Community structure of intertidal boulder-cobble fields in the Straits of Magellan, Chile
Based on quantitative samples taken along 4 transects in mobile hard-bottom intertidal areas of the Canal Whiteside, Magellan region, biotic composition, abundance and distribution patterns are described. The intertidal substrates, mainly formed by boulders and cobbles, represent highly heterogenous...
| Published in: | Scientia Marina |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Consejo Superior de Investigaciones Científicas
1999
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| Subjects: | |
| Online Access: | https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/903 https://doi.org/10.3989/scimar.1999.63s1193 |
| Summary: | Based on quantitative samples taken along 4 transects in mobile hard-bottom intertidal areas of the Canal Whiteside, Magellan region, biotic composition, abundance and distribution patterns are described. The intertidal substrates, mainly formed by boulders and cobbles, represent highly heterogenous habitats from the structural point of view, and demonstrated a species richness higher than previously mentioned in some preliminary reports. Community structure parameters (abundance, species richness, diversity, and evenness) were not homogenous in the study areas, suggesting local dynamics. Differences in the vertical distribution of organisms were also found, suggesting changes of the zonation pattern along the beach profile. The macrofaunal assemblages were dominated by few species, with different specific compositions between transects. In general, representatives of Mollusca (Mytilus chilensis, Perumytilus purpuratus), Polychaeta (Hemipodus simplex), and Amphipoda (Paramoera fissicauda, P. brachyura, Transorchestia chilensis) were the numerically dominant groups. In terms of biomass, molluscs were highly dominant, mainly M. chilensis and P. purpuratus. Among the macroalgae, rhodophytes were the group with the highest presence, but Ulva lactuca (Chlorophyta) was the dominant species. In the upper sandy terrace, no macroorganisms were found. Several species found at Canal Whiteside have a wide circumpolar distribution in Sub-Antarctic regions. A partir de muestras cuantitativas tomadas en cuatro transectos paralelos a la línea de costa, se describe la composición biótica y los patrones de distribución y abundancia de una comunidad intermareal presente en ambientes de fondos duros móviles en el Canal Whiteside, Región de Magallanes. El sustrato intermareal, formado principalmente por bloques y cantos, representa un hábitat altamente heterogéneo y mantiene una riqueza de especies mayor que la mencionada en algunos informes preliminares. Algunos parámetros de la estructura comunitaria (abundancia, riqueza de especies, diversidad y equitabilidad) mostraron diferencias en el área estudiada, sugiriendo dinámicas locales. Se encontraron diferencias en la distribución vertical de los organismos, sugiriendo cambios en el patrón de zonación a lo largo de la playa. La comunidad estuvo dominada por unas pocas especies, aunque la composición específica variara entre transectos. Los grupos numéricamente dominantes fueron Mollusca (Mytilus chilensis, Perumytilus purpuratus), Polychaeta (Hemipodus simples) y Amphipoda (Paramoera fissicauda, P. brachyura, Transorchestia chilensis). En biomasa, los moluscos, principalmente M. chilensis y P. purpuratus fueron altamente dominantes. Entre las macroalgas, el grupo de las Rhodophyta fue el más representativo aunque Ulva lactuca (Chlorophyta) fue la especie dominante. En la parte superior arenosa de la playa no se encontraron macroorganismos. Varias especies encontradas en el Canal Whiteside muestran una amplia distribución en la zona subantártica. |
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