Browsing by Author "Castilla, AC"

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    Temporal and spatial activity of the key-hole limpet Fissurella crassa (Mollusca: Gastropoda) in the eastern Pacific
    (2001) Serra, G; Chelazzi, G; Castilla, AC
    An automated photographic technique was used to collect quantitative information on the activity patterns of Fissurella crassa under heavy-exposed sea conditions. The activity of this key-hole limpet was confined to nocturnal low tides. Total length of excursions was significantly greater during spring tides than neap tides, as was the maximum distance reached fi,om the refuge. Total duration of excursions and their average speed did not vary significantly according to the spring/neap cycle. While the direction angle of excursions relative to the refuge was not influenced significantly by the spring/neap cycle, the lowest zone within the intertidal was reached by F. crassa during spring low tides only.
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    The bioengineer Perumytilus purpuratus (Mollusca: Bivalvia) in central Chile
    (2006) Prado, L; Castilla, AC
    The mussel Perumytilus purpuratus is distributed from Ecuador to the Strait of Magellan oil the Pacific coast; and also extends along the Atlantic coast up to La Lobcria, Argentina. The species forms dense three-dimensional matrices which constitute a microhabitat for a wide variety of organisms. Here we test the hypothesis that factors determining habitat Structural complexity and environmental heterogeneity of Perumytilus matrices have significant effects oil the associated macrofaunal community. In total we found 92 invertebrate taxa in P. purpuratus matrices. The number of layers (stratification) in the matrix had a significant effect on evenness: the greater the stratification, the lower the evenness index. Sediment retention by matrices in sheltered sectors had a significant effect on evenness: greater sediment retention resulted in lower evenness. Sediment retention also determined significant differences In macrofaunal assemblages. In matrices Without sediment retention, mussel layering and the presence of algae on the shells of P. purpuratus determined significant macrofaunal differences. As a dominant competitor, P. purpuratus plays a major role in intertidal rocky shores where it is present, structuring communities and determining local biodiversity.