Wetlands provide numerous ecosystem services; one of the most valuable services they can provide people is their natural ability to perform water filtration. I want to understand how connected wetlands are to water quality.
5/14/2014 UPDATE: After much deliberation, I’m taking a different approach to this project and class, and hopefully thesis!
New Research Questions
− Using Finley as a case study, can a wetland refuge improve water quality? To what extent?
a. how can it improve water quality – nutrients – evidence wetlands can act as a nitrogen sink – great in an agriculture heavy area like Corvallis
− How similar or different are invertebrate and plant communities (diversity and abundance as an indication of how “healthy” the ecosystems are) within Finley compared to surrounding streams and mitigated wetlands?
a. R: statistically significant correlations?
b. ArcGIS: spatial relationships (maybe cluster analysis)? (would need to account for spatial autocorrelation of habitat type, etc)
− Historically, how has land use affected the Finley refuge wetlands? How has Finley’s history impacted this study? How may land use affect the wetlands today?
Hypothesis
− ecosystem service of wetlands is improvement in water quality: I hope to show streams leaving wetlands will have a lower quantity of nitrogen than streams entering wetlands
a. may need a lit review: see what improvement is typical and to what extent to have a baseline
– can also compare to other surrounding stream quality data – maybe proximity analysis correlated with change in quality? I expect to see quality, again, improved leaving wetlands than those that don’t interact with the wetlands at all.
– I would expect similar-size nearby mitigated wetlands to show similar results; if different, maybe plant and invert communities can indicate differences in ecosystem health between the refuge and mitigated wetlands.
– I would expect past land use, as well as current surrounding land use, to impact the health of the wetlands and streams – run a land use correlation in comparison to plant communities and nitrogen content of streams?
Also, anyone know of a good land use Shapefile that incorporates the Finley area? Or any other Shapefiles that exist for Finley/surrounding areas? I’d hate to work off of aerial photography if I don’t have to (I’m not familiar with it, so if I do need to go that route any links to tutorials would be great!), any input is appreciated. This is a seed of an idea that can go a lot of ways.
Will update with a map next week!
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A National Wetlands Inventory shapefile of Oregon’s wetlands was clipped to the nine counties that make up the Willamette Valley (county data provided by BLM): Multnomah, Washington, Yamhill, Clackamas, Marion, Polk, Linn, Benton, and Lane Counties. Using wetlands mapped between 1994 and 1996 by The Nature Conservancy of Oregon (funded by the Willamette Basin Geographic Initiative Program and the Environmental Protection Agency (EPA)), data was created that inventoried, classified, and mapped native wetland and riparian plant communities and their threatened biota in the Willamette Valley. I have also clipped 2004 – 2006 stream and lake water quality data from the DEQ to these counties. Furthermore, I have mitigation bank data compiled by ODSL and ODOT developed by The Nature Conservancy of mitigated wetland locations in the Willamette Valley.
I am interested in looking at connectivity of streams to wetlands and the relationship of water quality to wetland location. For connectivity I may compare streams connected to wetlands versus those that are not connected to wetlands. Additionally, I am interested in seeing if the water quality data is different around mitigated wetlands versus natural wetlands. I also have stream and lake water quality data from other years, so measuring statistically significant change over time as well.
I am interested in receiving comments regarding potential statistical analyses to examine connectivity; to compare water quality around mitigated versus natural wetlands; and comparing water quality data over time.
hi Jackie,
It sounds like you want to test the hypothesis that water quality in streams draining from wetlands is different from water quality of streams not draining wetlands? What kind of water quality data do you have and from what sites – can you show this on a map?
Based on what I am imagining, it seems you want to select a subset of streams which drain wetlands and for which you have water quality data – so you need to attribute streams according to these characteristics, and then select a set of streams of comparable characteristics (same drainage area and vegetation/land cover) that don’t drain from wetlands, but have water quality data, and then you want to compare their water quality?
Let me know!
Julia
Hi Jackie!
I’m curious about the timing of your data sets. I’m not familiar with water quality assessments or this line of work, but from my vantage, it seems random to use 1996 wetlands data to assess water quality years later. When you say you have other years of water quality data, do you have the late nineties DEQ data for those areas, too?
Julia’s plan of attack sounds great. Comparisons of similar streams with and without wetlands, or with mitigated or natural wetlands, might be more bite sized than all the streams pictured in your figure. However, finding a definition of “similar” might be challenging. If you could find/create “ecosystem type” or “climatic region type” or even “land use type” to provide context for comparison that would certainly make things more scientific. As a limited GIS user, and complete non-ecologist, I’m no help figuring what sorts of datasets might already be available for classifying that data. Maybe your next commenter will be more helpful!
Rebecca
Hey Julia and Rebecca,
– The streams on the map I have water quality data for. I think the next step is locating the sampling stations at each of those streams for where the DEQ obtained the data, as I discussed with you Julia.
– I can show different stream qualities by selecting attributes for particular pollutants below and above EPA standards, that will isolate the stream line data into at least two categories per pollutant.
– I need to categorize streams by similar attributes like land cover/vegetation/etc and their relation to wetlands – I am unsure of how to select according to closeness/connectivity to wetlands (maybe that’s what the specific sampling location point data would be good for?)
– I used that 1990s vegetation data because it was the most comprehensive veg data available. In the 10 years later stream quality data I have, there might be disparity/inaccuracies to account for. Maybe this would be a good reason to go back in time in quality data too?
Hi Jackie –
Sounds like an interesting project – I wonder if a cluster analysis approach would be useful for you. If you have similar attributes for streams as for wetlands you can run a cluster analysis which will tell you which wetlands are more similar to which streams based on the branch lengths of the produced trees. Then there are a couple other permutation tests that you can run to see if the groups that arise from the cluster are significantly different from one another – addressing the hypothesis Julia suggested.
There is a relatively easy to use package in R that you could use for this – check it out: vegan (http://cran.r-project.org/web/packages/vegan/vegan.pdf). Let me know if you go this multivariate direction with your stuff – I’m doing a lot of this for my dissertation, happy to help.
Caren