8 results on '"ARAGÓN, ROXANA"'
Search Results
2. The role of bioclimatic features, landscape configuration and historical land use in the invasion of an Asian tree in subtropical Argentina
- Author
-
Montti, Lia, Carrillo, Verónica Piriz, Gutiérrez-Angonese, Jorgelina, Gasparri, N. Ignacio, Aragón, Roxana, and Grau, H. Ricardo
- Published
- 2017
- Full Text
- View/download PDF
3. Fungal decomposers of leaf litter from an invaded and native mountain forest of NW Argentina
- Author
-
Fernandez, Romina Daiana, Bulacio, Natalia, Álvarez, Analía, Pajot, Hipólito, and Aragón, Roxana
- Published
- 2017
- Full Text
- View/download PDF
4. Soil enzymes associated with carbon and nitrogen cycling in invaded and native secondary forests of northwestern Argentina
- Author
-
Aragón, Roxana, Sardans, Jordi, and Peñuelas, Josep
- Published
- 2014
- Full Text
- View/download PDF
5. Leaf litter decomposition of the most abundant native and exotic woody species in the piedmont of Yungas forest, Tucumán, Argentina
- Author
-
Fernandez, Romina Daiana and Aragón, Roxana
- Subjects
purl.org/becyt/ford/1 [https] ,Bolsas de descomposición ,Ciencias Biológicas ,Constante de descomposición ,Plantas exóticas ,Yungas ,Ecología ,purl.org/becyt/ford/1.6 [https] ,Ligustrum lucidum ,CIENCIAS NATURALES Y EXACTAS - Abstract
Las especies exóticas pueden impactar en el proceso de descomposición, ya sea de manera directa (diferencias en calidad y/o cantidad de hojarasca) o de manera indirecta (modificando las condiciones micro ambientales y la abundancia y/o actividad de descomponedores). Los objetivos de este trabajo fueron: I) comparar la descomponibilidad de las especies exóticas y nativas más abundantes de los bosques secundarios del pedemonte de la Sierra de San Javier, Tucumán, II) analizar el efecto de las condiciones micro ambientales sobre la tasa de descomposición de un sustrato común y III) evaluar el efecto del tamaño de malla de las bolsas de descomposición en la descomposición de hojarasca. Para ello incubamos hojarasca de 7 especies nativas y 7 exóticas bajo condiciones estándares durante un año y hojarasca de Populus deltoides (sustrato común) en parches de bosques secundarios nativos e invadidos por Ligustrum lucidum en bolsas con dos tamaños de malla. La pérdida de peso no fue diferente entre el conjunto de especies nativas y exóticas pero si se encontraron diferencias interespecíficas. La constante de descomposición del sustrato común fue menor en los bosques invadidos por lo que L. lucidum modificaría la composición y/o actividad de organismos descomponedores y generaría cambios en las condiciones micro ambientales que determinan la descomposición. Por otra parte, la descomposición fue mayor en bolsas con malla grande, lo cual podría deberse al acceso de macro invertebrados. Nuestros resultados sugieren la ausencia de un patrón de descomposición en el conjunto de especies nativas y exóticas y la potencial influencia que tendría L. lucidum en los factores que controlan la descomposición. Exotic species may influence the process of decomposition, either directly (through differences in the quality and/or quantity of leaf-litter) or indirectly (by altering microclimatic conditions and the abundance and/or activity of decomposers). The aims of our study were: I) to compare the decomposability of the most abundant exotic and native species in secondary forests of the Sierra de San Javier, Tucumán, II) to assess the effect of microenvironemtal conditions on the rate of decomposition of an homogeneous substrate and III) to evaluate the effect of the litterbags mesh size on the decomposition process. To do this, we incubated leaf-litter of 7 native and 7 exotic species under standard conditions for one year and also leaf-litter of Populus deltoides (homogeneous substrate) in native and invaded by Ligustrum lucidum secondary forest patches in bags with two mesh sizes. Native and exotic species did not differ in their weight loss rates, but there were interspecific differences. The decay constant of the homogeneous substrate was lower in invaded patches so it is possible that L. lucidum modify the composition and /or activity of decomposing organisms and generate changes in micro-environmental conditions. In addition, decomposition was higher in bags with larger mesh size. This pattern may be explained by the differential access of macro invertebrates. Our results suggest the absence of a pattern of decay in native and exotic species as groups, and the potential influence that L. lucidum would have over the factors controlling littler decomposition. Fil: Fernandez, Romina Daiana. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Aragón, Roxana. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
- Published
- 2014
6. Invasion by Ligustrum lucidum (Oleaceae) in NW Argentina: early stage characteristics in different habitat types
- Author
-
Aragón, Roxana and Groom, Martha
- Subjects
secondary forest ,gaps ,biological invasions ,Ligustrum ,Population Dynamics ,Argentina ,ligustrum lucidum ,Germination ,Ligustrum lucidum ,Survival Analysis ,lcsh:Biology (General) ,montane forest ,Seeds ,forest edges ,Seasons ,Biological invasions ,lcsh:QH301-705.5 ,exotic species - Abstract
Currently biological invasions are considered one of the world’s most serious conservation problems. Ligustrum lucidum is the most abundant exotic tree in secondary forest patches of montane forests of NW Argentina. We studied the determinants of success of the early stages of its life cycle in distinct habitat types, with the hope of identifying vulnerabilities that could be exploited to control the invasion. Seed arrival, germination, seedling recruitment and survival, and sapling growth were studied in edges, gaps and forest interior. Seed arrival was also assessed under perches and in open fields. Germination was studied in forest and grass-land patches. L. lucidum seedling survival and sapling growth were compared with the most abundant native species survival and growth. Seed arrival was strongly seasonal with a peak in mid-August. Seed rain did not differ significantly among habitat types, however there was a tendency for edges to receive more seeds when only dispersed seeds were considered. Perches strongly enhanced seed arrival; more than 40 times the number of seeds were dispersed beneath citrus plants (i.e. perches) than found in paired open areas. In the forest, seeds in gaps and edges had higher germination rates, but there was no difference in seedling survival. Fruits under closed canopy exhibited the lowest germination. Germination and survival were low in open areas. Neither seedling recruitment nor sapling growth differed between gaps and forest interior. L. lucidum saplings grew significantly more than saplings of the most common native species, and also showed higher seedling survival. L. lucidum is a prolific fruit producer, is capable of germinating and surviving in a broad range of forest environments, it is relatively shade tolerant and has higher survival and faster growth rate in comprison to the most common native species. All these characteristics highlight its potency as a successful invader, and point to few vulnerabilities that could be targets of control measures.Las invasiones biológicas son consideradas actualmente uno de los problemas de conservación más serios. Ligustrum lucidum es el árbol exótico mas abundante en los bosques secundarios del NO de Argentina. Estudiamos llegada de semillas, germinación, reclutamiento y crecimiento de renovales en claros, bordes e interior del bosque La llegada de semillas también se estudió bajo perchas y en sitios abiertos. La supervivencia y el crecimiento de renovales de L. lucidum fueron comparados con los de las especies nativas mas abundantes. El arribo de semillas fue estacional y los bordes mostraron una tendencia a recibir mas semillas dispersadas. La presencia de perchas aumentó la llegada de semillas. Dentro del bosque, las semillas germinaron mas en claros y bordes, pero no hubo diferencia en sobrevivencia. La germinación y la supervivencia fue baja en sitios abiertos. El reclutamiento y crecimiento de renovales no difirió entre claros e interior del bosque. Los renovales de L. lucidum crecieron mas que los renovales de las especies nativas mas comunes. L. lucidum se establece y sobrevive en un amplio rango de condiciones, es relativamente tolerante a la sombra y tiene una rápida tasa de crecimiento. Estas características indican su capacidad invasora, y señalan escasas vulnerabilidades que puedan ser usadas para su control.
- Published
- 2004
- Full Text
- View/download PDF
7. Descomposición de hojarasca de las especies leñosas nativas y exóticas más abundantes del pedemonte de las Yungas, Tucumán, Argentina.
- Author
-
FERNÁNDEZ, ROMINA D. and ARAGÓN, ROXANA
- Abstract
Exotic species may influence the process of decomposition, either directly (through differences in the quality and/or quantity of leaf-litter) or indirectly (by altering microclimatic conditions and the abundance and/or activity of decomposers). The aims of our study were: I) to compare the decomposability of the most abundant exotic and native species in secondary forests of the Sierra de San Javier, Tucumán, II) to assess the effect of microenvironemtal conditions on the rate of decomposition of an homogeneous substrate and III) to evaluate the effect of the litterbags mesh size on the decomposition process. To do this, we incubated leaf-litter of 7 native and 7 exotic species under standard conditions for one year and also leaf-litter of Populus deltoides (homogeneous substrate) in native and invaded by Ligustrum lucidum secondary forest patches in bags with two mesh sizes. Native and exotic species did not differ in their weight loss rates, but there were interspecific differences. The decay constant of the homogeneous substrate was lower in invaded patches so it is possible that L. lucidum modify the composition and /or activity of decomposing organisms and generate changes in micro-environmental conditions. In addition, decomposition was higher in bags with larger mesh size. This pattern may be explained by the differential access of macro invertebrates. Our results suggest the absence of a pattern of decay in native and exotic species as groups, and the potential influence that L. lucidum would have over the factors controlling littler decomposition. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
8. Exotic species as modifiers of ecosystem processes: Litter decomposition in native and invaded secondary forests of NW Argentina.
- Author
-
Aragón, Roxana, Montti, Lia, Ayup, María Marta, and Fernández, Romina
- Subjects
- *
PLANT litter decomposition , *INTRODUCED species , *ECOSYSTEMS , *SECONDARY forests - Abstract
Abstract: Invasions of exotic tree species can cause profound changes in community composition and structure, and may even cause legacy effect on nutrient cycling via litter production. In this study, we compared leaf litter decomposition of two invasive exotic trees (Ligustrum lucidum and Morus sp.) and two dominant native trees (Cinnamomum porphyria and Cupania vernalis) in native and invaded (Ligustrum-dominated) forest stands in NW Argentina. We measured leaf attributes and environmental characteristics in invaded and native stands to isolate the effects of litter quality and habitat characteristics. Species differed in their decomposition rates and, as predicted by the different species colonization status (pioneer vs. late successional), exotic species decayed more rapidly than native ones. Invasion by L. lucidum modified environmental attributes by reducing soil humidity. Decomposition constants (k) tended to be slightly lower (−5%) for all species in invaded stands. High SLA, low tensile strength, and low C:N of Morus sp. distinguish this species from the native ones and explain its higher decomposition rate. Contrary to our expectations, L. lucidum leaf attributes were similar to those of native species. Decomposition rates also differed between the two exotic species (35% higher in Morus sp.), presumably due to leaf attributes and colonization status. Given the high decomposition rate of L. lucidum litter (more than 6 times that of natives) we expect an acceleration of nutrient circulation at ecosystem level in Ligustrum-dominated stands. This may occur in spite of the modified environmental conditions that are associated with L. lucidum invasion. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.