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Stream Ecology 2014

On Saturday, July 19thfreshwater ecologist and emeritus professor Dr. Mark Oswood came to share his expertise in the Highland Wonders series. This event aimed to increase our community’s understanding of stream ecology, and how riparian zones and streams interact to support and affect populations of aquatic insects. Connections were made between populations of aquatic insects and what their presence indicates about water quality.

 Mark Oswood Indoor Presentation
The event was well attended and began with an indoor presentation in the Chesaw Community Building, which offered an explanation of biological classification, some basics of stream ecology, and how streams take their cues from the land.

Classification: Kingdom > Phylum > Class > Order > Family > Genus > Species. Dr. Oswood explained that we would be focused on identifying macroinvertebrates to the order level. 
   Mark Oswood Indoor PresentationThe audience was pleasantly surprised to discover how captivating aquatic entomology can be when taught by a charismatic instructor who is passionate about his field of study. Combining a keen sense of humor with a well-prepared PowerPoint presentation, Mark held the group’s attention and increased the community’s awareness of, as he quoted E.O. Wilson, “the small things that run the world.” He went on to say, “Many of you are bird watchers. But these small things are the nuts and bolts, and the cogs in the machinery, that make life on earth happen. What I want you to get out of this is that you could do this as a hobby, as an avocation, just like bird watching.”

 Mark Oswood Indoor Presentation
This diagram was part of Mark's presentation and shows the interactions among trophic levels. Mark set the group at ease with an open approach based on understanding the function of aquatic insects and the role that they play in highland streams. “Given that these things are so hard to put names on, maybe we don’t need to put names on them right away,” he said. “We can ask what they do. This is the uniquely American thing: when you meet someone you ask them, ‘What do you do?’ Well you can do that with invertebrates too… you can shake a tarsal claw and ask them ‘What do you do?’ and instead of having a name, you get a function. With all the food that comes into streams, we will ask, ‘Do you eat dead leaves? Do you eat green slime? How do you do it?’” The presentation also discussed the role of salmon as a major gift from the sea, and the interconnectedness of the trophic levels. Mark summed it up with the adage, “No bugs, no fish!”

   Mark Oswood Indoor Presentation
Mark shares from a book that he co-authored about macroinvertebrates, during a demonstration of books and gear that followed the talk.

 Intro at Myers Creek    Intro at Myers Creek
Following the indoor presentation, the group took a field trip to the Myers Creek Mitigation Site north of Chesaw. Mark began with an overview of the process the group would follow, from observing the kick sampling, to moving the sampled “gork” into tubs, to "bug picking," to sorting macroinvertebrates by orders into petri dishes. 

 Mark Oswood Kick Sampling Myers Creek
  Mark Oswood Kick Sampling Myers Creek
Kick sampling with a D-net provided a wide array of macroinvertebrates to study, including a large stonefly larva. Participants gathered around several tables to work on identifying the aquatic insects using laminated charts and magnifying lenses.

Group observes
The group gathers to observe the stonefly larva, streamside.

 Group listens
Participants listen intently as Mark describes the intricate world of aquatic insects in the stream. Much laughter and many “ooo’s and ahhh’s” could be heard as Mark shared a variety of interesting anecdotes about how aquatic insects survive and thrive.
 Exploring the aquatic insects of Myers Creek 
Next, field trip participants scooped the samples into tubs and then "bug picked" the specimens into petri dishes, sorting according to their order. Among the pickings were mayfly, stonefly, caddisfly and black fly larvae, caddisfly pupae, a dragonfly nymph casing, and even two crayfish! 

Exploring the aquatic insects of Myers Creek
Claire asks to hold one of the macroinvertebrates for an up-close look.

Exploring the aquatic insects of Myers Creek
Lee works to identify a macroinvertebrate larva using a laminated chart and magnifying lens. 

Exploring the aquatic insects of Myers Creek
Holly observes life on a rock pulled from the stream.

Crayfish found in Myers Creek

Mayfly found in Myers Creek  
(Above: Mayfly in the family Heptageniidae; note gills on abdomen of larva; also note that this is one of the relatively few mayfly taxa with 2 tails instead of the usual 3 for mayflies)

Stonefly found in Myers Creek
Large stonefly larva found in Myers Creek

Stonefly underneath
Underside of stonefly

Free-living caddisfly  
This green pupa is a free-living caddisfly (Trichoptera), which means that it doesn’t make a case unless it is pupating. This is a Trichoptera family that is entirely predatory and eats other insects, and is almost always long and green (in this part of the world). Other Trichoptera (caddisflies) usually use silk to make cases or spin capture nets for filter-feeding.

Free-living caddisfly
Another free-living caddisfly (Trichoptera)

Mark Oswood lives in the Wenatchee area, retired from the department of Biology and Wildlife and the Institute of Arctic Biology at the University of Alaska Fairbanks, with a research specialty in freshwater ecology. Mark focused mainly on running waters (streams and rivers), with an emphasis on aquatic entomology (the scientific study of insects) and trophic structure of stream ecosystems. He has taught limnology (freshwater science), ecology of streams and rivers, aquatic entomology, as well as introductory biology. Most of his research was on ecology of stream insects, especially biogeography, and decomposition of organic matter. Mark has applied experience studying the effects of heavy metals from mining on streams, and has a side specialty in statistical analysis.

Throughout his career, Mark has taught a wide variety of “introduction to stream ecology” events in classrooms, Elder Hostels, and for government agencies, fly-fishing groups, and conservation organizations. “Seeing the diversity of invertebrates that live in streams can be analogous to a first experience looking at tide pool organisms,” he says. “Plus, aquatic insects are a stream’s way of turning green algae and brown leaves into fish food.” 

Thank you, Mark, for your generous contribution of time and energy in preparing for and offering this excellent learning opportunity for our community!