Absence of acoustic niche partitioning in an anuran community of Chiapas, Mexico

Abstract

Species that are part of a community may be restricted by available resources. One of them is the acoustic space, where if there is overlap, communication between conspecifics and, potentially, reproduction can be affected. For this reason, it is expected that communities of anurans that present a marked seasonality have a segregation of niche in the acoustic space, due to their overlap in time. Using automatic recording systems (SGA) and manual recordings (370 hours of recording), we recorded the acoustic activity and vocalizations of a community of anurans in Nahá, Chiapas, Mexico during the period October 2013 to June 2014. From 216 audio cuts belonging to 7 species, we analyzed the recordings and analyzed 15 acoustic characteristics for each species in order to evaluate the spatial, temporal and structural overlap of the acoustic niche, in addition to estimating the amplitude of the niche by calculating the hypervolume. We found that the spatial overlap was very low, while the temporal overlap was very high and a marked phenology can be observed (June, August and September on average > 0.58). The structural acoustic niche overlap was also high and significant according to the Czekanowski index. However, despite the fact that the hypervolumes were similar, the segregation of the use of the dominant frequency was very noticeable. Although we did not observe acoustic niche partitioning in the community, it is very likely that there is an evolutionary trade-off between acoustic overlap related to communication networks that, although it means competition, represents at the same time protection against predators.