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

Te

mp

era

ture

(°C

)

Date

Thermistor Data: Comal HeadwatersBlieders 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.