The influence of an ecosystem-level manipulation on prey consumption by a lotic dragonfly

1987 ◽  
Vol 65 (1) ◽  
pp. 35-40 ◽  
Author(s):  
J. Bruce Wallace ◽  
T. F. Cuffney ◽  
C. C. Lay ◽  
D. Vogel
Keyword(s):  
Community Structure ◽  
Initial Treatment ◽  
Standing Stock ◽  
Generalist Predators ◽  
Invertebrate Drift ◽  
Total Biomass ◽  
Total Abundance ◽  
Stock Biomass ◽  
Reference Stream ◽  
Invertebrate Biomass

Pesticide application to a small headwater stream (treatment stream) resulted in massive invertebrate drift and altered community structure with respect to both biomasses and densities. The community changed from one dominated by insects to one of primarily noninsects. Insects represented 71 to 78% of total abundance and about 95% of total biomass in an adjacent reference stream during 2 years of study. During the initial treatment year, insects, mainly Chironomidae, composed less than 20% of total invertebrate biomass (<10% of abundance) in litterbags in the treatment stream. Within 2 years of the initial disturbance, invertebrate biomass in the treatment stream was again dominated by insects (90% of total) although insects represented only 36% of total abundance. Lanthus vernalis Carle (Odonata: Gomphidae) was among the insect taxa least affected by the treatment. Diets of larval Lanthus (gut analyses) reflected changes in community structure within the treatment stream, with insects representing only 13% of the prey during the initial treatment year and more than 82% during the 2nd year of recovery. In contrast, Lanthus in the reference stream consumed primarily insects (73 to 78%) in both years. These data indicate that generalist predators such as Lanthus can readily shift to alternative prey when confronted by massive changes in community structure. The results suggest that this disturbance reduced the abundance of the more profitable prey to a level where less profitable prey increased in the diet. Following the disturbance, Lanthus consumption reflected the recovery of more profitable prey in the environment. Secondary production of Lanthus approached 27% of average standing stock biomass of invertebrates in litterbags in each stream and, based on literature values for bioenergetic efficiencies, Lanthus consumed about 65% of the average standing stock biomass of invertebrates. Total consumption necessary to support production of all invertebrate predators may exceed the average standing stock prey biomass by 2.5 to 2.7 times. However, when prey turnover is considered, the potential impact of this predation on invertebrate community structure may be quite modest.

scholarly journals Fauna asociada a la pesquería de Arca Zebra (Mollusca Bivalvia: Arcidae) en Venezuela

2018 ◽  
Vol 47 (1) ◽  
Author(s):  
Roberto Díaz-Fermín ◽  
Vanessa Acosta-Balbás
Keyword(s):  
Community Structure ◽  
New Record ◽  
Diversity Index ◽  
Economic Viability ◽  
Total Biomass ◽  
Total Abundance ◽  
Physical Damage ◽  
Negative Effect ◽  
Fishing Resources ◽  
Pinctada Imbricata

Arca zebra, constitutes one of the fishing resources with the greatest economic impact in northeastern Venezuela, since it forms banks of commercial importance. During a period of nine months (May 2010-August2011) the community structure of the organisms from the trawling fishery carried out by the fishermen of the area was identified, quantified and described. The biomass and abundance of the different groups were estimated to perform Abundance-Biomass Comparison Curves (ABC) with the objective of determining the degree of affectation by the trawling activity. A total of3 249 organisms belonging to 130 species were grouped in five Phyla: Mollusca, Annelida, Arthropoda, Echinodermata and Chordata. The Sanders' diversity index was 122.9 with mollusks (70.87) and polychaetes (29.91) as the most diverse taxa. Mollusks had the highest abundance followed by polychaetes, crustaceans, echinoderms and ascidians. Mollusks and echinoderms made the largest contribution to total biomass. The most frequent species were: Mithraculus forceps, Phallucia nigra, Echinometra lucunter, Eunice rubra and Pinctada imbricata. The microgastropods Triphora melanura is recognized as a new record for the area and the polychaete Oenone fulgida, for Venezuela. The ABC curve showed that total abundance of organisms was above total biomass, suggesting that the fishery of Arca zebra has a negative effect on most groups of organisms, mainly on echinoderms, since many of them suffer strong physical damage at the time of extraction, therefore, there is a need to modify the trawl nets, increasing the mesh opening, butwithout endangering the economic viability of the fishery.

Population and Community Patterns of Invertebrate Drift in an Unregulated Coastal Plain River

1991 ◽  
Vol 48 (5) ◽  
pp. 811-823 ◽  
Author(s):  
Arthur C. Benke ◽  
Keith A. Parsons ◽  
Sunita M. Dhar
Keyword(s):  
Coastal Plain ◽  
Standing Stock ◽  
Dry Mass ◽  
Early Spring ◽  
Invertebrate Drift ◽  
Seasonal Patterns ◽  
Community Patterns ◽  
Preferred Habitat ◽  
Stock Biomass ◽  
Ogeechee River

Drifting invertebrates were sampled monthly during postdusk hours for 2 yr in the Ogeechee River, a sixth-order river in the southeastern United States. Drift quantities were among the highest reported in the literature, with mean biomass varying from 2.41 to 2.46 mg dry mass/m3 between years and mean density from 20.4 to 22.8 individuals/m3. Major contributors to drift biomass were Ephemeroptera (30.3%), Coleoptera (25.1%), Plecoptera (16.6%), and Trichoptera (14.5%). Taxon-specific seasonal patterns of drift biomass for several mayflies (Ephemerellidae and Isonychia) and the dominant stonefly (Perlesta placida) resulted in biomass peaks in winter – early spring. Caddisflies (mostly Hydropsychidae and Chimarra) and beetles (Elmidae and Gyrinidae) complemented the mayfly–stonefly pattern with highest values in late spring – summer. These seasonal patterns coincided with standing stock biomass patterns on submerged wood (snags), their preferred habitat. Drift values were about 5.7 times higher in the Ogeechee than in another Coastal Plain river having only one fifth the amount of snags, suggesting a relationship between habitat abundance and drift. Percentages of snag-dwelling insects found in drift were substantially higher (0.1 to > 1%) than is generally found for smaller streams, indicating drift distances and times much greater than previously shown.

Long-term effects of resource limitation on stream invertebrate drift

2001 ◽  
Vol 58 (8) ◽  
pp. 1624-1637 ◽  
Author(s):  
Edward R Siler ◽  
J Bruce Wallace ◽  
S L Eggert
Keyword(s):  
Woody Debris ◽  
Resource Limitation ◽  
Benthic Invertebrate ◽  
Invertebrate Drift ◽  
Total Biomass ◽  
Long Term Effects ◽  
Western North Carolina ◽  
Invertebrate Abundance ◽  
Reference Stream ◽  
Small Woody Debris

We examined the effects of resource limitation on stream invertebrate drift by reducing inputs of terrestrial detritus to a headwater stream in western North Carolina. In the treatment stream, leaf-litter was excluded for 6 years (September 1993 – August 1999), small woody debris was removed for 2 years (September 1996 – August 1998), and large and small woody debris was removed for 1 year (September 1998 – August 1999). Invertebrate abundance in the drift was significantly lower in the treatment stream during the study, but total biomass of invertebrate drift was similar. Although drift densities were higher in the reference stream, a greater proportion of total benthic invertebrate abundance and biomass drifted out of the treatment stream. The proportion of shredder, gatherer, and predator benthic abundance in the drift was significantly greater in the treatment stream, but scraper proportions were higher in the reference stream and filterer proportions were similar for the two streams. Combined data from both streams indicated that the relationship between drift densities and benthic abundance was positive and significant. Our results demonstrate that bottom-up effects of resource reduction in a detrital-based stream influence invertebrate drift, increasing the proportion of the benthic community emigrating from the detritus-poor stream.

scholarly journals Stable Isotope Analysis and Persistent Organic Pollutants in Crustacean Zooplankton: The Role of Size and Seasonality

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1490 ◽  
Author(s):  
Roberta Piscia ◽  
Michela Mazzoni ◽  
Roberta Bettinetti ◽  
Rossana Caroni ◽  
Davide Cicala ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Standing Stock ◽  
Fish Predation ◽  
Crustacean Zooplankton ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Pollutant Concentrations ◽  
Stock Biomass

Zooplankton is crucial for the transfer of matter, energy, and pollutants through aquatic food webs. Primary and secondary consumers contribute to the abundance and standing stock biomass, which both vary seasonally. By means of taxa- and size-specific carbon and nitrogen stable isotope analysis, the path of pollutants through zooplankton is traced and seasonal changes are addressed, in an effort to understand pollutant dynamics in the pelagic food web. We analyzed zooplankton plurennial changes in concentration of polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane and its relatives (DDTs) and in taxa-specific δ15N signatures in two size fractions, ≥450 µm and ≥850 µm, representative of the major part of zooplankton standing stock biomass and of the fraction to which fish predation is mainly directed, respectively. Our work is aimed at verifying: (1) A link between nitrogen isotopic signatures and pollutant concentrations; (2) the predominance of size versus seasonality for concentration of pollutants; and (3) the contribution of secondary versus primary consumers to carbon and nitrogen isotopic signatures. We found a prevalence of seasonality versus size in pollutant concentrations and isotopic signatures. The taxa-specific δ15N results correlated to pollutant concentrations, by means of taxa contribution to standing stock biomass and δ15N isotopic signatures. This is a step forward to understanding the taxa-specific role in pollutant transfer to planktivores and of zooplankton enrichment in PCBs and DDTs.

Macrobenthic community structure in tropical estuaries: the effect of sieve mesh-size and sampling depth on estimated abundance, biomass and composition

2013 ◽  
Vol 93 (6) ◽  
pp. 1441-1456 ◽  
Author(s):  
Ana Paula Maria Cavalcanti Valença ◽  
Paulo Jorge Parreira dos Santos
Keyword(s):  
Community Structure ◽  
Mesh Size ◽  
Environmental Parameters ◽  
Total Biomass ◽  
Sampling Depth ◽  
Total N ◽  
The Status ◽  
Sieve Mesh Size ◽  
The Difference ◽  
Sampling Procedures

Macrobenthic data from estuaries along the Pernambuco coast in north-eastern Brazil were analysed to evaluate the effect of sieve mesh size (1.0 mm × 0.5 mm) and sampling depth (0–10 cm × 0–20 cm) on the description of infaunal communities, in an attempt to discuss standardized sampling procedures for different ecological studies objectives in these ecosystems. In general, the difference in sieve retention was less evident for biomass but was important for abundance: the 1.0 mm sieve retained only 27% of total individuals but 77% of total biomass. Regarding sampling depth, the 0–10 cm layer contained most individuals (94%) but contributed just 64% of the overall biomass. Although no strong differences in community structure were observed at most sites with the use of different sieves, the correlations among community dissimilarity using different meshes with environmental parameters (organic matter, total-N and microphytobenthos) indicated that the use of the 0.5 mm sieve will allow a better evaluation of the status of these estuaries. The results also highlight the importance of taking the vertical distribution of tropical macrofauna into account for quantitative estimates: for taxa composition and abundance the top layer is clearly essential, whereas for biomass the deeper layers should also be considered.

scholarly journals Spatial autocorrelation of phytoplankton biomass is weak in the rivers of Lake Taihu Basin, China

2019 ◽  
pp. 35
Author(s):  
Zhaoshi Wu ◽  
Ming Kong ◽  
Yamin Fan ◽  
Xiaolong Wang ◽  
Kuanyi Li
Keyword(s):  
Community Structure ◽  
Spatial Autocorrelation ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Lake Taihu ◽  
Total Biomass ◽  
Phytoplankton Community Structure ◽  
River Systems ◽  
Toxic Cyanobacteria ◽  
The Mean

We investigated the characteristic of phytoplankton community structure across the entire Lake Taihu Basin (LTB), one of the most developed areas in China. A morphologically based functional group (MBFG) proposed by Kruk et al. (2010), especially potential toxic cyanobacteria (group III and VII), was also illustrated. Samples were collected at 96 sites along main rivers throughout the four seasons from September 2014 to January 2016. Significant differences in the phytoplankton community structure were observed at spatial (particularly between Huangpu/Tiaoxi and the other 4 river systems) and seasonal scales. On a spatial basis, high variability was observed in the mean phytoplankton biomass, with a relatively high value of 3.13 mg L−1 in Yanjiang system and a relatively low value in Huangpu (1.23 mg L−1) and Tiaoxi (1.44 mg L−1) systems. The mean biomass of potential toxic cyanobacteria accounted for 18.28% of the mean total biomass spatially, which was more abundant in Nanhe and Yanjiang systems. Spatial autocorrelation was weak for the total biomass and its four main components (bacillariophyta, chlorophyta, euglenophyta, and cyanobacteria) at whole basin scale regardless of season. Regarding the river system, significant autocorrelation was scarcely observed in all the river systems except Huangpu, especially in the inflows. The characteristic in terms of hydrological and environmental conditions may determine the community structure of the 6 river systems. Our study highlighted the importance of monitoring based on a large spatial scale, and more attention should be paid to potential toxic cyanobacteria for water quality management purposes.

Effects of forestry activities (clearfelling) on stream macroinvertebrate fauna in south-western Australia

1994 ◽  
Vol 45 (6) ◽  
pp. 963 ◽  
Author(s):  
IO Growns ◽  
JA Davis
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Western Australia ◽  
Macroinvertebrate Community ◽  
Total Abundance ◽  
Inorganic Solids ◽  
South West ◽  
Before And After ◽  
Stream Macroinvertebrate ◽  
Macroinvertebrate Fauna

The effects of forestry activities on macroinvertebrate community structure were examined in the headwaters of Carey Brook in the south-west of Australia. The fauna at four sites on an upland stream that ran through a logging coupe were compared, before and after clearfelling, with the fauna at four nearby undisturbed sites. Mean species richness and mean total abundance declined at the treatment sites relative to the control sites after the commencement of clearfelling activities. The composition of the macroinvertebrate fauna in the disturbed stream changed in comparison with that in the undisturbed sites after logging started but returned to the pre-logging composition after winter and spring rains had stopped. The observed changes in the macroinvertebrate fauna occurred during the periods of high loads of suspended inorganic solids at the treatment sites. The possible reasons for the observed results are discussed.

scholarly journals The influence of eutrophication and population biomass on common whitefish (Coregonus lavaretus) growth — the Lake Constance example revisited

2007 ◽  
Vol 64 (3) ◽  
pp. 402-410 ◽  
Author(s):  
Gregor Thomas ◽  
Reiner Eckmann
Keyword(s):  
Linear Regression Analysis ◽  
Standing Stock ◽  
Nutrient Content ◽  
Multiple Linear Regression Analysis ◽  
Lake Constance ◽  
Coregonus Lavaretus ◽  
Density Dependent ◽  
Stock Biomass ◽  
Evolutionary Response ◽  
The Impact

Accelerated growth of freshwater fish during anthropogenic eutrophication has been attributed almost exclusively to the increased nutrient content, while density-dependent effects have been largely neglected. We evaluated the relative importance of these factors by studying the growth of 43 consecutive year classes of common whitefish (Coregonus lavaretus) from Upper Lake Constance. This prealpine lake underwent eutrophication from the 1950s to 1970s, followed by reoligotrophication. Because whitefish are harvested with gill nets in a strongly size-selective way, we used back-calculated lengths of average fast-growing fish to compare growth among cohorts. Standing stock biomass was estimated based upon virtual year-class strengths. Multiple linear regression analysis revealed that growth of whitefish during their second year was most strongly related to standing stock biomass followed by PO4-P content during spring turnover and by calendar year, which was incorporated as a third independent variable (adjusted R2 = 0.84). The negative correlation between whitefish growth rate and calendar year is interpreted as evidence of an evolutionary response to the highly size-selective fishery during at least four decades. We conclude that density-dependent effects on whitefish growth are more important than had been realized previously and that the impact of eutrophication on growth of whitefish needs to be reconsidered.

Dipteran standing stock biomass and effects of aquatic bird predation at a constructed wetland

Wetlands ◽  
2000 ◽  
Vol 20 (1) ◽  
pp. 84-90 ◽  
Author(s):  
Michael C. Ashley ◽  
Julie A. Robinson ◽  
Lewis W. Oring ◽  
Gary A. Vinyard
Keyword(s):  
Constructed Wetland ◽  
Standing Stock ◽  
Aquatic Bird ◽  
Bird Predation ◽  
Stock Biomass
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