Can plant community ordinations be affected by various sample plot sizes in grasslands?
Authors | |
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Year of publication | 2005 |
Type | Article in Proceedings |
Conference | 17th International Botanical Congress, Vienna, Austria, 17.-23.7.2005 |
MU Faculty or unit | |
Citation | |
Field | Botany |
Keywords | plot size; phytosociology; PCA DCA; Procrustes analysis |
Description | Vegetation samples from plots that are stored in phytosociological databases often differ by one or two orders of magnitude in size, even within a single vegetation type. This fact may influence vegetation analysis, but the extent of this possible influence has not been investigated so far. The effect of sample plot size on ordination results was investigated in grassland vegetation in southern Moravia (Czech Republic), using data from nested plots of 1, 4, 16, 25 and 49 m2, placed along two ecological gradients: long gradient (including different vegetation types and various climatic condition in a larger area) and short gradient (small area with a floristically homogeneous vegetation type). In both gradients the smallest plot sizes showed the most deviating patterns in ordinations, while samples of larger sizes gave similar results. The transformation of percentage cover also affected the results, more so when samples were collected along short ecological gradient. Samples differing in size by one order (1 and 49 m2) seem to be inappropriate to combine together in ordination analysis, especially when they were sampled along a short ecological gradient. |
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