The emerging significance of bioacoustics in animal species conservation

Abstract

This review reports on the effects of human activities on animal acoustic signals published in the literature from 1970 to 2009. Almost 5% of the studies on variation in animal communication tested or hypothesized on human impacts, and showed that habitat fragmentation, direct human disturbance, introduced diseases, urbanization, hunting, chemical and noise pollution may challenge animal acoustic behaviour. Although acoustic adaptations to anthropogenic habitats have been documented, human impacts have most often generated neutral variation or potential maladaptive responses. Negative impacts have been postulated in the sexual signals of fishes, amphibians, birds, and mammals; these are concerning as any maladaptive alteration of sexual behaviour may have direct bearings on breeding success and ultimately population growth rate. Acoustic communication also facilitates other vital behaviours influenced by human-driven perturbations. Bat and cetacean echolocation, for instance, is disrupted by noise pollution, whereas bird and mammal alarming is also affected by introduced diseases and hunting. Mammal social signals are sensitive to noise pollution and hunting, and birds selecting habitats by means of acoustic cues are especially vulnerable to habitat loss. Anthropogenic intervention in these cases may have a negative impact on individual survival, recruitment and group cohesion, limiting rescue effects and triggering Allee effects. Published evidence shows that acoustic variation may be used as an early-warning indicator of perturbations even when not directly affecting individual fitness. Acoustic signalling can be studied in a broad range of ecosystems, can be recorded, analyzed, synthesised and played back with relative ease and limited economic budget, and is sensitive to many types of impacts, thus can have great conservation significance.

Anthropogenic noise affects song structure in red-winged blackbirds (Agelaius phoeniceus)

“…tropical forests), some species have been found to converge on songs that have primarily pure tones or narrow frequency bands (Dubois and Martens, 1984;Slabbekoorn and Smith, 2002). Fifth, animals can adjust the pitch of their signals to improve signal transmission (Laiolo, 2010). Green hylia (Hylia prasina), for example, avoid interference from insect sounds by decreasing the pitch of their songs (Kirschel et al, 2009), whereas certain anurans avoid interference from low-frequency stream noise by communicating with ultrasonic frequencies (Feng et al, 2006).…”

Sounds of Indo-Pacific humpback dolphins (Sousa chinensis) in West Hong Kong: A preliminary description

“…Noise pollution is an important issue in marine environments due to the reliance of odontocete cetaceans on acoustic signaling for communication, foraging, and navigation (Laiolo, 2010). This is of particular concern with the Indo-Pacific humpback dolphin population in Hong Kong, where there are many sources of anthropogenic disturbances, e.g., dredging, heavy vessel traffic, chemical pollution, and noise pollution (Wü rsig and Greene, 2002;Jefferson et al, 2009).…”

Avian Resources of the Northern Gulf of Mexico

“…For some indicator species, the trends are clear and different surveys indicate the same patterns (e.g., increases in Brown Pelican, declines for Mottled Duck), but for others, the evidence is conflicting. Thus, the data in this chapter can be examined with a weight of evidence approach, whereby the different types of data are examined in total to determine population status and trends in the Gulf (Burger 2003;Krimsky 2005;Laiolo 2010). Thus, if all (or almost all) data sets suggest that a given species is increasing, it is likely that it is.…”