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Title: Zonation patterns on rocky shores
Author: Wei, Lin
ISNI:       0000 0004 2749 6499
Awarding Body: University of York
Current Institution: University of York
Date of Award: 2011
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Zonation, defined as biological distribution pattern along the vertical dimension, is the most obvious biological phenomenon in the intertidal zone throughout the shore globally. The formation of zonation involves many abiotic and biotic factors and underlying processes. Some early zonation schemes assumed that zonation patterns are merely controlled by tidal level, specifically" critical tidal levels". Later, based on observations of shores in different regions of the world, ecologists increasingly believed that "biological zones" would be more appropriate for describing zonation in the intertidal zone and this approach is accepted by most ecologists currently. But because of a lack of quantitative descriptions and criteria, "biological zones" cannot be assessed or described accurately for a practical guideline to be used in fieldwork around the world. Under the framework of hierarchical theory, different scales of sampling were conducted for revealing the zonation patterns by multivariate analysis techniques, including MDS, DCA and cluster analysis, based on a data set derived from a gentle sloping gravel flat in Daya bay, in South China. The results show that perception and interpretation of zonation is scale- dependent. A sampling grain (size of sample unit) along the vertical level which is greater than 10cm appears adequate to identify zonation on this shore. Based on these results, zones were grouped under different scale schemes with the best groupings being those at the scale which has the largest discrepancy between zones and the smallest discrepancy within zones. The spatial patterns of abiotic and biotic variables were revealed using classic statistical methods (standardized Moristia Index) and spatial analysis techniques (Mantel correlation). Most dominant species were found to be significantly patchy, as were the environmental factors (sediment, shore height, etc.) measured. However, environmental factors displayed significant correlations with community structure, while most of the dominant species were significant related to community structure, except for vertical height which showed a significant correlation with community structure for most sample lags and for all sampling periods. In order to evaluate the relative contribution of different factors and underlying processes to zonation, the Mantel coefficients between community structure and vertical height, biological factors and spatial autocorrelation were subjected to path analysis and partial path analysis models using a variance partitioning approach. Three basic components were found to be significantly correlated with community structure, represented by spatial, vertical height and biological matrices. Variation in community structure determined by vertical height (Z) is equivalent to "critical tidal level", variation in community structure determined by interactions between biological factors and vertical height (ZB) is equivalent to "biological zone". The value of Z and the value of ZB, zonation scheme of "biological zone" is stronger than that of "critical tidal level". The large value of SZ, variation of community structure determined by the interaction between spatial autocorrelation and vertical height, indicated that zonation cannot solely interpreted in terms of "biological zones" and that the underlying mechanisms of zonation need to be explored further.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available