Project Design Recap
To paraphrase the objectives laid out in the Project Design, my intentions are to elucidate how dams impact the ‘normal’ paradigm of a stream and its community. (Ahem. The Ecological Effects of Damming.)
Field Work: The Gathering, outlined the number of replicates and habitat locales:
The data collected will be used to quantify and compare:
>Water Quality (Organic Pollution, Physicochemical Parameters, Biotic Interactions)
>Trophic Guild Composition (Functional Feeding Groups)
>Biodiversity (Taxa Richness)
along longitudinal dimension of a the river, as well as against the theoretical projections made by The River Continuum Concept.
Field Work: The Gathering, outlined the number of replicates and habitat locales:
3 Sites [K,E,H]
[1]
3 Replicates per habitat [K, E(Above, Below) + H]
Count approximately 100 specimens per habitat
____________________
15 samples
15 samples
15 samples translates to 5 habitat assessments and 15 jars that need processing.
Indexing and Analysis
There's no real magic to it.
[2]
Processing the samples for comparison entails dumping the critters out on a sorting tray and indexing them. To quantify the sample, the specimens are organized by order and or (to better account for functional feeding groups) family, then assigned a biotic value based on the order or family's pollution tolerance (provided by your chosen biotic index).
Then you do a little math to get your official biotic value and BAM! Infographics.
But if I might back track just a bit, I'd like to take a moment to review the role and use of a biotic index.
But if I might back track just a bit, I'd like to take a moment to review the role and use of a biotic index.
Biotic Indices
As mentioned in Interpreting Water Quality, a biotic index is a scale used in water quality assessment. Legitimate biologists have assigned pollution tolerance values to different benthic macroinvertebrates (BMIs) families based on their tolerance to organic pollution. The values are on a scale from 1 (least tolerant) to 10 (most tolerant). Organic pollution depresses oxygen levels; oxygen levels delimit a biotic community; ergo, robust water quality assessment tool.
** Of course, not just any index will do. The science behind the scales is a little more sensitive than I care to divulge, but each index is customized to a particular region... An intermittent creek in the The Texas Hill country would fair poorly on a scale tailored for perennial streams in western Great Lakes region; clearly an inappropriate metric in this scenario.
Aaaaaanyway. Given our locale, there are several viable biotic indices to choose from... [R.W. Bode scale, Hilsenhoff's Biotic Index (HBI) 1987, etc.]
For this study, referenced. I referenced a Paul's Biotic Index (PBI), a hybrid of several existent scales. (See Below)
And lastly another disclaimer!
*Certain sampling methods do significantly affect the taxa collected (Ahem. That's what makes the method semi-qualitative). My mobility in the field was somewhat limited (especially in deep water situations), but I did my best to sample from a variety of microhabitats to best represent the transects.
[3]And lastly another disclaimer!
*Certain sampling methods do significantly affect the taxa collected (Ahem. That's what makes the method semi-qualitative). My mobility in the field was somewhat limited (especially in deep water situations), but I did my best to sample from a variety of microhabitats to best represent the transects.
Some Digestible Formats
Habitat Assessments >>>Habitat Photos and Biotic Values by site: [K...] [E...] [H...]
The Data in fine Infographic form>>>
Refs--
Engevold, Paul. PBI and Trophic Structure. N.p.: n.p., n.d. Print.
Engevold, Paul. Stream Comparisons - The Parts Equal the Whole. N.p.: n.p., n.d. Print.
"Citizen Stream Monitoring - Data Sheets." Citizen Stream Monitoring - Data Sheets. N.p., n.d. Web. 11 Oct. 2012. <http://watermonitoring.uwex.edu/wav/monitoring/sheets.html>.
Lenz, Bernard N., and Michael A. Miller. Comparison of Aquatic Macroinvertebrate Samples Collected Using Different Field Methods. [Reston, Va]: U.S. Dept. of the Interior, U.S. Geological Survey, 1996. Print.
Murdoch, Tom, Martha Cheo, and Kate O'Laughlin. The Streamkeeper's Field Guide: Watershed Inventory and Stream Monitoring Methods. Everett, WA: Adopt-a-Stream Foundation, 1996. Print.
Images:
[1] Image generated using Google Maps
[3] Chart replicated from PBI and Trophic Structure, Engevold, Paul
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