Wyniki wyszukiwania - AGRO

1

Selected elements of the biology of ruffe [Gymnocephalus cernuus L.] of the Vistula Lagoon

100%

Rychter A.

Bulletin of the Sea Fisheries Institute

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1997

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nr 2

2

Age structure of compact sawing machines used for logging

100%

Kusiak W., Gorycki D.

Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria

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2006

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tom 05

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nr 2

3

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Seasonal changes of age structure in a population of Arianta arbustorum (Linnaeus, 1758)

86%

Prockow M., Kuznik-Kowalska E.

Folia Malacologica

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2012

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tom 20

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nr 1

4

Variation in the fecundity of roe deer in Britain: effects of age and body weight

86%

Hewison A. J. M.

Acta Theriologica

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1996

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tom 41

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nr 2

This paper investigates variation in female fecundity in relation to effects of age and body weight within and between 15 populations of roe deer Capreolus capreolus (Linnaeus, 1758) in Britain. Analyses were based on carcass material and fecundity was assessed from the presence/absence and number of fertilised ovulations (.corpora lutea) and implanted foetuses. A significant proportion (> 10%) of does ovulated in their first year in some populations, but such precocious reproductive activity rarely resulted in successful implantation of a foetus. Generally, the majority of yearling does (in their second year) conceived successfully, but average potential litter size was lower than among older animals. There was no consistent age-related variation in fecundity among does older than 2 years. Differences in fecundity between age and body weight classes suggest weight thresholds may exist for the onset of puberty and for successful conception as an adult. Fecundity of adults and yearlings was highly variable between populations and in some populations was considerably lower than previously reported for this species. Although differences between populations were correlated with differences in body weight, this relationship was insufficient to explain the wide variation in fecundity across Britain, suggesting fecundity body weight thresholds will be defined independently in separate populations.

5

Influence of age structure on the determination of the main felling high

86%

Zihlavnik A.

Roczniki Akademii Rolniczej w Poznaniu. Leśnictwo

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2001

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tom 39

6

Demography, density, and survival of an endemic and near threatened cottontail Sylvilagus cunicularius in Central Mexico

86%

Gonzales J., Lara C., Vazquez J., Martinez-Gomez M.

Acta Theriologica

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2007

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tom 52

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nr 3

A 3-year live trapping investigation was carried out in a temperate forest in central Tlaxcala, México from 2002 to 2004. During a total of 504 trap nights, 87Silvilagus cunicularius Waterhouse, 1848 individuals were captured and marked, and age-specific survival models using demographic parameters were tested using the JOLLYAGE program. We evaluated population density of this species over a 1-year period. The age structure of the population varied among years, and the proportion of adults was relatively constant among years, whereas the proportion of juvenile showed high fluctuations. The sex ratio of juveniles that were recaptured as adults, did not differ from unity neither did the sex ratio for adults. We found no sex bias among cottontails during all 3 years of the study. When data for both sexes were combined, mean survival probability of juveniles was lower than that of adults. Although our line transect counts showed a mean density of 27 ± 5.4 individuals per km2, the obtained results from trapping suggests that this species is low in abundance at La Malinche. Further studies are needed to evaluate demographical aspects of this species at different protected and unprotected areas to obtain robust information about their status.

7

Effect of environmental conditions on the populations of Luronium natans [L.] Raf.

86%

Bazydlo E.

Polish Journal of Ecology

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2004

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tom 52

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nr 2

The structure (aggregations` distribution, density, age structure) of Luronium natans L. (Raf.) populations has been studied in 21 lakes in the Pomeranian Lakeland (NW Poland), where the highest population density of this species is found in slightly acid (pH 6–7) waters, poor in DOC (<6.0 mg C dm⁻³) and phosphorus (<30.0 µg TP dm⁻³). Luronium natans reproduces mainly vegetatively and prefers shallow (1–2 m), mineral-organic (5.1–10.0% C) substrates. Seedlings represent about 10% of a population. High levels of pH (pH>8.0), concentration of carbon (>6.0 mg C dm⁻³) and phosphorus (>30.0 µg TP dm⁻³) impede the population growth. Under such conditions population density may be lower by as much as 80–90%, aggregation size smaller, and the proportion of generative stems higher. Luronium natans aggregation size depends on the depth: the deeper the location – the larger and denser the aggregation, the shallower the location – the larger the fraction of generative individuals (up to 98% of the population).

8

The influence of shoot harvesting on the age structure of Convallaria majalis L. populations

86%

Kosinski I.

Acta Societatis Botanicorum Poloniae

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2003

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tom 72

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nr 1

This paper presents the structure of developmental stages and the age structure of Convallaria majalis L. populations. The investigation material consisted of individuals and modules from populations in Betulo-Quercetum, Fago-Quercetum, Melico-Fagetum and Tilio-Carpinetum, in which the leaves and inflorescence of C. majalis were cut annually over a period of three years. Fifty percent of the C. majalis regional population consisted of mature modules, 20% of juvenile modules, 25% of senile modules and a very small percentage of generative modules. In populations of Fago-Quercetum there are four times more senile modules than juvenile modules, while in Melico-Fagetum the percentage of juvenile modules is four times more numerous than the percentage of senile modules. The average age of modules is 4.7±3.8 years. Three year old individuals dominate in the population, while 10 year or older individuals are very rare. In the population disturbed by the three raw material collections, the percentage of juvenile modules was decreased by 50% and the percentage of generative modules was nonexistent. As a result, the average module age is higher than in the undisturbed population. Cutting leaves and inflorescence is an important factor in limiting the recruitment of juvenile modules. The growth of individuals in the disturbed population occurs among older modules, which were able to reproduce before the disturbance occurred. Young individuals (three to four years old) are less numerous in the disturbed population, and the majority of individuals are three to six years old.

9

Urban renewal in Rotterdam and Amsterdam: population consequences

86%

Driessen B. G. J., Ter Welle-Heethuis J. G. P.

Geographia Polonica

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1993

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tom 61

10

Evaluation of age structure of mature forest stands

86%

Marusak R.

Roczniki Akademii Rolniczej w Poznaniu. Leśnictwo

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2001

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tom 39

11

Age structure and reproduction rates of the ring-necked pheasant (Phasianus colchicus L.) population in agricultural landscape (Czech Republic)

72%

Zika T., Salek M., Hola M., Hanzal V., Hart V., Kusta T., Jezek M.

Polish Journal of Ecology

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2014

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tom 62

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nr 4

Detailed knowledge of demographic parameters (such as age structure and reproduction rates) is crucial for guiding conservation and management decisions regarding wildlife populations. Such parameters of wild ring-necked pheasant populations in the current agricultural landscape remain very poorly described. We researched age structure and reproduction rates of predominantly wild populations of the ring-necked pheasant (Phasianus colchicus L.) across the intensively managed agricultural landscape of the Czech Republic. The study area is influenced only marginally by hand-reared pheasants (i.e. as shown by comparison of the average number of released individuals in the study area: 0.3 ♂/yr/1km2 and 0.9 ♀/yr/1km2 and average number of released individuals and harvested in the study area: 8.6 ♂/yr/1km2) and there is a long-term huntable pheasant population. To determine the age of individuals, we used proximal primary feather shaft diameters of 1487 feather samples from males hunted between 2009 and 2011. Moreover, we evaluated the age structure of females as well as both sexes together based on the sex ratio and annual game census. We found a relatively high proportion of adults in the population in comparison with other studies. However, the number of adults decreased throughout the years: 2009 (♂ 44.7%; ♀ 69.5%; ♂♀ 60.7%), 2010 (♂ 35.2%; ♀ 61.3%; ♂♀ 51.5%), 2011 (♂ 29.8%; ♀ 57.4%; ♂♀ 47.0%). The decrease of adults went hand in hand with increase of juveniles and reproduction rates of the study population: 2009 (♂ 124%; ♀ 44%; ♂♀ 65%), 2010 (♂ 184%; ♀ 63%; ♂♀ 94%), 2011 (♂ 236%; ♀ 74%; ♂♀ 113%). Only males were hunted in the study area so we determined higher proportions of females in population for all years. This is the main reason why the reproduction rate of females was lower in percentage expression. Generally, our results showed lower productivity of pheasants in the Czech agricultural landscape in comparison with earlier published studies conducted in the US and UK. However, these studies were published many years ago and thus do not reflect the actual environmental conditions and changes which took place recently (i.e. agricultural intensification).

12

Effects of an exceptionally snowy winter on chamois survival

72%

Rughetti M., Toigo C., Von Hardenberg A., Rocchia E., Festa-Bianchet M.

Acta Theriologica

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2011

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tom 56

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nr 4

Although weather-induced mass mortalities of wild ungulates have been reported, no study has quantified how these episodes may affect the survival of prime-aged adults. Long-term studies of marked ungulates have instead consistently found very weak or no effects of weather on the survival of this age class, particularly for females. We report on the effects of the exceptionally snowy winter of 2008–2009 on three populations of chamois in the western Alps: two in Italy, one in France. In the Alpi Marittime Natural Park in Italy, mortality of prime-aged females (aged 2–9 years) was 43%, about five times higher than reported by previous studies of chamois. Just across the continental divide in the adjacent Mercantour National Park (PNM) in France, however, prime-aged female mortality was only 6%. Senescent females suffered very high mortality in both populations (100% and 56%). In the Gran Paradiso National Park in Italy and in the Alpi Marittime Natural Park, adult male mortality rate was respectively of 81% and 44%, whereas in the PNM, it was only 10%. A recent reduction in population density in the French population, or lower absolute snowfall than in Italy, may explain the difference in survival. Survival of males and prime-aged females can be affected by exceptional weather events, possibly in combination with high population density. Adult chamois of both sexes appeared to show elevated mortality in response to harsh winter conditions. Our results underline the importance of considering sex and age classes in evaluating the impacts of population density in wild ungulates.

13

Effects of land use changes on surface runoff

72%

Chmelova R., Sarapatka B., Pavka P.

International Journal of Ecohydrology and Hydrobiology

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2006

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tom 06

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nr 1-4

97-103

14

Life history pattern of the Bitterling Rhodeus amarus (Bloch, 1782) in Siahroud River (southern Caspian Sea- Iran)

72%

Patimar R., Seifi T., Farahi A., Ezzati M.

International Journal of Ecohydrology and Hydrobiology

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2010

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tom 10

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nr 1

A total of 272 specimens of R. amarus caught in Siahroud River at the southern Caspian Sea from March 2006 to February 2007 were examined for life history attributes. Length-at-age was different between sexes. The von Bertalnffy growth function fit to backcalculated size at age data were: Lt= 94.16 [1-e-0.31(t+0.321)] and Lt=92.33[1-e-0.32(t+0.488)] for males and females respectively. WLR was estimated as W=0.0074TL3.4546 for males and W=0.0133TL3.0550 for females, positive allometric for both sexes. There was no significant difference from parity in the overall sex ratio. The reproductive season is extended from March to June, with a culmination point in April. Two kinds of eggs were found; small eggs measuring between 0.42 and 0.91mm with a mean value of 0.57±0.08, and large yolk-filled eggs ranged from 0.88 to 2.20mm with a mean value of 1.49±0.24 (S.D.). The average absolute and relative fecundities were 329.74 eggs and 187.40 eggs g-1 respectively. Variability of life history patterns of the fish in the basin could be interpreted as species response to basin condition.

15

Analysis of selected biometric features and population attributes of wild boar in the Zielonka Game Investigation Centre

72%

Skubis J., Labudzki L., Gorecki G., Wlazelko M.

Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria

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2009

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tom 08

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nr 3

The authors analysed selected biometric features of the wild boars harvested in the Zielonka Game Investigation Centre in 2004-2007, including the carcass weight, body length and height at the withers, with regard to age and sex. Some population attributes were also analysed, including age, sex and social structure.

16

Growth and formation of Scots pine stands in Eastern Polissia of Ukraine

72%

Zhezhkun A. M.

Folia Forestalia Polonica. Series A . Forestry

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2022

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tom 64

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nr 2

17

Gender and age structure as well as body weight of partridge (Perdix perdix L.) during periods of high and low population density in the Lublin Upland

72%

Flis M., Panek M.

Annals of Warsaw University of Life Sciences - SGGW. Animal Science

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2017

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tom 56[1]

Gender and age structure as well as body weight of partridge (Perdix perdix L.) during periods of high and low population density in the Lublin Upland. Studies upon structure of gender and age as well as body weight of partridges were carried out in the Lublin Upland in 1988 and 2015, different in relation to the levels of these animals population density. These features were evaluated in 104 individuals culled in early October. Nearly 4-fold decrease in the population density of this species was recorded between the compared periods. Over 80-fold decrease in the hunting acquisition of partridge occurred the same period. A decrease in the share of females in the population after the breeding period was also found, which probably resulted from an increase in this gender mortality during the breeding season. Proportions of the number of juveniles to adult animals (2.4 and 1.7), and to adult males (4.0 and 1.7) in two subsequent study years, i.e. indicators of the young partridges production, did not differ significantly, but it could be mainly due to a small sample in the latter year. The gender structure of juvenile partridges was 0.94 male per female in 1988 and 0.71 male per female in 2015, which did not significantly differ between periods (χ2 = 0.178). Among adult individuals, 1.5 male per female were recorded in 1988, while only males were reported in 2015. Body weight of young partridges decreased between the years of research by 22.5 gram, i.e. 6%, while adult animals by 12.5 gram, which indicates the decrease in bird size, and thus the individual condition, presumably due to limited food resources. Differences in body weight between periods were statistically significant only at young animals. Such situation can cause enhanced mortality of young partridges in autumn and winter, therefore worsen the existing regress in this species population. The results confirmed that the previous assessment of the causes of the decline in partridges population in Poland, showing an increase in losses during the breeding season, as the main demographic mechanism, were valid also for the second decade of the twenty-first century. It follows that improving the environmental conditions during the breeding season, besides reducing the number of predators, should be an essential part of the partridge active protection programs.

18

Age structure and growth rate of Zonitoides nitidus (O. F. Müller, 1774) (Gastropoda: Pulmonata: Gastrodontidae)

72%

Kuznik-Kowalska E.

Folia Malacologica

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2011

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tom 19

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nr 1

Growth rate and age structure of Zonitoides nitidus (O. F. Müller) were studied based on monthly samples from a population in Muszkowice (SW. Poland). The life cycle is probably a three-year cycle: juveniles hatch from June till October, and winter over at a size of 2.0–4.5 whorls. The growth rate is ca. 0.5–1.0 whorl/month.

19

Social-demographic structure of population in the Lomianki Commune

72%

Litynski M.

Polish Ecological Studies

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1992

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tom 18

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nr 3-4

20

Spatial demographic trends and patterns in the Warsaw urban region

72%

Potrykowska A.

Geographia Polonica

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1992

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tom 59

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