HABITAT SUITABILITY CRITERIA FOR THE FOOTHILL YELLOW-LEGGED FROG ( RANA BOYLII )

1. HABITAT SUITABILITY CRITERIA FOR THE FOOTHILL YELLOW-LEGGED FROG (RANA BOYLII) IN THE NORTHERN SIERRA NEVADA AND COAST RANGE OF CALIFORNIA Amy Lind, Sarah Yarnell, and Technical Workgroup I. Background II. Data Set Evaluation and Preliminary Analyses III. Development of Criteria IV. Conclusions and Applications Goal: To develop habitat suitability criteria for the Rana boylii which can be used for instream water flow modeling and habitat availability evaluations.

2. Acknowledgements Technical Workgroup: C. Champe, M. Gard, A. Herman, S. Kupferberg, J. Lynch, M-L. Lynch, R. Peek, D. Smith, K. Turner, S. Wilcox Data Contributions From: PG&E, SMUD, South Feather Water & Power Agency, Devine-Tarbell & Assoc., Garcia & Assoc., Ibis Environmental, Inc., Stillwater Sciences, Spring Rivers Ecological Services, Clara Wheeler, Tom VanWagoner

3. simplified hydrograph Spring Summer Fall Immobile Mobile Life cycle in synchrony with predictable flood / drought regimes

4. Upslope / Upstream / Reach+ Scale Influences e.g., - climatic regime - tributary proximity - valley width - stream gradient - base geology - proximity to off-channel waterbodies Human Influences e.g., - regulated flows - reservoir construction and introduction of exotic species - road construction and erosion - timber harvest effects on woody debris Biological Influences e.g., - native predators - invasive exotic species - prey availability - algae availability - riparian canopy cover and seral stage - woody debris inputs Local Physical Environment e.g., - water temperature - local geomorphology - erosion / sediment regime FYLF oviposition and rearing habitat water depth water velocity substrate composition and sorting Influences on FYLF Habitat Conditions and Context for HSC Development

5. Habitat Variables * Developed List of Key Habitat Variables – 3 Categories - variables related to instream hydrodynamic models (e.g. 2D model) - variables influenced by flow regime, but not typically part of hydrodynamic models - variables not influenced by flow regime but at reach-scale and greater * Focused On Three Characteristics of Instream Environments - water velocity - water depth - substrate use /composition * Rationale - found to be important descriptors of oviposition and rearing habitat conditions in natural history studies and recent research - can be readily used in hydrodynamic models

6. Focal Lifestages * 2 lifestages analyzed egg masses & tadpoles * Rationale - eggs and tadpoles highly aquatic - strongly influenced by changes in flow regimes - application to hydrodynamic model more appropriate - lack of habitat data on post-metamorphic lifestages

7. Reasons Other Datasets Not Used * Missing one or more of focal variables * Missing or limited information on focal lifestages * Not available electronically Selected Datasets by River and Lifestages Analyzed Northern Sierra Nevada Butte Creek – eggs and tadpoles WB Feather - eggs and tadpoles South Fork Feather - eggs Pit River – eggs Coast Range South Fork Eel – tadpoles Final Dataset Selection * Evaluated 31 datasets from 15 rivers; data collected from 1991-2006 * Final habitat data compiled for: individual egg masses, n = 251 tadpole groups (not individual tadpoles), n = 405 * Developed habitat suitability criteria for each river and overall (combined data)

8. Total depth by river Analyses of Habitat Variables * Compared water velocities at egg masses or tadpole groups, at mid-column, and surface * Compared water depths at egg masses or tadpoles and total. * Compared water depth and velocity values among rivers. * Final focal variables: mid-column water velocity, total depth, and substrate (egg attachment or dominant in tad group)

9. Criteria Development * Considered both continuous curves and categorical / rank approaches * Decided on categorial as best first approximation given limited data * 3 Categories: 0 = not suitable, 0.1 = marginal suitability, 1 = high suitability Egg Masses

10. Criteria Development * Considered both continuous curves and categorical / rank approaches * Decided on categorial as best first approximation given limited data * 3 Categories: 0 = not suitable, 0.1 = marginal suitability, 1 = high suitability Egg Masses

11. Criteria Development * Considered both continuous curves and categorical / rank approaches * Decided on categorial as best first approximation given limited data * 3 Categories: 0 = not suitable, 0.1 = marginal suitability, 1 = high suitability Egg Masses

12. Criteria Development * Considered both continuous curves and categorical / rank approaches * Decided on categorial as best first approximation given limited data * 3 Categories: 0 = not suitable, 0.1 = marginal suitability, 1 = high suitability Egg Masses

13. Criteria Development and similarly for Tadpole Groups....

14. Combined River Habitat Suitability Criteria – Egg Masses depths 1 = 0.06-0.47 m 0.1 = 0.02-0.05, 0.48-0.90 m 0 = <0.02,>0.90 m velocities 1 = 0.0-0.09 m/sec 0.1 = 0.10-0.25 m/sec 0 = >0.25 m/sec

15. Combined River Habitat Suitability Criteria – Tadpole Groups depths 1 = 0.02-0.44 m 0.1 = 0.45-1.00 m 0 = <0.02,>1.00 m velocities 1 = 0.00-0.11 m/sec 0.1 = 0.12-0.24 m/sec 0 = >0.24 m/sec

16. Criteria Application * Criteria developed through methods such as these can be used to quantify areas of habitat suitability via instream flow models such as 2-dimensional hydrodynamic models. Consequences of narrow and broadly ranging HSC’s…. stay tuned for next talk for more on 2-D model applications……

17. Next Steps * Further exploration of differences in habitat suitability for different developmental (e.g., Gosner) stages of eggs and tadpoles. * Data on habitat associations for post-metamorphic lifestages. * Validation of suitability criteria in different river systems, including incorporation of habitat data for areas not used by Rana boylii. * Research on relative role and importance of habitat conditions in determining overall distribution and abundance, especially where populations are small or isolated.

18. Table 2. Rana boylii egg mass habitat suitability criteria. n = valid sample size for depth/velocity/substrate if they differed among variables; 0 = not suitable, 0.1 = marginally suitable, 1 = suitable. See text for detailed description of how criteria were derived. 1 - All Rivers for total depth = Butte, West Branch Feather, Pit. 2 - All Rivers for mid-column water velocity and substrate = South Fork Feather, Butte, West Branch Feather, Pit.

19. Table 3. Rana boylii tadpole habitat suitability criteria. n = valid sample size for depth/velocity/substrate if they differed among variables; 0 = not suitable, 0.1 = marginally suitable, 1 = suitable. See text for detailed description of how criteria were derived. 1-All Rivers = Butte, West Branch Feather (South Fork Eel not included).

20. Table 4. Frequency data for Rana boylii egg mass attachment substrate and tadpole group habitat substrate derived from 248 egg masses and 155 tadpole groups. Highlighted (yellow) cells represent the ranked (highest to lowest) substrate types used to reach a total of 90% of the observations. Data are from the following rivers: Egg Masses - Butte, West Branch Feather, South Fork Feather, Pit; Tadpoles - Butte, West Branch Feather (South Fork Eel not included).

21. Eggmasses – WB Feather, Butte Ck, SF Feather, Pit Rivers combined

22. Example Histograms for Individual Rivers Pit River – Egg Masses

23. Tadpoles – WB Feather and Butte Ck combined

24. Example Histograms for Individual Rivers West Branch Feather River – Tadpoles Mid-column velocity m/s