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Wyszukujesz frazę "species structure" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
First data of age, condition, growth rate and diet of invasive Neogobius melanostomus (Pallas, 1814) in the Pomeranian Bay, Poland
Autorzy:
Rybczyk, Agnieszka
Czerniejewski, Przemysław
Keszka, Sławomir
Janowicz, Mariola
Brysiewicz, Adam
Wawrzyniak, Wawrzyniec
Powiązania:
https://bibliotekanauki.pl/articles/1844420.pdf
Data publikacji:
2020
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
diet
fish alien species
Gobidae
growth rate
Pomeranian Bay
population structure
Opis:
Round goby (Neogobius melanostomus (Pallas, 1814)) is an invasive species in the Oder River. In this study, age of 147 fish was determined using scales and otoliths, and the Fraser-Lee back-calculation method was used for population structure and theoretical length growth rates with 3 mathematical models of growth: von Bertalanffy, Ford–Walford and 2nd degree polynomial. Fish condition was determined using Fulton, Le Cren and Clark equations. Average total length and weight of fish was 162.00 mm and 83.00 g, respectively. Males were more abundant than females, representing 70% of the fish caught, and achieved greater total lengths and weights. Age 2+ dominated females and 3+ males age groups. Of the three mathematical models used to estimate fish growth, the 2nd degree polynomial model had the best fit to back-calculated lengths. Males had slightly higher growth rates than females in the first two years of life but comparable in subsequent years. The diet consisted of various benthic organisms that varied with fish age. The most frequently occurring food component was Dreissena polymorpha, which accounted for approximately 70% in the diet of fish with a body length greater than 191 mm.
Źródło:
Journal of Water and Land Development; 2020, 47; 142-149
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temporal variation in species composition, diversity and regeneration status along altitudinal gradient and slope: The case of Chilimo dry Afromontane forest in the Central Highlands of Ethiopia
Autorzy:
Tesfaye, Mehari A.
Gardi, Oliver
Blaser, Jűrgen
Powiązania:
https://bibliotekanauki.pl/articles/1046543.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Abundance
Ethiopia
altitude gradient
native species
population structure
saplings
seedlings and shrubs
Opis:
This study is aimed towards investigating the temporal variation in species composition, diversity and regeneration status of Chilimo dry Afromontane forest in the Central Highlands of Ethiopia. A total of 35 permanent sample plots of 20 m × 20 m (400 m2) each were established in the natural forest, laid out on transects of altitudinal gradients, with a distance of 100m between plots. The plots were measured twice in 2012 and 2017. Three subplots, 5m × 5m, and 1 m2 were laid out inside the main plots for sapling, shrub and seedling data collection. Species composition, diversity, important value index (IVI) and regeneration data were analyzed using appropriate formulas. Data analysis was made using R - studio software. A total of 31 trees and shrubs representing 25 families were recorded, 20 (64.52 %) were trees and 11 (35.48 %) were shrubs. Thereof, 28, 23 and 26 species under highest, middle and lowest altitudinal gradient were recorded. The most dominant tree species were: Juniperus procera, Podocarpus falcatus, Olea europea, Scolopia theifolia and Allophyllus abyssinicus. The species composition, diversity, abundance, dominance and important value index significantly varied among species, altitudinal gradient and slope. The diameter distribution was an inverted J - shaped distribution pattern. The highest species richness and diversity index were found under middle altitudinal gradient, while the lowest species richness and diversity index were found under the highest altitudinal gradient. The mean annual volume increment ranged from 4.223 to 0.228 m3 ha-1 yr-1, while the basal area increment varied from 0.85 to 0.020 m2 ha-1 yr-1. Among the sampled species, ten species had fair, 5 poor and 14 species had no regeneration. In conclusion, the Chilimo dry Afromontane forest is suffering from low recruitment and regeneration. Thus, appropriate forest management options should be implemented.
Źródło:
World Scientific News; 2019, 138, 2; 192-224
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Body size, condition, growth rate and parasite fauna of the invasive Perccottus glenii (Actinopterygii: Odontobutidae) from small watercourse in the Vistula River basin, Poland
Autorzy:
Czerniejewski, Przemysław
Linowska, Angelika
Brysiewicz, Adam
Kasowska, Natalia
Powiązania:
https://bibliotekanauki.pl/articles/293036.pdf
Data publikacji:
2020
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
age and growth
Amur sleeper
Habdziński Canal
invasive species
parasites
population structure
Opis:
For the last few decades there have been reports not only of the occurrence of new invasive species of European watercourses, but also their increasing expansion. One of such species is the Amur sleeper (Perccottus glenii). The present work contains assessment of age and length distribution, condition as well as growth rate and analysis of the parasite fauna of the Amur sleeper from the waters of the Vistula River tributary in its middle course (the Habdziński Canal). During the catch performed in 2017 and 2019, the total of 177 Amur sleepers were recorded in the studied watercourse and a statistically significant sex structure disproportion was observed. Among the specimens caught in 2017 dominant were fishes with lengths of 50.1–60.1 mm whereas in 2019 the majority of the Amur sleeper specimens measured 30.1–50.0 mm. Six age groups were recorded among the caught fish with a clear prevalence of specimens aged 1+ (70.06%). The most frequently recorded parasite of P. glenii was non-quantifiable Trichodina rostrata ciliate for which the Amur sleeper from the Polish waters appeared to be a new host. Moreover, the presence of an acanthocephalan Acanthocephalus lucii, not recorded in Poland in this host before, was observed in the chyme. Also, accidental presence of larvae of the Opisthioglyphe ranae tremadote, which is a parasite typical of amphibians, was also recorded. Despite unfavourable habitat conditions and increased volumes of biogenic substances in the waters of the Habdziński Canal, the Amur sleeper found convenient conditions to reside in this small watercourse.
Źródło:
Journal of Water and Land Development; 2020, 44; 33-42
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cochlearia polonica Frohl. (Brassicaceae), a narrow endemic species of southern Poland: history of conservation efforts, overview of current population resources and genetic structure of populations
Autorzy:
Cieslak, E.
Kazmierczakowa, R.
Ronikier, M.
Powiązania:
https://bibliotekanauki.pl/articles/56510.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
Cochlearia polonica
Brassicaceae
endemic species
Southern Poland
history
conservation effort
current population
population resource
genetic structure
genetic variation
population structure
Opis:
Cochlearia polonica Fröhl. (Brassicaceae) is one of the rarest species in the Polish and European flora and a taxon endemic to a very small area in southern Poland. Due to industrial activities and subsequent transformation of habitats it was extinct in all natural localities around 1994. The persistence of the species was ensured thanks to the active protection efforts including a series of transplantations based on the material from the last and decreasing natural population. The history of conservation efforts of C. polonica provides a model example of successful active protection in the European flora. Here, we provide a complete review comprising the following aims: (i) outline of the discovery and taxonomic conceptions on C. polonica, (ii) review of conservation efforts aimed at preserving its populations, (iii) description of the existing population resources, and (iv) analysis of the genetic structure of all existing populations based on previously published data and new, supplementary results.
Źródło:
Acta Societatis Botanicorum Poloniae; 2010, 79, 3
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stand structure and natural regeneration of Taxus baccata at "Stiwollgraben" in Austria
Autorzy:
Dhar, A
Ruprecht, H.
Klumpp, R.
Vacik, H.
Powiązania:
https://bibliotekanauki.pl/articles/41025.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
English yew
Taxus baccata
yew
tree species
Austria
gene conservation
natural regeneration forest
stand structure
population structure
vitality
yew decline
Opis:
English yew (Taxus baccata L.) is a rare tree species in Austria and gene conservation forests reserves are used to maintain English yew populations by silvicultural treatments. This paper describes the current situation of an English yew population at “Stiwollgraben”in Austria with regard to stand structure, vitality and natural regeneration. The area is one of the most important sites in Austria as it consists of 2236 yews.The vitality condition of the yew is very good, and more than 79% of the yews have been assessed as very vital to vital. The potentiality for natural regeneration (13019 one-year seedlings ha–1) is very high, but not all height classes are represented. This indicates a high survival ability of English yew at this site. Three different treatment strategies are described to maintain the yew population. The future effects of these treatments are discussed in the light of the environmental requirements of English yew.
Źródło:
Dendrobiology; 2006, 56; 19-26
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Population structure, morphometry and individual condition of the non-native crab Rhithropanopeus harrisii (Gould, 1841), a recent coloniser of the Gulf of Gdansk (Southern Baltic Sea)
Autorzy:
Hegele-Drywa, J.
Normant, M.
Szwarc, B.
Podluska, A.
Powiązania:
https://bibliotekanauki.pl/articles/49100.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Harris mud crab
Rhithropanopeus harrisii
non-native species
Gdansk Gulf
Southern Baltic Sea
population structure
morphometry
condition factor
biological invasion
Źródło:
Oceanologia; 2014, 56, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The population structure and regeneration of Sorbus torminalis in Hadecka planinka National Nature Reserve (Czech Republic)
Autorzy:
Madera, P.
Kohoutek, M.
Senfeldr, M.
Repka, R.
Powiązania:
https://bibliotekanauki.pl/articles/41463.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
population structure
regeneration
Sorbus torminalis
wild service tree
age structure
forest system
species protection
chequer tree zob.wild service tree
checker tree zob.wild service tree
Hadecka Planinka National Nature Reserve
Czech Republic
Opis:
We performed a detailed overall field survey of all specimens of the wild service tree Sorbus torminalis (L.) Crantz in the research area in the Hádecká planinka National Nature Reserve. This research area, with an area of 80 ha, contains one of the largest populations of the tree in Europe. In all, 1713 specimens were found. This study provides a detailed description of the wild service tree population in the area. The basic biometric parameters (height, GBH, social position, fertility) of thepopulation were assessed. The main emphasis of our analysis was to evaluate the population's age structure. We used estimates of age structure based on the Chapman-Richards growth function to perform this evaluation. During the past twenty years, the natural regeneration of the wild service tree in the nature reserve has decreased considerably. At an experimental plot where a high forest was converted to a coppice with standards, regeneration occurred over 75% of the area. Root suckers were found at the beginning of the observation period. After 2–3 years, generative regeneration occurred.
Źródło:
Dendrobiology; 2012, 68
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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