Márcio Borges-Martins

Climate Change and the Distribution of Neotropical Red-Bellied Toads (Melanophryniscus, Anura, Amphibia): How to Prioritize Species and Populations?

We used species distribution modeling to investigate the potential effects of climate change on 24 species of Neotropical anurans of the genus Melanophryniscus. These toads are small, have limited mobility, and a high percentage are endangered or present restricted geographical distributions. We looked at the changes in the size of suitable climatic regions and in the numbers of known occurrence sites within the distribution limits of all species. We used the MaxEnt algorithm to project current and future suitable climatic areas (a consensus of IPCC scenarios A2a and B2a for 2020 and 2080) for each species. 40% of the species may lose over 50% of their potential distribution area by 2080, whereas 28% of species may lose less than 10%. Four species had over 40% of the currently known occurrence sites outside the predicted 2080 areas. The effect of climate change (decrease in climatic suitable areas) did not differ according to the present distribution area, major habitat type or phylogenetic group of the studied species. We used the estimated decrease in specific suitable climatic range to set a conservation priority rank for Melanophryniscus species. Four species were set to high conservation priority: M. montevidensis, (100% of its original suitable range and all known occurrence points potentially lost by 2080), M. sp.2, M. cambaraensis, and M. tumifrons. Three species (M. spectabilis, M. stelzneri, and M. sp.3) were set between high to intermediate priority (more than 60% decrease in area predicted by 2080); nine species were ranked as intermediate priority, while eight species were ranked as low conservation priority. We suggest that monitoring and conservation actions should be focused primarily on those species and populations that are likely to lose the largest area of suitable climate and the largest number of known populations in the short-term.

Community structure of helminth parasites of the “Cururu” toad, Rhinella icterica (Anura: Bufonidae) from southern Brazil

Sixty specimens of the “cururu” toad, Rhinella icterica (Spix 1824) (Bufonidae), were collected in Campo Belo do Sul, State of Santa Catarina, Brazil, between May 2009 and January 2011, and were examined for the presence of helminth parasites. Nine species of adult helminths were found: Catadiscus cohni, Rudolphitrema rudolphii, Cylindrotaenia sp., Rhabdias fuelleborni, Strongyloides sp., Cosmocerca rara, Cosmocerca brasiliensis, Aplectana elenae, and Oxyascaris sp., in addition to an unidentified adult nematode species. Females of cosmocercid nematodes, proteocephalan plerocercoid, and acanthocephalan cystacanth were found but not identified for lack absolute of taxonomic characters. The sex of the anurans had no influence on prevalence, abundance, and richness of helminth species. Length and body mass of hosts did not influence the prevalence and richness of helminths, while the abundance of R. fuelleborni was significantly correlated with both parameters.

Effects of traffic noise on the calling behavior of two Neotropical hylid frogs

Anthropogenic disturbance has been pointed to as one of the major causes of the world´s biodiversity crisis. Among them, noise pollution is a potential underestimated threat, projected to increase in the next decades accompanying urban expansion. Rising levels of noise pollution may result in negative impacts on species highly dependent on acoustic communication. Amphibians have long served as model organisms for investigating animal acoustic communication because their reproduction depends on transmitting and receiving acoustic signals. A few studies have investigated the effects of anthropogenic noise on anurans, but there is still limited knowledge on how it affects them. In this study, we test the effect of two intensities of traffic noise on calling males of two Neotropical treefrogs species. We expect to record more changes in call parameters, to avoid masking effect, at higher intensity noise treatments, and in the species with higher call/noise frequency overlap. We performed a set of field playback experiments exposing male frogs to road noise at two different intensities (65dB and 75dB). Focal species are Boana bischoffi (high call/noise frequency overlap) and B. leptolineata (low call/noise frequency overlap). Both species changed acoustic parameters during or after the exposure to traffic noise. Advertisement call rate of B. bischoffi decreased during road noise, and dominant frequency decreased over time. Call length of B. leptolineata increased or decreased, depending on the order of noise intensity. We also observed spatial displacement in both species, which moved away from the noise source. Our results provide evidence that traffic noise affects anuran calling behavior, and noise intensity is an important factor affecting how species respond.

Amphibia, Anura, Cycloramphidae, Proceratophrys bigibbosa (Peters, 1872) and Proceratophrys brauni Kwet and Faivovich, 2001: distribution extension and new state record

Proceratophrys Miranda-Ribeiro, 1920 includes 18 species of cycloramphids (Frost 2009) commonly known as the smooth horned frogs (Frank and Ramus 1995). As indicated by the group’s common name, the eyelids of many species are adorned with elongate dermal appendages (for review see Prado and Pombal 2008). Several other species of Proceratophrys lack conspicuous palpebral appendages, including the type species P. bigibbosa (Peters 1872) and P. brauni Kwet and Faivovich 2001. These species are included in the P. bigibbosa species group, which was characterized by Lynch (1971) as lacking hornlike palpebral appendages and having a short, blunt snout, postocular cranial protuberances, and large marginal tubercles on eyelids.

TEMPORAL FLUCTUATIONS IN RAPTOR ABUNDANCES IN GRASSLANDS OF SOUTHEASTERN SOUTH AMERICA

Abstract We conducted 44 roadside surveys on grasslands landscapes of southern Brazil and Uruguay to study temporal changes in raptor abundance. Each route was surveyed twice in fall/winter and twice in spring/summer. Raptor abundance was higher during summer than winter, but did not differ between years. Thirteen of the 33 species recorded showed temporal changes in abundance, or are known to be migrants in the region. White-tailed Kite (Elanus leucurus), Yellow-headed Caracara (Milvago chimachima) and Southern Caracara (Caracara plancus) had higher abundance during fall/winter than spring/summer, which might be attributed to nomadic movements in agricultural landscapes. Changes in abundance of Savanna Hawk (Buteogallus meridionalis) and American Kestrel (Falco sparverius) suggest irruptive or nomadic movements. Turkey Vulture (Cathartes aura), Snail Kite (Rostrhamus sociabilis) and White-tailed Hawk (Geranoaetus albicaudatus) were more abundant in spring/summer than fall/winter, and our results suggest that they are partial migrants in the region. Variations in temperature, water level, and land use in agro-environment as well as dispersion, recruitment, and ephemeral concentration of food resources probably are the causes of fluctuation observed. Our results provide a starting point to better understand raptor temporal fluctuations and abundance in southeastern South America, but further investigations are required. FLUCTUACIONES TEMPORALES EN LAS ABUNDANCIAS DE RAPACES EN PASTIZALES DEL SURESTE DE AMÉRICA DEL SUR Realizamos 44 censos a lo largo de caminos ubicados en paisajes de pastizales del sur de Brasil y Uruguay para estudiar los cambios temporales en las abundancias de rapaces. Cada ruta fue censada dos veces en otoño/invierno y dos veces en primavera/verano. La abundancia de rapaces fue mayor durante el verano que en el invierno, pero no difirió entre años. Trece de las 33 especies registradas evidenciaron cambios temporales en sus abundancias, o es sabido que son migrantes en la región. Elanus leucurus, Milvago chimachima y Caracara plancus tuvieron una mayor abundancia durante otoño/invierno que en primavera/verano, lo que puede ser atribuido a movimientos nómades en los paisajes agrícolas. Los cambios en la abundancia de Buteogallus meridionalis y Falco sparverius sugieren movimientos nómades o de irrupción. Cathartes aura, Rostrhamus sociabilis y Geranoaetus albicaudatus fueron más abundantes en primavera/verano que en otoño/invierno y nuestros resultados sugieren que son migrantes parciales en la región. Las variaciones en la temperatura, el nivel del agua y el uso del suelo en ambientes agrícolas, así como también la dispersión, el reclutamiento y la concentración transitoria de fuentes de alimento son probablemente las causas de la fluctuación observada. Nuestros resultados proporcionan un punto de partida para entender mejor las fluctuaciones temporales de las rapaces y sus abundancias en el sureste de América del Sur; sin embargo, se requieren mayores investigaciones.

Correction: Effects of traffic noise on the calling behavior of two Neotropical hylid frogs

[This corrects the article DOI: 10.1371/journal.pone.0183342.].

Are the unken reflex and the aposematic colouration of Red-Bellied Toads efficient against bird predation?

Aposematic signals as well as body behaviours may be important anti-predator defences. Species of the genus Melanophryniscus are characterised by having toxic lipophilic alkaloids in the skin and for presenting a red ventral colouration, which can be observed when they perform the behaviour called the unken reflex. Both the reflex behaviour and the colouration pattern are described as defence mechanisms. However, there are currently no studies testing their effectiveness against predators. This study aimed to test experimentally if both ventral conspicuous colouration and the unken reflex in Melanophryniscus cambaraensis function as aposematic signals against visually oriented predators (birds). We simulated the species studied using three different clay toad models as follows: (a) in a normal position with green coloured bodies, (b) in the unken reflex position with green coloured body and extremities and (c) in the unken reflex position with a green body and red extremities. Models were distributed on a known M. cambaraensis breeding site and in the adjacent forest. More than half of the attacks on the models were from birds; however, there was no preference for any model type. Thus, just the presence of the red colour associated with the motionless unken reflex position does not seem to prevent attacks from potential predators. It is possible that the effective aposematic signal in Melanophryniscus is achieved through the unken reflex movement together with the subsequent exhibition of the warning colouration and the secretion of toxins.

Aves, Passeriformes, Cotingidae, Phytotoma rutila (Vieillot, 1818): new record in Brazil

The White-tipped Plantcutter Phytotoma rutila has only one documented record for Brazil, that occurred in 1974 in the extreme west of Rio Grande do Sul. We report herein a second record - one individual photographed in April 2009 at a dunefield in the municipality of Capao da Canoa, northern coast of Rio Grande do Sul, about 700 km from the previous one. This new record corroborates the status of vagrant for this species in Brazil.