Advances in technologies for data acquisition, storage and analysis have boosted Acoustic Ecology studies, but protocols are still lacking. There is a need of more research to understand which methodologies can be applied to answer ecological questions in different environments with varying temporal and spatial dynamics. Tropical forests are generally more complex than temperate ones, both in terms of use of acoustic space and species diversity. The seasonally dry tropical forest (SDTF) in Brazil, known as Caatinga, is a threatened biome, with two marked seasons that shape vegetation and animal activity patterns. In this study, we investigate the applicability of passive acoustics in monitoring SDTF, describing the soundscape and tracking diel patterns and seasonal changes. Combining multiple indices, visualization through false colour spectrograms and clustering, we describe the acoustic activity of the main faunal groups that compose the biophonic orchestra in a SDTF area in the Northeast of Brazil. Distinct patterns were found between day – when birds and wind were the main sound sources – and night – with Orthopterans occupying a large frequency band. Other sound sources in the SDTF soundscape included cicada, rain, and anthropogenic influence such as domestic animals, cars and gunshots. Clustering of eleven acoustic indices was useful to distinguish sound patterns from several sources, especially in the dry season. Further investigation within each cluster showed specific relationships among selected indices and different sound sources. Birds were associated with Entropy of the Spectral Peaks (EPS) and Orthopterans also had a relationship with EPS, as well as with Entropy of Average Spectrum (EAS) and High Frequency Cover (HFC). Variation in diel values of these selected indices, as well as the number of samples included in each cluster category, were successfully used to describe the acoustic activity of Birds and Orthopterans and to track changes between rainy and dry seasons. A better understanding of the soundscape dynamics in a highly seasonal tropical environment was achieved by applying cheap and reliable novel methodologies to study biodiversity in geopolitical regions where funding for conservation initiatives is limited.

数据采集​​、存储和分析技术的进步促进了声学生态学研究，但仍然缺乏协议。需要更多的研究来了解哪些方法可以应用于回答具有不同时空动态的不同环境中的生态问题。热带森林通常比温带森林更复杂，无论是在声学空间的使用还是物种多样性方面。巴西的季节性干旱热带森林 (SDTF)，被称为卡廷加，是一个受威胁的生物群落，有两个明显的季节，塑造了植被和动物活动模式。在这项研究中，我们调查了被动声学在监测 SDTF、描述声景和跟踪日照模式和季节性变化中的适用性。结合多个指标，通过假彩色频谱图和聚类进行可视化，我们描述了组成巴西东北部 SDTF 地区生物响乐团的主要动物群的声学活动。在白天（鸟类和风是主要声源时）和夜晚之间发现了不同的模式，直翅目昆虫占据了很大的频段。SDTF 音景中的其他声源包括蝉、雨和人为影响，例如家畜、汽车和枪声。十一个声学指数的聚类有助于区分来自多个来源的声音模式，尤其是在旱季。每个集群内的进一步调查显示了所选指数和不同声源之间的特定关系。鸟类与光谱峰熵 (EPS) 相关，直翅目昆虫也与 EPS 以及平均光谱熵 (EAS) 和高频覆盖 (HFC) 相关。这些选定指数的 diel 值的变化，以及每个集群类别中包含的样本数量，成功地用于描述鸟类和直翅目昆虫的声学活动，并跟踪雨季和旱季之间的变化。通过应用廉价且可靠的新方法来研究保护计划资金有限的地缘政治地区的生物多样性，可以更好地了解高度季节性热带环境中的声景动态。以及每个聚类类别中包含的样本数量，成功地用于描述鸟类和直翅目昆虫的声学活动，并跟踪雨季和旱季之间的变化。通过应用廉价且可靠的新方法来研究保护计划资金有限的地缘政治地区的生物多样性，可以更好地了解高度季节性热带环境中的声景动态。以及每个聚类类别中包含的样本数量，成功地用于描述鸟类和直翅目昆虫的声学活动，并跟踪雨季和旱季之间的变化。通过应用廉价且可靠的新方法来研究保护计划资金有限的地缘政治地区的生物多样性，可以更好地了解高度季节性热带环境中的声景动态。