From September 2-12, 2011, the CNSC science staff, along with Dr. Jon Davenport (soon to be of the University of Montana) guided an EarthWatch team through the fieldwork for an autumn wetlands project. Working with EarthWatch volunteers gives us the people power that is every ecologist’s dream, but also offers a unique opportunity to share the world of research in Churchill. I enjoyed watching the participants discover “the little fleas” that live in all the water around the CNSC just as much as seeing them see their first bear, or 20th bald eagle.
Because the team has come and gone, I wanted to give a synopsis of what we did out there and provide an update on what we have found with the data so far. We sampled 28 wetlands and pond habitats during the 10-days the EarthWatch team was here; from the coast near Dump Beach, and all the way to the end of Twin Lakes Rd. For each wetland we collected physical and water quality data, as well as samples of zooplankton and a census of predators (Stickleback fish, Damselfly and Dragonfly larvae). Once we had identified and counted all the zooplankton and predators, we used a sub-sample to conduct three feeding trial experiments in the lab. The goal was to match up patterns of zooplankton and predator distribution observed in the field with lab experiments that examined consumption rates and prey choice of the different predators. This was no small feat for such a short time period, but as the old adage goes, many hands make light work.
Well since the departure of our EarthWatch volunteers we have been busy working on analyses of the field and lab data and we have some preliminary results to share!
For the field data:
- We looked for relationships between variation in environmental parameters (pH, size of wetland, conductivity etc.) and differences in the communities present. For example, were certain zooplankton groups or types of dragonfly larvae more likely to be found in wetlands with a particular conductivity range?
- We found that there was a lot of variation in zooplankton communities that was not explained by any of the environmental or physical variables that we included in the analysis (though we may get different results when we include nutrient data, but we’ll have to wait on that one- our water samples still have to be processed down south).
For the feeding trials:
- We had some difficulties recovering individuals from our first trial (zooplankton are small…), and so looked primarily at our second and third trials.
- We found that Stickleback fish were the most voracious predators in the trials, generally consuming both Daphnia (water fleas) and copepods with the same gusto.
- Some of the other predators used, i.e. damselfly larvae and one type of dragonfly larvae were more discriminate diners, preferring either Daphnia or copepods when given the menu option.
We are still examining the data and double checking our work, but it seems like we also see connections between wetlands that showed absence or low density of either Daphnia or copepods with the presence of specific predators- which is further backed up by the results of our feeding trials.
Stay tuned as we dive further into analyses!
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