2023
Rose, JP; Kupferberg, SJ; Peek, RA; Ashton, D; Bettaso, JB; Bobzien, S; Bourque, RM; Breedveld, KGH; Catenazzi, A; Drennan, JE; Gonsolin, E; Grefsrud, M; Herman, AE; House, MR; Kluber, MR; Lind, AJ; Marlow, KR; Striegle, A; Hattem, M; Wheeler, CA; Wilcox, JT; Wiseman, KD; Halstead, BJ
Identifying drivers of population dynamics for a stream breeding amphibian using time series of egg mass counts Journal Article
In: Ecosphere, vol. 14, iss. 8, pp. e4645, 2023.
Abstract | Links | BibTeX | Tags: amphibian declines, amphibian populations, amphibians, Foothill yellow‐legged frog, population structure, stream ecosystems
@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}
}
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.
2013
Catenazzi, Alessandro; Kupferberg, Sarah J.
The importance of thermal conditions to recruitment success in stream-breeding frog populations distributed across a productivity gradient Journal Article
In: Biological Conservation, vol. 168, pp. 40-48, 2013.
Abstract | Links | BibTeX | Tags: amphibian declines, Angelo Reserve, California, climate change, Thermoregulation
@article{Catenazzi2013,
title = {The importance of thermal conditions to recruitment success in stream-breeding frog populations distributed across a productivity gradient},
author = {Alessandro Catenazzi and Sarah J. Kupferberg},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Catenazzi_2013_BioConser.pdf},
doi = {10.1016/j.biocon.2013.09.010},
year = {2013},
date = {2013-12-01},
journal = {Biological Conservation},
volume = {168},
pages = {40-48},
abstract = {Predicting the vulnerability of species to environmental change requires integrating observations of individual ecophysiological and behavioral responses with community level constraints. To assess the response of stream-breeding frogs (Rana boylii) to thermal stressors, such as cold water released from the depths of upstream reservoirs or warm water that results from climate change, we combined field manipulations with population censuses and environmental correlations. These frogs migrate between shaded tributaries and open canopy mainstem channels to oviposit where algal food is abundant for tadpoles. Within this context of spatial variation in aquatic primary productivity, we evaluated whether tadpole thermoregulatory behavior is a useful indicator of survival to metamorphosis and adult distribution. In a thermal gradient, tadpoles selected temperatures between 16.5–22.2 °C (mean, 19.60 ± 0.6 °C). We reared tadpoles in streams colder, warmer, or close to thermal preference. Temperature effects were mediated through algal quantity and quality. Mortality increased with increasing deviation from preferred temperatures, but the effects were ameliorated when tadpole diet was supplemented with algae (Cladophora glomerata with epiphytic nitrogen-rich diatoms, Epithemia spp.) harvested from sun-lit channels. Distribution of frogs in free-flowing and dammed reaches within a northern California watershed was in equilibrium with tadpole thermal preference. Populations were dense (⩾125 breeding females/km) where July water temperatures averaged 17.5–19 °C in 2010, a relatively cool summer. Below 16 °C, frogs were sparse with open canopy and absent under closed canopy. Integration of thermoregulatory behavior with ecological context can thus be useful to forecast recruitment when the thermal regimes of rivers are altered by anthropogenic factors.},
keywords = {amphibian declines, Angelo Reserve, California, climate change, Thermoregulation},
pubstate = {published},
tppubtype = {article}
}
Predicting the vulnerability of species to environmental change requires integrating observations of individual ecophysiological and behavioral responses with community level constraints. To assess the response of stream-breeding frogs (Rana boylii) to thermal stressors, such as cold water released from the depths of upstream reservoirs or warm water that results from climate change, we combined field manipulations with population censuses and environmental correlations. These frogs migrate between shaded tributaries and open canopy mainstem channels to oviposit where algal food is abundant for tadpoles. Within this context of spatial variation in aquatic primary productivity, we evaluated whether tadpole thermoregulatory behavior is a useful indicator of survival to metamorphosis and adult distribution. In a thermal gradient, tadpoles selected temperatures between 16.5–22.2 °C (mean, 19.60 ± 0.6 °C). We reared tadpoles in streams colder, warmer, or close to thermal preference. Temperature effects were mediated through algal quantity and quality. Mortality increased with increasing deviation from preferred temperatures, but the effects were ameliorated when tadpole diet was supplemented with algae (Cladophora glomerata with epiphytic nitrogen-rich diatoms, Epithemia spp.) harvested from sun-lit channels. Distribution of frogs in free-flowing and dammed reaches within a northern California watershed was in equilibrium with tadpole thermal preference. Populations were dense (⩾125 breeding females/km) where July water temperatures averaged 17.5–19 °C in 2010, a relatively cool summer. Below 16 °C, frogs were sparse with open canopy and absent under closed canopy. Integration of thermoregulatory behavior with ecological context can thus be useful to forecast recruitment when the thermal regimes of rivers are altered by anthropogenic factors.
2012
Kupferberg, Sarah J.; Palen, Wendy J.; Lind, Amy J.; Bobzien, Steve; Catenazzi, Alessandro; Drennan, Joe; Power, Mary E.
Effects of Flow Regimes Altered by Dams on Survival, Population Declines, and Range-Wide Losses of California River-Breeding Frogs Journal Article
In: Conservation Biology, vol. 26, no. 3, pp. 513-524, 2012.
Abstract | Links | BibTeX | Tags: amphibian declines, hydropower, Rana boylii, Rana draytonii
@article{Kupferberg2012,
title = {Effects of Flow Regimes Altered by Dams on Survival, Population Declines, and Range-Wide Losses of California River-Breeding Frogs},
author = {Sarah J. Kupferberg and Wendy J. Palen and Amy J. Lind and Steve Bobzien and Alessandro Catenazzi and Joe Drennan and Mary E. Power},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Kupferberg_Flowregdamsfrogs_ConsBio2012.pdf
https://angelo.berkeley.edu/wp-content/uploads/sites/59/Kupferberg_SupMat_ConsBio2012.pdf},
doi = {10.1111/j.1523-1739.2012.01837.x},
year = {2012},
date = {2012-05-17},
journal = {Conservation Biology},
volume = {26},
number = {3},
pages = {513-524},
abstract = {Widespread alteration of natural hydrologic patterns by large dams combined with peak demands for power and water delivery during summer months have resulted in frequent aseasonal flow pulses in rivers of western North America. Native species in these ecosystems have evolved with predictable annual flood- drought cycles; thus, their likelihood of persistence may decrease in response to disruption of the seasonal synchrony between stable low-flow conditions and reproduction. We evaluated whether altered flow regimes affected 2 native frogs in California and Oregon (U.S.A.) at 4 spatial and temporal extents. We examined changes in species distribution over approximately 50 years, current population density in 11 regulated and 16 unregulated rivers, temporal trends in abundance among populations occupying rivers with different hydrologic histories, and within-year patterns of survival relative to seasonal hydrology. The foothill yellow- legged frog (Rana boylii), which breeds only in flowing water, is more likely to be absent downstream of large dams than in free-flowing rivers, and breeding populations are on average 5 times smaller in regulated rivers than in unregulated rivers. Time series data (range = 8 − 19 years) from 5 populations of yellow- legged frogs and 2 populations of California red-legged frogs (R. draytonii) across a gradient of natural to highly artificial timing and magnitude of flooding indicate that variability of flows in spring and summer is strongly correlated with high mortality of early life stages and subsequent decreases in densities of adult females. Flow management that better mimics natural flow timing is likely to promote persistence of these species and others with similar phenology.},
keywords = {amphibian declines, hydropower, Rana boylii, Rana draytonii},
pubstate = {published},
tppubtype = {article}
}
Widespread alteration of natural hydrologic patterns by large dams combined with peak demands for power and water delivery during summer months have resulted in frequent aseasonal flow pulses in rivers of western North America. Native species in these ecosystems have evolved with predictable annual flood- drought cycles; thus, their likelihood of persistence may decrease in response to disruption of the seasonal synchrony between stable low-flow conditions and reproduction. We evaluated whether altered flow regimes affected 2 native frogs in California and Oregon (U.S.A.) at 4 spatial and temporal extents. We examined changes in species distribution over approximately 50 years, current population density in 11 regulated and 16 unregulated rivers, temporal trends in abundance among populations occupying rivers with different hydrologic histories, and within-year patterns of survival relative to seasonal hydrology. The foothill yellow- legged frog (Rana boylii), which breeds only in flowing water, is more likely to be absent downstream of large dams than in free-flowing rivers, and breeding populations are on average 5 times smaller in regulated rivers than in unregulated rivers. Time series data (range = 8 − 19 years) from 5 populations of yellow- legged frogs and 2 populations of California red-legged frogs (R. draytonii) across a gradient of natural to highly artificial timing and magnitude of flooding indicate that variability of flows in spring and summer is strongly correlated with high mortality of early life stages and subsequent decreases in densities of adult females. Flow management that better mimics natural flow timing is likely to promote persistence of these species and others with similar phenology.