low-flow fountain darter movement study. background previous studies have described fountain darters...
TRANSCRIPT
![Page 1: Low-Flow Fountain Darter Movement Study. Background Previous studies have described fountain darters as sedentary under stable conditions Some other darter](https://reader030.vdocument.in/reader030/viewer/2022032806/56649f005503460f94c159c8/html5/thumbnails/1.jpg)
Low-Flow Fountain Darter Movement Study
![Page 2: Low-Flow Fountain Darter Movement Study. Background Previous studies have described fountain darters as sedentary under stable conditions Some other darter](https://reader030.vdocument.in/reader030/viewer/2022032806/56649f005503460f94c159c8/html5/thumbnails/2.jpg)
Background
• Previous studies have described fountain darters as sedentary under stable conditions
• Some other darter species have shown a movement response to unfavorable changes in habitat conditions
• Summer algal blooms in Upper Spring Run reduce bryophyte habitat
• Fewer darters encountered by survey efforts
![Page 3: Low-Flow Fountain Darter Movement Study. Background Previous studies have described fountain darters as sedentary under stable conditions Some other darter](https://reader030.vdocument.in/reader030/viewer/2022032806/56649f005503460f94c159c8/html5/thumbnails/3.jpg)
Questions
• Do the conditions that arise in the Upper Spring Run during summer low flows render habitat unsuitable to the extent that darters seek other habitat areas?
• What effect will conditions expected to arise from extreme low flow periods likely have on fountain darter movement?
• How far can darters be expected to move to find suitable habitat?
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Field Study Area
• Confluence of Blieder’s Creek and Upper Spring Run
• Expectation of low flow conditions later this year in USR
• Lack of spring flow inputs to Blieder’s creek provides fluctuation of conditions approximating USR under no flow conditions
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Study Site Temperature Fluctuations
15.00
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25.00
27.00
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31.00
9/8/
2007
3/8/
2008
9/8/
2008
3/8/
2009
9/8/
2009
3/8/
2010
9/8/
2010
3/8/
2011
9/8/
2011
3/8/
2012
9/8/
2012
3/8/
2013
9/8/
2013
Te
mp
era
ture
(°C
)
Date
Thermistor Data: Comal HeadwatersBlieders Cr.
Upper Spring Run
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Field Study Methods
• Use fluorescent VIE to cohort mark darters in Blieder’s creek and USR• Re-sample monthly (minimum) using both visual and net capture
methods• Record vegetation type, height and percent cover• Record standard WQ data
• Distribution (distance) up or downstream of cohort release points will be compared among sampling events using Kolmorogov-Smirnov tests.
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ARC Pond Study
• Investigate use of vegetated vs. open habitat patches by fountain darters
• Homogenous vegetated patches of Ludwigia repens
• VIE marked fountain darters (n=50/ 2 week trial)
• Distribution of darters among vegetated vs non vegetated patches tested by chi-square or Fisher’s exact tests
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ARC Pond Study
• Evaluation of effect of distance on movement among patches
• Distance to each patch from center will change each trial
• Regression of number of movements by distance to patch
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Expected Utility of Results
• Describe movement behaviors of fountain darters relative to changing habitat and environmental conditions.
• Assist in incorporating fountain darter movement into HCP Ecological model.
• Inform SAV restoration efforts to maximize benefit of restoration to fountain darters.