Noise and Ecosystems

Inwood Hill Park
Inwood Hill Park

Research suggests noise can rattle an ecosystem. Birds, for example, rely on their voices to woo mates, size up rivals, scrounge for dinner. Horn blasts and engine revs can scramble auditory cues. Birds try singing louder, singing at a higher frequency, singing at night. Some abandon their nests altogether. This can trigger an ecological cascade, one that extends even to vegetation; noise can scare away some birds that would normally scatter seeds.

—Ashley Powers, “Preserving the Quietest Places” in The California Sunday Magazine

More on sound and noise:



There’s no right way out of a riptide


Everything we’ve done points to the fact that there’s not one single message that works. Sometimes swim parallel is great, sometimes it doesn’t work. Same for floating.”

It’s a view that the Surf Life Saving Australia has taken, too. After working with Brander, they’ve updated their messaging. Rips are a complex, dynamic hazard and the multitude of variables—swimming ability, current strength, circulation, wave size—make the threat nearly impossible to solve with one-size-fits-all advice. No single “escape strategy” is appropriate all the time, the group now says, and lifeguards in Australia currently recommend combining the advice from both MacMahan’s circulation concept and traditionalists like Brewster. If you’re not a strong swimmer, stay afloat and signal for help; if you can swim, consider paddling parallel to the beach toward breaking waves—though be mindful of the potential circulating current. “All responses,” the group concedes, “have their pitfalls.” [Bold added]

—David Ferry, “Everything You Know About Surviving Rip Currents Is Wrong” on Outside

While this quote may refer to rip tides, I think the concept of dynamic complexity and variability could just as easily apply to schools and school systems. As we’ve explored here before, in the face of complexity, sometimes you’ve just got to try multiple strategies until something sticks. And sometimes,  you’ve just got to pick something and stick to it. It is not always so easy to predict what will lead to a breakthrough.

Like students, plants give up after years of failure, too

By Famartin (Own work) [CC BY-SA 3.0 (, via Wikimedia Commons
“The plant life of Australia’s outback may have “given up”, according to satellite-based maps tracking the impact of changing climatic conditions, such as rainfall and temperature, on the world’s ecosystems.

“The study suggests the vegetation of our interior does not respond to sudden increases in rainfall because it has “learned” that drought will soon follow. . . .

“‘Sometimes when you subject an ecosystem to some kind of disturbance, such as a drought or fire, they behave differently depending on their past,’ he explained. . . .

“‘They don’t care if it is good favourable conditions now, because they know it is temporary and it is not worth investing in growing more at this time because they become bigger and it is a lot more to care of when the drought returns,’ he said.”

–Dani Cooper, “Global satellite map highlights sensitivity of Australia’s plants to changes in rainfall and temperature” on ABC Science News

A Brain is More than the Sum of its Parts

“Why does the brain transcend bell-curve averages?  One possible explanation is that the brain lacks a privileged scale because its functioning cannot be reduced to component parts (i.e., neurons).  Rather, it is the complex interactions between parts which give rise to phenomena at all spatial and temporal scales. . . . Like averages, reductionism is deeply ingrained in our scientific thinking.  Water is explained in terms of molecules, molecules in terms of atoms, etc.  If the brain is reducible to simpler parts, it should also exhibit a privileged scale of organization.

And yet, it does not.  A unifying mechanism for power law behavior in the brain and other systems is that of self-organized criticality (SOC).  According to this model, systems such as the brain operate on the brink of instability, exhibiting slow processes that build energy and fast processes that dissipate energy.  In such systems, small causes have effects of many sizes. Imagine you are at the beach building a sand pile.  As you add sand, the pile gets taller until its slope reaches a critical angle where it can barely support more sand.  Steadily adding more sand will result in avalanches ranging in size from a few grains to significant portions of the pile.  The avalanches are a scale invariant emergent property. Studying individual grains of sand tells you little about avalanches.”

—Joel Frohlich, “Scale Invariance: A Cautionary Tale Against Reductionism” on Knowing Neurons (HT Alexis Madrigal’s newsletter)

Grim Reminder of Thresholds Crossed

By Philip Sclater (The Book of Antelopes) [Public domain], via Wikimedia Commons
A grim reminder that we never know when invisible ecological thresholds may be crossed: more than half of an endangered antelope species in Central Asia died off within a month.

We are entering an era of increasing turbulence due to factors related to climate change, of which the saiga antelope is one casualty.

Check out this post for more on the concept of thresholds.