Browsing by Author "TABILO, EL"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    BODY-SIZE OF CHILEAN FOXES - A NEW PATTERN IN LIGHT OF NEW DATA
    (1995) JIMENEZ, JE; YANEZ, JL; TABILO, EL; JAKSIC, FM
    By using body measurements and weight data of culpeo fox Dusicyon culpaeus Molina, 1782 and chilla fox D. griseus Gray, 1837 from the Chinchilla National Reserve (north-central Chile) and Torres del Paine National Park (southern Chile), the body size distribution of Chilean foxes was analyzed and compared to data previously published by Fuentes and Jaksic (1979). Contrary to those authors, our data show that not only the larger but both species increase in size in southern Chile. Thus, latitudinal size distribution of D. culpaeus and D. griseus may not be the result of character displacement through exploitation competition, as previously interpreted, but of bioenergetic adaptations.
  • No Thumbnail Available
    Item
    HETEROGENEOUS RESPONSES OF SMALL MAMMALS TO AN EL-NINO SOUTHERN-OSCILLATION EVENT IN NORTHCENTRAL SEMIARID CHILE AND THE IMPORTANCE OF ECOLOGICAL SCALE
    (1995) MESERVE, PL; YUNGER, JA; GUTIERREZ, JR; CONTRERAS, LC; MILSTEAD, WB; LANG, BK; CRAMER, KL; HERRERA, S; LAGOS, VO; SILVA, SL; TABILO, EL; TORREALBA, MA; JAKSIC, FM
    A prolonged El Nino Southern Oscillation (ENSO) event during 1991-1992 with three times the normal annual 85-mm rainfall was accompanied by major changes in numbers of small mammals at a semiarid Mediterranean site in northcentral Chile. Several demographic patterns were evident. Akodon olivacerrs, an omnivore, had a rapid increase in population size of more than an order of magnitude. Phyllotis darwini, a granivore-herbivore, showed somewhat delayed, smaller increases superimposed on annual oscillations. Octodon degus, an herbivore, showed a delayed response with larger increases and extended breeding in 1992-1993. Finally, Oligorzyzomys longicaudatus, a granivore, experienced increases during both a dry (1990, ppt = 32 mm) and a wet year (1992). Other species such as Aborthrix longipilis, Abrocoma bennetti, and Thylamys elegans had smaller, delayed demo,oraphic responses. Reproductive rates for the first three species were higher due to the ENSO event only in O. negus males and P. darwini as a quadratic function of time. Survival rates of all four principal species were significantly greater during the 1991-1992 ENSO. Finally, average movement between captures was lower during ENSO years, suggesting behavioral changes. Explanations for these patterns include rainfall-related increases in food-resource levels (A. olivaceus and P. darwini), the importance of source-sink processes in vagile species from more mesic, adjacent habitats (O. longicaudatus), and delayed responses to extrinsic events in species with long gestation (O. degus, A. bennetti). The heterogeneity of species responses suggests different capabilities for small mammals to respond to an extrinsic, large-scale event, and it emphasizes the importance of long-term studies in semiarid systems.