Publications

@article{Rose2023,

title = {Identifying drivers of population dynamics for a stream breeding amphibian using time series of egg mass counts},

author = {JP Rose and SJ Kupferberg and RA Peek and D Ashton and JB Bettaso and S Bobzien and RM Bourque and KGH Breedveld and A Catenazzi and JE Drennan and E Gonsolin and M Grefsrud and AE Herman and MR House and MR Kluber and AJ Lind and KR Marlow and A Striegle and M Hattem and CA Wheeler and JT Wilcox and KD Wiseman and BJ Halstead},

editor = {AM Kramer},

url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Ecosphere-2023-Rose.pdf},

doi = {10.1002/ecs2.4645},

year  = {2023},

date = {2023-08-24},

urldate = {2023-08-24},

journal = {Ecosphere},

volume = {14},

issue = {8},

pages = {e4645},

abstract = {The decline in amphibian populations is one of the starkest examples of the biodiversity crisis. For stream breeding amphibians, alterations to natural flow regimes by dams, water diversions, and climate change have been implicated in declines and extirpations. Identifying drivers of amphibian declines requires long time series of abundance data because amphibian populations can exhibit high natural variability. Multiple population viability analysis (MPVA) models integrate abundance data and share information from different populations to estimate how environmental factors influence population growth. Flow alteration has been linked to declines and extirpations in the Foothill Yellow-legged Frog (Rana boylii), a stream breeding amphibian native to California and Oregon. To date, no study has jointly analyzed abundance data from populations throughout the range of R. boylii in an MPVA model. We compiled time series of egg mass counts (an index of adult female abundance) from R. boylii populations in 36 focal streams and fit an MPVA model to quantify how streamflow metrics, stream temperature, and surrounding land cover affect population growth. We found population growth was positively related to stream temperature and was higher in the years following a wet year with high total annual streamflow. Density dependence was weakest (i.e., carrying capacity was highest) for streams with high seasonality of streamflow and intermediate rates of change in streamflow during spring. Our results highlight how altered streamflow can further increase the risk of decline for R. boylii populations. Managing stream conditions to better match natural flow and thermal regimes would benefit the conservation of R. boylii populations.},

keywords = {amphibian declines, amphibian populations, amphibians, Foothill yellow‐legged frog, population structure, stream ecosystems},

pubstate = {published},

tppubtype = {article}

}

@article{Yarnell2012,

title = {Dynamic flow modelling of riverine amphibian habitat with application to regulated flow management},

author = {S. M. Yarnell and A. J. Lind and J. F. Mount},

url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Yarnell_2012_RivResApplic.pdf},

doi = {10.1002/rra.1447},

year  = {2012},

date = {2012-02-01},

journal = {River Research and Applications},

volume = {28},

number = {2},

pages = {177-191},

abstract = {In regulated rivers, relicensing of hydropower projects can provide an opportunity to change flow regimes and reduce negative effects on sensitive aquatic biota. The volume of flow, timing and ramping rate of spring spills, and magnitude of aseasonal pulsed flows have potentially negative effects on the early life stages of amphibians, such as the Foothill yellow-legged frog (Rana boylii). Two-dimensional hydrodynamic modeling is one method to evaluate potential effects of flow variation on frog egg masses and tadpoles. We explored the usefulness of this technique by modeling habitat suitability under several pulsed flow scenarios in two river reaches in northern California, USA. We conducted analyses beyond simple weighted usable area calculations, such as quantifying the risk of scour or stranding, in order to quantify potential loss under different flow scenarios. The modeling results provided information on potential susceptibility to flow fluctuations as well as the influence of channel morphology on habitat suitability. Under each flow scenario, low percentages of suitable habitat remained suitable or were ‘buffered’ from the pulse, creating high potential for scour of egg masses or tadpoles. However, due to differences in channel morphologies, the wide, shallow study site provided 2-3 times the buffering capacity of the entrenched study site.},

keywords = {amphibians, dynamic flow modelling, flow management},

pubstate = {published},

tppubtype = {article}

}

@article{Kupferberg1996,

title = {Hydrologic and geomorphic factors affecting conservation of a river-breeding frog (Rana boylii)},

author = {Sarah J. Kupferberg},

url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Kupferberg_EcolApp1996.pdf},

doi = {http://dx.doi.org/10.2307/2269611},

year  = {1996},

date = {1996-11-00},

journal = {Ecological Applications},

volume = {6},

number = {4},

pages = {1332-1344},

abstract = {Organisms that live in highly variable environments, such as rivers, rely on adaptations to withstand and recover from disturbance. These adaptations include behavioral traits, such as habitat preference and plasticity of reproductive timing, that minimize the effects of discharge fluctuation. Studies linking hydrologic regime, habitat preference, and population processes, however, are predominantly limited to fish. Information on other sensitive taxa is necessary to facilitate conservation of multispecies assemblages and restoration of biodiversity in degraded river channels. I studied the functional relationship between physical habitat and reproduction of the foothills yellow-legged frog (Rana boylii), a California State Species of Special Concern. From 1992 to 1994, I mapped breeding sites along 5.3 km of the South Fork Eel River in northern California and monitored egg survival to hatching. Frogs selected sites over a range of spatial scales and timed their egg-laying to avoid fluctuations in river stage and current velocity associated with changes in discharge. The main sources of mortality were desiccation and subsequent predation of eggs in a dry year and scour from substrate in wet years, both caused by changes in stage and velocity. At the finest spatial scale, frogs attached eggs to cobbles and boulders at lower than ambient flow velocities. At larger scales, breeding sites were near confluences of tributary drainages and were located in wide, shallow reaches. Clutches laid in relatively narrower and deeper channels had poor survival in rainy as well as dry springs. Most breeding sites were used repeatedly, despite between- and within-year variation in spring stage of the river. This pattern of site selection suggests that conservation of Rana boylii may be enhanced by maintaining or restoring channels with shapes that provide stable habitat over a range of river stages.},

keywords = {amphibians, Anura, frogs, geomorphology, hydrology, oviposition, physical habitat, Rana boylii, reproductive success, river, spatial scale},

pubstate = {published},

tppubtype = {article}

}