Tag Archives: niche hypothesis

Forest For the Trees

Like many dissatisfied scientists before him, Bernie Krause devised his most important theory after becoming frustrated with the research modus operandi in his field. Before he arrived on the scene, field work as a “bio-acoustician” usually involved honing in on and studying very particular sounds. Scientists were concerned with Individuals species and did their utmost to isolate vocalisations from the sum total of sound around them. This tendency can be attributed to the greater ease with which it is possible to grasp and measure individual, isolated recordings within rigid academic convention, which values measurable results and concrete conclusions, usually for a very good reason. But such methods yield questionable efficacy when it comes to studying making sense of natural soundscapes . As Krause notes:

Abstracting the voice of a single creature from a habitat and trying to understand it out of context is a little like trying to play Samuel Barber’s “Adagio For Strings” absent a violin section as part of the orchestra

Without its accompaniments, the individual part is virtually devoid of meaning. Krause suggests that the great composers know this. I would add that audio engineers, always seeking to find the ideal balance of a many-layered mix, and indeed any great artist must also know this.

Considered from the principles of its conception, Krause’s Niche Hypothesis can serve as a guide and inspiration for those frustrated by short sightedness and singular goals mired in specific, immutable presumptions. This is not to advocate some spacey new age approach to everything and specialised research plays a hugely important role in scientific development. But you and I and the scientific establishment might just occasionally benefit from venturing outside established norms and taking a holistic approach, as Krause has done. In this way, we may just see the forest for the trees.


The Benefits of Long Term Acoustic Observation

One of the crucial factors in Bernie Krause’s formulation of the Niche Hypothesis and in his sometimes dire predictions about the decline of natural soundscapes is the benefit afforded by many years of close listening to soundscapes. Long-term listening, just like long-term observation, can reveal things that a cursory examination can not.

This is exactly the idea that drives the Muskegon River Watershed project, a joint initiative aimed at measuring the biodiversity of the Muskegon River over a long period of time. The project was set up by Stuart Gage of Michigan State University, along with Bryan Pijanowski of Purdue. Together, they deployed solar powered microphones at specific points throughout the region. Recordings are relayed to the scientists via satellite and are logged and entered into the database. At the end of the project, the recordings will be compared and conclusions will be drawn regarding the long-term health of the region.

Another ecologist with similar ideas about the usefulness the aural examination of natural processes over the long-term is Almo Farina of Italy’s Urbino University. He studies the relationship between bird activities and the surrounding landscape by examining recordings made from a selection of microphones strewn across a valley floor by a cable car. His findings are in accord with the Niche Hypothesis. He states that “some birds sing only after another species becomes silent, and vice versa”. This indicates a natural give and take, exactly as Krause describes. He explains further, that “when you find acoustic overlap, this means that the community could be affected by some habitat disturbance”.

Both of these projects allow a completely fresh perspective on the health of natural environments and allow scientists to asses long-term affects of human activities on these environments. They also reinforce the importance and effectiveness of holistic approaches to studying natural soundscapes. They indicate a need for us avoid the tendency to focus in on particular sounds, a habit which only contributes to a warped impression of the soundscapes we find ourselves amidst. The sound of Tui or a Bellbird may be lovely, but if we ignore their increasing irregularity, we may stand to lose them in future.

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.