Description Soundscape ecology

sounds produced physical features of environment such running water contribute natural soundscapes

soundscape ecology bio- , geo-acoustic branch of ecology studies acoustic signatures whatever source within landscape (the soundscape). soundscape of given region can viewed sum of 3 separate sound sources: geophony first sound heard on earth. non-biological in nature, consists of effect of wind in trees or grasses, water flowing in stream, waves @ ocean or lake shoreline, , movement of earth. biophony term introduced soundscape ecologist, bernie krause, in 1998, first began express soundscape in terms of acoustic sources. biophony refers collective acoustic signatures generated sound-producing organisms in given habitat @ given moment. includes vocalizations used conspecific communication in cases. anthropophony term introduced bernie krause along colleague, stuart gage. represents human sources heavily populated urban regions contains information intentionally produced communication sound receiver. expression in various combinations of these acoustic features across space , time generate unique soundscapes.

soundscape ecologists seek investigate structure of soundscapes, explain how generated, , study how organisms interrelate acoustically. number of hypotheses have been proposed explain structure of soundscapes, particularly elements of biophony. instance, ecological theory known acoustic adaptation hypothesis predicts acoustic signals of animals altered in different physical environments in order maximize propagation through habitat. in addition, acoustic signals organisms may under selective pressure minimize frequency (pitch) overlap other auditory features of environment. acoustic niche hypothesis analogous classical ecological concept of niche partitioning. suggests acoustic signals in environment should display frequency partitioning result of selection acting maximize effectiveness of intraspecific communication different species. observations of frequency differentiation among insects, birds, , anurans support acoustic niche hypothesis. organisms may partition vocalization frequencies avoid overlap pervasive geophonic sounds. example, territorial communication in frog species takes place partially in high frequency ultrasonic spectrum. communication method represents evolutionary adaptation frogs riparian habitat running water produces constant low frequency sound. invasive species introduce new sounds soundscapes can disrupt acoustic niche partitioning in native communities, process known biophonic invasion. although adaptation acoustic niches may explain frequency structure of soundscapes, spatial variation in sound generated environmental gradients in altitude, latitude, or habitat disturbance. these gradients may alter relative contributions of biophony, geophony, , anthrophony soundscape. example, when compared unaltered habitats, regions high levels of urban land-use have increased levels of anthrophony , decreased physical , organismal sound sources. soundscapes typically exhibit temporal patterns, daily , seasonal cycles being particularly prominent. these patterns generated communities of organisms contribute biophony. example, birds chorus heavily @ dawn , dusk while anurans call @ night; timing of these vocalization events may have evolved minimize temporal overlap other elements of soundscape.