USING CALLING ACTIVITY TO PREDICT CALLING ACTIVITY: A CASE STUDY WITH THE ENDANGERED HOUSTON TOAD (BUFO [ANAXYRUS] HOUSTONENSIS)

Understanding anuran calling activity patterns is important for maximizing efficiency and value of call survey data collection and analyses. Previous studies have primarily focused on identifying and quantifying abiotic variables that influence anuran calling activity, and investigating relationships between calling activity and population estimates. In this study we investigated the use of a predictor pond approach to guide call survey effort. In this approach, calling activity at a subset of breeding sites (e.g., ponds) is used as a predictor of calling activity at additional breeding sites, with the goal being to minimize sampling effort while simultaneously maximizing sampling efficiency. We explored the efficiency of this approach using call survey data collected on the endangered Houston Toad (Bufo [Anaxyrus] houstonensis) at 15 known breeding ponds over 9 survey years. We found that if calling activity at 3 predictor ponds was used to decide if additional call surveys would occur at the remaining 12 ponds, we would have hypothetically correctly assumed calling activity was not occurring at non-predictor ponds on 92.1% of survey nights, and we would have hypothetically detected 93.9% of the total number of detected individuals over the 9 survey years. We found the predictor pond approach performed well in our case study, and believe it could be a valuable tool for many anuran monitoring programs

Ecología y comportamiento reproductivo de Eleutherodactylus aureolineatus (Anura, Brachycephalidae) del dosel de la cuenca del Amazonas Superior, Ecuador

Exploration and investigation of the anuran fauna in the canopies of the Upper Amazon Basin has led to the recent discoveries of new species of the genus Eleutherodactylus utilizing the microhabitat within bromeliads. Detailed information on the ecology and natural history of these communities are scarce due, in part, to the difficulty of accessing their habitat. New sampling methods for rainforest canopies have allowed for the collection and observation of the herpetofauna utilizing this habitat. Sexual size dimorphism in Eleutherodactylus aureolineatus, confirms placement in the E. unistrigatus species group and E. lacrimosus assemblage. The described microhabitat, vocalization characteristics, reproductive behavior and egg deposition of E. aureolineatus provides significant ecological background on this poorly documented group of frogs and their important "wetlands in the sky". The data and observations herein contribute to the overall understanding of the characters and ecological factors which define the E. lacrimosus assemblage.La exploración y la investigación de la fauna de anuros en el estrato del dosel de la cuenca del Amazonas Superior ha llevado a descubrimientos recientes de nuevas especies del genero Eleutherodactylus que utilizan el interior de las bromelidas como micro-hábitat. La información detallada en la ecología y la historia natural de estas comunidades es escasa debido en parte a la dificultad de acceso de su hábitat. Nuevos métodos de muestreo para doseles de selvas pluviales han tomado en cuenta la colecta y la observación de la herpetofauna que utiliza este hábitat. El dimorfismo sexual de tamaño en Eleutherodactylus aureolineatus confirma su posición dentro del grupo de especies de E. unistrigatus y la colección de E. lacrimosus. La descripción del micro-hábitat, características de vocalización, comportamiento reproductivo y el sitio de deposición de huevo de E. aureolineatus provee antecedentes ecológicos importantes para este grupo de ranas pobremente documentadas y sus importantes "pantanos en el cielo". Los datos y las observaciones que aquí se presentan, contribuyen a la comprensión general de los caracteres y los factores ecológicos que definen la colección de E. lacrimosus

A new species of the Eleutherodactylus lacrimosus assemblage (Anura, Brachycephalidae) from the lowland rainforest canopy of Yasuni National Park, Amazonian Ecuador

A new species of Eleutherodactylus from the lowland rainforest canopy in northeastern Amazonian Ecuador is described. It is placed in the Eleutherodactylus lacrimosus assemblage of the greater unistrigatus group. It is most similar to the sympatric species Eleutherodactylus lacrimosus, but differs by the lack of a papilla at the tip of the snout, tubercles on upper eyelids, tubercles on dorsum, dorsal markings, and larger body size, and the presence of lateral fringes on the fingers and a tarsal fold. The new species inhabits tank bromeliads in the upper strata of the rainforest canopy at heights of 23.5-38.0 m. The effects of implementation of canopy surveys on biological diversity are briefly discussed

Redução do forrageio do iguana-negro-de-cauda-espinhosa, Ctenosaura similis (Sauria: Iguanidae), na presença de estímulos do predador

The presence of a predator may have direct and indirect effects on the behavior of the prey. Although altered behavior may help prey avoid predators, it also can have a potential impact on critical activities such as foraging. Predator-prey interactions are routinely studied in laboratory-based experiments owing to the perceived difficulties of conducting such experiments in natural settings. We conducted an experimental study under field conditions in Palo Verde National Park in northwestern Costa Rica to assess behavioral responses of Black Spiny-tailed Iguanas (Ctenosaura similis) to the presence of predators and predator cues. Free-roaming iguanas were offered mango in designated areas in the presence of a predator (Boa constrictor), a predator cue (B. constrictor feces), and a control (no predator or predator cue). Results indicate that iguanas reduced their foraging efforts in the presence of both a predator and its cue.A presença de um predador pode exercer efeitos diretos e indiretos sobre o comportamento da presa. Embora a alteração do comportamento possa ajudar a presa a evitar predadores, pode também ter um impacto potencial sobre atividades críticas, como o forrageio. As interações predador-presa são comumente estudadas em experimentos de laboratório devido às dificuldades em conduzir experimentos sob condições naturais. Conduzimos um estudo experimental em campo no Parque Nacional Palo Verde, no noroeste da Costa Rica, para avaliar as respostas dos iguanas-negros-de-cauda-espinhosa (Ctenosaura similis) à presença de predadores e de seus estímulos. Oferecemos manga a iguanas livres em áreas pré-estabelecidas na presença de um predador (Boa constrictor), de um estímulo do predador (fezes de B. constrictor) e em uma áreacontrole (sem predador ou estímulo). Os resultados indicam que os iguanas reduziram seus esforços de forrageio tanto na presença do predador como de seu estímulo

Volumetric rheology of polymers

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Encontro casual na região central do Texas fornece informações sobre a ecologia da estivação de Siren nettingi (Caudata: Sirenidae)

Siren spp. costumam ser vertebrados dominantes nas áreas úmidas que ocupam e são conhecidas por estivar quando essas áreas úmidas secam. Considerações práticas limitam as observações in situ de indivíduos em estivação. Em 12 de outubro de 2021, descobrimos por acaso um agregado em estivação de Siren nettingi no condado de Bastrop, Texas, Estados Unidos. Essas salamandras foram escavadas em solo compacto e rochoso adjacente a uma estrada de caliche, em profundidades que variavam entre ~0,2 e 1,5 m. A vegetação dominante nesse local incluía Ulmus crassifolia, Persicaria sp. e várias espécies de gramíneas. Recuperamos 140 indivíduos, dos quais sete foram resgatados e 133 foram capturados vivos. Medimos 115 deles quanto ao comprimento rostro-cloacal (SVL) e observamos que o agregado era dominado por jovens. Estimamos uma densidade de estivação de 2,33 indivíduos/m2 que é comparável às densidades estimadas para populações sem estivação. No entanto, como não houve monitoramento para esse estudo, provavelmente tenha ocorrido um evento de mortalidade em massa. Portanto, sugerimos que a construção de estradas no habitat preferido seja considerada uma ameaça às populações dessas salamandras.Siren spp. are often dominant vertebrates in the wetlands they occupy and are known to estivate when such wetlands dry up. Practical considerationslimit in-situ observations of estivating individuals. On 12 October 2021, we incidentally discovered an estivating aggregate of Siren nettingi in Bastrop County, Texas, USA. These salamanders were excavated from compact, rocky soil adjacent to a caliche road, at depths that ranged between ~0.2 to 1.5 m. The dominant vegetation at this site included Ulmus crassifolia, Persicaria sp., and various grass species. We recovered 140 individuals of which seven were salvaged and 133 were captured live. We measured 115 of these for snout–vent length (SVL) and observed the aggregate was predominated by juveniles. We estimated an estivation density of 2.33 sirens/m2 that is comparable to densities estimated for non-estivating populations. However, in-lieu of monitoring that was in place for this study, we expect a mass mortality event would have likely occurred. We therefore suggest that roadway construction in preferred habitat be considered as a threat to siren populations