Diversity and structure of herbaceous plant community in typical water-level-fluctuation zone with different spacing elevations in Three Gorges Reservior

Abstract

Plant community structure characteristics are affected by its habitat. Plant community structure characteristics with different elevations and districts are different because of the unique hydrological condition of the Three Gorges Reservoir( TGR) and geographical condition of different districts. Low( L),Middle( M) and High( H) of typical water-level-fluctuating zone( WLFZ) divided depending on different spacing water level elevations( 145-155 m,155-170 m,170-175 m),were investigated in TGR in order to understand the herbaceous composition,diversity and synusia structure. In the 49 herbaceous species identified,only 4,18and 45 species were present in the L,M and H,respectively. The herb coverage,average density and average height of WLFZ of different water level elevations were( 2. 58% ± 1. 29%)-( 74. 83% ± 2. 57%),( 43. 58 ± 85. 93)-( 466. 08 ± 48. 04) shoots /m2and( 4. 89 ± 0. 56)-( 77. 02 ± 9. 31) cm,respectively. Comprehensive analysis shows that the composition of herbaceous plant species and synusia structure of WLFZ tend to be simple. The species diversity and structure characteristics vary along with water level elevation for different flooding stress and different stages of succession. Our results suggest that the classification of species collocation and optimization of interspecific relationship would be an effective measure for improving herbaceous plants development in the WLFZ.