Applying an index of biotic integrity based on fish assemblages in a West African river

A multivariate measure of river quality, the Index of Biotic Integrity (IBI), was adapted to a West African river, the Konkoure (Republic of Guinea). Fish assemblages were sampled using gill-nets during the dry season to provide data for the IBI. Ten metrics were subsequently defined. The capacity of the modified IBI to assess the impact of a bauxite treatment plant was tested. The IBI decreased as expected at the impacted station. Detailed examination of the data revealed that one family, the Mormyridae, was almost eliminated from the impacted station, suggesting that members of this familiy can be considered as intolerant species in future uses of the IBI in other African rivers.     

An index of biotic integrity based on fish assemblages for subtropical streams in southern Brazil

Several methods for calculating indices of biological integrity (IBIs) have been developed for different ecogeographic regions of the world. All of them calculate IBI scores by comparing against reference sites or historical data on fish assemblage composition. Because of intensive agriculture and urbanization in our study area, we located no reference sites, and historical information about fish assemblage composition did not exist. Instead, we developed hypothetical reference scores based on seasonal electrofishing surveys at six study sites in adjacent but geomorphologically different watersheds. Our IBI included 10 metrics that varied with degree of degradation. We found that Shannon–Wiener indices varied significantly between seasons, indicating significant changes in species composition. Therefore, we calculated seasonal IBI scores also, but these did not significantly differ from each streams general IBI score, which was calculated on the basis of four samples per site. General stream IBI scores reflected differing levels of anthropogenic disturbance.     

Development of a macrophyte-based index of biotic integrity for Minnesota lakes

Traditional approaches for managing aquatic resources have often failed to account for effects of anthropogenic disturbances on biota that are not directly reflected by chemical and physical proxies of environmental condition. The index of biotic integrity (IBI) is a potentially effective assessment method to integrate ecological, functional, and structural aspects of aquatic systems. A macrophyte-based IBI was developed for Minnesota lakes to assess the ability of aquatic plant communities to indicate environmental condition. The index was developed using quantitative point intercept vegetation surveys for 97 lakes that represent a range of limnological and watershed characteristics. We followed an approach similar to that used in Wisconsin to develop the aquatic macrophyte community index (AMCI). Regional adaptation of the AMCI required the identification of species representative of macrophyte communities in Minnesota. Metrics and scaling methods were also substantially modified to produce a more empirically robust index. Regression analyses indicated that IBI scores reflected statewide differences in lake trophic state (R² = 0.57, F = 130.3, df = 1, 95, p < 0.005), agricultural (R² = 0.51, F = 83.0, df = 1, 79, p < 0.005), urban (R² = 0.22, F = 23.0, df = 1, 79, p < 0.005), and forested land uses (R² = 0.51, F = 84.7, df = 1, 79, p < 0.005), and county population density (R² = 0.14, F = 16.6, df = 1, 95, p < 0.005). Variance partitioning analyses using multiple regression models indicated a unique response of the IBI to human-induced stress separate from a response to natural lake characteristics. The IBI was minimally affected by differences in sample point density as indicated by Monte Carlo analyses of reduced sampling effort. Our analysis indicates that a macrophyte IBI calibrated for Minnesota lakes could be useful for identifying differences in environmental condition attributed to human-induced stress gradients.     

Annual variations of biotic integrity in the upper Yangtze River using an adapted index of biotic integrity (IBI)

Adaptive modification and use of Karr's index of biotic integrity (IBI) for the upper Yangtze River, including 12 metrics in five categories, have typically occurred in line with the data collected by 6-year commercial fisheries investigation. These investigations were undertaken annually in four sections of the Upper Yangtze main channel between 1997 and 2002. These four monitoring sections (Yibin – YB, Hejiang – HJ, Mudong – MD, and Yichang – YC) were selected because they represent the part of the river that will be covering a 1000 km stretch that includes the future Three Gorges Reservoir (TGR), upstream of the Three Gorges Dam (TGD), an area influenced by the construction of TGD. In addition, historical data were used to show changes in the watershed by comparison with field investigations recently. The biotic integrity of the four sections were calculated and classified into different levels annually for recognizing its spatial and temporal variations. It was observed that IBI scores were becoming lower diminishingly since 1997 in all the four sections. Because all the data were collected before the impoundment of the Three Gorges Reservoir, it is obvious that human activities, especially over-fishing, must be crucial factor instead of damming in the upper Yangtze River in that period.     

Assessment of streams of the eastern United States using a periphyton index of biotic integrity

Benthic algae were collected from 272 eastern United States streams and rivers and analyzed for diatom species richness and dominance, the relative abundance of acidobiontic, eutraphentic, and motile diatoms, standing crops of chlorophyll and biomass, and alkaline phosphatase activity. These data were used to calculate a periphyton index of biotic integrity (PIBI), and values of the index were compared among reference, moderately impacted, and disturbed streams. The level of disturbance was based on stream chemistry, riparian disturbance, or a combined classification. Analyses of variance showed that PIBI was significantly higher in reference streams for all classifications. The PIBI and its metrics were correlated with many of the chemistry and habitat variables, and canonical correlation analysis revealed three significant environmental gradients which extracted 84% of the variance in the PIBI and its metrics. We used the mean 75th, 25th, and 5th percentile scores from the reference sites to set thresholds for excellent, good, fair, or poor condition. Applying these criteria to the cumulative distribution of total stream length in the region, we found that 4.3% of the stream length was in excellent condition; 20.8% in good condition; 56.4% in fair condition; and 18.5% in poor condition. The sensitivity of the PIBI and its component metrics to environmental stressors supports the use of this index for monitoring ecological conditions in streams in the eastern United States and as a tool to aid in diagnosing the causes of their impairment.     

Development of a preliminary index of biotic integrity (IBI) based on fish assemblages to assess ecosystem condition in the lakes of central Mexico

The lakes of central Mexico have great cultural, economic, and biological value, but they are being degraded at an accelerating rate. We employed historical data on fish communities from 19 of these lakes and case studies of community responses to environmental degradation from four of the best-studied, Xochimilco, Cuitzeo, Chapala, and Pátzcuaro, to construct a preliminary index of biotic integrity (IBI). This IBI was designed to be an easily applied method for assessing lake ecosystem health and evaluating restoration efforts. The IBI had 10 metrics: number of total native species, number of common native species, number of native Goodeidae species, number of native Chirostoma species, number of native sensitive species, percent of biomass as tolerant species, percent of biomass as exotic species, percent of biomass as native carnivorous species, maximum standard length of native species, and percent of exotic invertebrate parasite species on or in native fishes. Initial applications of the index showed promise, accurately ranking the relative degradation of the four case-study lakes. Further tests of the index are warranted, and more data are needed to standardize sampling procedures, improve species classifications, and refine metric scoring criteria.     

Validation of a fish-based index of biotic integrity for streams and rivers of central Mexico

An existing version of a fish assemblage-basedindex of biotic integrity (IBI) for the streamsand rivers of west central Mexico was testedwith independent data to validate itsusefulness as a measure of ecosystem qualityand to determine the geographic area where itis effective. Fish assemblages from 63 uplandsites in 10 basins in central Mexico(Armería, Ameca, Coahuayana, Marabasco,Purificación, Grande de Morelia, Grande deSantiago, Lerma, Balsas and Pánuco) wereassessed using the metrics and scoring criteriafrom the existing IBI and then compared withindependent evaluations of habitat and waterquality. IBI scores were congruent withhabitat and water quality values in theArmería, Purificación and Marabascobasins, where the IBI was first developed, aswell as in the adjacent Ameca and Coahuayanabasins. We conclude that the IBI can be usedwithout modification to assess environmentalquality in non-coastal streams and riverswithin these five basins. Further data areneeded from the Grande de Morelia, Grande deSantiago and middle Lerma basins, but ourresults suggest that the existing IBI may alsobe effective here. However, the existing IBIdoes not consistently reflect habitat and waterquality conditions in the Balsas and Pánucobasins and must be modified before it can beapplied there. Necessary modifications in theBalsas basin appear to be small and relatedprimarily to changes in the scoring criteriafor metrics. However, in the Pánuco basinmore substantive changes in the nature of themetrics are required. Changes in the IBI forthese basins are proposed. The IBI is nowvalidated for use in river monitoring,conservation and restoration efforts in 5basins in west central Mexico and suggestionsfor its application in other basins areavailable here.     

A fish-based biotic integrity index for assessment of lowland streams in southeastern Brazil

This study was carried out to develop and apply a fish-based biotic integrity index to assess lowland streams in a highly deforested region of the Upper Paraná River basin. Fifty-six first-order segments were randomly selected for environmental and fish evaluation. Because previous analysis had identified the main type of effect on the streams of the region as physical habitat degradation, 22 qualitatively biological attributes were selected and tested over a physical condition gradient between reference and degraded sites. Sensitivity and redundancy of each attribute revealed that five metrics were adequate for discriminating higher quality from degraded sites. Of the fifty-six streams assessed, one (2%) was classified as good, four (7%) as fair, ten (18%) as poor, and forty-one (73%) as very poor, indicating that, on a regional scale, many aspects of biological integrity are altered, indicative of serious degradation. Considering that first-order segments amount to 11,000 km in total, it is noticeable that 10,000 km of the stream segments have no more than half of the expected conditions, indicative of poor or very poor biotic integrity conditions. Possible strategies of mitigating this scenario are discussed. Handling editor: S. M. Thomaz     

A fish-based index of biotic integrity for upstream brooks in Flanders (Belgium)

From 1994 to 2000, 154 sites belonging to the grayling and trout zones were used to develop a fish-based multimetric Index of Biotic Integrity (IBI) as a tool to assess upstream brooks in Flanders (Belgium). All sites had a slope of at least 3‰ and a maximum width of 4.5 m. Fish assemblages were surveyed by electrofishing. From 28 candidate metrics 9 metrics were selected using ecological criteria and statistical analyses. The IBI was defined as the average of these 9 metrics after scoring them as 1, 3 or 5 by a modified trisection method and five integrity classes were defined to comply with the European Water Framework Directive (WFD). The IBI was tested internally by comparison with habitat quality scores at sites. A similar comparison was done using an independent set of data from sites of known ecological quality. Our IBI clearly distinguished good sites from disturbed sites and heavily disturbed sites from moderately disturbed sites, thereby meeting the criteria imposed by the WFD.     

The fuzzy index of ecosystem integrity (FINE): a new index of environmental integrity for transitional ecosystems

The European Water Framework Directive (WFD) (2000/60/EC) requires assessing the ecological quality status of water bodies, and gives great importance to the biological components of the ecosystem. Within this framework, a multimetric, fuzzy-based index for the evaluation of environmental quality (FINE: fuzzy index of ecosystem integrity) has been developed using data from several Italian coastal lagoons, gathered with seasonal frequency at diverse sites in each lagoon. The rationale of FINE is that certain attributes, selected on the basis of established principles of benthic ecology, are fundamental for lagoon ecosystem function. FINE is composed of seven ecosystem attributes (variables) each of which have ecological relevance for lagoon ecosystems. Individually, all these attributes are themselves useful indices of environmental conditions. However, the combination of these attributes into a single fuzzy index, provides a more robust, overall index of the response of the natural communities to environmental perturbations and avoids misleading or ambiguous results. Each variable is not represented by a single numerical value, but by several categories that describe its properties: in the present model we considered a total of seven variables: two with four modalities (low–medium–high–very high), one with three (low–medium–high) and three with two (low–high), plus a qualitative variable (yes–no), that altogether generate 768 rules. FINE is a low-cost, flexible and robust routine index of lagoon ecosystem impairment and could be of particular benefit to environmental managers and policymakers who require tools capable of expressing the degree of degradation or environmental quality of different lagoon habitats. For its relative simplicity in the application, FINE could be a good candidate to assess the environmental quality of Mediterranean transitional ecosystems. Guest editors: A. Razinkovas, Z. R. Gasiūnaitė, J. M. Zaldivar & P. Viaroli European Lagoons and their Watersheds: Function and Biodiversity     

Development,calibration, and validation of a littoral zone plant index of biotic integrity (PIBI) for lacustrine wetlands

We examine lacustrine wetland plant assemblages in the Central Corn Belt Plain portion of the Lake Michigan basin and developed a multimetric plant index of biotic integrity (PIBI). Our objectives were to determine the structural and functional attributes of littoral zone plant assemblages of least-impacted lacustrine wetlands, establish and test candidate metrics, statistically test and calibrate metrics, and finally validate a PIBI along a disturbance gradient. Of 35 candidate metrics, we chose 11 metrics that were grouped into four categories: species richness and composition, species tolerance, guild structure, and vegetation abundance. Based on Spearman correlations, we identified a suite of metrics, particularly those related to species richness and tolerance that had a strong response to human-induced habitat change. The overall PIBI correlated strongly with independent measures of habitat quality (p < 0.001) using a qualitative habitat index developed for lacustrine habitats. We validated the lacustrine PIBI by comparing index response to various landuse, landcover, and management types. Least impacted lakes and lakes classified as recreational or undergoing ecological restoration were not statistically separable and received the highest index scores, while the lowest scores were associated with industrial and residential land use. Least-impacted sites differ significantly (p < 0.001) from both industrial and residential lakes.     

The biotic resistance role of fish predation in fouling communities

Predation may often influence native species dynamics and so may be important for the control of introduced species as well. Here, we examine how predation can regulate fouling communities on artificial substrates in the coast of Brazil. Specifically, we tested whether predators limit colonization and establishment of introduced species. A predation experiment using plastic plates as experimental replicates (predator excluded and not excluded) was carried out in Ceará, Bahia, São Paulo and Santa Catarina, between 3°S and 27°S. Ninety-eight species colonized the plates, 14 of which were introduced. While species richness was similar among the treatments (except in Santa Catarina), community structure varied by treatment and introduced species were less abundant in the predation treatment at all sites. Also, predation was selective and controlled introduced, poorly defended, species, specifically ascidians. Thus, biotic resistance driven by predation was not ubiquitous but apparently targets one group of major economic and environmental impact. As a consequence, introduced barnacles were released from competition with dominant ascidians and thus the ecosystem service (biotic resistance) performed by fish alone was unable to completely avoid or control the introduction of non-native species. Control measures must rely on various approaches, but if we want fish to contribute in this control, it is very important to conserve the local native assembly of predators in order to reap their benefits in this ecosystem service.     

Ecological integrity of supraspecific taxa and the arctic biota

Some specific features of the development of concepts about integrity (systemic organization) of supraspecific taxa are considered. Several forms of integrity can be distinguished: taxonomic, or genealogical; evolutionary (considering a taxon as a developing system); ecological, or eco-adaptive (manifestation of the properties of a united system in the course of exploring the various conditions and types of environment by the phyletically specified biota). Taxa of different level “behave” as whole units or blocks, forming structural parts of the cenotic and biotic forms of life. The properties of integrity, systemic organization of supraspecific taxa can be displayed by analysis of changes in the structural parameters of the biota related to latitudinal gradients of climatic factors, in phenomena of individualistic distribution, ecological substitution (vicariance) of taxa, and preservation of their ecological functions (adaptive zone) despite the reduced species diversity. The variants of adaptive exploration of high-latitude landscape-zonal conditions are considered using examples from the Arctic flora and fauna.     

广西河池地区河流基于鱼类的生物完整性指数筛选及其环境质量评估

为促进生物完整性评价法在中国的应用,加强珠江上游广西河池地区河流环境质量监测,该研究以鱼类为研究对象,初步构建了包含21个指标在内的广西河池地区河流基于鱼类的生物完整性评价的指标体系。根据鱼类调查所收集数据,结合历史资料的记录,对这些指标进行筛选和赋值,最终确立了6个指标,用于建立适合广西河池地区河流的基于鱼类的生物完整性指标体系;应用此指标体系对该地区部分河流(河段)进行了评价。评价的结果表明,小环江鱼类完整性为好;红水河、龙江和大环江为一般;刁江为极差。评价的结果与河流受人为干扰的实际情况相吻合,研究构建的评价体系可供河池周边地区使用和借鉴。生物完整性评价是水域环境质量监测的重要手段,为使生物完整性评价更加科学和客观,应加强生物完整性与环境因子之间关系的研究。     

Primary nutrients and the biotic integrity of rivers and streams

1. Controls to reduce loadings of primary nutrients to maintain biotic integrity in rivers and streams have not been widely implemented because the relation between nutrients and chlorophyll, and its consequences for higher trophic levels, is confounded in lotic ecosystems by their openness, the variable degree of nutrient limitation and by the effect of physical factors.
2. The relationship between primary nutrients and biotic integrity in rivers and streams was tested using biological, physical and chemical information collected since 1982 from similar locations in streams throughout Ohio using standard procedures.
3. There was a negative correlation between nutrients, especially total phosphorus, and biotic integrity. The deleterious effect of increasing nutrient concentration on fish communities in low order streams was detectable when nutrient concentrations exceeded background conditions (total inorganic nitrogen and phosphorus > 0.61 mg L^–1 and 0.06 mg L^–1, respectively).
4. These results suggest that the control of release of toxins and oxygen‐demanding wastes to rivers is insufficient to protect aquatic life, and confirm the importance of non‐point sources of pollution in catchment planning as well as the combined effect of habitat and riparian quality on nutrient assimilation.     

The coral core microbiome identifies rare bacterial taxa as ubiquitous endosymbionts

Despite being one of the simplest metazoans, corals harbor some of the most highly diverse and abundant microbial communities. Differentiating core, symbiotic bacteria from this diverse host-associated consortium is essential for characterizing the functional contributions of bacteria but has not been possible yet. Here we characterize the coral core microbiome and demonstrate clear phylogenetic and functional divisions between the micro-scale, niche habitats within the coral host. In doing so, we discover seven distinct bacterial phylotypes that are universal to the core microbiome of coral species, separated by thousands of kilometres of oceans. The two most abundant phylotypes are co-localized specifically with the corals'' endosymbiotic algae and symbiont-containing host cells. These bacterial symbioses likely facilitate the success of the dinoflagellate endosymbiosis with corals in diverse environmental regimes.     

Determining the influence of habitat and chemical factors on instream biotic integrity for a Southern Ohio watershed

The relative influences of water quality and in-streamhabitat on receiving water biology were investigatedin the Little Miami River, Ohio, a national and statescenic river located in the southwest corner of thestate. Monitored sample data for water chemistry,habitat, invertebrates and fish were obtained fromfederal and state sources and integrated via ageographical information system (GIS), using a uniquestream segmenting system. Locations and flowinformation for municipal wastewater treatment plants(WWTPs) were also integrated into the system. Therelative importance of water chemistry and habitat onbiological sample information was determined usingmultivariate forward stepwise regression. Theprincipal environmental factors that influencedbiological responses were in-stream habitat andpercent cumulative WWTP effluent at mean flow. Cumulative WWTP effluent at low flow dilution,nutrients and total toxic units from metals andammonia did not correlate with biological responses(e.g. number of mayfly species, invertebrate communityindex (ICI), number of fish species and index ofbiotic integrity (IBI)). We found the GIS-based datamethods to be highly useful for understanding theprincipal processes that guide receiving water health.