Index Of Biotic Integrity Research Articles

Assessment of Biotic Integrity of the Coastal Freshwater Tidal Zone of a Temperate Estuary of South America through Multiple Indicators

The aim of this study was to propose an index [Index of Biotic Integrity for the Río de la Plata (IBIRP)] formulated from a minimum of information-rich metrics related to biological integrity for evaluation of the coastal freshwater tidal zone of the Río de la Plata estuary. A total of 23 sites were selected along 170 km of shoreline (34°27′10″ S, 58°30′21″ W and 35°23′28″ S, 57°08′50″ W), being influenced by different land uses. We explored 36 biotic descriptors (designated candidate metrics), each of which is considered as an environmental indicator, and selected four metrics: two related to phytoplankton assemblage (planktonic cyanobacterial density and phytoplanktonic total density) and two linked to benthic assemblages, the diatoms (percent most tolerant taxa), and the invertebrates (percent Tanaidacea). The metrics that were chosen to integrate the IBIRP provide valuable information about the biotic integrity both in terms of time and space. The multimetric index can assume values between 0 (very bad status) and 10 (very good status). The IBIRP correlated significantly with the second (p < 0.001) and fourth (p < 0.01) factors of the factor analysis—those being related to variables indicative of eutrophication and organic pollution. This index constitutes an approach that is capable of reflecting the anthropogenic impacts produced along the coast of the Río de la Plata, with the inherent flexibility of being subject to modification and ultimate validation for estuaries of similar characteristics.

The response of the young of the year fish to river obstacles: Functional and numerical linkages between dams, weirs, fish habitat guilds and biotic integrity across large spatial scale

River obstacles are recognised as being among the serious ecological concerns, having negative effects on biodiversity and ecosystem functions. They have been shown to affect fish community structure, which represents a fundamental component of the biological integrity of riverine ecosystems. However, a general quantitative relationship that links the response of fish community structure to river obstacles across larger spatial scales is lacking. We assessed young of the year (YOY) fish (27,596 specimens and 35 species) from a total of 54 study sites distributed across three international river basins. The YOY fish community structure was expressed as the probability of habitat-related guild dominance. We also examined the indicative value and responsiveness of two large spatial-scale, fish-based indices of biological integrity (IBI), the European Fish Index (EFI) and the Czech multi-metric index (CZI). We analysed two types of obstacles (1118 weirs and 28 dams for a total of 2126 obstacles) for which numerical and distance-related descriptors were derived using a geographic information system (GIS). All the obstacles considered together were found to be the most relevant predictor of YOY fish community structure response. The negative impact on YOY fish (a loss of rheophilic species and low IBIs values) increased with the increasing number of obstacles and the decreasing relative distance between two consecutive obstacles, indicating the habitat quality and availability and the poor connectivity of particular watersheds. This investigation allowed us to identify the functional and numerical responses of the YOY fish community structure to river obstacles across hydrological networks. Our results contribute an important prerequisite to river restoration efforts, identifying where in the hydrological networks either ecological studies or restoration actions would produce the most effective results.

Using a process‐based catchment‐scale model for enhancing field‐based stream assessments and predicting stream fish assemblages

ABSTRACT Catchment‐modelling techniques, although not yet widely used in biological contexts, may be a valuable tool in the management and conservation of stream fishes. This study was undertaken to evaluate the potential of a catchment‐scale hydrologic model, the Soil and Water Assessment Tool (SWAT), to explain characteristics of stream fish assemblages and to enhance current field‐based stream assessments. Stream fish assemblages, instream habitat, geomorphology, and water quality were surveyed in 16 study catchments in Ohio, USA. Subsequently, SWAT was used to model stream discharge, sediment flux and concentration, and nitrogen and phosphorus yields for each catchment. Principal component analysis (PCA) and multiple linear regression were used to explore potential relationships between environmental factors (both reach‐level measurements and SWAT‐modelled catchment‐scale processes) and fish assemblage descriptors assessed within the framework of an Ohio fish‐based Index of Biotic Integrity (IBI). Reach‐level factors contributed to three of the four significant regression models, explaining 12% to 14% of the variation in fish species richness, the number of darter (Etheostoma) species, and the number of sensitive/intolerant species. SWAT‐modelled parameters including minimum and mean annual flow and sediment yields explained significant variation in total IBI scores (57%), species richness (63%), the number of darter species (60%), and the number of sensitive/intolerant species (61%). The results support the utility of SWAT as a complement to field‐based surveys. It is proposed that process‐based catchment‐modelling techniques such as SWAT could improve stream fish management and conservation efforts when used as a screening tool to target streams and catchments for subsequent field surveys and as a method to model potential impacts to stream ecosystems and fish assemblages in highly sensitive areas and/or inaccessible catchments. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Relationships between the Seasonal Variations of Macroinvertebrates, and Land Uses for Biomonitoring in the Xitiaoxi River Watershed, China

AbstractThe impacts of differences in watershed land uses, and differences in seasonality on benthic macroinvertebrate communities, were evaluated in 12 stream sites within the Xitiaoxi River watershed, China, from April 2009 to January 2010. The composition of macroinvertebrate community differed significantly among three land use types. Forested sites were characterized by high taxa richness, diversity and the benthic‐index of biotic integrity (B‐IBI), while farmland and urban disturbed stream sites presented contrary patterns. The percentage of urban land use, conductivity, dissolved oxygen, ammonia nitrogen and total phosphorus were the major drivers for the variations. The land use related water quality stress gradients of the four sampling seasons were determined by means of four independent Principal Component Analyses. The responses of macroinvertebrate community metrics, to anthropogenic stressors, were explored using Spearman Rank Correlation analyses. All the selected metrics, including total numbers of taxa, numbers of Ephemeroptera, Plecoptera and Trichoptera taxa, percentage of non‐insect abundance, percentage of scrapers abundance, Pielou’s evenness index, Simpson diversity index, and the Benthic Index of Biotic Integrity were correlated significantly with environmental gradients (PC1) in autumn. In other seasons such correlations were less pronounced. Our results imply that autumn is the optimal time to sample macroinvertebrate communities, and to conduct water quality biomonitoring in this subtropical watershed. (© 2012 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Assessing the effects of sewage effluents in a Mediterranean creek: fish population features and biotic indices

Sewage effluents are one of the main anthropogenic stressors in Mediterranean rivers. The establishment of a cause–effect relationship is hindered in natural systems by the existence of confounding factors (i.e. biotic interactions). Here we analysed the effects that anthropogenic stressors have on a mono-specific fish community (Iberian redfin barbel population, Barbus haasi) inhabiting the northern edge of its distribution range. In Spring 2004, a total of 40 consecutive sampling sites were surveyed in Vallvidrera creek, and 1,331 specimens were measured and weighed. A principal component analysis was performed to synthesize the information provided by 22 environmental variables. Analysis of variance, bivariate correlation analyses and multiple linear regressions were then used to determine the influence of the environmental gradients built (water quality, hydromorphology, woods and macrophytes, and degree of silting) on fish population features (fish size, body condition status, density and biomass). The findings revealed that water quality was the most significant environmental gradient for this fish population. In particular, fish density decreases and fish length increases in those sites exposed to sewage. Additionally, our results showed the best body condition of those specimens inhabiting fast flow reaches which confirms the rheophilous condition of B. haasi. However, these findings were unnoticed for the current version of the index of biotic integrity using fish as bioindicators in Catalonia. Resource managers need to refine diagnostic tools in order to detect subtle deleterious changes on fish communities before they become evident at population scale. Conservation measures should be focused in these small streams in where the best preserved native fish populations usually inhabit. This study suggests the need to change water management policies in Mediterranean rivers to improve the water quality of sewage effluents and increase the dilution power of these rivers.

Development of a Macroinvertebrate - based Index of Biotic Integrity (M-IBI) for Colombo-Sri Jayawardhanapura Canal System (A new approach to assess stream/ wetland health)

Macroinvertebrates have been identified as excellent indicators of stream (wetland) health as they respond rapidly to environmental changers and provide short to medium term pollution history records. Current study was aimed to develop a Macroinvertebrate-based Index of Biotic Integrity (M-IBI) to monitor stream health of Colombo-Sri Jayawardhanapura canal system. Macroinvertebrates were sampled using a D-framed kick net from ten stations during the period of Nov 2008 to June 2009. Habitat characteristics and some water quality parameters also recorded. For the index development, those ten stations were grouped into two as ’Reference’ and ‘Degraded’ based on their habitat characteristics and some water quality parameters. Then 41vcandidate metrics were nominated for statistical analysis process. After considering their sensitivity to stream impairment, ability of showing exceptionally strong discrimination between reference and degraded sites and less redundancy, ten candidate metrics were selected for M-IBI development. Validity of the index was tested with a new independent data set. Scores acquired for these data set were positively correlated with DO values (r = 0.578). That concluded the potential of using M-IBI developed for biological monitoring and improving biotic integrity of streams and wetlands.

Development and validation of two fish-based indices of biotic integrity for assessing perennial coolwater streams in Wisconsin, USA

Perennial coolwater streams (maximum daily mean water temperature 20.7–24.6°C; 90th percentile annual exceedence flow≥0.0283m3/s) are common in the Laurentian Great Lakes region of North America, including the state of Wisconsin, but they lack specific and effective bioassessment tools. I used landscape-scale ecological modeling of geographically referenced data on stream location, stream and valley slope, watershed surficial geology, air temperatures, riparian and watershed land cover, watershed road and population densities, and watershed nutrient and wastewater inputs to classify Wisconsin stream sites based on water temperature, flow, and degree of environmental degradation. Fish data from sites classified as perennial coolwater were then analyzed with objective standardized procedures to develop coolwater indices of biotic integrity (IBI). Because of substantial differences in their fish assemblages, separate IBI's were formulated for cool-cold transition (20.7–22.5°C) and cool–warm transition (22.6–24.6°C) streams. The cool–cold transition IBI had five metrics: numbers of darter, madtom, and sculpin species, of coolwater species, and of intolerant species, and the percentages of individuals as tolerant species and as generalist feeders. Scoring criteria differed between northern and southern Wisconsin (boundary at 44.6°N latitude) for the coolwater species metric. The cool–warm transition IBI also had five metrics: numbers of native minnow, of intolerant, and of benthic invertivore species, and percentages of individuals as tolerant species and as omnivores. Scoring criteria differed between small and large streams (boundary at 200km2 watershed area) for the intolerant species, benthic invertivore species, and percentage tolerants metrics. In validation tests, scores for both IBI's were significantly related to independent measures of human disturbance, indicating that the IBI's would be useful tools for assessing the environmental quality of coolwater streams. However, for any given level of human disturbance, scores for both IBI's varied substantially, suggesting that multiple IBI samples from multiple sites would be needed to provide a reliable evaluation of a particular stream segment.

Short-term changes in-stream macroinvertebrate communities following a severe fire in the Lake Tahoe basin, California

Large and severe wildfires can dramatically alter terrestrial and aquatic ecosystems. We documented changes in benthic macroinvertebrate communities and physical habitat at two sites along Angora Creek, CA, USA for 2 years following a severe fire. Although post-fire years had low precipitation, canopy cover and bank stability declined dramatically following the wildfire (canopy cover: 88% pre-fire, 22% post-fire; stable bank: 93% pre-fire, 11% post-fire). Substrate also changed substantially, with fine sediment 8× more abundant post-fire and cobble 7× less abundant post-fire. We found no consistent changes in taxonomic richness or diversity following the fire, but post-fire densities and percentage of sensitive taxa were significantly reduced. We observed large reductions in relative abundances of shredder and scraper taxa, while collector-gatherer abundances increased. Community composition shifted away from pre-fire configurations, and continued to diverge in the second year following the fire. Scores from a regionally derived index of biotic integrity (IBI) were variable but overall much lower in post-fire samples and did not show recovery after 2 years. Overall, our study demonstrated substantial post-fire effects to aquatic ecosystems even in the absence of large flooding or scouring events, and showed that these effects can be transmitted downstream into unburned reaches.

MULTIVARIATE STATISTICAL ANALYSIS OF AVIAN INDEX OF BIOTIC INTEGRITY

The Index of Biotic Integrity (IBI) is a multi-metric index designed to measure the changes in ecological and environmental conditions as affected by human disturbances. Hence, IBI is used in practice to detect divergence from biological integrity attributable to human actions. The incorporation of biological attributes is often done at both the individual and higher level assemblages. The objective of this paper is to demonstrate the construction and statistical evaluation of a multi-metric Avian Index of Biotic Integrity (A-IBI). Canonical correlation analyses are utilized to select pertinent avian metrics as impacted by vegetation and hydrology variables. The resulting avian metrics are then ranked, according to a pre-specified scale of human disturbance, and the A-IBI scores are subsequently computed. The multivariate models as well as the final A-IBI scores are statistically validated, both spatially and temporally, using independent data sets. The techniques are demonstrated using five years of avian survey conducted on the terrestrial environments of the Kootenai River watershed in Northern Idaho and Northwestern Montana.

Application of multiple index development approaches to benthic invertebrate data from the Virginian Biogeographic Province, USA

Previous work had indicated that the Virginian Province Index did not perform well in a smaller estuarine complex. While it was hoped that the existing Chesapeake Bay Benthic Index of Biotic Integrity, with its greater number of metrics and habitat separation would be more adaptable, this index also did not perform well outside of Chesapeake Bay. In this study we assembled additional metrics and applied different methods of index compilation to explore the indices relative strengths and weaknesses. Three different approaches were utilized – two multimetric indices (Chesapeake Bay IBI and the Mebane IBI) and a statistical logistic regression technique. The data were subdivided by habitat (salinity and grain size), and indices compiled using the same initial group of benthic metrics. Each approach was examined for its classification accuracy for both reference and impaired sites for the entire Virginian Province. The Chesapeake Bay IBI approach did not perform well in this study. In contrast, another multimetric approach, the Mebane IBI approach, performed well, as did the statistical logistic regression approach. Both techniques have promise for index development and could be useful in applying a biological condition gradient to estuaries.

Revisiting ecological integrity 30 years later: non‐native species and the misdiagnosis of freshwater ecosystem health

AbstractAssessing the ecological integrity of freshwater ecosystems has become a priority to protect the threatened biodiversity they hold and secure future accessibility to the services they provide. Some of the most widespread applications of biological indicators are fish‐based indices. These have mostly mirrored the approach proposed by Karr 30 years ago (Index of Biotic Integrity; IBI), based on the comparison of observed and expected composition and structure of local fish assemblages in the absence of major perturbations, using the so‐called reference condition approach. Despite the notable success of the implementation of fish‐based indices, most of them overlook non‐native species as a source of ecosystem degradation, and evaluations are focused on the physico‐chemical condition of freshwater ecosystems and their effects on freshwater biodiversity. Almost 90% of 83 reviewed IBIs did not consider non‐native species when defining reference conditions. Most IBIs used non‐native species in conjunction with native ones to construct the metrics that conform to the index. The response of the IBI to the effect of non‐native species has hardly ever been tested. When developing and evaluating IBIs, attention was mostly directed to ensuring the correct response of the index to physico‐chemical parameters, which could otherwise be characterized more effectively using alternative methods. Current application of IBIs entails a misuse of biological indicators by overlooking some types of degradation that cannot be otherwise evaluated by traditional methods. This constrains the capacity to adequately respond to one of the most challenging and common threats to the conservation of freshwater fish diversity.

Development of a submerged aquatic vegetation community index of biotic integrity for use in Lake Ontario coastal wetlands

Submerged aquatic vegetation (SAV) supports biodiversity in the Great Lakes basin by providing an important source of food and habitat for breeding marsh birds and fish and it is desirable to have indices enabling reporting on the condition of SAV, to complement already available indices for the condition of fish, aquatic macroinvertebrate, and bird communities and water quality. We developed a SAV index of biotic integrity (SAV IBI) with 6years of quadrat-based vegetation species composition data (2003, 2005–2009) collected across 46 coastal wetlands on the Canadian side of Lake Ontario. We evaluated the suitability of thirteen potential metrics that described species richness, floristic quality, and cover. Metrics with a significant linear or non-linear response to disturbance (as assessed by a water quality index; WQI) were retained for use in the SAV IBI. Retained metrics included turbidity-intolerant species richness, native species richness, coefficient of conservatism, and total cumulative coverage. Lower SAV IBI scores indicated poorer coastal wetland conditions. Coastal wetlands in poor condition were located in more urbanized watersheds (e.g., Durham Region) relative to wetlands in more natural watersheds. Fish and breeding bird community condition showed strong significant relationships with the SAV IBI, suggesting that SAV was an important component of fish and bird biodiversity. Our SAV assessment index and its relationship to faunal diversity can be used to inform conservation decisions.

Use of single versus multiple biotic communities as indicators of biological integrity in northern prairie wetlands

As much as 70% of prairie wetlands in Canada have been lost. Although further degradation of natural wetlands is considered to be somewhat offset by wetland construction and restoration, Canada lacks bioassessment tools that can track ecosystem health in prairie wetlands. Indices of biological integrity (IBIs) use one or more biotic communities to compare the biological condition of a particular site to conditions found in least-impacted reference sites. Using the IBI approach, we evaluated the potential of 5 biotic communities to assess wetland health in northern prairie wetlands in Canada. Vegetation in the wet meadow, emergent and open-water zones as well as wetland-dependent songbirds and waterbirds were sampled at 81 semi-permanent/permanent natural and compensation wetlands spanning an environmental stress gradient. Metrics with strong linear relationships to the stress gradient (R2>0.2) were combined into an IBI for each biotic community and were subsequently validated at a suite of test sites. After validation, the entire data set was combined and each IBI was evaluated based on its linear relationship to environmental stress. Wet meadow zone vegetation was a strong indicator of environmental stress (R2=0.68, p<0.001), as was the wetland-dependent songbird community (R2=0.59, p<0.001). The emergent zone vegetation community was a relatively weak and inconsistent indicator of environmental stress, while the open-water zone vegetation and waterbird communities were poor indicators. To evaluate whether monitoring more than one biotic community provided additional information about a site's biological and environmental condition, we produced a two-taxon IBI that combined wet meadow zone vegetation and wetland-dependent songbird metrics. The two-taxon IBI had a marginally stronger linear relationship to the stress gradient (R2=0.72, p<0.001) than any single biotic community alone, although we argue that this added information would not warrant the extra cost, effort, and logistical barriers of sampling both plants and birds. The wet meadow zone vegetation and wetland-dependent songbird IBIs were strong surrogates of one another (R2=0.57), suggesting that wet meadow zone vegetation can be used to predict the health of wetland-dependent songbirds, and visa versa. Our results suggest that habitat for healthy wet meadow zone vegetation and wetland-dependent songbird communities is being degraded as compensation sites are replacing their natural analogs.

Long-term change in the biotic integrity of a shallow tropical lake: A decadal analysis of the Lake Chapala fish community

We describe the successful application of a 4-decade analysis of an Index of Biotic Integrity (IBI) demonstrating its assessment value when applied to the fish community of Lake Chapala. We based our analysis on fish community and fishery composition and on the proportion and density of native and exotic species for each decade. Fisheries landings and IBI values document a long-term downward trend since the 1970s. Data from the 1990s and 2000s reveal a dramatic drop in the IBI score to 20 points (out of a possible 100), a rating of very poor. The fisheries collapse and the loss of 11 native species as a consequence of habitat degradation and invasive species have reduced native fish biomass and richness. Fluctuations in rainfall, principally, and water-extraction related to human activities have had a major impact on the lake. Additionally, water quality deterioration has been caused by a lack of wastewater treatment. The fish community has been further modified by large increases in the number and biomass of exotic fishes. Although the exact degree of decline in biotic integrity is impossible to determine because of uncertainty about the representativeness and accuracy of some historical information, the analysis of the temporal changes in the IBI provides compelling evidence for an accelerating drop in ecosystem health. The application of IBI, which is broad in scope and has flexible data requirements, can serve as a template for assessing trends in other water bodies with a history of fisheries data but limited standardized monitoring of the fish community.

Effect of previous use and processing technique on performance of multiplate Hester–Dendy samplers

We evaluated macroinvertebrate-based metrics from Hester–Dendy samplers (HDs) that were either new or previously deployed (HS status) and were processed with either picking or scraping methods. The metrics assessed included the total number of individuals, the number of intolerant individuals, the total number of families, and the number of Ephemeroptera, Plecoptera, Trichoptera (EPT) individuals. No significant differences in mean number of individuals, intolerant individuals, and total families were detected between processing techniques or HD status (all p > 0.05). Mean number of EPT individuals did not differ between processing methods (p > 0.05), but previously deployed HDs yielded significantly more EPT individuals than new HDs (p = 0.001). The EPT data are of particular interest because these organisms are important components of indices of biotic integrity and are used to assess water-quality status. Previously deployed and new HDs should not be used in the same study because colonization by EPT organisms differs between them.

Macrophyte Species Distribution, Indices of Biotic Integrity, and Sampling Intensity in Isolated Florida Marshes

This study examined the distribution of wetland plants used in macrophyte-based index of biotic integrity (IBI) metrics to determine the effectiveness of zone sampling in assessing wetland condition. Using sampling data from a previous study of 74 emergent isolated wetlands, macrophyte taxonomic data and resulting IBI metrics were analyzed for various wetland zones and compared against the original site metrics. Zones were defined by parsing each sampling transect (from wetland edge to center) into thirds—creating an outer, intermediate, and inner zone—and constructing two additional zones representing two-thirds of the original sampling area—an outer plus intermediate zone and an intermediate plus inner zone. While a highly-significant decrease in mean species richness was observed from the wetland exterior to interior, there were no significant differences between metric values derived from site data and those derived from zone data. Linear correlations between metrics from the outer zone and site data were highly significant (R 2 > 0.94), but linear correlation strength decreased with the intermediate and inner zones, respectively. Thus, macrophyte-based indicators of biological integrity can be efficiently assessed by sampling the outer third of a wetland—a 66% reduction in the area and effort required to monitor isolated wetland condition.

Perspectives from the French workshop on the development and validation of biomarkers and bioassays for the monitoring of aquatic environments

During the past three decades, there has been an increasing interest in the field of ecotoxicology for development of effect-based monitoring tools (EBMTs) including in vitro tests, biomarkers and whole organism bioassays. This interest is due to the practical application of EBMTs in the surveillance of the quality of water and aquatic ecosystems (ICES, 2008). Within this framework, these ecotoxicological tools seem to offer numerous potential advantages, as they allow one to take into account the cumulative impact of the whole contaminants present in the field, and the bio-available and active fractions of toxicants as well as their degradation bioaccumulation, biotransformation (Lam and Gray, 2003; Hecker and Hollert, 2009). Hence, they are often seen as complementary tools to conventional environmental monitoring approaches, mostly based on the measurement of a predefined list of chemical substances in various aquatic compartments (water, sediments and biota) and the analyses of indices of biological integrity (OSPAR 2004). Due to these research activities, several core EBMTs (SGIMC, 2011) are now well characterised and may be directly used to assess the quality of the aquatic environment under a European consensus (Table 1; Sanchez and Porcher, 2009; Lyons et al., 2010). However, if EBMTs are widely used in research studies and provide, at geographically and temporally limited scales, data on ecotoxicological status of water bodies, few applications of EBMTs are currently implemented in regulatory environmental monitoring programs.

Ecological effect, Monitoring and Warning of Water Pollution in Drainage Basin*

Based on the watershed ecosystem structure and function,the ecological effects(structural and functional effects) caused by water pollution were described,respectively,and the features of biological,ecological monitoring and warning were also summarized.Ecological monitoring was developed by traditional and simple index(ratio of sensitive and tolerance species),one single index(community structure) and multiple indexes(community and trophic structure).Biological warning system using online biomonitoring technology was divided into three classes(fish,invertebrate and microorganism).At present,index of biotic integrity can indicate water pollution better at community level.However,few studies focus on ecosystem-level warning.In this paper,ecological monitoring and warning based on community structure and the whole ecosystem level is proposed as the focus of future research direction.

Feasibility analysis of widely accepted indicators as key ones in river health assessment

Index systems on river health assessment are difficult for using in practice, due to the more complex and professional indicators adopted. In the paper, some key indicators which can be applied for river health assessment in general were selected, based on the analysis of 45 assessment index systems with 902 variables within around 150 published papers and documents in 1972–2010. According to the fields covered by the variables, they were divided into four groups: habitat condition, water environment, biotic status and water utilization. The adopted number and the accepted degrees in the above systems of each indicator were calculated after the variables were combined into the indicators, some of the widely accepted indicators which can reflect different aspects of river condition were selected as key indicators in candidate. Under the correlation analysis amongst the key indicators in candidate, 8 indicators were finally suggested as the key indicators for assessing river health, which were: coverage rate of riparian vegetation, reserved rate of wetland, river continuity, the changing rate of water flow, the ratio of reaching water quality standard, fish index of biotic integrity, the ratio of water utilization and land use.

Development of a fish‐based index of biotic integrity (FIBI) for monitoring riverine ecosystems in the Lake Victoria drainage Basin, Kenya

AbstractThe long term monitoring of aquatic ecosystems based on chemical analysis is expensive resulting in a lack of time series data for management purposes thus necessitating the need for new cost effective methodologies. This study developed a fish‐based index of biotic integrity (FIBI) for monitoring environmental conditions in riverine ecosystems within the Lake Victoria Basin, Kenya. The fish fauna in the basin is poorly studied, less diverse and ecologically specialized than the temperate fauna that provided the origins of the Index of Biotic Integrity. Fish samples were collected by electrofishing from 24 sites during baseflow periods in February, March and July 2004. Validation data were collected from 7 sites with varying levels of degradation. Fish samples were identified, counted and grouped into different trophic groups, relative tolerance to pollution, habitat guild and whether exotic or native to riverine environment. Thirty‐three candidate metrics were evaluated for responsiveness to habitat quality and twelve were selected for inclusion in the final index. The index classified 6 of the 7 validation sites according to their levels of degradation. As a bioassessment tool, the index was useful in laying the basis for long‐term monitoring of rivers in the Lake Victoria drainage basin. Copyright © 2010 John Wiley &amp; Sons, Ltd.