Ecological impact of Eurasian beaver (Castor fiber) activity on macroinvertebrate communities in Lithuanian trout streams

2012 ◽  
Vol 7 (1) ◽  
pp. 101-114 ◽  
Author(s):  
Virginija Pliūraitė ◽  
Vytautas Kesminas
Keyword(s):  
Relative Abundance ◽  
Ecological Impact ◽  
Macroinvertebrate Communities ◽  
Beaver Pond ◽  
Absolute Abundance ◽  
Habitat Types ◽  
Percentage Composition ◽  
Beaver Ponds ◽  
Eurasian Beaver ◽  
The Absolute

AbstractOur study found that beaver activity affects macroinvertebrate assemblages of both beaver ponds and downstream sites. The percentage composition of the invertebrate faunae of beaver ponds was strikingly different from the invertebrate faunae of upstream forested and downstream sites. The number of EPT (ephemeropteran, plecopteran, trichopteran) taxa in the upstream forested sites in all streams was higher than in beaver pond and downstream sites. Statistically significant differences were found in absolute and relative abundances of EPT and Chironomidae between different streams sites. The absolute and relative abundance of pollution-sensitive EPT was significantly higher in forested sites than in beaver pond and downstream sites in all measured streams. Beaver ponds had a significantly higher absolute and relative abundance of Chironomidae compared with upstream forested and downstream sites. We found that Plecoptera and Coleoptera were absent from beaver pond sites. The absolute abundance of Plecoptera was significantly higher in upstream forested sites than in downstream sites in all three streams. Gatherers were the dominant functional feeding group in relative abundance in all three habitat types. The percentage of gatherers was higher in beaver ponds than in forested and downstream sites.

scholarly journals Contemporary fisheries stock assessment: many issues still remain

2014 ◽  
Vol 72 (1) ◽  
pp. 7-18 ◽  
Author(s):  
Mark N. Maunder ◽  
Kevin R. Piner
Keyword(s):  
Information Content ◽  
Relative Abundance ◽  
Stock Assessment ◽  
Diagnostic Methods ◽  
Natural Mortality ◽  
Absolute Abundance ◽  
Substantial Impact ◽  
Composition Data ◽  
The Absolute ◽  
Management Advice

Abstract Interpretation of data used in fisheries assessment and management requires knowledge of population (e.g. growth, natural mortality, and recruitment), fisheries (e.g. selectivity), and sampling processes. Without this knowledge, assumptions need to be made, either implicitly or explicitly based on the methods used. Incorrect assumptions can have a substantial impact on stock assessment results and management advice. Unfortunately, there is a lack of understanding of these processes for most, if not all, stocks and even for processes that have traditionally been assumed to be well understood (e.g. growth and selectivity). We use information content of typical fisheries data that is informative about absolute abundance to illustrate some of the main issues in fisheries stock assessment. We concentrate on information about absolute abundance from indices of relative abundance combined with catch, and age and length-composition data and how the information depends on knowledge of population, fishing, and sampling processes. We also illustrate two recently developed diagnostic methods that can be used to evaluate the absolute abundance information content of the data. Finally, we discuss some of the reasons for the slowness of progress in fisheries stock assessment.

scholarly journals A multi-view model for relative and absolute microbial abundances

2019 ◽  
Author(s):  
Brian D. Williamson ◽  
James P. Hughes ◽  
Amy D. Willis
Keyword(s):  
Relative Abundance ◽  
Estimation Error ◽  
Bacterial Species ◽  
Critical Role ◽  
Sensitivity Study ◽  
Universal Primers ◽  
Rrna Gene ◽  
Absolute Abundance ◽  
Abundance Data ◽  
The Absolute

AbstractThe absolute abundance of bacterial taxa in human host-associated environments play a critical role in reproductive and gastrointestinal health. However, obtaining the absolute abundance of many bacterial species is typically prohibitively expensive. In contrast, relative abundance data for many species is comparatively cheap and easy to collect (e.g., with universal primers for the 16S rRNA gene). In this paper, we propose a method to jointly model relative abundance data for many taxa and absolute abundance data for a subset of taxa. Our method provides point and interval estimates for the absolute abundance of all taxa. Crucially, our proposal accounts for differences in the efficiency of taxon detection in the relative and absolute abundance data. We show that modeling taxon-specific efficiencies substantially reduces the estimation error for absolute abundance, and controls the coverage of interval estimators. We demonstrate the performance of our proposed method via a simulation study, a sensitivity study where we jackknife the taxa with observed absolute abundances, and a study of women with bacterial vaginosis.

Abundance of Boeckella gracilis (Daday, 1902) (Copepoda, Calanoida) in seasonal coastal pools in the Araucania region (38°S, Chile)

Crustaceana ◽  
2018 ◽  
Vol 91 (10) ◽  
pp. 1211-1217
Author(s):  
Patricio De los Ríos
Keyword(s):  
Correlation Analysis ◽  
Environmental Stress ◽  
Relative Abundance ◽  
Calanoid Copepod ◽  
Inverse Correlation ◽  
Inland Waters ◽  
Absolute Abundance ◽  
Significant Inverse Correlation

Abstract The presence of the calanoid copepod Boeckella gracilis (Daday, 1902) in Chilean seasonal pools has been only poorly studied as yet. The aim of the present study thus is to investigate the role of conductivity and temperature on the relative and absolute abundance of B. gracilis in seasonal coastal pools in the Araucania region (38°S, Chile). The results of correlation analysis revealed the presence of a significant inverse correlation between conductivity and relative abundance, whereas no significant correlations were found between conductivity and absolute abundance, between temperature and absolute abundance, and between temperature and relative abundance. These results agree partially with similar observations for mountain pools in the same region, but they would not agree with observations for calanoids of saline and subsaline inland waters in the northern and southern extremes of Chile. Considering this scenario, the species would show different populational responses to environmental stress in different situations, which phenomenon deserves to be studied more extensively and in more detail.

scholarly journals Paleoenvironmental and paleobiological origins of coccolithophorid genusWatznaueriaemergence during the late Aalenian–early Bajocian

Paleobiology ◽  
2015 ◽  
Vol 41 (3) ◽  
pp. 415-435 ◽  
Author(s):  
Baptiste Suchéras-Marx ◽  
Emanuela Mattioli ◽  
Fabienne Giraud ◽  
Gilles Escarguel
Keyword(s):  
Marine Invertebrate ◽  
Time Interval ◽  
Calcareous Nannofossils ◽  
Calcareous Nannoplankton ◽  
Absolute Abundance ◽  
The Pacific ◽  
Relative Abundances ◽  
The Absolute ◽  
Oceanic Plates ◽  
Central Atlantic

AbstractThe latest Aalenian–early Bajocian time interval (ca. 171-169 Ma) is marked by a global reorganization of oceanic plates with the Central Atlantic opening and the formation of the Pacific plate. This time interval is also marked by a global geochemical perturbation of δ13C with a negative excursion at the Aalenian/Bajocian boundary and a positive excursion during the early Bajocian. Evolutionary diversifications of marine invertebrate taxa, namely ammonites, radiolarians, and coccolithophorids, are recorded at that time. Concerning coccolithophorids, this interval witnesses the diversification and expansion of the most successful Mesozoic genus:Watznaueria. In this study, we explore the potential environmental, ecological, and biological forcing at the origin ofWatznaueriadiversification and its effect on the coccolith assemblages through quantification of the absolute and relative abundances of calcareous nannofossils in two Middle Jurassic key sections: Cabo Mondego (Portugal) and Chaudon-Norante (France). In both sections, we find an increase in nannofossil absolute abundance and flux at the beginning of the lower Bajocian, coeval with an increase in absolute and relative abundances ofWatznaueriaspp., followed by a plateau in the middle and upper part of the lower Bajocian. The increase ofWatznaueriaspp. is synchronous with a decrease in relative abundance of other major coccolith taxa, whereas the absolute abundance of these species did not decrease. During the climatically driven early Bajocian eutrophication event,Watznaueriaspp. integrated into the calcareous nannoplankton community in two successive evolutionary steps involving firstW. contractaandW. colaccicchii, and secondW. britannicaandW.aff.manivitiae. Step 1 was driven by an increase in niche carrying capacities linked to the early Bajocian eutrophication. Step 2 was driven by specific adaptation of the newly evolvedWatznaueriaspecies to bloom in nutrient-rich environments not exploited before. These evolutionary events have initiated the 100-Myr reign ofWatznaueriaover the calcareous nannoplankton community.

scholarly journals Biodiversity of Sulfate Reducing Bacteria in Mercury-Contaminated Beaver Ponds at Avery Brook

2014 ◽  
Vol 3 (1) ◽  
pp. 13-17
Author(s):  
Rachel Anne Kaminsky ◽  
Sara Sirois ◽  
Robert Merritt ◽  
Laura Katz
Keyword(s):  
Sulfate Reducing Bacteria ◽  
Water Interface ◽  
Beaver Pond ◽  
Clone Libraries ◽  
Beaver Ponds ◽  
Sulfate Reducing ◽  
Biogeographic Pattern ◽  
Stream System ◽  
Favorable Conditions ◽  
Reducing Bacteria

Beaver ponds act as mercury sinks, exhibiting favorable conditions for the production of neurotoxic methylmercury by sulfate reducing bacteria (SRBs), a group of bacteria that are characterized by function (sulfate reduction) rather than phylogeny.  This study was conducted to explore the diversity of SRB communities inhabiting microenvironments at the sediment-water interface in one beaver pond located on the Avery Brook stream system in the Conway State Forest.  Clone libraries were constructed in order to capture some of the diversity of sulfate-reducing bacteria as well as a biogeographic pattern.  Though the clone libraries did not reveal a biogeographic pattern, the results showed an unprecedented amount of SRB diversity in all sampled microenvironments.

Response of benthic macroinvertebrate communities to El Niño related drought events in six upland streams in south-central Ontario

2008 ◽  
Vol 65 (5) ◽  
pp. 890-905 ◽  
Author(s):  
Beth Gilbert ◽  
Peter J Dillon ◽  
Keith M Somers ◽  
Ron A Reid ◽  
Lem Scott
Keyword(s):  
Relative Abundance ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
South Central ◽  
Effects Of Drought ◽  
One Year ◽  
The Impact

We examined the effects of extreme drought events on benthic macroinvertebrate (BMI) community structure in six forested upland streams in south-central Ontario, Canada, during a 9-year period. Variation in the mean winter El Niño – Southern Oscillation Index was strongly correlated with drought conditions (zero flow days) in the study streams. Drought onset and duration varied among study streams and among years. Below-average precipitation coincided with the occurrence of drought, although it remains unclear if snowfall and rainfall contributed equally to the impact of decreased precipitation. Increased relative abundance of Ephemeroptera, Plecoptera, and Trichoptera (EPT) one year following drought and decreased relative abundance two years after drought indicated high resistance but poor resilience. In contrast, chironomids showed poor resistance and high resilience. Although these patterns were not consistent across all streams, temporal coherence among streams was found in percent EPT, percent chironomids, and percent dipterans, suggesting that drought acts as a disturbance mechanism that simplifies benthos community assemblages. Biocriteria developed from 22 nearby reference streams indicated that abnormal BMI communities occurred only after recurring episodes of drought, indicating that the effects of drought are cumulative. Headwater streams may prove to be sentinel ecosystems for monitoring the impacts of climate change.

scholarly journals Distribusi dan Kemelimpahan Meiofauna di Hulu Sungai Code Yogyakarta

2012 ◽  
Vol 9 (2) ◽  
pp. 34 ◽  
Author(s):  
Riche - Hariyati
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
River Water ◽  
Relative Abundance ◽  
Horizontal Distribution ◽  
Water Current ◽  
Habitat Types ◽  
Chemical Parameter ◽  
Physico Chemical

This research is aimed to study distribution and abundance of meiofauna and the quality of physicochemicalcharacteristics of uppersite of code river and up stream river code Yogyakarta province. Samples weretaken using modified Pysto style corer and were located based on habitat types specific river, which are pool, riffle,rapid, left side and right side of water column. Sample taken four times for each zone. The parameter of for waterquality measured were dissolved oxygen. Water current, alkalinity and pHResult from the analysis showed that the abundance of meiofauna at code river the highest at left side zone.Which was 537.806 individu/m3 with relative abundance was 28,09% result from physico chemical parameter ofdissolved oxygenbetween 5,44 ppm – 6,0 ppm, alkalinity 20 ppm – 25 ppm , pH 7,10 – 7,18.and watercurrenntmeasured between 0,03 m/sec – 0,49 m/sec. The abundance of meiofauna at code river was dominated bygroup of Nematodes horizontal distribution of the fauna was the widest for Nematodes ostracoda, Rhizopoda andinsecta. Physico chemicalquality of code river water was relative good for meiofauna habitat and other waterorganisms

On the absolute abundance of calcium in solar flares

1993 ◽  
Vol 404 ◽  
pp. 394 ◽  
Author(s):  
Alphonse C. Sterling ◽  
George A. Doschek ◽  
Uri Feldman
Keyword(s):  
Solar Flares ◽  
Absolute Abundance ◽  
The Absolute

Corrigendum to: Distribution and relative abundance of forest duikers in Dassioko Sud Forest Reserve (coastal Côte d'Ivoire)

2018 ◽  
Vol 45 (2) ◽  
pp. 194
Author(s):  
K. A. Yao ◽  
E. A. Bitty ◽  
K. B. Kassé ◽  
Y. C. Kouakou ◽  
K. H. Yaokokoré-Beibro ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Habitat Preferences ◽  
Habitat Type ◽  
Distribution Patterns ◽  
Encounter Rate ◽  
Line Transect ◽  
Habitat Types ◽  
Anthropogenic Pressures ◽  
Forest Reserve ◽  
Encounter Rates

Context Duikers play a vital role in maintaining forest ecosystems, as both seed dispersers and prey. In West Africa, duikers are also an important source of food and income; however, it is likely that some species are now being hunted at unsustainable levels. So as to contribute to duiker conservation, we used line-transect data and additional information on dung and track counts to estimate relative abundance and establish distribution patterns of forest duikers in Côte d'Ivoire's Dassioko Sud Forest Reserve (DSFR), a poorly known, remnant coastal rainforest. We also collected basic information on hunting pressure. Methods Forest duiker counts were made twice per month from July 2013 to March 2014 on six line transects of varying lengths (5.6–6.7km) and in different regions of the DSFR, representing different habitat types. The number of sightings per kilometre walked, defined as ‘encounter rate', was used to compute an index of relative abundance. We recorded all evidence of poachers and used these data to generate a poaching index (# poaching signs per kilometre) for different habitat types. Key results The DSFR has lost three of seven total forest duiker species and populations of the four remaining species are declining. Encounter rates were greatest for Philantomba maxwellii (0.46 indices km–1) and accounted for 68% of total encounters. Cephalophus niger, C. dorsalis and C. silvicultor were encountered at similar (0.07 indices km–1) but much lower rates. For all species, mean encounter rates were highest in degraded forest (0.38–0.73 indices km–1), followed by secondary (0.2–0.44 indices km–1) and primary (0.19–0.44 indices km–1) forest. Conclusions Of the four forest duiker species still present in the DSFR, the black, bay and yellow-backed duikers are the most affected by anthropogenic pressures. Duiker abundance in the DSFR varies with habitat type. This variation is apparently influenced by differences in forest structure, poaching pressure and proximity to villages. Implications The study provides baseline data for future managing of ungulate populations in the DSFR. We recommend that a biomonitoring study of duiker populations be initiated immediately to help determine population trends, investigate habitat preferences, and help curb illegal hunting activities in this important forest reserve.

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