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.
Aims
We identify alien reptiles and amphibians, invaders or not, in Brazil and evaluate the following: (a) which alien species are found in the country; (b) where they originate from; (c) how they are distributed; (d) why and how they were introduced; and (e) which factors affect the record incidences and local richness of these species.
Location
Brazil.
Methods
We conduct a comprehensive survey of different data sources to collect records of alien amphibians and reptiles. We then use a causal model approach to evaluate the influence of space, climate, anthropogenic predictors, and introduction pathways on alien richness and number of records.
Results
We find a total of 2,292 records of 136 species of alien reptiles and amphibians. Although species from many regions of the world can be found, most are snakes, lizards and anurans originating in the Americas. Although records of alien amphibians and reptiles are found throughout Brazil, they are concentrated in more economically developed areas. Socio‐economic measures have both a direct and indirect causal relationship over the distribution of alien species and affect all introduction pathways, which are key factors explaining the alien species’ distribution. Pet trade was directly related to alien diversity, while all the three introduction pathways contributed to explain the number of records.
Main Conclusions
We reveal a high diversity of alien amphibians and reptiles widespread in an already megadiverse country. The finding that alien richness occurs in highly populated and wealthy areas and that it is linked to the pet trade helps to direct efforts towards the surveillance and prevention of the spread of alien species in Brazil. A higher record incidence is associated with species introduced accidentally or for human consumption, mainly represented by a few already invasive widespread species, impairing management measures.
The images in Fig 1 are incorrectly switched. The image that appears as A should be labeled as B, and the image that appears as B should be labeled as A. The authors have provided a corrected version below.
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