Escape behavior in gravid and non-gravid females of Gonatodes albogularis (Squamata: Sphaerodactylidae)

Comportamento de fuga em fêmeas grávidas e não-grávidas de Gonatodes albogularis (Squamata: Sphaerodactylidae). Modelos teóricos de relações predador-presa descrevem balanços entre custos de fuga (energéticos e de outros tipos), efciência do comportamento de fuga e risco de predação. Esses modelos preveem que um animal escapará quando o custo esperado em termos de sucesso reprodutivo devido ao risco de predação quando for igual ao custo de fuga ou quando o sucesso reprodutivo após o encontro for maximizado, dependendo do modelo. Nesse cenário, demonstrou-se que diversas variáveis individuais e ecológicas afetam os padrões de fuga, mas o efeito do status reprodutivo foi estudado em poucas espécies. Nós avaliamos diferenças no comportamento de fuga entre fêmeas grávidas e não-grávidas de Gonatodes albogularis. Os lagartos foram estudados aplicando-se um método de procura livre ao longo de transectos independentes. Para cada fêmea, determinamos o status reprodutivo como grávida ou não-grávida e registramos diversas variáveis relacionadas ao comportamento de fuga. Desenvolvemos uma análise discriminante para verifcar se o estado dos indivíduos afetavam o comportamento de fuga. Nossos resultados mostram que as variáveis distância percorrida na fuga, distância fnal e distância para o refúgio diferem entre fêmeas grávidas e não-grávidas. Essas descobertas sustentam previsões baseadas em risco e custo, mas não sustentam modelos de distância de início de fuga. Tais diferenças poderiam estar relacionadas como um processo conhecido como compensação comportamental, por meio do qual alguns indivíduos (as fêmeas grávidas, no nosso caso) modifcam seu comportamento para compensar risco de predação. Estudos adicionais são necessários para verifcar se a compensação comportamental pode ser explicada em termos de processos adaptativos em G. albogularis.Escape behavior in gravid and non-gravid females of Gonatodes albogularis (Squamata: Sphaerodactylidae). Theoretical models of predator-prey relationships describe tradeoffs between energetic and other costs of escape, effectiveness of escape behavior, and predation risk. These models predict that an animal will fee when the expected ftness cost due to risk of predation becomes equal to the the cost of the escape or post-encounter ftness is maximized, depending on the model. In this framework, several individual and ecological variables have been shown to affect escape patterns, but the effect of reproductive status has been studied in few species. We assess differences in escape behavior between gravid and non-gravid females of Gonatodes albogularis. Lizards were surveyed by applying a free search method along independent transects. For each lizard, we determined reproductive status as gravid or non-gravid and recorded several variables related to escape behavior. We made a discriminant function analysis to see whether the state of individuals affect escape behavior. Our results show that the escape variables distance fed, the fnal distance and the distance to refuge differ between gravid and non-gravid females. These fndings support predictions based on risk and cost, but do not support models of fight initiation distance. Such differences could be related to a physiological process known as behavioral compensation, through which some individuals (gravid females in our case) modify their behavior to offset predation risk. Further studies are needed to see if behavioral compensation can be explained in terms of adaptive processes in G. albogularis

Occupancy and abundance of large macaws in the Beni savannahs, Bolivia

Fil: Berkunsky, Igor. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Cepeda, Rosana E.. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Marinelli, Claudia. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Simoy, María Verónica. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Daniele, Gonzalo. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Kacoliris, Federico Pablo. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Díaz Luque, José A.. Blue-throated Macaw Conservation Project. World Parrot Trust. Trinidad; BoliviaFil: Gandoy, Facundo. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Aramburú, Rosana Mariel. División Zoología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Gilardi, James D.. Blue-throated Macaw Conservation Project. World Parrot Trust. Trinidad; Bolivi

Occupancy and abundance of large macaws in the Beni savannahs, Bolivia

Monitoring of wild populations is central to species conservation and can pose a number of challenges. To identify trends in populations of parrots, monitoring programmes that explicitly take detectability into account are needed. We assessed an occupancy model that explicitly accounted for detectability as a tool for monitoring the large macaws of Bolivia’s Beni savannahs: the blue-throated Ara glaucogularis, blue-and-yellow Ara ararauna and red-andgreen macaws Ara chloropterus. We also evaluated the joint presence of the three macaw species and estimated their abundance in occupied areas. We modelled occupancy and detection for the three macaw species by combining several site and visit covariates and we described their conditional occupancy. Macaws occupied two thirds of the surveyed area and at least two species occurred together in one third of this area. Probability of detection was 0.48–0.86. For each macaw species, occupancy was affected by the abundance of the other two species, the richness of cavity-nesting species, and the distance to the nearest village. We identified key priority areas for the conservation of these macaws. The flexibility of occupancy methods provides an efficient tool for monitoring macaw occupancy at the landscape level, facilitating prediction of the range of macaw species at a large number of sites, with relatively little effort. This technique could be used in other regions in which the monitoring of threatened parrot populations requires innovative approaches.First published on line: 17 July 2014.Facultad de Ciencias Naturales y Muse

A management strategy for the long-term conservation of the Endangered sand-dune lizard <i>Liolaemus multimaculatus</i> in the Pampean coastal dunes of Argentina

The sand-dune lizard Liolaemus multimaculatus is an Endangered species endemic to the Pampean coastal dunes of Argentina. To inform the development of a future Action Plan for this species, we investigated the demography and conservation status of all remaining populations, and we suggest management actions appropriate to local needs. We used population viability analysis to assess extinction risk in three inbreeding scenarios and estimate the minimum viable population and the minimum area requirement. To assess the current status of each local population, we used information related to population size, human pressure and connectivity. The results were then used to set and prioritize conservation management actions at local level. Our models indicated that populations of > 2,400 individuals would be viable in the long term and that inbreeding depression has a strong effect on extinction risk. The southern patches of coastal dune contain the largest populations of sand-dune lizards, and they are also better connected and less threatened. We suggest land protection as the priority management action for populations larger than the minimum viable population, whereas habitat recovery, when possible, should be the priority for patches of coastal dune smaller than the minimum area requirement. Supplementation with a small number of individuals could stabilize unviable populations but should be considered only in certain situations.The long-term conservation of the sand-dune lizard will be feasible only if a conservation action plan is developed and implemented.Facultad de Ciencias Naturales y Muse

Occupancy and abundance of large macaws in the Beni savannahs, Bolivia

Monitoring of wild populations is central to species conservation and can pose a number of challenges. To identify trends in populations of parrots, monitoring programmes that explicitly take detectability into account are needed. We assessed an occupancy model that explicitly accounted for detectability as a tool for monitoring the large macaws of Bolivia’s Beni savannahs: the blue-throated Ara glaucogularis, blue-and-yellow Ara ararauna and red-andgreen macaws Ara chloropterus. We also evaluated the joint presence of the three macaw species and estimated their abundance in occupied areas. We modelled occupancy and detection for the three macaw species by combining several site and visit covariates and we described their conditional occupancy. Macaws occupied two thirds of the surveyed area and at least two species occurred together in one third of this area. Probability of detection was 0.48–0.86. For each macaw species, occupancy was affected by the abundance of the other two species, the richness of cavity-nesting species, and the distance to the nearest village. We identified key priority areas for the conservation of these macaws. The flexibility of occupancy methods provides an efficient tool for monitoring macaw occupancy at the landscape level, facilitating prediction of the range of macaw species at a large number of sites, with relatively little effort. This technique could be used in other regions in which the monitoring of threatened parrot populations requires innovative approaches.First published on line: 17 July 2014.Facultad de Ciencias Naturales y Muse

The rainbow trout is affecting the occupancy of native amphibians in Patagonia

In this work, we assessed the occupancy of two native amphibian species of the Valcheta stream in the Somuncura Plateau, northern Patagonia: the Valcheta frog, Pleurodema somuncurense and the Argentine common toad, Rhinella arenarum. We hypothesized that the occupancy of both amphibian species will be shaped by the presence of trout; we also expected a decline in occupancy assuming that the new predator in the system will affect native amphibian populations. Between December 2014 and March 2015, we conducted surveys in 148 sites along the headwaters of Valcheta stream. We modelled the occupancy by including the presence of trout, the temperature of water and the coverage of rocks and vegetation as site-habitat covariates. Models including trout were among the best ranked for both amphibian species. The presence of trout reduced the occupancy of both species and the magnitude of this reduction was much higher in the Valcheta frog than in the Argentine common toad. Overall, our results are of great relevance for land managers considering that the Valcheta frog is among the only three IUCN Critically Endangered amphibians in Argentina.Facultad de Ciencias Naturales y Muse

Occupancy and abundance of large macaws in the Beni savannahs, Bolivia

Monitoring of wild populations is central to species conservation and can pose a number of challenges. To identify trends in populations of parrots, monitoring programmes that explicitly take detectability into account are needed. We assessed an occupancy model that explicitly accounted for detectability as a tool for monitoring the large macaws of Bolivia’s Beni savannahs: the blue-throated Ara glaucogularis, blue-and-yellow Ara ararauna and red-andgreen macaws Ara chloropterus. We also evaluated the joint presence of the three macaw species and estimated their abundance in occupied areas. We modelled occupancy and detection for the three macaw species by combining several site and visit covariates and we described their conditional occupancy. Macaws occupied two thirds of the surveyed area and at least two species occurred together in one third of this area. Probability of detection was 0.48–0.86. For each macaw species, occupancy was affected by the abundance of the other two species, the richness of cavity-nesting species, and the distance to the nearest village. We identified key priority areas for the conservation of these macaws. The flexibility of occupancy methods provides an efficient tool for monitoring macaw occupancy at the landscape level, facilitating prediction of the range of macaw species at a large number of sites, with relatively little effort. This technique could be used in other regions in which the monitoring of threatened parrot populations requires innovative approaches.First published on line: 17 July 2014.Facultad de Ciencias Naturales y Muse

A management strategy for the long-term conservation of the Endangered sand-dune lizard <i>Liolaemus multimaculatus</i> in the Pampean coastal dunes of Argentina

The sand-dune lizard Liolaemus multimaculatus is an Endangered species endemic to the Pampean coastal dunes of Argentina. To inform the development of a future Action Plan for this species, we investigated the demography and conservation status of all remaining populations, and we suggest management actions appropriate to local needs. We used population viability analysis to assess extinction risk in three inbreeding scenarios and estimate the minimum viable population and the minimum area requirement. To assess the current status of each local population, we used information related to population size, human pressure and connectivity. The results were then used to set and prioritize conservation management actions at local level. Our models indicated that populations of > 2,400 individuals would be viable in the long term and that inbreeding depression has a strong effect on extinction risk. The southern patches of coastal dune contain the largest populations of sand-dune lizards, and they are also better connected and less threatened. We suggest land protection as the priority management action for populations larger than the minimum viable population, whereas habitat recovery, when possible, should be the priority for patches of coastal dune smaller than the minimum area requirement. Supplementation with a small number of individuals could stabilize unviable populations but should be considered only in certain situations.The long-term conservation of the sand-dune lizard will be feasible only if a conservation action plan is developed and implemented.Facultad de Ciencias Naturales y Muse

An individual energy balance model for greater rhea (Rhea americana) and its implication on recruitment

En este trabajo se plantearon modelos individuales del balance energético del ñandú (Rhea americana) para analizar su efecto en el reclutamiento poblacional. El modelo individual se basó en un sistema de ecuaciones que calcula diariamente el peso corporal del individuo en función de su tasa de ingesta y del costo energético de la actividad desarrollada. La tasa de ingesta se estimó a partir de resultados de ensayos en cautiverio. El costo energético diario se estimó a partir de patrones de comportamiento observados en animales silvestres, teniendo en cuenta género y factores que influyen en el comportamiento (e.g. fotoperíodo, período del año). Concatenando los resultados del modelo diario, se obtuvo la dinámica del peso a lo largo del período deseado. Una vez calibrado el modelo, se analizó la factibilidad de diferentes estrategias reproductivas para ambos sexos y se determinó la condición física (peso) que un individuo debe alcanzar para reproducirse exitosamente. Los resultados mostraron que existen pocas restricciones para que una hembra pueda reproducirse pero, en cambio, los machos dependen fuertemente de su estado nutricional para reproducirse exitosamente cada año. Los resultados obtenidos fueron contrastados con observaciones a campo que confirman el bajo éxito reproductivo en la población, a pesar de poseer esta especie un sistema de apareamiento altamente promiscuo. Adicionalmente, se estimó el impacto de poblaciones silvestres en las actividades agropecuarias de la región pampeana bonaerense.We proposed an individual based model of energy budgets of ñandú (Rhea americana) for analyzing its effect on the population recruitment. The individual model was based on a system of equations calculating the weight of an individual as a function of its ingestion rate and energetic cost of its activity pattern with daily step. The ingestion rate was calculated from field experiments. Daily energetic cost was estimated from observed activity patterns at the field, taking into account gender and factors that influence behavior (e.g., photoperiod, season). Concatenating daily model output, the weight dynamics over any period can be obtained. Once the model is calibrated, different reproductive strategies for each gender were analyzed and the minimal body weight that an individual needs to achieve for ensuring reproductive success was determined. Females exhibit low nutritional requirements to produce eggs, but reproductive success of males depends strongly on the body weight. Results obtained were compared to observations made during population censuses Additionally, the impact of wild populations on agricultural activities is assessed using the model.Fil:Simoy, María Verónica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Los medios locales como una herramienta de monitoreo pasivo de mosquitos: el caso del mosquito de inundación Aedes albifasciatus en Tandil

El mosquito Aedes albifasciatus registra picos de abundancia luego de las lluvias debido a que sus estados inmaduros se desarrollan en charcos temporarios. Las quejas asociadas de los vecinos son canalizadas en medios gráficos locales. Nuestro objetivo fue estimar la curva de tiempo de desarrollo huevo-adulto de esta especie en Tandil y validarla con datos retrospectivos de picos de abundancia obtenidos en registros periodísticos locales. A partir de datos de tiempo de desarrollo del mosquito en función de la temperatura en localidades de otras latitudes se ajustó una función para Tandil. Utilizando dicha función y bases de datos de temperatura, precipitación y artículos periodísticos locales se identificó retrospectivamente los eventos de lluvia que desencadenaron los picos, validando los tiempos de desarrollo estimados. El algoritmo desarrollado puede ser de utilidad en otras localidades donde no se dispongan datos de campo.Fil: Gallego, Alejandra. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto Multidisciplinario de Ecosistemas y Desarrollo Sustentable; ArgentinaFil: Simoy, Verónica. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto Multidisciplinario de Ecosistemas y Desarrollo Sustentable; ArgentinaFil: Vezzani, Dario. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto Multidisciplinario de Ecosistemas y Desarrollo Sustentable; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaX Congreso de Ecología y Manejo de Ecosistemas Acuáticos PampeanosAzulArgentinaUniversidad Nacional del Centro de la Provincia de Buenos Aires Facultad de Ciencias Exactas; Instituto de Hidrología de Llanuras "Dr. Eduardo J. Usunoff"Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentabl