Benthic Response Index for Assessing Infaunal Communities on the Southern California Mainland Shelf

Abstract

Although benthic infaunal communities are commonly measured to assess the effectiveness of environmental management in protecting biological resources, the tools used to interpret the resulting data are often subjective or site specific. We present an objective, quantitative index for application throughout the southern California coastal shelf environment that measures the condition of a benthic assemblage, with defined thresholds for levels of environmental disturbance. The index was calculated using a two-step process in which ordination analysis was employed to quantify a pollution gradient within a 717sample calibration data set. The pollution tolerance of each species was determined based upon its distribution of abundance along the gradient. The index is calculated as the abundance-weighted average pollution tolerance of species in a sample. Thresholds were established for reference condition as well as for four levels of biological response. Reference condition was established as the index value in samples taken distant from areas of anthropogenic activity and for which no contaminants exceeded the effects range low (ERL) screening levels. The four response levels were established as the index values at which key community attributes were lost. Independent data sets were used to validate the index in three ways. First, index sensitivity to a spatial gradient of exposure to a discharge from a point source was tested. Second, index response to a temporal gradient of exposure to a discharge from a point source was examined, testing index robustness to natural temporal variation. Third, the effect of changes in natural habitat (e.g., substrate, depth, and latitude) on index sensitivity was tested by evaluating the ability of the index to segregate samples taken in areas with high and low chemical exposure, across a gradient of physical habitats.

Overview and application of the National Aquatic Ecological Monitoring Program (NAEMP) in Korea

“…For example, different mayfly taxa show variation in their ranges of tolerance to nutrient levels (Beketov, 2004). Thus the pollution tolerance of each taxon has been a key concept in developing indicators for the evaluation of diverse anthropogenic influences on stream ecosystems (Word, 1978(Word, , 1980(Word, , 1990Smith et al, 2001Smith et al, , 2007.…”

Review and evaluation of estuarine biotic indices to assess benthic condition

“…Benthic response index (BRI; Smith et al, 2001) The benthic response index (BRI) was developed for the Southern California coastal shelf and is a marine analogue of the Hilsenhoff index used in freshwater benthic assessments (Hilsenhoff, 1987). This index is calculated using a two-step method in which ordination analysis is employed to establish a pollution gradient.…”

“…So, if f = 1, the raw abundance values are used; if f = 0.5, the square root of the abundances are used; and if f = 0, I s is the arithmetic value of the p i values greater than zero, once that all a f si ¼ 1 (Smith et al, 2001). The average position for each species ( p i ) on the pollution gradient defined in the ordination space is measured as:…”

“…Although it can be useful to quantify disturbances, it is not able to distinguish between natural and anthropogenic disturbance, such as the natural impacts that river flows may have on benthic communities (Bergen et al, 2000). Nevertheless, this index presents the advantage of not underestimating biological effects, as well as presenting low seasonal variability (Smith et al, 2001). …”

Aquatic science and the water framework directive: a still open challenge towards ecogovernance of aquatic ecosystems

“…Moreover, even when restricting the field to a single BQE, i.e. benthic macro-invertebrates, ecological indicators were produced covering the full span from simple (Borja et al, 2000;Simboura and Zenetos, 2002) to complex (Fano et al, 2003), from multivariate (Smith et al, 2001) to multi-metric (Rosenberg et al, 2004;Muxika et al, 2007;Teixeira et al, 2009), from taxonomically selective (Gesteira and Dauvin, 2000;Dauvin and Ruellet, 2007) to taxonomically exhaustive (Borja et al, 2000;Simboura and Zenetos, 2002) and non-taxonomically based , addressing functional traits including body size traits (Reizopoulou and Nicolaidou, 2007) and ecosystem properties (exergy, Marques et al, 2003;Jorgensen, 2005). It gives a view of the complexity reached, which is contrasting with the aims of simplicity, generality and inter-comparability of the WFD.…”