As part of my Aquatic Ecosystems graduate class, I wrote a little interpretive story of a feature of a local water body system. I chose to narrate the importance of riparian zone trees and their leaves on aquatic creek life.

“It is a cool, misty sort of autumn day at Hollow Creek. The trees along the bank show their deep red and yellow hues and the color is reflected in the trickling creek waters below. A blustery wind makes the branches of the Red Oak shiver. A deep red, burgundy leaf breaks off from its stem, leaving a scar behind, and flutters down during this process called abscission. The wind catches the leaf and carries it to the moving, or lotic, creek below. 

The leaf is quickly caught up by the water and swept away. The leaf travels a few meters through the riffles, and then slows as it enters a section of pooled water. There, the Red Oak leaf drifts until it bumps gently into a rock and some tangled branches that have trapped previous leaves. The water collects overtop of the still leaf, and it settles down with other, now-dingy brown colored American Beech, White Oak, and Sycamore leaves.

As the water continues to flow overtop and past the Red Oak leaf over the next few days into weeks, its color begins to fade. What is happening?!  The once deep red leaf turns brown, like the rest of the leaves trapped here. This seems to be the end of the journey…. But wait – a host of life forms is attracted to where the oak leaf sits – maybe the journey has ended, but its purpose in the stream has just begun!

As the pigments are leached into the water, it’s remaining nutrients are pulled too. These nutrients fill the area, attracting many types of microscopic life. Algae starts to grow on the leaf, loving the new nutritive addition to the water. The leaf becomes soft and flexible, much unlike its rigid and brittle life it had on land. As bacteria and fungi grow and feed on the oak leaf, it becomes conditioned and slippery. Is this now the end of the line – being food for the good bacteria?

Just as the leaf undergoes this process and all seems to be the end, a new life-form approaches, using its tiny mouthparts to nibble on a section of the leaf. This creature appears so small and weak – it needs fuel and the Red Oak leaf is glad to be of more service. It’s a good thing that it became so soft and pliable. It would have been extremely difficult for this little creature to fragment, or shred, the leaf earlier! As it shreds the leaf, it makes itself at home, wiggling it’s long, tannish-brown body along, dragging its two tails behind. More of these larvae head over to do the same.

The oak leaf, once bright green and full of energy from the sun, contributed to feeding its tree. Now, even after abscessing from its tree, it has more life and nutrients left to give to these Stonefly larvae who have made a home amongst the fungi, algae, and bacteria, allowing this life cycle to thrive.”

Further Reading & Resources

• http://www.nybg.org/files/forest/OwenRobinson_December2012..pdf
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5838082/#:~:text=Aquatic%20shredders%2C%20mainly%20macroinvertebrates%2C%20can,particulate%20organic%20matter%20(FPOM).
• https://extension.psu.edu/riparian-buffers-for-wildlife

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