| The extremely arid desert National Nature Reserve in Anxi is located in the An-Dun basin of the west part of Hexi Corridor in Gansu, is the only multi functional and comprehensive reserve to protect the extremely arid desert biodiversity in China currently.Based on the field investigation, combined with the identification of specimens, data collection and sorting, the article has had the statistical analysis on floristic geography and vegetation types of tracheophytes in reserve. The principal conclusions of this analysis are as follows:On the conclusion of floristic geography of tracheophytes in reserve:1.There are63families,210genera,455species (excluding infraspecies),15wild plant varieties,21cultivated plants of tracheophytes in reserve,including19species and1variety of new records in Gansu,1endemic genera and82endemic species in China.2.There are12dominant families,accounted for19.1%of the total families in reserve. The dominant families including134genera, accounted for63.8%of the total genera and including333species, accounting for73.2%of the total number of species in reserve.So the number of genera and species of the12dominant families is absolute advantage in reserve, which play a leading role in composition of floristic geography in reserve. Tamaricaceae, Zygophyllaceae,Chenopodiaceae,Polygonaceae of them are the dominant families and typical families. Monospecific families and oligospecific family accounted for81.0%of the total number of families and monogeneric families and oligogeneric families accounted for73.1%of the total number of families in reserve.They are a larger part of the composition of families, but containing the less number of species and genera.3.There are10dominant genera,accounted for4.8%of the total gengera, including95species, accounted for20.9%of the total number of species in reserve. The number of monospecific genera and oligospecific genera is162, accounted for77.1%of the total number of species, which including205species, accounted for45.1%of the total number of species in reserve. The monospecific genera and oligospecific genera play a very important role in the composition of floristic geography in reserve no matter the amount of genera and species included.4.Statistics of distribution type of families, genera,and Chinese endemic species:The63families of tracheophytes in reserve can be divided into5positive types and4variants.The210 genera can be divided into13positive types and13variants. Based on the system of the geography distributing type of tracheophytes in reserve which has been established preliminarily this time, the82Chinese endemic species are divided into11types,7subtypes.5.The characteristics of flora:①The north temperate element plays an important role in the composition of floristic geography in reserve,which is a large propotion;②The element of floristic geography in reserve is very similar with the Central Asian desert flora’s. By inference, they originated from the same floristic geography;③The floristic geography in reserve has certain relation with the ancient Mediterranean.Speculated, the flora in reserve may be developed from the dry flora of the ancient Mediterranean coast;④The flora in reserve and Mongolia floristic elements interweave each other;⑤Cosmopolatan(code1),tropical Asia and tropical America disjuncted (code3) and old world tropic (code4) have a great impact on the flora of the area;⑥The types of floristic geography of Chinese endemic species in reserve are the northwest distribution primarily.The types of Alashan plateau and the subtypes of Hexi Corridor are advantage.On the conclusion of vegetation types of tracheophytes in reserve:1. This vegetation investigation confirmed6vegetation type groups,8vegetation types,11vegetation subtypes and44formations. Among them,the desert vegetation type group includs17formations, the meadow vegetation type groups includs14formations, the grassland vegetation type group includs5formations, the shrub vegetation type group includs4formations, the broad-leaved forest vegetation type group and the swamp vegetation type group include2formations respectively.2. This vegetation survey added1vegetation types and19formations in the original basis. |
PDF Full Text Request