ambience: stream, Sierra Nevada
One way to find out whether a stream is healthy or not, is by monitoring the insects and other small creatures that live there. I’m Jim Metzner, and this is the Pulse of the Planet. Dave Herbst of the Sierra Nevada Aquatic Research Lab regularly takes the pulse of local streams by checking out the resident bugs. Their habits, body shapes, and life stages give him a wealth of useful information.
“And the nice thing about the bug is that unlike the water quality sample that’s a chemical sample, you don’t just go in and take a sample that represents the condition that exists in that particular piece of water in that particular time. Because the bugs live in the stream, and they integrate everything that’s coming downstream, over the period of their entire life cycle, which can range from months to years. And so, when you turn over a rock, you’re seeing the integrated product of the survival, of a whole host of organisms having been exposed to a history of environmental change in the aquatic habitat. And so, some of the ones that are indicators of declining water quality, are organisms such as midges for example, which is a family of flies that have little worm-like larvae, and you’ll often find those in areas where there’s a lot more sediment in the stream channel. So if you turn over a rock, and what you see is a whole bunch of little squirming worm like critters, it’s an indication that the habitat quality has declined because those organisms have become the dominant thing in the system.”
By tracking insect populations from year to year, Dave Herbst can get a dynamic picture of how stream habitats evolve.
To hear about our new CD, please visit pulseplanet.com. Pulse of the Planet is made possible by the National Science Foundation. I’m Jim Metzner.
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