Malo J.E.,Autonomous University of Madrid |
Gonzalez B.A.,University of Chile |
Mata C.,Autonomous University of Madrid |
Vielma A.,University of Chile |
And 3 more authors.
Acta Oecologica | Year: 2016
Feral domestic ungulates may compete with the populations of wild herbivores with which they coexist, particularly so in arid regions. The potential competition between wild camelids and feral donkeys at the eastern sector of the Atacama Desert is evaluated in terms of their coincidence or segregation in habitat use and complemented with a comparison of reproductive output (yearling/adult ratio) of vicuña family groups in the proximity vs. distant from donkey observations. Habitat use of wild camelids and donkeys was sampled driving some 1250 km of roads and tracks at the dry and wet seasons. There were 221 vicuñas (Vicugna vicugna) sightings, 77 for donkeys (Equus asinus), 25 for guanacos (Lama guanicoe) and 8 for hybrids between guanacos and domestic llamas (Lama glama), as well as 174 randomly selected control locations. By means of Generalised Discriminant Analysis and Analysis of Variance we show that all ungulates actively select their habitat, with significant differences between use and availability in the area. Donkeys are relatively abundant in comparison with camelids and coincide broadly with both of them across the altitudinal gradient, but they fall between them in local scale habitat selection and do not seem to force their displacement from their preferred habitats. Thus donkeys occur preferentially on slopes with a high cover of tall shrubs, whereas vicuñas use valley bottoms with grass and guanacos the upper slope zones with grass. The potential for competition between donkeys and wild camelids is thus limited and it does not affect the reproductive output of vicuña in this region. Therefore, with the present knowledge we suggest that population control is not currently merited for feral donkeys. © 2015 Elsevier Masson SAS.
Tobar C.,Santo Tomas University of Chile |
Tobar C.,University of Los Lagos |
Rau J.R.,University of Los Lagos |
Iriarte A.,University of Santiago de Chile |
And 9 more authors.
Ornitologia Neotropical | Year: 2012
In April 2009, at the Salar de Punta Negra (24°35'S, 68°58'W) in the Antofagasta Region of northern Chile, we quantified the composition, diversity, and size of diatoms, the only consumed prey by both adults and nestlings of Andean Flamingos (Phoenicoparrus andinus). We identified a total of 39 species, 34 in the faeces of nestlings and 25 in adult faeces. The most abundant species in both was Surirella sella and Denticula thermalis. The most frequent diatoms observed in the nestlings' faeces were S. sella, D. thermalis, Pinnularia sp. and Haloroundia speciosa, whereas in the adult faeces they were Denticula thermalis, Surirella sella, Pinnularia sp. and Haloroundia speciosa. There was no statistically significant difference in diatoms consumed by adults and nestlings. The dietary similarity between adults and nestlings was 0.644. The nestlings consumed a greater diversity of diatoms than adults. The most consumed diatom by adults (S. sella) was sized between 58 and 140 urn, with a greater frequency for organisms between 70 and 100 um. The size of the diatoms consumed by nestlings was between 40 and 120 um with a greater frequency of organisms between 60 and 90 um. Comparing the sizes of the consumed diatoms, we found that adults preferred individuals of greater size than nestlings. © The Neotropical Ornithological Society.