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@article{376331, author = {Chytrý, Milan}, article_location = {Uppsala}, article_number = {3}, language = {eng}, issn = {110-9233}, journal = {Journal of Vegetation Science}, title = {Phytosociological data give biased estimates of species richness}, url = {http://www.sci.muni.cz/botany/chytry/JVS2001.pdf}, volume = {12}, year = {2001} }
TY - JOUR ID - 376331 AU - Chytrý, Milan PY - 2001 TI - Phytosociological data give biased estimates of species richness JF - Journal of Vegetation Science VL - 12 IS - 3 SP - 439 EP - 439 PB - Opulus Press SN - 1109233 UR - http://www.sci.muni.cz/botany/chytry/JVS2001.pdf N2 - Large phytosociological datasets of three types of grassland and three types of forest vegetation from the Czech Republic were analysed with a focus on plot size used in phytosociological sampling and on the species-area relationship. The datasets included altogether 12,975 relevés, sampled by different authors in different parts of the country between 1922-1999. It was shown that in the grassland datasets, the relevés sampled before the 1960s tended to have a larger plot size than the relevés made later. No temporal variation in plot sizes used was detected in forest relevés. Species-area curves fitted to the data showed unnatural shapes, with levelling-off or even decrease in plot sizes higher than average. This distortion is explained by the subjective, preferential method of field sampling used in phytosociology. When making relevés in species-poor vegetation, many researchers probably tend to use larger plots in order to obtain species-richer relevés. They seem to do that because a higher number of species gives a higher probability of more diagnostic species being found in the relevé; in the Braun-Blanquet classification system such a relevé can be more easily classified. This behaviour of phytosociologists has at least two consequences: (1) phytosociological databases under-represent species-poor vegetation types or are artificially biased towards higher species richness; (2) the suitability of phytosociological data for species richness estimation is severely limited. ER -
CHYTRÝ, Milan. Phytosociological data give biased estimates of species richness. \textit{Journal of Vegetation Science}. Uppsala: Opulus Press, 2001, roč.~12, č.~3, s.~439-444. ISSN~110-9233.
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