Development and comparison of stream indices of biotic integrity using diatoms vs. non-diatom algae vs. a combination

Benthic soft-bodied algae as bioindicators of stream water quality

“…Potapova and Carlisle (2011) attributed the poor performance of soft-bodied algal metrics to the taxonomic method which precludes from species level identification and recommended development of new methods that better characterize the softbodied algal communities. Fetscher et al (2014) constructed the first IBIs based on soft-bodied algae alone derived from more than 451 stream samples collected predominantly in southern California (SWAMP, modified field method by Fetscher et al, 2009, and novel taxonomic method by Stancheva et al, 2012a). Soft-bodied algal metrics were taxonomic -algal phyla, indicator species and indicator guilds, and were expressed in two ways: proportion of total biovolume (relative biovolume), and proportion of total species number (relative species richness).…”

“…In addition, 5 diatom IBIs were constructed from the same data set. The best performing IBI in regards to the discriminatory power among the three site disturbance classes, and responsiveness to anthropogenic stress, signal-to-noise ratio, metric redundancy, and degree of indifference to natural gradients contains five diatom and three soft-bodied algal metrics (species indicators of low TP, high Cu and high DOC, ex- Fetscher et al, 2014. Legend: Lower-left triangle indicates the ZHR guild metric consisting of Zygnemataceae, heterocystous cyanobacteria and red algae; Upper-right triangle indicates the CRUS guild metric consisting of Cladophora glomerata L., Rhizoclonium hieroglyphicum (C. Agardh) Kütz., Ulva flexuosa Wulfen, and Stigeoclonium spp.…”

“…In Asia, many countries need capacity building programs to develop aquatic bioassessment techniques commonly used in Europe, US, Japan and South Korea (Goulden, 2011). Currently, softbodied algae metrics , Griffith et al, 2002Porter et al, 2008;Danielson et al, 2011;Potapova and Carlisle, 2011) and indices based solely on soft-bodied algae Schaumburg et al, 2004;Schneider andLindstrøm, 2009, 2011;Fetscher et al, 2014) have been developed for large-scale stream bioassessments in Europe and the US.…”

“…However, surprisingly little has been published addressing the performance of diatoms compared to soft-bodied algae as bioindicators (Lavoie et al, 2004;Kelly, 2006, Kelly et al, 2008, Schneider et al, 2012Stancheva et al, 2013b) or on the relative strength of indices derived from a single assemblage vs. combined assemblages (Potapova and Carlisle, 2011;Fetscher et al, 2014). Some of these studies (e.g., Lavoie et al, 2004;Kelly et al, 2008;Potapova and Carlisle, 2011) contribute to the impression that soft-bodied algae did not improve stressor responsiveness of diatoms alone, but they were based on taxonomy methods that allowed mainly genus-level or coarser identifications of soft-bodied algae which may account for the conclusions.…”

“…Some of these studies (e.g., Lavoie et al, 2004;Kelly et al, 2008;Potapova and Carlisle, 2011) contribute to the impression that soft-bodied algae did not improve stressor responsiveness of diatoms alone, but they were based on taxonomy methods that allowed mainly genus-level or coarser identifications of soft-bodied algae which may account for the conclusions. In contrast, studies designed to explore the full potential of soft-bodied algae demonstrated that they enhance bioassessment power along the following lines of consideration: (1) multimetric indices based on entire algal communities, created in southern Californian streams, showed better responsiveness to anthropogenic stress over indices based either on diatoms or soft-bodied algae assemblages alone (Fetscher et al, 2014); (2) the best performing softbodied algal index exhibited greater discriminatory power than its diatom counterpart near the higher end of the range of anthropogenic disturbance (Fetscher et al, 2014); (3) differences in diatom and soft-bodied algal biotic indices were detected in ecosystems which are subject to changing environmental conditions; these differences could provide indications related to ecosystem stability (Schneider et al, 2012); (4) diatom and soft-bodied algal communities respond to nutrient supply and pH differently, with diatom taxon richness generally increasing with nutrient availability in contrast to decreasing soft-bodied algae richness (Schneider et al, 2013); (5) diatoms in conjunction with soft-bodied algae provide a more robust assessment of nutrient conditions, inferring nitrogen (N) limitation in 20% more sites than monitoring with either algal group alone (Stancheva et al, 2013b).…”