Biblioteca Digital Instituto Forestal
Not a member yet
23986 research outputs found
Sort by
Extubocellulus spinifer (Hargraves & Guillard) Hasle, Stosch & Syvertsen (Cymatosiraceae, Bacillariophyceae): First report of the species from the Southeastern Pacific with comments on the variability of some of its morphological features
No full textDuring the taxonomic analysis of strains from marine phytoplankton samples, it was found that a sample contained isolated or short chains of 2-4 small cells. Observations under the electron microscopes revealed the presence of Extubocellulus spinifer (Hargraves & Guillard) Hasle, Stosch & Syvertsen, a minute species until now not reported for the Southeastern Pacific Ocean. In this paper we describe the characteristics of the Chilean cells, comment on the variability of some of its morphological features, and discuss about the differences between the two known species of the genus
NITROGEN RUNOFF AND LEACHING LOSSES IN BEEF PRODUCTION SYSTEMS UNDER TWO DIFFERENT STOCKING RATES IN SOUTHERN CHILE
No full textThe Lakes Region of Chile produces 60% of the country's milk and 45% of its meat. Production is expected to increase in the near future, yet there are few data on the environmental impact of local livestock systems. A field experiment was carried out during 2004 to measure nitrogen (N) runoff and leaching losses in beef cattle-grazing production systems near Osorno. Grazing was carried out with Holstein-Friesian steers of 220 kg of initial live weight, with stocking rates of 3.5 and 5 steers ha-1. Water samples were collected during 6.5 months with surface lysimeters and ceramic cups, and were analyzed for nitrate and ammonium. Total losses were calculated as the product of N concentration and accumulated drainage at each sampling date. A significant difference in the total N loss was found between the two treatments (11.1 and 29.9 kg N ha-1, respectively; P < 0.05). The main pathway of N loss was leaching, which contributed 99% of the total N loss. Nitrate was the main form of N loss in runoff (71%) and leaching (99%). Average nitrate concentration in leaching samples was always below the European Community Directive limit. However, nitrate concentration in runoff samples had maximum values of 116 ± 13.8 and 82 ± 22.4 mg L-1 for the 3.5 and 5 steers ha-1 treatments, respectively. For the experimental conditions tested, N losses from beef cattle production systems were low. This was related to the low N inputs in fertilizers used and to the physical and chemical properties of the volcanic soil
ESPEJOS DE NUESTRA EPOCA: BIODIVERSIDAD, SISTEMATICA Y EDUCACION
No full textLa biología ha definido la biodiversidad como la variedad y variabilidad de los seres vivos y de los ecosistemas que integran. Los componentes de la diversidad biológica se organizan en tres niveles: el de los genes, que constituyen las bases moleculares de la herencia; el de las especies, que son conjuntos de organismos afines capaces de reproducirse entre sí; y el de los ecosistemas, que son complejos funcionales formados por los organismos y el medio físico en el que habitan. La biodiversidad es el resultado de un proceso que comenzó hace 3.500 millones de años, cuando en las aguas de un mar primitivo empezaron a formarse moléculas complejas capaces de autoduplicarse. Todos los seres que hoy viven en la Tierra comparten esa misteriosa herencia molecular. En las últimas décadas numerosas especies de plantas y animales desaparecen de la faz de la tierra, a un ritmo tal que a fines del siglo XXI habrán desaparecido 2/3 de todas las especies. Dada la gravedad del problema está justificado reflexionar acerca de esta pérdida y sus consecuencias como espejos de nuestra época y relacionarlas con las tareas de la sistemática biológica y la educació
Estudio florístico del Area Marina Costera Protegida Francisco Coloane, Región de Magallanes, Chile
No full textUn factor clave para generar políticas de conservación y de manejo de un área protegida es el conocimiento detallado de su biodiversidad. En este trabajo documentamos la flora vascular del Área Marina Costera Protegida Francisco Coloane representada por 55 familias, 92 géneros y 120 especies. De ellas 69 son endémicas para Chile y Argentina. Las familias más diversas son: Asteraceae (11 géneros/15 especies), Poaceae (10 /13) y Cyperaceae (6 /12). Los géneros mejor representados son Carex con 5 especies y Senecio con 4, mientras que 72 géneros están representados por una sola especie. La forma de vida dominante son las hierbas (74 especies, 62%), seguidas de los subarbustos (19 especies, 16%). Dos especies son nuevos registros para la Región de Magallanes (Lupinus arboreus y Gamochaeta montícola). El 95% de la flora corresponde a especies nativas y un 5% a especies introducidas naturalizadas. Sólo 9 especies presentan problemas de conservación
Nueva especie de Loasa (Loasaceae) de Chile
No full textLoasa mollensis Muñoz-Schick et Trenqualye is described as a new species. It is apparently narrowly endemic to a small area in the coast of the Valparaiso region, central Chile. The species has small yellow flowers and infer rounded capsules containing large seeds
Deforestation patterns shape population structure of the Magellanic Woodpecker (Campephilus magellanicus) in southern Chile
No full textOne important landscape-scale consequence of deforestation is reduced connectivity, which has the potential to isolate
populations in ways that affect genetic diversity and population structure. Among the many regions of the world where this scenario
has played out is the South American temperate forest (SATF) in southern Chile, and there is now strong concern about the population
viability of forest taxa. We studied one such species, the Magellanic Woodpecker (Campephilus magellanicus), a forest specialist that
is now listed as vulnerable in parts of its range in Chile. We characterized genetic variability and population structure from 33 samples
of Magellanic Woodpeckers from two large but isolated populations in Nahuelbuta National Park in the Coastal mountain range
and the Conguillío National Park in the Andes using ddRAD-seq method. We found lower genetic variability in Nahuelbuta than
Conguillío, but inbreeding values (FIS) did not show evidence for inbreeding depression. Results suggest the presence of two genetic
clusters, with an average FST value of 0.04. Phylogenetic analysis showed that the Nahuelbuta population forms a clade that is nested
within the individuals from Conguillío, suggesting limited gene flow between these populations. Our results support the idea that
extensive deforestation has played a role in shaping the genetic patterns that we have identified. Because of this, we emphasize the
need for regional planning to increase the structural connectivity between fragments of mature native forests, to provide an opportunity
for the persistence of Magellanic Woodpeckers in this region.Une conséquence importante de la déforestation à l'échelle du paysage est la diminution de la connectivité, qui peut à
son tour entraîner l'isolement des populations jusqu'à affecter leur diversité génétique et leur structure. La Forêt tempérée d'Amérique
du Sud dans le sud du Chili figure parmi les nombreuses régions du monde où ce scénario s'est produit, et on s'inquiète désormais
fortement de la viabilité des populations des taxons forestiers qui s'y trouvent. Nous avons étudié une de ces espèces, le Pic de Magellan
(Campephilus magellanicus), spécialiste des forêts maintenant classé comme vulnérable dans certaines parties de son aire de répartition
au Chili. Nous avons caractérisé la variabilité génétique et la structure de la population à partir de 33 échantillons de Pics de Magellan
provenant de deux populations importantes mais isolées, dans le parc national de Nahuelbuta dans la chaîne de montagnes côtières
et dans le parc national de Conguillío dans les Andes au moyen de la méthode ddRAD-seq. Nous avons trouvé une variabilité
génétique plus faible à Nahuelbuta qu'à Conguillío, mais les valeurs de consanguinité (FIS) n'ont pas montré de signes de dépression
de la consanguinité. Nos résultats indiquent la présence de deux groupes génétiques et une valeur FIS moyenne de 0,04. L'analyse
phylogénétique a révélé que la population de Nahuelbuta forme un clade imbriqué dans les individus de Conguillío, laissant entendre
qu'il existe un flux génétique limité entre ces populations. Nos résultats corroborent l'idée voulant que la déforestation extensive a
joué un rôle dans la formation des modèles génétiques que nous avons identifiés. Nous croyons donc qu'il est nécessaire de planifier
régionalement pour accroître la connectivité structurelle entre les fragments de forêts indigènes matures, afin d'assurer la pérennité
du Pic de Magellan dans cette région
Asymbiotic germination in three Chloraea species (Orchidaceae) from Chile
No full textABSTRACT Orchids require symbiotic fungi and/or specific conditions to germinate. Asymbiotic techniques have been shown successful for orchid germination. In Chile, Chloraea include many endemic, and potentially ornamental, terrestrial orchid species. In this study, individuals of Chloraea crispa, C. gavilu and C. virescens were manually autopollinated. The resulting capsules were sterilized and seeds were aseptically obtained. We evaluated asymbiotic germination in: Agar Water (AW), Knudson C (KC), Banana Culture Media (CMB), Tomato Culture Media (CMT), Malmgren Modified (MM), Murashige and Skoog (MS), and MS modified (MS1/2). Seeds were incubated in the dark at 24±1 ºC for 2 weeks. Then they were put in 16/8 h light/dark cycles for 14 weeks. We registered germination and embryo development in the different culture media. After 8 weeks, all tested Chloraea species germinated in most culture media. After 16 weeks, embryos in MM showed an evident shoot. In AW only the pre-germination stage was achieved. In C. gavilu germination was over 90% in MM, CMT, and CMB. In KC, a lower germination was obtained in all tested species compared to the other culture media, except for AW. Asymbiotic germination of endemic Chilean orchids could be a viable strategy for their conservation and propagation as ornamental species
EL CARIOTIPO DE LAPAGERIA ROSEA RUIZ ET PAV. (LILIALES: PHILESIACEAE)
No full textLapageria rosea Ruiz et Pav. showed an asymmetric and bimodal karyotype 2n = 2x = 30, with three metacentric, six submetacentric and six subtelocentric chromosome pairs. One B chromosome pair was also observed. The total chromosome length (2n) was 131.3 + 0.22 µ
Botánica Forense en Chile: El caso de Aristotelia chilensis (Molina) Stuntz y su potencial utilidad como especie bioindicadora forense
No full textAristotelia chilensis is mentioned for the first time for plants grown on pig carcasses decomposing. Its potential as a bioindicator species for the development of forensic botany in Chile and its importance in the reconstruction of criminal events are discussed
