Browsing by Author "ARMESTO, JJ"

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    DISCOVERY OF A CONTINENTAL POPULATION OF THE RARE DARWIN FOX, DUSICYON-FULVIPES (MARTIN, 1837) IN CHILE
    (1990) MEDEL, RG; JIMENEZ, JE; JAKSIC, FM; YANEZ, JL; ARMESTO, JJ
    The rare Darwin''s fox Dusicyon Fulvipes (Martin, 1837) was thought to be restricted to Chiloe Island in southern Chile, and to be a subspecies of Dusicyon griseus. We report the findings of a continential population of D. fulvipes, 600 km north of its known insular ranges and in sympatry with D. griseus. We document for the first time the food habits of Darwin''s fox, add new information on its morphometry, and discuss the systematic, zoogeographic and ecological implications of the discovery of the continental population.
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    RELATIONS BETWEEN VEGETATION STRUCTURE AND SLOPE ASPECT IN THE MEDITERRANEAN REGION OF CHILE
    (1978) ARMESTO, JJ; MARTINEZ, JA
    The vegetation structure on 4 slopes of different aspect (north, west, east and south) in the mediterranean zone of Chile was analyzed. The evergreen and summer-deciduous life-forms are predominant. The south-, east- and west-facing slopes are closely similar in terms of floristic composition, and on these slopes the numbers of species of evergreens and the plant dimensions are greater than on the north-facing slope. Only the latter shows a high cover of summer-deciduous species. The 4 slopes may fall on a non-linear moisture gradient, with the north-facing slope at the xeric end. A certain number of hygrophilous species restricted to the south-facing slope are interpreted as relicts of the southern rain forest expansion which occurred during the Pleistocene. The vegetation of the west- and east-facing slopes is most similar to the Chilean matorral. The north-facing slope contains a component of xeromorphic species which may have invaded from the north. Intensive wood-cutting and/or cattle-grazing of evergreen species in central Chile may have contributed to the high cover of xeromorphic plants.
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    TREE SPECIES REGENERATION IN A MID-ELEVATION, TEMPERATE RAIN-FOREST IN ISLA-DE-CHILOE, CHILE
    (1988) ARMESTO, JJ; FUENTES, ER
    The regeneration of canopy and subcanopy species in a mid-elevation, primary rain forest in the Coastal Range of Isla de Chiloe (42.degree.30''S), in the cold-temperature region of Chile, was studied by comparing seedling and sapling abundances under the forest canopy, and within 36 tree-fall gaps. The forest was dominated by Amomyrtus luma and Laurelia philippiana (33 and 32% of the main canopy individuals), and two subcanopy species (Myrceugenia ovata, and Myrceugenia planipes) were also important. Uncommon species in the canopy were Drimys winteri, Amomyrtus meli, and Raphithamnus spinosus. Tree-fall gaps were created generally by the fall of several trees, and the main canopy species were the principal gap-makers. Gap sizes varied between 28 and 972 m2, with a mean of 197 m2. Seedling and sapling abundances indicate that the dominant species are capable of regenerating below the canopy, but they also germinate and show enhanced growth within small light gaps. For one of the common subcanopy species (M. planipes) and the two infrequent canopy species (D. winteri, and A. meli) regeneration seems to depend entirely on tree-fall gaps. Thus, in this forest, light gaps allow the persistence of infrequent canopy species, but seem less important for the regeneration and maintenance of dominant canopy species.