scholarly journals A review of Sciurus Group studies on the red squirrel (Sciurus vulgaris): presence, population density and colour phases in Lombardy (Italy)

2016 ◽  
Vol 3 (2) ◽  
pp. 27
Author(s):  
Carlo M. Biancardi ◽  
Claudio G. Gnoli
Keyword(s):  
Population Density ◽  
Natural Sciences ◽  
Red Squirrel ◽  
Sciurus Vulgaris ◽  
Population Densities ◽  
Cold Environments ◽  
Master Thesis ◽  
Dark Colour ◽  
Great Production ◽  
Research Centres

During the nineties of the last Century, under the inspiration of Luigi Cagnolaro, it had been founded a “Sciurus group”, within the Research Centres of the Società Italiana di Scienze Naturali. Aim of the group was to start a campaign of researches on red squirrel populations in Lombardy, Italy promoting field master thesis on various topics: colour phases and indirect estimations of population densities. The researches were carried out during 10 years in 5 study areas. An investigation and census with questionnaires were started in parallel, with the collaboration of Forest Guards (CFS), Ecological Guards (GEV) and students of biological and natural sciences. The results were published in Italian or exposed in national and international congresses. This review has the purpose to show and critically discuss the overall results, and make them available to a broader audience. The dark colour phase, in the red squirrel, resulted associated to elevation and conifer woodlands, according to the thermoregulation theory, which consider the dark fur thicker and more suitable in cold environments. Squirrel population densities are subject to periodical fluctuations, in conifer woodlands, due to cones availability. Cone crops are subject to cycle with years of great production followed by years of lean. The recorded squirrel densities are middle-lows, but in line with data from similar environments.

Habitat use and population density of the red squirrel, Sciurus vulgaris meridionalis, in the Sila Grande mountain range (Calabria, South Italy)

2000 ◽  
Vol 67 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Mara Cagnin ◽  
Gaetano Aloise ◽  
Fabiola Fiore ◽  
Vincenzo Oriolo ◽  
Luc A. Wauters
Keyword(s):  
Population Density ◽  
Habitat Use ◽  
Mountain Range ◽  
Red Squirrel ◽  
Sciurus Vulgaris ◽  
South Italy

scholarly journals Densidad poblacional y daños ocasionados por la ardilla Sciurus aureogaster: implicaciones para la conservación de los viveros de Coyoacán, México

2010 ◽  
Vol 14 (1) ◽  
pp. 7 ◽  
Author(s):  
Patricia Mora–Ascencio ◽  
Ángeles Mendoza–Durán ◽  
Cuauhtémoc Chávez
Keyword(s):  
Twentieth Century ◽  
Population Density ◽  
Activity Patterns ◽  
Food Supplement ◽  
Central Mexico ◽  
Red Squirrel ◽  
Population Densities ◽  
Palabras Clave ◽  
Distrito Federal ◽  
Siglo Xx

Resumen: La ardilla roja mexicana (Sciurus aureogaster), aunque es una especie nativa del centro de México, fue introducida en los Viveros de Coyoacán a mediados del siglo XX y desde entonces ha ido habituándose a la presencia humana. En este trabajo estimamos la densidad poblacional de ardillas grises en los Viveros de Coyoacán, describimos sus patrones de actividad a lo largo de un año y cuantificamos los daños que producen en los árboles del parque.  Para estimar la densidad poblacional, se realizaron conteos visuales por transecto lineal y por cuadrantes. Los patrones de actividad fueron evaluados en los transectos lineales. El daño fue evaluado según la causa y la especie de árbol, en 12 parcelas de 400 m², y 13 puntos sobre un trayecto escogido al azar. Encontramos densidades poblacionales relativamente altas, en promedio de 5.9 a 6.5 inds./ha según los métodos de transecto y por cuadrantes, respectivamente. Con estos datos, estimamos entre 254 y 270 ardillas en todo el parque. Presentan dos picos de actividad, uno al amanecer y otro antes del anochecer. Poco más de la mitad (52%) de los árboles muestreados (346) presentaron algún tipo de daño; de éstos el 80 % fueron dañados por vandalismo y por poda, y el 20% restante por ardillas. Estos resultados revelan que es importante que se realicen campañas para no suplementar alimento a las ardillas y/o a otras especies y que exista un programa de capacitación para realizar una correcta poda de los árboles y con ello evitar daños mayores.  Palabras clave: Ardillas, densidad poblacional, patrones de actividad, Viveros de Coyoacán, Distrito Federal.Abstract: The Mexican red squirrel (Sciurus aureogaster), but is a species native to central Mexico, was introduced in the Viveros de Coyoacan mid twentieth century and has since been habituated to human presence. In this paper we estimate the density of gray squirrels in the Viveros de Coyoacan, we describe patterns of activity over a year and quantify the damage occurring in the park trees. To estimate population density, visual counts were performed by transect and quadrant. Activity patterns were evaluated in the transects. The damage was assessed according to the cause and the tree species in 12 plots of 400 m² and 13 points on a path chosen at random. We found relatively high population densities, an average of 5.9 to 6.5 inds. / ha according to the methods of transect and quadrant, respectively. With these data, we estimate between 254 and 270 squirrels in the park. They have two activity peaks, one in the morning and one before sunset. Just over half (52%) of trees sampled (346) had some type of damage and of these 80% were damaged by vandalism and pruning, and the remaining 20% by squirrels. These results show that it is important that campaigns be conducted to avoid the squirrels food supplement and / or other species and that a training program to make a proper pruning of trees and thus prevent further damage.Key words: Squirrel, population density, activity patterns, Viveros de Coyoacan, Distrito Federal. 

Managed parks as a refuge for the threatened red squirrel ( Sciurus vulgaris ) in light of human disturbance

2017 ◽  
Vol 211 ◽  
pp. 29-36 ◽  
Author(s):  
Amy Haigh ◽  
Fidelma Butler ◽  
Ruth O'Riordan ◽  
Rupert Palme
Keyword(s):  
Human Disturbance ◽  
Red Squirrel ◽  
Sciurus Vulgaris

Effects of crop sequence and rainfall on population dynamics of Fusarium solani f.sp. phaseoli in soil

1992 ◽  
Vol 70 (10) ◽  
pp. 2005-2008 ◽  
Author(s):  
Robert Hall ◽  
Lana Gay Phillips
Keyword(s):  
Population Dynamics ◽  
Phaseolus Vulgaris ◽  
Population Density ◽  
Fusarium Solani ◽  
Population Densities ◽  
Total Rainfall ◽  
Colony Forming Units ◽  
Bean Crop ◽  
Previous Summer ◽  
Crop Sequence

Evidence is presented that population dynamics of Fusarium solani f.sp. phaseoli in soil depend on the effects of crop sequence and rainfall on parasitic activities of the pathogen. In a rotation trial started in 1978 and conducted over 14 years, population densities (colony-forming units/g) of the fungus in soil remained below 50 in treatments (fallow, repeated corn, repeated soybean) where the preferred host plant (common bean, Phaseolus vulgaris) was not grown. Where bean was grown every 3rd year or every year, population densities reached 475 and 660, respectively, by 1984. Thereafter, population densities of the fungus fluctuated widely from year to year in both rotation and repeated bean treatments. In the rotation treatment, peaks in population density of the pathogen coincided with the years of bean production. In repeated bean plots between 1985 and 1991, population density of the fungus in June was significantly correlated (r = 0.77, p = 0.04) with total rainfall received during the previous summer (June–August). It is postulated that higher rainfall during the growing season of the bean crop stimulated root growth and root infection, leading to the accumulation of higher levels of potential inoculum in infected tissue and the release of higher levels of inoculum into the soil by the following June. Key words: Fusarium solani f.sp. phaseoli, bean, Phaseolus vulgaris, rainfall, crop rotation.

Population Densities Allowed Around Dutch SEVESO Establishments

2000 ◽  
Author(s):  
G. M. H. Laheij ◽  
B. J. M. Ale ◽  
J. G. Post
Keyword(s):  
Population Density ◽  
The Netherlands ◽  
Individual Risk ◽  
Population Densities ◽  
Planning Policy ◽  
Relative Contribution ◽  
Societal Risk ◽  
Dangerous Substances ◽  
The Individual ◽  
Uniform Population

Abstract In the Netherlands, the individual risk and societal risk are used in efforts to reduce the number of people exposed to the effect of an accident at an establishment with dangerous substances. To facilitate the societal risk planning policy an investigation was carried out for the Dutch SEVESO establishments to investigate the possibility of determining a generic uniform population density for the zone between the individual risk contours of 10−5 and 10−6 per year. The indicative limit for the societal risk at this density was not to be exceeded. Also there was to be enough space left for a significantly higher population density outside the individual risk contour of 10−6 per year. The RORISC methodology and the actual data for the 124 Dutch SEVESO establishments were used to determine the generic uniform population density. Based on the data available it can be concluded that the maximum allowed uniform population density in the zone between the individual risk contours of 10−5 and 10−6 per year is lower than one person per hectare. At this density there is no space left for a higher population density outside the individual risk contour of 10−6 per year. For uniform population densities the relative contribution to the societal risk has been found significant up to the individual risk contour of 10−7 per year.

scholarly journals Loss of Octarepeats in Two Processed Prion Pseudogenes in the Red Squirrel, Sciurus vulgaris

2010 ◽  
Vol 71 (5-6) ◽  
pp. 356-363
Author(s):  
Ole Madsen ◽  
Timothy T. Kortum ◽  
Marlinda Hupkes ◽  
Wouter Kohlen ◽  
Teun van Rheede ◽  
...  
Keyword(s):  
Red Squirrel ◽  
Sciurus Vulgaris

scholarly journals Effects of population density on cauliflower crop (Brassica oleracea L. var. botrytis)

1981 ◽  
Vol 38 (1) ◽  
pp. 1-10
Author(s):  
Keigo Minami ◽  
Ricardo Victoria Fº
Keyword(s):  
Population Density ◽  
Brassica Oleracea ◽  
Plant Population ◽  
Population Densities ◽  
Plant Population Density ◽  
Brassica Oleracea L ◽  
Quality Weight

An experiment was carried out to study the effects of the following population densities cauliflowers (plants per ha): 20,833 (0.60 m x 0.80 m), 25,641 (0.60 m x 0.65 m), ....37.037 (0.60 m x 0.45 m) , 55.555 (.0.60 m x 0.30 m), and 111,111 (0,60 m x 0,15 m) ; variety Snow ball. It was concluded that the effects of plant population density are greater on curd quality (weight and size) than on production per ha. The best plant population density to produce cauliflowers curd for Brazil market is from 20,000 to 25,000 plants/ha while for mini-curd is above 55,000 plants/ha.

Population dynamics and production of a brine shrimp, Parartemia zietziana Sayce (Crustacea : Anostraca), in two salt lakes in westren Victoria, Australia

1977 ◽  
Vol 28 (4) ◽  
pp. 417 ◽  
Author(s):  
R Marchant ◽  
WD Williams
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
Temperature Stress ◽  
Brine Shrimp ◽  
Dry Weight ◽  
Salt Lakes ◽  
Confidence Limits ◽  
Length Frequency ◽  
Population Densities ◽  
The Mean

Quantitative samples of P. zietziana were taken monthly for two years from Pink Lake and Lake Cundare. Shrimps were usually contagiously distributed. To reduce error, samples were stratified resulting in confidence limits of 40-50% for the mean population density. Despite this variability, stable trends emerged, and variation was not so great as to mask significant differences. Length-frequency analyses distinguished cohorts; a regression was established between length and dry weight, enabling growth to be estimated from samples. By combining growth with population densities in Allen curves, production was computed. In Pink Lake and Lake Cundare mean pro- duction was 11.3 and 1.0 g dry weight m-2 year-1 respectively. Generally there were two or three generations per year, but time and extent of recruitment were not predictable. Each generation suffered continuous mortality, the death of young shrimps accounting for most of the production. This mortality remains unexplained; there are no significant predators and salinity and temperature stress would occur only during summer.

Natural Infection of a European Red Squirrel (Sciurus vulgaris) with Francisella tularensis subsp. Holarctica

2021 ◽  
Vol 57 (4) ◽  
Author(s):  
Simone R. R. Pisano ◽  
Sonja Kittl ◽  
Ulrike Eulenberger ◽  
Joerg Jores ◽  
Francesco C. Origgi
Keyword(s):  
Francisella Tularensis ◽  
Natural Infection ◽  
Red Squirrel ◽  
Sciurus Vulgaris ◽  
Tularensis Subsp
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