Home – Home – Jornals – Contemporary Problems of Ecology 2009 number 4

Biodiversity patterns of the woodland-steppe ecotone in southeastern Inner Mongolia were investigated. Controlled by climatic factors, the plant species diversity of the woodland-steppe ecotone is medium in comparison to the adjacent woodland zone and steppe zone. From woodland zone, through the woodland-grassland zone and woodland-steppe zone, to the steppe zone, about 2/3 species were replaced at each boundary, only 7 herb species were detected to be distributed in all the four vegetation zones. Landscape classification based on landform, climate and vegetation shows that landform condition is most critical to landscape diversity in the studied area. The most fragmented landform in the woodland zone does not necessarily lead to low plant species diversity. However, similar understory species in different woodland types lead to a continuous woodland vegetation and hence a high species richness. High fragmentation in the woodland-steppe zone and discontinuous distribution of woodlands might be a driving factor for lower species richness in it. Reconstruction of the Holocene climatic changes and vegetation development demonstrates that the highest plant species diversity occurred in the ecotone before 4500 to 2500 ¹⁴C yr B. P. at different sites, while the woodland zone moved much further northwestward. When woodlands retreated from the current ecotone with climatic drying, the fragmentation of woodlands in the current ecotone led to plant species loss.