CEAZA
Male morphotypes in the Andean river shrimp Cryphiops caementarius (Decapoda: Caridea): morphology, coloration and injuries.
Rojas, R., Morales, M., Rivadeneira, M., & Thiel, M.
In many species, different male morphotypes usually employ different tactics to access resources. Males with highly developed weapons are expected to fight and possibly incur higher levels of injury than males with less developed weapons, which usually avoid agonistic encounters. Discrete male morphotypes, where some males are very large and feature powerful chelae, have been reported for several large shrimp species, where males show a lobster-like monopolization of resources. During competitive interactions, these large males fight more vigorously than small males and, consequently, it is expected that they accumulate more injuries. Herein, we identified different morphotypes in the river shrimp Cryphiops caementarius, and we compared the percentage of body damage between large and small shrimps. We measured 26 morphometric data and 6 intensities of color on the chelipeds. Multivariate analysis based on a combination of morphometric and color data confirmed that there are two morphotypes. The ‘dominant’ morph is characterized by stout teeth on the cutting edges and by dark blue color on the external surface of the major cheliped. The two morphotypes can be distinguished based on the differences in the allometric relationships between several morphologic traits and carapace length. Males from the large morphotype had a higher percentage of injuries on their chelipeds than other males. These results suggest that males from the large morphotype are dominant and compete aggressively for access to resources, a hypothesis to be tested in future, behavioral studies.
Año: 2012
Palabras claves: alternative reproductive tactics; male morphotypes; injury; weapon; large chela; shrimp
Referencia APA: Rojas, R., Morales, M., Rivadeneira, M., & Thiel, M. (2012). Male morphotypes in the Andean river shrimp Cryphiops caementarius (Decapoda: Caridea): morphology, coloration and injuries. J Zool, 288(1), 21-32.
Comparación del crecimiento de Argopecten purpuratus entre cohortes obtenidas de captacion de larvas en ambiente natural y de hatchery.
Perez, E., Azocar, C., Araya, A., Astudillo, O., & Ramos, M.
En Chile los cultivos del ostión del norte Argopecten purpuratus han sido desarrollados intensivamente a partir de la captación de semillas en ambiente natural y desde principios de 1980 con semillas obtenidas en hatchery. Para aportar información sobre el desempeño de semillas de ostión del norte en este estudio se comparó, mediante ANCOVA, el crecimiento en longitud entre cohortes producidas a partir de semillas de ambiente natural y de hatchery en Tongoy, Chile. Se evaluó la consistencia de esta comparación en distintos años y estaciones, comparándose parejas de cohortes producidas simultáneamente en los años 2003 (primavera), 2005 (invierno) y 2006 (verano). El análisis estadístico mostró que existen diferencias estadísticas significativas entre cohortes obtenidas en ambiente natural y aquellas obtenidas en hatchery. La prueba de Tukey evidenció diferencias significativas entre CN2003 y CH2003 como también entre CN2005 y CH2005, pero no así entre CN2006 y CH2006. Estas diferencias indican que las cohortes de semillas de ambiente natural crecieron más rápido que las de hatchery. La comparación interanual evidenció diferencias estadísticas significativas. Estos resultados son discutidos a la luz de dos factores: la temperatura de cultivo y la heterocigocidad de la población de cultivo.
Año: 2012
Palabras claves: ostión, semillas, ambiente natural, hatchery, crecimiento, norte de Chile.
Referencia APA: Perez, E., Azocar, C., Araya, A., Astudillo, O., & Ramos, M. (2012). Comparación del crecimiento de Argopecten purpuratus entre cohortes obtenidas de captacion de larvas en ambiente natural y de hatchery. Latin American Journal Of Aquatic Research, 40(4), 1026-1038.
Respuestas antioxidantes en dos ecotipos de Colobanthus quitensis (Caryophyllaceae) expuestos a alta radiación UV-B y baja temperatura.
Navarrete-Gallegos, A., Bravo, L., Molina-Montenegro, M., & Corcuera, L.
Colobanthus quitensis (Kunth) Bartl. (Caryophyllaceae) está distribuida desde México hasta la Antártida Marítima formando poblaciones adaptadas a distintas condiciones microambientales a lo largo de su distribución. La Antártica Marítima se caracteriza por una estación de crecimiento más fría y breve, con crecientes niveles de radiación UV-B. Los Andes de Chile Central, en cambio, tienen oscilaciones térmicas más amplias y una elevada tasa de radiación UV-B. El objetivo de este estudio es conocer las estrategias y mecanismos antioxidantes adoptadas por los ecotipos Antártico y Andino para tolerar los efectos dañinos de la radiación UV-B y el frío bajo condiciones controladas de laboratorio. Postulamos que los individuos de C. quitensis provenientes de la cordillera de Los Andes de Chile Central, donde los niveles de radiación UV-B son mayores que en la Antártica, tendrían un conjunto de mecanismos antioxidantes más eficaces para contrarrestar los efectos del UV-B y sufrirían menos daño que el ecotipo Antártico. Plantas cultivadas en laboratorio del ecotipo Antártico y Andino fueron sometidas a tres intensidades de radiación UV-B (70, 35 y 3 µW cm-2), a 4 y 15 °C, respectivamente. En cada tratamiento se evaluaron las respuestas de la actividad antioxidante total (TAS), actividad de la enzima superóxido dismutasa (SOD) y características anatómicas foliares con un posible rol protector frente a UV-B. Finalmente, se evaluaron los efectos dañinos del UV-B, como son: acumulación de malonaldialdehido (MDA), eficiencia fotoquímica máxima del PSII y fotoinactivación. Ambos ecotipos mostraron reducción de área foliar y engrosamiento del parénquima. El ecotipo andino presentó mayores niveles de TAS con radiación UV-B media y alta. La actividad SOD máxima se midió en el ecotipo andino, encontrándose un aumento de hasta ocho veces el nivel basal a las cuatro horas de irradiación. El ecotipo antártico expuesto a UV-B y frío presentó un mayor daño a membranas (MDA), al igual que un mayor grado de fotoinactivación. Adicionalmente, se detectó la acumulación de una nueva isoforma Cu-Zn/SOD, insensible a H2O2, en plantas tratadas con UV-B. En conclusión, el ecotipo andino presenta una respuesta antioxidante más efectiva contra el UV-B que el ecotipo antártico.
Año: 2012
Palabras claves: Antártica, antioxidantes, daño oxidativo, UV-B.
Referencia APA: Navarrete-Gallegos, A., Bravo, L., Molina-Montenegro, M., & Corcuera, L. (2012). Respuestas antioxidantes en dos ecotipos de Colobanthus quitensis (Caryophyllaceae) expuestos a alta radiación UV-B y baja temperatura. Rev. Chil. Hist. Nat., 85(4), 419-433.
Rodent middens reveal episodic, long-distance plant colonizations across the hyperarid Atacama Desert over the last 34,000 years.
Díaz, F., Latorre, C., Maldonado, A., Quade, J., & Betancourt, J.
Five middens span the last glacial period (34–21 ka) and three middens are from the last glacial–interglacial transition (19–11 ka). The remaining 13 middens span the last 7000 years. Coastal hyperarid sites exhibit low taxonomic richness in middens at 19.3, 1.1, 1.0, 0.9, 0.5 ka and a modern sample. Middens are also dominated by the same plants that occur today. In contrast, middens dated to 28.1, 21.3, 17.3, 3.7 and 0.5 ka contain more species, including Andean extralocals. Precordillera middens (c. 2700 m) show a prominent increase in plant macrofossil richness, along with the appearance of Andean extralocals and sedges at 34.5 and 18.9 ka. Six younger middens dated to 6.1–0.1 ka are similar to the modern local vegetation.
Año: 2012
Palabras claves: Abrocoma;aridland palaeoecology;Atacama Desert;fog oases;hyperarid environments;late Quaternary;Lomas vegetation;Phyllotis;rodent middens
Referencia APA: Díaz, F., Latorre, C., Maldonado, A., Quade, J., & Betancourt, J. (2012). Rodent middens reveal episodic, long-distance plant colonizations across the hyperarid Atacama Desert over the last 34,000 years. Journal Of Biogeography, 39(3), 510-525.
The role of spatial processes and environmental determinants in microgeographic shell variation of the freshwater snail Chilina dombeyana (Bruguière, 1789).
Bertin, A., Ruíz, V., Figueroa, R., & Gouin, N.
Wildlife data often show spatial organization, demonstrating positive correlations either as a result of processes occurring over the landscape or due to the influence of spatially structured environmental variables. It is, thus, essential to consider non-random spatial structure when evaluating the underlying causes of biological variation. In this study, we analyzed the population structure of Chilina dombeyana shell morphology of 14 populations that are close geographically and belong to the same hydrographic basin. We utilized a variation partitioning approach to evaluate the importance of spatial processes, such as migration, acting over the landscape, and environmental characteristics, including habitat and hydrologic characteristics, and the occurrence of aquatic predators in promoting between population variation. Our results demonstrate spatially structured variation in C. dombeyana shell morphology, with populations living near each other having more similar shell sizes than populations living farther apart. The shell size variation partition indicated that both spatially structured environmental factors and genetic relationships resulting from migration or shared common ancestry may explain this pattern. Shell shape variation, in contrast, was found to be essentially under the influence of non-spatially structured environmental factors, with habitat and water characteristics accounting for about half of the total variation among populations. The large proportion of the variation in shell size that is spatially structured demonstrates that spatial structure on morphological traits might be strong and highlights the need to consider such phenomenon in intraspecific studies of phenotypic evolution.
Año: 2012
Palabras claves: Shape, Size, Environmental factors, Spatial structure, Gastropod, Variation partition, Lotic environment
Referencia APA: Bertin, A., Ruíz, V., Figueroa, R., & Gouin, N. (2012). The role of spatial processes and environmental determinants in microgeographic shell variation of the freshwater snail Chilina dombeyana (Bruguière, 1789). Naturwissenschaften, 99(3), 225-232
Latin American plant sciences: from early naturalists to modern science.
Stoll, A. & Squeo, F.
Editorial
Año: 2012
Palabras claves:
Referencia APA: Stoll, A. & Squeo, F. (2012). Latin American plant sciences: from early naturalists to modern science. Plant Ecology & Diversity, 5(2), 147-151.
Climatic trends and impact of climate change on agriculture in an arid Andean valley.
Fiebig-Wittmaack, M., Astudillo, O., Wheaton, E., Wittrock, V., Perez, C., & Ibacache, A.
Little is known about climate change and its impacts for the arid coastal and mountainous regions in northern Chile. The Elqui river basin, part of the Norte Chico of Chile between 27ºS and 33ºS latitude, is located south of the hyper-arid Atacama desert. Despite water scarcity, agricultural development in this region has been enhanced by agronomic practices and the marketing of valuable products. This paper characterizes the actual climate conditions and presents an overview and analyses of past climate variability, and future possible climate trends, emphasizing those relevant to agriculture. Precipitation shows an important decrease during the first decades of the past century. Runoff shows decreasing trends for the first half of the past century and increases for 1960 to 1985. Drought appears to be increasing. Statistical downscaling was accomplished using the Long Ashton Research Station Weather Generator. Both future periods of 2011 to 2030 and 2046–65 showed trends to higher minimum and maximum temperature. The number of hot days (maximum temperature greater than or equal to 30°C) has a strong increasing trend during October to April. Even though the downscaled results for precipitation do not show trends, the continuation of the present trend of low amounts is a concern. We discuss some implications of climatic changes for agriculture and we emphasize the importance of adaptation, especially to deal with water scarcity.
Año: 2012
Palabras claves:
Referencia APA: Fiebig-Wittmaack, M., Astudillo, O., Wheaton, E., Wittrock, V., Perez, C., & Ibacache, A. (2012). Climatic trends and impact of climate change on agriculture in an arid Andean valley. Climatic Change, 111(3-4), 819-833
Plant invasions research in Latin America: fast track to a more focused agenda.
Gardener, M., Bustamante, R., Herrera, I., Durigan, G., Pivello, V., & Moro, M., Stoll, A., et al.
While many developed countries have invested heavily in research on plant invasions over the last 50 years, the immense region of Latin America has made little progress. Recognising this, a group of scientists working on plant invasions in Latin America met in Chile in late 2010 to develop a research agenda for the region based on lessons learned elsewhere. Our three main findings are as follows. (1) Globalisation is inevitable, but the resultant plant introductions can be slowed or prevented by effective quarantine and early intervention. Development of spatially explicit inventories, research on the invasion process and weed risk assessments can help prioritise and streamline action. (2) Eradication has limited application for plants and control is expensive and requires strict prioritisation and careful planning and evaluation. (3) Accepting the concept of novel ecosystems, new combinations of native and introduced species that no longer depend on human intervention, may help optimise invasive species management. Our vision of novel ecosystem management is through actions that: (a) maintain as much native biodiversity and ecosystem functionality as possible, (b) minimise management intervention to invasives with known impact, and (c) maximise the area of intervention. We propose the creation of a Latin American Invasive Plants Network to help focus the new research agenda for member countries. The network would coordinate research and training and establish funding priorities, develop and strengthen tools to share knowledge, and raise awareness at the community, governmental and intergovernmental levels about the social, economic and environmental costs of plant invasions.
Año: 2012
Palabras claves: control, eradication, globalisation, inventories, novel ecosystems, plant invasions, quarantine, Weed Risk Assessment,
Referencia APA: Gardener, M., Bustamante, R., Herrera, I., Durigan, G., Pivello, V., & Moro, M., Stoll, A., et al. (2012). Plant invasions research in Latin America: fast track to a more focused agenda. Plant Ecology & Diversity, 5(2), 225-232.
Evaluation of sediment trace metal records as paleoproductivity and paleoxygenation proxies in the upwelling center off Concepción, Chile (36°S)
Muñoz, P., Dezileau, L., Lange, C., Cardenas, L., Sellanes, J., Salamanca, M., & Maldonado, A.
This study analyzes the records of several trace metals sensitive to redox conditions in continental shelf sediments off Concepción, Chile (36°S). The continental margin off Concepción (36°S; 73°W) lies beneath an important upwelling center characterized by high primary production rates and, consequently, high fluxes of organic matter. In spring and summer, this material settles to the seafloor where it decays, producing periods of very low oxygen content in bottom waters (<1 mL L−1). In addition, an oxygen minimum zone develops at ∼100–400 m water depth, where dissolved oxygen levels are <0.5 mL L−1. This situation changes during strong El Niño events, when dissolved oxygen at the bottom increases drastically (>1 mL L−1).
Año: 2012
Palabras claves:
Referencia APA: Muñoz, P., Dezileau, L., Lange, C., Cardenas, L., Sellanes, J., Salamanca, M., & Maldonado, A. (2012). Evaluation of sediment trace metal records as paleoproductivity and paleoxygenation proxies in the upwelling center off Concepción, Chile (36°S). Progress In Oceanography, 92-95, 66-80.
A three-year mark-recapture study in a remnant population of Crocodylus acutus Cuvier in Portete Bay (Guajira, Colombia).
Espinosa, M., Bertin, A., Gómez, J., Mejía, F., Guerra, M., & Baez, L., Gouin, N., Patiño, E.
El Cocodrilo Americano Crocodylus acutus, ha experimentado importantes declines poblacionales a lo amplio de su distribución debido a la persecución humana, la sobreexplotación y la pérdida de hábitat. C. acutus permanece en peligro crítico en algunos países tales como Colombia donde la ausencia de estudios detallados sobre su ecología y distribución constituyen una de las barreras principales para el desarrollo de efectivas estrategias de conservación. Durante tres años desarrollamos un estudio de captura-recaptura para investigar el estatus demográfico de C. acutus e identificar las variables medioambientales más influyentes en su distribución en Bahía Portete (Colombia). Nosotros estimamos que la población de cocodrilos es relativamente pequeña (< 140 animales), incluye muy pocos adultos y demuestra un fuerte déficit de hembras en la clase juvenil. La humedad relativa y la temperatura promedio del aire estuvieron positivamente correlacionadas con el número de avistamientos de cocodrilos. Por el contrario, la salinidad promedio del agua se encontró relacionada con la baja probabilidad de observación, presumiblemente debido a la preferencia de los juveniles por áreas de baja salinidad. Nuestros resultados sugieren que la población de C. acutus en Bahía Portete está en riesgo y puede requerir la intervención humana para asegurar su persistencia.
Año: 2012
Palabras claves: Captura-recaptura, cocodrilo, variables medioambientales, manglar
Referencia APA: Espinosa, M., Bertin, A., Gómez, J., Mejía, F., Guerra, M., & Baez, L., Gouin, N., Patiño, E. (2012). A three-year mark-recapture study in a remnant population of Crocodylus acutus Cuvier in Portete Bay (Guajira, Colombia). Gayana (Concepción), 76(1), 52-58.
Annual brood number and breeding periodicity of squat lobsters (Decapoda: Anomura: Galatheidae) from the continental shelf of the SE Pacific—Implications for fisheries management.
Thiel, M., Espinoza-Fuenzalida, N., Acuña, E., & Rivadeneira, M.
The reproductive potential of a population depends on the number of broods that individuals produce during the annual reproductive season. Determining the annual brood number is especially relevant for species that are actively fished. Herein we combined different approaches to estimate the annual brood number of two commercially exploited species of squat lobsters from the Chilean continental shelf and upper slope, Cervimunida johni and Pleuroncodes monodon. Long-term maintenance in the laboratory revealed that most females (>70%) produced 3 or more broods during the annual reproductive season. Incubation of individual broods required about 40 days, which would allow for 3 subsequent broods during the main reproductive period (June–September). The dynamics of brood release of ovigerous females that were collected from the field at approximately monthly intervals supported the estimate of 3–4 annual broods for adult females. Furthermore, these latter data also indicated a high degree of breeding synchrony among reproductive females. It is suggested that the production of successive broods might be an adaption to the variable oceanographic conditions during the reproductive period, ensuring that at least one larval cohort finds favorable conditions for development and settlement. Based on these results it is recommended that fishing effort is reduced during the main reproductive period of the two squat lobsters.
Año: 2012
Palabras claves: Squat lobsters; Trawl fishery; Fisheries management; Reproduction; Annual brood number; Mating synchrony
Referencia APA: Thiel, M., Espinoza-Fuenzalida, N., Acuña, E., & Rivadeneira, M. (2012). Annual brood number and breeding periodicity of squat lobsters (Decapoda: Anomura: Galatheidae) from the continental shelf of the SE Pacific—Implications for fisheries management. Fisheries Research, 129-130, 28-37.
Major hydrological regime change along the semiarid western coast of South America during the early Holocene.
Ortega, C., Vargas, G., Rutllant, J., Jackson, D., & Méndez, C.
Water availability in the semiarid western coast of Chile (30–32°S) is conditioned by high interannual precipitation variability, reflecting the transition between arid subtropical and moist mid-latitude climates in the Southeastern Pacific Ocean. A paleoclimate reconstruction based on the latest Pleistocene–Holocene geological record from the Quebrada Santa Julia archeological site in Chile (31°50′S) and on modern meteorological mechanisms producing alluvial episodes in this region indicates a major change in the rainfall regime shortly after 8600 cal yr BP. This, together with other paleoclimate proxies along the west coast of South America (34°–14°S), suggests La Niña-like conditions 13,000–8600 cal yr BP. Based on sedimentological and geomorphologic evidence, we hypothesized that the absence of heavy rainfall events in northern Chile and the new hydrological regime that prevailed ca. 8600–5700 cal yr BP in north-central Chile resulted from an increase in the large-scale westerly flow over central Chile, as expected in near-neutral ENSO conditions. This atmospheric circulation anomaly is compatible with an equatorward shift of the influence of the Southeast Pacific Subtropical Anticyclone relative to the early Holocene, prior to the onset of modern ENSO variability.
Año: 2012
Palabras claves: Paleoclimate; Early Holocene; Alluvial flow; Heavy rainfall; Coastal fog; El Niño Southern Oscillation (ENSO); Western South America; Paleohydrology; Pacific Ocean.
Referencia APA: Ortega, C., Vargas, G., Rutllant, J., Jackson, D., & Méndez, C. (2012). Major hydrological regime change along the semiarid western coast of South America during the early Holocene. Quaternary Research, 78(3), 513-527.