Krause and the Niche Hypothesis

Some reading I’ve been doing recently has me thinking hard about the direction I want to take my research (and the blog) this year. I was recently introduced by a friend (whose work on wilding the city stresses the importance of green spaces in urban environments) to Bernard Krause, a pioneer of electronic synthesis turned acoustic ecologist who proposes an interesting addition to the canon of evolutionary outcomes.

Krause’s Niche Hypothesis suggests that species develop vocal characteristics that occupy bandwidths in specific regions of the frequency spectrum. This reduces the chance that their mating and warning calls will clash with those of other species, thereby increasing their chances of finding a mate and succesfully communicating coming dangers. In noisy environments animals find it harder to distinguish the noises of their own kind from those made by other species. In the worst case scenario, a species will become extinct due to an inability to successfully communicate with each other.

Many ecosystems have achieved a natural equilibrium from centuries of acoustic evolution. Krause has observed a balance range of animal frequencies in what we might consider some of the most cacophonous environments on the planet. After some eye-opening work in the Venezuelan rainforest, he sought to test his theory. By characterising and tracking individual species’ mating calls in similarly dense acoustic surroundings, he has graphed the way which this natural give and take works. A variety of unique sonic footprints can be seen working around each other in such a way that no one part of the frequency spectrum is ever too over-populated.

While his theory is still contested in scientific circles, it is gaining serious traction and Krause provides some compelling evidence to back it up. In subsequent posts I’ll explore in more detail his ideas as well as those of his detractors.

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