Effects of Herbivore Type and Density on Taxonomic Structure and Physiognomy of Algal Assemblages in Laboratory Streams

Steinman, Alan D.; McIntire, C. David; Gregory, S.; Lamberti, Gary A.; Ashkenas, Linda R.

doi:10.2307/1467509

Cited by 191 publications

(128 citation statements)

References 31 publications

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“…Studies have shown that macroinvertebrate herbivores can alter algal biomass and community composition (Steinman et al 1987;Feminella and Hawkins 1995). However, in this study, trophic groups were a significant predictor in only one of the RF models.…”

Section: Relationships Between Algae Metrics and Environmental Variablescontrasting

confidence: 76%

Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams

Black

Moran

Frankforter

2010

Environ Monit Assess

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Many streams within the United States are impaired due to nutrient enrichment, particularly in agricultural settings. The present study examines the response of benthic algal communities in agricultural and minimally disturbed sites from across the western United States to a suite of environmental factors, including nutrients, collected at multiple scales. The first objective was to identify the relative importance of nutrients, habitat and watershed features, and macroinvertebrate trophic structure to explain algal metrics derived from deposition and erosion habitats. The second objective was to determine if thresholds in total nitrogen (TN) and total phosphorus (TP) related to algal metrics could be identified and how these thresholds varied across metrics and habitats. Nutrient concentrations within the agricultural areas were elevated and greater than published threshold values. All algal metrics examined responded to nutrients as hypothesized. typically were the most important variables in explaining the variation in each of the algal metrics, environmental factors operating at multiple scales also were important. Calculated thresholds for TN or TP based on the algal metrics generated from samples collected from erosion and deposition habitats were not significantly different. Little variability in threshold values for each metric for TN and TP was observed. The consistency of the threshold values measured across multiple metrics and habitats suggest that the thresholds identified in this study are ecologically relevant. Additional work to characterize the relationship between algal metrics, physical and chemical features, and nuisance algal growth would be of benefit to the development of nutrient thresholds and criteria.

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Section: Relationships Between Algae Metrics and Environmental Variablescontrasting

confidence: 76%

Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams

Black

Moran

Frankforter

2010

Environ Monit Assess

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“…Likewise, stream algae are generally small, and the combination of small size and prostrate morphology increases resistance to loss from disturbances such as spateinduced floods (Blenkinsopp and Lock 1994;Peterson 1996) and grazing (Jacoby 1987;Steinman et al 1987;Lamberti et al 1989). Small size has the additional benefit of enabling organisms to fit within crevices.…”

mentioning

confidence: 99%

Crevices as refugia for stream diatoms: Effect of crevice size on abraded substrates

Bergey

1999

Limnology & Oceanography

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This study explored the mechanisms by which crevices act as refugia for small algae during abrasive disturbances. Four substrates with different crevice features were subjected to three levels of abrasion in a stream-based experiment. Substrates were sand-grain caddisfly cases and three glass rod substrates that mimicked caddisfly cases in size and shape, as well as forming a gradient of larger crevices (i.e., smooth with no crevices, sanded with shallow pits, and scratched with deeper grooves). Substrates were subjected to no, low, or high abrasion levels during 18 d of incubation by pulling substrates through a sand-gravel mixture in floating enclosures that housed the experiment. Diatom density, relative biovolume, location in crevices, detritus accumulation, and filamentous algal density were compared among substrate types and abrasion levels. Across all abrasion levels, diatom and filamentous algal densities were higher on caddisfly cases than on all three glass rod substrates. Although abrasion greatly reduced overall diatom density, diatoms within crevices were largely protected. Crevice size influenced diatom size and composition. The small crevices of sanded rods contained primarily small diatoms of a single species (Achnanthidium minutissimum), whereas the larger crevices of scratched rods and caddisfly cases contained a greater range of diatom size and, consequently, greater species diversity. Detritus accumulated in all crevices, and accumulation increased with level of abrasion. Diatom biovolume decreased and location in crevices increased with the level of abrasion on the less textured smooth and sanded glass rods. Abrasion level had little effect on algal assemblages on caddisfly cases. This study demonstrates that crevices can be important refugia from abrasive disturbances, and that the size of crevices relative to organismal size can influence the protective value of crevices.

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“…Midges preferentially consumed diatoms, as has previously been observed in the Eel River and in other studies (Power 1991, Á lvarez and Peckarsky 2005, Power et al 2009). Midges generally preferentially grazed or consumed upright or nonadnate diatoms relative to tightly attached, adnate cells like Cocconeis (Steinman et al 1987, McCormick and Stevenson 1989, Dudley 1992). In our study, the strength of the midge-algae interactions varied with Cladophora stage, evidenced by differences in % cover of upright, loosely attached, and tightly adhered epiphytes among stages.…”

Section: Direct Midge-algae Interactionsmentioning

confidence: 99%

“…The patchy distributions of periphyton in riverine benthic environments (Henry and Fisher 2003, Soininen 2003, Veselá 2009) also result in part from complex and varied interactions with grazers (Feminella andHawkins 1995, Liess andHillebrand 2004). Grazers can alter algal composition and density directly by grazing (Steinman et al 1987, Hillebrand 2002, 2008 or indirectly via excretion . Reciprocally, variation in periphyton composition and density can affect grazer fitness and survival, i.e., via differences in the quality and quantity of food (Gresens 1997, Hessen et al 2002 or by providing refuge.…”

mentioning

confidence: 99%

Midges,Cladophora, and epiphytes: shifting interactions through succession

et al. 2012

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Effects of Herbivore Type and Density on Taxonomic Structure and Physiognomy of Algal Assemblages in Laboratory Streams

Cited by 191 publications

References 31 publications

Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams

Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams

Crevices as refugia for stream diatoms: Effect of crevice size on abraded substrates

Midges,Cladophora, and epiphytes: shifting interactions through succession

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