Family-level Biotic Index Research Articles

IMPACT OF ECOHYDROLOGICAL INTERVENTIONS ON MACROINVERTEBRATE DIVERSITY ASSOCIATED WITH PHYSICOCHEMICAL PARAMETERS ON THE WETLANDS ALONG THE SOUTHEASTERN SHORE OF LAKE TANA, ETHIOPIA

Biological indicators have the improvement of monitoring ecological conditions and to measure of anthropogenic impacts on aquatic ecosystems. This indicates that appropriate wetland management mitigation measures that should be implemented in degraded wetlands to conserve biodiversity and improve water quality. The aim of the study was to investigate the impacts of ecohydrological intervention in relation to macroinvertebrate diversity and relate macroinvertebrate diversity with physicochemical parameters of the wetland in Lake Tana shore intervention site. Sampling stations were selected according to vegetation gradient. The sampling procedure employed using quadrats along transects following the main ecological gradient of water depth and vegetation structure and growth form. Four quadrats at every 25m distance were laid at each transect. A total of 24 quadrats of 1m x1m size were taken. Collected samples of each quadrat were pooled to represent each sampling site. One way ANOVA was further done to test any significant variation in macroinvertebrate and physiochemical attributes among stations. The Hilsenhoff Family-level Biotic Index (HFBI) was calculated for macroinvertebrate families. The HFBI index was analyzed and identified 975 macroinvertebrate individuals belonging to 15 families which were collected from all sampling sites during the study period, and the most dominant family were Hydrophilidae Coenagrionidae and Physidae. Based on the Shannon diversity index, the Gumetirs wetland was grouped under good ecological condition as compared to the remaining two reference wetlands. There was a significant variation in abundance and biodiversity of macroinvertebrates among sampling sites and better conditions exist at the intervention site. The correlation analysis between physicochemical parameters and macro-invertebrate abundance showed that organic carbon and temperature are most likely positively correlated with macroinvertebrate abundance. Thus, high macroinvertebrate diversity indicated that wetlands found in a good ecological condition.

Bioindicator Based Water Quality Assessment of Warbo and Dabo Streams in Awash Catchment, Dendi Woreda, Ethiopia

The present study was aimed at assessing the water quality of Warbo and Dabo streams in awash catchment using macroinvertebrates as biological indicators. The status of water quality was assessed in terms of presence or absence of indicator organisms in relation to physico-chemical parameters. Hilsenhoff Family-level Biotic Index (H-FBI) results have shown that the site 6 had relatively higher value (6.5) followed by site 5 (5.8). The site 1 recorded least H-FBI value which accounts for 3.2 followed by site 4 (3.74). For ETHbios index, highest score was recorded at site 3 (120) followed by site 4 (102) while the lowest score was obtained for the site 6 and site 1 which accounts for 54 and 57 respectively. The ASPT value was comparatively higher for sites 1 (6.67) and site 3 (6.31) than other sites. Principal components analysis of physico-chemical variables showed wide variation among the study sites. Axis 1 and axis 2 of the PCA explained 97.5% of the total variance regarding the sites versus physico-chemical association, where the first axis and second axis contributed 73.04% and 24.56% to the variation, respectively. Results of Pearson correlation reaveled that there exists significant relation between variuos pollutant parameters.

Effect of Environmental Stressors on the Distribution and Abundance of Macroinvertebrates in Upper Awash River at Chilimo Forest, West Shewa, Ethiopia

Ethiopia is experiencing deterioration in river quality resulting in adverse effects on human health and hydrobionts. This study aimed to analyse the effects of specific environmental stressors on the distribution and abundance of macroinvertebrates in the Upper Awash River. The study was conducted from January 2018 to March 2018. Macroinvertebrates were collected from five sites using standard handheld nets. Physicochemical parameters including electrical conductivity, dissolved oxygen, total phosphorous, nitrate-nitrogen, pH, dissolved oxygen and water temperature that can affect the distribution and abundance of macroinvertebrates were assessed. A total of 14,465 individuals belonging to 33 families of insects and 5 families of the noninsect group were identified. Among all recorded taxa, Diptera was the most abundant and diversified order. Macroinvertebrates among the five sites showed variation in species evenness, richness, and Shannon Diversity Index. Values obtained from biotic indices and environmental parameters indicated the presence of organic pollution at different levels. The impacted downstream site paper mill waste (Walgata) had the relatively highest H-FBI index followed by Osole (more agricultural activities) indicating that Walgata and Osole were poorer in benthic faunal diversity than other sites. In addition, as habitat and water quality degradation increased, the number and percentage of Plecoptera, Ephemeroptera, and Trichoptera (EPT) decreased. The selected metrics will be also useful for the monitoring and assessment of the riverine systems and to access the impact of different stressors. As perturbation increased, species diversity, ETHbios index, Average Score Per Taxon, and family richness decreased, while the percentage of Chironomidae, Diptera, Dominant Taxa, and Hilsenhoff Family-Level Biotic Index increased indicating that tolerant species become abundant in degraded river bodies. Environmental protection agencies of governmental and nongovernmental organizations should make awareness for the local people so that they reduce activities that affect the river. Paper factory should also monitor its effluent from directly discharging into the Upper Awash River.

Development of a predictive model for benthic macroinvertebrates by using environmental variables for the biological assessment of Korean streams

Predictive models for benthic macroinvertebrates based on changes in environmental variables can assess the biological integrity of streams by comparing observed biotic communities with those expected at reference sites. To develop a predictive model of the abiotic community, we used benthic macroinvertebrates and environmental variables collected from 2,700 sites from 2010 to 2019. First, we selected 357 reference sites by using the 5-day biochemical oxygen demand, ammonia nitrogen, total phosphorus, turbidity, and coarse particle percentage. Then, we used Two-Way Indicator Species Analysis to classify the reference sites into six groups based on benthic macroinvertebrates. Reference sites classified by biological characteristics were linked to environmental variables by multi-discriminant analysis. The relative influences environmental variables on the classified groups were in decreasing order of catchment area, latitude, velocity, water depth, altitude, and longitude. To develop the predictive model, we combined (1) identification level, (2) grouping method, and (3) probability of capture, and then used the normalized root mean square error (NRMSE) to check the fit of each model. The higher the probability of capture was at the family level compared to the species level, the lower was the NRMSE. The grouping method was not as consistent as the identification level and probability of capture because the NRMSE for the number of taxa was low when used as a weighted average. The NRMSE was also low for the Benthic Macroinvertebrates Index and the Benthic Macroinvertebrates Family-level Biotic Index (BMFI) when used for assignment to the group with the highest probability. We selected the predictive model which used family level, weighted average, and BMFI-proposed indicator taxa as the final assessment model due to its sensitivity and fit. This model was the most reasonable choice, but we had to reduce the error of the model and revise it elaborately by securing additional environmental variables.

Health evaluation of riverine ecosystems using aquatic macroinvertebrates: a case study of the Mohammad-Abad River, Iran

Macroinvertebrates can provide an integrated picture of environmental changes. Health of rivers can be assessed based on measured changes in the ecological structure of macroinvertebrates. Using aquatic macroinvertebrates, we evaluated health of Mohammad-Abad River located in Golestan Province of Iran. Twelve sampling stations were selected along the river. Macroinvertebrates were sampled, and physicochemical parameters were measured at the same time. Twenty-seven families of macroinvertebrates were identified. They belonged to 6 orders of macroinvertebrates, Diptera with 86.82%, and had the highest frequency. Odonata (0.4%) had the lowest frequency. Canonical correlation analysis (CCA) indicates importance of nutrients in the distribution of different macroinvertebrates. Seventy-three percent of the variance in CCA was explained by nutrients and water temperature. Iranian Water Quality Index for Surface Water Resources Conventional (IRWQIsc) and Hilsenhoff Family-level Biotic Index (FBI), and biological monitoring working party/average score per taxon (BMWP/ASPT) consistently showed the same trend in our analyses. Our results showed high efficiency of water quality bio-evaluation for the river by measuring the macroinvertebrate communities, so that the results of the biological indices are consistent with the water quality index. Our method improves the costly, time-consuming and polluting methods that have been used in the past. Additionally, environmental changes due to a variety of land uses are better illustrated by our improved method. We conclude that FBI and BMWP/ASPT indices are suitable for assessing river health by macroinvertebrates.

Trophic strategies of the invasive Twospot livebearer (Pseudoxiphophorus bimaculatus, Teleostei: Poeciliidae) in a gradient of environmental quality in central Mexico

ABSTRACT Pseudoxiphophorus bimaculatus is an invasive species widely spread throughout freshwater ecosystems in central Mexico, for that reason we described its trophic strategy into a gradient of environmental quality. We sampled individuals of P. bimaculatus at eight sites located in the Lerma-Chapala and Pánuco River Basins during dry season. These basins have been impacted by industrialization and urbanization processes, but are considered as water reserves in México. To evaluate the environmental quality of the river, we applied the Visual-based Habitat Assessment, the Index of Biological Integrity and the Family-level Biotic Index. We assessed the trophic guild, the diet width, the omnivory level, and the diet selectivity. We also explored the relation of trophic strategies with the habitat condition. We captured a total of 202 individuals of P. bimaculatus from 10 to 67 mm of SL, finding a total of 24 food items. The diet of P. bimaculatus was composed of terrestrial, aquatic insects and bony fish. Pseudoxiphophorus bimaculatus in some sites can feed on different trophic levels, in other it is a specialist and secondary consumer. We found that P. bimaculatus changes its diet according the alterations in the habitat structure, water quality, and biotic integrity. Moreover, this invasive species can endure changes in the trophic web and food availability.

Baseline assessment of benthic macroinvertebrate community structure and ecological water quality in Rwenzori rivers (Albertine rift valley, Uganda) using biotic-index tools

The Rwenzori Mountains and Albertine Rift region of southwestern Uganda are part of a globally recognized biodiversity hotspot, but are currently facing pressures from intensified agriculture, mineral exploitation and hydroelectric power generation. This study was undertaken to assess the ecological water quality of Rwenzori rivers using biomonitoring metrics to determine the major factors shaping macroinvertebrate community structure in disturbed and undisturbed sites. We sampled macroinvertebrates at 66 sites along headwater tributaries and downstream areas of the Nyamwamba, Mubuku and Nyamugasani rivers, supplemented by five sites along the Kazinga channel and Lake George wetland, and identified a total of 32,579 macroinvertebrates to family level. Insecta was the most diverse taxon (45 families). Based on Average Score Per Taxon (ASPT) scores, sites were classified into four ecological water quality groups as excellent (40 sites), good (16), fair (7) and poor (8). Upstream sites had the highest abundance of pollution-sensitive families such as Caenidae and Hydropsychidae, while downstream sites had high numbers of Chironomidae. Lorenz curves revealed a low degree of evenness with Gini coefficient values ranging from 0.75 to 0.94. Ordination analysis revealed that total phosphorus, specific conductivity, chloride and chemical oxygen demand were key environmental variables contributing to variation among the sites. The majority of sites did show little to no anthropogenic influence with the exception of downstream sites. The results of this study provide useful baseline reference data, to assess and better manage the impacts of anthropogenic activities on the ecological integrity of the region’s aquatic systems. Furthermore, these datasets will advance the development of a regional family-level biotic index.

An assessment of pollution in aquatic environment using bioindicators: a review

This review highlights the importance of biological indicators in monitoring presence of pollution in aquatic environment. This assessment involves the use of living organisms (macro or microorganisms and plants or animals) as bioindicators of pollution in water bodies. These organisms are believed to show higher sensitivity to pollution than the best chemical indicators. Bioindicators or test of relevance to water study includes: test based on Chlorella vulgaris , Daphnia magna straus, test Spirotox , Microtox , using macroinvertebrates, algae and vertebrates (such as fishes). Variety of biotic indices based on macroinvertebrates community as indicators have been highlighted which includes: Microinvertebrate Biotic Index (MBI), Extended Trend Biotic index (ETBi), Belgian Biotic index (BBi), Rapid Bioassessment Protocols (RBPs), Biological Monitoring Water Quality (BMWQ) and Family level Biotic Index (FBI). Based on Microinvertebrate Biotic Index (MBI), grading of water quality alone with the taxonomic group of macroinvertebrate was divided into grade I, II, III, IV and V representing clean water, mildly, moderately, highly and severely polluted water with the tolerance rating of 2, 4, 6, 8 and 10 respectively. The review emphasized the need for the use of bioindicators in detecting water pollution, because bioindicators are much more sensitive than the best chemical indicators. Keywords: aquatic environment, bioassessment, bioindicators, pollutant, tolerance rating

Rapid Assessment of Water Quality in Teluk Lake by Using Macroinvertebrates (A Family Level Biotic Index)

In this study the water quality of Teluk Lake, Jambi Province by biological indices using macroobenthic during December 2017 to March 2018 were evaluated. Macro obenthic have been the most commonly indicator of running water quality to rapidly detect water quality changes. The methodology consisted on three stages: 1) macro invertebrates sampling and and sorting of the organisms in laboratory, 2) taxonomic identification of organisms and 3) determination and scoring with the Biological Monitoring Working Party -Average Score per Taxon (BMWP-ASPT) index. Result of water quality of Teluk Lake based on the diversity of macroinvertebrates was degraded with BMWP-ASPT index below 4. Based on the BMWP-ASPT score of the macroinvertebrates, both of sampling 1 and 2 were polluted with the category of medium and heavily polluted. In general, the decreasing of water quality of Teluk Lake was due to anthropogenic activities, so that the intolerant macro invertebrates could not survive in polluted waters while the tolerant ones can adapt well to the polluted aquatic environment.

Effect of Bahir Dar municipal effluents on water quality of the head of Blue Nile River

The study was conducted with the main objective of determining the effect of Bahir Dar municipal effluents on water quality of the head of Blue Nile River. Physico-chemical parameters were measured at seven points, whereas aquatic macro invertebrates were sampled at six sites. A total of 6813 aquatic macro-invertebrate individuals belonging to 30 families were collected. The Shannon–Wiener diversity Index, the Hilsenhoff family-level biotic index, Family richness and percent dipterans were calculated and differed significantly among sampling sites (p < 0.05). Physico-chemical parameter mean values differed significantly among sampling sites (p < 0.05), dissolved oxygen mean value being higher at sampling site (A) and BOD5, TDS and conductivity values being higher at (C5). BOD5, conductivity and total alkalinity mean values were above permissible levels set for municipal effluents to be discharged to surface water. DO, BOD5 and total alkalinity mean values at head of Blue Nile River were lower than WHO recommended values for drinking water. The study concludes that the Bahir Dar municipal effluents severely affected the water quality of the head of the Blue Nile River. Therefore, a municipal waste water treatment system is urgently recommended.Keywords: Bio-monitoring, macro invertebrates, physico-chemical parameters

Benthic diatom and macroinvertebrate assemblages, a key for evaluation of river health and pollution in the Shahrood River, Iran

The pre sent study analyzed the relationships of two different biological assemblages (diatom and macroinvertebrate) when they are used to characterize a set of stations (from reference stations to impacted stations) within the Shahrood River. In particular, we examined the issue of concordance among these assemblages and the physicochemical parameters detected, using both multivariate and multimetric methods. In addition, the trophic diatom index and Hilsenhoff family-level biotic index for macroinvertebrate assemblages were used to evaluate the ecological status of the Shahrood River. Diatom and macroinvertebrate assemblages in the Shahrood River differed significantly between reference and impacted stations. ANOSIM showed a significant difference in the composition and abundance of diatoms and macroinvertebrates among reference, influence and impact stations, especially between reference and impact stations. Results of CCA ordination showed that benthic diatoms and macroinvertebrate assemblages were mainly affected by DO, TSS, NO3−, PO43− concentrations and heavy metals such as Zn and Cd. Biotic indices for the Shahrood River suggested a water quality category of “fair” with fairly substantial organic pollution for the impacted stations. Finally, our results suggest that an appropriate management and restoration policy needs to be implemented for the Shahrood basin.

Effects of Bahir Dar Textile Factory Effluents on the Water Quality of the Head Waters of Blue Nile River, Ethiopia.

The study was conducted in 2013/14 with the objective of determining the effects of Bahir Dar textile factory effluents on the head of Blue Nile River water quality. Dissolve oxygen was higher at the upstream site of the river, whereas BOD5, TDS, and total alkalinity values were higher at wastewater outlet of the factory site. The mean values of dissolved oxygen, BOD5, and total alkalinity were above maximum permissible limits set by WHO for drinking water at head of Blue Nile River. The mean value of BOD5 was above permissible limit of IFC for textile effluents to be discharged to surface water. A total of 836 aquatic macroinvertebrate individuals belonging to 21 families were collected. The Shannon-Wiener Diversity Index, the Hilsenhoff family-level biotic index, family richness, and percent dipterans were calculated. Hilsenhoff family-level biotic index and percent dipterans metrics differed significantly among sampling sites (P < 0.05). Hilsenhoff family-level biotic index was higher at the most downstream site but percent dipterans were higher at site of discharge of effluent to the head of Blue Nile River. Therefore, there is indication that effluent demands frequent control and proper treatment before being discharged to the environment.

Benthic Macroinvertebrate and Chemical Assessment of Water Quality in Relation to the Shope Creek Trout Farm

Abstract North Carolina is the second largest commercial producer of rainbow trout, Oncorhynchus mykiss, in the United States, yet few studies have measured the effects of trout farm effluent on regional water bodies. Our objective was to assess water quality directly upstream and downstream of a low-production rainbow trout farm located on Shope Creek, a second-order stream in western North Carolina, using both biological and chemical assessment methods. Benthic macroinvertebrates were collected upstream and downstream of the trout farm annually from 2009 to 2011 using Hester-Dendy samplers. Organisms were identified to family and compared using the Family Level Biotic Index. We found no significant difference between mean upstream and downstream index values, suggesting no negative impacts of trout farm effluent on the macroinvertebrate community. Water samples were collected from each site on four days over a two month period, with three subsamples taken per site, per day. There were no significant differences between mean ammonia or phosphate levels upstream or downstream of the trout farm. While biochemical oxygen demand levels were significantly higher at the downstream site, this increase did not appear to affect the macroinvertebrate community. Between 2009 and 2011 the Shope Creek trout farm produced approximately 500 kg of fish annually. This is much lower than average annual regional trout farm production rates of 34,000 kg of fish, which likely accounts for the minimal impacts observed in this study.

English

A study was conducted to determine the downstream impact of Bahir Dar Tannery wastewater on the head of Blue Nile River using macroinvertebrates as bioindicators. Four sampling sites (one upstream and three downstream) were selected along the river and samples were collected from October to March, 2010/11. Macroinvertebrates were collected using standard dip net based on the Rapid Bioassessment Protocols for use in streams and wadeable rivers and identified to the family level. A total of 9,162 individuals belonging to 28 families were collected during the study period. Results of analysis of variance (ANOVA) showed that, there was significant difference in macroinvertebrate metrics among sampling sites. Percent Ephemeroptera Plecoptera Trichoptera (EPT) Index, Shannon Diversity Index and Benthic Macroinvertebrate Index were higher and percent Diptera, Chironomidae and Hilsenhoff Family level biotic index were lower at the reference site. The categorization of sites based on Benthic macroinvertebrate index value indicated that the site just below the effluent discharge and 200 m from it were severely to slightly, the last downstream site moderately to less and the reference or upstream site very little to none impacted. The water quality at these sites was also very poor to poor, fair to good and very good to excellent, respectively. The most impacted sites ranked last in all sensitive metrics while the reference ranked first in sensitive metrics indicating the severe impact of the effluent on downstream sites. The result gave the trends of pollution of the river by the effluent and the urgent need for measures to be taken. Key words: Tannery effluent, macroinvertebrates, bioindicators, Blue Nile River.

Spatial and seasonal variation in the macro-invertebrates and physico-chemical parameters of the Enfranz River, Lake Tana sub-basin (Ethiopia)

The main objective of the study was to assess the water quality of the Enfranz River by studying the distribution of macro-invertebrate taxa on the longitudinal gradient of the river. The macro-invertebrate community of the Enfranz River, located northwest of Bahir Dar city in the southern part of Lake Tana watershed, was studied to family taxonomic level in wet and dry seasons from August 2010 to May 2011. The river was sampled along its whole length at four sites from headwaters until its outflow in Lake Tana. A total of 15,286 macro-invertebrate individuals belonging to 35 families and 2 higher taxa were collected. The Shannon–Wiener diversity Index, the Hilsenhoff family-level biotic index, and three macro-invertebrate metrics were measured and related to five physico-chemical parameters. Macro-invertebrate diversity and biotic indices, and community metrics differed significantly among sampling sites (p<0.05), diversity being higher at the headwaters. Spearman's correlation coefficients showed that dissolved oxygen was significantly correlated with the macro-invertebrate diversity and biotic indices, and all three macro-invertebrate metrics (p<0.05). Diversity index, percent Ephemeroptera and percent Trichoptera were positively correlated to dissolved oxygen, whereas the biotic index and percent dipterans showed negative correlations. Furthermore, percent Ephemeroptera was negatively correlated with conductivity (p<0.05) and diversity was negatively related to total dissolved solids and conductivity. We conclude that downstream, the river is severely affected by land use of the people living along the river.

Water Quality Assessment of Sager Creek Utilizing Physiochemical Parameters and a Family-Level Biotic Index

An annual rapid bioassessment and physiochemical survey of Sager Creek in Northwest Arkansas was conducted. Sager Creek is a first to second order stream that flows through the city of Siloam Springs, AR. Invertebrate collections and water samples were collected at three different reaches, with the most downstream reach being below the effluent of the Siloam Springs Wastewater Treatment Plant. Benthic arthropods were collected, identified, and counted to produce a family-level biotic index and a family-level index of diversity. Statistical analysis revealed that these indices were significantly different for the effluent- influenced reach. However, this difference could not be correlated to any measured physiochemical parameter.

ارزیابی کیفی رودخانه سبزکوه در استان چهارمحال و بختیاری با استفاده از شاخص های زیستی کفزیان

هدف از این تحقیق بررسی تغییرات جمعیتی و گروه­های شاخص فون بنتیک و نیز طبقه ­بندی کیفی آب رودخانه سبزکوه می­باشد که تحت تاثیر مستقیم فعالیت چندین سایت پرورش قزل آلای رنگین­ کمان و تخلیه پساب­ های حاصله در مسیر مورد مطالعه بوده است. این بررسی به­ مدت یک­سال از آغاز دوره پرورشی کارگاه­ها در تیر ماه 1385، با انتخاب 7 ایستگاه که 4 مجتمع پرورش ماهی قزل آلای رنگین­ کمان را پوشش دادند، در یک مسافت 35 کیلومتری رودخانه سبزکوه واقع در استان چهارمحال و بختیاری انجام گردید. درشت بی­ مهره ­گان کفزی رودخانه به­ کمک یک دستگاه نمونه بردار سوربر به مساحت 1600 سانتیمتر مربع (40×40 سانتیمتر) جمع ­آوری و بررسی شد. در مدت بررسی کلا 34 گروه (خانواده و جنس) از درشت بی­ مهره ­گان کفزی شناسایی شدند که لارو حشرات آبزی بیش از 70 درصد از آنها را تشکیل می­دادند. مقادیر شاخص زیستی هیلسنهوف در ایستگاه­های مطالعاتی بین 3/9 (ایستگاه 1) و 5/5 (ایستگاه­های 4 و6) متغیر بوده است که بر اساس طبقه­ بندی هیلسنهوف نشانگر کیفیت آبی به ترتیب خیلی خوب و نسبتا خوب می­باشد. بر اساس ساختار جمعیت کفزیان و شاخص زیستی هیلسنهوف، کیفیت آب در ایستگاه­های پایین دست خروجی مزارع نسبت به ایستگاه­های بالادست و ورودی کیفیت پایین­ تری داشته­اند.

Use of Benthic Macroinvertebrate Indices to Assess Aquatic Health in a Mixed-Landuse Watershed

ABSTRACT Seven family-level metrics were determined from benthic macroinvertebrate samples collected monthly across four different landuse sites in the Cazenovia Creek watershed in western New York. We evaluated which metrics were most appropriate for, and effective in, discerning differences among the sites. Dramatic and consistent seasonal differences in metric scores were observed across all sites. All metric scores indicated markedly better biological health during winter months than during summer months. The biological impairment designation was highest in the summer at the suburban and agricultural sites. Coefficients of variation were considerably greater at the lower stream order sites. The metrics that were most appropriate and effective in assessing benthic assemblage health in this study were: richness, percent model affinity, family-level biotic index, and Ephemeroptera-Plecoptera-Trichoptera index. These indices correlated with a low amount of redundancy in a Pearson matrix, had significant discriminatory power in assessing biological impairments across sites, and had low variation within sites and seasons. This suggests these metrics should be selected for bioassessments in similar Great Lakes watersheds.

Assessment of environmental conditions of Nan-Shih stream in Taiwan

Abstract Restoration is a complex endeavor requiring the understanding of the degrading environment before applying any improvement measure. Environmental and ecological data in Nan-Shih stream were investigated in this study to assess its stream condition. Based on the data collected, the Index of Biotic Integrity (IBI index) which takes fish species as the major target, the Family-level Biotic Index (FBI) aquatic insects Hilsenhoff index and the Genus Index (GI) of algae were thus analyzed to quantify Nan-Shih stream's ecological system. The indices above were then applied on Index of Stream Condition (ISC index) to describe the overall river condition. Modified sub-indices, including the hydrology, physical form, streamside zone, water quality, and aquatic life, were made and used to provide baseline assessment information. ISC value is 33.89 evaluated as marginal level, in which hydrology sub-index score was the lowest indicating impact of artificial structures affecting flow significantly. The recommendations of the river corridor restoration and the habitat improvement were thus proposed as a reference for river management.

Rapid Assessment of Organic Pollution in a West-central Mexican River Using a Family-level Biotic Index

The cost-effectiveness of rapid assessment approaches make their adaptation for use in developing countries appealing, but biological assessment methods need to be validated before use in new geographic areas. The authors tested the suitability of a family-level biotic index for use in a river in west-central Mexico that receives organic point-source pollution from untreated municipal sewage and sugar-cane processing. The biotic index was highly correlated to dissolved oxygen, and could detect different levels of pollution. Information from rapid assessment biomonitoring was used successfully by local natural resource managers to help bring about improvements in water resource management.