Academic literature on the topic 'Percentage abundance'
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Journal articles on the topic "Percentage abundance"
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Zhao, Jie, and Deborah A. Neher. "Soil energy pathways of different ecosystems using nematode trophic group analysis: a meta analysis." Nematology 16, no. 4 (2014): 379–85. http://dx.doi.org/10.1163/15685411-00002771.
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We analysed 67 raw data sets of nematode genera from three types of ecosystems (grassland, cropland, and forest) to compare relative magnitude of energy pathways through the soil food web. Bacterial-, fungal- and herbivorous-based energy pathways were compared by percentages (in either abundances or biomass) of three soil nematode trophic groups (i.e., bacterivore, fungivore and herbivore). The patterns of soil energy pathways were similar whether expressed as relative abundance or relative biomass. However, the percentage values of bacterivorous biomass in each type of ecosystem exceeded the percentage values of their abundance. Specifically, relative abundance of bacterivorous nematodes was similar among ecosystems but mean values of biomass were greatest in grassland and similarly less in cropland and forest ecosystems. By contrast, both relative abundance and biomass of fungivorous nematodes decreased progressively from forest to cropland and grassland ecosystems. The opposite pattern across ecosystems was observed for both relative abundance and biomass of herbivorous nematodes. We conclude that energy pathways are bacterial-dominated in all of the ecosystems whether expressed as abundance or biomass. Fungal and herbivorous pathways are second in dominance in forest and grassland ecosystems, respectively. The relative size of the fungal-based energy pathway suggests a gradient of resource quality among ecosystems. We suggest that herbivorous-based energy pathways are more important in grassland ecosystems than reported previously.
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Kim, Dongun, Janet D. Klein, Sandy Racine, Brian P. Murrell, and Jeff M. Sands. "Urea may regulate urea transporter protein abundance during osmotic diuresis." American Journal of Physiology-Renal Physiology 288, no. 1 (2005): F188—F197. http://dx.doi.org/10.1152/ajprenal.00200.2004.
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Rats with diabetes mellitus have an increase in UT-A1 urea transporter protein abundance and absolute urea excretion, but the relative amount (percentage) of urea in total urinary solute is actually decreased due to the marked glucosuria. Urea-specific signaling pathways have been identified in mIMCD3 cells and renal medulla, suggesting the possibility that changes in the percentage or concentration of urea could be a factor that regulates UT-A1 abundance. In this study, we tested the hypothesis that an increase in a urinary solute other than urea would increase UT-A1 abundance, similar to diabetes mellitus, whereas an increase in urine urea would not. In both inner medullary base and tip, UT-A1 protein abundance increased during NaCl- or glucose-induced osmotic diuresis but not during urea-induced osmotic diuresis. Next, rats undergoing NaCl or glucose diuresis were given supplemental urea to increase the percentage of urine urea to control values. UT-A1 abundance did not increase in these urea-supplemented rats compared with control rats. Additionally, both UT-A2 and UT-B protein abundances in the outer medulla increased during urea-induced osmotic diuresis but not in NaCl or glucose diuresis. We conclude that during osmotic diuresis, UT-A1 abundance increases when the percentage of urea in total urinary solute is low and UT-A2 and UT-B abundances increase when the urea concentration in the medullary interstitium is high. These findings suggest that a reduction in urine or interstitial urea results in an increase in UT-A1 protein abundance in an attempt to restore inner medullary interstitial urea and preserve urine-concentrating ability.
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Kriz, James C., Stephen D. Danielson, James R. Brandle, Erin E. Blankenship, and Geoff M. Henebry. "Effects of Aphid (Homoptera) Abundance and Surrounding Vegetation on the Encounter Rate of Coccinellidae (Coleoptera), Chrysopidae (Neuroptera), and Nabidae (Hemiptera) in Alfalfa." Journal of Entomological Science 41, no. 3 (2006): 211–20. http://dx.doi.org/10.18474/0749-8004-41.3.211.
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Predaceous insect encounter rate was measured in 21 southeast Nebraska alfalfa fields through weekly sweep net sampling during 2002–03. The most frequently encountered predaceous insect families were Coccinellidae (Coleoptera), Nabidae (Hemiptera), and Chrysopidae (Neuroptera). The study used multiple regression analysis to examine the effect of aphid abundance and the surrounding vegetative patch composition on predaceous insect abundance. In 2002, Hippodamia parenthesis Say was encountered more frequently in fields with lower aphid abundances, and Hippodamia convergens Guerin-Meneville, Coccinella septem-punctata L., and Nabis americoferus Carayon were encountered more frequently in fields with higher aphid abundances. In 2003, Coleomegilla maculata DeGeer was encountered more frequently in fields with higher aphid abundance. The remaining two species of coccinellids and Chryoperla spp. did not exhibit significant correlations with aphid abundance in either year. It was determined that in 2002, H. parenthesis was encountered more frequently in alfalfa surrounded by a higher percentage of unfarmed land, and C. maculata, C. septempunctata, N. americoferus, and Chrysoperla spp. were encountered more frequently in alfalfa surrounded by a higher percentage of farmed land. In 2003, N. americoferus was again encountered more frequently in alfalfa fields surrounded by a higher percentage of farmed land. The remaining three coccinellid species collected did not exhibit significant relationships between vegetative patch composition and encounter rate in either year.
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Piovesan, Paulo Ricardo Rodrigues, José Luís Campana Camargo, Robyn Jeanette Burnham, and Isolde Dorothea Kossmann Ferraz. "Abundance of liana species in an Amazonian forest of Brazil reflects neither adventitious root nor foliar sprout production." Journal of Tropical Ecology 34, no. 4 (2018): 257–67. http://dx.doi.org/10.1017/s0266467418000238.
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Abstract:Liana abundance and size have increased in neotropical forests. High vegetative reproductive capacity (clonality) may be the cause of high abundance in some liana species. Correlations between vegetative propagation capacity and (1) relative abundance of liana species, (2) rooting and foliar sprouting potentials of congeneric species, and (3) phylogenetic position were determined. Species selection was based on the relative abundance of lianas in ten 0.5-ha parcels in continuous forest within the Biological Dynamics of Forest Fragments Project (BDFFP), Brazil. Five individuals per species were replicated with seven cuttings per individual. Cuttings placed in moistened sand and coconut fibre were observed for 5 mo in a humid greenhouse. Survival percentage, rooting percentage, potential regeneration index and longest root length were determined per species. The two most abundant species (9.3% and 4.1% relative abundance) had low vegetative regeneration capacity, contrary to expectations. However, a significant, positive relationship between vegetative propagation and relative abundance of liana species whose relative abundances were <4% was found. Congeneric species showed no difference in vegetative propagation between rare and abundant species, except congeners of Machaerium. Vegetative reproductive capacity occurred in all major evolutionary lineages, but was highest in Fabaceae and Bignoniaceae, families of high abundance both locally and broadly across Neotropical forests.
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Usman, Rilwan Loko, Umar Ibrahim, Samson Dauda Yusuf, Idris Muhammad Mustapha, Emmanuel Ifeanyi Ugwu, and Olatunji Samuel Ayanninuola. "Identification of Medical and Industrial Used Radioisotopes in Mining Sites of Nasarawa, Nasarawa State, Nigeria." Journal of Oncology Research 4, no. 1 (2022): 27. http://dx.doi.org/10.30564/jor.v4i1.3635.
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This research intends to unveil the presence of radioisotopes in the soil of some mining sites in Nasarawa of Nasarawa state using thermos-scientific interceptor (IdentiFINDER). The work aimed at detecting the presence, types and trust level of radioisotopes. The result showed that, 103Pd and 125I were found in 57% of the total points and the percentage abundance of the detector reached 50-65% indicating that, those radioisotopes are likely found in the area, 109Cd was found in 15% of the total areas. The percentage abundance of the detector for 109Cd shows 50% indicating that, those radioisotopes are likely to be found in the area, 241Am was found in 7% of the total areas. The percentage abundance of the detector for 241Am shows 81% indicating that, those radioisotopes are likely found in the area, 235U was found in 7% of the total points. The percentage abundance of the detector for 235U reaches 57% indicating that, those radioisotopes are likely found in the area, 75Se was found in 7% of the total points. The percentage abundance of the detector for 75Se was in abundance up to 57% indicating that, those radioisotopes are likely gotten in the area and 57Co was gotten in 7% of the total areas. The percentage abundance of the detector for 57Co was 54% indicating that, those radioisotopes are likely to be gotten in the area. Based on this high percentage abundance of the detector for these radioisotopes, they can be harnessed and applied appropriately in medicine and industry.
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Paul, C. R. "Milankovitch cycles and microfossils: principles and practice of palaeoecological analysis illustrated by Cenomanian chalk-marl Rhythms." Journal of Micropalaeontology 11, no. 1 (1992): 95–105. http://dx.doi.org/10.1144/jm.11.1.95.
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Abstract. While standardization of sampling, processing and picking techniques is essential in micropalaeontology, standard counts (and percentages) have three serious disadvantages. They are interdependent, so changes in one taxon affect counts of all others; they can be misleading, e.g. when percentage abundance increases but absolute numbers decrease; and they conceal changes in absolute abundance, which for palaeoecology are often most revealing. A technique which combines a minimum count with estimates of absolute numbers is recommended and has been applied to 12 samples from a mid-Cenomanian chalk/marl rhythm. Data for insoluble residues, stable isotopes of carbon and oxygen and numbers of planktonic and benthonic foraminifera and ostracods all vary through the rhythm. Absolute abundance of planktonic foraminifera correlates best with surface sea water temperatures calculated from oxygen isotopes. Abundances of both calcareous and agglutinated benthonic foraminifera correlate best with percent insoluble residue values and these foraminifera respond passively to changes in sedimentation rate. Ostracods do not correlate well with either control. Ratios of insoluble residues and of benthonic foraminiferal abundances between chalks and marls confirm that the rhythms are productivity cycles. Mid-Cenomanian chalk beds were deposited rapidly, taking at most 5–7000 years of the 21,000 year precession cycle.
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Pliūraitė, Virginija, and Vytautas Kesminas. "Ecological impact of Eurasian beaver (Castor fiber) activity on macroinvertebrate communities in Lithuanian trout streams." Open Life Sciences 7, no. 1 (2012): 101–14. http://dx.doi.org/10.2478/s11535-011-0084-y.
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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.
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Pastorelli, Roberta, Alessandro Paletto, Alessandro Elio Agnelli, Alessandra Lagomarsino, and Isabella De Meo. "Microbial Diversity and Ecosystem Functioning in Deadwood of Black Pine of a Temperate Forest." Forests 12, no. 10 (2021): 1418. http://dx.doi.org/10.3390/f12101418.
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The present study provides a deeper insight on variations of microbial abundance and community composition concerning specific environmental parameters related to deadwood decay, focusing on a mesocosm experiment conducted with deadwood samples from black pine of different decay classes. The chemical properties and microbial communities of deadwood changed over time. The total carbon percentage remained constant in the first stage of decomposition, showing a significant increase in the last decay class. The percentage of total nitrogen and the abundances of nifH harbouring bacteria significantly increased as decomposition advanced, suggesting N wood-enrichment by microbial N immobilization and/or N2-fixation. The pH slightly decreased during decomposition and significantly correlated with fungal abundance. CO2 production was higher in the last decay class 5 and positively correlated with bacterial abundance. Production of CH4 was registered in one sample of decay class 3, which correlates with the highest abundance of methanogenic archaea that probably belonged to Methanobrevibacter genus. N2O consumption increased along decomposition progress, indicating a complete reduction of nitrate compounds to N2 via denitrification, as proved by the highest nosZ gene copy number in decay class 5. Conversely, our results highlighted a low involvement of nitrifying communities in deadwood decomposition.
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Holuša, Jaroslav, Tomáš Fiala, and Jiří Foit. "Ambrosia Beetles Prefer Closed Canopies: A Case Study in Oak Forests in Central Europe." Forests 12, no. 9 (2021): 1223. http://dx.doi.org/10.3390/f12091223.
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Research Highlights: The percentage of canopy closure was found to be the main factor associated with ambrosia beetle abundance and species richness. The latter two variables increased as canopy closure increased, probably because a high percentage of canopy closure provides a stable and humid environment suitable for the growth of ambrosia fungi. Objectives: Oak is a common host tree for ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), which have independently evolved a nutritional mutualism with fungi. We suspected that ambrosia beetles might have specific habitat preferences that are different from those of other saproxylic beetles and that reflect the specific habitat preferences of their food, i.e., ambrosia fungi. Methods: We assessed ambrosia beetle abundance with ethanol-lured traps in five old-growth oak dominated forests and five managed oak dominated forests (one trap per forest) during the vegetation period in 2020. We determined whether ambrosia beetle abundance and species richness depend on forest type (managed vs. unmanaged), degree of canopy closure, abundance of oak trees, abundance of coarse deadwood, and abundance of dead oak branches. Results: In total, 4137 individuals of six species of ambrosia beetles associated with oaks were captured. The native ambrosia beetle Anisandrus dispar represented the majority of trapped ambrosia bark beetles. A. dispar along with another ambrosia beetle, Xyleborinus saxesenii, represented 99% of all captured beetles. Conclusions: In addition to canopy closure, the abundance of oak trees and the abundance of dead oak branches were significantly associated with ambrosia beetle abundance and species richness. The abundance of A. dispar was mainly correlated with dead oak branch abundance and the degree of canopy closure, whereas the abundances of X. saxesenii and of the invasive species Xyleborinus attenuatus and Cyclorhipidion bodoanum were mainly correlated with the net area occupied by oak trees.
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Timm, Henn, and Marina Haldna. "Do abundance and percentage of dipteran larvae and Oligochaeta indicate low water quality in streams and lake littoral?" Oceanological and Hydrobiological Studies 48, no. 4 (2019): 415–29. http://dx.doi.org/10.2478/ohs-2019-0036.
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Abstract The presence of chironomids and/or oligochaetes is generally considered to be an indication of poor status of freshwater. Non-chironomid dipterans show unclear trends. The abundance and percentage of these groups are rarely used as potential indicators. We attempted to determine whether these metrics reveal freshwater quality in lowland streams and lake littoral (Northern Europe, Baltic ecoregion, Estonia). The water quality was assessed based either on the water itself or on macroinvertebrates, fish, macrophytes, phytobenthos (in streams only) and/or phytoplankton (in lakes only). As expected, the high abundance and high percentage of chironomids and ceratopogonids indicated low quality of water in lakes. The high percentage of chironomids indicated low water quality also in streams. The high percentage of oligochaetes indicated low water quality in lakes. However, their high abundance (but not the percentage) was unexpectedly a symptom of high water quality in streams and to a lesser extent in lakes. In these cases, oligochaetes were represented by rheophilic, rather than saprophilic species. The abundance of simuliids (but not the percentage) and the richness of dipteran families indicated high water quality in streams. We suggest that the obtained results will allow better use of the indicative potential of freshwater macroinvertebrates.
Books on the topic "Percentage abundance"
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Berger, Robert H., Robyn J. Wahl, and M. Paul Chaplin. Formulary management/pharmacy and therapeutics committees. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199360574.003.0028.
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While the cost of health care rises in all public healthcare organizations, budgets for that care have remained the same or have decreased. This is most certainly true in correctional settings. Because pharmaceutical expenditures are a substantial percentage of a health care organization’s budget, medication utilization is closely scrutinized. Clinicians must consider the appropriateness, effectiveness, and safety of medications prescribed to incarcerated patients. The abundance of available drugs and the complex issues with respect to their safe and effective use make a sound program for maximizing rational drug use critical. This is a challenging task in jails and prisons that requires a reexamination of the treatments provided. This is not a process of arbitrarily limiting prescriber choices or their decision-making authority solely based on cost-saving incentives. Evidence-based, best practices that inform the development of, and adherence to, disease management guidelines and a preferred, restricted medication formulary enhances the quality, safety, and effectiveness of the care provided. This chapter details the process and procedures to develop, implement, and monitor prescription practice change by establishing an effective Pharmacy & Therapeutics Committee (P & TC). The chapter further addresses: the roles and responsibilities of a P & TC; P & TC decision-making processes; formulary development and modification; formulary process decision-making; medication therapy management guidelines; prescriber education; and data analytics to assist in monitoring outcomes, medication use, and prescriber adherence to P & TC policies.
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Mills, M. G. L., and M. E. J. Mills. Coexistence and the cheetah’s relations with other carnivores. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198712145.003.0009.
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In the southern Kalahari densities of large carnivores are relatively low, with the brown hyena the most abundant. Resource partitioning is well defined as each species tends to concentrate on the prey species it is best adapted to utilize, and they show dietary flexibility. Interactions between cheetahs and other large carnivores were rare and mostly inconsequential. Only 6.1% of kills were kleptoparasitized, with an average percentage loss of 65% per kill. Nearly all (82.6%) kills stolen, were stolen at night, were springbok, and the perpetrators were mainly lions and brown hyenas. Diurnal hunting largely counters kleptoparasitism, and anyway cheetahs are well adapted physiologically, through their daily energy expenditure, to cope with over 25% loss of kills. Jackals were often attracted to cheetah kills. Occasionally, if numbers grew to more than five, they could harass cheetahs into abandoning the kill prematurely. Jackals may also sometimes kill small cheetah cubs.
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Kirchman, David L. The ecology of viruses. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0010.
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In addition to grazing, another form of top-down control of microbes is lysis by viruses. Every organism in the biosphere is probably infected by at least one virus, but the most common viruses are thought to be those that infect bacteria. Viruses come in many varieties, but the simplest is a form of nucleic acid wrapped in a protein coat. The form of nucleic acid can be virtually any type of RNA or DNA, single or double stranded. Few viruses in nature can be identified by traditional methods because their hosts cannot be grown in the laboratory. Direct count methods have found that viruses are very abundant, being about ten-fold more abundant than bacteria, but the ratio of viruses to bacteria varies greatly. Viruses are thought to account for about 50% of bacterial mortality but the percentage varies from zero to 100%, depending on the environment and time. In addition to viruses of bacteria and cyanobacteria, microbial ecologists have examined viruses of algae and the possibility that viral lysis ends phytoplankton blooms. Viruses infecting fungi do not appear to lyse their host and are transmitted from one fungus to another without being released into the external environment. While viral lysis and grazing are both top-down controls on microbial growth, they differ in several crucial respects. Unlike grazers, which often completely oxidize prey organic material to carbon dioxide and inorganic nutrients, viral lysis releases the organic material from hosts more or less without modification. Perhaps even more important, viruses may facilitate the exchange of genetic material from one host to another. Metagenomic approaches have been used to explore viral diversity and the dynamics of virus communities in natural environments.
Book chapters on the topic "Percentage abundance"
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Salvadori, Justine, Rossella Varvara, and Richard Huyghe. "Chapter 4. Measuring affix rivalry as a gradient relationship." In Linguistik Aktuell/Linguistics Today. John Benjamins Publishing Company, 2024. http://dx.doi.org/10.1075/la.284.04sal.
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In many languages, affixes can be used to derive words with the same semantic types and can therefore compete in word formation. This paper discusses how to quantitatively assess the competition between derivational affixes based on their semantic similarity. Two possible measures of affix rivalry drawn from studies in ecology are examined: the Sørensen index, which considers the proportion of shared functions between rival affixes; and the Percentage similarity coefficient, which is based on the realization frequency of functions. Two complementary measures (Balanced richness and Balanced abundance) are also proposed to further analyze the semantic dissimilarity between rival affixes. Using the semantic competition between six French deverbal suffixes as a case study, we show how these four measures suit the quantification of affix rivalry and help capture different aspects of the phenomenon.
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Shanmugam, Indumathi, Kamali Kandhasam, Jagadeesan Ramasamy, Anburaj Raj, Prabu Periasamy, and Lakshmanan Ramkumar. "Phyto-Assisted Synthesis of Silver Nanoparticles for Effectively Combating Toxin-Producing Fungi in Poultry Feed." In Therapeutic Plants: Recent Advances in the Use of Herbs as Alternative Medications. BENTHAM SCIENCE PUBLISHERS, 2025. https://doi.org/10.2174/9789815322910125010018.
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The present study aimed to investigate Carica papaya-mediated silver nanoparticle synthesis and its role in mitigating aflatoxigenic fungi isolated from poultry feed. Proximate analysis of the feed samples revealed their moisture content, crude protein percentage, and crude fat percentage. Fungal isolates were enumerated, and their abundance and frequency were determined. Toxin production by A. flavus isolates, which contributes about 33%, was assessed by PCR amplification targeting specific genes associated with aflatoxin production. Phytochemical analysis was conducted on different plant extracts, and the presence of various compounds was determined. Silver nanoparticles were synthesized using Carica papaya, and their characterization was performed using various techniques, including UV-Spectroscopy, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Finally, the antifungal activity of the Carica papaya extract and silver nanoparticles was evaluated against aflatoxigenic fungi in which the AgNPs showed greater inhibition value between 10 mm and 22 mm. These findings contribute to the understanding that silver nanoparticles may significantly inhibit the growth of aflatoxigenic fungi isolated from poultry feed.
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O’Dowd, Alison P., Anna P. Solverson, and Anne Chin. "Ecological response of step-pool streams to wildfire in the Front Range of Colorado (USA)." In Biogeomorphic Responses to Wildfire in Fluvial Ecosystems. Geological Society of America, 2024. http://dx.doi.org/10.1130/2024.2562(05).
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ABSTRACT Wildfire affects ecosystems via the disruption of landforms and biota. Step and pool formations in mountainous streams have important hydraulic and ecological functions, but there is little information on wildfire impacts on step‐pool ecosystems. This chapter describes a study examining the biophysical responses of headwater mountain streams for 2 years following the 2012 Waldo Canyon Fire in Pike National Forest (Front Range of Colorado, USA). We focused on the impacts of this wildfire on stream invertebrate communities, including richness, composition, and traits related to disturbance tolerance and habit types, as well as functional feeding groups. We tested the hypothesis that the postfire responses of invertebrate communities will depend on vegetation burn severity (unburned, low severity, and moderate/ high severity), with responses being greater in moderate/high-severity than unburned or low-severity basins. Our results indicated that the relative abundances of sensitive invertebrates decreased and tolerant taxa increased after fire at sites draining catchments burned at moderate/high severity, and few postfire impacts were found on invertebrates at sites draining catchments that burned at low severity, relative to unburned sites. Regarding the relative abundances of trait groups, shredder abundance was higher at low-severity burned sites compared to sites burned at moderate/high severity and unburned sites throughout the study, and sprawler abundance was higher at low-severity burn sites compared to moderate/high-severity burn sites and unburned basins in 2013. However, values of all invertebrate variables in moderately/highly burned reaches generally returned to unburned levels by 2 years postfire. Stream geomorphological variables, specifically changes in the vertical profile of the stream channel over time, were negatively correlated with taxa richness, family biotic index, and percentage of shredders. Fire management strategies that prevent or reduce the severity of catastrophic wildfire, such as forest thinning or prescribed fire, as well as efforts to reestablish natural channel morphology, can ameliorate the impacts of wildfire on stream communities and help to establish stable, healthy, and diverse ecosystems in steep environments in the Front Range and elsewhere.
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Veech, Joseph A. "Analysis of the Habitat Associations of a Hypothetical Beetle Species." In Habitat Ecology and Analysis. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198829287.003.0008.
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A dataset for a hypothetical ground-dwelling beetle species is used to illustrate five methods of habitat analysis: (1) comparison of group means, (2) multiple linear regression, (3) multiple logistic regression, (4) classification and regression trees, and (5) principal components analysis. The dataset consists of abundance (counts of individuals) recorded in each of 100 small survey plots located throughout forested study sites. The following environmental predictor variables were measured in each plot: percentage canopy cover, depth of leaf litter, volume of woody debris, ratio of oak to non-oak trees, and soil type. Techniques for assessing normality of each variable and multicollinearity among variables are discussed and recommended prior to conducting the habitat analysis. Assumptions, strengths, and weaknesses of each method are discussed.
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Hails, Rosemary S. "The population dynamics of the gall wasp Andricus quercuscalicis." In Plant Galls. Oxford University PressOxford, 1994. http://dx.doi.org/10.1093/oso/9780198577690.003.0023.
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Abstract The gall wasp Andricus quercuscalicis invaded Britain from the continent in the early 1960s. The life cycle involves both alternation of generations and alternation of host plants. This study draws on 8 years of population data and considers the factors that limit and regulate the distribution and abundance of A. quercuscalicis. This gall wasp, now abundant, appears to be resource-limited in the agamic generation due to competition for acorns in the ‘low years’ of the acorn cycle. Factors influencing the survivorship of the sexual generation are considered in detail. Although the sexual generation does not appear to be resource-limited, there is evidence of density-dependent mortality during gall establishment. This arises partly as a consequence of the oviposition pattern of the agamic females, because the distribution of eggs is highly aggregated between and within trees. As a result of density-dependent mortality, the distribution of mature galls is less highly clumped. Although the agamic knopper gall suffers only low rates of parasitism from a few species, several native parasitoids attack the sexual gall. The total percentage of parasitism is remarkably consistent from year to year even though the contribution from any one species fluctuates considerably.
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Grout, Paul. "Popular Capitalism." In Privatization and Economic Performance. Oxford University PressOxford, 1994. http://dx.doi.org/10.1093/oso/9780198773436.003.0021.
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Abstract In 1979 the proportion of the adult population of the UK that directly owned shares in companies was 9 per cent. In the last thirteen years this has risen dramatically and it is estimated that 25 per cent of the adult population now own shares. In many ways this has been a spectacular change and one that, in 1979, would have appeared almost impossible to achieve. This seems to indicate that ‘popular capitalism’ has arrived in abundance and has been an unmitigated success. There is, however, another side to the story. In 1975 the percentage of the UK equity market in direct personal ownership was 37.5 per cent. By 1981 this had fallen to below 30 per cent and by the end of the decade was barely above 20 per cent.
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Kharytonova, Yuliia, and Vasil Dyadichko. "LONG-TERM CHANGES OF COPEPODA (CRUSTACEA) ABUNDANCE AND BIOMASS IN THE DANUBE AND ODESA REGIONS OF THE BLACK SEA AS INDICATOR OF WATER QUALITY." In European vector of development of the modern scientific researches. Publishing House “Baltija Publishing”, 2021. http://dx.doi.org/10.30525/978-9934-26-077-3-21.
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Copepoda are the most important zooplanktonic group constituting the primary food for fish larvae and some fishes. Copepoda have the longest life cycles among the Black Sea mesozooplankton, so their biomass and percentage of total zooplankton biomass is greatly reduced by eutrophication. The percentage of Copepoda from the total biomass of zooplankton is a reliable indicator of the ecological status of the water bodies. For the Black Sea marine waters the indicator of “good” ecological status (GES) is the average annual biomass of Copepoda, which exceeds 45% of the total biomass of zooplankton. Changes of total biomass of zooplankton, biomass of Copepoda, the abundance and biomass of dominant species – Oithona davisae Ferrari F. D. & Orsi, 1984, Acartia (Acartiura) clausi Giesbrecht, 1889 and A. (Acanthacartia) tonsa Dana, 1849 in the Danube and Odesa marine regions from 1970 to 2019 were analysed. Also the ecological quality class in the Nort-Western part of Black sea by Copepoda indicators from 2004 to 2017 were established according to Water Framework Directive US. The total zooplankton biomass had been decreasing in Ukrainian waters and % of Copepoda from total zooplankton biomass was increasing. These tendencies shown a positive change in the forage base of commercial planktophagous fishes and ecological class status of the investigated aquatories. The abundance and biomass of O. davisae, A. clausi and A. tonsa were decreased from 2016 to 2019. The highest values of their metrics were in 2016 and the lowest rates observed in 2019. O. davisae, A. clausi and A. tonsa were the main components of copepods number and biomass. The Acartia species formed higher part of Copepoda biomass than O. davisae. The ecological state was “good” (GES) only in Danube-Dnieper coastal waters and Danube delta in 2004–2017 where Copepoda formed more than 45 % of total zooplankton biomass. In waters of Northwester Black Sea bays, shallow and deepwater shelfs the ecological state was “Bad” (notGES), the part of Copepoda was lower than 45 %.
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A. Turcios-Casco, Manfredo, Richard K. LaVal, Marcio Martínez, and Hefer D. Ávila-Palma. "More Urbanization, Fewer Bats: The Importance of Forest Conservation in Honduras." In Natural History and Ecology of Mexico and Central America. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96493.
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Urbanization is a phenomenon that results in fragmentation and eventual destruction of forests. Suburbanization is a subset of that same phenomenon in which fragmentation has resulted in the retention of small patches of the original forest and surviving old growth trees. Alternatively, the area surrounding the central city had been cleared for agricultural use and the suburban residents have planted many trees in parks and private property. This fragmentation will of course affect many species of bats, including species of the family Phyllostomidae. In this work, we estimate and compare the diversity of phyllostomid bats in three landscapes in Honduras: forests, suburban, and urban areas, from 2015 to 2018. Concurrently, we compared bat activity patterns based on the hour and percentage of moonlight at the time they were captured, and we compared external measurements, forearm and ear length. Urban areas are the least diverse and exhibited the lowest abundance. The forearm and ear length were significantly different only between forests and urban areas. The degree of lunar phobia also differed among those landscapes, but the time of capture did not differ. This is the first attempt to describe the activity patterns of phyllostomids in these studied areas and the effect of urbanization on Honduran bats. As expected, we found that from forests to cities, the diversity and abundance of phyllostomids decreased. However, there are many gaps in our knowledge of how totally or partially urbanized areas are affecting phyllostomid bats in Honduras.
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Kompanets, Eduard, and Viktoria Lavrynenko. "ECOSYSTEM CONNECTIONS AND FISH HEALTH." In Priority areas for development of scientific research: domestic and foreign experience. Publishing House “Baltija Publishing”, 2021. http://dx.doi.org/10.30525/978-9934-26-049-0-40.
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Ecosystems are subject to many human influences. The balance between species is disturbed due to interference with the aquatic environment. Due to environmental pollution, its impact on fish and other aquatic organisms changes. This affects ecosystem connections. Changes in the environment also change the adaptive capacity of fish, leading to impaired health. Also, there is a need to study the protective capabilities of fish from the naturally occurring opportunistic species Aeromonas hydrophila, which causes infections in them. In natural hydrobiocenoses, fish, as well as pathogens of its diseases (aeromonads) are components of food chains formed by evolution. Literature sources prove that aeromonads are normally present in microbial associations of benthic microflora as a normal saprophytic component of hydroecosystems. These bacteria feed on organic residues that are concentrated at the bottom of water bodies and perform a sanitary function, like other similar types of microorganisms. The health of fish depends on their ability to adapt to the environment. Usually in the wild, fish are rarely susceptible to disease. Local populations for a long time of coexistence have formed a certain balance with other species, including parasitic. The balance is reflected by a certain rate of abundance between species. Imbalance due to fishing from the reservoir, or, conversely, with an artificial increase in numbers, leads to changes in the aquatic environment. Changes in the habitat of fish affect themselves. Fish health is changing. In nature, such a disease as aeromonosis is an ecological concept. Violation of the ecological conditions of the species leads to stress, and reduced immunity in fish, leads to fish disease. In aeromonad infections with weak symptoms in carp, a decrease in biological parameters was observed: growth, body weight, fatness and survival (57.1%). The number of blood cells in diseased fish decreased, especially leukocytes and lymphocytes. The percentage of T- and B-lymphocytes in the blood of carp-infected carp increased. The introduction of the bacterium stimulated the immune response – an increase in the percentage of T-lymphocytes. The percentage of B cells did not increase significantly. In diseased fish, the percentage and number of low-activity T-lymphocytes increased, which corresponded to the presence of an immune response to the bacterium. The values of antibacterial activity of blood serum (BASC) in both groups of fish did not change.
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Kraft, Theresa A., and Annette Lerine Steenkamp. "A Holistic Approach for Understanding Project Management." In Systems Approach Applications for Developments in Information Technology. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-4666-1562-5.ch003.
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Companies invest significant sums of money in major Information Technology (IT) projects, yet success remains limited. Despite an abundance of IT Project Management (ITPM) resources available to project teams, such as the Project Management Institute (PMI) Body of Knowledge, IT standards and IT governance, a large percentage of IT projects continue to fail and ultimately get scrapped. Recent studies have shown an average of 66% IT project failure rate, with 52% of the projects being cancelled, and 82% being delivered late. The purpose of this research was to provide a way for uncovering potential causes of IT project failures by utilizing a systemic and holistic approach to identify critical success factors for project management. The holistic approach has enabled the development of an ITPM conceptual model, which provides a method to evaluate the critical success factors of a given project, and their alignment with each other. The adoption of the systemic methodology and its implementation increase the potential for IT project success, and alert project leaders of potential problems throughout the life of the project.
Conference papers on the topic "Percentage abundance"
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Grigorova-Pesheva, Bilyana, Biser Hristov, and Kameliya Petrova. "ANALYSIS OF THE MICROBIOLOGICAL CHARACTERISTICS OF THE DIFFERENT SOIL HORIZONS OF FOREST SOILS FROM THE TERRITORY OF VITOSHA NATURE PARK." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/3.1/s14.41.
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The status, abundance and diversity of soil microbial communities are one of the main basic indicators for the assessment and monitoring of forest ecosystems. In the context of the important role that microorganisms play in forest ecosystems, it is crucial to study and monitor their abundance in soil habitats. In order to supplement the knowledge about the soil microbial communities in the different soil horizons, we studied 16 soil profiles from the territory of Vitosha Nature Park. The soils from tested areas 1-8 are determined as Dystric Cambisols and the soils form tested areas 9-16 as Umbrisols. The main soil characteristics: pH, total nitrogen content, humus and organic carbon content have been studied using standard laboratory analyses. The total microbial number of the individual soil horizons have been established respectively for the Dystric Cambisols A and B horizons, for the Umbrisols A1 and A horizons. The Koch method was used. The percentage distribution of the main microbial groups: spore-forming and non-sporeforming microorganisms, actinomycetes and micromycetes have been determined. For all studied soils, a decrease in the total microflora with an increase in the depth of the soil profile was found. In Umbrisols this decrease is less compared to Dystric Cambisols. In both soil types, the results show a significant reduction in the group of micromycetes in the underlying soil horizon, regardless of soil type. In soils with higher acidity, a higher percentage of the micromycetes is observed, regardless of soil type and soil horizon. Higher values of the correlation coefficient were found when comparing the microbial abundance in the lower soil horizons with the humus content, compared to the upper soil horizons.
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Xia, Han, and M. Bakker. "Quality of open air, single-shot LIBS spectra from waste particles." In OCM 2015 - 2nd International Conference on Optical Characterization of Materials. KIT Scientific Publishing, 2015. http://dx.doi.org/10.58895/ksp/1000044906-14.
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This work investigates the ability of LIBS to produce quality spectra from small particles of concrete demolition waste with single-shot spectra in open air. The 2 − 8mm materials are rounded river gravel, green glass shards and plastic flakes. Considered are focal length, air, moisture, laser energy and laser angle of incidence. The research methodology is an experimental study using the observation depth and spectral abundance as quality indicators. The relation between ablation volume, breakdown threshold, signal strength and observation depth is captured in a simplified model to provide a better understanding of the dependence of the spectra on the laser incidence angle and material positioning in the laser beam. A 100mm lens provided a compromise between spectral abundance, level of air interference and achievable observation depth. The study indicates LIBS can yield good quality data, even in cases of up to 3mm surface roughness. Surface moisture did raise the percentage of bad spectra from an average 4% to 18%, but overall LIBS is still capable of providing quality data under challenging conditions.
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Anding, Katharina, Petr Kuritcyn, Elske Linss, and S. Latyev. "Significant characteristics in VIS- and IR-spectrum of construction and demolition waste for high-precision supervised classification." In OCM 2015 - 2nd International Conference on Optical Characterization of Materials. KIT Scientific Publishing, 2015. http://dx.doi.org/10.58895/ksp/1000044906-13.
Full textAbstract:
This work investigates the ability of LIBS to produce quality spectra from small particles of concrete demolition waste with single-shot spectra in open air. The 2 − 8mm materials are rounded river gravel, green glass shards and plastic flakes. Considered are focal length, air, moisture, laser energy and laser angle of incidence. The research methodology is an experimental study using the observation depth and spectral abundance as quality indicators. The relation between ablation volume, breakdown threshold, signal strength and observation depth is captured in a simplified model to provide a better understanding of the dependence of the spectra on the laser incidence angle and material positioning in the laser beam. A 100mm lens provided a compromise between spectral abundance, level of air interference and achievable observation depth. The study indicates LIBS can yield good quality data, even in cases of up to 3mm surface roughness. Surface moisture did raise the percentage of bad spectra from an average 4% to 18%, but overall LIBS is still capable of providing quality data under challenging conditions.
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Bajić, Aleksandar, Nikola Z. Grujić, and Mladen Horvatović. "ECOLOGICAL INTERACTION BETWEEN FAXONIUS LIMOSUS (RAFINESQUE, 1817) AND PONTASTACUS LEPTODACTYLUS (ESCHSCHOLTZ, 1823) IN THE DANUBE RIVER." In 54. godišnja konferencija o aktuelnim problemima korišćenja i zaštite voda. Srpsko društvo za zaštitu voda, 2025. https://doi.org/10.46793/voda25.123b.
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During 2024, sampling of crayfish was carried out at four sites along the Danube river through Serbia: Apatin, Bogojevo, Begeč and Sremski Karlovci. The presence of two species of crayfish, the invasive spinycheek crayfish (Faxonius limosus) and the native Danube crayfish (Pontastacus leptodactylus), was detected at all four sites. The abundance of Faxonius limosus ranged from 53% to over 99%. The percentage of males was about 60%. The mean Fulton Conditioning Factor ranged from 0.0304 to 0.0372 and was higher in males than in females. Danube crayfish had lower values of the Fulton conditioning factor, while the values of the Crayfish constant were higher than in spinycheek crayfish.
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Burke, Mary, and Shobhana Chelliah. "Challenges to Representing Personal Names and Language Names in Language Archives: Examples from Northeast India." In International Workshop on Digital Language Archives. University of North Texas, 2021. http://dx.doi.org/10.12794/langarc1851173.
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Language archives are not only a valuable resource for language communities to tell their stories and to create lasting records of their ways of life, but also for those interested in anthropology, linguistics, agriculture, or art history. This recent emphasis on archiving primary datasets in linguistics has resulted in an abundance of datasets online; however, of the languages of South Asia, only a small percentage are represented in digital language archives or described thoroughly. Though several of these languages are being documented, this material is at risk of being lost or inaccessible without concerted attention paid to long-term preservation. There are several obstacles to documenting and archiving language materials from this area, including political instability and lack of access to infrastructure. This submission reviews one particular challenge to data management relevant to South Asia, which is the complexity of names (of individuals, groups, and languages). We provide examples from Northeast India and recommendations based on experience from CoRSAL (Computational Resource for South Asia).
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Burke, Mary, and Shobhana Chelliah. "Challenges to Representing Personal Names and Language Names in Language Archives: Examples from Northeast India." In International Workshop on Digital Language Archives. University of North Texas, 2021. http://dx.doi.org/10.12794/langarc1851173.
Full textAbstract:
Language archives are not only a valuable resource for language communities to tell their stories and to create lasting records of their ways of life, but also for those interested in anthropology, linguistics, agriculture, or art history. This recent emphasis on archiving primary datasets in linguistics has resulted in an abundance of datasets online; however, of the languages of South Asia, only a small percentage are represented in digital language archives or described thoroughly. Though several of these languages are being documented, this material is at risk of being lost or inaccessible without concerted attention paid to long-term preservation. There are several obstacles to documenting and archiving language materials from this area, including political instability and lack of access to infrastructure. This submission reviews one particular challenge to data management relevant to South Asia, which is the complexity of names (of individuals, groups, and languages). We provide examples from Northeast India and recommendations based on experience from CoRSAL (Computational Resource for South Asia).
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Perry, Sheridan, Victor Huayamave, Bryan Gonzalez, Zachary Nadeau, and Rafael Rodriguez. "3D Printing Material Testing and Applications in Biomaterial Modeling for Pediatric Medical Trainers." In ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-94352.
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Abstract Additive manufacturing technologies have become increasingly prevalent in recent years and, with their abundance, have opened many doors in the field of manufacturing and design. The field of medicine has always been in high demand for new manufacturing techniques to create medical prostheses, devices, and trainers. With this increased need, 3D printing has become the obvious solution, and with it, a major problem has arisen. The lack of material property data on 3D printing filament post extrusion leaves designers and engineers having to perform extraneous tests to create accurate models. This paper summarizes an analyses of a common 3D printing filament known as Thermoplastic Polyurethane (TPU). The analysis included tensile testing in accordance with ASTM D638-14 and preliminary FEA based on the material properties found. It was found that TPU is a material that behaves in a similar manner to an elastomer with a low ultimate stress (50% infill yields 23.92 MPa +1.38 −1.12) and relatively low moduli of elasticity (50% infill sample 23.13 MPa +0.91 −0.87). TPU’s material characteristics change in respect to its infill percentage. A preliminary FEA analysis was also performed with results that agree with the material testing. Overall, the results from the physical testing and the FEA analysis were in agreement and allows for the creation of a foundation to extend the FEA validation with complex geometric models modeled after organic biomedical components.
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Крылова, Т. Б. "SVYOKLINO I – A STONE AGE WORKSHOP IN THE UPPER REACHES OF THE VOLGA RIVER." In Материалы 23–25-го заседаний научно-методического семинара «Тверская земля и сопредельные территории в древности». Crossref, 2024. https://doi.org/10.70203/7325.2024.69.50.003.
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Мастерская Свёклино I находится в верхнем течении р. Волги, у д. Свёклино Ржевского района Тверской области, вблизи коренных выходов кремня и поселения-мастерской Свёклино. Памятник был выявлен в 1977 г. и исследовался в 1977 и 1979 годах, работы носили рекогносцировочный характер. Артефакты раннего железного века и Средневековья немногочисленны, основная часть материалов относится к каменному веку. В коллекции резко преобладает кремнёвый инвентарь, неолитическая керамика представлена единичными фрагментами и не одновременна. Кремнёвый инвентарь неоднороден. Его характерные особенности: многочисленность первичных и полупервичных сколов и изделий из таких сколов; обилие крупных пластин, изготовленных в технике удара, большой процент нуклеусов и фрагментов нуклеусов, малое количество орудий чётких форм, грубость и лаконичность вторичной обработки, полное отсутствие наконечников стрел. The workshop of Svyoklino I is located in the upper reaches of the Volga River, near the village of Svyoklino, Rzhevsky District, Tver Region, near the indigenous outcrops of fl int and the settlement-workshop of Svyoklino. The site was found in 1977 and studied in 1977 and 1979, the work was carried out as a recocnaissance. Finds of the Early Iron Age and the Middle Ages are few, the bulk of the materials belong to the Stone Age. The collection is sharply dominated by fl int inventory, Neolithic ceramics are singular and non-uniform. Flint inventory is heterogeneous. Its characteristic features: the multiplicity of primary and semi-primary chips and products from such chips; an abundance of large plates made in the technique of impact, a large percentage of nuclei and fragments of nuclei, a small number of tools of clear shapes, roughness and conciseness of secondary processing, the complete absence of arrowheads.
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Aguila, Rupert Karlo D., Edwin N. Quiros, and Jose Gabriel E. Mercado. "Investigation of Performance and Emissions of a CRDI Passenger Van Fuelled With Coconut Methyl Ester-Diesel Blends Using Drive Cycle and Steady Speed Operation." In ASME 2020 14th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/es2020-1708.
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Abstract For the past years, Different Philippine local regulations have been imposed to address oil importation and to address environment concerns. One requirement is reduced emission from diesel engines and at the same time reduce the use of fossil fuels for the. In accordance to the Clean Air Act and the Biofuels Act, The Philippine government is looking for possible alternatives to fossil fuels, One of the biodiesel the country is currently using is coconut methyl ester due to the abundance of coconut trees in the country. This research shows the performance and emission characteristics of diesel blended with coconut methyl ester in a CRDi Passenger van and will help the government justify the increase in blend percentage mandated in commercial fuels. This study is investigates 0%, 2%, 5% 10% and 20% Coconut Methyl Ester (CME)-diesel blends. The experiment consisted of Japanese 10-15 standard drive cycle test, steady state test at 40,60, & 80 kph was performed in the Vehicle Research and Testing Laboratory in the University of the Philippines Diliman equipped with chassis dynamometer, fuel flow meter and emissions analyzer. Performance parameters measured are Power, Specific Fuel Consumption and Mileage, while emission characteristics for CO, NOx, THC are measured. PM measurements were not measured for this experiment. In both Drive cycle and steady state test specific fuel consumption and mileage improved with addition of CME, however results showed they are independent of CME percentage. The best improvement was observed with 5%CME blended with neat diesel at 4.8% and 8.5% for drive cycle and steady state test respectively. Majority of the CME-diesel blends showed decrease in emission specifically in CO and THC emission which is consistent to published literature. For both steady state test and drive cycle test up to 29.5% decrease inn CO and up to 64% decrease in THC was observed. This can be attributed to the overall lean mixtures and in the increase of oxygenated fuel at higher CME blends. NOx emission however is consistent for all fuel blends in the drive cycle test while for the steady state test NOx emission is dependnt on the engine speed. Decreasing trend was obtained for 40 and 60 km/h while increasing trend was obtrained at 80 km/h, with respect to %CME. Average power produced for all the speeds was basically constant for all the blends as compared with neat diesel. Lastly, maximum power showed insignificant changes although majority of the blends showed a minimal power reduction as compared to neat diesel.
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Roy-Aikins, Joseph, and Reshleu J. Rampershad. "Technical and Economic Analysis of Repowering a Coal-Fired Power Plant." In ASME 1999 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/99-gt-007.
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Owing to an abundance of coal reserves, about 92 percent of the electrical power produced in South Africa is generated in central power stations fired on cheaply priced coal. With a few power stations approaching the end of their design life, the question arises as to what to do with these outdated and inefficient plants. Retrofitting or repowering a station with gas turbines is one option being considered. As a case study, this paper investigates the technical and economic feasibility of repowering the Arnot power station to convert it to a combined cycle plant with increased capacity. This power station has six generating units, each of nominal capacity 350 MW and of average age 25 years. Four are in service, and the others are in reserve storage. Several repowering options were considered and the proposed re-design is parallel repowering, where additional steam for a steam turbine is generated in a gas turbine heat recovery steam generator to supplement the steam generated in a coal-fired boiler. Since natural gas, the preferred fuel for gas turbines, is not readily available in the country, kerosene was used as gas turbine fuel. Consequently, the performance of the chosen gas turbine had to be re-evaluated. The output of each unit increased by 77 MW and the efficiency by 8 percentage points to 43 percent, after repowering. Repowering was feasible, technically. An economic analysis was required to determine the magnitude of the economic benefits of repowering, if any, and it turned out that the cost of electricity generated by the new technology was higher than that produced by the outgoing one. It was concluded, therefore, that repowering the steam turbine units with gas turbines fired on kerosene was uneconomical, for the performance level achieved.
Reports on the topic "Percentage abundance"
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Jones, Graham, Diane Fraser, Urvashi Lallu, and Sarah-Jayne Fenwick. Perceptions and Impacts: An Observational Pilot Study of the Effects of Argentine Ants on Honey Bees in New Zealand. Unitec ePress, 2016. http://dx.doi.org/10.34074/pibs.rs12016.
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The Argentine ant (Linepithema humile) is an invasive species first identified in New Zealand in 1990. It is an aggressive tramp species that can form very large ‘super colonies’ extending over vast areas and has been reported to rob honey and predate honey bees in hives. This pilot study sought to establish, from a circulated survey of beekeepers, which ant species were present in their hives and what awareness the beekeepers had of the potential impact of Argentine ants. In addition, a simple method of quantifying the effects of the Argentine ant on brood abundance was trialled in the field. Results indicate that several species of ant are commonly found in hives and that surveyed beekeepers generally regard ants as passive occupiers. A percentage cover estimate of brood cover in frames may be a simple way of measuring ant impact when comparing hives uninfected by ants.Photographic evidence is presented as further indication that L. humile foraged within the hive and actively fed on both honey and emerging brood.
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O'Neill, H. B., S. A. Wolfe, and C. Duchesne. Ground ice map of Canada. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/330294.
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This Open File presents national-scale mapping of ground ice conditions in Canada. The mapping depicts a first-order estimate of the combined volumetric percentage of excess ice in the top 5 m of permafrost from segregated, wedge, and relict ice. The estimates for the three ice types are based on modelling by O'Neill et al. (2019) (https://doi.org/10.5194/tc-13-753-2019), and informed by available published values of ground ice content and expert knowledge. The mapping offers an improved depiction of ground ice in Canada at a broad scale, incorporating current knowledge on the associations between geological and environmental conditions and ground ice type and abundance. It provides a foundation for hypothesis testing related to broad-scale controls on ground ice formation, preservation, and melt. Additional compilation of quantitative field data on ground ice and improvements to national-scale surficial geology mapping will allow further assessment and refinement of the representation of ground ice in Canada. Continued research will focus on improving the lateral and vertical representation of ground ice required for incorporation into Earth system models and decision-making. Spatial data files of the mapping are available as downloads with this Open File.
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van Gemert, Rob, Per Holliland, Konrad Karlsson, Niklas Sjöberg, and Torbjörn Säterberg. Assessment of the eel stock in Sweden, spring 2024 : fifth post-evaluation of the Swedish eel management. Department of Aquatic Resources, Swedish University of Agricultural Sciences, 2024. http://dx.doi.org/10.54612/a.4iseib7eup.
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For decades, the population of the European eel has been in severe decline. In 2007, the European Union decided on a Regulation establishing measures for the recovery of the stock, which obliged Member States to implement a national Eel Management Plan by 2009. Sweden submitted its plan in 2008. According to the Regulation, Member States shall report regularly to the EU-Commission, on the implementation of their Eel Management Plans and the progress achieved in protection and restoration. The current report provides an assessment of the eel stock in Sweden as of spring 2024, intending to feed into the national reporting to the EU in August this year. This report updates and extends previous evaluation reports by Dekker (2012, 2015) and Dekker et al. (2018, 2021). In this report, the impacts on the stock - of fishing, restocking and mortality related to hydropower generation - are assessed. Other anthropogenic impacts (climate change, pollution, increased impacts of predators, spread of parasites, disruption of migration due to disorientation after transport, and so forth) probably have an impact on the stock too, but these factors are hardly quantifiable, and no management targets have been set. For that reason, and because most factors were not included in the EU Eel Regulation, these other factors are not included in this report. Our focus is on the quantification of silver eel biomass escaping from continental waters towards the ocean (current, current potential and pristine) and mortality risks endured by those eels during their whole lifetime. The assessment is broken down on a geographical basis, with different impacts dominating in different areas (west coast, inland waters, Baltic coast). In the last decade, a break in the downward trend in glass eel recruitment has been observed, with recruitment no longer declining consistently. Whether that relates to recent protective actions, or is due to other factors, is yet unclear. Nevertheless, recruitment levels remain at historically low levels. This report contributes to the required international assessment, but does not discuss the causing factors behind the recent recruitment trend and the overall status of the stock across Europe. For the different assessment areas, results summarise as follows: On the west coast, a commercial fyke net fishery on yellow eel was exploiting the stock, until this fishery was completely closed in spring 2012. A fishery-based assessment no longer being achievable, we present trends from research surveys (fyke nets). Insufficient information is currently available to assess the recovery of the stock in absolute terms. Obviously, current fishing mortality is zero (disregarding the currently unquantifiable effect of illegal fishing), but none of the other requested stock indicators (current, current potential and pristine biomass) can be presented. The formerly exploited size-classes of the stock show a recovery in abundance after the closure of the commercial fishery, and the smaller size classes show a break in their decline in line with the recent global trend of glass eel recruitment. In order to support the recovery of the stock, or to compensate for anthropogenic mortality in inland waters, young eel has been restocked on the Swedish west coast since 2010. Noting the quantity of restocking involved, the expected effect (ca. 50 t silver eel) is relatively small, and hard to verify – in comparison to the potential natural stock on the west coast (an order of 1000 t). However, for the currently depleted stock, the contribution will likely constitute a larger share of silver eel escapement. For inland waters, this report updates the 2021 assessment, with substantial changes in methodology being the use of a new natural recruitment model, and the full separation of Trap & Transport catches from the fisheries statistics. The assessment for the inland waters relies on a reconstruction of the stock from information on the youngest eels in our waters (natural recruits, assisted migration, restocking). Based on 78 years of data on natural recruitment into 22 rivers, a statistical model is applied which relates the number of immigrating young eel caught in traps to the location and size of each river, the distance from the trap to the river mouth, and the year in which those eels recruited to continental waters as a glass eel (year class). The further into the Baltic, the larger and less numerous recruits generally are. Distance upstream comes with less numerous recruits. Using the results from the above recruitment analysis, in combination with historical data on assisted migration (young eels transported upstream within a drainage area, across barriers) and restocking (young eels imported into a river system), we have a complete overview of how many young eels recruited to Swedish inland waters. From this, the production of fully grown silver eel is estimated for every lake and year separately, based on best estimates of growth and natural mortality rates. Subtracting the catch made by the fishery (as recorded) and down-sizing for the mortality incurred when passing hydropower stations (percentwise, as recorded or using a default percentage), an estimate of the biomass of silver eel escaping from each river towards the sea is derived. Results indicate, that since 1960, the production of silver eel in inland waters has declined from over 700 to below 300 tonnes per year (t/yr). The production of naturally recruited eels is still falling; following the increase in restocking since 2010, an increase in restocking-based production is expected to be starting right around now. Gradually, restocking has replaced natural recruitment (assisted and fully natural), now making up over 90 % of the inland stock. Fisheries have taken 20-30 % of the silver eel (since the mid-1980s), while the impact of hydropower has ranged from 25 % to 60 %, depending on the year. Escapement is estimated to have varied from 72 t in the late 1990s, to 175 t in the early 2000s. The biomass of current escapement (including eels of restocked origin) is approximately 15 % of the pristine level (incl. restocked), or almost 30 % of the current potential biomass (incl. restocked). This is below the 40 % biomass limit of the Eel Regulation, and anthropogenic mortality (70 % over the entire life span in continental waters) exceeds the limit implied in the Eel Regulation (60 % mortality, the complement of 40 % survival). Mortality being that high, Swedish inland waters currently do not contribute to the recovery of the stock. The temporal variation (in production, impacts and escapement) is partly the consequence of a differential spatial distribution of the restocking of eel over the years. The original natural (not assisted) recruits were far less impacted by hydropower, since they could not climb the hydropower dams when immigrating. Since 2010, inland restocking is increasingly concentrated to drainage areas falling to the Kattegat-Skagerrak, also including obstructed lakes (primarily Lake Vänern, and many smaller ones). Even though Trap & Transport of silver eel - from above barriers towards the sea - has contributed to reducing the hydropower impact, hydropower mortality remains the largest estimated contributor to silver eel mortality in inland waters. Without restocking, the biomass affected by fishery and/or hydropower would be only 5-10 % of the currently impacted biomass, but the stock abundance would reduce from 15 % to less than 3 % of the pristine biomass. In summary: the inland eel stock biomass is below the minimum target, anthropogenic impacts exceed the minimum limit that would allow recovery, and those impacts have been increasing. It is therefore recommended to reconsider the current action plans on inland waters, taking into account the results of the current, comprehensive assessment. For the Baltic coast, the 2021 assessment has been updated without major changes in methodology. Results indicate that the impact of the fishery continues to decline over the decades. The current impact of the Swedish silver eel fishery on the escapement of silver eel along the Baltic Sea coast is estimated at 0.3 %. However, this fishery is just one of the anthropogenic impacts (in other areas/countries) affecting the eel stock in the Baltic, including all types of impacts, on all life stages and all habitats anywhere in the Baltic. Integration with the assessments in other countries has not been achieved. Current estimates of the abundance of silver eel (biomass) indicates an order of several thousand tonnes, but those estimates are extremely uncertain, due to the low impact of the fishery (near-zero statistics). Moreover, these do not take into account the origin of those silver eels, from other countries. An integrated assessment for the whole Baltic will be required to ground-truth these estimates. This would also bring the eel assessments in line with the policy to regionalise stock assessments for other (commercial) fish species (see https://ec.europa.eu/oceans-and-fisheries/fisheries/rules/multiannual-plans_en). It is recommended to develop an integrated assessment for the entire Baltic Sea eel stock, and to coordinate protective measures with other range states.
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Ley, Matt, Tom Baldvins, David Jones, Hanna Pilkington, and Kelly Anderson. Vegetation classification and mapping: Gulf Islands National Seashore. National Park Service, 2023. http://dx.doi.org/10.36967/2299028.
Full textAbstract:
The Gulf Islands National Seashore (GUIS) vegetation inventory project classified and mapped vegetation on park-owned lands within the administrative boundary and estimated thematic map accuracy quantitatively. The project began in June 2016. National Park Service (NPS) Vegetation Mapping Inventory Program provided technical guidance. The overall process included initial planning and scoping, imagery procurement, field data collection, data analysis, imagery interpretation/classification, accuracy assessment (AA), and report writing and database development. Initial planning and scoping meetings took place during May, 2016 in Ocean Springs, Mississippi where representatives gathered from GUIS, the NPS Gulf Coast Inventory and Monitoring Network, and Colorado State University. Primary imagery used for interpretation was 4-band (RGB and CIR) orthoimages from 2014 and 2016 with resolutions of 15 centimeters (cm) (Florida only) and 30 cm. Supplemental imagery with varying coverage across the study area included National Aerial Imagery Program 50 cm imagery for Mississippi (2016) and Florida (2017), 15 and 30 cm true color Digital Earth Model imagery for Mississippi (2016 and 2017), and current and historical true-color Google Earth and Bing Map imagery. National Oceanic Atmospheric Administration National Geodetic Survey 30 cm true color imagery from 2017 (post Hurricane Nate) supported remapping the Mississippi barrier islands after Hurricane Nate. The preliminary vegetation classification included 59 United States National Vegetation Classification (USNVC) associations. Existing vegetation and mapping data combined with vegetation plot data contributed to the final vegetation classification. Quantitative classification using hierarchical clustering and professional expertise was supported by vegetation data collected from 250 plots in 2016 and 29 plots in 2017 and 2018, as well as other observational data. The final vegetation classification includes 39 USNVC associations and 5 park special types; 18 forest and woodland, 7 shrubland, 17 herbaceous, and 2 sparse vegetation types were identified. The final GUIS map consists of 38 map classes. Land cover classes include four types: non-vegetated barren land / borrow pit, developed open space, developed low – high intensity, and water/ocean. Of the 34 vegetation map classes, 26 represent a single USNVC association/park special, six map classes contain two USNVC associations/park specials, and two map classes contain three USNVC associations/park specials. Forest and woodland associations had an abundance of sand pine (Pinus clausa), slash pine (Pinus elliottii), sand live oak (Quercus geminata), yaupon (Ilex vomitoria), wax myrtle (Morella cerifera), and saw palmetto (Serenoa repens). Shrubland associations supported dominant species such as eastern baccharis (Baccharis halimifolia), yaupon (Ilex vomitoria), wax myrtle (Morella cerifera), saw palmetto (Serenoa repens), and sand live oak (Quercus geminata). Herbaceous associations commonly included camphorweed (Heterotheca subaxillaris), needlegrass rush (Juncus roemerianus), bitter seabeach grass (Panicum amarum var. amarum), gulf bluestem (Schizachyrium maritimum), saltmeadow cordgrass (Spartina patens), and sea oats (Uniola paniculata). The final GUIS vegetation map consists of 1,268 polygons totaling 35,769.0 hectares (ha) or 88,387.2 acres (ac). Mean polygon size excluding water is 3.6 ha (8.9 ac). The most abundant land cover class is open water/ocean which accounts for approximately 31,437.7 ha (77,684.2 ac) or 87.9% of the total mapped area. Natural and ruderal vegetation consists of 4,176.8 ha (10,321.1 ac) or 11.6% of the total area. Within the natural and ruderal vegetation types, herbaceous types are the most extensive with 1945.1 ha (4,806.4 ac) or 46.5%, followed by forest and woodland types with 804.9 ha (1,989.0 ac) or 19.3%, sparse vegetation types with 726.9 ha (1,796.1 ac) or 17.4%, and shrubland types with 699.9 ha (1,729.5 ac) or 16.8%. Developed open space, which can include a matrix of roads, parking lots, park-like areas and campgrounds account for 153.8 ha (380.0 ac) or 0.43% of the total mapped area. Artificially non-vegetated barren land is rare and only accounts for 0.74 ha (1.82 ac) or 0.002% of the total area. We collected 701 AA samples to evaluate the thematic accuracy of the vegetation map. Final thematic accuracy, as a simple proportion of correct versus incorrect field calls, is 93.0%. Overall weighted map class accuracy is 93.6%, where the area of each map class was weighted in proportion to the percentage of total park area. This method provides more weight to larger map classes in the park. Each map class had an individual thematic accuracy goal of at least 80%. The hurricane impact area map class was the only class that fell below this target with an accuracy of 73.5%. The vegetation communities impacted by the hurricane are highly dynamic and regenerated quickly following the disturbance event, contributing to map class disagreement during the accuracy assessment phase. No other map classes fell below the 80% accuracy threshold. In addition to the vegetation polygon database and map, several products to support park resource management are provided including the vegetation classification, field key to the associations, local association descriptions, photographic database, project geodatabase, ArcGIS .mxd files for map posters, and aerial imagery acquired for the project. The project geodatabase links the spatial vegetation data layer to vegetation classification, plot photos, project boundary extent, AA points, and the PLOTS database. The geodatabase includes USNVC hierarchy tables allowing for spatial queries of data associated with a vegetation polygon or sample point. All geospatial products are projected using North American Datum 1983 (NAD83) in Universal Transverse Mercator (UTM) Zone 16 N. The final report includes methods and results, contingency tables showing AA results, field forms, species list, and a guide to imagery interpretation. These products provide useful information to assist with management of park resources and inform future management decisions. Use of standard national vegetation classification and mapping protocols facilitates effective resource stewardship by ensuring the compatibility and widespread use throughout the NPS as well as other federal and state agencies. Products support a wide variety of resource assessments, park management and planning needs. Associated information provides a structure for framing and answering critical scientific questions about vegetation communities and their relationship to environmental processes across the landscape.