I recently attended a “Stream and Buffer Ecology Workshop” at the Stroud Water Research Center in Avondale, Pennsylvania. Stroud is a world-class research facility for fresh water science. This year their “Moorhead Environmental Complex” was awarded a “Platinum LEED” rating, which is the nation’s highest certification for green construction.
The Stroud Water Research Center is by led by perhaps one of the world’s leading scientist in fresh water stream ecology: Dr. Bern Sweeney. He received the Chesapeake Bay Foundation’s “Lifetime Achievement Award” in 2006.
He and his team of scientists helped write the book on why forested stream buffers are so important. I was fortunate to spend a whole day with Dr. Sweeney and his team.
I came away from the experience refueled with enthusiasm for restoring the ecology of our streams. Metaphorically speaking I went to the riparian buffer oracle, asked what the answer to life was and he said, “Keep planting native trees along the streams”.
A stream surrounded by a forested buffer of native trees not only filters out up-gradient pollutants like nitrogen, phosphorous, sediment and pathogens but it is also is capable of detoxifying itself from anthropogenic influences by a factor of 2 to 8.
Microbial activity in the stream is a function of food (energy). Leaves, native leaves, from trees along the stream banks supply this food source. This is the bottom of the aquatic food chain. No trees, no leaves. No leaves, no microbes. If there are no microbes, the rest of the food chain for a healthy stream ecosystem cannot be built.
Temperature is also a huge factor and according to research, an increase in temperature of only a few degrees, greatly affects the presence of both leaf eating and algae eating organisms. Dr. Sweeney stressed that many of these organisms “live on the edge”. He stated that mayfly nymphs for example thrive at 68 degrees F. but perish at 70 degrees. With a warming planet this is all the more reason to plant trees along stream banks.
Leaves from non-native trees won’t work. Research shows that at least some leaf-eating macroinvertebrates are leaf specific. Even within a genus certain leaf eaters prefer certain leaves. Stroud scientists could find no macroinvertebrates that would eat multi-flora rose leaves; furthermore, multi-flora rose leaves were toxic to mayflies (L. cupida)
Bottom line: native trees along our streams here in the temperate, eastern United States, provide the fuel for aquatic ecosystems to function and the cooling mechanism (shade) to keep the temperature of the water in the stream below lethal limits.
So, what we have been doing all these years: Excluding livestock from the streams and planting native hardwood trees along the banks of the streams, is emphatically, the right thing to do and we need to do a lot more. Stream side forested buffers not only filter out incoming pollutants from poor land use, they foster an aquatic ecosystem that is capable of processing pollution as well.
Dr. Sweeney said, “A diverse ecosystem gives the stream increased horsepower to detoxify itself”.
While Dr. Sweeney and other scientists continue their important research on fresh water ecology the message is crystal clear for us field conservationists; steam side forested buffers are imperative to restoring the streams in our communities and for a restored Chesapeake Bay. Let’s continue our work with renewed enthusiasm.
For more information on how you can help, click on the hot-links above or shoot me an email; I’ll be glad to help you find an answer.
The Virginia Working Landscapes is hosting a riparian conservation workshop on June 22 at the Smithsonian Conservation Biology Institute in Front Royal, Virginia. I will be one of the speakers there along with Stroud Scientist Dr. Dave Arscott. There is still room so if you want to come please register here.