Literatura académica sobre el tema "Macroinvertebrate grazers"

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Artículos de revistas sobre el tema "Macroinvertebrate grazers"

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Jordan, J. y PS Lake. "Grazer-epilithon interactions in an Australian upland stream". Marine and Freshwater Research 47, n.º 6 (1996): 831. http://dx.doi.org/10.1071/mf9960831.

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Effects of macroinvertebrate grazers on the distribution of their food resource, epilithon, were examined in a south-eastern Australian stream. The hypothesis that grazers would significantly alter the development of epilithon was tested experimentally: macroinvertebrates were excluded from some experimental substrata and allowed to colonize others. Epilithic chlorophyll a concentration, organic matter content and total diatom density were used to monitor the effects of the grazer assemblage over 35 days. As predicted, epilithon density was higher on bricks with exclusion barriers than on bricks open to colonization by grazers. Similarly, diatom densities were significantly higher on bricks from the grazer-exclusion treatment. Patterns in the development of epilithon over time point to the importance of prevailing abiotic conditions in determining the outcome of macroinvertebrate grazing. Differences in total epilithon biomass, algal biomass and diatom density between treatments clearly indicate the independent importance of macroinvertebrate grazing to the microdistribution of epilithon in upland streams.
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Krist, Amy y Caroline Charles. "Comparison of Grazing Impacts Between the Invasive New Zealand Mudsnail Potamopyrgus Antipidarum, and Native Macroinvertebrates". UW National Parks Service Research Station Annual Reports 31 (1 de enero de 2008): 97–107. http://dx.doi.org/10.13001/uwnpsrc.2008.3715.

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To understand the impacts of an herbivorous invasive species on native herbivores, it is critical to quantify the relative impact of the invasive and the native species on shared resources. In a field experiment, we compared grazing efficacy of periphyton by the invasive New Zealand mudsnail, Potamopyrgus antipidarum, and 3 native macroinvertebrate grazers. Depending on the measure of periphyton biomass, P. antipodarum removed as much or more periphyton than any of the native grazers. When we examined diatom genera individually, P. antipodarum also suppressed the relative abundance of the greatest number of diatom genera and suppressed those diatoms more than the native grazers. As a result, P. antipodarum should compete strongly for periphyton with native grazers. In particular, because Ephemerella mayflies were the second most effective grazers and grazed many diatom genera similarly to the invasive snails, these mayflies may be competing with P. antipodarum in the introduced range. Overall, grazing ability may contribute to the invasion success of P. antipodarum.
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Řezníčková, Pavla, Lenka Tajmrová, Petr Pařil y Světlana Zahrádková. "Effects of drought on the composition and structure of benthic macroinvertebrate assemblages – a case study". Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 61, n.º 6 (2013): 1853–65. http://dx.doi.org/10.11118/actaun201361061853.

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Natural drying up of streams is not common in Central Europe. Nevertheless, the recurrent drying up of small streams in last decades has shown an urgent need to pay attention to the impact of global climate change. This strong disturbance influences conditions in streams markedly and causes changes in the taxonomical and functional structure of biota. The aim of the study was to compare aquatic macroinvertebrate assemblages of one intermittent and one permanent brook in South Moravia. The study was carried out in two stretches with otherwise comparable environmental parameters. Lower densities of macroinvertebrates were found at the intermittent site the difference was statistically significant. The number of taxa and diversity were significantly higher at the permanent site. Functional structure of the assemblages also varied. The shares of rheobionts, grazers and predators differed.
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Cremona, Fabien, Dolors Planas y Marc Lucotte. "Assessing the importance of macroinvertebrate trophic dead ends in the lower transfer of methylmercury in littoral food webs". Canadian Journal of Fisheries and Aquatic Sciences 65, n.º 9 (septiembre de 2008): 2043–52. http://dx.doi.org/10.1139/f08-116.

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Total mercury and methylmercury concentrations ([THg], [MeHg]) were measured in littoral macroinvertebrates from Lake St. Pierre, Quebec, Canada. Functional groups (detritivore, grazer, edible predator, inedible predator) explained the greatest fraction of [MeHg] variation compared with time (year, month), and space (station and shore). Greatest [THg] and [MeHg] were found in inedible predators mostly from families of heteropterans and coleopterans. Detritivores and grazers exhibited the lowest Hg concentrations, while edible predators were intermediate. Inedible predators also had the highest percentage of MeHg ([MeHg]/[THg]), with some taxa close to 100%. Such high percentages are seldom observed in freshwater organisms other than piscivorous fish. MeHg burden (concentrations × biomass) in inedible predators accounted for 10% of the MeHg pool for the whole invertebrate community. These large quantities of MeHg are sequestrated in aquatic “trophic dead ends” and could partly explain the low [MeHg] measured in fish, compared with [MeHg] of macroinvertebrates from Lake St. Pierre and other freshwater ecosystems with large littoral zones. We recommend taking into account the inedible organisms in Hg cycling models to avoid a possible overestimation of the MeHg pool available to fish.
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Merten, Eric C., William D. Hintz, Anne F. Lightbody y Todd Wellnitz. "Macroinvertebrate grazers, current velocity, and bedload transport rate influence periphytic accrual in a field-scale experimental stream". Hydrobiologia 652, n.º 1 (26 de junio de 2010): 179–84. http://dx.doi.org/10.1007/s10750-010-0329-1.

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Klumpp, D. W., J. S. Salita-Espinosa y M. D. Fortes. "The role of epiphytic periphyton and macroinvertebrate grazers in the trophic flux of a tropical seagrass community". Aquatic Botany 43, n.º 4 (noviembre de 1992): 327–49. http://dx.doi.org/10.1016/0304-3770(92)90046-l.

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Brock, T. C. M., R. M. M. Roijackers, R. Rollon, F. Bransen y L. van der Heyden. "Effects of nutrient loading and insecticide application on the ecology of Elodea-dominated freshwater microcosms II. Responses of macrophytes, periphyton and macroinvertebrate grazers". Archiv für Hydrobiologie 134, n.º 1 (28 de junio de 1995): 53–74. http://dx.doi.org/10.1127/archiv-hydrobiol/134/1995/53.

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Fournier, Robert J. y Daniel D. Magoulick. "Drought and nutrient pollution produce multiple interactive effects in stream ecosystems". PLOS ONE 17, n.º 7 (14 de julio de 2022): e0269222. http://dx.doi.org/10.1371/journal.pone.0269222.

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Drought and nutrient pollution can affect the dynamics of stream ecosystems in diverse ways. While the individual effects of both stressors are broadly examined in the literature, we still know relatively little about if and how these stressors interact. Here, we performed a mesocosm experiment that explores the compounded effects of seasonal drought via water withdrawals and nutrient pollution (1.0 mg/L of N and 0.1 mg/L of P) on a subset of Ozark stream community fauna and ecosystem processes. We observed biological responses to individual stressors as well as both synergistic and antagonistic stressor interactions. We found that drying negatively affected periphyton assemblages, macroinvertebrate colonization, and leaf litter decomposition in shallow habitats. However, in deep habitats, drought-based increases in fish density caused trophic cascades that released algal communities from grazing pressures; while nutrient enrichment caused bottom-up cascades that influenced periphyton variables and crayfish growth rates. Finally, the combined effects of drought and nutrient enrichment interacted antagonistically to increase survival in longear sunfish; and stressors acted synergistically on grazers causing a trophic cascade that increased periphyton variables. Because stressors can directly and indirectly impact biota—and that the same stressor pairing can act differentially on various portions of the community simultaneously—our broad understanding of individual stressors might not adequately inform our knowledge of multi-stressor systems.
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Akamagwuna, Frank Chukwuzuoke, Augustine Ovie Edegbene, Phindiwe Ntloko, Francis Ofurum Arimoro, Chika Felicitas Nnadozie, Dennis Junior Choruma y Oghenekaro Nelson Odume. "Functional groups of Afrotropical EPT (Ephemeroptera, Plecoptera and Trichoptera) as bioindicators of semi-urban pollution in the Tsitsa River Catchment, Eastern Cape, South Africa". PeerJ 10 (15 de diciembre de 2022): e13970. http://dx.doi.org/10.7717/peerj.13970.

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We examined the distribution patterns of Ephemeroptera, Plecoptera, and Trichoptera functional feeding groups (EPT FFGs) in five streams that drain semi-urban landscapes in the Tsitsa River catchment, Eastern Cape Province of South Africa. We undertook macroinvertebrate and physicochemical analysis over four seasons between 2016 and 2017 at eight sites in three land-use categories (Sites 1, 2 and 3), representing an increasing gradient of semi-urban pollution. Five EPT FFGs (shredders, grazers/scrapers, predators, collector-gatherers and collector-filterers) were fuzzy coded and analyzed using RLQ-R (environmental characteristics of samples), L (taxa distribution across samples) and Q (species traits) and fourth-corner analyses. Physicochemical variables, including phosphate-phosphorus, total inorganic nitrogen and temperature, were the most influential variables that significantly influenced the distribution patterns of EPT FFGs in the Tsitsa River. RLQ and the fourth-corner model revealed varying responses of FFGs to semi-urban pollution. Of the five FFGs, collectors were the most abundant EPT FFGs in the study area, exhibiting disparate responses to disturbances, with collector-gatherers associated with impacted sites and significantly associated with phosphate-phosphorus. On the other hand, collector-filterers decreased with increasing semi-urban disturbance and exhibited a significant negative association with phosphate-phosphorus, total inorganic nitrogen and temperature. Overall, this study provides further insights into the environmental factors that influence the distribution patterns of FFGs in Afrotropical streams and the potential use of FFGs as indicators of anthropogenic pollution in tropical streams and rivers.
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Stewart, Timothy W., Jeffrey G. Miner y Rex L. Lowe. "An experimental analysis of crayfish (Orconectes rusticus) effects on a Dreissena-dominated benthic macroinvertebrate community in western Lake Erie". Canadian Journal of Fisheries and Aquatic Sciences 55, n.º 4 (1 de abril de 1998): 1043–50. http://dx.doi.org/10.1139/f98-022.

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Quantitative descriptions of trophic interactions between Dreissena (zebra and quagga mussels) and other organisms are needed for an understanding of Dreissena's effects on energy flow and community dynamics in the Great Lakes. We used a field experiment to quantify effects of crayfish (Orconectes rusticus) predation on a Dreissena-dominated benthic macroinvertebrate community in western Lake Erie. Rocks colonized by Dreissena and associated macroinvertebrates were placed in cages and cageless reference plots located at a depth of 4 m. Crayfish (0, 8.3, and 20.8 individuals ·m-2) placed in cages were allowed to graze for 28 days. Dreissena had a greater effect than crayfish on the macroinvertebrate community, with positive relationships observed between Dreissena densities and both total macroinvertebrate biomass and densities of the amphipod Gammarus fasciatus. However, crayfish at densities of 20.8 individuals ·m-2 still reduced non-Dreissena macroinvertebrate biomass and Gammarus densities by 33 and 37%, respectively, relative to crayfish exclosures. Crayfish had negligible effects on Dreissena densities or shell length frequency distribution. Because crayfish and amphipods are prey for several fish species, trophic interactions among Dreissena, amphipods, and crayfish may be important in channeling energy from Dreissena to higher trophic levels in the Great Lakes.
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Tesis sobre el tema "Macroinvertebrate grazers"

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McKenny, Claire y n/a. "The Diversity of Macroinvertebrate Grazers in Streams: Relationships With the Productivity and Composition of Benthic Algae". Griffith University. Australian School of Environmental Studies, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060308.131239.

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There has been much interest in the last decade concerning the factors that influence diversity, especially how diversity and ecosystem processes may be linked. This study was based in small, cobble streams in South East Queensland. Its aim was to determine how the diversity and composition of consumers (the grazer guild) is influenced by both the production and composition of benthic algae, at different spatial scales. It also aimed to ascertain whether this response differs among grazer sub guilds with different dispersal capabilities. Ten sites in the Upper Brisbane and Mary catchments were sampled. The sites were selected to provide a range of productivity and composition. Grazers from these sites included snails and elmids, and larval mayflies, moths, and caddisflies. Grazer diversity and composition appeared to be structured by catchment scale influences, but environmental variables also affected which animals colonised patches and microhabitats (cobbles) within catchments. Primary productivity and algal composition could not be separated, with highly productive reaches also having a high cover of filamentous algal taxa. Grazer diversity displayed strongly positive, linear relationships with algal variables at the reach scale. It had a negative relationship with filamentous algae at the cobble scale, and a non-significant hump-shaped relationship with primary productivity. Survey data alone could not separate whether grazers were responding to habitat or food-related drivers, or to variations in productivity. Experimental manipulation of algal variables at the patch scale, using light and nutrients, also could not clearly uncouple the relationship between primary productivity and filamentous algal cover. Once reach scale variation was removed, grazer diversity displayed hump-shaped relationships with algal variables, including algal diversity. Much of this variation was due to patterns in mobile grazers, as sedentary grazers did not respond to algal variation at this scale. The density of the more mobile taxa showed similar patterns to those at the cobble scale (hump-shaped). A second field experiment was carried out in order to further investigate the responses of invertebrates to algal community composition at the cobble scale. Data from all three chapters suggested that as sites shifted to a dominance of filamentous algae, often with an associated increase in GPP, there was also a shift in the grazer community towards more sedentary grazers and away from the more mobile taxa. This also occurred at the cobble scale in the second experiment. The gut analysis and diet studies in the third chapter indicated that while many grazers consumed filamentous algae, it was not assimilated. This suggests that the preferences for sedentary taxa for cobbles and reaches dominated by filamentous algae are likely to be due to some other, possibly habitat-related, factor such as flow or predation refuge. The study provides a rare examination of relationships between primary productivity and consumer diversity in freshwater streams, and finds support for the pattern found in other systems of monotonic relationships of these two variables at large scales and hump-shaped relationships at smaller scales. It emphasises the importance of understanding other, potentially confounding, aspects of communities of producers, and investigates the possible roles of the most important of these (community composition) in structuring consumer communities in the small cobble streams of South-East Queensland.
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2

McKenny, Claire. "The Diversity of Macroinvertebrate Grazers in Streams: Relationships With the Productivity and Composition of Benthic Algae". Thesis, Griffith University, 2005. http://hdl.handle.net/10072/368092.

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There has been much interest in the last decade concerning the factors that influence diversity, especially how diversity and ecosystem processes may be linked. This study was based in small, cobble streams in South East Queensland. Its aim was to determine how the diversity and composition of consumers (the grazer guild) is influenced by both the production and composition of benthic algae, at different spatial scales. It also aimed to ascertain whether this response differs among grazer sub guilds with different dispersal capabilities. Ten sites in the Upper Brisbane and Mary catchments were sampled. The sites were selected to provide a range of productivity and composition. Grazers from these sites included snails and elmids, and larval mayflies, moths, and caddisflies. Grazer diversity and composition appeared to be structured by catchment scale influences, but environmental variables also affected which animals colonised patches and microhabitats (cobbles) within catchments. Primary productivity and algal composition could not be separated, with highly productive reaches also having a high cover of filamentous algal taxa. Grazer diversity displayed strongly positive, linear relationships with algal variables at the reach scale. It had a negative relationship with filamentous algae at the cobble scale, and a non-significant hump-shaped relationship with primary productivity. Survey data alone could not separate whether grazers were responding to habitat or food-related drivers, or to variations in productivity. Experimental manipulation of algal variables at the patch scale, using light and nutrients, also could not clearly uncouple the relationship between primary productivity and filamentous algal cover. Once reach scale variation was removed, grazer diversity displayed hump-shaped relationships with algal variables, including algal diversity. Much of this variation was due to patterns in mobile grazers, as sedentary grazers did not respond to algal variation at this scale. The density of the more mobile taxa showed similar patterns to those at the cobble scale (hump-shaped). A second field experiment was carried out in order to further investigate the responses of invertebrates to algal community composition at the cobble scale. Data from all three chapters suggested that as sites shifted to a dominance of filamentous algae, often with an associated increase in GPP, there was also a shift in the grazer community towards more sedentary grazers and away from the more mobile taxa. This also occurred at the cobble scale in the second experiment. The gut analysis and diet studies in the third chapter indicated that while many grazers consumed filamentous algae, it was not assimilated. This suggests that the preferences for sedentary taxa for cobbles and reaches dominated by filamentous algae are likely to be due to some other, possibly habitat-related, factor such as flow or predation refuge. The study provides a rare examination of relationships between primary productivity and consumer diversity in freshwater streams, and finds support for the pattern found in other systems of monotonic relationships of these two variables at large scales and hump-shaped relationships at smaller scales. It emphasises the importance of understanding other, potentially confounding, aspects of communities of producers, and investigates the possible roles of the most important of these (community composition) in structuring consumer communities in the small cobble streams of South-East Queensland.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
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McKenny, Claire. "The Diversity of macroinvertebrate grazers in streams relationships with the productivity and composition of benthic algae /". Click here to access, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060308.131239.

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Capítulos de libros sobre el tema "Macroinvertebrate grazers"

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Holomuzki, Joseph R. y Barry J. F. Biggs. "Food limitation affects algivory and grazer performance for New Zealand stream macroinvertebrates". En Advances in Algal Biology: A Commemoration of the Work of Rex Lowe, 83–94. Dordrecht: Springer Netherlands, 2006. http://dx.doi.org/10.1007/1-4020-5070-4_6.

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