The Response of Two Liolaemus Lizard Species to Ash from Fire and Volcanism
Fires and volcanic eruptions produce ash that may negatively affect survivors of the disturbances themselves. Therefore, animals are expected to avoid areas covered by ash when possible. We tested this prediction by determining the substrate selection, ash vs. soil, in two insectivorous Liolaemus lizard species. We exposed each species to the type of ash it is most likely to encounter in its habitat: fire ash for Liolaemus lemniscatus and volcanic ash for Liolaemus pictus. We also determined the ability of these species to track insect scents in ash, as the effectiveness of scent tracking, and hence the ability to find food, may be reduced in ash. Contrary to our expectations, both species explored ash more than soil, and they were able to detect insect scents in ash. We concluded that at least shortly (e.g., days) after a disturbance involving ash production, surviving lizards may not avoid ash that may have negative impact on their health. Lizards would be able to find insects in substrates covered by ash by tracking their scents, however, suggesting that starvation may not necessarily be an immediate cause of mortality after a fire or a volcanic eruption. Los incendios y las erupciones volcánicas producen cenizas que pueden afectar negativamente a los sobrevivientes de estas perturbaciones. Es por lo tanto esperable que los animales intenten evitar zonas cubiertas por cenizas, cuando sea posible. Nosotras probamos esta predicción determinando la selección de sustrato, ceniza vs. tierra, en dos especies de lagartijas insectívoras de Liolaemus. Expusimos a cada especie al tipo de ceniza más probable de encontrar en su hábitat; cenizas de fuego para Liolaemus lemniscatus y volcánica para Liolaemus pictus. También determinamos la habilidad de estas especies de rastrear esencias de insectos, dado que la efectividad del rastreo de esencias, y por lo tanto la habilidad de encontrar alimento, podría reducirse en las cenizas. Contrario a nuestras expectativas, ambas especies exploraron más la ceniza que la tierra, y fueron capaces de detectar esencias de insectos en la ceniza. Concluimos que al menos en un período relativamente corto (e.g. días) después de una perturbación que involucre la producción de ceniza, los lagartos sobrevivientes no evitarían las cenizas, lo que podría afectar negativamente su salud. Sin embargo, los lagartos serían capaces de encontrar insectos en sustratos cubiertos de cenizas rastreando sus esencias, sugiriendo que la hambruna no sería necesariamente una causa inmediata de mortalidad después de un incendio o de una erupción volcánica.Abstract
Resumen
Geographic locations in Chile where soil, ash, and lizards (Liolaemus lemniscatus and Liolaemus pictus) were collected.
Mean (± SE) values of three behaviors recorded in Liolaemus lemniscatus in the two sections of the two experimental conditions, substrate discrimination (ash vs. soil; left panel. Sample size (N = 22) and prey–scent discrimination (with vs. without prey scents; right panel. N = 15). A and D: Number of tongue flicks, B and E: Time moving and C and F: Total time of permanence in each section. Each graph gives the result of a t-test and associated P-value. Data for statistical analyses in A and E were square-root transformed, whereas data of B were log10 transformed. We present, however, the untransformed data of those variables. Photo: Marta Mora.
Mean (± SE) values of three behaviors recorded in Liolaemus pictus in the two sections of the two experimental conditions, substrate discrimination (ash vs. soil; left panel. Sample size (N) = 21) and prey-scent discrimination (with vs. without prey scents; right panel. N = 14). A and D: Number of tongue flicks, B and E: Time moving and C and F: Total time of permanence in each section. Each graph gives the result of the t-test and associated P-value. For the analysis, data for B and E were log10 transformed. We present, however, the untransformed data of those variables. Photo: Michael Weymann.
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