Journal articles on the topic 'Abundance'
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List Sánchez, Rurik H., and David W. Macdonald. "Carnivora atnd their larger mammalian prey species invenory and abundance in the Janos-Nuevo Casas Grandes praire dog complex, Chihuahua." Revista Mexicana de Mastozoología (Nueva Epoca) 3, no. 1 (January 23, 2014): 95. http://dx.doi.org/10.22201/ie.20074484e.1998.3.1.62.
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Abstract. This study examined the carnivore species composition and abundance in the Janos-Nuevo Casas Grandes prairie dog complex of north-western Chihuahua, Mexico. Thirteen species of carnivores were recorded in habitats including prairie dog towns, grassland, mesquite scrub and riparian vegetation. From artificial scent-stations and spotlight transects the most abundant carnivore species appeared to be the kit fox Vulpes macrotis and the coyote Canis latrans. Striped/hooded skunks (Mephitis spp) and American badgers (Taxidea taxus) were also common. No significant differences were found between the abundance of kit foxes or coyotes on prairie dog towns or grassland; but skunks were more abundant on grasslands. The abundance of hares (Lepus californicus), rabbit (Sylvilagus audubonii), and kangaroo rat (Dipodomys spp) was also estimated; hares and kangaroo rats were more abundant in the grassland, whilst rabbits were more abundant in prairie dog towns.Resumen. Se estudió la composición de espeices de carnívoros en el complejo de perros llaneros Janos-Nuevo Casas Grandes, en el noroeste de Chihuahua, México. Se registraron 13 especies de carnívoros en los siguientes hábitats; colonias de perros lIaneros, pastizal, matorral de mezquite y vegetación riparia. Por medio de estaciones olfativas y transectos de lampareo se determinó que la zorra norteña Vulpes macrotis y el coyote Canis latrans fueron los más abundantes. Los zorrillos (Mephitis spp) y tejones (Taxidea taxus) también fueron comunes. No se encontraron diferencias significativas en la abundancia de zorras norteñas o coyotes entre colonias de perros llaneros o pastizal. Los zorrillos fueron más abundantes en el pastizal. También se estimó la abundancia de liebres (Lepus californicus), conejos (Sylvilagus audubonii), y ratas canguro (Dipodomys spp); las liebres y ratas canguro son más abundantes en el pastizal, mientras los conejos son mas abundantes en las colonias de perros lIaneros.Key words: Carnivore abundance, Chihuahua, Mexico, prairie dog, scent-station, spotlighting.
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Sherman, CS, MR Heupel, SK Moore, A. Chin, and CA Simpfendorfer. "When sharks are away, rays will play: effects of top predator removal in coral reef ecosystems." Marine Ecology Progress Series 641 (May 7, 2020): 145–57. http://dx.doi.org/10.3354/meps13307.
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Shark abundances are decreasing on many coral reefs, but the ecosystem effects of this loss are poorly understood. Rays are a prevalent mesopredator in tropical coral reef ecosystems that are preyed upon by top predators like sharks. Studies have suggested reduced predator abundances lead to increases in mesopredator abundance (mesopredator release). We examined the relationship between top predator abundances and the abundance and behaviour of 2 small benthic ray genera using baited remote underwater video systems (BRUVS) across 6 countries. Where predators were more abundant, 2 genera of small benthic rays were sighted less often, possibly because of lower abundances. Small ray behaviour was also significantly affected by predator abundance. Individuals of focal ray species visited BRUVS significantly fewer times at sites with higher predator abundances. Where predators were less abundant, rays spent significantly more time in the video frame, and were more likely to feed from bait bags. In addition to predator abundance, small ray presence was significantly influenced by reef relief and depth. Neotrygon spp. were more abundant on deeper, lower relief habitats, while Taeniura spp. were more prevalent in reef-associated shallow, high relief habitats. Overall, this study found that predator abundance had a significant effect on small benthic ray abundance and behaviour in the presence of BRUVS. Results demonstrate that changes in both abundance and behaviour associated with predator loss may make the interpretation of phenomenon like mesopredator release more difficult to identify unless behavioural effects are considered.
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Crozier, Gaea E., and Dale E. Gawlik. "Avian Response to Nutrient Enrichment in an Oligotrophic Wetland, the Florida Everglades." Condor 104, no. 3 (August 1, 2002): 631–42. http://dx.doi.org/10.1093/condor/104.3.631.
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Abstract We studied the effects of nutrient enrichment on the bird community in an oligotrophic wetland, the Florida Everglades. Among the non-wading birds surveyed in 1996 and 1997, Boat-tailed Grackles (Quiscalus major) and Common Moorhens (Gallinula chloropus) were consistently more abundant in enriched sites, whereas Common Yellowthroats (Geothlypis trichas) were consistently more abundant in unenriched sites. The abundance of Red-winged Blackbird (Agelaius phoeniceus) was not significantly different between enriched and unenriched sites. Among wading birds, Wood Storks (Mycteria americana) and Great Egrets (Ardea alba) were significantly more abundant in enriched than unenriched areas in a dry year, 1991. Great Egrets and all wading species combined were significantly more abundant in enriched than unenriched areas in the wet year, 1995. Great Blue Herons (Ardea herodias) and White Ibises (Eudocimus albus) did not differ in abundance between enriched and unenriched areas in the dry or wet year. A significant interaction between water depth and nutrient status in the wet year indicated that wading bird abundance increased with water depth only in nutrient-enriched areas presumably because the enriched areas had greater food availability than unenriched areas at the same water depth. Bird abundance appeared to increase in nutrient-enriched areas; however, this increase was accompanied by a shift in species composition typically found in the unenriched Everglades and was a fundamental change in the Everglades' distinctive structure. Respuestas de las Aves al Enriquecimiento con Nutrientes en un Humedal Oligotrófico, en los Pantanos de los Everglades en Florida Resumen. Estudiamos los efectos del enriquecimiento con nutrientes sobre la comunidad de aves en un humedal oligotrófico, los pantanos de los Everglades en Florida. Entre las aves no vadeadoras censadas en 1996 y 1997, Quiscalus major y Gallinula chloropus fueron consistentemente más abundantes en sitios enriquecidos, mientras que Geothlypis trichas fue consistentemente más abundante en sitios no enriquecidos. La abundancia de Agelaius phoeniceus no difirió significativamente entre los sitios enriquecidos y no enriquecidos. Entre las aves vadeadoras, Mycteria americana y Ardea alba fueron significativamente más abundantes en áreas enriquecidas que en las no enriquecidas durante 1991, un año seco. En 1995, un año húmedo, Ardea alba y todas las demás aves vadeadoras fueron significativamente más abundantes en áreas enriquecidas que en las no enriquecidas. Ardea herodias y Eudocimus albus no difirieron en abundancia entre áreas enriquecidas y no enriquecidas en el año húmedo ni en el año seco. En el año húmedo, encontramos una interacción significativa entre la profundidad del agua y el estado de los nutrientes, lo que indicó que la abundancia de aves vadeadoras aumentó sólo en las áreas enriquecidas con nutrientes, presumiblemente debido a que las áreas enriquecidas presentaron mayor disponibilidad de alimento que las áreas no enriquecidas de una profundidad de agua equivalente. La abundancia de aves pareció aumentar en las áreas enriquecidas con nutrientes; sin embargo, este incremento estuvo acompañado con un cambio en la composición de las especies encontradas normalmente en los pantanos de los Everglades de Florida que no han sido enriquecidos, y representó un cambio fundamental en la estructura característica de los Everglades.
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Irvine, James R., and Masa-aki Fukuwaka. "Pacific salmon abundance trends and climate change." ICES Journal of Marine Science 68, no. 6 (March 2, 2011): 1122–30. http://dx.doi.org/10.1093/icesjms/fsq199.
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Abstract Irvine, J. R., and Fukuwaka, M. 2011. Pacific salmon abundance trends and climate change. – ICES Journal of Marine Science, 68: 1122–1130. Understanding reasons for historical patterns in salmon abundance could help anticipate future climate-related changes. Recent salmon abundance in the northern North Pacific Ocean, as indexed by commercial catches, has been among the highest on record, with no indication of decline; the 2009 catch was the highest to date. Although the North Pacific Ocean continues to produce large quantities of Pacific salmon, temporal abundance patterns vary among species and areas. Currently, pink and chum salmon are very abundant overall and Chinook and coho salmon are less abundant than they were previously, whereas sockeye salmon abundance varies among areas. Analyses confirm climate-related shifts in abundance, associated with reported ecosystem regime shifts in approximately 1947, 1977, and 1989. We found little evidence to support a major shift after 1989. From 1990, generally favourable climate-related marine conditions in the western North Pacific Ocean, as well as expanding hatchery operations and improving hatchery technologies, are increasing abundances of chum and pink salmon. In the eastern North Pacific Ocean, climate-related changes are apparently playing a role in increasing chum and pink salmon abundances and declining numbers of coho and Chinook salmon.
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Zaffos, Andrew, and Steven M. Holland. "Abundance and extinction in Ordovician–Silurian brachiopods, Cincinnati Arch, Ohio and Kentucky." Paleobiology 38, no. 2 (2012): 278–91. http://dx.doi.org/10.1666/10026.1.
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A basic hypothesis in extinction theory predicts that more abundant taxa have an evolutionary advantage over less abundant taxa, which should manifest as increased survivorship during major extinction events and longer fossil-record durations. Despite this, various paleontologic studies have found conflicting patterns, indicating a more complex relationship between abundance and extinction in the geologic past. This study tests the relationship between abundance and extinction among brachiopod genera within seven third-order depositional sequences spanning the Late Ordovician to Early Silurian (Katian–Aeronian) of the Cincinnati Arch.Contrary to predictions, abundance is not positively correlated with duration in this study. Abundance and duration range from strongly negatively correlated to uncorrelated depending on the spatial scale of analysis and the geologic intervals included, but correlations never indicate that abundance is an evolutionary advantage. In contrast, abundance was an advantageous trait prior to the Ordovician/Silurian extinction, and brachiopods with higher abundances were more likely to survive the event than less abundant brachiopods. While this result is in keeping with common models of extinction, it has not been observed previously at a mass extinction boundary. This may be further evidence that the Ordovician/Silurian extinction was not accompanied by a shift in the macroevolutionary selectivity regime.
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Brygadyrenko, Viktor. "Evaluation of ecological niches of abundant species of Poecilus and Pterostichus (Coleoptera: Carabidae) in forests of steppe zone of Ukraine." Entomologica Fennica 27, no. 2 (August 20, 2019): 81–100. http://dx.doi.org/10.33338/ef.84662.
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This article analyses abundances of seven Poecilus and Pterostichus species sampled from 836 forest sites located in five geographical regions of the steppe zone of Ukraine. The abundances are analysed in relation to eight forest conditions. New information about associations of the following five species was found. Poecilus versicolor was most abundant in sparse forest sites and on moist sandy soil. Pterostichus melanarius reached its maximum abundance on sites with a thick litter layer, mesohygrophilous condition, clay soils and a sparse herbaceous layer. Pterostichus niger reached maximum abundance in forests with mesohygrophilous and hygrophilous conditions and on sandy loam soils. Abundance of Pterostichus oblongopunctatus was at the highest on sites with a closed tree canopy, a thin litter layer and loamy soils of average salinity. Pterostichus ovoideus was most abundant in forests with low to average litter depth, hygrophilous conditions and loamy soils oflow to average salinity. For Poecilus sericeus and Poecilus cupreus the results ofthis study agreed with the published information.
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Çalışkan, Şeyma, Elisabetta Caffau, Piercarlo Bonifacio, Luca Sbordone, and Berahitdin Albayrak. "Abundance analysis of three metal poor stars: CS 22166-0030, CS 22186-0005, and CS 30344-0033." Proceedings of the International Astronomical Union 9, S298 (May 2013): 381–86. http://dx.doi.org/10.1017/s1743921313006595.
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AbstractWe present the abundance analysis of three very metal poor stars, CS 22166-0030 ([Fe/H]=−2.96), CS 22186-0005 ([Fe/H]=−2.70), and CS 30344-0033 ([Fe/H]=−2.90). Our study is based on high resolution spectra which were obtained from SARG (on TNG), HARPS (on 3.6m), and UVES (on VLT) spectrographs and one-dimensional ATLAS9 model atmospheres. We derived the abundances for 2, 9, and 16 atomic species in the spectrum of CS 22166-0030, CS 22186-0005, and CS 30344-0033, respectively. The Na and Mg abundances of CS 22166-0030 are highly under-abundant with respect to the solar values. The abundance patterns of CS 22186-0005 and CS 30344-0033 are consistent with the other halo stars within abundance uncertainties.
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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 (July 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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Poulin, R., J. L. Luque, F. Guilhaumon, and D. Mouillot. "Species abundance distributions and numerical dominance in gastrointestinal helminth communities of fish hosts." Journal of Helminthology 82, no. 3 (September 2008): 193–202. http://dx.doi.org/10.1017/s0022149x08982626.
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AbstractThe abundances of different species in a parasite community are never similar: there is typically one or a few numerically dominant species and many species with low abundance. Here, we determine whether basic features of parasite communities are associated with strong dominance by one or a few species, among 39 component communities of gastrointestinal helminths in marine fishes from Brazil. First, we tested whether the shape of the species abundance distribution in these communities fits that predicted by several theoretical models, using a goodness-of-fit procedure. Only the canonical lognormal model could be rejected for 5 out of 39 communities; all other comparisons of observed and predicted abundance distributions showed no significant differences, although this may be due to limited statistical power. Second, we used the ratio between the abundance of the most abundant species and either the second or third most abundant species, as indices of dominance; these show, for instance, that the dominant species in a community is typically twice, but sometimes over ten times, as abundant as the next most abundant species. We found that these ratios were not influenced by either the community's species richness, the mean number of individual parasites per host, or the taxonomic identity of the dominant species. However, the abundance ratio between the first and third most abundant species in a community was significantly correlated with an independent index of species interactivity, based on the likelihood that the different parasite species in a component community co-occur in the same host individuals: the difference in abundance between the dominant and third most abundant species was greater in communities characterized by weak interactions. These findings suggest that strong interactions may lead to greater evenness in the abundance of species, and that numerical dominance is more likely to result from interspecific differences in recruitment rates.
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Navarro-Almaida, D., R. Le Gal, A. Fuente, P. Rivière-Marichalar, V. Wakelam, S. Cazaux, P. Caselli, et al. "Gas phase Elemental abundances in Molecular cloudS (GEMS)." Astronomy & Astrophysics 637 (May 2020): A39. http://dx.doi.org/10.1051/0004-6361/201937180.
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Context. Sulphur is one of the most abundant elements in the Universe. Surprisingly, sulphuretted molecules are not as abundant as expected in the interstellar medium and the identity of the main sulphur reservoir is still an open question. Aims. Our goal is to investigate the H2S chemistry in dark clouds, as this stable molecule is a potential sulphur reservoir. Methods. Using millimeter observations of CS, SO, H2S, and their isotopologues, we determine the physical conditions and H2S abundances along the cores TMC 1-C, TMC 1-CP, and Barnard 1b. The gas-grain model NAUTILUS is used to model the sulphur chemistry and explore the impact of photo-desorption and chemical desorption on the H2S abundance. Results. Our modeling shows that chemical desorption is the main source of gas-phase H2S in dark cores. The measured H2S abundance can only be fitted if we assume that the chemical desorption rate decreases by more than a factor of 10 when nH > 2 × 104. This change in the desorption rate is consistent with the formation of thick H2O and CO ice mantles on grain surfaces. The observed SO and H2S abundances are in good agreement with our predictions adopting an undepleted value of the sulphur abundance. However, the CS abundance is overestimated by a factor of 5−10. Along the three cores, atomic S is predicted to be the main sulphur reservoir. Conclusions. The gaseous H2S abundance is well reproduced, assuming undepleted sulphur abundance and chemical desorption as the main source of H2S. The behavior of the observed H2S abundance suggests a changing desorption efficiency, which would probe the snowline in these cold cores. Our model, however, highly overestimates the observed gas-phase CS abundance. Given the uncertainty in the sulphur chemistry, we can only conclude that our data are consistent with a cosmic elemental S abundance with an uncertainty of a factor of 10.
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Cañete, Juan I., Carlos S. Gallardo, Carlos Olave, María S. Romero, Tania Figueroa, and Daniela Haro. "Abundance and spatial distribution of neustonic copepodits of Microsetella rosea (Harpacticoida: Ectinosomatidae) along the western Magellan coast, southern Chile." Latin American Journal of Aquatic Research 44, no. 3 (February 23, 2017): 576–87. http://dx.doi.org/10.3856/vol44-issue3-fulltext-16.
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The pelagic harpacticoid copepod Microsetella rosea inhabits the cold waters along the temperate southern coast of Chile, where its population biology and ecological role in the neuston are unknown. During a CIMAR 16 Fiordos cruise realized in the Magellan Region, 26 neustonic samples were collected to analyze the abundance, spatial distribution of copepodits and oceanographic conditions (temperature, salinity, and dissolved oxygen). M. rosea copepodits, the most abundant holoneustonic taxa (30% of total abundance), were present at all sampled stations and were 0.5 times more abundant than calanoids. These copepodits inhabited waters ranging between 6.5-8.5°C and salinity of 26-33, with maximum abundances (1,000-10,000 ind/5 min horizontal drag) at means of 7.2 ± 0.6ºC and salinities of 30.7 ± 0.9. Froward Cape, Almirantazgo Sound, and Inútil Bay stations accounted for 65% of total M. rosea abundance, whereas Beagle Channel stations present the lowest abundances (<4%). The entire sampling area was as an oxygenated estuary (7.4 ± 0.4 mL L-1). Given the abundance and recurrence of M. rosea in the Magellanic neuston, future research should assess the ecological functions of this species. Finally, M. rosea could also be used as a biotracer for processes of aggregation in other estuarine neustonic communities of southern Chile.
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Nazarova, Sophia A., Ksenia Shunkina, and Evgeny A. Genelt-Yanovskiy. "Abundance distribution patterns of intertidal bivalves Macoma balthica and Cerastoderma edule at the Murman coast tidal flats (the Barents Sea)." Journal of the Marine Biological Association of the United Kingdom 95, no. 8 (July 15, 2015): 1613–20. http://dx.doi.org/10.1017/s0025315415000624.
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Density distribution of the common infaunal bivalves, Macoma balthica and Cerastoderma edule, was studied along the Murman Coast of the Barents Sea during 2002–2010. In both species, abundance was generally higher in West Murman in contrast to East Murman. Highest density of Macoma balthica reaching 1535 ind. m−2 was observed in the Kola Inlet. Cerastoderma edule was less abundant; its density rarely exceeded 10 ind. m−2 in all but one site, where 282 ind. m−2 was registered. Reconstruction of abundance distribution across the European geographic range of Macoma balthica revealed that it does not match an ‘abundant-centre’ pattern, having features of ramped north. On the other hand, distribution of Cerastoderma edule abundance across the range generally follows an ‘abundant-centre’ pattern but southern edge populations show relatively higher abundances as compared with those at the north edge (the Barents Sea).
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Monier, Richard. "Abundances of Heavy Elements in the B8 Mn Star HD 110073." Research Notes of the AAS 7, no. 10 (October 19, 2023): 218. http://dx.doi.org/10.3847/2515-5172/ad03f4.
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Abstract The synthesis of several spectral intervals in the optical range allows the determination of LTE abundances of strontium, yttrium, zirconium, barium, praseodymium, neodymium, platinum and mercury for this B8 Mn star. Compared to the solar abundances, strontium, yttrium, barium, praseodymium and mercury are found to be overabundant by factors of 2.5, 130, 10, 150 and 60,000. Only upper limits could be determined for zirconium and platinum. The lines of Nd iii are blended with lines of more abundant elements which precludes the determination of the abundance of neodymium. The abundance of manganese, derived from the Mn ii line at 3986.59 Å is about 100 times larger than in the Sun.
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Oghenekaro and Chigbu. "Dynamics of Mesozooplankton Assemblage in Relation to Environmental Factors in the Maryland Coastal Bays." Water 11, no. 10 (October 14, 2019): 2133. http://dx.doi.org/10.3390/w11102133.
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The mesozooplankton composition and dynamics in coastal lagoons of Maryland, mid-Atlantic region, USA have received little scientific attention despite the fact that the lagoons have undergone changes in water quality in the past two decades. We compared mesozooplankton abundance and community structure among sites and seasons, and between 2012, a year of higher than average salinity (33.4), and 2013 with lower than average salinity (26.6). It was observed that the composition, diversity, and abundance of mesozooplankton in 2012 differed from those of 2013. Barnacle nauplii were abundant in 2012 contributing 31% of the non-copepod mesozooplankton abundance, whereas hydromedusae were more dominant in 2013 and contributed up to 83% of non-copepod zooplankton abundance. Gastropod veliger larvae were more abundant in 2013 than in 2012 while larvae of bivalves, polychaetes, and decapods, in addition to cladocerans and ostracods had higher abundances in 2012. The abundance and diversity of mesozooplankton were explained by variations in environmental factors particularly salinity, and by the abundance of predators such as bay anchovy (Anchoa mitchelli). Diversity was higher in spring and summer 2012 (dry year) than in 2013 (wet year). The reduction of salinity in fall 2012, due to high freshwater discharge associated with Hurricane Sandy, was accompanied by a decrease in mesozooplankton diversity. Spatially, diversity was higher at sites with high salinity near the Ocean City Inlet than at sites near the mouth of tributaries with lower salinity, higher nutrient levels and higher phytoplankton biomass. Perhaps, the relatively low salinity and high temperature in 2013 resulted in an increase in the abundance of hydromedusae, which through predation contributed to the reduction in the abundance of bivalve larvae and other taxa.
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Bannister, R. J., R. Brinkman, C. Wolff, C. Battershill, and R. de Nys. "The distribution and abundance of dictyoceratid sponges in relation to hydrodynamic features: identifying candidates and environmental conditions for sponge aquaculture." Marine and Freshwater Research 58, no. 7 (2007): 624. http://dx.doi.org/10.1071/mf07011.
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The distribution and abundance of dictyoceratid sponges was surveyed to a depth of 20 m at eleven locations within the Palm Island Group, Great Barrier Reef (GBR), Australia. These surveys were related to prevailing hydrodynamic conditions to identify candidates and environmental conditions for sponge aquaculture. Locations were classified as sheltered, intermediate and exposed using quantitative wave exposure and current force models. The species richness of dictyoceratid sponges was high with ten taxa, but the abundance of most species was low with patchy distributions. Two species, Coscinoderma sp. and Rhopaloeides odorabile, were abundant, and detailed surveys of these species were conducted at seven locations representing common habitats within the Palm Island Group. Coscinoderma sp. was present at all locations and although abundances differed significantly across locations, this was not related to hydrodynamic conditions. In contrast, R. odorabile was only present at exposed locations with low abundance. The higher abundance and broad distribution of Coscinoderma sp. supports its selection as an aquaculture candidate. In contrast, R. odorabile was less abundant and was restricted to high-energy environments making aquaculture more problematic. The present study demonstrates the importance of ecological data in the decision-making process for new species aquaculture.
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Buen, Lorena López-de, and Juan Francisco Ornelas. "Frugivorous birds, host selection and the mistletoe Psittacanthus schiedeanus, in central Veracruz, Mexico." Journal of Tropical Ecology 15, no. 3 (May 1999): 329–40. http://dx.doi.org/10.1017/s0266467499000851.
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Frugivorous birds play an important role in parasitic mistletoe transmission among host species. The foraging behaviour and host selection of Psittacanthus schiedeanus mistletoe fruit-eating birds was studied in cloud forest remnants in Central Veracruz, México. Cedar waxwings, Bombycilla cedrorum, gray silky-flycatchers, Ptilogonys cinereus, and social flycatchers, Myiozetetes similis, eating ripe whole mistletoe fruits and defecating or regurgitating the seeds were observed. That variation in host species selection by frugivorous birds had a direct effect on mistletoe dispersion was hypothesized. To test whether mistletoe host species are visited in proportion to their abundance (total number of trees), or infested-tree abundance (total number of infested trees), or abundance of mistletoes (total number of individual mistletoe plants in each host species), the number of trees, infested trees and individual mistletoe plants were recorded. Tree abundance, infested-tree abundance and mistletoe abundance were different among host species. Frequency of birds' visits to host species varied depending on the tree, infested-tree, or mistletoe abundance. Liquidambar styraciflua was the most abundant host species with the highest number of infested trees and individual mistletoe plants, but Persea americana and Crataegus mexicana host species had the highest number of individual mistletoe plants in each tree. Our data suggest that L. styraciflua was the most selected host species by the three frugivorous birds. Host selection by birds is one behavioural factor in explaining differences in prevalence among host species, and variation in infection levels among individuals of one host species.RESUMEN. Las aves frugívoras juegan un importante papel en la transmisión de muérdagos parásitos hacia sus árboles hospederos. La conducta de forrajeo y selección de hospedero de aves consumidoras de frutos del muérdago Psittacanthus schiedeanus fueron estudiados en remanentes de bosque mesófilo de montaña del Centro de Veracruz, México. Bombycilla cedrorum, Ptilogonys cinereus and Myiozetetes similis fueron observados consumiendo frutos maduros enteros y defecando o regurgitando las semillas. Hipotetizamos que la variación en la selección de la especie hospedera por las aves frugívoras tiene un efecto directo en la dispersión del muérdago. Para probar si las especies de árboles hospederos son visitadas en proporción a su abundancia (número total de árboles), o la abundancia de hospederos infectados (número de árboles infectados) o la abundancia de muérdagos (número total de plantas individuales de muérdago en una sola especie de árbol); el número de árboles, árboles infestados y plantas de muérdago fueron registradas. La abundancia de árboles, de árboles infestados y de plantas de muérdago fue diferente entre las especies de árboles estudiadas. La frecuencia de visitas de las aves a las especies hospederas varió de acuerdo a la abundancia de árboles, de árboles infestados y de plantas de muérdago. Liquidambar styraciflua fue la especie hospedera más abundante con el mayor número de árboles infestados y abundancia de muérdagos, pero las especies Persea americana y Crataegus mexicana presentaron el mayor número de plantas de múerdago por árbol. Nuestros datos sugieren que L. styraciflua fue la especie hospedera más seleccionada por las aves frugívoras. La selección de hospederos por las aves es uno de los factores conductuales que explican las diferencias en prevalencia entre especies de hospedero, y la variación en los niveles de infestación entre individuos de una de las especies de hospedero.
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Gopalan, Gouthaman, David A. Culver, Lin Wu, and Bruce K. Trauben. "Effects of recent ecosystem changes on the recruitment of young-of-the-year fish in western Lake Erie." Canadian Journal of Fisheries and Aquatic Sciences 55, no. 12 (December 1, 1998): 2572–79. http://dx.doi.org/10.1139/f98-130.
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We compared the variability in forage fish recruitment over the last 27 years against major ecological changes that occurred in Lake Erie over the same time period. During a period of high adult walleye abundance and declining phosphorus loading (1976-1982), we observed a decline in the abundance of later hatching forage fish species (e.g., July) and those species that did not shift their diets from zooplankton to benthos during the summer of their life. During years of high young-of-the-year (YOY) white perch abundance (1983-1990), forage fishes whose hatching dates and (or) diet overlapped with YOY white perch declined in abundance. When the zebra mussel (Dreissena polymorpha) became abundant (1991-1995), most forage fishes showed no change in abundances. Given a YOY's ability to switch to benthos during summer, the date on which this occurred was determined by a combination of zooplankton abundance and fish size. Hence, the dates individual taxa of fish hatch relative to seasonal cycles of zooplankton abundance and the size at which they can undergo an ontogenetic diet shift to benthos and (or) fish could be influencing fish growth and recruitment and need to be incorporated into YOY recruitment models.
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Hidas, Eszter Z., David J. Ayre, and Todd E. Minchinton. "Patterns of demography for rocky-shore, intertidal invertebrates approaching their geographical range limits: tests of the abundant-centre hypothesis in south-eastern Australia." Marine and Freshwater Research 61, no. 11 (2010): 1243. http://dx.doi.org/10.1071/mf09317.
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The abundant-centre hypothesis predicts that species' abundances peak at the centre of their geographical ranges and decline gradually towards their range limits. We tested predictions of this hypothesis for three rocky-shore, intertidal invertebrates with planktonic larvae (the whelk, Morula marginalba, the snail, Afrolittorina pyramidalis, and the barnacle, Tesseropora rosea) by quantifying their patterns of abundance and size, and inferring pulses of recruitment from size-frequency distributions, at multiple spatial scales spanning a 600-km region in south-eastern Australia and encompassing roughly the southern third of their geographical ranges. At the regional scale, abundances for all species were, as predicted, dramatically lower at their range limits. This decline was not gradual, however, because there were large variations in abundance at smaller spatial scales, and abrupt declines at the south-eastern corner of Australia. Size did not change towards the range limit for any species, but size-frequency distributions suggested a decline in the frequency of recruitment events at the range limit for T. rosea. We conclude that the abundant-centre hypothesis is not an appropriate model for abundance distributions of benthic marine invertebrates with planktonic larvae, because of the vagaries of dispersal and recruitment interacting with complex current patterns along non-uniform coastlines.
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Carrick, Hunter J., and Gary L. Fahnenstiel. "Biomass, Size Structure, and Composition of Phototrophic and Heterotrophic Nanoflagellate Communities in Lakes Huron and Michigan." Canadian Journal of Fisheries and Aquatic Sciences 46, no. 11 (November 1, 1989): 1922–28. http://dx.doi.org/10.1139/f89-242.
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The abundance and biomass of surface (5 m) and deep (20–45 m) nanoflagellate communities in Lakes Huron and Michigan were determined during 1987. Abundances (102–103 cells∙mL−1) were comparable between lakes and similar to those reported from other oligotrophic environments. Community composition was skewed towards the small end of the size spectrum due to the prevalence of small chrysomonads. In general, heterotrophic flagellates (Hnano) were more abundant that phototrophic flagellates (Pnano), while standing stocks of Pnano carbon (average 24.7 μg C∙L−1) were greater than Hnano carbon (9.6 μg C∙L−1) on nearly all sample dates. The abundance of nanoflagellates in both Lakes Huron and Michigan peaked in July, perhaps indicating increased growth at higher temperatures and/or a response to higher abundance of prey. Nanoflagellate communities in deep waters during thermal stratification were more abundant (50–70% higher carbon) than surface communities and were dominated by Pnano. High carbon standing stocks of deep communities did not correspond with high prey abundances. Thus, deep communities seem to be influenced by factors (e.g., light and nutrients) that maintain deep phytoplankton communities in the upper Great Lakes. While Hnano are quantitatively important in Lakes Huron and Michigan, representing nearly 20% of phytoplanton biomass, their trophic role is largely unknown.
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Lamarche, C., J. D. Smith, K. Kreckel, S. T. Linden, N. S. J. Rogers, E. Skillman, D. Berg, et al. "Direct Far-infrared Metal Abundances (FIRA). I. M101." Astrophysical Journal 925, no. 2 (February 1, 2022): 194. http://dx.doi.org/10.3847/1538-4357/ac3b4f.
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Abstract Accurately determining gas-phase metal abundances within galaxies is critical as metals strongly affect the physics of the interstellar medium. To date, the vast majority of widely used gas-phase abundance indicators rely on emission from bright optical lines, whose emissivities are highly sensitive to the electron temperature. Alternatively, direct-abundance methods exist that measure the temperature of the emitting gas directly, though these methods usually require challenging observations of highly excited auroral lines. Low-lying far-infrared (FIR) fine structure lines are largely insensitive to electron temperature and thus provide an attractive alternative to optically derived abundances. Here, we introduce the far-infrared abundance (FIRA) project, which employs these FIR transitions, together with both radio free–free emission and hydrogen recombination lines, to derive direct, absolute gas-phase oxygen abundances. Our first target is M101, a nearby spiral galaxy with a relatively steep abundance gradient. Our results are consistent with the O++ electron temperatures and absolute oxygen abundances derived using optical direct-abundance methods by the CHemical Abundance Of Spirals (CHAOS) program, with a small difference (∼1.5σ) in the radial abundance gradients derived by the FIR/free–free-normalized versus CHAOS/direct-abundance techniques. This initial result demonstrates the validity of the FIRA methodology—with the promise of determining absolute metal abundances within dusty star-forming galaxies, both locally and at high redshift.
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Simkanin, Christina, Anne Marie Power, Alan Myers, David McGrath, Alan Southward, Nova Mieszkowska, Rebecca Leaper, and Ruth O'Riordan. "Using historical data to detect temporal changes in the abundances of intertidal species on Irish shores." Journal of the Marine Biological Association of the United Kingdom 85, no. 6 (November 9, 2005): 1329–40. http://dx.doi.org/10.1017/s0025315405012506.
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An historical data set, collected in 1958 by Southward and Crisp, was used as a baseline for detecting change in the abundances of species in the rocky intertidal of Ireland. In 2003, the abundances of each of 27 species was assessed using the same methodologies (ACFOR [which stands for the categories: abundant, common, frequent, occasional and rare] abundance scales) at 63 shores examined in the historical study. Comparison of the ACFOR data over a 45-year period, between the historical survey and re-survey, showed statistically significant changes in the abundances of 12 of the 27 species examined. Two species (one classed as northern and one introduced) increased significantly in abundance while ten species (five classed as northern, one classed as southern and four broadly distributed) decreased in abundance. The possible reasons for the changes in species abundances were assessed not only in the context of anthropogenic effects, such as climate change and commercial exploitation, but also of operator error. The error or differences recorded among operators (i.e. research scientists) when assessing species abundance using ACFOR categories was quantified on four shores. Significant change detected in three of the 12 species fell within the margin of operator error. This effect of operator may have also contributed to the results of no change in the other 15 species between the two census periods. It was not possible to determine the effect of operator on our results, which can increase the occurrence of a false positive (Type 1) or of a false negative (Type 2) outcome.
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Almazán Núñez, Roberto Carlos, Edson Adrián Álvarez Álvarez, Rubén Pineda López, and Pablo Corcuera. "SEASONAL VARIATION IN BIRD ASSEMBLAGE COMPOSITION IN A DRY FOREST OF SOUTHWESTERN MEXICO." Ornitología Neotropical 29 (August 30, 2018): 215–24. http://dx.doi.org/10.58843/ornneo.v29i1.297.
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Abstract · Tropical dry forests are characterized by a marked seasonality throughout the year. The response of bird assemblages and species abundance to the seasonal changes of dry forests, as evidenced by bird feeding habits, can contribute to a greater understanding of the ecological processes in this ecosystem. In this study, we estimated variations in richness, abundance and composition of bird assemblages as well as their main feeding habits during two seasons of the year (dry and rainy) in a tropical dry forest in southwestern Mexico. Visual and auditory sampling was performed from February 2010 to February 2011 with a fixed-radius point count method (123 point counts distributed across nine transects). A total of 82 bird species belonging to 28 families were recorded in the study area. Although we found more species and a higher abundance in the dry season than in the rainy season, only the abundance of insectivorous-frugivorous and omnivorous birds was significantly higher. According to an ordination analysis, the composition and abundance of bird assemblage changed seasonally. A total of 21 resident birds were found in the dry season (March–June). Some omnivorous and granivorous birds, such as Streak-backed Oriole (Icterus pustulatus) and Blackchested Sparrow (Peucaea humeralis), were the most abundant species in both seasons. Other species, such as Western Kingbird (Tyrannus verticalis) and Golden-cheeked Woodpecker (Melanerpes chrysogenys), both insectivorous-frugivorous, were also abundant in two seasons. The greater diversity of avian feeding guilds in the dry season could be influenced by the reproductive activity that occur during this season and by the presence of Bursera fruits, as confirmed in other studies. Resumen · Variación estacional en la composición de ensambles de aves en un bosque tropical seco del suroeste de México Los bosques tropicales secos se caracterizan por una marcada estacionalidad climática a lo largo del año. Comprender la respuesta de los ensambles de aves y la abundancia de las especies de acuerdo a sus hábitos de alimentación, respecto a los cambios estacionales en el bosque seco, contribuye al conocimiento de los procesos ecológicos en este ecosistema. En este estudio, estimamos la variación de la riqueza, abundancia y composición de las aves y sus tipos de dieta en dos estaciones del año (secas y lluvias) en un bosque tropical seco al suroeste de México. Se realizaron muestreos visuales y auditivos durante un año (febrero de 2010 a febrero de 2011), con el uso de puntos de conteo de radio fijo (123 puntos distribuidos en nueve transectos). Se registró un total de 82 especies de aves que pertenecen a 28 familias. La estación seca presentó mayor riqueza de especies y abundancia de aves que la estación lluviosa, pero solo la abundancia de las aves insectívoro-frugívoras y omnívoras fue significativamente mayor en la estación seca. De acuerdo al análisis de ordenación, la composición y abundancia del ensamble de aves cambió estacionalmente. Se encontró un total de 21 aves residentes en los meses secos del año, que corresponde a la temporada reproductiva (marzo–junio). Algunas aves omnívoras y granívoras como la calandria dorso rayado (Icterus pustulatus) y el zacatonero pecho negro (Peucaea humeralis) fueron las más abundantes en ambas temporadas. Otras especies como tirano pálido (Tyrannus verticalis) y carpintero enmascarado (Melanerpes chrysogenys), ambas insectívoro-frugívoras, también fueron abundantes en las dos estaciones. La mayor diversidad de gremios alimenticios de las aves en la estación seca podría estar influenciada por las actividades reproductivas que transcurren durante esta temporada, y por la presencia de frutos de Bursera spp., como se ha observado en otros estudios.
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Leakey, R. J. G., P. H. Burkill, and M. A. Sleigh. "Planktonic ciliates in Southampton Water: quantitative taxonomic studies." Journal of the Marine Biological Association of the United Kingdom 73, no. 3 (August 1993): 579–94. http://dx.doi.org/10.1017/s0025315400033129.
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The species-specific abundance and biomass of marine planktonic ciliates were determined at monthly intervals at two stations in Southampton Water between June 1986 and June 1987. The two stations, an outer one at Calshot and an inner one at north-west Netley, were subject to differing marine and terrestrial influences. A total of 55 ciliate taxa were recorded during the sampling period; of these 34 taxa were identified to genus and 16 to species. The heterotrophic ciliate community at both stations was dominated by aloricate taxa which comprised >90% of the community abundance and biomass during some months. The loricate tintinnids were also common, especially at Calshot, during winter months. Oligotrichs dominated the aloricate community at both stations with haptorids prominent at north-west Netley. At Calshot, Strotnbidium sp. dominated the heterotrophic community abundance and biomass throughout the study period, while Askenasia sp., Strobilidium sp. and Tintinnopsis sp. were also common. Strombidium sp. also contributed most to heterotrophic community abundance at north-west Netley. Balanion sp. and Tintinnopsis sp. were also abundant. However, Cydotrichium sp. and Didiniunt sp. dominated community biomass at this station. Most taxa exhibited a seasonal cycle with low winter and high spring and summer abundances. Some taxa reached abundances of >2000 l1 However, maximum abundance of one species of Tintinnopsis was found during winter months. The autotrophic ciliate, Mesodinium rubrum, was also recorded at both stations achieving densities >105l1 at north-west Netley during ‘bloom’ conditions.
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Nurdin, Muh Saleh, Eniwati Bakri, Teuku Fadlon Haser, and Nur Hasanah. "The relationship between blue swimming crab (Portunus pelagicus) abundance and environmental parameters in Spermonde Archipelago." Tomini Journal of Aquatic Science 1, no. 1 (May 21, 2020): 8–15. http://dx.doi.org/10.37905/tjas.v1i1.5917.
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Management and conservation of the blue swimming crabs by the marine protected area method require the abundance and environmental parameter information of the blue swimming crab. The aim of this study is to analyze the changes in the relative abundance of the blue swimming crab and its environmental parameters. The study was conducted from March to July 2015, in the waters of Salemo Island, Spermonde Archipelago. The specimens were collected at the three fishing locations around the mangrove, seagrass, and coral reef ecosystems. The variable of relative abundance of the blue swimming crab is determined catch per effort. Samples of environmental parameters such as temperature and current speed are measured in situ. However, for the salinity, dissolved oxygen, ammonia, nitrate, plankton, and chlorophyll-a were analyzed in the laboratory. A comparison of the blue swimming crab abundance in each ecosystem was conducted by One Way ANOVA. Moreover, the relationship between blue swimming crab abundance with environmental parameters was analyzed by multiple regression. The results show that the blue swimming crab is abundant in the seagrass and coral reefs. The environmental parameter that significantly influences the abundance of the blue swimming crab is salinity. The suitable area for blue swimming carb protection based on abundances are seagrass and coral reef ecosystems.
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Vincent, Geoffrey P., Justin K. Davis, Matthew J. Wittry, Michael C. Wimberly, Chris D. Carlson, Denise L. Patton, and Michael B. Hildreth. "Epidemic West Nile Virus Infection Rates and Endemic Population Dynamics Among South Dakota Mosquitoes: A 15-yr Study from the United States Northern Great Plains." Journal of Medical Entomology 57, no. 3 (December 4, 2019): 862–71. http://dx.doi.org/10.1093/jme/tjz231.
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Abstract Mosquito surveillance has been conducted across South Dakota (SD) to record and track potential West Nile virus (WNV) vectors since 2004. During this time, communities from 29 counties collected nearly 5.5 million mosquitoes, providing data from over 60,000 unique trapping nights. The nuisance mosquito, Aedes vexans (Meigen) was the most abundant species in the state (39.9%), and most abundant in most regions. The WNV vector, Culex tarsalis Coquillett (Diptera: Culicidae), was the second most abundant species (20.5%), and 26 times more abundant than the other Culex species that also transmit WNV. However, geographic variation did exist between WNV vector species, as well as relative abundance of vector and nuisance mosquitoes. The abundance of Ae. vexans decreased from east to west in South Dakota, resulting in an increase in the relative abundance of Cx. tarsalis. Other species are reported in this study, with various relative abundances throughout the different regions of South Dakota. WNV infection rates of mosquitoes showed that Cx. tarsalis had the most positive sampling pools and the highest vector index of all the species tested. This study addressed the need for an updated summary of the predominant mosquito species present in the United States Northern Great Plain and provides infection rate data for WNV among these predominant species.
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Laudisoit, Anne, Simon Neerinckx, Rhodes H. Makundi, Herwig Leirs, and Boris R. Krasnov. "Are local plague endemicity and ecological characteristics of vectors and reservoirs related? A case study in north-east Tanzania." Current Zoology 55, no. 3 (June 1, 2009): 200–211. http://dx.doi.org/10.1093/czoolo/55.3.200.
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Abstract The pattern of plague endemicity in Tanzania is characterized by continuous re-appearance of the disease in some locations, while in other neighbouring villages the disease has never or seldom been observed. To understand the reasons for this pattern, we studied small mammal and flea species composition, diversity and relative abundances in two plague-endemic and two plague-free locations. We asked (a) whether fleas more abundant in plague-endemic locations differ in their characteristic abundance and the degree of their host specificity from fleas more abundant in plague-free locations and (b) whether hosts most abundant in plague- endemic locations differ in the diversity of their flea assemblages from hosts most abundant in plague-free locations. We characterized (a) each host species by species richness and degree of taxonomic relatedness of its flea assemblages and (b) each flea species by its mean abundance and size, and degree of taxonomic relatedness of its host spectrum and compared their relative abundances between locations. No significant difference between plague- endemic and plague-free locations in either host density or any variable related to flea abundance or diversity was found. However, there was marginally significant effect of taxonomic distinctness of a flea assemblage harboured by a host on its probability to be more abundant in either plague-endemic or plague-free locations. Furthermore, hosts more abundant in plague-endemic locations tended to harbour closely-related fleas. Finally. while opportunistic and specialist fleas were equally distributed in both sets of locations, fleas exploiting distantly-related hosts were found mainly in plague-free locations during the rainy season. We suggest that the observed patterns might arise due to seasonal and spatial differences in local microclimatic conditions and landscape connectivity.
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Dors, Oli L. "Chemical abundances in Seyfert galaxies – VI. Empirical abundance calibration." Monthly Notices of the Royal Astronomical Society 507, no. 1 (July 30, 2021): 466–74. http://dx.doi.org/10.1093/mnras/stab2166.
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ABSTRACT We derived a bi-dimensional calibration between the emission-line ratios $R_{23}= ([\mathrm{ O}\, {\small {\rm II}}]\,\lambda 3726 +\lambda 3729 +[\mathrm{ O}\mathrm{ }\, {\small {\rm III}}]\,\lambda 4959 + \lambda 5007)/\rm H\,\beta$, ${\it P}=[([\mathrm{ O}\, {\small {\rm III}}]\,\lambda 4959+\lambda 5007)/{\rm H}\,\beta ]/R_{23}$ and the oxygen abundance relative to hydrogen (O/H) in the gas phase of Seyfert 1 and 2 nuclei. In view of this, emission-line intensity ratios for a sample of objects taken from the Sloan Digital Sky Survey Data Release 7 measured by the MPA/JHU group and direct estimates of O/H based on Te-method, adapted for active galactic nuclei (AGNs), are considered. We find no variation of R23 observed along the radii of AGNs, which shows that this line ratio is a good oxygen abundance (O/H) indicator for the class of objects considered in this work. The derived O/H = f(R23, P) relation produces O/H values similar to estimations via Te-method in a wide range of metallicities [$\rm 8.0 \: \lesssim \: 12+\log \,(O/H) \: \lesssim \: 9.2$]. Conversely to star-forming regions in the high-metallicity regime, R23 shows a positive correlation trend with O/H in AGNs. This indicates that the hardness of ionizing radiation is not affected by the metallicities in these objects or narrow-line regions are not significantly modified by changes in the spectral energy distribution due to metallicity variations.
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Villaseñor, Nelida R., Luna A. Chiang, Héctor Jaime Hernández, and Martín A. H. Escobar. "CONTRIBUTION OF INFORMAL GREENSPACE TO BIRD CONSERVATION IN CITIES: A COMPARATIVE STUDY ON THE DIVERSITY OF BIRD COMMUNITIES IN VACANT LANDS, URBAN PARKS AND RESIDENTIAL AREAS." Ornitología Neotropical 32, no. 2 (January 6, 2022): 179–87. http://dx.doi.org/10.58843/ornneo.v32i2.751.
Full textAbstract:
Vacant lands are part of the informal greenspace and could maintain native fauna in urban ecosystems. To provide scientific evidence that promotes bird conservation in cities, we compared different bird community attributes among vacant lands, urban parks, and residential areas in the city of Santiago de Chile. For this, we estimated taxonomic diversity in the three land uses, investigated the species richness and abundance (total and native, including three trophic guilds: granivores, insectivores and omnivores) among land-use types, and evaluated the influence of habitat variables on bird species richness and abundance recorded at sites. We found that vacant lands supported a diverse, with low species dominance, species rich and abundant bird community, comprised mainly by native granivorous and insectivorous birds. In contrast, birds with generalist diet (omnivores) reached high abundances in urban parks and residential areas. While parks and residential areas were dominated by a single omnivore species (Turdus falcklandii and the exotic Passer domesticus, respectively), in vacant lands a set of native species reached high abundances. They included granivorous birds (Sicalis luteola, Zenaida auriculata y Zonotrichia capensis) and insectivorous birds (Tachycineta meyeni y Anthus correndera). Sites with larger cover of herbaceous plants exhibited greater richness and abundance of native birds. In addition, sites with larger proportion of their area covered by bare ground exhibited greater abundance of native birds. Our results demonstrate that vacant lands maintain high bird diversity, as well as a high species richness and abundance of native birds with specialized diets (granivores and insectivores), offering new opportunities to conserve biodiversity in cities.
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Roche, Kimberly E., and Sayan Mukherjee. "The accuracy of absolute differential abundance analysis from relative count data." PLOS Computational Biology 18, no. 7 (July 11, 2022): e1010284. http://dx.doi.org/10.1371/journal.pcbi.1010284.
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Concerns have been raised about the use of relative abundance data derived from next generation sequencing as a proxy for absolute abundances. For example, in the differential abundance setting, compositional effects in relative abundance data may give rise to spurious differences (false positives) when considered from the absolute perspective. In practice however, relative abundances are often transformed by renormalization strategies intended to compensate for these effects and the scope of the practical problem remains unclear. We used simulated data to explore the consistency of differential abundance calling on renormalized relative abundances versus absolute abundances and find that, while overall consistency is high, with a median sensitivity (true positive rates) of 0.91 and specificity (1—false positive rates) of 0.89, consistency can be much lower where there is widespread change in the abundance of features across conditions. We confirm these findings on a large number of real data sets drawn from 16S metabarcoding, expression array, bulk RNA-seq, and single-cell RNA-seq experiments, where data sets with the greatest change between experimental conditions are also those with the highest false positive rates. Finally, we evaluate the predictive utility of summary features of relative abundance data themselves. Estimates of sparsity and the prevalence of feature-level change in relative abundance data give reasonable predictions of discrepancy in differential abundance calling in simulated data and can provide useful bounds for worst-case outcomes in real data.
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Powell, Alexis F. L. A. "Effects of Prescribed Burns and Bison (Bos Bison) Grazing on Breeding Bird Abundances in Tallgrass Prairie." Auk 123, no. 1 (January 1, 2006): 183–97. http://dx.doi.org/10.1093/auk/123.1.183.
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Abstract Grassland birds have declined more than any other avian assemblage in North America, with nearly every species showing negative population trends. In the Flint Hills of Kansas, the largest remnant of the tallgrass prairie biome, annual spring burning of rangeland has recently replaced burning every 2–3 years. I examined effects of different burning and bison (Bos bison) grazing regimes on June abundances of seven bird species using a 23-year data set from the Konza Prairie Biological Station. Fire significantly affected the abundances of six of the seven species. Effects varied among species but, notably, four grass-dependent species—Grasshopper Sparrow (Ammodramus savannarum), Henslow’s Sparrow (A. henslowii), Dickcissel (Spiza americana), and Eastern Meadowlark (Sturnella magna)— and the shrub-dependent Bell’s Vireo (Vireo bellii)—were least abundant or absent at sites in the breeding season immediately following burning. Upland Sandpipers (Bartramia longicauda) were most abundant at sites in the season following burning, whereas Brown-headed Cowbirds (Molothrus ater) exhibited no significant response. Bison grazing increased abundance of Upland Sandpiper and Grasshopper Sparrow, nearly eliminated Henslow’s Sparrow, and (in combination with recent fire) lowered the abundance of Dickcissel. Although fire and grazing are natural forces that maintain tallgrass prairie, their action was, until recently, intermittent and patchy, providing grassland birds with a variety of levels of disturbance. If the vast Flint Hills prairie is to serve as a grassland bird stronghold, the region-wide practice of annual burning with intensive grazing must be replaced with alternatives that restore heterogeneity to the landscape. Efectos de las Quemas Programadas y del Pastoreo de los Bisontes sobre la Abundancia de Aves Reproductivas en Praderas de Pasto Alto
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Lourenço, EC, LM Costa, RM Silva, and CEL Esbérard. "Bat diversity of Ilha da Marambaia, Southern Rio de Janeiro State, Brazil (Chiroptera, Mammalia)." Brazilian Journal of Biology 70, no. 3 (August 2010): 511–19. http://dx.doi.org/10.1590/s1519-69842010000300007.
Full textAbstract:
Few sites have been well sampled for bats, and samplings in islands are even scarcer. Therefore, the objectives of the present study were: (1) to list the bat species of Ilha da Marambaia; (2) to compare richness, abundance and biomass of bat guilds found there; (3) to analyse abundance patterns of bat species; and (4) to compare richness, abundance and composition of the bat fauna among different kinds of environment. To capture bats we used mist nets set in five different environments, totalising 3559.2 net-hours, during 37 nights between October 2006 and August 2008. A total of 1,133 captures were accomplished, comprising 34 species from five families. The most abundant species was Molossus molossus. Frugivorous bats exhibited higher richness, abundance and biomass if compared to other guilds. Most species (N = 22) exhibited abundances between 1 to 10% of all captures. Sixteen species were restricted to just one of the environments sampled. The high richness may be attributed to sampling carried out in several environments, and to the capture of insectivorous species over water bodies.
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Mondal, Sandip, Prahlad Sarkar, Amit Singh, Matiyar Rahaman Khan, and Abhishek Mukherjee. "Distribution and community structure of plant-parasitic nematodes and their relationship with some soil properties in betel vine-growing regions of West Bengal, India." Nematology 21, no. 6 (2019): 581–95. http://dx.doi.org/10.1163/15685411-00003237.
Full textAbstract:
Summary The distribution and community structure of plant-parasitic nematodes associated with betel (Piper betle) vine and their relationship with soil chemical properties were investigated in four major growing regions of West Bengal, India. Ordinary kriging method was applied to infer the patterns of spatial distribution of major plant-parasitic nematodes across the growing regions. Meloidogyne and Rotylenchulus were found to be the most abundant genera in betel vine crops in all growing regions. Co-inertia analysis between soil properties and nematode abundance indicated that soil chemical characters significantly affect abundances of plant-parasitic nematodes. The type of betel vine crop (sweet and bitter) also has a significant effect on the abundance of plant-parasitic nematodes, with the highest abundance of Meloidogyne reported from the bitter type of betel crop. Spatial distribution depicted a higher abundance of Meloidogyne throughout the North Bengal growing region. Root-knot and reniform nematodes are two important plant-parasitic nematodes of betel vine that might cause economic yield loss to the growers in West Bengal.
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Amin, Md Ruhul, Shubhati Khisa, Habibur Rahman, Rayhanur Jannat, and Muhammad Badruzzaman. "Seasonal abundance of major sucking and chewing insects of guava." Bangladesh Journal of Zoology 47, no. 1 (June 27, 2019): 97–105. http://dx.doi.org/10.3329/bjz.v47i1.42025.
Full textAbstract:
Seasonal abundances of the sucking insects, namely mealy bug, white fly and scale insects, and chewing insect viz., fruit fly was monitored during September, 2016 to June, 2017 in a guava Psidium guajava orchard. Sucking insect was monitored by weekly observation on the leaves and chewing insect was captured using methyl eugenol trap. The mealy bug, white fly and scale insects were abundant during 4th week of November to 4th week of January and they showed fluctuations in their population. The mealy bug, white fly and scale insects had peak abundance in the 1st week of January, 4th week of November and 1st week of December, respectively. The scale insect revealed significantly higher abundance compared to other sucking insects. Two species of fruit fly, namely Bactrocera tryoni and B. dorsalis were found in the guava orchard and B. tryoni showed significantly higher abundance compared to B. dorsalis both in winter and summer seasons. In winter, B. tryoni reached the peak abundance in the 2nd week of January and their peak abundance in summer occurred in the 1st week of May. The daily mean temperature and relative humidity influenced the abundance of the sucking and chewing insects. Temperature individually contributed 30.0, 59.6, 59.3% abundance and temperature with relative humidity had 34.8, 60.9 and 73.5% abundance on mealy bug, white fly and scale insect, respectively. The effect of temperature on the abundance of fruit fly in winter and summer were 42.6 and 50.3%, respectively and the combined effect of temperature with relative humidity were 68.7% in winter and 61.9% in summer.
Bangladesh J. Zool. 47(1): 97-105, 2019
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Lizama, Maria de los Angeles Perez, Ricardo Massato Takemoto, and Gilberto Cezar Pavanelli. "Influence of the seasonal and environmental patterns and host reproduction on the metazoan parasites of Prochilodus lineatus." Brazilian Archives of Biology and Technology 49, no. 4 (July 2006): 611–22. http://dx.doi.org/10.1590/s1516-89132006000500011.
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One hundred and forty-eight specimens of Prochilodus lineatus (Valenciennes, 1836) were collected on the Upper Paraná River floodplain, Brazil. Kritskyia boegeri presented significant differences in the abundance according to the host stage of gonadal maturity. Ergasilus sp. presented negative correlation between the GSR of the females and parasite abundance. K. boegeri presented negative correlation between the GSR of the males and abundance. Tereancistrum curimba and Saccocoelioides magnorchis occurred in higher abundance in the open lagoons. Rhinonastes pseudocapsaloideum and S. nanii presented higher abundance in the channels and Tylodelphis sp. presented higher abundance in the closed lagoons and in the rivers. K. boegeri and Amplexibranchius sp. presented significant differences in their abundances between the months of the year. Saccocoelioides nanii presented higher abundances in February-March 2000. Only Tylodelphys sp. presented correlation between fluviometric level and abundance and S. nanii presented significant correlation between water temperature and prevalence.
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Tinti, Michele, and Michael A. J. Ferguson. "Visualisation of proteome-wide ordered protein abundances in Trypanosoma brucei." Wellcome Open Research 7 (January 31, 2022): 34. http://dx.doi.org/10.12688/wellcomeopenres.17607.1.
Full textAbstract:
Background: Trypanosoma brucei is a protozoan parasite and etiological agent of human and animal African trypanosomiasis. It has a complex life cycle, but the most studied cellular types are the in vitro cultivated bloodstream- and procyclic-forms. These correspond to the replicating, mammalian host bloodstream-dwelling, slender trypomastigotes and tsetse vector midgut-dwelling procyclic lifecycle stages, respectively. Several proteomics studies have reported the differential abundance of proteins between these in vitro cultivated cell types. However, there are no datasets providing protein abundance, from most to least abundant, within and between both cell types. Methods: We used MaxQuant software 1.6.10.4 to reprocess a recent large-scale proteomics experiment from our laboratory and extracted intensity-based quantifications of the bloodstream and procyclic form proteomes. Results: We created a web interface to visually explore protein abundances within and between the in vitro cultivated T. brucei bloodstream and procyclic form proteomes. Conclusions: The protein abundance visualization tool, searchable by protein name(s) and attribute(s), is likely to be useful to the trypanosome research community. It will allow users to contextualise their proteins of interest in terms of their abundances in the T. brucei bloodstream and procyclic form proteomes.
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Richards, M. H., A. Rutgers-Kelly, J. Gibbs, J. L. Vickruck, S. M. Rehan, and C. S. Sheffield. "Bee diversity in naturalizing patches of Carolinian grasslands in southern Ontario, Canada." Canadian Entomologist 143, no. 3 (June 2011): 279–99. http://dx.doi.org/10.4039/n11-010.
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AbstractThe bee fauna (Hymenoptera: Apoidea) of the Niagara Peninsula, at the eastern end of the Carolinian Zone in Ontario, Canada, is poorly known. From April to October 2003, we studied bee abundance and diversity in set-aside grasslands at Brock University and the Glenridge Quarry Naturalization Site in southern St. Catharines, Ontario. Using three sampling methods (pan traps, sweep nets, and aerial nets), we collected and identified 15 733 specimens of 124 species and morphospecies representing all bee families, except Melittidae, found in North America. Abundance-based diversity estimators suggested bee species richness to be as high as 148 species. There were three seasonal peaks in bee abundance (early spring, late spring, and mid-summer) with a lull in activity shortly after the summer solstice. Several indicators suggested substantial impacts of disturbance on the Niagara bee community, including evidence of high dominance by the most abundant species. Comparison of the sampling methods indicated considerable catch variation among taxa; Halictidae and Apidae were dominant in pan trap samples and in sweep–aerial net samples, respectively. However, bee abundances in pan traps and sweep nets were highly correlated, suggesting that both methods fairly sample local bee abundances.
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Tinti, Michele, and Michael A. J. Ferguson. "Visualisation of proteome-wide ordered protein abundances in Trypanosoma brucei." Wellcome Open Research 7 (February 1, 2023): 34. http://dx.doi.org/10.12688/wellcomeopenres.17607.2.
Full textAbstract:
Background: Trypanosoma brucei is a protozoan parasite and etiological agent of human and animal African trypanosomiasis. It has a complex life cycle, but the most studied cellular types are the in vitro cultivated bloodstream- and procyclic-forms. These correspond to the replicating, mammalian host bloodstream-dwelling, slender trypomastigotes and tsetse vector midgut-dwelling procyclic lifecycle stages, respectively. Several proteomics studies have reported the differential abundance of proteins between these in vitro cultivated cell types. However, there are no datasets providing protein abundance, from most to least abundant, within and between both cell types. Methods: We used MaxQuant software 1.6.10.4 to reprocess a recent large-scale proteomics experiment from our laboratory and extracted intensity-based quantifications of the bloodstream and procyclic form proteomes. Results: We created a web interface to visually explore protein abundances within and between the in vitro cultivated T. brucei bloodstream and procyclic form proteomes. Conclusions: The protein abundance visualization tool, searchable by protein name(s) and attribute(s), is likely to be useful to the trypanosome research community. It will allow users to contextualise their proteins of interest in terms of their abundances in the T. brucei bloodstream and procyclic form proteomes.
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Yu, Miao, Tie Gao, Zhen Liu, and Xinping Diao. "Effects of Dietary Supplementation with High Fiber (Stevia Residue) on the Fecal Flora of Pregnant Sows." Animals 10, no. 12 (November 30, 2020): 2247. http://dx.doi.org/10.3390/ani10122247.
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This study aimed to investigate the effects of different supplementation levels of stevia residues in high-fiber diets on the fecal microorganisms of pregnant sows. Forty-eight first-farrowing Danish Landrace sows with similar weight, age, and due date were randomly divided into four groups. The control group was fed a normal diet (CON; 3.15% crude fiber content), and the treatment groups were supplemented with 20% stevia residue (SRL), 30% stevia residue (SRM), or 40% stevia residue (SRH) stevia residue, with crude fiber content of 7.79%, 9.15%, and 10.68%, respectively. The test period was 135 days, and Illumina Miseq high-throughput sequencing was used to test the fecal bacteria of the pregnant sows on day 56. Compared to the control group, species diversity was greater in the 30% stevia residue group. At the phylum level, Firmicutes and Spirochaetes had the greatest relative abundances; Firmicutes was most abundant in the SRM group, and Spirochaetes was most abundant in the CON group. At the genus level, Lactobacillus, Streptococcus, and Lachnospiraceae_XPB1014_group, and Treponema_2 had the highest relative abundances in the stevia-residue treatments. Among them, Lactobacillus and Treponema_2 were more abundant in SRL, Streptococcus was more abundant in SRH, and Lachnospiraceae_XPB1014_group was more abundant in SRM. Linear discriminant analysis effect size (LEfSe) showed that the bacterial species differed among the stevia residue treatments. SRL mainly included g__Lactobacillus and g__Romboutsi, SRM mainly included g__Lachnospiraceae_XPB1014_group and g__Ruminococcaceae_UCG_014, SRH mainly included g__Streptococcus, and CON mainly included g__Treponema_2, f__Clostridiaceae_1, g__norank_f__Muribaculaceae, and g__norank_f__p_251_o5. Stevia-residue supplementation significantly increased the abundance of beneficial bacteria, such as g__Lachnospiraceae_XPB1014_group, g__Christensenellaceae_R-7_group, and g__Ruminococcaceae_UCG-005 (p < 0.05), and significantly reduced the abundance of harmful bacteria, such as Treponema_2 (p < 0.05). Moreover, compared with the control group, the stevia-residues treatment groups reduced the feed cost 8.33%, 12.50%, and 13.33% per sow per day, respectively. In conclusion, high-fiber diets can improve the intestinal balance and evenness index of the intestinal flora in pregnant sows, promote the relative abundance of beneficial bacteria, reduce the relative abundance of harmful bacteria, and reduce feed cost. The optimal supplementation level of the stevia residue was found to be 30%.
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Auth, TD, T. Arula, ED Houde, and RJ Woodland. "Spatial ecology and growth in early life stages of bay anchovy Anchoa mitchilli in Chesapeake Bay (USA)." Marine Ecology Progress Series 651 (October 1, 2020): 125–43. http://dx.doi.org/10.3354/meps13431.
Full textAbstract:
The bay anchovy Anchoa mitchilli is the most abundant fish in Chesapeake Bay (USA) and is a vital link between plankton and piscivores within the trophic structure of this large estuarine ecosystem. Baywide distributions and abundances of bay anchovy eggs and larvae, and larval growth, were analyzed in a 5 yr program to evaluate temporal and spatial variability based on research surveys in the 1995-1999 spawning seasons. Effects of environmental variability and abundance of zooplankton that serve as prey for larval bay anchovy were analyzed. In the years of these surveys, 97.6% of eggs and 98.8% of larvae occurred in the polyhaline lower bay. Median egg and larval abundances differed more than 10-fold for surveys conducted in the 5 yr and were highest in the lower bay. Within years, median larval abundance (ind. m-2) in the lower bay was generally 1-2 orders of magnitude higher than upper-bay abundance. Salinity, temperature, and dissolved oxygen explained 12% of the spatial and temporal variability in egg abundances and accounted for 27% of the variability in larval abundances. The mean, baywide growth rate for larvae over the 5 yr period was 0.75 ± 0.01 mm d-1, and was best explained by zooplankton concentration and feeding incidence. Among years, mean growth rates ranged from 0.68 (in 1999) to 0.81 (in 1998) mm d-1 and were fastest in the upper bay. We identified environmental factors, especially salinity, that contributed to broadscale variability in egg and larval production.
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Metaxas, Anna, and Julie Davis. "Megafauna associated with assemblages of deep-water gorgonian corals in Northeast Channel, off Nova Scotia, Canada." Journal of the Marine Biological Association of the United Kingdom 85, no. 6 (November 9, 2005): 1381–90. http://dx.doi.org/10.1017/s0025315405012567.
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The distribution and abundance of benthic megafauna in areas known to be inhabited by dense gorgonian coral assemblages were examined at Northeast Channel, off Nova Scotia, Canada, in August 2001. Using a remotely operated vehicle, 1–5 video transects during each of 1–2 dives at each of four sites (Rips, Middle Canyon, Hell Hole West and Hell Hole East) were conducted. The relationships in the structure of biological assemblages at three spatial scales: within transects (10s of metres); between dive locations (100s of metres); and among sites (10s to 100s of kilometres) were explored. The most abundant epibenthic taxa included the gorgonians Primnoa resedaeformis and Paragorgia arborea, several suspension feeders (Actinauge verrilli, Bolocera tudiae, an unidentified anemone and encrusting sponge, Ophiacantha abyssicola), the deposit feeder Porania pulvillus insignus and the predatory Solaster endeca. The basket star Gorgonocephalus arcticus was present only on colonies of Paragorgia arborea. Despite large variability in abundance and assemblage composition among transects and dive locations, clear patterns were observed among sites. Mean abundance of most cnidarians and echinoderms was greatest at Hell Hole West. No gorgonians were found at Hell Hole East. The encrusting sponge was most abundant at the Rips and least abundant at Hell Hole East. Cluster analysis and multidimensional scaling (MDS) indicated that, when abundance was averaged across transects for each dive, the megafaunal assemblages fall into groups of dives that separated by site. These differences among sites are most likely related to variability in the physical environment. The epibenthic megafaunal assemblages were as diverse in the presence as in the absence of gorgonian corals, at least at the abundances that we observed. However, the apparent low recruitment and abundance, combined with small population size make these assemblages particularly vulnerable to perturbations.
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Hernández-Trujillo, Sergio, Gabriela Esqueda-Escárcega, and Ricardo Palomares-García. "Zooplankton abundance variability in Magdalena Bay, Baja California Sur, Mexico (1997-2001)." Latin American Journal of Aquatic Research 38, no. 3 (November 17, 2011): 438–46. http://dx.doi.org/10.3856/vol38-issue3-fulltext-8.
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Zooplankton were studied from 16 oceanographic surveys carried out in Magdalena Bay, Baja California Sur, Mexico, between August 1997 and March 2001. Twenty-six taxonomic groups were identified, the most abundant and frequent of which were copepods and chaetognaths. In 2000-2001, the number of zooplankton groups tended to decrease by 10 to 20. Both zooplankton biomass and copepod abundance declined, unlike chaetognaths, which increased slightly. Fluctuations in zooplankton abundance were independent of the chlorophyll-a concentration, whereas the maximum zooplankton abundances were associated with changes in the sea surface temperature. The seasonal zooplankton abundance cycle in Magdalena Bay indicated that, in winter, the averaged was than 65,000 ind 100 m-3, a value that increased to more than 99,000 ind 100 m-3 in spring, remained around 100,000 ind 100 m-3 in summer, and decreased rapidly to nearly 40,000 ind 100 m-3 in autumn.
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Hirner, Joanna Lynne McGarvie, and Sean P. Cox. "Effects of rainbow trout (Oncorhynchus mykiss) on amphibians in productive recreational fishing lakes of British Columbia." Canadian Journal of Fisheries and Aquatic Sciences 64, no. 12 (December 1, 2007): 1770–80. http://dx.doi.org/10.1139/f07-139.
Full textAbstract:
Stocking lakes with trout to enhance recreational fishing can negatively affect native aquatic species. Our objectives were (i) to compare presence, relative abundance, body size, and developmental stage of amphibians in lakes with and without rainbow trout (Oncorhynchus mykiss) in British Columbia’s southern interior, and (ii) to estimate the size of trout impact for application to amphibian conservation. Presence of long-toed salamander (Ambystoma macrodactylum), Columbia spotted frog (Rana luteiventris), and Pacific treefrog (Pseudacris regilla) was not significantly different between lake types. In contrast, western toad (Bufo boreas) larvae presence and relative abundance were significantly higher in lakes with trout. Relative abundance of salamander larvae was significantly lower in lakes with trout, but hypothesis testing did not provide consistent evidence of significantly lower abundances of spotted frog and treefrog larvae. However, estimated ratios of relative abundance (impact) indicated that larvae of the salamander and two frogs were ≥65% less abundant in lakes with trout. Salamander larvae were significantly smaller in lakes with trout. Although amphibians may currently coexist with trout in our study region, trout stocking policy in British Columbia should consider amphibian conservation because the presence of trout is associated with lower amphibian abundance and body size in individual lakes.
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Härkönen, Salla K., and Jouni Sorvari. "Comparison of ant-associated beetle communities inhabiting mounds of forest-dwelling ants in forests and forest clearings." Canadian Journal of Forest Research 48, no. 8 (August 2018): 881–87. http://dx.doi.org/10.1139/cjfr-2018-0083.
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Red wood ant (Formica rufa group) nests contain a highly diverse community of invertebrates, which is largely due to their abundant resources and regulated microclimatic conditions. Clear-felling, however, causes nest mounds to lose surface layer moisture, thus disrupting their inner stability. To study the effects of clear-felling on ant-associated beetles (myrmecophile and non-myrmecophile), 41 nests of Formica aquilonia Yarrow, 1955 located on three clear-fells and adjacent mature forest stands were sampled, and the beetle communities between these habitats were compared. We investigated how habitat type, nest surface moisture content, nest volume, and isolation affect the community composition, species richness, and abundance of beetles. Beetle community composition or species richness did not markedly differ between clearings and forests, although total abundance was higher in forests. Also, total species richness and abundance and myrmecophile abundance increased with increasing moisture content. Overall, nests with similar moisture content and volume had similar species compositions. Nest volume was negatively correlated with myrmecophile species richness. Nest isolation was not related to species richness or abundance. The lower abundances in clearings could be problematic in the long term, as small populations are more likely to become extinct. To ensure the survival of ants and their associates, small-scale clearings should be preferred.
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Richer, M. G., M. L. McCall, and N. Arimoto. "Oxygen Abundances in Diffuse Ellipticals and the Metallicity-Luminosity Relation for Dwarf Galaxies." Symposium - International Astronomical Union 171 (1996): 439. http://dx.doi.org/10.1017/s0074180900233573.
Full textAbstract:
Using theoretical models of the planetary nebula populations in galaxies, we investigate whether the current oxygen abundances in bright planetary nebulae can be used to predict the oxygen abundance that persisted in the interstellar medium when star formation stopped. In all galaxies, these models predict that a gap develops between the abundances observed in bright planetary nebulae and those that persisted in the interstellar medium when star formation stopped. This abundance gap depends primarily upon the oxygen abundance achieved in the interstellar medium when star formation stopped, though it also has some sensitivity to the history of star formation. The gap is always less than 0.5dex in these models. For the Milky Way, the predicted abundance gap, 0.14dex, is identical to that observed. The abundance gap magnifies the abundance-related differences between diffuse ellipticals and dwarf irregulars found by Richer & McCall (1995, ApJ, 445, 642). Diffuse ellipticals are confirmed to have larger oxygen abundances than similarly luminous dwarf irregulars, and to have larger [O/Fe] ratios than dwarf irregulars with the same oxygen abundance. The simplest explanation for both of these observations is that diffuse ellipticals formed on shorter time scales than dwarf irregulars. Given this difference in the history of star formation, diffuse ellipticals cannot be the faded remnants of dwarf irregulars.
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Fabrizio, Mary C., Jonathan Raz, and Rajesh Ramanath Bandekar. "Using linear models with correlated errors to analyze changes in abundance of Lake Michigan fishes: 1973-1992." Canadian Journal of Fisheries and Aquatic Sciences 57, no. 4 (April 1, 2000): 775–88. http://dx.doi.org/10.1139/f00-020.
Full textAbstract:
We examined annual changes in relative abundance of Lake Michigan fishes using linear models with correlated errors in space and time. Abundance of bloater (Coregonus hoyi), deepwater sculpin (Myoxocephalus thompsoni), slimy sculpin (Cottus cognatus), alewife (Alosa pseudoharengus), and rainbow smelt (Osmerus mordax) was monitored with bottom trawls at 10 discrete depths (between 18 and 110 m) off eight fixed ports from 1973 to 1992. The model describing abundance included fixed effects of year, port, depth, and interaction terms as well as quadratic and cubic effects of year and depth because changes in abundance were not strictly linear. Observed temporal trends in abundance varied with species and depth. Additionally, trends in alewife and slimy sculpin abundances depended on port. Cubic trends in the abundance of bloater and quadratic trends in deepwater sculpin and rainbow smelt abundances were similar among ports, permitting lakewide inferences for these species. Mean bloater abundance was low throughout the 1970s, increased during the 1980s, and reached high levels by 1990. Mean abundances of deepwater sculpin and rainbow smelt increased from 1973 to the mid-1980s and declined thereafter. The linear model with correlated errors can be readily applied to repeated-measures data from other fixed-station fishery surveys and is appropriate for data exhibiting spatial and temporal autocorrelations.
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Su, Adrienne. "Abundance." Prairie Schooner 94, no. 4 (2020): 9–10. http://dx.doi.org/10.1353/psg.2020.0115.
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Downing, Raymond. "Abundance." Family Medicine 52, no. 2 (February 7, 2020): 147–48. http://dx.doi.org/10.22454/fammed.2020.572733.
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Groff, Lauren. "Abundance." Ecotone 7, no. 2 (2012): 232–45. http://dx.doi.org/10.1353/ect.2012.0002.
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Takada-Hidai, M. "Non-Magnetic Anomalous Stars: The Hg-Mn Stars — A Review of Elemental Abundances —." Symposium - International Astronomical Union 145 (1991): 137–47. http://dx.doi.org/10.1017/s0074180900227320.
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Abundance analyses of HgMn stars in these 15 years are compiled to clarify the abundance characteristics. NLTE abundance studies relevant to HgMn stars are also surveyed for the period of these 20 years. Discussions are made on influences of uncertainties in the atmospheric parameters and of NLTE effects upon abundance determinations, and further on establishment of abundances.
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Smith, John-David T. "New neon-abundance results in Galactic WN and WC stars." Symposium - International Astronomical Union 212 (2003): 234–35. http://dx.doi.org/10.1017/s0074180900212187.
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The fast, dense winds which characterize Wolf-Rayet stars obscure their underlying cores, and complicate the verification of evolving core and nucleosynthesis models. A powerful technique for probing WR core evolution involves measuring abundances of wind-borne nuclear processed elements. Neon, in particular, undergoes a remarkable change in abundance during the later stages of a WR star's lifetime. By the end of the WC phase, it becomes the fourth most abundant element, after He, C and O (Maeder 1983).