Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 10

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  shrub species
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Response of alpine plant community to simulated climate change: two-year results of reciprocal translocation experiment (Tibetan Plateau)

100%
Zhang F.-W., Li Y.-N., Cao G.-M., Wang S.-P., Zhao X.-Q., Du M.-Y., Wang Q.-X.
Polish Journal of Ecology
|
2011
|
tom 59
|
nr 4
The great sensitivity of the response of alpine plant community to climate change makes the identification of these responses important. In 2007, we conducted a reciprocal translocation experiment on 100 × 100 × 40 cm coherent turf and soil along an elevation gradient of 3200–3800 m on the south slope of Qilian Mountains northeast of the Qinghai-Tibetan Plateau. The aim was to understand the warming/cooling effects on the alpine ecosystem where treatments were simulated by donor elevations below/above receptors. Translocated vegetation comprised the Kobresia meadow at 3200 m, deciduous shrub meadow at 3400 m, forbs meadow at 3600 m, and sparse vegetation at 3800 m. The 5 × 5 cm grid method (50 × 50 cm, 100 grids) was used for surveying plant species absolute abundance in translocated quadrats. Results showed that species richness and Shannon-Weaver index of Kobresia meadow increased significantly (P <0.05) when translocated to 3400 m. Shannon-Weaver index of shrub meadow declined, while shrub species abundance responded slightly both to warming and cooling treatments. Both species richness and Shannon-Weaver index of forbs meadow and sparse vegetation were enhanced evidently at 3200 m and 3400 m. Four groups were identified by non-metric multidimensional scaling based on receptor elevation. Responses of the alpine plant community and the function group appeared to be specific to climate magnitude and specific to function type, respectively. Correlation indicated that climatic factors played a much more important role than soil in the response of the alpine plant community. Four vegetation types were sensitive to climate change, while Kobresia meadow behaved flexibly. Global warming would depress sedges but favor legumes and graminoids.
2

Effect of climate and physiography on the distribution of trees and shrubs species in Northwest Mexico

100%
Martinez-Antunez P., Wehenkel C., Hernandez-Diaz J. C., Gonzalez-Elizondo M., Corral-Rivas J. J., Pinedo-Alvarez A.
Polish Journal of Ecology
|
2013
|
tom 61
|
nr 2
In order to understand the environmental variables that may impact more on the distribution of species of trees and shrubs, a correlation analysis applying the Covariation (C) of Gregorius was conducted among 14 variables of climate and physiography, and the number of individuals of 72 species, which were found in 1804 sampling plots (covering about 123,317 km²) of the National Forests and Soils Inventory (INFyS) developed by the National Forest Commission in Mexico (CONAFOR). Among the studied species there are several of the genera Quercus, Pinus and Junniperus, which are mainly distributed in the Sierra Madre Occidental, where they stand out for their abundance. The results show that the density of 88% of the studied species have a significant correlation (P <0.025) with at least five of the 14 variables analyzed. Seven of the variables showed significant correlation (P <0.025) with at least 74% of the studied species: ‘Julian date of last spring frost’ with an average value of covariation (C) equal to 0.71, ‘average duration of the frost-free period’ with average value of C = 0.71’, degree days above 5℃’ with covariation of 0.69, ‘altitude above sea level’ with C = 0.66; ‘mean temperature in the coldest month’, ‘mean temperature in the warmest month’ and ‘mean annual temperature’, with average values of C = 0.65 for each of these last three variables. The ‘geographic orientation of the ground’ was the least correlated with the density of the species, since only 10% of them showed significant correlation with this variable.
3

The impact of climate change on habitat suitability for Artemisia sieberi and Artemisia aucheri (Asteraceae) – a modeling approach

100%
Mousaei Sanjerehei M., Rundel P. W.
Polish Journal of Ecology
|
2017
|
tom 65
|
nr 1
We determined the current potential distribution of Artemisia sieberi and A. aucheri, two important widespread rangeland shrub species in Iran, using bioclimatic variables with and without the addition of elevation (E) to the MaxEnt model. The impact of climate change on the habitat suitability of the Artemisiaspecies was modeled for mid century under the projected climate change of GFDL-ESM2G (RCP2.6) model, a warmer and slightly wetter condition, and CCSM4 (RCP4.5) model, a warmer and drier condition. The results showed that annual precipitation (AP) and temperature annual range (TAR) were the most important drivers of A. aucheri distribution at a regional scale. With the addition of E to the model, we found that E and AP were the most significant factors in determining the habitat suitability of this species. The most significant factors influencing A. sieberi distribution were AP and annual mean temperature (AMT). E was not identified as the important variable influencing A. sieberi distribution when was added to the model in spite of its high correlation to AMT (|r| > 0.8), while AP was the most important, indicating that A. sieberi is less dependent on elevation than A. aucheri. A. aucheri is regarded as a high elevation species (E > 2500 m) which can be distributed in colder and wetter areas as compared to A. sieberi, a mid-elevation species (E < 2500 m). The projected climate change using both models has a much more impact on A. aucheri, potentially driving more losses and fewer gains in climatically suitable habitat of this species as compared to A. sieberi suggesting the adaptation of the later to a wider range of climatic conditions than A. aucheri. The results of the current and future distribution modeling of the Artemisia species is significant in managing susceptible habitats of these species for climate change and for habitat restoration.
4

Selective foraging on tree and shrub species by the European beaver Castor fiber in lowland and highland habitats in Western Poland

100%
Wazna A., Cichocki J., Bojarski J., Gabrys G.
Polish Journal of Ecology
|
2018
|
tom 66
|
nr 3
In this study, generic composition of food and foraging preferences of the European beaver were determined on sites where the beavers were reintroduced after more than 200 years of absence. Research area was located on lowland (Silesian Lowland) and highland habitats (Bystrzyckie Mountains, Wałbrzyskie Mountains) in western Poland. During the study period, 17,418 trees and shrubs growing within the feeding area of the beavers were marked, out of which 4,669 were found to be cut by beavers. The results showed that the foraging preferences of beavers depend on the availability and diversity of the local food sources. In the lowlands beavers preferred the following species of trees and shrubs as their primary food source: Salix cinerea, S. fragilis, S. caprea, Cornus sanguinea and Populus tremula. In the highlands, beavers preferred Corylus avellana, Sorbus aucuparia, and Fagus sylvatica due to the low availability of Salix and Populus species. Moreover, in the highlands, beavers had to cover longer distances to reach the feeding sites and had to cut trees with larger diameter than in the lowlands.
5

Assessment of the effect of small forest plots planted with deciduous tree and shrub species on the Carabidae [Coleoptera]

100%
Korczynski I.
Forestry
|
1999
|
tom 02
6
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Seed dormancy breaking in Crataegus laevigata

80%
Bujarska-Borkowska B.
Dendrobiology
|
2006
|
tom 56
3-11
Laboratory experiments were made to determine the optimum conditions for dormancy breaking in the midland hawthorn (Crataegus laevigata (Poir.) DC. = C. oxyacantha L.). Its small applelike fruits should be collected when they are fully ripe (in Poland in October). The nutlets extracted from the fruits must be dried at room temperature to the moisture content of 9–13%. The dormancy of midland hawthorn seeds can be overcome by: (1) stratification in a moist medium: 20~30°C/3°C, 16–20 weeks at 20~30°C (16+8 hrs or 24+24 hrs) followed by 16–18 weeks at 3°C, i.e. to the time when first radicles start to appear; or (2) chemical scarification in concentrated sulphuric acid for 2 or 3 hrs, followed by warm stratification at 27.5°C or 20~30°C for 4 weeks and cold stratification at 3°C, lasting 19–21 weeks, i.e. to the time when first radicles start to appear. The stratified seeds germinate vigorously (in 3–5 weeks) and at a high percentage at temperatures of 3~15°C or 3~20°C (16+8 hrs) and all seedlings emerge in such conditions about 4–6 weeks after sowing. Seed germination after stratification or scarification can be stopped by partial desiccation of seeds. Seed desiccation after stratification to the moisture content of 10–13% and sealed storage at –3°C for one year do not reduce seed germination and seedling emergence rates of the previously pretreated seeds. Storage for 20 months at –3°C of seeds dried after harvest to the moisture content of 14% does not reduce their germination and seedling emergence.
7

Scaling relationships of leaf traits do not change among months in a temperate shrub species

80%
Du N., Wang R.-Q., Zhang X.-R., Xu F., Tan X.-F., Guo W.-H.
Polish Journal of Ecology
|
2013
|
tom 61
|
nr 1
Leaf traits scaling relationships were compared in different months (May, June, July and August) in a temperate shrub species, Vitex negundo Linn. var. heterophylla (Franch.) Rehd. Leaf traits variation and the impact of environment were also studied. Our results showed that specific leaf area (SLA), leaf nitrogen content (Nmass), leaf phosphorus content (Pmass) and leaf chlorophyll content (Chlmass) were positively correlated, and all of the pairwise relationships showed a common standardized major axis (SMA) slope in different months. The variation of SLA, chlorophyll a content (Chlmass a), chlorophyll b content (Chlmass b), Chlmass a/b and maximum quantum yield of PSII (Fv/Fm) were mainly habitat-dependent, while the variation of Pmass and Nmass/Pmass were mainly month-dependent. Redundancy analysis (RDA) was used to further explore the relationships between leaf traits and environmental factors. We found that plants under shade (the relative photosynthetic photon flux density was about 10%) developed light-capturing behavior at leaf level (higher SLA) and cellular level (higher Chlmass/Nmass and lower Chlmass a/b). The increased Nmass/Pmass with month was mainly resulted from the large absorption of soil nitrogen and the decrease of soil pH. In a word, our study indicates that species may not have fundamentally different carbon capture strategies in different months. Variation of different leaf traits are related to different environmental factors in the field.
8
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Micropropagation of Grewia tenax (Forssk.) Fiori – an important ethnomedicinal plant

80%
Daffalla H. M., Elsheikh A. M., Ali H. A., Khalafalla M. M.
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
|
2019
|
tom 100
|
nr 3
9

Number of sawfly [Hymenoptera, Diprioninae] cocoons damaged by entomophagous animals in selected distances from a plot with different tree and shrub species

80%
Korczynski I.
Forestry
|
2001
|
tom 04
10

Effect of forest plots with different tree and shrub species on the number of Carabidae [Coleoptera] in Scots pine [Pinus sylvestris L.] stands

80%
Korczynski I.
Forestry
|
2001
|
tom 04
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.