Low-Flow Fountain Darter Movement Study
Feb 22, 2016
Low-Flow Fountain Darter Movement Study
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
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?
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
Study Site Temperature Fluctuations
15.00
17.00
19.00
21.00
23.00
25.00
27.00
29.00
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
Tem
pera
ture
(°C
)
Date
Thermistor Data: Comal Headwaters Blieders Cr.
Upper Spring Run
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.
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
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
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.