scholarly journals Does the American mink displace the European polecat? A need for more research on interspecific competition between invasive and native species

2021 ◽  
Vol 67 (4) ◽  
Author(s):  
Marcin Brzeziński ◽  
Aleksandra Zarzycka ◽  
Tom A. Diserens ◽  
Andrzej Zalewski
Keyword(s):  
Native Species ◽  
American Mink ◽  
Mustela Putorius ◽  
Spatiotemporal Scale ◽  
Weak Evidence ◽  
Native Populations ◽  
Show Evidence ◽  
Hunting Bags ◽  
The Mean ◽  
Study Sites

AbstractIntroduced alien species can negatively affect native competitors by reducing their populations or eliminating them from ecosystems. However, studies do not always find evidence for anticipated impacts, and changes in native populations can be difficult to estimate. Interactions between the invasive American mink Neovison vison and native European polecat Mustela putorius have been studied in several countries, but the mink’s impact on polecat populations at a large spatiotemporal scale remains unclear. In the years 1995–2018, we live-trapped mink and polecats at 60 study sites in Poland, and we analysed hunting bags of mink and polecats from the years 2009–2018. During 13,766 trap-nights, we captured 905 individuals. Mink comprised 91.2% and polecats 8.8% of trapped animals. The mean mink and polecat trappability was 6 and 0.6 individuals per 100 trap-nights, respectively. At rivers, polecat and mink trappability were negatively correlated, whereas at lakes, they were not correlated. The sex ratio of trapped polecats was more skewed toward males than that of mink. Mink comprised 63.6% and polecats 36.4% of 59,831 animals killed by hunters. Over 10 years, the numbers of mink shot annually increased slightly, whereas the numbers of polecat decreased slightly. There was a positive correlation between numbers of mink and polecats shot annually. We found weak evidence that at a large spatiotemporal scale, the invasion of mink has led to a decline in polecat numbers. Although the datasets we analysed were based on large samples, they were insufficient to show evidence of competitive interactions between these two mustelids.

The Age of Nonsynonymous and Synonymous Mutations in Animal mtDNA and Implications for the Mildly Deleterious Theory

Genetics ◽  
1999 ◽  
Vol 153 (1) ◽  
pp. 497-506 ◽  
Author(s):  
Rasmus Nielsen ◽  
Daniel M Weinreich
Keyword(s):  
Dna Sequences ◽  
Purifying Selection ◽  
Data Sets ◽  
Deleterious Mutations ◽  
Synonymous Mutations ◽  
Weak Evidence ◽  
Mitochondrial Data ◽  
The Mean ◽  
Excess Number ◽  
Neutral Mutations

Abstract McDonald/Kreitman tests performed on animal mtDNA consistently reveal significant deviations from strict neutrality in the direction of an excess number of polymorphic nonsynonymous sites, which is consistent with purifying selection acting on nonsynonymous sites. We show that under models of recurrent neutral and deleterious mutations, the mean age of segregating neutral mutations is greater than the mean age of segregating selected mutations, even in the absence of recombination. We develop a test of the hypothesis that the mean age of segregating synonymous mutations equals the mean age of segregating nonsynonymous mutations in a sample of DNA sequences. The power of this age-of-mutation test and the power of the McDonald/Kreitman test are explored by computer simulations. We apply the new test to 25 previously published mitochondrial data sets and find weak evidence for selection against nonsynonymous mutations.

scholarly journals Potential Fertilization Capacity of Two Grapevine Varieties: Effects on Agricultural Production in Designation of Origin Areas in the Northwestern Iberian Peninsula

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 961
Author(s):  
J. Antonio Cortiñas Rodríguez ◽  
María Fernández-González ◽  
Estefanía González-Fernández ◽  
Rosa A. Vázquez-Ruiz ◽  
F. Javier Rodríguez-Rajo ◽  
...  
Keyword(s):  
Airborne Pollen ◽  
Germination Rate ◽  
Pollen Viability ◽  
Weather Conditions ◽  
Triphenyl Tetrazolium Chloride ◽  
Tetrazolium Chloride ◽  
The Mean ◽  
Study Sites ◽  
Fertilization Capacity

In the present study, we analyzed the main parameters related with the potential fertilization ability of two grapevine varieties, Godello and Mencía, during the years 2017 and 2018. The research was carried out in two vineyards of the Galician winegrowing Designation of Origin areas of Ribeiro and Ribeira Sacra. Ten vines of each variety were selected for bunch and flower counting, pollen calculations, pollen viability studies by means of aceto-carmine (AC) stain and 2, 3, 5-triphenyl tetrazolium chloride (TTC) methods, and the determination of their germination rate. In all vineyards the 50% fruitset was reached, except for Godello in Cenlle during 2017. The mean coulure value was higher for Godello (40.5%) than for Mencía (31%). Analyzing the pollen production per plant and airborne pollen levels, we observed important discordances between them, which can be due to the influence of weather conditions and be related with self-pollination processes. We found important differences on pollen viability depending on the applied method and variety, with higher values for the AC method than the TTC for both varieties in all study plots, and higher values for Mencía variety than Godello. Regarding germination rates, we observed a marked reduction in 2017 with respect to 2018, in all study sites and for both varieties. The analyzed parameters were useful to explain the different productive abilities of Godello and Mencía varieties in the two studied bioclimatic regions of Ribeiro and Ribeira Sacra.

Galapagos Tortoises and Sea Turtles in Gold Rush-Era California

2014 ◽  
Vol 91 (2) ◽  
pp. 20-39 ◽  
Author(s):  
Cyler Conrad ◽  
Allen Pastron
Keyword(s):  
San Francisco ◽  
Native Species ◽  
Sea Turtles ◽  
Rare Event ◽  
Legal Protection ◽  
Sea Turtle ◽  
Gold Rush ◽  
Late Nineteenth Century ◽  
Scientific Curiosity ◽  
Native Populations

Spotting a sea turtle or Galapagos tortoise on the early wharfs and streets of San Francisco or Sacramento, California during the Gold Rush (1848-1855) would not have been a rare event. Massive population influx into the San Francisco Bay region during this time resulted in substantial impacts to native species and habitats of all taxa, but the demand for food resulted in many resources, turtles and tortoises included, being imported into the cities. Providing a fresh and delectable food source, these terrapin were brought to San Francisco and Sacramento to feed the hungry Gold Rush populous. Their taste, popularity and demand also resulted in small numbers being imported into gold mining towns in the San Joaquin Valley and foothills of the Sierra Nevada’s. Remarkable as this process was, the consumption and importation of both sea turtles and Galapagos tortoises during the Gold Rush pushed native populations of these species to the brink of extinction during the mid to late-nineteenth century. Declining numbers of terrapin and increased scientific curiosity, with a desire to safeguard these creatures for future generations, resulted in their eventually legal protection and conservation. In many ways the impacts of the decimation of terrapin in the eastern Pacific during the Gold Rush are still felt today, as conservation and breeding efforts continue in an attempt to return native turtle and tortoise populations to pre-Euro-American contact levels. This research describes the historical, and new archaeofaunal, evidence of the terrapin import market in San Francisco, Sacramento and beyond during the dynamic period of the California Gold Rush.

scholarly journals Resource Utilization and Costs of Care prior to ART Initiation for Pediatric Patients in Zambia

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Hari S. Iyer ◽  
Callie A. Scott ◽  
Deophine Lembela Bwalya ◽  
Gesine Meyer-Rath ◽  
Crispin Moyo ◽  
...  
Keyword(s):  
Pediatric Patients ◽  
Blood Chemistry ◽  
Full Blood Count ◽  
National Guidelines ◽  
Art Initiation ◽  
Time To Initiation ◽  
The Mean ◽  
Study Sites ◽  
Cd4 Percentage ◽  
Mean Cost

Objective. We estimated time to initiation, outpatient resource use, and costs of outpatient care during the 6 months prior to ART initiation for HIV-infected pediatric patients in Zambia.Methods. We enrolled 1,102 children who initiated ART at <15 years of age between 2006 and 2011 at 5 study sites. Of these, 832 initiated ART ≤6 months after first presenting to care at the study sites. Data on time in care and resources utilized during the 6 months prior to ART initiation were extracted from patient medical records. Costs were estimated from the provider’s perspective and are reported in 2011 USD.Results. For the patients who initiated ART ≤6 months after presenting to care, median age at presentation to care was 3.9 years; median CD4 percentage was 13%. Median time to ART initiation was 26 days. Patients made, on average, 2.38 clinic visits prior to ART initiation and received 0.81 CD4 tests, 0.74 full blood count tests, and 0.49 blood chemistry tests. The mean cost of pre-ART care was $20 per patient.Conclusions. Zambian pediatric patients initiating ART ≤6 months after presenting to care do so quickly, utilize fewer resources than mandated by national guidelines, and accrue low costs.

scholarly journals Changing Microarthropod Communities in Front of a Receding Glacier in the High Arctic

Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 226 ◽  
Author(s):  
Dariusz J. Gwiazdowicz ◽  
Bogna Zawieja ◽  
Izabella Olejniczak ◽  
Piotr Skubała ◽  
Anna K. Gdula ◽  
...  
Keyword(s):  
Dominant Species ◽  
Diversity Index ◽  
Rapid Change ◽  
High Arctic ◽  
Soil Characteristics ◽  
Landscape Scale ◽  
Soil Samples ◽  
Pioneer Species ◽  
The Mean ◽  
Study Sites

This study was carried out at Ny-Ålesund on Spitsbergen in Svalbard (High Arctic). Eight study sites were established along a transect from the fjord to the snout of the glacier. The sites differed from each other by the type of vegetation cover and soil characteristics. Soil samples were collected and placed in Tullgren funnels. Extracted arthropods were represented by two groups of mites (Mesostigmata and Oribatida) and springtails (Collembola). The pioneer species that occurred first after retreat of the glacier were representatives of the Collembola (Agrenia bidenticulata and Hypogastrura concolor). Later, other springtails appeared including Folsomia alpha, Folsomia quadrioculata, Hypogastrura concolor, Isotoma anglicana, Sminthurinus concolor and the first species of oribatid mites; Camisia foveolata and Tectocepheus velatus velatus. Arthropod communities recorded along the transect were characterized by large variations in both species composition and abundance of individuals. The greater the distance from the glacier snout, the greater the species richness (2 to 22 species). The mean number of species per sample was the lowest at site 8 (1 ± 0.71) (the closest to the glacier) and greatest at site 1 (14 ± 1.41) (furthest from the glacier). The Simpson’s diversity index (D) was distinctly greater at sites 1 (4.61 ± 0.06) and 3 (3.94 ± 0.11) than at other sites, especially site 8 (1.07 ± 0.06). Densities were least in the samples closest to the glacier (30 to 101 individuals; density 3000–10,100 individuals/m2). At the other locations, abundance was highly variable (905 to 7432 individuals; density 90,500–743,200 individuals/m2). The mean abundances were greatest at sites 2 and 3. The great variations in total abundances observed were often due to the presence or absence of one or more dominant species exhibiting extreme abundance variability between sites. The microarthropod community of the High Arctic is composed of heterogeneous circumpolar species, yet on a landscape scale is extremely dependent on local environmental conditions which may be subject to rapid change.

Euphausiids in the Coral and Tasman Seas during May 1972, I. Horizontal and Vertical Distribution

1979 ◽  
Vol 30 (5) ◽  
pp. 551 ◽  
Author(s):  
FB Griffiths
Keyword(s):  
Mouth Opening ◽  
Migration Pattern ◽  
Night Time ◽  
Migration Patterns ◽  
Diel Migration ◽  
Show Evidence ◽  
The Mean ◽  
Time Periods ◽  
First Time ◽  
Horizontal And Vertical Distribution

Thirty-three species belonging to seven genera of euphausiids were collected at two stations, 20� S.,153� E. and 33� 40'S.,153� E., during May 1972 off the east Australian coast. In all, 33 hauls at the northern station and 21 at the southern station were made with a mouth-opening-losing Tucker trawl at various depths between the surface and 400 m. The hauls were grouped into four time periods: dawn (0401-1000 h), noon (1001-1600 h), dusk (1601-2000 h) and midnight (2001-0400 h). The mean number of euphausiids of all species was 20.78 per 1000 m³ at 33� 40's. and 18.34 per 1000 m³ at 20%. Night-time abundances were greater than day-time abundances at both stations. Twenty-five species were found at the northern station and 29 species at the southern station. Four species, Thysanopoda astylata, T. obtusifrons, T. monacantha, and Nernatoscelis atlantica, were found only at the northern station and eight species, Thysanopoda acutifrons, T. orientalis, Pseudeuphausia latifrons, Euphausia recurva, E. pseudogibba, E. similis variety armata, E. spinifera, and Nematoscelis megalops were found only at the southern station. Euphausia similis is reported from 20� CS..153� E. for the first time. The abundance of 14 species was large enough to allow examination of their diel migration patterns. Only one, Stylocheiron abbreviatum; did not show evidence of a diurnal migration pattern. Thysanoesa gregaria exhibited a probable reversed-migration pattern.

Developing a census method based on sight counts to estimate rabbit (Oryctolagus cuniculus) numbers

2003 ◽  
Vol 30 (5) ◽  
pp. 487 ◽  
Author(s):  
Dylan W. Poole ◽  
Dave P. Cowan ◽  
Graham C. Smith
Keyword(s):  
Population Size ◽  
Field Trials ◽  
Population Estimates ◽  
Economic Costs ◽  
Natural Conditions ◽  
Commercial Farms ◽  
The Mean ◽  
The Difference ◽  
Study Sites ◽  
Autumn And Winter

A rabbit-census method, based on systematic counts conducted at night or at dawn and dusk, was developed and validated in terms of estimating the total number of rabbits present in a given area. Initially, models were developed under semi-natural conditions to describe the relationships between the numbers of rabbits counted and population size. Confidence limits were also calculated. The models were developed by comparing rabbit counts with the actual number of rabbits present, from a known population of animals. Only spotlight counts at night were considered reliable enough to estimate rabbit population size. During the autumn and winter months these represented ~60% of the population present. The model was subsequently validated, in two different exercises, following a series of field trials conducted under a variety of conditions on commercial farms. Initially, population estimates derived from the model were compared with those calculated using an alternative census technique. Population estimates, using the two techniques, were very similar at nine of the ten study sites. A second validation exercise was also conducted whereby the number of rabbits removed at each of the sites was compared with the difference between the mean pre- and post-removal spotlight counts. The results further supported the proposition that spotlight counts represent ~60% of the population present, with the difference between the two mean spotlight counts representing 61.2% (± 11.0, s.d.) of the number of rabbits removed. The census method therefore shows considerable promise as a means to estimate rabbit numbers under a range of agricultural conditions and therefore has the potential to predict accurately the economic costs of rabbit damage and also to gauge the effectiveness of various methods of rabbit control.

scholarly journals Are Voids Present in the Lyman-Alpha Forest?

1988 ◽  
Vol 130 ◽  
pp. 569-569
Author(s):  
Arlin P. S. Crotts
Keyword(s):  
Nearest Neighbor ◽  
Gap Size ◽  
Lyman Alpha ◽  
Broad Absorption Line ◽  
Galaxy Distribution ◽  
Lyman Alpha Forest ◽  
Show Evidence ◽  
The Mean ◽  
Instrumental Bias ◽  
Random Fluctuations

SummaryIf voids like those seen in the low z galaxy distribution existed in the H I distribution at z ≈ 2, then high quality QSO spectra, with many Ly-α forest lines per unit z, could be used to discern the voids from the usual random fluctuations in observed number density of lines (≡ n). Several such spectra have been obtained, and these show evidence for gaps in the Ly-α distribution on scales of 20 to 50 h−1Mpc (comoving coordinates, with h = H0/66.7 km s−1Mpc−1, assuming q0 = 0.1). These results are summarized in the table below. All QSO spectra with a line-of-sight n of Ly-α lines n > 80 per unit z and total number of lines N > 40 known to the author are included (except that of PKS 2000-330 [c.f. Carswell and Rees 1987], which is broken into five separate segments of Ly-α forest by gaps in the data and a broad absorption line). Excluded are portions of these spectra where n falls more than 25% below the mean due to instrumental bias. For each of these the distribution of gaps between nearest-neighbor Ly-α redshifts is computed as a function of gap size. If the distribution of redshifts were Poisson, the distribution of gaps should be a decreasing exponential function of gap size. For the two best spectra, large deviations from an exponential are found in the range of 20 to 50 h−1Mpc (in the other four cases, it should be noted that a large number of gaps of such sizes are still expected from Poisson fluctuations). The probability that such deviations are statistically consistent with an exponential distribution is shown in the fifth column of the table.

scholarly journals The X-ray Emission of Quasars as Observed by Ginga

1994 ◽  
Vol 159 ◽  
pp. 123-125
Author(s):  
A.J. Lawson ◽  
M.J.L. Turner
Keyword(s):  
Spectral Index ◽  
Rest Frame ◽  
Line Emission ◽  
Adequate Description ◽  
Rank Tests ◽  
X Ray ◽  
Spectrum Radio ◽  
Show Evidence ◽  
The Mean ◽  
The Relationship

We present preliminary results on a spectal analysis of quasars observed by the X-ray observatory Ginga. Simple power-law models with fixed Galactic absorbtion provide an adequate description of the spectra for most of the sources in the 2–18 keV band. A small number of sources show evidence for a feature at 6.4 keV (in the source rest frame) due to Fe line emission. Maximum likelihood and Spearman rank tests were used to investigate the relationship between radio loudness and X-ray spectral index in this class of object. These tests showed, respectively, that the mean X-ray spectral index of radio quiet quasars (RQQs) is significantly different from that of flat spectrum radio loud quasars (FRSQs) at the >99% level, and that the dominant relationship with spectral index is radio loudness (not X-ray luminosity or redshift) at >99% significance. This last result has not previously been demonstrated in this band, but agrees with findings in the lower energy Einstein band (0.5–3.5 keV). These results are discussed in the context of current unified models.

scholarly journals Multicentre feasibility of multiple-breath washout in preschool children with cystic fibrosis and other lung diseases

2020 ◽  
Vol 6 (4) ◽  
pp. 00408-2020
Author(s):  
Mirjam Stahl ◽  
Cornelia Joachim ◽  
Ines Kirsch ◽  
Tatjana Uselmann ◽  
Yin Yu ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Preschool Children ◽  
Lung Diseases ◽  
End Point ◽  
Multiple Breath Washout ◽  
Training Quality ◽  
Central Coordination ◽  
The Mean ◽  
Study Sites ◽  
Central Data

BackgroundMultiple-breath washout (MBW)-derived lung clearance index (LCI) detects early cystic fibrosis (CF) lung disease. LCI was used as an end-point in single- and multicentre settings at highly experienced MBW centres in preschool children. However, multicentre feasibility of MBW in children aged 2–6 years, including centres naïve to this technique, has not been determined systematically.MethodsFollowing central training, 91 standardised nitrogen MBW investigations were performed in 74 awake preschool children (15 controls, 46 with CF, and 13 with other lung diseases), mean age 4.6±0.9 years at investigation, using a commercially available device across five centres in Germany (three experienced, two naïve to the performance in awake preschool children) with central data analysis. Each MBW investigation consisted of several measurements.ResultsOverall success rate of MBW investigations was 82.4% ranging from 70.6% to 94.1% across study sites. The number of measurements per investigation was significantly different between sites ranging from 3.7 to 6.2 (p<0.01), while the mean number of successful measurements per investigation was comparable with 2.1 (range, 1.9 to 2.5; p=0.46). In children with CF, the LCI was increased (median 8.2, range, 6.7–15.5) compared to controls (median 7.3, range 6.5–8.3; p<0.01), and comparable to children with other lung diseases (median 7.9, range, 6.6–13.9; p=0.95).ConclusionThis study demonstrates that multicentre MBW in awake preschool children is feasible, even in centres previously naïve, with central coordination to assure standardised training, quality control and supervision. Our results support the use of LCI as multicentre end-point in clinical trials in awake preschoolers with CF.

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