Publication details

Plant species richness in continental southern Siberia: effects of pH and climate in the context of the species pool hypothesis.

Authors

CHYTRÝ Milan DANIHELKA Jiří ERMAKOV Nikolai HÁJEK Michal HÁJKOVÁ Petra KOČÍ Martin KUBEŠOVÁ Svatava LUSTYK Pavel OTÝPKOVÁ Zdenka POPOV Denis ROLEČEK Jan ŘEZNÍČKOVÁ Marcela ŠMARDA Petr VALACHOVIČ Milan

Year of publication 2007
Type Article in Periodical
Magazine / Source Global ecology and biogeography
MU Faculty or unit

Faculty of Science

Citation
web http://onlinelibrary.wiley.com/doi/10.1111/j.1466-8238.2007.00320.x/abstract
Field Ecology
Keywords Calcicole/calcifuge; forest-steppe; plant community; Pleistocene environments; precipitation; soil acidity; tundra; vascular plants
Description Aim: Many high-latitude floras contain more calcicole than calcifuge vascular plant species. The species pool hypothesis explains this pattern through an historical abundance of high-pH soils in the Pleistocene and an associated opportunity for the evolutionary accumulation of calcicoles. To obtain insights into the history of calcicole/calcifuge patterns, we studied species richness-pH-climate relationships across a climatic gradient, which included cool and dry landscapes resembling the Pleistocene environments of northern Eurasia. Location: Western Sayan Mountains, southern Siberia. Methods: Vegetation and environmental variables were sampled at steppe, forest and tundra sites varying in climate and soil pH, which ranged from 3.7 to 8.6. Species richness was related to pH and other variables using linear models and regression trees. Results: Species richness is higher in areas with warmer winters and at medium altitudes that are warmer than the mountains and wetter than the lowlands. In treeless vegetation, the species richness-pH relationship is unimodal. In tundra vegetation, which occurs on low-pH soils, richness increases with pH, but it decreases in steppes, which have high-pH soils. In forests, where soils are more acidic than in the open landscape, the species richness-pH relationship is monotonic positive. Most species occur on soils with a pH of 6-7. Main conclusions: Soil pH in continental southern Siberia is strongly negatively correlated with precipitation, and species richness is determined by the opposite effects of these two variables. Species richness increases with pH until the soil is very dry. In dry soils, pH is high but species richness decreases due to drought stress. Thus, the species richness-pH relationship is unimodal in treeless vegetation. Trees do not grow on the driest soils, which results in a positive species richness-pH relationship in forests. If modern species richness resulted mainly from the species pool effects, it would suggest that historically common habitats had moderate precipitation and slightly acidic to neutral soils.
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