This week Ken and I discussed various ways we could implement landscape elements that could
alter wind dynamics, which in turn could alter the turbulence environment experienced by
plant communities. When it comes to seed dispersal, turbulence is a key process to work with
because it creates more opportunities for seeds to be lifted higher into the wind column, and
thus dispersed longer distances. For some background on turbulence, you first have to think
about laminar flow. Imagine you put a dye trace, or some sort of visible particle, into the wind
so you could track the direction the wind was moving. If your dye trace was experiencing
laminar flow (left side of diagram), then the particles would be moving in straightline winds.
Here, seeds would simply move straight along until they fell out of the wind column. However,
if the winds hit some sort of obstacle or element (at the green arrow below) that creates
turbulent wind conditions, then the dye trace or seeds could get uplifted higher into the air.
Since “time aloft” is a huge determinant of how far seeds disperse, the longer a seed can stay
suspended in the wind column, the farther they can disperse. Thus laminar and turbulent wind
conditions can have very different effects on seed dispersal.
I like the idea of trying to work with directly modifying the landscape to alter the wind dynamics
and see how a more turbulent environment alters the dispersal and establishment of plant
species. To do this, you would need to have some prairie plots that have elements that create
turbulent wind conditions, and some plots that do not have these elements in order to control
for natural colonization processes. I could imagine these plots looking something like this:
Finally, this weekend I volunteered at a local community pollinator garden and learned some
really interesting things about urban lots and gardening in St Louis. It turns out there are over
40,000 empty lots in St Louis, and many of them are owned by the city. There is a deal you can
make with the city, where if you turn an empty lot into a garden, you can lease it for $1/year
until someone wants to develop the land. I do not know all of the details and stipulations for
creating these gardens, but it seems like we might actually be able to find multiple urban lots
here in St Louis with which to create a really great sci/art project for a reasonable price!
Blogged while listening to the Sharon Jones covering Gladys Knight.