Time filter

Source Type

San Carlos de Bariloche, Argentina

Lencinas M.V.,CONICET | Martinez Pastur G.,CONICET | Gallo E.,Administracion de Parques Nacionales | Cellini J.M.,National University of La Plata
Journal of Insect Conservation | Year: 2014

Variable retention is an alternative silvicultural approach to timber forest management, which consist in a regeneration treatment with different degrees and patterns of stand retention. It has been proposed to mitigate harmful effects of harvesting, but effectiveness in insect conservation remains unknown in southern Patagonian Nothofagus pumilio forests. Here, the objectives were to: (1) define a baseline of insect diversity in old-growth forests along a site quality gradient (high, medium and low, associated to the forest productivity of each site); (2) evaluate stands with different retention treatments [aggregated (AR) surrounded by dispersed (DR) retention, and aggregated retention surrounded by clear-cut (CC)] and to compare with old-growth unmanaged forests (OGF); and (3) assess temporal changes during the first 4 years after harvesting (YAH). In a long term forest research plot, mobile epigean insect richness and relative abundance were characterized and classified in seven response type groups, using a wide spectrum sampling set. Data analyses included parametric and permutational ANOVAs, multivariate classification and ordinations. There were found 79 species before harvesting, and that richness was not related to site quality. After harvesting, 84 new species were added considering all treatments along the first four sampled YAH, of which 65 % were added to OGF, while in harvested sites richness and abundance directly diminished with retention degree (OGF > AR > DR > CC) due to incoming species cannot compensate the lost of them. However, fluctuations in diversity were observed along the YAH. Therefore, harvesting reduces insect richness in N. pumilio forests independently of the treatment, but the original insect assemblage significantly changes due to loss of sensitive species and introduction of others from surrounding environments. Despite this, inclusion of aggregates greatly diminished harvesting impacts because insect assemblage is favoured when structural complexity is preserved, conserving richness and abundance at similar levels than in old-growth forests. However, more studies are necessary to evaluate effects of different aggregate size, shape and distribution into harvested forests, as well as their fragmentation and connectivity at landscape level. © 2014 Springer International Publishing Switzerland.

Martinez O.G.,CONICET | Tanco M.E.,CONICET | Prada C.,Complutense University of Madrid | Guerra R.,Administracion de Parques Nacionales
Nordic Journal of Botany | Year: 2014

The gametophytic morphology and development of Alsophila odonelliana (Alston) Lehnert, have been studied through in vitro cultures. This species grows in southern Bolivia and northwestern Argentina. The spores are uniform in structure, but not in size; a certain percentage being smaller than the average. 16 spores per sporangium were found. The germination is of the Cyathea type. It was found that spores stored at 4°C can maintain their viability for over two years. The maximum value of germination depends on spore age. The filamentous gametophytes are 4-16 cells long. Young gametophytes have 1-2 branches that give rise to new gametophytes. Male, female, bisexual and neuter gametophytes were found. Propagules were frequently found in neuter gametophytes, and female and bisexual gametophytes were found to have chlorophyll containing scales. The antheridia are made up of five cells and produce non-viable spermatozoids. The archegonia have necks formed by four columns with four cells each. Most of the gametophytic phase is documented with photomicrographs. © 2014 The Authors.

Cuyckens G.A.E.,CONICET | Cuyckens G.A.E.,National University of Jujuy | Perovic P.G.,Administracion de Parques Nacionales | Cristobal L.,Fundacion ProYungas
Journal of Arid Environments | Year: 2015

Determining the geographic range of species is a main objective in ecology and has implications for conservation. Key determinants of carnivore distribution in dry environments are competition and the availability of water. Here, we gathered and mapped the available information on carnivore habitat quality in the high Andes and Puna in the extreme north of Argentina. We investigated four carnivore species: the Andean cat (Leopardus jacobita), the Pampas cat (Leopardus colocolo), the cougar (Puma concolor) and the culpeo fox (Lycalopex culpaeus). We assessed the main determinants of their distribution, testing explicitly for the effects of seasonal and temporal wetlands and biological interactions. We used species distribution models, and created biophysical models using environmental and landscape variables. Then, by including the four species' biophysical models into the model of the focal species, we tested for the importance of biological interactions. Wetlands were most important for the culpeo fox, most likely because it uses aquatic birds as prey. The cougar was the least restricted species in this arid environment, perhaps due to its large home range. In general, environmental variables, distances to wetlands and the annual range of temperature defined species' distributions better than did biological interactions. Only the distribution of the Andean cat, a specialized species, was influenced by biological interactions with the Pampas cat. © 2014 Elsevier Ltd.

Chemes S.B.,National University of Santa | Chemes S.B.,CONICET | Giraudo A.R.,National University of Santa | Giraudo A.R.,CONICET | Gil Y.,Administracion de Parques Nacionales
Mastozoologia Neotropical | Year: 2010

It was analyzed the diet of the Lontra longicaudis in El Rey National Park, within the Yungas forest eco-region, in the Argentine Northwest. Our data was compared with that from other populations previously studied in the Iberá Lagoon (Iberá marshes) and the Iguazú River (Paranaense forest) in the Argentine Northeast. We analyzed 130 feces from 37 latrines. Percentage of occurrence, relative frequency, percentage of relative importance and Levin's diversity were analyzed. We compared our results with those from other populations by means of the percentage similarity index, the re-sampling by bootstrapping and non-parametric analysis. We recorded 623 prey items. Fish, insects and crustaceans were more frequently consumed than amphibians, mollusks, reptiles and mammals. The majority of preys were benthonic organisms. Our results were more similar to the ones obtained in the Iberá Lagoon. Other studies in the Iberá and the Iguazú, published by the same author, were more similar between themselves. Differences in trophic adaptability, availability, temporal variation of preys or methodological biases among authors could be possible reasons for the diet differences of the populations studied in Argentina. © SAREM, 2010.

Giraudo A.R.,CONICET | Vidoz F.,Administracion de Parques Nacionales | Arzamendia V.,CONICET | Nenda S.J.,Museo Argentino de Ciencias Naturales Bernardino Rivadavia
Check List | Year: 2012

We revisit the distribution and natural history data of Tachymenis chilensis chilensis (Schlegel, 1837) in Argentina based on compiled and novel records, extending its northern and southern distribution from the previously known localities in Argentina. We recorded two prey items in Argentinean populations: Rhinella rubropunctata, reported for the first time, and Liolaemus pictus. Tachymenis c. chilensis is mainly found in forested habitats, generally near wetlands with abundant populations of amphibians. The latitudinal range occupied by T. c. chilensis in Argentina is similar to that in Chile, but its northern distribution limit reaches the lowest latitudes in Chile. This is probably due to the higher humidity levels in the western slopes of the Andes and the barrier effect of the highest mountain ranges in this area. © 2012 Check List and Authors.

Discover hidden collaborations