2022
Lapides, D
The Case of California’s Missing Streamflow Presentation
07.07.2022.
BibTeX | Tags: California, ERCZO, Stream Flow
@misc{Lapides2022c,
title = {The Case of California’s Missing Streamflow},
author = {D Lapides},
year = {2022},
date = {2022-07-07},
issue = {US Forest Service Pacific Southwest},
keywords = {California, ERCZO, Stream Flow},
pubstate = {published},
tppubtype = {presentation}
}
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.
2007
McNeely, C.; Power, M. E.
Spatial variation in caddisfly grazing regimes within a northern California watershed Journal Article
In: Ecology, vol. 88, no. 10, pp. 2609-2619, 2007.
Abstract | Links | BibTeX | Tags: Angelo Coast Range Reserve, California, USA; armored grazer; caddisfly; landscape; phenology; threshold; trophic level; watershed
@article{McNeely2007,
title = {Spatial variation in caddisfly grazing regimes within a northern California watershed},
author = {C. McNeely and M. E. Power},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/McNeely_2007_Ecology.pdf},
doi = {10.1890/06-0796.1},
year = {2007},
date = {2007-10-01},
journal = {Ecology},
volume = {88},
number = {10},
pages = {2609-2619},
abstract = {Ecologists seek better understanding of why species interactions change across space and time in natural communities. In streams, species effects on resources and community structure may change as physical characteristics of the stream environment change along drainage networks. We examined spatial and seasonal effects of armored grazers using a small-scale exclusion experiment that was replicated in streams of different drainage areas. Effects of grazing varied with stream size and were related to variation in grazer abundance and phenology. We identified three distinct grazing regimes and a stream size (drainage area [DA]) threshold corresponding to a shift from one to two functional trophic levels. In streams with DA < 1 km2, armored grazers did not reduce biomass of algal biofilms. In slightly larger streams (2-3 km2 DA), the armored grazer guild was dominated by bivoltine Glossosoma. These caddisflies persisted and limited algal biofilms throughout the summer in one of these streams. In the largest tributaries (DA > 10 km2), the grazer guild was dominated by univoltine caddisflies, and grazing limited algal biofilms in early summer, but not late summer, after caddisflies pupated. Drainage area is a useful predictor of spatial transitions in food web interactions within and among watersheds. Quantifying the drainage area threshold at which interactions change in catchments with differing geology, vegetation, hydrology, climate, land use, or species pools should help build the understanding we need to forecast ecological responses to environmental change.},
keywords = {Angelo Coast Range Reserve, California, USA; armored grazer; caddisfly; landscape; phenology; threshold; trophic level; watershed},
pubstate = {published},
tppubtype = {article}
}
Ecologists seek better understanding of why species interactions change across space and time in natural communities. In streams, species effects on resources and community structure may change as physical characteristics of the stream environment change along drainage networks. We examined spatial and seasonal effects of armored grazers using a small-scale exclusion experiment that was replicated in streams of different drainage areas. Effects of grazing varied with stream size and were related to variation in grazer abundance and phenology. We identified three distinct grazing regimes and a stream size (drainage area [DA]) threshold corresponding to a shift from one to two functional trophic levels. In streams with DA < 1 km2, armored grazers did not reduce biomass of algal biofilms. In slightly larger streams (2-3 km2 DA), the armored grazer guild was dominated by bivoltine Glossosoma. These caddisflies persisted and limited algal biofilms throughout the summer in one of these streams. In the largest tributaries (DA > 10 km2), the grazer guild was dominated by univoltine caddisflies, and grazing limited algal biofilms in early summer, but not late summer, after caddisflies pupated. Drainage area is a useful predictor of spatial transitions in food web interactions within and among watersheds. Quantifying the drainage area threshold at which interactions change in catchments with differing geology, vegetation, hydrology, climate, land use, or species pools should help build the understanding we need to forecast ecological responses to environmental change.
2006
Feldman, C. R.; Spicer, G. S.
Comparative phylogeography of woodland reptiles in California: repeated patterns of cladogenesis and population expansion Journal Article
In: Molecular ecology, vol. 15, no. 8, pp. 2201-2222, 2006.
Abstract | Links | BibTeX | Tags: California, Charina, Comparative phylogeography, Contia, demographic history, Diadophi s, Elgaria, Lampropeltis, tree-mapping
@article{Feldman2006,
title = {Comparative phylogeography of woodland reptiles in California: repeated patterns of cladogenesis and population expansion},
author = {C. R. Feldman and G. S. Spicer},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Feldman_2006_MolEco.pdf},
doi = {10.1111/j.1365-294X.2006.02930.x},
year = {2006},
date = {2006-05-19},
journal = {Molecular ecology},
volume = {15},
number = {8},
pages = {2201-2222},
abstract = {The ultimate goal of comparative phylogeographical analyses is to infer processes of diversification from contemporary geographical patterns of genetic diversity. When such studies are employed across diverse groups in an array of communities, it may be difficult to discover common evolutionary and ecological processes associated with diversification. In order to identify taxa that have responded in a similar fashion to historical events, we conducted comparative phylogeographical analyses on a phylogenetically and ecologically limited set of taxa. Here, we focus on a group of squamate reptiles (snakes and lizards) that share similar ecological requirements and generally occupy the same communities in the western USA. At a gross level, deep genetic division in Contia tenuis, Diadophis punctatus, Elgaria multicarinata, the Charina bottae complex, and Lampropeltis zonata are often concordant in the Transverse Ranges, the Monterey Bay and Sacramento-San Joaquin Delta region, and the southern Sierra Nevada in California. Molecular clock estimates suggest that major phyletic breaks within many of these taxa roughly coincide temporally, and may correspond to important geological events. Furthermore, significant congruence between the phylogeographies of E. multicarinata and L. zonata suggests that the succession of vicariance and dispersal events in these species progressed in concert. Such congruence suggests that E. multicarinata and L. zonata have occupied the same communities through time. However, across our entire multi-taxon data set, the sequence of branching events rarely match between sympatric taxa, indicating the importance of subtle differences in life history features as well as random processes in creating unique genetic patterns. Lastly, coalescent and noncoalescent estimates of population expansion suggest that populations in the more southerly distributed clades of C. tenuis, D. punctatus, E. multicarinata, and L. zonata have been stable, while populations in more northerly clades appear to have recently expanded. This concerted demographic response is consistent with palaeontological data and previous phylogeographical work that suggests that woodland habitat has become more restricted in southern California, but more widespread in the North during Holocene warming. Future phylogeographical work focusing on allied and ecologically associated taxa may add insight into the ecological and evolutionary processes that yield current patterns of genetic diversity.},
keywords = {California, Charina, Comparative phylogeography, Contia, demographic history, Diadophi s, Elgaria, Lampropeltis, tree-mapping},
pubstate = {published},
tppubtype = {article}
}
The ultimate goal of comparative phylogeographical analyses is to infer processes of diversification from contemporary geographical patterns of genetic diversity. When such studies are employed across diverse groups in an array of communities, it may be difficult to discover common evolutionary and ecological processes associated with diversification. In order to identify taxa that have responded in a similar fashion to historical events, we conducted comparative phylogeographical analyses on a phylogenetically and ecologically limited set of taxa. Here, we focus on a group of squamate reptiles (snakes and lizards) that share similar ecological requirements and generally occupy the same communities in the western USA. At a gross level, deep genetic division in Contia tenuis, Diadophis punctatus, Elgaria multicarinata, the Charina bottae complex, and Lampropeltis zonata are often concordant in the Transverse Ranges, the Monterey Bay and Sacramento-San Joaquin Delta region, and the southern Sierra Nevada in California. Molecular clock estimates suggest that major phyletic breaks within many of these taxa roughly coincide temporally, and may correspond to important geological events. Furthermore, significant congruence between the phylogeographies of E. multicarinata and L. zonata suggests that the succession of vicariance and dispersal events in these species progressed in concert. Such congruence suggests that E. multicarinata and L. zonata have occupied the same communities through time. However, across our entire multi-taxon data set, the sequence of branching events rarely match between sympatric taxa, indicating the importance of subtle differences in life history features as well as random processes in creating unique genetic patterns. Lastly, coalescent and noncoalescent estimates of population expansion suggest that populations in the more southerly distributed clades of C. tenuis, D. punctatus, E. multicarinata, and L. zonata have been stable, while populations in more northerly clades appear to have recently expanded. This concerted demographic response is consistent with palaeontological data and previous phylogeographical work that suggests that woodland habitat has become more restricted in southern California, but more widespread in the North during Holocene warming. Future phylogeographical work focusing on allied and ecologically associated taxa may add insight into the ecological and evolutionary processes that yield current patterns of genetic diversity.
Howard, J. K.; Cuffey, K. M.
The functional role of native freshwater mussels in the fluvial benthic environment Journal Article
In: Freshwater Biology, vol. 51, no. 3, pp. 460-474, 2006.
Abstract | Links | BibTeX | Tags: benthic, biodeposit, California, fluvial, food web, freshwater mussels, functional role, trophic
@article{Howard2006,
title = {The functional role of native freshwater mussels in the fluvial benthic environment},
author = {J. K. Howard and K. M. Cuffey},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Howard_2006_FreshBio.pdf},
doi = {10.1111/j.1365-2427.2005.01507.x},
year = {2006},
date = {2006-02-10},
journal = {Freshwater Biology},
volume = {51},
number = {3},
pages = {460-474},
abstract = {1. Freshwater mussels are the dominant consumer biomass in many fluvial systems. As filter feeding grazers, mussels can remove large amounts of particulate matter from the water column and transfer these resources to the substrate as biodeposits (agglutinated mussel faeces and pseudofaeces). Mussel biodeposits are a nutrient rich and easily assimilated food source and therefore may have significant relevance to benthic community structure. This study examines the functional role of Margaritifera falcata in the South Fork Eel River, California.
2. We addressed two main questions: (i) Do mussels increase benthic resources in this system? (ii) If so, does this alter macroinvertebrate community structure?
3. Measurements and enclosure experiments in the South Fork Eel River show that mussels can play a significant role in local food webs by increasing available fine particulate matter (both organic and inorganic) on the substrate. We document increased benthic macroinvertebrate biomass for predators and collectors (Leptophlebidae) in the presence of mussels, but only in late summer.},
keywords = {benthic, biodeposit, California, fluvial, food web, freshwater mussels, functional role, trophic},
pubstate = {published},
tppubtype = {article}
}
1. Freshwater mussels are the dominant consumer biomass in many fluvial systems. As filter feeding grazers, mussels can remove large amounts of particulate matter from the water column and transfer these resources to the substrate as biodeposits (agglutinated mussel faeces and pseudofaeces). Mussel biodeposits are a nutrient rich and easily assimilated food source and therefore may have significant relevance to benthic community structure. This study examines the functional role of Margaritifera falcata in the South Fork Eel River, California.
2. We addressed two main questions: (i) Do mussels increase benthic resources in this system? (ii) If so, does this alter macroinvertebrate community structure?
3. Measurements and enclosure experiments in the South Fork Eel River show that mussels can play a significant role in local food webs by increasing available fine particulate matter (both organic and inorganic) on the substrate. We document increased benthic macroinvertebrate biomass for predators and collectors (Leptophlebidae) in the presence of mussels, but only in late summer.
2. We addressed two main questions: (i) Do mussels increase benthic resources in this system? (ii) If so, does this alter macroinvertebrate community structure?
3. Measurements and enclosure experiments in the South Fork Eel River show that mussels can play a significant role in local food webs by increasing available fine particulate matter (both organic and inorganic) on the substrate. We document increased benthic macroinvertebrate biomass for predators and collectors (Leptophlebidae) in the presence of mussels, but only in late summer.
Howard, Jeanette K.; Cuffey, Kurt M.
Factors controlling the age structure of Margaritifera falcata in 2 northern California streams Journal Article
In: Journal of the North American Benthological Society, vol. 25, no. 3, pp. 677-690, 2006.
Abstract | Links | BibTeX | Tags: age structure, annual rings, California, discharge, freshwater mussels, Margaritifera falcata, mortality, recruitment
@article{Howard2006b,
title = {Factors controlling the age structure of Margaritifera falcata in 2 northern California streams},
author = {Jeanette K. Howard and Kurt M. Cuffey},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Howard_2006_Bentho.pdf},
doi = {10.1899/0887-3593(2006)25[677:FCTASO]2.0.CO;2},
year = {2006},
date = {2006-01-01},
journal = {Journal of the North American Benthological Society},
volume = {25},
number = {3},
pages = {677-690},
abstract = {Freshwater mussels are long-lived and relatively stationary organisms that form annual rings, so they provide excellent opportunities for studying how population properties such as age structure relate to environmental influences on recruitment and mortality. We investigated population dynamics of the freshwater pearl mussel, Margaritifera falcata, in 2 northern California Coast Range rivers, the South Fork Eel and the Navarro. We used field observations and inverse theoretical modeling to assess age structures and identify factors that control population demographics. Distinctly different mortality rates for young (<20 y) and old (≥20 y) mussels were observed in the South Fork Eel, and recruitment and mortality both were related to river discharge regimes. Margaritifera falcata recruited more successfully during low-discharge than during high-discharge years, and a 2-fold increase in discharge caused a 60% decline in recruitment success. Active annual recruitment (˜1100–1800 ind./y) was observed in the South Fork Eel, whereas recruitment has been low or nonexistent during the past 30 y in the Navarro. This difference probably is a consequence of the influence of 2 non-mutually exclusive factors: landuse history and host-fish abundance. The Navarro watershed has extensive timber harvesting and orchard/vineyard agriculture and has had severe declines in fish populations, whereas large sections of the South Fork Eel pass through protected land and the river has retained its historical fish populations. Investigation of the factors that shape local M. falcata population age structures yielded insights into the influence of environmental variables and history on mortality and recruitment that will aid conservation of this endangered family.},
keywords = {age structure, annual rings, California, discharge, freshwater mussels, Margaritifera falcata, mortality, recruitment},
pubstate = {published},
tppubtype = {article}
}
Freshwater mussels are long-lived and relatively stationary organisms that form annual rings, so they provide excellent opportunities for studying how population properties such as age structure relate to environmental influences on recruitment and mortality. We investigated population dynamics of the freshwater pearl mussel, Margaritifera falcata, in 2 northern California Coast Range rivers, the South Fork Eel and the Navarro. We used field observations and inverse theoretical modeling to assess age structures and identify factors that control population demographics. Distinctly different mortality rates for young (<20 y) and old (≥20 y) mussels were observed in the South Fork Eel, and recruitment and mortality both were related to river discharge regimes. Margaritifera falcata recruited more successfully during low-discharge than during high-discharge years, and a 2-fold increase in discharge caused a 60% decline in recruitment success. Active annual recruitment (˜1100–1800 ind./y) was observed in the South Fork Eel, whereas recruitment has been low or nonexistent during the past 30 y in the Navarro. This difference probably is a consequence of the influence of 2 non-mutually exclusive factors: landuse history and host-fish abundance. The Navarro watershed has extensive timber harvesting and orchard/vineyard agriculture and has had severe declines in fish populations, whereas large sections of the South Fork Eel pass through protected land and the river has retained its historical fish populations. Investigation of the factors that shape local M. falcata population age structures yielded insights into the influence of environmental variables and history on mortality and recruitment that will aid conservation of this endangered family.
2005
Howard, J. K.; Cuffey, K. M.; Solomon, M.
In: Hydrobiologia, vol. 541, no. 1, pp. 229-236, 2005.
Abstract | Links | BibTeX | Tags: baseline conditions, California, freshwater mussels, stable isotope, trophic
@article{Howard2005,
title = {Toward using Margariitifera falcate as an indicator of base level nitrogen and carbon isotope ratios: insights from two California Coast Range rivers},
author = {J. K. Howard and K. M. Cuffey and M. Solomon},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Howard_2005_Hydrobio.pdf},
doi = {10.1007/s10750-004-5711-4},
year = {2005},
date = {2005-06-01},
journal = {Hydrobiologia},
volume = {541},
number = {1},
pages = {229-236},
abstract = {Measurements of freshwater mussel tissue are potentially very useful for determining base-level isotopic values for food web studies in aquatic environments. As long-lived, filter-feeding organisms, mussels have the potential to spatially and temporally average the isotopic baseline signal. Following from earlier studies that focused on lake environments, this study investigates the stable carbon and nitrogen isotope ratios in tissue of the river dwelling freshwater mussel, Margaritifera falcata, in two extensively studied northern California coast range rivers, the South Fork Eel and Navarro. We highlight advantages and challenges for using riverine mussel isotopes as indicators of baselines. δ13C of primary producers is known to vary with habitat along the South Fork Eel channel, but our measurements show no such variations, demonstrating that riverine mussels do preserve a spatially averaged measure of instream derived food sources. Mean δ13C and δ15N are shown to be markedly different in the two rivers, reflecting differences in food sources and possibly watershed land use. We also found that δ15N of mussel tissue increased by approximately 2‰ with mussel age in both rivers. This suggests it is important to consider age and size effects when estimating baseline values from mussel tissues.},
keywords = {baseline conditions, California, freshwater mussels, stable isotope, trophic},
pubstate = {published},
tppubtype = {article}
}
Measurements of freshwater mussel tissue are potentially very useful for determining base-level isotopic values for food web studies in aquatic environments. As long-lived, filter-feeding organisms, mussels have the potential to spatially and temporally average the isotopic baseline signal. Following from earlier studies that focused on lake environments, this study investigates the stable carbon and nitrogen isotope ratios in tissue of the river dwelling freshwater mussel, Margaritifera falcata, in two extensively studied northern California coast range rivers, the South Fork Eel and Navarro. We highlight advantages and challenges for using riverine mussel isotopes as indicators of baselines. δ13C of primary producers is known to vary with habitat along the South Fork Eel channel, but our measurements show no such variations, demonstrating that riverine mussels do preserve a spatially averaged measure of instream derived food sources. Mean δ13C and δ15N are shown to be markedly different in the two rivers, reflecting differences in food sources and possibly watershed land use. We also found that δ15N of mussel tissue increased by approximately 2‰ with mussel age in both rivers. This suggests it is important to consider age and size effects when estimating baseline values from mussel tissues.
2004
Eisen, Rebecca J.; Eisen, Lars; Lane, Robert S.
Habitat-related variation in infestation of lizards and rodents with Ixodes ticks in dense woodlands Journal Article
In: Experimental and Applied Acarology, vol. 33, no. 3, pp. 215-233, 2004, ISSN: 1572-9702.
Abstract | Links | BibTeX | Tags: Borrelia burgdorferi, California, Infestation, Ixodes pacificus, Lizards, Rodents
@article{Eisen2004,
title = {Habitat-related variation in infestation of lizards and rodents with Ixodes ticks in dense woodlands},
author = {Rebecca J. Eisen and Lars Eisen and Robert S. Lane},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Habitat-related-variation-in-infestation-of-lizards-and-rodents-with-Ixodes-ticks-in-dense-woodlands-in-Mendocino-County-California_Eisen.pdf},
doi = {10.1023/B:APPA.0000032954.71165.9e},
issn = {1572-9702},
year = {2004},
date = {2004-07-01},
journal = {Experimental and Applied Acarology},
volume = {33},
number = {3},
pages = {215-233},
abstract = {During the spring and early summer of 2002, we examined the relative importance of Borrelia-refractory lizards (Sceloporus occidentalis, Elgaria spp.) versus potential Borrelia burgdorferi sensu lato (s.l.)-reservoirs (rodents) as hosts for Ixodes pacificus immatures in 14 woodland areas (six oak, five mixed oak/Douglas fir, and three redwood/tanoak areas) distributed throughout Mendocino County, California. Lizards were estimated to serve as hosts for 93–98% of all larvae and ≥99.6% of all nymphs infesting lizards or rodents in oak woodlands and oak/Douglas fir sites in the southern part of the county. In redwood/tanoak woodlands and oak/Douglas fir sites in northern Mendocino County, the contribution of rodents to larval feedings reached 36–69% but lizards still accounted for 94–100% of nymphal bloodmeals. From late April to mid-June, I. pacificus larvae were recovered from 95 to 96% of lizards and dusky-footed woodrats (Neotoma fuscipes) and from 59% of Peromyscus spp. mice. In contrast, 99% of lizards but few woodrats (15%) and none of the mice were infested by nymphs. Comparisons of tick loads for 19 lizard–Peromyscus spp. mouse pairings, where the lizard and mouse were captured within 10 m of each other, revealed that the lizards harbored 36 times more larvae and >190 times more nymphs than the mice. In oak woodlands, loads of I. pacificus larvae decreased from late April/early May to late June for S. occidentalis lizards but increased for Peromyscus spp. mice. We conclude that the relative utilization of Borrelia-refractory lizards, as compared to rodents, by I. pacificus larvae was far higher in dry oak woodlands than in moister habitats such as redwood/tanoak and oak/Douglas fir woodlands in northern Mendocino County. Non-lizard-infesting potential enzootic vectors of B. burgdorferi s.l. (I. angustus and I. spinipalpis) were recorded from rodents in three of six oak woodland areas, two of five oak/Douglas fir woodland areas, and two of three redwood/tanoak woodland areas.},
keywords = {Borrelia burgdorferi, California, Infestation, Ixodes pacificus, Lizards, Rodents},
pubstate = {published},
tppubtype = {article}
}
During the spring and early summer of 2002, we examined the relative importance of Borrelia-refractory lizards (Sceloporus occidentalis, Elgaria spp.) versus potential Borrelia burgdorferi sensu lato (s.l.)-reservoirs (rodents) as hosts for Ixodes pacificus immatures in 14 woodland areas (six oak, five mixed oak/Douglas fir, and three redwood/tanoak areas) distributed throughout Mendocino County, California. Lizards were estimated to serve as hosts for 93–98% of all larvae and ≥99.6% of all nymphs infesting lizards or rodents in oak woodlands and oak/Douglas fir sites in the southern part of the county. In redwood/tanoak woodlands and oak/Douglas fir sites in northern Mendocino County, the contribution of rodents to larval feedings reached 36–69% but lizards still accounted for 94–100% of nymphal bloodmeals. From late April to mid-June, I. pacificus larvae were recovered from 95 to 96% of lizards and dusky-footed woodrats (Neotoma fuscipes) and from 59% of Peromyscus spp. mice. In contrast, 99% of lizards but few woodrats (15%) and none of the mice were infested by nymphs. Comparisons of tick loads for 19 lizard–Peromyscus spp. mouse pairings, where the lizard and mouse were captured within 10 m of each other, revealed that the lizards harbored 36 times more larvae and >190 times more nymphs than the mice. In oak woodlands, loads of I. pacificus larvae decreased from late April/early May to late June for S. occidentalis lizards but increased for Peromyscus spp. mice. We conclude that the relative utilization of Borrelia-refractory lizards, as compared to rodents, by I. pacificus larvae was far higher in dry oak woodlands than in moister habitats such as redwood/tanoak and oak/Douglas fir woodlands in northern Mendocino County. Non-lizard-infesting potential enzootic vectors of B. burgdorferi s.l. (I. angustus and I. spinipalpis) were recorded from rodents in three of six oak woodland areas, two of five oak/Douglas fir woodland areas, and two of three redwood/tanoak woodland areas.
2003
Howard, Jeanette K.; Cuffey, Kurt M.
Freshwater mussels in a California North Coast Range river: occurrence, distribution, and controls Journal Article
In: Journal of the North American Benthological Society, vol. 22, no. 1, pp. 63-77, 2003.
Abstract | Links | BibTeX | Tags: California, freshwater mussels, geomorphology, hydraulic model, hydrology, microhabitat, shear stress, South Fork Eel River
@article{Howard2003,
title = {Freshwater mussels in a California North Coast Range river: occurrence, distribution, and controls},
author = {Jeanette K. Howard and Kurt M. Cuffey},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Howard_2003_JouNorthAmerBenthoSoc.pdf},
doi = {10.2307/1467978},
year = {2003},
date = {2003-03-01},
journal = {Journal of the North American Benthological Society},
volume = {22},
number = {1},
pages = {63-77},
abstract = {We report the occurrence and habitat of mussel populations within a continuous 8-km section of the South Fork Eel River in the Northern Coast Range of California. The primary goals of our study were 1) to compile information on species composition and population density, and 2) to examine whether spatial distribution and variability were related to geomorphology and hydrology. High discharges almost certainly provide more of a constraint on the distribution and persistence of
mussels in the South Fork Eel than do low summer flows, so we used the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) hydraulic model to estimate physical conditions during high flows when in-channel investigations were not feasible. We found numerous individuals of 2 species (Margaritifera falcata and Anodonta californiensis), with the spatial distribution of both species
characterized by high variability. Mussels in this system live almost exclusively in pools (with a few in runs), near the channel banks, and especially among sedge root-mat substrate. In all flow regimes (summer, winter, 5-y flood, and the largest floods on record), we found mussels in areas of lower boundary shear stresses and lower velocities. Our study suggests that, at various spatial scales, mussels appear to be distributed in a manner that protects them from the highest flow-induced stresses.},
keywords = {California, freshwater mussels, geomorphology, hydraulic model, hydrology, microhabitat, shear stress, South Fork Eel River},
pubstate = {published},
tppubtype = {article}
}
We report the occurrence and habitat of mussel populations within a continuous 8-km section of the South Fork Eel River in the Northern Coast Range of California. The primary goals of our study were 1) to compile information on species composition and population density, and 2) to examine whether spatial distribution and variability were related to geomorphology and hydrology. High discharges almost certainly provide more of a constraint on the distribution and persistence of
mussels in the South Fork Eel than do low summer flows, so we used the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) hydraulic model to estimate physical conditions during high flows when in-channel investigations were not feasible. We found numerous individuals of 2 species (Margaritifera falcata and Anodonta californiensis), with the spatial distribution of both species
characterized by high variability. Mussels in this system live almost exclusively in pools (with a few in runs), near the channel banks, and especially among sedge root-mat substrate. In all flow regimes (summer, winter, 5-y flood, and the largest floods on record), we found mussels in areas of lower boundary shear stresses and lower velocities. Our study suggests that, at various spatial scales, mussels appear to be distributed in a manner that protects them from the highest flow-induced stresses.
mussels in the South Fork Eel than do low summer flows, so we used the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) hydraulic model to estimate physical conditions during high flows when in-channel investigations were not feasible. We found numerous individuals of 2 species (Margaritifera falcata and Anodonta californiensis), with the spatial distribution of both species
characterized by high variability. Mussels in this system live almost exclusively in pools (with a few in runs), near the channel banks, and especially among sedge root-mat substrate. In all flow regimes (summer, winter, 5-y flood, and the largest floods on record), we found mussels in areas of lower boundary shear stresses and lower velocities. Our study suggests that, at various spatial scales, mussels appear to be distributed in a manner that protects them from the highest flow-induced stresses.
1999
Levine, Jonathan M.; D’Antonio, Carla M.
Elton revisited: a review of evidence linking diversity and invasibility Journal Article
In: Oikos, vol. 87, no. 1, pp. 15-26, 1999, ISSN: 0030-1299, (File size exceeds maximum allowable for Angelo’s website. Please see the attached stable link for PDF.).
Abstract | Links | BibTeX | Tags: biodiversity, biological invasions, California, COMMUNITIES, competition, exotic plants, grassland, introduced Hawaiian avifauna, New Zealand, positive interactions, riparian zones
@article{Levine1999,
title = {Elton revisited: a review of evidence linking diversity and invasibility},
author = {Jonathan M. Levine and Carla M. D'Antonio},
url = {http://www.jstor.org/stable/3546992},
doi = {10.2307/3546992},
issn = {0030-1299},
year = {1999},
date = {1999-10-00},
journal = {Oikos},
volume = {87},
number = {1},
pages = {15-26},
abstract = {It is commonly believed that diverse communities better resist invasion by exotic species than do simple communities. We examined the history of this notion, and evaluated theoretical and empirical work linking diversity and invasions. We found that much of the historical work that has contributed to the perception that diverse communities are less invasible, including Elton's observations and MacArthur's species-packing and diversity-stability models, is based on controversial premises. Nevertheless, more recent theoretical studies consistently supported the predicted negative relationship between diversity and invasibility. The results of empirical studies, however, were decidedly mixed. Constructed community studies directly manipulating diversity found both positive and negative effects of diversity on invasibility in both field and microcosm settings. Other empirical studies tracking the assembly of ecological communities generally suggested that communities decline in invasibility as species accumulate over time, though the role of diversity itself was often ambiguous. Studies of the spatial correlation between diversity and invasion and studies experimentally adding invaders to natural systems indicated that diverse communities tend to be more invasible. We argue that these results most likely reflect environmental factors spatially covarying with diversity in natural communities (e.g. resources, disturbance), and not the effects of diversity itself as uncovered by constructed community studies. Nevertheless, the consistent positive relationship between exotic species abundance and resident species diversity found in spatial pattern studies suggests that invaders and resident species are more similar than often believed, and the implications of this for theories of invasion are discussed.},
note = {File size exceeds maximum allowable for Angelo's website. Please see the attached stable link for PDF.},
keywords = {biodiversity, biological invasions, California, COMMUNITIES, competition, exotic plants, grassland, introduced Hawaiian avifauna, New Zealand, positive interactions, riparian zones},
pubstate = {published},
tppubtype = {article}
}
It is commonly believed that diverse communities better resist invasion by exotic species than do simple communities. We examined the history of this notion, and evaluated theoretical and empirical work linking diversity and invasions. We found that much of the historical work that has contributed to the perception that diverse communities are less invasible, including Elton’s observations and MacArthur’s species-packing and diversity-stability models, is based on controversial premises. Nevertheless, more recent theoretical studies consistently supported the predicted negative relationship between diversity and invasibility. The results of empirical studies, however, were decidedly mixed. Constructed community studies directly manipulating diversity found both positive and negative effects of diversity on invasibility in both field and microcosm settings. Other empirical studies tracking the assembly of ecological communities generally suggested that communities decline in invasibility as species accumulate over time, though the role of diversity itself was often ambiguous. Studies of the spatial correlation between diversity and invasion and studies experimentally adding invaders to natural systems indicated that diverse communities tend to be more invasible. We argue that these results most likely reflect environmental factors spatially covarying with diversity in natural communities (e.g. resources, disturbance), and not the effects of diversity itself as uncovered by constructed community studies. Nevertheless, the consistent positive relationship between exotic species abundance and resident species diversity found in spatial pattern studies suggests that invaders and resident species are more similar than often believed, and the implications of this for theories of invasion are discussed.
1997
Kupferberg, Sarah J.
Bullfrog (Rana catesbeiana) invasion of a California river: the role of larval competition Journal Article
In: Ecology, vol. 78, no. 6, pp. 1736-1751, 1997, ISSN: 0012-9658.
Abstract | Links | BibTeX | Tags: algae, biological invasions, California, grazing, Hyla regilla, Rana boylii, Rana catesbeiana, rivers, size-structured competition
@article{Kupferberg1997,
title = {Bullfrog (Rana catesbeiana) invasion of a California river: the role of larval competition},
author = {Sarah J. Kupferberg},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Kupferberg_Ecology1997.pdf},
issn = {0012-9658},
year = {1997},
date = {1997-09-00},
journal = {Ecology},
volume = {78},
number = {6},
pages = {1736-1751},
abstract = {I studied the invasion of Rana catesbeiana (the bullfrog) into a northern California river system where bullfrogs are not native. Native yellow-legged frogs, Rana boylii, a species of special concern, were almost an order of magnitude less abundant in reaches where bullfrogs were well established. I assessed the potential role of larval competition in contributing to this displacement in a series of field manipulations of tadpole density and species composition. The impact of R. catesbeiana on native tadpoles in the natural community agreed with the outcome of more artificial experiments testing pairwise and three-way interactions. In 2-m(2) enclosures with ambient densities of tadpoles and natural river biota, bullfrog tadpoles caused a 48% reduction in survivorship of R. boylii, and a 24% decline in mass at metamorphosis. Bullfrog larvae had smaller impacts on Pacific treefrogs, Hyla regilla, causing 16% reduction in metamorph size, and no significant effect on survivorship. Bullfrog tadpoles significantly affected benthic algae, although effects varied across sites. Responses to bullfrogs in field settings were similar qualitatively to results seen in smaller-scale experiments designed to study size-structured competition among disparate age/size classes of species pairs and trios. Competition from large overwintering bullfrog larvae significantly decreased survivorship and growth of native tadpoles. Competition from recently hatched bullfrog larvae also decreased survivorship of R. boylii and H. regilla. Native species competed weakly, both interspecifically and intraspecifically. The only suggestion of a negative impact of a native species on bullfrogs was a weak effect of H. regilla on recent hatchlings. Competition appeared to be mediated by algal resources, and there was no evidence for behavioral or chemical interference. These results indicate that, through larval interactions, bullfrogs can exert differential effects on native frogs and perturb aquatic community structure.},
keywords = {algae, biological invasions, California, grazing, Hyla regilla, Rana boylii, Rana catesbeiana, rivers, size-structured competition},
pubstate = {published},
tppubtype = {article}
}
I studied the invasion of Rana catesbeiana (the bullfrog) into a northern California river system where bullfrogs are not native. Native yellow-legged frogs, Rana boylii, a species of special concern, were almost an order of magnitude less abundant in reaches where bullfrogs were well established. I assessed the potential role of larval competition in contributing to this displacement in a series of field manipulations of tadpole density and species composition. The impact of R. catesbeiana on native tadpoles in the natural community agreed with the outcome of more artificial experiments testing pairwise and three-way interactions. In 2-m(2) enclosures with ambient densities of tadpoles and natural river biota, bullfrog tadpoles caused a 48% reduction in survivorship of R. boylii, and a 24% decline in mass at metamorphosis. Bullfrog larvae had smaller impacts on Pacific treefrogs, Hyla regilla, causing 16% reduction in metamorph size, and no significant effect on survivorship. Bullfrog tadpoles significantly affected benthic algae, although effects varied across sites. Responses to bullfrogs in field settings were similar qualitatively to results seen in smaller-scale experiments designed to study size-structured competition among disparate age/size classes of species pairs and trios. Competition from large overwintering bullfrog larvae significantly decreased survivorship and growth of native tadpoles. Competition from recently hatched bullfrog larvae also decreased survivorship of R. boylii and H. regilla. Native species competed weakly, both interspecifically and intraspecifically. The only suggestion of a negative impact of a native species on bullfrogs was a weak effect of H. regilla on recent hatchlings. Competition appeared to be mediated by algal resources, and there was no evidence for behavioral or chemical interference. These results indicate that, through larval interactions, bullfrogs can exert differential effects on native frogs and perturb aquatic community structure.