Abstract ID
eflows24
Type
Oral
Theme
eflows
Full title
The interaction between vegetation zones and environment factors in the tidal marsh of the Yangtze Estuary
Abstract text
The vegetation zonation across transects of environmental gradients has been of great interest to ecologists.
Distinct boundaries between different communities often occur under natural conditions. Among large group of
environmental factors that determine vegetation establishment, which factor contributes the most at the edge? Is
this factor also a determinant at other edges? Answers to these questions will help to understand the vegetation
succession mechanisms in habitats with obvious environmental gradients such as tidal marshes.The East
headland of Chongming Island at the Yangtze (Changjiang) Estuary provides an ideal experimental site to
delineate the key factors that controls vegetation zonation under natural conditon. Twenty-two transects were
established across dominant vegetation zones such as <i>Phragmites australis, Scirpus mariqueter, Spartina
alterniflora</i>, as well as mudflat. Factors such as micro-elevation, soil salinity, soil moisture, soil temperature,
soil compactness, pH, redox potential, and ground water depth, were measured during 2007-2008. Statistical
methods of Multivariate ANOVA (MANOVA), Pearson correlation and Principal Component
Analysis（PCA）were employed to analyze the data. The results showed that soil salinity, soil water
content, and shallow groundwater determined the vegetation zones structure at micro-scale, while elevation has
little effect. At meso-scale, all environment factors between different vegetation zones showed significant
differences. Elevation, soil salinity, soil water content and shallow groundwater together determined the
dynamics of vegetation spatial distribution. The elevation, especially, determined the dynamics, development
and evolution of mudflat through its influences on microtopography, and consequently constrained the dispersal
and establishment of pioneer species. The species’ responses to environment were certainly also one of the
main reasons of vegetation zonation, such as the differences in soil compactness and temperature among
different vegetation zones, which affected the distance of vegetation dispersal. Further studies will be carried out
to compare these results with other vegetation zones in the Yangtze estuary.
Submission date
2009-10-22
Keywords
vegetation zonation; distribution; environmental factors; saltmarsh pineer zone; Yangtze estuary
Will be submitting paper?
Yes