| Popis: |
As the primary producers in the wetland,one of the most important ecological landscapes with high biodiversity,wetland plants have an important influence on the survival and development of the wetland ecosystem.The plant diversity in the beach wetland was researched extensively in previous studies.However,the diversity of vegetation in the beach wetlands along the Xin′anjiang River in Anhui province was still unclear.For protection and rational utilization of the vegetation in this area,the flora of herbaceous plants in the beach wetlands was analyzed and the species diversity of them was investigated in this paper.The results showed that:(1) The herbaceous plant composition was relatively rich and the total 194 species belonged to 48 families and 131 genera,with Gramineae,Cyperaceae,Compositae and Polygonaceae being dominant families.For all the detective plants,37 families,88 genera,129 species belonged to Dicotyledoneae and 11 families,43 genera,65 species belonged to Monocotyledoneae.The preponderant genera were Polygonum,Cyperu,Euphorbia and Artemisia.The percentage of the genera including only 1 species or 2—5 species was accounted for 97.7%.(2) At family level,the proportion of the cosmopolitan type was bigger than others and reached 43.8%.At genus level,the pantropic type was 30.5% and the cosmopolitan type was 26.0%.The tropic elements were more than the temperate ones(57/40).The floristic geographical components including the tropic,subtropic and temperate characteristics were multiform and the areal-type was various.(3) There were visible changes in the community composite,including the constructive species and dominant species,companion species and their dominance.The dominant species were Cynodon dactylon,Paspalum distichum,Eremochloa ophiuroides,Zoysia japonica,Polygonum hydropiper,Cyperus iria,Leersia japonica,and Alternanthera philoxeroides in the wetlands.Especially Cynodon dactylon and Paspalum distichum were the constructive species and played a very important role in the herb community.However,their important values changed among different sampled plots.Alpha diversity had a similar fashion compared with species richness with the order being upstream midstream downstream.In contrast,β diversity gradually increased with the order being upstream midstream downstream.The specific reasons should deserve deep researches.We put forward some strategies of protection and restoration towards the main problems in biodiversity conservation in the wetlands along the Xin′anjiang River. |
