Community structure on sandy beaches: patterns of richness and zonation in relation to tide range and latitude
McLachlan, A.; De Ruyck, A.; Hacking, N. (1996). Community structure on sandy beaches: patterns of richness and zonation in relation to tide range and latitude. Rev. Chil. Hist. Nat. 69: 451-467
In: Revista Chilena de Historia Natural. La Universidad de Chile: Santiago. ISSN 0716-078X; e-ISSN 0717-6317, more
|   |
| Keywords |
Aquatic communities > Benthos
Topographic features > Landforms > Coastal landforms > Beaches
Australia [Marine Regions]
Marine/Coastal |
| Author keywords |
Sandy beaches. macrobenthos. community organization. Australia |
| Authors | | Top |
- McLachlan, A.
- De Ruyck, A.
- Hacking, N.
|
|
|
| Abstract |
Recent studies have shown a consistent increase in species richness, abundance and biomass of intertidal macrobenthos over a range of micro/mesotidal sandy beaches from reflective to dissipative conditions. However. beaches occur in a continuum of morphodynamic forms beyond mesotidal dissipative in macrotidal areas: these are ultradissipative beaches and tide flats, where tides take over from waves as the controlling force. This paper tests the hypotheses: 1) that species richness. abundance and biomass continue increasing and 2) that more than three faunal zones may be distinguished on beaches on the above continuum beyond the mesotidal dissipative type. and also examines the hypothesis: 3) that temperate beaches are richer in species than tropical beaches. Two temperate. microtidal. dissipative beaches and four tropical, macrotidal. ultradissipative to tidal flat beaches in Australia were quantitatively surveyed with a total sampling area of 4.5 m² each. The results, when plotted against an index of beach state. indicate that species richness continued to increase over this range of beach types and especially strongly towards the tidal flat. Abundance also increased. but only weakly towards the tidal flat and biomass showed a decreasing trend. The tropical beaches (15-30 species) supported richer faunas than the temperate (12 species) beaches. Similar response to an index of beach state by communities from widely differing regions and latitudes suggests that species richness is probably mainly a function of beach type and latitude may play a minor role. Zonation was indistinct in most cases and no more than three zones could be distinguished on any of the beaches. It appears that in macrotidal regimes, where tides take over from waves as the force controlling beaches. intertidal climate becomes more benign, leading to the presence of species that construct semi-permanent burrows. the attainment of high diversity and thus the development of suitable conditions for biological interactions to play a greater role in community organisation than on microtidal, wave-dominated beaches. |
|
