Mechanisms influencing community composition and succession in mountain stream periphyton: interactions between scouring history, grazing, and irradiance

Wellnitz, Todd; Rader, Russell B.

doi:10.2307/1468350

Cited by 69 publications

(52 citation statements)

References 41 publications

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“…For each group of tiles, we attached 4 strips of tiles (2 3 6 tile arrangement, separated by 8 cm from adjacent strips) to wire fencing and staked them flush with the stream bottom. Grazers can have variable effects on algal biomass (Steinman and McIntire 1990, Steinman 1996, Wellnitz and Rader 2003, but we did not exclude them because of the difficulty associated with setting mesh that would exclude macroinvertebrates without altering flow or becoming clogged by leaves and debris. These obstacles are more readily circumvented in artificial stream mesocosms.…”

Section: Study Sitesmentioning

confidence: 99%

Acid mine drainage affects the development and function of epilithic biofilms in streams

Smucker

Vis

2011

Journal of the North American Benthological Society

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Section: Study Sitesmentioning

confidence: 99%

Acid mine drainage affects the development and function of epilithic biofilms in streams

Smucker

Vis

2011

Journal of the North American Benthological Society

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“…Gomphonema, which was generally abundant, was least numerous in NTC, and its erect, stalked growth form makes it vulnerable to grazers (Wellnitz et al, 1996;Wellnitz & Rader, 2003). Since Gomphonema is a major food of Pseudogastromyzon myersi (Yang & Dudgeon, 2009b), high fish densities at NTC might account for its scarcity.…”

Section: Wet Season Cyanobacteria Filamentousmentioning

confidence: 99%

Spatial and seasonal variations in benthic algal assemblages in streams in monsoonal Hong Kong

2009

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Samples from stone surfaces were collected in pools within four unpolluted hillstreams (two shaded and two unshaded) in monsoonal Hong Kong (lat. 23°N) to elucidate the extent of spatial (within and among streams) and temporal (seasonal) variations in algal biomass and assemblage composition. Sampling continued for over 12 months, incorporating the dry season when streams were at baseflow, and the wet season when spates were frequent. We anticipated that algal biomass would be lower in shaded streams and during the wet season, with associated seasonal differences in assemblage composition or relative abundance of different growth forms (e.g. erect versus prostrate). Benthic chlorophyll a (a proxy for algal biomass) varied among streams from an annual mean of 11.0-22.3 mg m -2. Dry-season standing stocks were 18% higher than during the wet season when spate-induced disturbance reduced algal standing stocks. Algal biomass varied significantly at the stream scale, but not at the pool scale, and was lower in unshaded streams, where standing stocks may have been limited by high densities of algivorous balitorid loaches (mainly Pseudogastromyzon myersi). An overriding effect of grazers on algal biomass could also have reduced variations resulting from spateinduced disturbance. Significant differences in assemblage composition among streams, which were dominated by diatoms and cyanobacteria (totally 82 taxa) were not systematically related to shading conditions. Seasonal variations in algal assemblages were statistically significant but rather minor, and did not involve major shifts in composition or growth form caused by spate-induced disturbance. The abundance of filamentous cyanobacteria in all the streams may have been due to 'gardening' by balitorid loaches that removed erect or stalked diatoms and favoured cyanobacteria that persist through basal regeneration of filaments. This explanation requires validation through manipulative experiments.

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“…trophic conditions (e.g. Cattaneo et al, 1997;Veraart et al, 2008), hydrological conditions (Biggs et al, 1998), grazing pressure (Wellnitz and Rader, 2003) and water chemistry and temperature (Brown et al, 2008). In addition, it has been known for decades that communities of benthic algae and cyanobacteria are sensitive to various types of disturbance, e.g.…”

Section: Benthic Primary Producersmentioning

confidence: 99%

Scientific Opinion on the effect assessment for pesticides on sediment organisms in edge‐of‐field surface water

2015

EFS2

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The EFSA Panel on Plant Protection Products and their Residues (PPR Panel) was tasked to revise the Guidance Document (GD) on Aquatic Ecotoxicology under Council Directive 91/414/EEC (SANCO/3268/2001 rev. 4 (final), 17 October 2002. This scientific opinion of the PPR Panel is the second of three requested deliverables within this mandate. The scientific background for the risk assessment on sediment organisms in edge-of-field surface waters is provided, with reference to benthic ecology and ecotoxicology, available test protocols and current knowledge on exposure and effects of sediment-bound plant protection products (PPPs). The scientific opinion provides approaches on how to derive regulatory acceptable concentrations (RACs) for sediment organisms and exposure to active substances of PPPs and transformation products of these substances, and how to link them in a tiered approach to predicted environmental concentrations (PECs) for the sediment compartment. A list of uncertainties in relation to such approaches is given. SUMMARYSediment Environmental Risk Assessment (ERA) is a combination of exposure and effect assessment. Proposals for these assessments are provided. The opinion describes specific protection goals (SPGs) for sediment-inhabiting organisms based on two options (1) the ecological threshold option (ETO), accepting negligible population effects only, and (2) if applicable, the ecological recovery option (ERO), accepting some population-level effects if ecological recovery takes place within an acceptable time period.Triggers for sediment ecotoxicity testing are proposed together with a decision scheme for when additional testing may be required. The ecotoxicologically relevant concentrations (ERCs) for sediment organisms are proposed, as this will be influenced by the choice of sediment layer, exposure metric and test duration.The current Forum for the co-ordination of pesticide fate models and their use (FOCUS) methodology for surface water does not consider the effect of multi-year applications, which could possibly lead to accumulation of pesticides in sediment. To account for this deficit, a proposed methodology for introducing an accumulation factor that can be used until an updated FOCUS methodology becomes available is presented in this opinion. The accumulation factor can be considered a conservative approach, since it does not include any possible transport processes, such as leaching or volatilisation, which may reduce the accumulation in sediment in the real field situation.A tiered effect assessment approach is proposed for different sediment organisms and how to link regulatory acceptable concentrations (RACs) to predicted environmental concentration (PECs). The assessment of bioaccumulation, biomagnification and secondary poisoning is discussed, as well as the prospect of improving ERA for sediment microorganisms.Transformation products from active substances also may need to be assessed, as well as mixture toxicity of formulations of plant protection products (PPPs). The op...

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Mechanisms influencing community composition and succession in mountain stream periphyton: interactions between scouring history, grazing, and irradiance

Cited by 69 publications

References 41 publications

Acid mine drainage affects the development and function of epilithic biofilms in streams

Acid mine drainage affects the development and function of epilithic biofilms in streams

Spatial and seasonal variations in benthic algal assemblages in streams in monsoonal Hong Kong

Scientific Opinion on the effect assessment for pesticides on sediment organisms in edge‐of‐field surface water

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