Wyniki wyszukiwania - Biblioteka Nauki

1

Dynamics of changes in the structure of the forest edge in Slovakia

100%

Škodová M. , Gajdoš A.

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tom 1

22-29

PL

Forest edges generally represent a very important element of ecological stability. The goal of this paper is to classify the types of anthropogenic forest edges in the area of Starohorské Mountains and to analyze anthropogenic impacts on the selected attributes of forest edges. We evaluated the attributes of a biocomplex, type of forest edge, its structure, consistence, species composition and other factors. The differences in environment variables and anthropic impact were influenced by singularities in the composition and species variability of vegetation. In the monitored areas we defined seven types and four subtypes of forest edges according to its vertical and horizontal structure. With the help of detrended correspondence analysis (DCA) we also interpreted organization relevés and species by gradients of environment variables, and with the help of canonical correspondence analysis (CCA) we tested their statistical significance. From the results of our research, there is a clear tendency for high diversity of living species in the forest edge. Environmental variables interpreting the highest volume of species variability are the altitude and transect position.

2

Dynamics of changes in the structure of the forest edge in Slovakia

89%

škodová M. , Gajdoš A.

Annales Universitatis Paedagogicae Cracoviensis Studia Geographica

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2010

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tom 1 Dynamika zmian środowiska geograficznego pod wpływem antropopresji

22-29

EN

Forest edges generally represent a very important element of ecological stability. The goal of this paper is to classify the types of anthropogenic forest edges in the area of Starohorské Mountains and to analyze anthropogenic impacts on the selected attributes of forest edges. We evaluated the attributes of a biocomplex, type of forest edge, its structure, consistence, species composition and other factors. The differences in environment variables and anthropic impact were influenced by singularities in the composition and species variability of vegetation. In the monitored areas we defined seven types and four subtypes of forest edges according to its vertical and horizontal structure. With the help of detrended correspondence analysis (DCA) we also interpreted organization relevés and species by gradients of environment variables, and with the help of canonical correspondence analysis (CCA) we tested their statistical significance. From the results of our research, there is a clear tendency for high diversity of living species in the forest edge. Environmental variables interpreting the highest volume of species variability are the altitude and transect position.

3

Structural Diversity Closely Associated with Canopy Species Diversity and Stand Age in Species-Poor Montane Forests on Loess Plateau of China

71%

Liu N. , Wang H. , Nan H.

Polish Journal of Ecology

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2017

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tom Vol. 65, nr 2

183--193

EN

High species diversity is often accompanied with and supported by a diversified stand structure in species-rich natural forests. However, the relationship between species diversity and stand structural diversity is less examined in species-poor forests. In montane forests on Loess Plateau of north-central China in a semi-arid climate zone, canopy species diversity and vertical structure of 57 broadleaves, conifer and mixed stands, with varying stand ages and site conditions, were randomly sampled. Canopy species diversity was represented by Shannon's index (H'). Stand structural diversity was represented by two indices respectively, i.e. coefficients of variation of diameter measurements at breast height (CVdbh) and Shannon's index of diameter classes (H'dbh). Structural equation models (SEMs) were constructed to explore multiple relationships between stand structural diversity and canopy species diversity, stand age and elevation. Both stand structural diversity indices increased directly with H' and stand age. However, indirect positive effect of stand age via increasing H' was only significant on CV. H'dbh provided positive feedback on H', while effect of stand age was only indirect via increasing structural diversity. Elevation significantly affected coefficients of variation of diameter, which was probably a sampling effect due to narrow distribution of broadleaves-conifer stands in altitudinal range. In conclusion, the results showed that stand structural diversity and canopy species diversity and stand age are closely associated with the species-poor montane forests like these on Loess Plateau of north-central China.

4

The Effect of Fallow Period Length on the Abundance and Diversity of Usable Plant Assemblages in Shifting Cultivation System (Swidden Agriculture) in Northern Laos

62%

Delang C. O. , Weiyi X. , Brooke B. , Chun K. P.

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tom Vol. 64, nr 3

350--356

EN

Shifting cultivation, or swiddening, involves alternating cycles of cropping and fallow periods. Rather than being abandoned, the fallow swidden fields provide a source of important plant products for remote, forest-dwelling human communities. In northern Laos, the traditional length of fallow periods used to range between five and 11 years, depending on the availability of land and quality of the soil. Fallow periods are currently being shortened because of population pressures and government policies. To determine the potential impacts of shorter fallow periods, 128 swidden fallows of various ages (up to 20 years), located at altitudes between 400 and 800 m a.s.l. in northern Laos were sampled for usable plants. The impact of fallow length on plant abundance and species diversity was analysed. The number of usable plant species was found to increase with the fallow age until it was 11–12 years old, and then decline, while the abundance of usable plants increased beyond that period. We conclude that shorter fallows will result in a significantly smaller usable plant abundance and species diversity for the villagers. We propose that 11–12-year-long fallows should be considered in order to fully exploit the greater plant volume of older fallows as well as the compositional shift of species in fallows over time.