​​​​​​​​​​​​​​​​​​​​​Ecoacoustics in the Chilean Biodiversity hotspot: unveiling the structuring of acoustic communities across the landscape. Fondecyt Regular 1261684 (2026-2029).

PI: Felipe N. Moreno Gómez, COIs: Mario Penna Varela, Rodrigo Gutiérrez Aguilar y Fernando Córdova Lepe

​​​​​Several animal species use sounds to interact with conspecific and heterospecific individuals and with their abiotic environment. These sounds are highly relevant traits as they are generally used in reproductive contexts, and therefore alterations on their properties may ultimately affect population persistence. The ensemble of species that produce sounds within a given area conform an acoustic community. Generally, each species within a community produces distinctive signals, and the distribution of these sounds generates an acoustic signature known as the community signal space, which is a multidimensional space encompassing the spectral and temporal components of the signals of the species involved. Identifying the factors that determine the spatio-temporal characteristics of the signal space of communities contributes to the understanding of the evolution of acoustic communication traits and also provides insights on the effects of intra- and inter-specific interactions on community structure and their assembly processes. 

Different hypotheses have been proposed for explaining the characteristics of community signal space. Studies conducted in the last two decades have related the structure of acoustic communities to a diversity of factors that provide support to the different hypotheses proposed. These studies outlined showing such a variety of results for diverse species and environments prompt the need to perform additional studies encompassing concurrent analyses of multiple factors. Such an approach would contribute a better understanding of the spatiotemporal trends in acoustic communities and their signal space characteristics. In recent years there has been a development of devices and analyses allowing to perform passive acoustic monitoring at large spatiotemporal scales, leading to the emergence of Ecoacoustics in which the environmental sounds are studied in an ecological context. Within this framework, coupled with other environmental sensors and geographic information, it is possible to unveil potential factors shaping the structure of natural acoustic communities and the negative effects of global change. The occurrence of anthropogenic factors altering natural environments indicates the need to perform more studies implementing an integrative approach. In addition to acoustic traits, phylogenetic relatedness, body size, and heterogeneity of habitat types, the incorporation of pollutants such as anthropogenic noise, and the effects of ongoing climatic change are needed. The acoustic traits of some species may change in response to these disturbances, and by this via other species of an acoustic community can also be affected.

The Chilean biodiversity hotspot is a globally recognized region relevant for conservation due to the high level of endemism and the occurrence of negative anthropogenic impacts threatening biodiversity. Within this region there are natural reserves that include different forest types that are surrounded by areas with different land uses encompassing a gradient of anthropogenic alterations and environmental conditions. The main objective of this proposal is to evaluate factors shaping the spatiotemporal trends of acoustic communities and signal space characteristics. To achieve this, a combination of passive acoustic monitoring, automated detection of species, acoustic diversity indices and statistical analyses will be performed. Under natural conditions in unaltered environments, we expect that the characteristics of the multidimensional acoustic space of communities are a result of determinants imposing different outcomes. A pattern of overdispersion in the acoustic space will reflect the negative effects of signal masking between heterospecifics. Alternatively, a clustered pattern in the acoustic space would result from selection on signal design for maximizing communication distance within specific habitats. However, clustering could also result from the positive effects of information transfer between heterospecifics belonging to species having similar signaling characteristics. Nonetheless, the patterns of acoustic space may not result from the interaction between species through signals, but as a by-product of the distribution of species body masses and its constraints on signal characteristics, or due to retained trait characteristics during evolutionary history. Furthermore, it is possible that anthropogenic disturbances impose additional conditions that would modify the acoustic space of communities. Specifically, the process of land use change would generate modifications in community structure, leading to more homogeneous and less diverse assemblages, resulting in modified acoustic spaces. In addition, anthropogenic noise may produce signal masking, resulting in clustered acoustic spaces that do not overlap with anthropogenic noise. Furthermore, environmental temperature variations may affect differentially the calling activity of endothermic and ectothermic species, as the effects of temperature are of higher importance on ectotherms, which would likely reduce its contributions to the acoustic space at extreme temperatures, resulting in acoustic spaces having gaps.​