Browsing by Author "CANCINO, J"

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    COMPARATIVE ECOLOGY OF LESSONIA-NIGRESCENS AND DURVILLAEA-ANTARCTICA (PHAEOPHYTA) IN CENTRAL CHILE
    (1980) SANTELICES, B; CASTILLA, JC; CANCINO, J; SCHMIEDE, P
    The L. nigrescens-D. antarctica belt is the most conspicuous feature of the intertidal-subtidal boundary in central Chile, with L. nigrescens attaining larger cover and biomass values than D. antarctica. Human predation of the otherwise competitively dominant D. antarctica has been suggested as accounting for its scarcity. Testing of this hypothesis included field studies of species distribution in places with and without human accessibility and various degrees of wave impact, comparative morphometric and population studies, evaluation of the ecologic role of the limpet-kelp association and comparative measurements of growth, reproduction and survival capacity. Results indicate that L. nigrescens and D. antarctica have morphologies typically adapted to habitats with different wave shock. Contrary to previous predictions, L. nigrescens appears as a plant better adapted for places with strong wave impact, which are the most common in central Chile. Complete space monopolization by L. nigrescens is prevented by a series of adaptations of D. antarctica. Certain morphological forms of this species are less affected by wave action, allowing a population stock to persist even at the most exposed places. Boring into algal holdfasts by invertebrates weakens the mechanical resistance of old, eroded plants providing open space where juveniles of either species could settle. D. antarctica seems to take greater advantage of this primary space by a fugitive life history. Finally, the survival of D. antarctica increases if attached to the top of L. nigrescens holdfasts. The result of the interaction between these 2 brown algae depends on the degree of water impact. In sheltered habitats competitive displacement of L. nigrescens could occur but it is unlikely to be a continuous process. In exposed habitats D. antarctica is constantly removed by water movement, but persists because of a higher colonization rate.
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    PERTURBATION AND RECOVERY PATTERNS OF STARFISH-DOMINATED INTERTIDAL ASSEMBLAGES IN CHILE, NEW-ZEALAND, AND WASHINGTON STATE
    (1985) PAINE, RT; CASTILLO, JC; CANCINO, J
    When starfish are removed from small portions (< 63-m2 areas) of certain marine communities, mussels increase the percentage of space that they occupy. When compared to other studies in New Zealand and Wasington State new results from Chile indicate that none of these assemblages is stable when perturbed in this fashion. All attain a different state within relatively brief periods. When starfish were permitted to return, 2 different recovery patterns were observed. In Chile, the experimental site converged rapidly toward the undisturbed control; at the other sites, mussels too large to be eaten by starfish continued to dominate the space. The results indicate the importance of size escapes from predation for marine communities. Whether these persistent, but diminishing in spatial converage, stands of mussels are alternative stable states or not is dependent on the definition of stability employed.
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    ROCK-GROUND PATCHINESS IN A SIMPLE LIOLAEMUS LIZARD COMMUNITY (REPTILIA, LACERTILIA, IGUANIDAE)
    (1979) FUENTES, ER; CANCINO, J
    Lizard communities in Chile and California [USA] exhibit rock vs. ground microhabitat partitioning. Two hypotheses explaining this phenomenon, zonation due to differences in food requirements by the species and zonation due to different needs for hiding places from predators, are investigated. Observations and collections of 2 spp. of Liolaemus [L. nigromaculatus and L. platei] (Iguanidae) lizards in a simple habitat suggest the 2 lizard species do not differ significantly in their food preferences and morphological and behavioral differences between species can be related to different predation risks. The species using rocks, presumably the more protected area, tends to be larger, more color and size dimorphic than the species foraging preferentially on the open ground. A natural experiment of decreased effective bird predation risk, further suggests predation is a likely factor in the explanation of rock-ground zonation in these lizards. The roles of interspecific competition and lizard predation are discussed in relation with the Liolaemus community investigated.
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    SPAWNING BEHAVIOR AND EGG CAPSULES OF CONCHOLEPASCONCHOLEPAS (MOLLUSCA - GASTROPODA - MURICIDAE)
    (1976) CASTILLA, JC; CANCINO, J
    Observations on the spawning behavior of the commercially important muricid snail C. concholepas are reported. The sequence of events relating to external transportation, molding and hardening, and attachment of the egg capsules to a substratum were timed and divided into 6 major events. The snails studied in the laboratory spawned between April-Sept. These results and data from the literature reveal an all-year-round spawning activity for the species. The frequency, size and time of spawning were studied over 1 yr. Spawning activity always began at night, suggesting that the species retained its spawning rhythm in the laboratory. There was a direct relationship between snail length and size of capsules spawned. No nutritive eggs were found; the number per capsule varied between 668-14,250 according to capsule size. Hatching time varied between 69-128 days at 13.5-14.5.degree. C.