Sclerophyllous evergreen broad-leaved forest in Yunnan — A remnant vegetation related to Tethys

Abstract

Widely occurred on diverse habitats from hot dry deep valleys to cold temperate mountains, the sclerophyllous evergreen broad-leaved forest dominated by Quercus species (Fagaceae), is an unique vegetation type in Yunnan. The forest is similar to sclerophyllous oak forests in the modern Mediterranean regions on physiognomy. It differs obviously from the other subtropical evergreen broad-leaved forests in Yunnan by its particular physiognomy, structure, characteristic tree species and geographical distribution, and is named as “sclerophyllous evergreen broad-leaved forest” in the vegetation classification of Yunnan. The sclerophyllous forest is a special vegetation type developed to adapt to the new environment during uplift of the Himalayas. The dominant tree species of the forest show Mediterranean floristic affinity, but they presently distribute mostly in southwestern China. Except for Quercus species, its floristic composition is the same as other neighbor vegetations. The community structure of sclerophyllous evergreen broad-leaved forest is simple. The typical forest community has a profile of tree-shrub-herb layers as common forests, but hemicryptophyte plants absolutely dominate in the communities on cold temperate mountains, and herbaceous plants dominate in the communities at hot dry valleys in its life form. The sclerophyllous oak species fossils recorded in moist tropical-subtropical evergreen broad-leaved forest in Tethys region before Miocene. Until Pliocene epoch, the modern Mediterranean climate formed and drought-resistant Mediterranean flora arose, the sclerophyllous evergreen broad-leaved forest evolved from the former tropical-subtropical evergreen broad-leaved forest with the Himalayas uplift.

Keywords

• sclerophyllous evergreen broad-leaved forest
• ecological characteristics
• species composition
• geographical distribution
• origin and evolution