Natural selection favors signals that maximize information transfer relative to background noise, reducing signal and/or information degradation. When background interference is unavoidable, multiple signals can arise, sending redundant information to ensure proper communication. Herein, we test the hypotheses that visual signaling in anurans can be an alternative to (H1a) or a reinforcement of (H1b) acoustic signaling when communication occurs in naturally noisier environments. If H1a is correct, we expect that an increase in background noise level will result in a decrease in call rates coupled with in an increase in visual displays. Alternatively, if H1b is correct, we expect an increase in visual displays without reducing call rates. To test these predictions we counted the visual and acoustic responses of male anurans exposed to artificial models constructed to simulate a conspecific male intruder. These counts were correlated with the sound pressure level of the environment where the experiments were conducted. We tested three nocturnal treefrog species, one that reproduces in fast-torrent streams (Bokermannohyla sapiranga) and two that form choruses (Boana albopunctata and B. goiana). The rate of call emission was not influenced by the background noise level. Despite the observed diversity of visual displays (limb lifting, face wiping, toe/finger trembling, upright posture, vocal sac display, head bobbing), only the emission of face wiping displays by males of B. sapiranga was correlated with background noise, but it was reduced with the increase of the background noise level. Thus, we did not find empirical support for our hypotheses, which suggests that these species might be fully adapted to the natural noisy background variation from where they breed.

Selection of breeding habitats represents one of the most effective ways in which anurans can offer advantages for offspring survival. In arid environments tadpoles developing in ephemeral pools face different risks for survival such as pond drying, predation, high levels of salinity, and exposure to high temperatures. Therefore, in these environments adults should actively select ponds with biotic and abiotic attributes that favor tadpole survival. In this work, we evaluate whether two frog species inhabiting halophytic shrublands from Dry Chaco (Pleurodema guayapae and Lepidobatrachus llanensis) select pond attributes for reproduction and whether selection favors the success of tadpoles on reaching metamorphosis. We recorded the use/non-use of ephemeral pools for reproduction in both species and measured five pond attributes to detect selection of breeding sites. Next, we monitored a subset of sites used for reproduction in each species in order to relate metamorphosis success with the same pond attributes. The results showed that L. llanensis selected ponds with particular attributes, while P. guayapae laid its eggs in any available pond, even ponds that dried prior to metamorphosis. Using any pond available in multiple reproductive events together with the remarkably fast development of tadpoles could actually be a strategy to effectively deal with stochasticity in rain frequencies after the formation of ephemeral ponds.

The dates of the onset of spawning migrations of local populations of Pelobates vespertinus (the Pallas spadefoot toad) in the Medveditsa river valley (Russia, Saratov Region) were determined in 2009–2019. It was found that the minimum threshold value of the water temperature in every spawning water body corresponding to the arrival of first individuals of the species to their spawning area was 4.5°C. Moreover, according to the nearest weather station's long-term forecast of air temperature, the average daily water temperature at the spawning site was calculated, equal to the average daily air temperature over 10 d. By analyzing the dynamics of this indicator, the dates of a steady transition of water temperature through its threshold value (4.5°C) were calculated. This date was considered the predicted start date of P. vespertinus spawning migrations. Any deviation of the actual start date of spawning migrations from the predicted one did not exceed 3 d for 11 years. The lead time for predicting the actual start date of migrations is positively related to the water temperature increase rate. During the study period, the lead time of the forecast was 6–18 d (12 d on the average). Our historical reconstruction of the long-term dynamics of the water temperature increase rate from weather archives and the forecast lead time (according to a model describing their relationship) in 1892–2008 showed that these parameters had no significant intra-century trend against the background of global climate warming. Our proposed method for predicting the start date of spawning migrations can be recommended for use in planning any research on P. vespertinus populations, ecosystem processes, and species conservation measures.

The conversion of natural environments into extensive agricultural monocultures is one of the principal drivers of the ongoing decline and extinction of anuran populations. These processes of landscape modification may modify the structure of natural communities in a variety of ways and at a number of different levels. In this case study, we aimed to evaluate the taxonomic and functional composition of leaf-litter anurans in an agricultural landscape in southern Brazil to understand the relationship between the ecological and morphological traits of these vertebrates and the environment. We sampled forest and plantation environments using pitfall traps and described and quantified the ecological and morphological traits of all the individuals collected in these two environments. We used permutational multivariate analyses of variance (perMANOVA) to evaluate the variation in the composition in the anuran assemblage between the forest and the plantation, a principal coordinate analysis (PCoA) to test the relationship between these traits and the environments, and generalized linear mixed models (GLMM) to evaluate possible patterns of differentiation in the morphological traits of the anurans in the different habitats. Our results indicated that no significant variation exists in the taxonomic and functional composition of the forest and plantation environments, and the functional structure varied only in relation to the body length of the specimens. Although this was a small-scale case study, we found that the anurans tended to exploit different environments according to the functional characteristics of their reproductive modes, habits, and life cycles.

Invasive amphibians and reptiles have historically been ignored by governments and science, especially in the Neotropics. There have been few studies related to invasive herpetofauna in Brazil, making information about this group scarce. Our aim was to review the current status of alien amphibians and reptiles with wild populations in Brazil. We compiled knowledge about the history of invasions, biological characteristics of species, and their impacts and current distributions in Brazil. In addition, we discuss management and policy actions that must be implemented for each species, especially for the most harmful ones. We found six amphibian and six reptile invasive species recorded in Brazil, in addition to four reptile species that were considered potential invaders. There are confirmed negative impacts on human health and biodiversity for two amphibians (Aquarana catesbeiana and Rhinella jimi) and two reptiles (Salvator merianae and Trachemys scripta elegans). The main routes of introduction of invasive herpetofauna in Brazil are the pet trade and commercial production. Most invasive species are present in the Atlantic Forest and three are found only in the Fernando de Noronha archipelago. Furthermore, most species have small and dispersed populations that allow monitoring programs for research or even eradication, especially for island populations. Species at more advanced stages of invasion, such as A. catesbeiana and T. scripta elegans, need a national program to control populations and prevent spread. Further ecological studies are important to assess the impacts of invasive herpetofauna on Brazilian biodiversity, as is the straightforward implementation of action plans with the best techniques for the control or eradication of these populations.

Agroecosystems occupy a large portion of the Ecuadorian Chocó; unfortunately, most modern agricultural practices involve the use of agrochemicals that damage local flora and fauna or displace them to remnant forests. The present study evaluates the herpetofauna diversity and community structure of the Ecuadorian Chocó organic and non-organic agroecosystems by performing diurnal monitoring in linear transects in crops of two high-demand products, plantain and passion fruit. The results indicate that community composition changes due to seasonality and agroecosystem types independently. In the dry season, higher diversity was observed in organic crops than non-organic crops, while in the rainy season more species were observed in the organic and non-organic plantain crops than the passionfruit crops. The most abundant species in both seasons was Holcosus septemlineatus, suggesting that it is highly tolerant to disturbance. Further, niche overlap occurs among species found near the ground and in shady areas, since they compete for resources or establish prey–predator interactions. We conclude that several of the studied species can be used as indicators of environmentally favorable agricultural practices.

Los agroecosistemas ocupan una gran parte del terreno que forma el Chocó ecuatoriano; desafortunadamente, las prácticas agrícolas modernas implican el uso de agroquímicos que pueden causar daños en la flora y fauna local o desplazar a las mismas a pequeños remanentes de bosque. El presente estudio evalúa la diversidad de herpetofauna y estructura comunitaria de los agroecosistemas, orgánicos e inorgánicos, del Chocó ecuatoriano, mediante el monitoreo diurno en transectos lineales en cultivos de dos productos de alta demanda, plátano y maracuyá. Los resultados indican que la composición de la comunidad de herpetofauna cambia debido a la estacionalidad y los tipos de agroecosistemas de forma independiente. En la época seca se observó una mayor diversidad en cultivos orgánicos en comparación con los inorgánicos, mientras que en la época de lluvias se observaron más especies en cultivos de plátano orgánico e inorgánico en comparación con el maracuyá. La especie más abundante en ambas estaciones fue Holcosus septemlineatus, lo que significa que es muy tolerante a las perturbaciones. Además, se indica que existe una superposición de nichos de especies que se encuentran cerca del suelo y en espacios sombreados, por lo que compiten por los recursos o establecen interacciones presa-depredador. Se concluyó que varias especies reportadas aquí pueden usarse como indicadores de prácticas agrícolas amigables con el medio ambiente.

Amphibians and reptiles are highly sensitive to environmental changes due to their physiological and biological characteristics. Nevertheless, the effects of landscape changes on amphibians and reptiles are rarely studied. We set out to determine the effect of landscape attributes at two different scales (landscape and patch) on herpetofaunal diversity in the area influenced by the Reserva de la Biosfera Selva el Ocote, a Protected Natural Area in Chiapas, Mexico. We monitored the herpetofauna from January 2018 to March 2019. We used general linear models to determine the effect of landscape composition and configuration at the two scales. Amphibians were affected by attributes at both scales; their diversity was positively affected by more a permeable matrix and heterogeneous sites at the landscape scale, while being negatively affected by larger patches at the patch scale. In contrast, reptiles were only affected at the patch scale; their diversity was positively affected by greater distances of patches from highways and roads and was negatively affected by greater distances between similar patches and from water bodies. The response of amphibians to attributes at both the landscape and patch scales suggests that their diversity could be favored by habitat, microhabitat, and microclimate conditions contributing to their access to vital resources, decreased risk of desiccation, and decreased exposure to predators. In contrast, for reptiles, connectivity and ease of mobility among patches and access to water bodies at the patch scale appear to be the most relevant requirements to preserve species in the area.

Los anfibios y reptiles son muy sensibles a los cambios ambientales debido a sus características biológicas y fisiológicas. A pesar de ello se ha estudiado poco el efecto de los cambios en el paisaje sobre estos grupos. Nos propusimos determinar el efecto de los atributos del paisaje a dos diferentes escalas (paisaje y fragmento) sobre la diversidad herpetofaunística. Este estudio se realizó en Chiapas, México, en la zona de influencia del área natural protegida denominada Reserva de la Biosfera Selva el Ocote. Se monitoreó la herpetofauna entre Enero del 2018 y Marzo del 2019. Para determinar el efecto de la composición y configuración del paisaje a dos diferentes escalas sobre la herpetofauna se utilizaron Modelos Lineales Generalizados (MLG). Los anfibios fueron afectados tanto a escala de paisaje como de fragmento; su diversidad se ve favorecida por una matriz más permeable y por sitios heterogéneos a escala de paisaje, mientras que a escala de fragmento es afectada negativamente por los fragmentos más grandes. Los reptiles fueron afectados únicamente a escala de fragmento; su diversidad fue favorecida por fragmentos a mayores distancias de carreteras y caminos, y fue negativamente afectada por las distancias entre fragmentos del mismo tipo, así como por las distancias a cuerpos de agua. La respuesta de los anfibios a los atributos del paisaje en el área sugiere que a las escalas de paisaje y de fragmento su diversidad puede verse favorecida por condiciones de hábitat, microhábitat y microclimas que contribuyen con acceso a recursos vitales, a un bajo riesgo de deshidratación y menor exposición a depredadores. Por otro lado, para los reptiles la conectividad entre los fragmentos y el acceso a cuerpos de agua a escala de fragmento puede ser una medida apropiada para conservar a las especies en el área, asegurando su movilidad entre sitios relevantes para este grupo.