The Effect of Hydrological Disturbance on the Impact of a Benthic Invertebrate Predator

Thomson, James R.; Lake, P. S.; Downes, Barbara J.

doi:10.2307/3071869

Cited by 18 publications

(27 citation statements)

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“…Disturbances affect animals, plants and micro-organisms (Pickett and White 1985), may alter the impact of predators (Connell 1975;Thomson et al 2002) and herbivores (Poff and Ward 1995;Nystrand and Granström 2000) on lower trophic levels, and may alter food web structure (Townsend et al 1998). Conceptual models predict that the influence of biotic factors on community structure will be affected by the strength of abiotic factors, spatial and temporal scale, and how well predators and prey are adapted to changes in local environmental conditions (Connell 1975;Peckarsky 1983;Menge and Sutherland 1987;Menge and Olson 1990;Wellborn et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Are impacts of an exotic predator on a stream food web influenced by disturbance history?

Nyström

McIntosh

2003

Oecologia

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Predatory species have been introduced to habitats spanning a wide range of environmental conditions. To better understand the consequences of predation in natural communities we need to examine how variations in abiotic factors modify the influence of predation. The effects of introduced predators may vary amongst habitats if natural disturbance affects the abundance and taxonomic composition of consumers and their resources, or the predator alters recolonisation after disturbance. We tested whether a bed-moving disturbance altered subsequent interactions involving native and introduced predatory fish, invertebrate grazers and algae in experimental channels within a New Zealand stream. Disturbance reduced the abundance of invertebrates by 84%, and induced mortality of Conoesucidae caddisflies. However, the relative abundance of taxa changed little immediately following the disturbance. Invertebrate communities recovered following disturbance in fishless channels and those with native galaxiids (Galaxias vulgaris), and were almost indistinguishable from undisturbed fishless controls after 2 weeks. Invertebrate abundance declined and algal abundance increased in channels with exotic brown trout (Salmo trutta) and their effect was strongest in previously disturbed channels. However, predators and disturbance only had interactive effects on grazer emigration rates. Trout affected grazers through direct consumption (e.g. Conoesucidae caddisflies), and induced higher emigration rates of grazers from channels via drift (e.g. the mayfly Deleatidium). The effects of predatory trout and galaxiids combined differed in disturbed and stable channels. The observed combined effects of predatory trout and galaxiids on invertebrate grazers were lower than expected in stable channels partly due to low emigration rates of Conoesucidae, whereas emigration of grazers was higher than expected in the disturbed channels. The biomass of algae was higher than expected in disturbed channels with both predators. Collectively, our results indicate that predator substitutability and the non-lethal effects of introduced predators varied depending on disturbance history, but their effects on the biomass of grazers and algae did not.

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Section: Introductionmentioning

confidence: 99%

Are impacts of an exotic predator on a stream food web influenced by disturbance history?

Nyström

McIntosh

2003

Oecologia

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“…Predators also showed higher density in patches with grasses in the wet season, and this may be due to prey availability, since most taxa were more abundant in these patches. Encounter rates between predators and prey may have increased during floods due to the concentration of macroinvertebrates in this refuge from hydrodynamic disturbance (Thomson et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

Influence of an exotic grass on benthic macroinvertebrate communities in a tropical rural landscape

Fonseca

Tanaka

2015

Hydrobiologia

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Riparian deforestation in rural areas has led to changes in bankside vegetation communities that may have unexpected effects on stream ecosystems. In particular, plants such as grasses can colonize the streambed from adjacent terrestrial habitats, thus altering the physical structure of the streambed and potential influencing macroinvertebrate communities. Here we evaluated if the presence of patches of grasses (Urochloa sp.) on the streambed influenced the structure and composition of macroinvertebrate communities in deforested rural streams. We sampled patches with and without grasses in three low-order streams, in the wet and dry seasons. We recorded higher abundances of macroinvertebrates in patches with grasses in the wet season when compared with bare patches. We also found significant differences in taxonomic and functional feeding group composition between patch types, due to higher overall abundances in patches with grasses, probably due to more food and shelter there. These influences were stronger in the wet season, when in-stream grasses may have provided greater refugia from flood disturbance that occur with increased frequency and intensity. Therefore, although deforestation of rural streams can simplify streambed habitats, in-stream grasses such as Urochloa sp. provide resources that contribute for the maintenance of macroinvertebrate communities.

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“…Apropos the many biotic factors, this stream is well‐endowed with large‐bodied predatory invertebrates (Lancaster et al. , 2005) and we know that many of their prey, such as mayflies, will drift away from patches with predators (Peckarsky, 1980; Lancaster, 1990; Thomson, Lake & Downes, 2002). More generally, mobile organisms integrate a range of flow conditions during their movements and this will generate scatter in density–flow relationships.…”

Section: Scatter In Abundance–environment Relationshipsmentioning

confidence: 99%

Defining the limits to local density: alternative views of abundance–environment relationships

Lancaster

Belyea

2006

Freshwater Biology

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1. In many ecosystems, the local abundance of organisms is spatially heterogeneous. Ecologists often seek to explain this variation by modelling the central tendency of abundance as a function of a single dominant factor (central response, CR). An alternative approach is to model maximum and minimum abundance in relation to the dominant factor (limiting response, LR), thereby acknowledging that multiple factors may constrain abundance and create scatter in the relationship. In many ecosystems, including streams, abundance-environment relationships are traditionally expected to be CR models with a single dominant factor determining local abundance, but this hypothesis lacks rigorous test. This omission is of concern because CR modelled relationships form the foundations of many ecological tests, predictive and management tools that, consequently, may provide erroneous interpretations. 2. In a survey designed to minimise variance in the data, we related densities of three taxa of stream invertebrates to near-bed flow. Data were analysed using both ordinary least squares (OLS) regression and quantile regression, which have different characteristic results depending on whether the relationship is better described as a CR or LR model. For all three taxa, invertebrate responses to flow conformed most closely to LR models and were best described by quantile regression, although OLS regression revealed broadly similar general trends in this case. 3. Based on the statistically modelled relationships, we were able to hypothesise which ecological mechanisms limited maximum abundance at this site, including dislodgement with high flow (Heptageniidae, Leuctridae), reduced oxygen uptake at low flow (Baetidae) and reduced provision of interstitial spaces at high flow (Leuctridae). Scatter in the relationships was attributable to multiple factors that may operate at different scales, including inter-individual variation, alternative environmental gradients and biotic processes at the patch scale, and potential constraints of dispersal and settlement operating outside the patch. 4. We illustrate how the choice of CR or LR model to describe abundance-environment relationships may affect tests of ecological theory and applied ecology. If our results are typical of other streams and other types of systems, greater use of LR models may

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The Effect of Hydrological Disturbance on the Impact of a Benthic Invertebrate Predator

Cited by 18 publications

References 0 publications

Are impacts of an exotic predator on a stream food web influenced by disturbance history?

Are impacts of an exotic predator on a stream food web influenced by disturbance history?

Influence of an exotic grass on benthic macroinvertebrate communities in a tropical rural landscape

Defining the limits to local density: alternative views of abundance–environment relationships

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