Browsing by Author "Gutierrez, Julio R."

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    Long-term research in Bosque Fray Jorge National Park: Twenty years studying the role of biotic and abiotic factors in a Chilean semiarid scrubland
    (2010) Gutierrez, Julio R.; Meserve, Peter L.; Kelt, Douglas A.; Engilis, Andrew, Jr.; Previtali, M. Andrea; Milstead, W. Bryan; Jaksic, Fabian M.
    Since 1989, we have conducted a large-scale ecological experiment in semiarid thorn scrub of a national park in north-central Chile. Initially, we focused on the role of biotic interactions including predation, interspecific competition, and herbivory in small mammal and plant components of the community. We utilized a reductionist approach with replicated 0.56 ha fenced grids that selectively excluded vertebrate predators and/or larger small mammal herbivores such as the degu, Octodon degas. Although we detected small transitory effects of predator exclusions on degu survival and numbers, other species failed to show responses. Similarly, interspecific competition (i.e., degus with other small mammals) had no detectable numerical effects (although some behavioral responses occurred), and degu-exclusions had relatively small effects on various plant components. Modeling approaches indicate that abiotic factors play a determining role in the dynamics of principal small mammal species such as O. degas and the leaf-eared mouse (Phyllotis darwini). In turn, these are mainly related to aperiodic pulses of higher rainfall (usually during El Nino events) which trigger ephemeral plant growth; a food addition experiment. in 1997-2000 verified the importance of precipitation as a determinant of food availability. Since 2004, we have expanded long-term monitoring efforts to other important community components including birds and insects in order to understand effects of abiotic factors on them; we report some of the first results of comprehensive surveys on the former in this region. Finally, we recently shifted focus to documenting effects of exotic lagomorphs in the park. We installed additional treatments selectively excluding small mammals, lagomorphs, or both, from replicated grids in order to evaluate putative herbivore impacts. In conjunction with increased annual rainfall since 2000, we predict that introduced lagomorphs will have increasing impacts in this region, and that more frequent El Ninos in conjunction with global climatic change may lead to marked changes in community dynamics. The importance of long-term experimental studies is underscored by the fact that only now after 20 years of work are some patterns becoming evident.
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    Progress in creating a joint research agenda that allows networked long-term socio-ecological research in southern South America: Addressing crucial technological and human capacity gaps limiting its application in Chile and Argentina
    (WILEY, 2012) Anderson, Christopher B.; Celis Diez, Juan L.; Bond, Barbara J.; Martinez Pastur, Guillermo; Little, Christian; Armesto, Juan J.; Ghersa, Claudio; Austin, Amy; Schlichter, Tomas; Lara, Antonio; Carmona, Martin; Chaneton, Enrique J.; Gutierrez, Julio R.; Rozzi, Ricardo; Vanderbilt, Kristin; Oyarce, Guillermo; Fernandez, Roberto J.
    Since 1980, more than 40 countries have implemented long-term ecological research (LTER) programs, which have shown their power to affect advances in basic science to understand the natural world at meaningful temporal and spatial scales and also help link research with socially relevant outcomes. Recently, a disciplinary paradigmatic shift has integrated the human dimensions of ecosystems, leading to a long-term socio-ecological research (LTSER) framework to address the world's current environmental challenges. A global gap in LTER/LTSER only exists in the latitudinal range of 40-60 degrees S, corresponding to Argentina and Chile's temperate/sub-Antarctic biome. A team of Chilean, Argentine and US researchers has participated in an ongoing dialogue to define not only conceptual, but also practical barriers limiting LTER/LTSER in southern South America. We have found a number of existing long-term research sites and platforms throughout the region, but at the same time it has been concluded an agenda is needed to create and implement further training courses for students, postdoctoral fellows and young scientists, particularly in the areas of data and information management systems. Since LTER/LTSER efforts in Chile and Argentina are incipient, instituting such courses now will enhance human and technical capacity of the natural science and resource community to improve the collection, storage, analysis and dissemination of information in emerging LTER/LTSER platforms. In turn, having this capacity, as well as the ongoing formalization of LTER/LTSER programs at national levels, will allow the enhancement of crucial collaborations and comparisons between long-term research programs within the region and between hemispheres and continents. For Spanish version of the entire article, see Online Supporting Information (Appendix S1). Resumen Desde 1980, mas de cuarenta paises han implementado programas de Investigacion Ecologica a Largo Plazo (LTER por sus siglas en ingles), los cuales han mostrado su capacidad para influir sobre los avances en las ciencias basicas que permiten entender el mundo natural en escalas temporales y espaciales significativas, y tambien ayudar a enfocar la investigacion hacia estudios socialmente relevantes. Recientemente, gracias a un cambio de paradigma en la disciplina, se integro tambien la dimension humana de los ecosistemas, llevandola a un marco conceptual de Investigacion Socio-Ecologica a Largo Plazo (LTSER por sus siglas en ingles) para enfrentar los desafios medio-ambientales del mundo actual. Existe un vacio global en LTER/LTSER en el rango latitudinal de 40-60 degrees S, correspondiente a los biomas templados/subantarticos de Argentina y Chile. Un equipo de investigadores chilenos, argentinos y estadounidenses ha trabajado por varios anos para definir cuales son la barreras que actualmente limitan la creacion de una Red de LTER/LTSER en el sur de Sudamerica, no solamente en terminos conceptuales, sino tambien a nivel practico. Existe un buen numero de sitios de investigacion a largo plazo en la region, pero tambien concluimos que es necesario crear e implementar mas cursos de capacitacion para estudiantes, investigadores post-doctorales y jovenes cientificos, particularmente en las areas de sistemas de manejo de datos e informacion.