Browsing by Author "OLIVA, D"

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    ECOLOGICAL CONSEQUENCES OF COSEISMIC UPLIFT ON THE INTERTIDAL KELP BELTS OF LESSONIA-NIGRESCENS IN CENTRAL CHILE
    (1990) CASTILLA, JC; OLIVA, D
    Coseismic uplift from the Chilean earthquake of 3 March 1985 caused changes in the biomass and vertical zonation of rocky intertidal organisms at four sites along 150 km of the central Chilean coast. The 11-60 cm uplift caused widespread mortality mainly of the dominant intertidal kelp Lessonia nigrescens, reducing its biomass in the upper part of its pre-earthquake range and altering the vertical zonation. The L. nigrescens belt shrank from the top by about 0.5-1 m within 1 year of the shocks, then expanded downward by about 1 m. An important part of the primary space liberated at the pre-earthquake upper border of Lessonia was invaded by the barnacles Chthamalus scabrosus and Fehlius cirratus. None of the foregoing changes occurred at two control sites located outside the shock area. The ecological effects of these recurrent sudden and drastic environmental processes on rocky intertidal communities include the liberation of primary space, enhancement of mosaic areas and modification of the vertical zonation of competitively dominant organisms.
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    OTARIA-BYRONIA (DE BLAINVILLE, 1820), THE VALID SCIENTIFIC NAME FOR THE SOUTHERN SEA LION (CARNIVORA, OTARIIDAE)
    (1988) OLIVA, D
    The specific epithets most commonly used for the southern sea lion have been O. jubata, O. leonina, O. flavescens and O. byronia. The latter two are still currently in use. The re-examination of the names that have been applied to the taxon suggests that byronia should have the priority. The epithet flavescens is invalid because the holotype on which the name was based was not a southern sea lion but a neonatal specimen of an arcotocephaline.
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    THE EFFECT OF HUMAN EXCLUSION ON THE POPULATION-STRUCTURE OF KEY-HOLE LIMPETS FISSURELLA-CRASSA AND FISSURELLA-LIMBATA ON THE COAST OF CENTRAL CHILE
    (1986) OLIVA, D; CASTILLA, JC
    We describe the basic ecology of two key-hole limpets, Fissurella crassa and Fissurella limbata, which are heavily harvested by coastal shellfishermen (mariscadores) at the rocky intertidal of central Chile. The ecological role of human predationon these species was assessed. Anthropic exclusion from a stretch of the rocky intertidal at Las Cruces (non-harvested area) for about two and a half years resulted in changes of the densities and size distributions of these fissurelid species as compared to populations in control zones (harvested area). Differential human predation generates, on key-hole limpets, responses of different intensities related to the accessibility of man to the mesohabitats (sheltered platforms, exposed platforms and vertical walls) and fringes of the intertidal (mid-low intertidal and Lessonia nigrescens fringe). Thus, size distributions and mean densities of both fissurelids differ widely between the harvested and non-harvested areas on both platform habitats but not on vertical walls. In the mid-low intertidal fringe, differences are greater than in the less accessible L. nigrescens intertidal fringe. Moreover, we discuss the way in which other species, directly harvested by mariscadores (i.e., the mollusk Concholepas concholepas) can affect the key-hole limpet populations of central Chile rocky shores. Finally, we highlight the ecological role of these limpets on the dynamics of intertidal ecosystems and how they can modify community landscape.