Latest news from the Sierras research for Confluence:streamwater, handwriting and urban curbs
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Ahh, stream life in my home mountains, the Sierra Nevada - carnivorous plants, underwater photos, teamwork and sustained attention. I’ve been surveying streams and their tributaries with invertebrate biologists David Herbst, Bruce Medhurst and Ian Bell. We took an astonishing array of measurements from hundred-and-fifty meter sections at each stream, so that insect populations - the bugs who recycle fallen leaves and wood and a primary indicator of ecosystem resilience - can be correlated to changes in water and air temperature, shape of channel, flow velocity, water chemistry and other things. I joined them on four of twenty-four sites they've been monitoring every year, now six years in to a ten year project: a reference curve for environmental change. For the next ten days I have a desk in their lab; they’ll sort out the sampled algae and invertebrates and log numbers into databases while I draw, visit more streams, and write - considering how to bring aspects of their work to the average urban citizen.
More to come – but if you wish not to receive periodic updates, please let me know: it’s nothing personal! (click 'unsubscribe' at the bottom)
Ian Bell doing a stream-side sort of aquatic insects from leafy debris
Sundew (Drosera species) in the fen alongside upper Nelson Creek. (Fen: a bog on a slope, so the water and nutrients are in motion.) Their sticky mucus is being studied for gluing medical implants in humans.
Ian, Dave and Bruce record channel depth, substrate particle size and note any leaves, algae, etc on the rocks.
Underwater, the darker lumps are Glossoma species, 'tortoiseshell' insects that add rocks to their exoskeletons for disguise and protection. They graze on algae and fungus.
One of the bigger predators on the stream bottom (about an inch) - a Stonefly (genus Droneuria) - also prey for fish and other insects. These guys take a year or two to mature so can be especially vulnerable to annual changes in stream levels and temperatures.
Shadows and constant motion; how do they do it? what is it like to be at home in a stream?
For more about this project, please visit my page at
Copyright © 2015 Todd Gilens, All rights reserved.

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