measurements. Here, for the first time, we combine freshwater biomonitoring and laboratory water quality data across a broad gradient of water quality and land use intensity. We track the effects of different types of pollution on aquatic invertebrates and test their use as bioindicators. We collected water samples, environmental parameters, and macroinvertebrates at 36 sampling sites at the rivers of Tuul, Kharaa, and Orkhon and their tributaries Sugnugur, Boroo, Sharyn Gol, Gatsuurt, and Yeröö. PCA of catchment water quality distinguished three groups of pollutants prevalent at the sites: (1) nutrients, (2) saline components (Cl-, Na +, Mg2+, SO42-, Ca2+) and mining by-products (B, Sr, U, Mo), and (3) (heavy) metals, which often exceeded regulatory standards. We recorded a total of 59 macroinvertebrate taxa belonging to 32 families in seven insect orders plus Amphipoda and Gastropoda. Species diversity declined with higher impact. Five environmental factors structured macroinvertebrate community composition in RDA: elevation of sample location, site total nitrogen, dissolved oxygen, electrical conductivity, and water chemistry. We conclude that macroinvertebrate communities are an appropriate and inexpensive tool for monitoring water quality in Mongolia and suggest government action to establish a long-term monitoring program.

Morphological vs. DNA metabarcoding approaches for the evaluation of stream ecological status with benthic invertebrates: Testing different combinations of markers and strategies of data filtering.

Macroinvertebrate assemblages are the most common bioindicators used for stream biomonitoring, yet the standard approach exhibits several time-consuming steps, including the sorting and identification of organisms based on morphological criteria. In this study, we examined if DNA metabarcoding could be used as an efficient molecular-based alternative to the morphology-based monitoring of streams using macroinvertebrates. We compared results achieved with the standard morphological identification of organisms sampled in 18 sites located on 15 French wadeable streams to results obtained with the DNA metabarcoding identification of sorted bulk material of the same macroinvertebrate samples, using read numbers (expressed as relative frequencies) as a proxy for abundances. In particular, we evaluated how combining and filtering metabarcoding data obtained from three different markers (COI: BF1-BR2, 18S: Euka02 and 16S: Inse01) could improve the efficiency of bioassessment. In total, 140 taxa were identified based on morphological criteria, and 127 were identified based on DNA metabarcoding using the three markers, with an overlap of 99 taxa. The threshold values used for sequence filtering based on the "best identity" criterion and the number of reads had an effect on the assessment efficiency of data obtained with each marker. Compared to single marker results, combining data from different markers allowed us to improve the match between biotic index values obtained with the bulk DNA versus morphology-based approaches. Both approaches assigned the same ecological quality class to a majority (86%) of the site sampling events, highlighting both the efficiency of metabarcoding as a biomonitoring tool but also the need for further research to improve this efficiency.

Evaluation of the impact of heterogeneous environmental pollutants on benthic macroinvertebrates and water quality by long-term monitoring of the buyuk menderes river basin.

Biomonitoring is a significant method for evaluating aquatic life forms and their environments. The longer the process continues, the results of it become more precise. Benthic macroinvertebrates' exposure to changes in environmental conditions makes them an important part of any biomonitoring program. This paper reviews a long-term water quality of the Buyuk Menderes River Basin which is the biggest river basin spread across the western Anatolia (Turkey). The study area was divided into three regions (Usak, Aydin, Denizli), primarily considering the provincial borders in the basin. A total of 40 sampling sites from the main river and its tributaries were selected. The prominent agricultural and industrial pollutants (textile, tannery and sugar factories) from each region have been taken into account. The most common and current biotic indices (BMWP Spanish version, ASPT, RBPIII, MMIF, EPT%, Diversity and Evenness) based on the pollution tolerance of benthic macroinvertebrates have been used to track water quality changes. The relationships between environmental variables (sO2, dO2, water temp., salinity, flow, TDS, Cond, pH, NO3-N, NO2-N, PO4-P, Fe+3, NH4-N) and bioindicators have been revealed by using multivariate analyses (NMDS, CCA). The region-based variations in water quality were compared with the Kruskal-Wallis test. The one-way variance analysis test (ANOVA) was used for the contrast between the biotic indices. Significant differences (p < 0.05) were found among the regions in terms of Shannon-Wiener, Evenness, BMWP and MMIF indices. Regions were separated according to pollution sources, and the impact of provinces on water quality may vary according to their industry types. It has been observed that pollutants can spread across a basin for very long distances and reinstatement of the environmental conditions may require long periods.

Seasonal and spatial variations in the phytoplankton community and their correlation with environmental factors in the Jinjiang River Estuary in Quanzhou, China.

The seasonal and spatial variation in the phytoplankton community structure and the environmental variables were investigated in December (the dry season) 2016 and July (the rainy season) 2017 in the Jinjiang River Estuary, China. We identified a total of 138 species of phytoplankton, which were mainly Chlorophyta, Bacillariophyta, and Cryptophyta in the dry season; however, in the rainy season, only Bacillariophyta were found. In the Jinjiang River Estuary, the species evenness and the biodiversity index were higher in the rainy season and that the species diversity was higher in the dry season. Redundancy analysis (RDA) revealed that the dominant species were statistically related to many of the environmental variables, including the water temperature (WT), pH, salinity (Sal), dissolved oxygen (DO), total phosphorus (TP), and total nitrogen (TN). Among the variables, the Sal, DO, TP, and TN had a significant influence on the dominant species distribution, and the WT and pH also affected the dominant species distribution to some extent.

The Impact of Metal-Rich Sediments Derived from Mining on Freshwater Stream Life.

Metal-rich sediments have the potential to impair life in freshwater streams and rivers and, thereby, to inhibit recovery of ecological conditions after any remediation of mine water discharges. Sediments remain metal-rich over long time periods and have long-term potential ecotoxicological interactions with local biota, unless the sediments themselves are physically removed or replaced by less metal-rich sediment. Laboratory-derived environmental quality standards are difficult to apply to the field situation, as many complicating factors exist in the real world. Therefore, there is a strong case to consider other, field-relevant, measures of toxic effects as alternatives to laboratory-derived standards and to seek better biological tools to detect, diagnose and ideally predict community-level ecotoxicological impairment. Hence, this review concentrated on field measures of toxic effects of metal-rich sediment in freshwater streams, with less emphasis on laboratory-based toxicity testing approaches. To this end, this review provides an overview of the impact of metal-rich sediments on freshwater stream life, focusing on biological impacts linked to metal contamination.

The use of macroinvertebrate based biotic indices and diversity indices to evaluate the water quality of Lepenci river basin in Kosovo.

Benthic macroinvertebrates are used to evaluate water quality in 8 sampling stations in Lepenci river basin in Kosovo. Sampling was performed in spring, summer and fall 2017. Following biotic indices are used: EPT taxa richness, Biological Monitoring Working Party (BMWP), Average Score per Taxon (ASPT), Stroud Water Research Center index (SWRC), Family biotic index (FBI), as well as diversity indices: Shannon-Weaver index (H), Simpsons index (D), Hill's index (Hi), Mergalef index (DMe) and Menhicnik's index (DMa). Our results show the presence of 34 macroinvertebrate taxa in Lepenci river which belong to Insecta, Crustaceans and Annelidae. The water quality along the river show variation from high and good class upstream, to moderate, poor and bad, downstream. The Pearson's bivariate correlation used to analyze the relationship between physicochemical parameters with biotic and diversity indices showed a significant correlation (p < 0.01) of EC, TSS, O2, COD, BOD, NH4, and PO43- with biotic indices EPT, BMWP, ASPT, SWRC, FBI. We can conclude that the values of biotic and diversity indices have shown differences in water quality between polluted and unpolluted sites and reflect the ecological status of the river, therefore we can consider them as valuable tools for water quality assessment in rivers in Kosovo.

Coarse taxonomy (tolerance-value averaging) biases Hilsenhoff's family-level biotic index.

Hilsenhoff's family-level index (FBI) combines information about the relative abundances of taxa and their tolerances to pollution. Versions of this index are used extensively in North America to assess water quality. When faced with constraints on time, money, or expertise, bioassessment practitioners have been tempted to calculate a version of the FBI with very coarse (e.g., order-level) taxonomy. Such an approach requires a degree of within-taxon averaging of tolerance values and raises questions about the degree to which accuracy is compromised and bias is introduced. Data from thousands of streams in Ontario (Canada) demonstrated that such tolerance-value averaging produces index scores and associated water-quality classifications that are not equivalent to those calculated with the standard family-level taxonomic precision. Two methods were used in an attempt to correct the order-level FBI scores to equivalence with the family-level index: (1) tolerance scores for the orders included in the calculation were calculated as abundance-weighted means of the scores of their component families, and (2) order-level FBI scores were estimated as predicted values from a polynomial regression of the two versions of the index. The use of abundance-weighted mean tolerance scores greatly improved the accuracy of the order-level index, and the regression-based correction reduced bias by equalizing the distribution of errors across the range of observed FBI values. Nonetheless, equivalence of scores was not demonstrated, and water quality was misclassified in 12 to 80% of cases. Practitioners are discouraged from the practice of tolerance-value averaging and are advised to adhere to the standard family-level FBI.

Use of macroinvertebrate assemblages for assessing performance of stabilization ponds treating effluents from sugarcane and molasses processing.

Wastewater discharge from sugarcane processing is a significant pollutant of tropical aquatic ecosystems. For most developing countries, monitoring of the level of pollutants is done mostly through chemical analysis, but this does not reflect potential impacts on aquatic assemblages. In addition, laboratory facilities for accurate concentration measurements are often not available for regular monitoring programs. In this study, we investigated the use of benthic macroinvertebrates for biological monitoring in western Kenya. Benthic macroinvertebrates were sampled in stabilization ponds treating wastewater from sugarcane- and molasses-based processing plants to assess their composition and abundance in relation to different concentrations of chemical variables. Optimum concentrations and tolerance values were identified for various taxa, and a biotic index was developed that combined tolerance values (ranked between 0 and 10) for the various macroinvertebrate taxa. A succession in composition and distribution of macroinvertebrate taxa was observed from the inlet to the outlet of the pond systems. Diptera dominated in the first ponds that had high concentrations of chemical oxygen demand (COD), biological oxygen demand (BOD5), and nutrients, while intolerant Ephemeroptera, Plecoptera, and Trichoptera (EPT) appeared as the concentrations dropped in subsequent ponds. The effluent quality was classified as "good," "fair," and "poor," corresponding with biotic index value ranges 0-3.50, 3.51-6.50, and 6.51-10, respectively. During validation, the index grouped sites with respect to levels of measured environmental variables. The study revealed that the developed biotic index would help in monitoring the quality of sugarcane processing and molasses effluents before release into recipient aquatic ecosystems, replacing the need for costly chemical analyses.

TICI: a taxon-independent community index for eDNA-based ecological health assessment.

Global biodiversity is declining at an ever-increasing rate. Yet effective policies to mitigate or reverse these declines require ecosystem condition data that are rarely available. Morphology-based bioassessment methods are difficult to scale, limited in scope, suffer prohibitive costs, require skilled taxonomists, and can be applied inconsistently between practitioners. Environmental DNA (eDNA) metabarcoding offers a powerful, reproducible and scalable solution that can survey across the tree-of-life with relatively low cost and minimal expertise for sample collection. However, there remains a need to condense the complex, multidimensional community information into simple, interpretable metrics of ecological health for environmental management purposes. We developed a riverine taxon-independent community index (TICI) that objectively assigns indicator values to amplicon sequence variants (ASVs), and significantly improves the statistical power and utility of eDNA-based bioassessments. The TICI model training step uses the Chessman iterative learning algorithm to assign health indicator scores to a large number of ASVs that are commonly encountered across a wide geographic range. New sites can then be evaluated for ecological health by averaging the indicator value of the ASVs present at the site. We trained a TICI model on an eDNA dataset from 53 well-studied riverine monitoring sites across New Zealand, each sampled with a high level of biological replication (n = 16). Eight short-amplicon metabarcoding assays were used to generate data from a broad taxonomic range, including bacteria, microeukaryotes, fungi, plants, and animals. Site-specific TICI scores were strongly correlated with historical stream condition scores from macroinvertebrate assessments (macroinvertebrate community index or MCI; R2 = 0.82), and TICI variation between sample replicates was minimal (CV = 0.013). Taken together, this demonstrates the potential for taxon-independent eDNA analysis to provide a reliable, robust and low-cost assessment of ecological health that is accessible to environmental managers, decision makers, and the wider community.

Comparison of different macroinvertebrates bioassessment indices in a large near-natural watershed under the context of metacommunity theory.

The metacommunity theory proposes that community structure and biodiversity are influenced by both local processes (such as environmental filtering) and regional processes (such as dispersal). Despite the extensive use of traditional bioassessments based on species-environment relationships, the impact of dispersal processes on these assessments has been largely overlooked. This study aims to compare correlations between various bioassessment indices, including Shannon Weiner (H'), Biological Monitoring Working Party (BMWP), average score per taxon (ASPT), biotic index (BI), and EPT taxa index (EPT), based on macroinvertebrates collected from 147 sampling sites in a subtropical Chinese near-natural catchment. Modified indices were calculated by removing species strongly influenced by dispersal processes to address the influence of dispersal processes. Their relationship with environmental factors was then compared to the original indices. The study employed random forest regression (RFR) to compare the explanatory power of environmental factors using the two sets of indices. The spearman rank correlation analysis was conducted to examine the correlation between indices and environmental factors. The river health assessment was performed based on both modified and original indices. The results reveal significant differences between original and modified indices (especially H' and BI) providing a more accurate reflection of environmental conditions. Furthermore, the sensitivity of the different indices to various environmental factors varied, leading to differences in the bioassessment results between the modified and the original indices. Notably, original H', BMWP, and ASPT overestimated the bioassessment results, whereas the original BI underestimated them. These findings offer valuable insights into bioassessment and river health assessment evaluation within the catchment and other interconnected freshwater ecosystems, such as lakes, reservoirs, and wetlands. Our study underscores the importance of assessing and mitigating the impact of dispersal processes on bioassessment to obtain a more precise representation of the status of freshwater ecosystems.

Identifying Active Rather than Total Methanotrophs Inhabiting Surface Soil Is Essential for the Microbial Prospection of Gas Reservoirs.

Methane-oxidizing bacteria (MOB) have long been recognized as an important bioindicator for oil and gas exploration. However, due to their physiological and ecological diversity, the distribution of MOB in different habitats varies widely, making it challenging to authentically reflect the abundance of active MOB in the soil above oil and gas reservoirs using conventional methods. Here, we selected the Puguang gas field of the Sichuan Basin in Southwest China as a model system to study the ecological characteristics of methanotrophs using culture-independent molecular techniques. Initially, by comparing the abundance of the pmoA genes determined by quantitative PCR (qPCR), no significant difference was found between gas well and non-gas well soils, indicating that the abundance of total MOB may not necessarily reflect the distribution of the underlying gas reservoirs. 13C-DNA stable isotope probing (DNA-SIP) in combination with high-throughput sequencing (HTS) furthermore revealed that type II methanotrophic Methylocystis was the absolutely predominant active MOB in the non-gas-field soils, whereas the niche vacated by Methylocystis was gradually filled with type I RPC-2 (rice paddy cluster-2) and Methylosarcina in the surface soils of gas reservoirs after geoscale acclimation to trace- and continuous-methane supply. The sum of the relative abundance of RPC-2 and Methylosarcina was then used as specific biotic index (BI) in the Puguang gas field. A microbial anomaly distribution map based on the BI values showed that the anomalous zones were highly consistent with geological and geophysical data, and known drilling results. Therefore, the active but not total methanotrophs successfully reflected the microseepage intensity of the underlying active hydrocarbon system, and can be used as an essential quantitative index to determine the existence and distribution of reservoirs. Our results suggest that molecular microbial techniques are powerful tools for oil and gas prospecting.

A review of the application of the macroinvertebrate-based multimetric indices (MMIs) for water quality monitoring in lakes.

The increasing stress on lake ecosystems is affecting their functioning such as providing goods and services to inhabiting organisms and riparian communities. Monitoring of water quality is important for sustainable management and restoration of lake ecosystems. However, the costs associated with traditional approaches have become prohibitive, while not giving reliable early warning signals on resource conditions. Thus, the current shift in the use of bioindicators and multimetric indices (MMIs) in the monitoring of water quality is currently gaining global recognition with more emphasis on its application in lotic ecosystems. Therefore, this paper provides an elaborated insight into the application of macroinvertebrate-based MMIs in lentic ecosystems and the successes achieved so far. The various metrics and indices, the development strategies, application challenges, the use of macroinvertebrates as bioindicators, and the future projection of enhancing MMI usage in lentic environment monitoring, particularly in developing countries, are extensively covered. The use of MMI as a rapid lake biomonitoring tool needs to be adopted for sustainable applications in lake ecosystem management and as an integrated approach to monitoring human-induced stress especially in developing countries where there is a paucity of information.

New Species and Conservation Status of the Genus Group Scotussae (Orthoptera: Acrididae) in the Atlantic Forest.

Two new brachypterous species of the genus Scotussa, with restricted distributions, are described for one of the most important and greatly threatened biodiversity hotspots, the Atlantic Forest. These species belong to the genus group Scotussae, a diverse group regarding mobility and oviposition habits. It has been mentioned that these characteristics could lead to restrictions in the species distribution. Based on these antecedents and considering the importance of biodiversity conservation within the Atlantic Forest, we performed novel conservation indices for this group. The rapid assessment indices calculated herein are based upon Red List status, endemism, dispersal capacity, and life-history traits that allowed us to identify areas for conservation for this group of grasshoppers. For a better understanding of the conservation status of the group, the results of the indices were compared with protected areas and Key Biodiversity Areas. Moreover, historical biome stability was also considered since it has been associated with different distributional and diversification patterns within the genus group Scotussae. The approach applied indicates that the indices recovered different but complementary information. The Grasshopper Biotic Index (GBI) determined important regions for conservation within the richest region of the group while the GBI/SiteScore located regions with lower diversity values for the group but with high importance regarding endemisms.

Natural and anthropogenic factors and their interactions drive stream community integrity in a North American river basin at a large spatial scale.

Urbanization, agriculture, and other human activities can exert considerable influence on the health and integrity of stream ecosystems. These influences vary greatly over space, time, and scale. We investigated trends in stream biotic integrity over 19 years (1997-2016) in relation to natural and anthropogenic factors in their spatial context using data from a stream biomonitoring program in a region dominated by agricultural land use. Macroinvertebrate and fish diversity and abundance data were used to calculate four multimetric indices (MMIs) that described biotic integrity of streams from 1997 to 2016. Boosted regression trees (BRT), a machine learning technique, were used to model how stream integrity responded to catchment-level natural and anthropogenic drivers including land use, human population density, road density, runoff potential, and natural factors such as latitude and elevation. Neither natural nor anthropogenic factors were consistently more influential on the MMIs. Macroinvertebrate indices were most responsive to time, latitude, elevation, and road density. Fish indices were driven mostly by latitude and longitude, with agricultural land cover among the most influential anthropogenic factors. We concluded that 1) stream biotic integrity was mostly stable in the study region from 1997 to 2016, although macroinvertebrate MMIs had decreased approximately 10% since 2010; 2) stream biotic integrity was driven by a mix of factors including geography, human activity, and variability over yearly time intervals; 3) MMI responses to environmental drivers were nonlinear and often nonmonotonic; 4) MMI composition could influence causal inferences; and 5) although our findings were mostly consistent with the literature on drivers of stream integrity, some commonly seen patterns were not evident. Our findings highlight the utility of large-scale, publicly available spatial data for understanding drivers of stream biodiversity and illustrate some potential pitfalls of large scale, integrative analyses.

Responses of the benthic environment to reduction in anthropogenic nutrient loading in the Seto Inland Sea (Japan), based on M-AMBI assessment.

Deterioration of the sediment environment and benthic ecosystem is an undesirable effect of eutrophication, but little is known about the response of macrobenthic communities to eutrophication and their long-term recovery. In the present study, temporal changes in benthic ecological status, associated with reductions in anthropogenic impacts on a largest semi-enclosed sea in Japan, were determined using long-term monitoring data from water and sediment quality based on the multivariate AZTI Marine Biotic Index (M-AMBI), focusing on spatial differences in anthropogenic impacts. Several sub-areas were classified based on Chlorophyll a (Chl.a) concentrations in surface water during the 1980s. Chl.a concentrations decreased in all sub-areas except the sub-area with <2 µg Chl.a L-1 from the 1990s-2010s. On the other hand, total organic carbon contents in sediment decreased and M-AMBI values increased in all sub-areas during this period may be due to reduced lateral organic matter advection from surrounding areas.

Functional diversity of macrofaunal assemblages as indicators to assess heavy metal pollution in the Bohai Sea, China.

Functional diversity of macrofaunal assemblages can reflect the composition and differences of functional traits, indicating their response to various contaminants, especially heavy metal pollution. We explored the effects of environment variables over gradients of heavy metal pollution on macrofaunal assemblages, using biological traits analysis, generalized linear model (GLM), AZTI marine biotic index (AMBI), and various biodiversity indexes. The RLQ (co-inertia analysis) and fourth-corner approaches were used to investigate the specific response of functional traits to heavy metal pollution. Most sites were environmentally degraded by heavy metal pollution and macrofaunal body size had a miniaturization trend. There was a significant correlation between functional diversity indexes and AMBI. The RLQ and fourth-corner analysis and GLM models showed that heavy metal and natural environmental gradients had a profound effect on functional diversity. The functional divergence and dispersion indexes, along with the abundance of some specific species, were appropriate indexes for heavy metal pollution.

Response of different benthic biotic indices to eutrophication and sediment heavy metal pollution, in fujian coastal water, East China sea.

The types and intensity of anthropogenic pressure in the same sea area may differ spatially and may change as time passes, but response of benthic biotic indices to different pressure is different, which makes it unreasonable to use the same benthic biotic indices in a large sea area. We provided a new way of thinking as to selecting benthic biotic indices according to pressure type. The study took six bays under eutrophication and sediment heavy metal pollution to different levels in Fujian coastal water, East China sea, as examples, analysed the response of five benthic biotic indices, namely AZTI marine biotic index (AMBI), multivariate AMBI (M-AMBI), Shannon-Wiener diversity index (H'), benthic opportunistic polychaetes amphipods (BOPA) and benthic polychaetes amphipods (BPA), to eutrophication factors and sediment heavy metal pollution factors firstly. The result indicated that AMBI well responded to dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP); M-AMBI responded soundly in the range of DIN >0.131 mg L-1 and DIP >0.022 mg L-1 and responded universally to heavy metals; H' responded to only Hg and Cd; BOPA has response to eutrophication condition of DIN >0.242 mg L-1; BPA had response to DIN, Cu and As. Then, suitable indices were selected based on the four pressure scenarios in the study area. AMBI was selected in no pressure scenario; M-AMBI was chosen under only eutrophication pressure and under dual pressure; H' was preferred in only heavy metal pressure scenario (mainly Hg pollution). At last, the density plot of the distribution of the selected indices in the evaluation grades under different pressure scenarios proved the proposal of selecting benthic biotic indices according to pressure types feasible. This study can offer some new insights into rapidly choosing indices to evaluate the coastal benthic ecological quality status.

Highway stormwater ponds as islands of Odonata diversity in an agricultural landscape.

Stormwater management ponds, which are constructed to retain excess runoff and pollutants from traffic, play an important role in the freshwater biodiversity in highly modified areas. However, their roles in agricultural and semi-natural landscapes remain largely unexplored. In this study, we used Odonata as a bioindicator to compare a set of highway stormwater ponds and surrounding ponds within an agricultural and semi-natural landscape to examine the extent to which stormwater ponds act as biodiversity refuges. We analyzed the differences in environmental parameters and the richness, compositions, and conservation values of the odonate communities of stormwater and surrounding ponds. We also examined the factors controlling the differences in the communities of both pond types. The stormwater ponds were smaller, less eutrophicated, less shaded by trees, less stocked with fish, and less connected with other waterbodies than the surrounding ponds. However, they had a higher plant diversity and pH values and were more densely overgrown with vegetation. Compared with surrounding ponds, stormwater ponds had a higher Odonata richness and ß-diversity, but their taxonomic distinctness was significantly lower. Therefore, stormwater ponds hosted more variable communities but their assemblages were taxonomically similar. Indicator species were only identified in stormwater ponds. Furthermore, stormwater ponds harbored more species with higher conservation values. The most important factors affecting the differences between stormwater and surrounding ponds were the trophic state, relative tree shading, and fish stocking intensity. With their increase, the richness and rarity decreased. Our results highlight the potential of stormwater ponds to enhance the biodiversity outside urban areas by providing specific habitat conditions that are unique to the surrounding agricultural landscape. In addition, we suggest management practices that can be used to enhance their biodiversity conservation function.