Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: species similarity

Sortuj według:

Ogranicz wyniki do:

Species similarity - distance relationship in wetlands: effect of disturbance intensity

100%

Lu T., Ma K., Zhang Y., Ni H., Fu B.

Polish Journal of Ecology

2009

tom 57

nr 4

647-657

Disturbance is considered to be one of the main factors influencing variations in species diversity. While many experimental and observational studies provide a good understanding of how disturbance maintains the α-diversity, we know little about how disturbance influences β-diversity, and the effects of disturbance intensity on spatial species turnover are lacking. The aim of this paper is to evaluate the effects of disturbance on patterns of species similarity in wetland communities, and to identify how disturbance intensity affects the species similarity - distance relationship. In our study, four isolated wetland remnants under different agricultural drainage ditch densities were surveyed in Sanjiang Plain, Northeast China. Wetland disturbance was assessed by agricultural ditch densities, and species similarity was quantified by the Jaccard index. A simple measure of environmental distance was obtained by using water level and five soil variables, and a corresponding measure of geographical distance was made between pairs of plots from each site. Based on these data, we estimated rates of distance decay through regression of log-transformed compositional similarity against both environmental and geographical distance for pair-wise comparisons of wetland plots from each site. One key finding of our research is that disturbance intensity does influence the species similarity - distance relationship. At each site, species similarity decreased significantly with distance, and both effects of geographical and environmental distance were statistically significant. The results indicate that with disturbance intensity increasing, the distance decay rate decreases.

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

Similarity between seed bank and herb layer in a natural deciduous temperate lowland forest

67%

Wodkiewicz M., Kwiatkowska-Falinska A. J.

Acta Societatis Botanicorum Poloniae

2010

tom 79

nr 2

157-166

Forest seed banks mostly studied in managed forests proved to be small, species poor and not reflecting aboveground species composition. Yet studies conducted in undisturbed communities indicate a different seed bank characteristic. Therefore we aimed at describing soil seed bank in an undisturbed forest in a remnant of European lowland temperate forests, the Białowieża Forest. We compared similarity between the herb layer and seed bank, similarity of seed bank between different patches, and dominance structure of species in the herb layer and in the seed bank of two related oak-hornbeam communities. We report relatively high values of Sorensen species similarity index between herb layer and seed bank of both patches. This suggests higher species similarity of the herb layer and soil seed bank in natural, unmanaged forests represented by both plots than in fragmented communities influenced by man. Although there was a set of core seed bank species present at both plots, yielding high Sorensen species similarity index values, considerable differences between plots in seed bank size and dominance structure of species were found, indicating spatial variability of studied seed bank generated by edaphic conditions. Dominance structure of species in the herb layer was not reflected in the underlying seed bank. This stresses, that natural forest regeneration cannot rely only on the seed bank, although some forest species are capable of forming soil seed banks. While forest seed banks may not reflect vegetation composition of past successional stages, they may inform on history and land use of a specific plot.

Ograniczanie wyników

1 Acta Societatis Botanicorum Poloniae

1 Polish Journal of Ecology

1 Fu B.

1 Kwiatkowska-Falinska A. J.

1 Lu T.

1 Ma K.

1 Ni H.

1 Wodkiewicz M.

1 Zhang Y.

1 2010

1 2009

Wyniki wyszukiwania

Species similarity - distance relationship in wetlands: effect of disturbance intensity

Similarity between seed bank and herb layer in a natural deciduous temperate lowland forest