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A 13-year change in ground-layer vegetation of Carpathian beech forests

Łysik M.

Polish Journal of Ecology

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2009

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Vol. 57, nr 1

47-61

EN

13 year changes in the ground vegetation of natural beech forest were studied in the Babia Góra National Park (South Poland) and compared with the results of similar study in the Ojców National Park published previously (Łysik 2008). In 1-ha permanent research plot homogeneous vegetation patches of the size at least 1m[^2], that differed from neighbouring patches in species composition and/or species share (patch types) were specified and mapped. After intersecting two (for years 1991 and 2004) numerical maps a synthetic map, used then as a basis for evaluating the ground vegetation changes, was created. Changes in each patch and dynamics of each species were derived using adequate formulas. Shannon-Wiener and evenness indices were measured for both years. Comparison of species composition and structure of the herb layer in 1991 and 2004 gives evidence of a highly dynamic nature of the ground layer. On 27% of investigated area vegetation were totally different than 13 years before, while less than 3% of the study area stayed unchanged. On the rest of the area changes of diverse intensity occurred. However, the mean over-plot intensity of changes was about 65% (calculated according to formula 1). Plant cover decreased by about 20%, but at the same time increases were noticed in species number and patch types. There was a significant increase in the area covered by grasses and ferns at the expense of Rubus idaeus L., which used to be a dominant species in 1991. Moreover, cover share of all species become more evenly distributed in comparison with situation 13 years before (evenness index increased from 0.49 to 0.68). The most dynamic species were those associated with decaying stumps and downed logs. These results suggest that, in natural beech forests, overstory dynamics or other mechanisms (like competition with natural recruitment of trees) make the dominance of any species in ground-layer not longer than a decade.

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The slope aspect affects the heterogeneity and growth of ground vegetation in deciduous temperate forest

Chmura D.

Polish Journal of Ecology

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2008

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Vol. 56, nr 3

463-470

EN

The species richness, H' and D' diversity and evenness J in southwestern- and northeastern-facing slopes were compared and height of twelve herbaceous plant species was measured five times during vegetation season in old-growth beech forest. The opposite slopes chosen for studies were similar in relation to slope inclination, type of soil, species composition and canopy cover. Two study plots 60 m[^2] encompassing two rows of 1- by 2-m 15 rectangular quadrates[^2] were established. The study revealed that northern slopes were characterized by significantly lower mean species diversity (H' = 0.82; D' = 0.47) compared to southern slopes (H' = 1.2; D' = 0.59), similar evenness (ca. J = 0.72) and higher heterogeneity with respect to spatial structure using Euclidean distance and range of DCA scores of quadrates of plots. Two-way ANOVA yielded significant differences of effect of slope aspect (P <0.001) and period of time (P <0.01) on average vegetation height. Nevertheless, interaction of time and aspect turned out to be insignificant. The highest mean values of height of plants were observed at the end of July and the end of June. Generally plants growing on north-facing slope were taller and had higher cover than those growing in southern sloped forest. This can be the result of lower species diversity on northeastern slope which favours development of individual species in conditions of weak interspecific competition and stronger intraspecific interactions.

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Ten years of change in ground-layer vegetation of European beech forest in the protected area (Ojców National Park, South Poland)

Łysik M.

Polish Journal of Ecology

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2008

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Vol. 56, nr 1

17-31

EN

Long-term changes in ground-layer vegetation of unique stand of Carpathian beech forest Dentario glandulosae-Fagetum considered partly as a natural succession due to climatic changes and partly as a response to canopy dynamics, were investigated in the Ojców National Park (South Poland). Species composition and structure of the herb layer in the permanent research area were compared in 1993 and after ten years. About 77% of the study area was changed in this period, but the spatial pattern of distribution and intensity was highly mosaic. The mean intensity of changes calculated according to formula (1) derived from changes in percent cover of species was 42%. Herb cover decreased by about 15%, probably due to the rapid development of natural recruitment of trees in the study area (48% of area was covered by dense tree recruitment). In the same time the number of plant species and vegetation types (homogeneous vegetation patches of the size at least 1m2, that differed from neighbouring patches in species composition and/or species share) increased substantially. It is probably due to greater variation of light condition in ground layer created as a result of canopy gaps dynamics (the area of windthrow mounds in the study area increased approximately eight times between 1993 and 2003). There was a significant decline of species typical for beech forests, especially of vernal geophytes like Dentaria glandulosa W.K. and Isopyrum thalictroides L. Although it is too early to predict any directional changes, it is possible that the beech forest community will change into the Tilio-Carpinetum association in some parts of study area. Nowadays the expansion of invasive alien species Impatiens parviflora DC. is the great threat to the forest vegetation of the protected study area and the Ojców National Park. This species in 10 years managed to displace native species in 3% of the study area. The drastic decrease in herbaceous plants cover connected with increase in tree seedlings and saplings, systematic decline of vernal geophytes and typical beechwood species, diversification of ground vegetation structure and composition, and finally occurrence of non-native invasive plant species inform about highly dynamic nature of climax beech forests and generally of temperate forests. Changes are induced probably by both changing climate and overstorey dynamics.