The effect of excluding diatom taxa and reducing taxonomic resolution on multivariate analyses and stream bioassessment

Lavoie, Isabelle; Dillon, Peter J.; Campeau, Stéphane

doi:10.1016/j.ecolind.2008.04.003

Cited by 78 publications

(47 citation statements)

References 26 publications

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“…But does this extra information on biodiversity actually contribute to our knowledge about ecological status at a site? The nature of the metrics used in ecological assessments means that the amount of extra ecological information obtained from increased effort may be low (Lavoie et al, 2008a;Kelly & Ector, 2012;Rimet & Bouchez, 2012). If this is the case, then is there a case for more spatial and temporal replication at the expense of effort in the laboratory?…”

Section: Dealing With Variabilitymentioning

confidence: 99%

Data rich, information poor? Phytobenthos assessment and the Water Framework Directive

Kelly¹

2013

European Journal of Phycology

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The Water Framework Directive (WFD) provides the legal basis for water management in the European Union (EU). Twelve years after it was passed, all but five EU Member States had phytobenthos assessment methods for rivers, whilst nine had methods for lakes. Most are based on diatoms, although a few are supplemented by evaluations of non-diatoms and some include macroalgae as part of parallel macrophyte assessments. Norway is the exception, with assessment based on non-diatom algae alone. Over half of all states have methods based wholly or partly on weighted average metrics developed before the onset of the WFD, with nine choosing the Indice de Polluosensibilité Specifique. Such metrics generally have high correlations with the predominant nutrient or organic pollution gradient and, as such, represent pragmatic solutions to ecological status assessment. However, their widespread use raises questions about what, exactly, 'ecological status' means. Strong relationships with chemical pressure gradients may be a mixed blessing as pressure gradients are often composed of several intercorrelated variables, making it difficult to disentangle correlation and causation in the absence of ecophysiological studies of individual species. Moreover, the focus on strong relationships with chemical gradients means that most phytobenthos metrics describe the scale of hazard at a site rather than the risk posed to other trophic levels and to ecosystem services. This first generation of phytobenthos assessment tools may be inadequate when catchment managers need guidance on remediation strategies for particular water bodies. A second generation of assessment tools, focused on the fitness of the phytobenthos as part of aquatic ecosystems, rather than just as indicators of chemical conditions, is needed if the goal of good ecological status around Europe is to be achieved.

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Section: Dealing With Variabilitymentioning

confidence: 99%

Data rich, information poor? Phytobenthos assessment and the Water Framework Directive

Kelly¹

2013

European Journal of Phycology

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“…In all analyses, species that occurred in less than 2% of maximum density were removed from the data set to reduce the influence of rare taxa on multivariate analyses [32]. We analyzed differences among sampling depths and between the fen and bog zones (nominal variables) for the dominant testate amoeba species using a MANOVA test.…”

Section: Numerical Analysesmentioning

confidence: 99%

Fine-Scale Horizontal and Vertical Micro-distribution Patterns of Testate Amoebae Along a Narrow Fen/Bog Gradient

et al. 2010

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The ecology of peatland testate amoebae is well studied along broad gradient from very wet (pool) to dry (hummock) micro-sites where testate amoebae are often found to respond primarily to the depth to water table (DWT). Much less is known on their responses to finerscale gradients, and nothing is known of their possible response to phenolic compounds, which play a key role in carbon storage in peatlands. We studied the vertical (0-3, 3-6, and 6-9 cm sampling depths) micro-distribution patterns of testate amoebae in the same microhabitat (Sphagnum fallax lawn) along a narrow ecological gradient between a poor fen with an almost flat and homogeneous Sphagnum carpet (fen) and a "young bog" (bog) with more marked micro-topography and mosaic of poor fen and bog vegetation. We analyzed the relationships between the testate amoeba data and three sets of variables (1) "chemical" (pH, Eh potential, and conductivity), (2) "physical" (water temperature, altitude, i.e., Sphagnum mat micro-topography, and DWT), and (3) phenolic compounds in/from Sphagnum (water-soluble and primarily bound phenolics) as well as the habitat (fen/bog) and the sampling depth. Testate amoeba Shannon H′ diversity, equitability J of communities, and total density peaked in lower parts of Sphagnum, but the patterns differed between the fen and bog micro-sites. Redundancy analyses revealed that testate amoeba communities differed significantly in relation to Eh, conductivity, water temperature, altitude, water-soluble phenolics, habitat, and sampling depth, but not to DWT, pH, or primarily bound phenolics. The sensitivity of testate amoebae to weak environmental gradients makes them particularly good integrators of micro-environmental variations and has implications for their use in paleoecology and environmental monitoring. The correlation between testate amoeba communities and the concentration of water-soluble phenolic suggests direct (e.g., physiological) and/or indirect (e.g., through impact on prey organisms) effects on testate amoebae, which requires further research.

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“…The relative contribution of taxa richness and abundance to the integrity of ecosystems is a central question in ecology (Loreau, 2000;Gessner et al, 2004), and has important implications for the design of management tools that track ecosystem quality. In particular, the significance of rare taxa (i.e., few in numbers or absent from most samples) to assessments of aquatic system health has been the object of some debate (Cao et al, 1998;Marchant, 1999Marchant, , 2002Cao and Williams, 1999;Cao et al, 2001;Van Sickle et al, 2007;Lavoie et al, 2009). On the one hand, common or abundant taxa may provide an adequate indication of ecosystem health, with rare taxa not contributing significant additional information (Marchant, 1999(Marchant, , 2002Van Sickle et al, 2007;Lavoie et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the significance of rare taxa (i.e., few in numbers or absent from most samples) to assessments of aquatic system health has been the object of some debate (Cao et al, 1998;Marchant, 1999Marchant, , 2002Cao and Williams, 1999;Cao et al, 2001;Van Sickle et al, 2007;Lavoie et al, 2009). On the one hand, common or abundant taxa may provide an adequate indication of ecosystem health, with rare taxa not contributing significant additional information (Marchant, 1999(Marchant, , 2002Van Sickle et al, 2007;Lavoie et al, 2009). Moreover, efforts to account for the true abundance of rare taxa in the field are prone to large sampling variance, which in turn may create statistical noise that bias observed patterns in biological communities; more time is also required to identify rare taxa (Gauch, 1982).…”

Section: Introductionmentioning

confidence: 99%

“…In Minnesota, for example, the IBIs for fish assemblages (F-IBI) are used in conjunction with other relevant habitat, water chemistry and catchment data to determine whether stream sites should be listed as impaired as required by the section 303(d) of Clean Water Act. The effect of rare taxa on bioassessments has been studied most commonly for macroinvertebrate assemblage indicators (reviewed by Lavoie et al, 2009), but the influences of rare taxa on a fish assemblage index are relatively unknown. The objective of this study was to investigate the sensitivity of fish metrics and F-IBI scores to rare taxa.…”

Section: Introductionmentioning

confidence: 99%

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The impact of rare taxa on a fish index of biotic integrity

Wan

Chizinski

Dolph

et al. 2010

Ecological Indicators

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The effect of excluding diatom taxa and reducing taxonomic resolution on multivariate analyses and stream bioassessment

Cited by 78 publications

References 26 publications

Data rich, information poor? Phytobenthos assessment and the Water Framework Directive

Data rich, information poor? Phytobenthos assessment and the Water Framework Directive

Fine-Scale Horizontal and Vertical Micro-distribution Patterns of Testate Amoebae Along a Narrow Fen/Bog Gradient

The impact of rare taxa on a fish index of biotic integrity

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