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Latitudinal gradient of species diversity: multi‐scale variability in rocky intertidal sessile assemblages along the Northwestern Pacific coast
Author(s) -
Okuda Takehiro,
Noda Takashi,
Yamamoto Tomoko,
Ito Norihiko,
Nakaoka Masahiro
Publication year - 2004
Publication title -
population ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 59
eISSN - 1438-390X
pISSN - 1438-3896
DOI - 10.1007/s10144-004-0185-9
Subject(s) - species richness , intertidal zone , ecology , latitude , species diversity , rocky shore , beta diversity , biology , alpha diversity , gamma diversity , spatial ecology , intertidal ecology , diversity index , environmental gradient , geography , habitat , geodesy
This study examined the latitudinal gradient of species diversity of rocky intertidal sessile assemblages on the slopes of rocks along the Northwestern Pacific coast of Japan, located between 31°N and 43°N, by explicitly incorporating an hierarchical spatial scale into the monitoring design. The specific questions were to examine: (1) whether there is a latitudinal gradient of regional diversity, (2) how spatial components of the regional diversity (local diversity and turnover diversity) vary with latitude depending on spatial scale, and (3) whether the latitudinal gradient differs between different measures of species diversity, i.e. species richness and Simpson's diversity index. We measured coverage and the presence or absence of all sessile organisms in a total of 150 census plots established at five shores in each of six regions. The results showed that there were clear latitudinal gradients in regional species richness and in species turnover among shores. However, these patterns were not reflected in smaller‐scale local species richness. For Simpson's diversity index, there was no evidence of latitudinal clines either in regional diversity or in spatial components. These results suggest that relative abundance of common species does not vary along latitude, while the number of rare species increases with decreasing latitude.