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Papers by Javier Sanguinetti

and propose guidelines to be considered in the management of the species that will favor its cont... more and propose guidelines to be considered in the management of the species that will favor its control and not its expansion.

Coarse woody debris (CWD) is an important element driving ecological processes, strengthening eco... more Coarse woody debris (CWD) is an important element driving ecological processes, strengthening ecosystem resilience and for biodiversity within forest ecosystems. However, the abundance and distribution of CWD and their relation to natural and human factors are poorly known in southern South America. In this work we studied the density and volume of CWD types in Nothofagus–Araucaria stands in northern Patagonia (Neuqu en – Argentina) and relationships with forest composition and structure. We also studied their relationships with fire history, topography and human-related variables. Twenty-three stands with Nothofagus pumilio, Nothofagus antarctica and/or Araucaria araucana were sampled to estimate quantities of logs, snags and dead branches using the planar-intersect method. CWD density and volume in these forests were moderate and varied across the landscape with a spatial pattern determined by biotic, abiotic and human use–related variables. Mean CWD volume was 52.9 m 3 ha À1 (range: 1.6–143.7) and significantly varied among forest types and watersheds. CWD was positively related to dbh, tree height and slope, but negatively related to tree density. CWD was clearly influenced by composition and structural characteristics of stands, where the tree species traits had an important role. As well, the observed amount and type of CWD, whereby most of the stands showed low levels of old (pre-disturbance) logs/snags and poor new inputs of deadwood, may be explained by fire frequency. Firewood gathering and livestock grazing negatively affected deadwood stocks and topography counteracts this effect by limiting human access. Fire disturbance history, windthrow and dieback pulses produced by insect outbreaks and human access seemed to be the main causes that best explained CWD spatial distribution and abundance patterns in northwestern Patagonian forests.

Oryx, 2009

Have Patagonian waterfowl been affected by the introduction of the American mink Mustela vison? S... more Have Patagonian waterfowl been affected by the introduction of the American mink Mustela vison? S a l v a d o r J . P e r i s , J a v i e r S a n g u i n e t t i and M o i s É s P e s c a d o r Abstract The American mink Mustela vison has spread widely beyond its native North American range and is associated with problems for the conservation of native species because of its impact as both predator and competitor. We investigated the impact of feral mink on waterfowl in Lanín National Park, south-west Neuquén, Patagonia, Argentina, an area in which the predator is currently expanding. Statistically significant differences were observed in the number of waterfowl species at lakes without mink (7.3 -SE 0.7) compared to those with mink (4.0 -SE 0.6). Overall abundance of birds observed per day was higher at lakes without (104.2 -SE 20.6) than with mink (21.2 -SE 22.3). The great grebe Podiceps major, speckled teal Anas flavirostris, Chiloe wigeon Anas sibilatrix and red-gartered coot Fulica armillata were more abundant on water bodies without mink, and flocks of the ashy-headed goose Chloephaga poliocephala were larger in areas without mink. Other species, such as the white-tufted grebe Rollandia rolland, coscoroba swan Coscoroba coscoroba, black-necked swan Cygnus melanocoryphus, cinnamon teal Anas cyanoptera, Andean duck Oxyura jamaicensis and Andean gull Larus serranus were never observed in areas harbouring mink. We conclude that at least 12 of the 25 waterfowl species observed are sensitive to the presence of the mink, either being absent or having a lower abundance where mink are present.

in spring of 2000, Chusquea culeou bamboo, the dominant understory plant in Valdivian forest habi... more in spring of 2000, Chusquea culeou bamboo, the dominant understory plant in Valdivian forest habitat in southwestern argentina, flowered over a latitudinal range of 100 km and produced a massive amount of seed. reproductive activity of rodents in the area continued into the subsequent autumn and winter, when rodent numbers reached peak levels and large numbers of drowned rodents appeared

Ecología Austral, Aug 1, 2014

Las especies exóticas invasoras amenazan la biodiversidad. Existen diferentes opciones para su ma... more Las especies exóticas invasoras amenazan la biodiversidad. Existen diferentes opciones para su manejo: prevención, detección temprana, erradicación, control, exclusión e incluso la “no acción”. A mayor complejidad de manejo, más información se requiere para ejecutarlo exitosamente. Además, gestores e investigadores abordan la problemática con enfoques e intereses diferentes. Mientras los primeros priorizan acciones de manejo, los segundos encuentran una oportunidad para estudiar aspectos básicos y/o teóricos, no siempre aplicados al manejo. La gestión de estas especies ofrece una ocasión única para que ambos grupos trabajen juntos en busca de beneficios mutuos. Actualmente, las decisiones de manejo suelen basarse en experiencias o información de otros países, no siempre adaptables a la problemática local. En este trabajo presentamos varias experiencias de manejo en la Administración de Parques Nacionales para exponer logros, dificultades y desafíos a los que usualmente se enfrenta la gestión institucional. Encontramos que: a) ante recursos escasos es
importante generar herramientas de priorización efectivas y redes de trabajo; b) es imprescindible involucrar a la comunidad en las acciones de manejo; c) se requieren investigaciones aplicadas al manejo específico; y d) es necesario una detallada planificación previa y un monitoreo de las acciones ejecutadas y de sus resultados, basados en información técnica de primer nivel, ya que son aspectos claves para un manejo exitoso. Finalmente, gestores e investigadores deben cerciorarse que los resultados de estas investigaciones aplicadas sean conocidos y comprendidos por los tomadores de decisiones y la opinión pública, para asegurar el apoyo a la gestión.

Revista chilena de historia natural, 2009

Efectos de la producción de semillas y la heterogeneidad vegetal sobre la supervivencia de semill... more Efectos de la producción de semillas y la heterogeneidad vegetal sobre la supervivencia de semillas y el patrón espacio-temporal de establecimiento de plántulas en Araucaria araucana Araucaria araucana temporal and spatial seedling establishment patterns: masting, seed predation and understory vegetation effects

Revista chilena de historia natural, 2008

Biological Invasions, 2010

Post-dispersal seed predation can severely limit plant recruitment, but its ultimate impact could... more Post-dispersal seed predation can severely limit plant recruitment, but its ultimate impact could be modulated by environmental factors and by the composition of the granivore guild. Here, we analyze the relative impact of the non-native wild boar and native rodents on seed survival and seedling establishment of the mast conifer Araucaria araucana. Predation, seed survival and seedling establishment were measured at different microsites and distances from 11 isolated trees in Lanín National Park (Argentina) over a period of marked fluctuation in seed production. Wild boar consumed between 10 and 30% of available seeds on a 13-day period, threefold less than rodents. Wild boar predation was mainly affected by forest canopy composition, while microsite conditions influenced both kind of predators, with high chronic rodent predation underneath dense vegetation and moderate (but interannually variable) wild boar predation at poorly vegetated microsites. Predation by rodents was spatially clustered at the microsite scale, particularly during non-mast years; while predation by wild boar was spatially structured at a coarser scale and less modified by masting. The exclusion of wild boar increased significantly the amount of surviving seeds, resulting in higher seedling establishment in intermediate production years, but not affecting it during the mast year. At tree level, seedling establishment was negatively correlated with predation; while at stand level, cone production accounted for most of the seedling establishment variability. The current wild boar population may not be affecting the seedling establishment at population scale, probably due to minimization of its impact by the Araucaria masting strategy. However, if wild boar population numbers continue to increase, their impact may shift from individual tree scale to stand scale, threatening Araucaria forest regeneration.

Austral Ecology, 2008

Masting, the intermittent and synchronous production of large seed crops, may result from either ... more Masting, the intermittent and synchronous production of large seed crops, may result from either of two major processes: resource matching and economy of scale. Components of cone production in Araucaria araucana were partitioned among populations and trees to ascertain the existence of masting and the processes involved. Cone production data from seven populations were obtained during a 9-year period and seed gathering data were available for an 18-year time series from six sites in an area of more than 7600 km 2 . Araucaria araucana showed environmentally triggered, intermittent, moderately fluctuating, and highly regionally synchronous reproduction.The mean pairwise correlations of cones production among populations and seed gathering sites were 0.89 and 0.74, respectively, suggesting synchrony in reproduction. Among trees we observed a mean correlation of 0.74 with values ranging from 0.66 to 0.81 for the analysed populations. The existence of negative autocorrelation in seed production between year 0 and year -2 at the individual tree level suggests the presence of 'switching' or internal resource allocation, thus discarding the Resource Matching hypothesis. Mean coefficient of variation (CVp) among populations was moderate (0.95) and similar to the modal CVp values reported in the published reports. Mean CVi among individual trees was 1.16, suggesting a large number of equally and synchronously fluctuating trees, rather than a few largely fluctuating individuals. These results suggest that pollination efficiency and/or predator satiation hypotheses could be responsible for the masting cycles in this conifer. Ancillary data about limitation of airborne pollen dispersion and temporal variation in the amount of seeds per cone and about seed predator satiation, also support both proposed mechanisms.

Lanín (Neuquén-Argentina) RESUMEN. Los estudios sobre producción de semillas en especies arbóreas... more Lanín (Neuquén-Argentina) RESUMEN. Los estudios sobre producción de semillas en especies arbóreas son importantes para la ciencia y para el manejo de los bosques nativos. En este trabajo se estudió la producción a largo plazo de conos de araucaria (Araucaria araucana), cuyas semillas son utilizadas como alimento por el ser humano, en poblaciones ubicadas en distinta exposición y altitud, y con diferente composición y estructura forestal. Se contaron conos en siete poblaciones del Parque Nacional Lanín (Neuquén, Argentina) durante 15 años (2000 a 2014), y se estimó la cantidad de conos y semillas por árbol, por hectárea y por población. Los años de máxima producción fueron . La producción media estimada de conos por árbol fue 19 (rango: 1-62); mientras que la de semillas fue 2372 (rango: 61-9287). La mayor variación temporal en la producción de semillas respecto a la de conos se debió a que hubo significativamente más semillas por cono en los años más productivos. El promedio estimado por hectárea fue de 685 conos, 89394 semillas y 273 kilos de semilla. Los bosques puros y densos de araucaria y los mixtos con lenga son, en promedio, al menos 2.5 y 1.5 veces más productivos que el resto de los bosques. El número de conos por árbol varío entre poblaciones y asociado principalmente con la exposición solar. Sin embargo, este efecto difiere según la productividad anual y el patrón observado estaría vinculado con el mecanismo de formación de yemas florales estimulado por la sequía. Estos resultados pueden utilizarse para planificar la conservación de estos bosques en Argentina y Chile frente a la mayor presión en la cosecha de semillas y por la presencia de granívoros introducidos.

and propose guidelines to be considered in the management of the species that will favor its cont... more and propose guidelines to be considered in the management of the species that will favor its control and not its expansion.

Coarse woody debris (CWD) is an important element driving ecological processes, strengthening eco... more Coarse woody debris (CWD) is an important element driving ecological processes, strengthening ecosystem resilience and for biodiversity within forest ecosystems. However, the abundance and distribution of CWD and their relation to natural and human factors are poorly known in southern South America. In this work we studied the density and volume of CWD types in Nothofagus–Araucaria stands in northern Patagonia (Neuqu en – Argentina) and relationships with forest composition and structure. We also studied their relationships with fire history, topography and human-related variables. Twenty-three stands with Nothofagus pumilio, Nothofagus antarctica and/or Araucaria araucana were sampled to estimate quantities of logs, snags and dead branches using the planar-intersect method. CWD density and volume in these forests were moderate and varied across the landscape with a spatial pattern determined by biotic, abiotic and human use–related variables. Mean CWD volume was 52.9 m 3 ha À1 (range: 1.6–143.7) and significantly varied among forest types and watersheds. CWD was positively related to dbh, tree height and slope, but negatively related to tree density. CWD was clearly influenced by composition and structural characteristics of stands, where the tree species traits had an important role. As well, the observed amount and type of CWD, whereby most of the stands showed low levels of old (pre-disturbance) logs/snags and poor new inputs of deadwood, may be explained by fire frequency. Firewood gathering and livestock grazing negatively affected deadwood stocks and topography counteracts this effect by limiting human access. Fire disturbance history, windthrow and dieback pulses produced by insect outbreaks and human access seemed to be the main causes that best explained CWD spatial distribution and abundance patterns in northwestern Patagonian forests.

Oryx, 2009

Have Patagonian waterfowl been affected by the introduction of the American mink Mustela vison? S... more Have Patagonian waterfowl been affected by the introduction of the American mink Mustela vison? S a l v a d o r J . P e r i s , J a v i e r S a n g u i n e t t i and M o i s É s P e s c a d o r Abstract The American mink Mustela vison has spread widely beyond its native North American range and is associated with problems for the conservation of native species because of its impact as both predator and competitor. We investigated the impact of feral mink on waterfowl in Lanín National Park, south-west Neuquén, Patagonia, Argentina, an area in which the predator is currently expanding. Statistically significant differences were observed in the number of waterfowl species at lakes without mink (7.3 -SE 0.7) compared to those with mink (4.0 -SE 0.6). Overall abundance of birds observed per day was higher at lakes without (104.2 -SE 20.6) than with mink (21.2 -SE 22.3). The great grebe Podiceps major, speckled teal Anas flavirostris, Chiloe wigeon Anas sibilatrix and red-gartered coot Fulica armillata were more abundant on water bodies without mink, and flocks of the ashy-headed goose Chloephaga poliocephala were larger in areas without mink. Other species, such as the white-tufted grebe Rollandia rolland, coscoroba swan Coscoroba coscoroba, black-necked swan Cygnus melanocoryphus, cinnamon teal Anas cyanoptera, Andean duck Oxyura jamaicensis and Andean gull Larus serranus were never observed in areas harbouring mink. We conclude that at least 12 of the 25 waterfowl species observed are sensitive to the presence of the mink, either being absent or having a lower abundance where mink are present.

in spring of 2000, Chusquea culeou bamboo, the dominant understory plant in Valdivian forest habi... more in spring of 2000, Chusquea culeou bamboo, the dominant understory plant in Valdivian forest habitat in southwestern argentina, flowered over a latitudinal range of 100 km and produced a massive amount of seed. reproductive activity of rodents in the area continued into the subsequent autumn and winter, when rodent numbers reached peak levels and large numbers of drowned rodents appeared

Ecología Austral, Aug 1, 2014

Las especies exóticas invasoras amenazan la biodiversidad. Existen diferentes opciones para su ma... more Las especies exóticas invasoras amenazan la biodiversidad. Existen diferentes opciones para su manejo: prevención, detección temprana, erradicación, control, exclusión e incluso la “no acción”. A mayor complejidad de manejo, más información se requiere para ejecutarlo exitosamente. Además, gestores e investigadores abordan la problemática con enfoques e intereses diferentes. Mientras los primeros priorizan acciones de manejo, los segundos encuentran una oportunidad para estudiar aspectos básicos y/o teóricos, no siempre aplicados al manejo. La gestión de estas especies ofrece una ocasión única para que ambos grupos trabajen juntos en busca de beneficios mutuos. Actualmente, las decisiones de manejo suelen basarse en experiencias o información de otros países, no siempre adaptables a la problemática local. En este trabajo presentamos varias experiencias de manejo en la Administración de Parques Nacionales para exponer logros, dificultades y desafíos a los que usualmente se enfrenta la gestión institucional. Encontramos que: a) ante recursos escasos es
importante generar herramientas de priorización efectivas y redes de trabajo; b) es imprescindible involucrar a la comunidad en las acciones de manejo; c) se requieren investigaciones aplicadas al manejo específico; y d) es necesario una detallada planificación previa y un monitoreo de las acciones ejecutadas y de sus resultados, basados en información técnica de primer nivel, ya que son aspectos claves para un manejo exitoso. Finalmente, gestores e investigadores deben cerciorarse que los resultados de estas investigaciones aplicadas sean conocidos y comprendidos por los tomadores de decisiones y la opinión pública, para asegurar el apoyo a la gestión.

Revista chilena de historia natural, 2009

Efectos de la producción de semillas y la heterogeneidad vegetal sobre la supervivencia de semill... more Efectos de la producción de semillas y la heterogeneidad vegetal sobre la supervivencia de semillas y el patrón espacio-temporal de establecimiento de plántulas en Araucaria araucana Araucaria araucana temporal and spatial seedling establishment patterns: masting, seed predation and understory vegetation effects

Revista chilena de historia natural, 2008

Biological Invasions, 2010

Post-dispersal seed predation can severely limit plant recruitment, but its ultimate impact could... more Post-dispersal seed predation can severely limit plant recruitment, but its ultimate impact could be modulated by environmental factors and by the composition of the granivore guild. Here, we analyze the relative impact of the non-native wild boar and native rodents on seed survival and seedling establishment of the mast conifer Araucaria araucana. Predation, seed survival and seedling establishment were measured at different microsites and distances from 11 isolated trees in Lanín National Park (Argentina) over a period of marked fluctuation in seed production. Wild boar consumed between 10 and 30% of available seeds on a 13-day period, threefold less than rodents. Wild boar predation was mainly affected by forest canopy composition, while microsite conditions influenced both kind of predators, with high chronic rodent predation underneath dense vegetation and moderate (but interannually variable) wild boar predation at poorly vegetated microsites. Predation by rodents was spatially clustered at the microsite scale, particularly during non-mast years; while predation by wild boar was spatially structured at a coarser scale and less modified by masting. The exclusion of wild boar increased significantly the amount of surviving seeds, resulting in higher seedling establishment in intermediate production years, but not affecting it during the mast year. At tree level, seedling establishment was negatively correlated with predation; while at stand level, cone production accounted for most of the seedling establishment variability. The current wild boar population may not be affecting the seedling establishment at population scale, probably due to minimization of its impact by the Araucaria masting strategy. However, if wild boar population numbers continue to increase, their impact may shift from individual tree scale to stand scale, threatening Araucaria forest regeneration.

Austral Ecology, 2008

Masting, the intermittent and synchronous production of large seed crops, may result from either ... more Masting, the intermittent and synchronous production of large seed crops, may result from either of two major processes: resource matching and economy of scale. Components of cone production in Araucaria araucana were partitioned among populations and trees to ascertain the existence of masting and the processes involved. Cone production data from seven populations were obtained during a 9-year period and seed gathering data were available for an 18-year time series from six sites in an area of more than 7600 km 2 . Araucaria araucana showed environmentally triggered, intermittent, moderately fluctuating, and highly regionally synchronous reproduction.The mean pairwise correlations of cones production among populations and seed gathering sites were 0.89 and 0.74, respectively, suggesting synchrony in reproduction. Among trees we observed a mean correlation of 0.74 with values ranging from 0.66 to 0.81 for the analysed populations. The existence of negative autocorrelation in seed production between year 0 and year -2 at the individual tree level suggests the presence of 'switching' or internal resource allocation, thus discarding the Resource Matching hypothesis. Mean coefficient of variation (CVp) among populations was moderate (0.95) and similar to the modal CVp values reported in the published reports. Mean CVi among individual trees was 1.16, suggesting a large number of equally and synchronously fluctuating trees, rather than a few largely fluctuating individuals. These results suggest that pollination efficiency and/or predator satiation hypotheses could be responsible for the masting cycles in this conifer. Ancillary data about limitation of airborne pollen dispersion and temporal variation in the amount of seeds per cone and about seed predator satiation, also support both proposed mechanisms.

Lanín (Neuquén-Argentina) RESUMEN. Los estudios sobre producción de semillas en especies arbóreas... more Lanín (Neuquén-Argentina) RESUMEN. Los estudios sobre producción de semillas en especies arbóreas son importantes para la ciencia y para el manejo de los bosques nativos. En este trabajo se estudió la producción a largo plazo de conos de araucaria (Araucaria araucana), cuyas semillas son utilizadas como alimento por el ser humano, en poblaciones ubicadas en distinta exposición y altitud, y con diferente composición y estructura forestal. Se contaron conos en siete poblaciones del Parque Nacional Lanín (Neuquén, Argentina) durante 15 años (2000 a 2014), y se estimó la cantidad de conos y semillas por árbol, por hectárea y por población. Los años de máxima producción fueron . La producción media estimada de conos por árbol fue 19 (rango: 1-62); mientras que la de semillas fue 2372 (rango: 61-9287). La mayor variación temporal en la producción de semillas respecto a la de conos se debió a que hubo significativamente más semillas por cono en los años más productivos. El promedio estimado por hectárea fue de 685 conos, 89394 semillas y 273 kilos de semilla. Los bosques puros y densos de araucaria y los mixtos con lenga son, en promedio, al menos 2.5 y 1.5 veces más productivos que el resto de los bosques. El número de conos por árbol varío entre poblaciones y asociado principalmente con la exposición solar. Sin embargo, este efecto difiere según la productividad anual y el patrón observado estaría vinculado con el mecanismo de formación de yemas florales estimulado por la sequía. Estos resultados pueden utilizarse para planificar la conservación de estos bosques en Argentina y Chile frente a la mayor presión en la cosecha de semillas y por la presencia de granívoros introducidos.