Anurans living in species-rich assemblages may experience acoustic niche overlap. To deal with potential masking interference during reproductive activity, species can present acoustic partitioning based on differences in calling period. Studies addressing this question in tropical assemblages have mainly focused on the seasonal scale, and little is known about nightly variation in calling. Here, we reported on phenology and abundance of five tropical anuran assemblages at both seasonal and daily scale and tested the effects of temperature and relative humidity on calling activity patterns of 19 species. Based on 420 hourly acoustic surveys, an overall peak of calling activity in between the first and fourth hour after sunset was identified by Rayleigh’s circular test, with a gradual decrease until sunrise. This nightly pattern was followed by most of the species in the assemblages and similarly observed for species presence and abundance of calling males. The acoustic niche overlap was greater than expected by chance within the assemblages, while no pattern of coincidence or segregation was found for the syntopic congeneric species (Dendropsophus, Boana and Leptodactylus). Moreover, the calling activity of the assemblages, measured as richness and diversity of calling species, was negatively influenced by air and water temperature and positively by relative humidity. Thus, climatic variables act as driver factors to determine calling activity and reproduction of anurans at daily scale. The absence of a segregation pattern at the assembly or genus levels in the calling activity over time indicates that the use of the acoustic temporal niche is not a limiting resource for Cerrado anurans.

中文翻译：

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巴西塞拉多（Cerrado）的无尾类动物召唤活动的夜间模式

生活在物种丰富的种群中的无尾类动物可能会遇到声学利基重叠。为了应对生殖活动中的潜在掩蔽干扰，物种可以根据通话时间的差异进行声音划分。针对热带集合体中这个问题的研究主要集中在季节尺度上，而对夜间呼叫变化的了解很少。在这里，我们报道了五个季节性和日常规模的热带无水组合的物候和丰度，并测试了温度和相对湿度对19种物种呼唤活动模式的影响。根据420个小时的声学调查，瑞利循环试验确定了日落后第一个小时到第四个小时之间通话活动的总体高峰，直到日出之前逐渐下降。这种夜间模式随后出现在集合中的大多数物种上，并且类似地观察到呼叫的雄性中物种的存在和数量。声音生态位重叠大于偶然的组合中的预期，而没有发现同系属同类的重合或分离模式（Dendropsophus，Boana和Leptodactylus）。而且，以呼气物种的丰富度和多样性来衡量的集合的呼气活动受到空气和水温的不利影响，而受到相对湿度的不利影响。因此，气候变量是决定日常活动的呼唤活动和无脊椎动物繁殖的驱动因素。随着时间的推移，在通话活动中，装配或属级别上没有分离模式，这表明声学时空利基的使用不是塞拉多无脊椎动物的限制资源。