Proposed Research

Proposed Research

The need for future monitoring of this restoration project is important, but the complexity of this landscape with it's integration of urban and natural environments further complicates this.  The presence and abundance of chemicals can be easily measured, but may not always indicate ecosystem health.  Wetlands are highly connected to environmental processes that occur both up- and downstream, and urbanization can affect these connections.  To better restore the ecological functioning of the Duwamish River Wetlands, I propose that restored areas be monitored for several key indicators so that we can measure the effects of the cleanup process.


Photograph by Tom Quinn, University of Washington

Salmon

Salmon from the Duwamish River are safe to eat because they do not spend enough time in the river to build up high levels of toxic chemicals.  However, this does not mean they are not adversely affected by pollution in the river.  As stated earlier, one study found that 90% of salmon at one site who passed through the Duwamish River died before they could spawn (14).  Multiple salmon spawning sites upstream from the Duwamish River should be monitored in a long term study and include information from before, during, and after the cleanup process.

Objectives:  Monitor the health of Duwamish River salmon populations.

Hypothesis:  The restoration of wetland habitat and reduction in harmful chemicals should increase the abundance of Duwamish River salmon.

Methods:  Choose a number of random salmon spawning sites upstream from the Duwamish River.  Measure the number of salmon returning each year as well as the number of fish who spawn and the size of eggs/clutches.  These measurements should be compared to salmon spawning measurements in less polluted rivers in the Puget Sound area to determine the local effects from the Duwamish.  My experimental groups will be all of the Duwamish River salmon populations and I will use multiple other salmon populations from various rivers leading into the Puget Sound as my control groups.

Photo by Tom Reese from the Seattle Times Reclaiming the Duwamish River April 16, 2011

Birds

There are many species of birds who inhabit the Duwamish River wetland system.  While habitat loss has severely diminished their populations in this area, the effects of pollution are less well known.

Objectives:  Determine possible impacts of pollution on resident bird populations

Hypothesis:  Since birds tend to be at a higher trophic level, they will accumulate toxins through the ingestion of plants, invertebrates or fish.  This will lead to lower fecundity and developmental problems.

Methods:  Collect tissue samples from birds that reside in the Duwamish River wetlands and analyze them for increased levels of toxins.  Autopsy dead birds found and examine them for any abnormalities.  Measure the species richness and abundance of multiple restoration sites as well as clutch and egg size.  Due to the large number of birds who reside in the area, it would be necessary to limit this to several species.  I would choose birds that have different feeding habits (i.e. invertebrate predators and scavengers).

I would also like to compare the relative effect of this pollution on different species of birds.  If we could determine which species are most effected then we could use them as an umbrella for future monitoring.  In order to accomplish this we would monitor the health of multiple species. For an even larger range we could choose several native species and several migratory species. This would be our experimental group and we would measure their fitness using population density, fecundity, offspring survival rates, and general mortality rates as markers.  For the control group we would examine similar populations of each species along other rivers nearby in the Puget Sound area, and measure them for the same markers.  One issue with this study is the effects that each local environment (including abiotic and species interactions factors) might have on the populations, and how this could skew our results.  However, I feel that along with the other proposed studies that this one could give us a better understanding of the overall impacts the pollution of the Duwamish River has had on the local environment, and help us with future monitoring efforts.