The effects of floods on the invertebrate fauna of a large, unstable braided river

Sagar, P. M.

doi:10.1080/00288330.1986.9516127

Cited by 98 publications

(104 citation statements)

References 13 publications

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“…Hydrological disturbances are believed to reduce invertebrate abundance and diversity in two waysdirectly by washing away and crushing individuals (Sagar 1986;Reice et al 1990) and indirectly by reducing primary productivity or the abundance of periphyton (Robinson & Minshall 1986;Death 1996). In this study, disturbance reduced periphyton biomass but not nearly as dramatically as the artificial cover did.…”

Section: Discussionmentioning

confidence: 65%

Effect of substrate stability and canopy cover on stream invertebrate communities

Zimmermann

Death²

2002

New Zealand Journal of Marine and Freshwater Research

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Disturbance can be an important determinant of stream benthic invertebrate community structure. Whether this is a result of the direct loss of invertebrates, an alteration to the food base of the community by the disturbance, or a combination of both, is never clear. We examined this question by conducting a disturbance experiment under artificial cover where low light limited periphyton growth and minimised the effect of disturbance on periphyton abundance. The experiment was conducted using baskets of natural substrate in a spring-fed Taranaki Ring Plain stream, Taranaki, New Zealand during February and March 2000. Baskets were placed in the open or under cover and half were disturbed every week for 4 weeks. The artificial cover dramatically reduced periphyton biomass. Presence or absence of cover was the primary determinant of what invertebrate taxa dominated in the baskets, most likely as a result of differences in food resources. The filter feeding Coloburiscus humeralis dominated numerically in the covered baskets, whereas the generalist grazers Deleatidium spp., Beraeoptera roria, Orthocladiinae, and Diamesinae dominated numerically in the open baskets. However, cover had no effect on the overall abundance and species richness of the experimental baskets but disturbance reduced abundance and to a lesser extent species richness.

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Section: Discussionmentioning

confidence: 65%

Effect of substrate stability and canopy cover on stream invertebrate communities

Zimmermann

Death²

2002

New Zealand Journal of Marine and Freshwater Research

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“…These indices quantified the frequency with which variables exceeded or fell below certain thresholds. Threshold values were taken from a range of published observational and experimental studies (Sagar, 1986;Edwards et al, 1990;Mason, 1990;Clausen and Biggs, 1997).…”

Section: Methodsmentioning

confidence: 99%

Seasonality, water quality trends and biological responses in four streams in the Cairngorm Mountains, Scotland

Soulsby

Malcolm

Gibbins

et al. 2001

Hydrol. Earth Syst. Sci.

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The chemical composition and invertebrate communities found in four streams in the Cairngorms, Scotland, were monitored between [1985][1986][1987][1988][1989][1990][1991][1992][1993][1994][1995][1996][1997]. Stream waters were mildly acidic (mean pH ca. 6.5), with low alkalinity (mean acid neutralising capacity varying from 35-117 meq l -1 ) and low ionic strength. Subtle differences in the chemistry of each stream were reflected in their invertebrate faunas. Strong seasonality in water chemistry occurred, with the most acid, low alkalinity waters observed during the winter and early spring. This was particularly marked during snowmelt between January and April. In contrast, summer flows were usually groundwater dominated and characterised by higher alkalinity and higher concentrations of most other weathering-derived solutes. Seasonality was also clear in the invertebrate data, with Canonical Correspondence Analysis (CCA) separating seasonal samples along axes related to water temperature and discharge characteristics. Inter-annual hydrological and chemical differences were marked, particularly with respect to the winter period. Invertebrate communities found in each of the streams also varied from year to year, with spring communities significantly more variable (P<0.01) than other seasons (quantified using Euclidean distance on CCA ordinations). Hydrochemical trends over the study period were analysed using a seasonal Kendall test, LOcally WEighted Scatterplot Smoothing (LOWESS) and graphical techniques. These indicated that a reduction in sulphate concentrations in stream water is occurring, consistent with declining levels of atmospheric deposition. This may be matched by increases in pH and declining calcium concentrations, though available evidence is inconclusive. Other parameters, such as chloride, total organic carbon and zinc, reveal somewhat random patterns, probably reflecting irregular variations in climatic factors and/or atmospheric deposition. Previous studies have shown that the stream invertebrate communities have remained stable over this period (i.e. no significant linear trends) and show no evidence of acid-related impoverishment. Thus, over longer timescales invertebrates in these streams appear robust to the short-term (seasonal and inter-annual) environmental variability and long-term (decadal) chemical changes identified.

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“…However, most of this published research has focused on main channel habitats (e.g. Sagar 1986;Scrimgeour & Winterbourn 1989), and within braided river landscapes the importance of springs and spring-fed channels has received little attention until recently (see section 3.4.1).…”

Section: 4 T H E C O N T R I B U T I O N O F S P R I N G S T O B I mentioning

confidence: 99%

Crenic habitats, hotspots for freshwater biodiversity conservation: toward an understanding of their ecology

et al. 2012

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The effects of floods on the invertebrate fauna of a large, unstable braided river

Cited by 98 publications

References 13 publications

Effect of substrate stability and canopy cover on stream invertebrate communities

Effect of substrate stability and canopy cover on stream invertebrate communities

Seasonality, water quality trends and biological responses in four streams in the Cairngorm Mountains, Scotland

Crenic habitats, hotspots for freshwater biodiversity conservation: toward an understanding of their ecology

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