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2020 |
Uno, Hiromi; Pneh, Shelley Ecological Research, 35 (3), pp. 474-481, 2020. Abstract | Links | BibTeX | Tags: diversity, ecological function, predator-prey dynamics, Riparian, STREAM @article{Uno2020b, title = {Effect of source habitat spatial heterogeneity and species diversity on the temporal stability of aquatic‐to‐terrestrial subsidy by emerging aquatic insects}, author = {Hiromi Uno and Shelley Pneh}, doi = {10.1111/1440-1703.12125}, year = {2020}, date = {2020-05-25}, journal = {Ecological Research}, volume = {35}, number = {3}, pages = {474-481}, abstract = {Duration and temporal stability of resource subsidy largely affect the response of recipient communities. Factors that influence the temporal dynamics of resource subsidy from aquatic‐to‐terrestrial habitats by emerging aquatic insects were examined in this study. By measuring the flux of aquatic insect emergence from six habitats in a river over summer, we found that the timing of emergence varied by habitats for each dominant taxa, and that different species emerged at different times of the summer sequentially. We found that spatial variation in the emergence timing caused by the spatial heterogeneity of the water temperature, and so on in the source habitat can temporally stabilize the subsidy of each species from the whole river. Similarly, we found that the variation in emergence timing between species contributed to the temporal stability of subsidies from each habitat. The contribution of spatial heterogeneity to the temporal stability varied by the focal species and the contribution of species diversity varied by habitats. This study demonstrates how the ecological function of spatial heterogeneity and species diversity crosses the boundary of ecosystems by temporally stabilizing resource subsidies.}, keywords = {diversity, ecological function, predator-prey dynamics, Riparian, STREAM}, pubstate = {published}, tppubtype = {article} } Duration and temporal stability of resource subsidy largely affect the response of recipient communities. Factors that influence the temporal dynamics of resource subsidy from aquatic‐to‐terrestrial habitats by emerging aquatic insects were examined in this study. By measuring the flux of aquatic insect emergence from six habitats in a river over summer, we found that the timing of emergence varied by habitats for each dominant taxa, and that different species emerged at different times of the summer sequentially. We found that spatial variation in the emergence timing caused by the spatial heterogeneity of the water temperature, and so on in the source habitat can temporally stabilize the subsidy of each species from the whole river. Similarly, we found that the variation in emergence timing between species contributed to the temporal stability of subsidies from each habitat. The contribution of spatial heterogeneity to the temporal stability varied by the focal species and the contribution of species diversity varied by habitats. This study demonstrates how the ecological function of spatial heterogeneity and species diversity crosses the boundary of ecosystems by temporally stabilizing resource subsidies. |
Uno, Hiromi; Stillman, Jonathon H Lifetime eurythermy by seasonally matched thermal performance of developmental stages in an annual aquatic insect Journal Article Oecologia, 192 (3), pp. 647-656, 2020. Abstract | Links | BibTeX | Tags: Aquatic insect, life cycle, season, STREAM, temperature @article{Uno2020, title = {Lifetime eurythermy by seasonally matched thermal performance of developmental stages in an annual aquatic insect}, author = {Hiromi Uno and Jonathon H. Stillman}, url = {https://angelo.berkeley.edu/oecologia-2020-uno/}, doi = {10.1007/s00442-020-04605-z}, year = {2020}, date = {2020-01-27}, journal = {Oecologia}, volume = {192}, number = {3}, pages = {647-656}, abstract = {Organisms with annual life cycles are exposed to life stage specific thermal environments across seasons. Seasonal variation in thermal environments can vary across years and among sites. We investigated how organisms with annual life cycles respond to predictable seasonal changes in temperature and unpredictable thermal variation between habitats and years throughout their lives. Field surveys and historical records reveal that the spatially and temporally heterogeneous thermal environments inhabited by the annual mayfly Ephemerella maculata (Ephemerellidae) shift the date for transition to the next, life stage, so that the thermal phenotype of each life stage matches the thermal environment of the specific habitat and year. Laboratory studies of three distinct life stages of this mayfly reveal that life stage transitions are temperature dependent, facilitating timing shifts that are synchronized with the current season’s temperatures. Each life stage exhibited specific thermal sensitivity and performance phenotypes that matched the ambient temperature typically experienced during that life stage. Our study across the whole life cycle reveals mechanisms that allow organisms to achieve lifetime eurythermy in a dynamic seasonal environment, despite having narrower thermal ranges for growth and development in each life stage.}, keywords = {Aquatic insect, life cycle, season, STREAM, temperature}, pubstate = {published}, tppubtype = {article} } Organisms with annual life cycles are exposed to life stage specific thermal environments across seasons. Seasonal variation in thermal environments can vary across years and among sites. We investigated how organisms with annual life cycles respond to predictable seasonal changes in temperature and unpredictable thermal variation between habitats and years throughout their lives. Field surveys and historical records reveal that the spatially and temporally heterogeneous thermal environments inhabited by the annual mayfly Ephemerella maculata (Ephemerellidae) shift the date for transition to the next, life stage, so that the thermal phenotype of each life stage matches the thermal environment of the specific habitat and year. Laboratory studies of three distinct life stages of this mayfly reveal that life stage transitions are temperature dependent, facilitating timing shifts that are synchronized with the current season’s temperatures. Each life stage exhibited specific thermal sensitivity and performance phenotypes that matched the ambient temperature typically experienced during that life stage. Our study across the whole life cycle reveals mechanisms that allow organisms to achieve lifetime eurythermy in a dynamic seasonal environment, despite having narrower thermal ranges for growth and development in each life stage. |
2002 |
Sabo, John L; Power, Mary E River-watershed exchange: Effects of riverine subsidies on riparian lizards and their terrestrial prey Journal Article Ecology, 83 (7), pp. 1860-1869, 2002, ISSN: 0012-9658. Abstract | Links | BibTeX | Tags: APPARENT COMPETITION, AQUATIC INSECTS, BENTHIC-PELAGIC LINKS, COMMUNITIES, FOOD-WEB, invertebrates, ISLANDS, MARINE, SECONDARY PRODUCTION, STREAM @article{Sabo2002, title = {River-watershed exchange: Effects of riverine subsidies on riparian lizards and their terrestrial prey}, author = {John L. Sabo and Mary E. Power}, url = {https://angelo.berkeley.edu/wp-content/uploads/River-watershed-exchange-Effects-of-riverine-subsidies-on-riparian-lizards-and-their-terrestrial-prey_Sabo_2002.pdf}, issn = {0012-9658}, year = {2002}, date = {2002-07-00}, journal = {Ecology}, volume = {83}, number = {7}, pages = {1860-1869}, abstract = {Resource subsidies from external habitats can enhance the performance or population density of local consumers, altering their effects on in situ prey. Indirect effects of subsidies may be either positive or negative depending on the behavior of the shared consumer. Here we document strong links between riverine insects, riparian lizards (Sceloporus occidentalis), and terrestrial invertebrates. We hypothesized that aquatic insects subsidize riparian lizard populations leading to higher growth rates of these lizards in near-river habitats, and that subsidies exert short-term positive effects on terrestrial resources as a result of diet shifts by lizards to aquatic insects. To test these hypotheses, we used 2 m high fences, or "subsidy shields," to experimentally reduce aquatic insect flux to large (91 m 2) enclosures of lizards. Subsidy shields reduced aquatic insect flux by 55-65%. Growth rates of lizards were 7X higher in subsidized (no-shield) enclosures during the early summer but were not significantly different later in the summer, when ambient fluxes of aquatic insects dropped to 20% of their early season levels. Within the watershed, lizard growth rates (in mass) were positively correlated with the numerical abundance of aquatic insects. Thus, lizard growth rates tracked both seasonal and spatial availability of riverine insect subsidies during our experiment. Subsidies also had indirect effects on the ground-dwelling, terrestrial prey of lizards. Declines of diurnal terrestrial invertebrates Were significantly higher in shield than no-shield enclosures, and the most common ground spider (Arctosa sp. [Lycosidae]) disappeared completely from shield enclosures by the end of the experiment. Declines in terrestrial invertebrate abundance did not differ between no-shield enclosures and lizard exclosures. These data suggest that riverine insects subsidize riparian Sceloporus and, in the short term, reduce their predation on terrestrial arthropods.}, keywords = {APPARENT COMPETITION, AQUATIC INSECTS, BENTHIC-PELAGIC LINKS, COMMUNITIES, FOOD-WEB, invertebrates, ISLANDS, MARINE, SECONDARY PRODUCTION, STREAM}, pubstate = {published}, tppubtype = {article} } Resource subsidies from external habitats can enhance the performance or population density of local consumers, altering their effects on in situ prey. Indirect effects of subsidies may be either positive or negative depending on the behavior of the shared consumer. Here we document strong links between riverine insects, riparian lizards (Sceloporus occidentalis), and terrestrial invertebrates. We hypothesized that aquatic insects subsidize riparian lizard populations leading to higher growth rates of these lizards in near-river habitats, and that subsidies exert short-term positive effects on terrestrial resources as a result of diet shifts by lizards to aquatic insects. To test these hypotheses, we used 2 m high fences, or "subsidy shields," to experimentally reduce aquatic insect flux to large (91 m 2) enclosures of lizards. Subsidy shields reduced aquatic insect flux by 55-65%. Growth rates of lizards were 7X higher in subsidized (no-shield) enclosures during the early summer but were not significantly different later in the summer, when ambient fluxes of aquatic insects dropped to 20% of their early season levels. Within the watershed, lizard growth rates (in mass) were positively correlated with the numerical abundance of aquatic insects. Thus, lizard growth rates tracked both seasonal and spatial availability of riverine insect subsidies during our experiment. Subsidies also had indirect effects on the ground-dwelling, terrestrial prey of lizards. Declines of diurnal terrestrial invertebrates Were significantly higher in shield than no-shield enclosures, and the most common ground spider (Arctosa sp. [Lycosidae]) disappeared completely from shield enclosures by the end of the experiment. Declines in terrestrial invertebrate abundance did not differ between no-shield enclosures and lizard exclosures. These data suggest that riverine insects subsidize riparian Sceloporus and, in the short term, reduce their predation on terrestrial arthropods. |
1997 |
Gresens, Susan E Interactive effects of diet and thermal regime on growth of the midge Pseudochironomus richardsoni Malloch Journal Article Freshwater Biology, 38 (2), pp. 365-373, 1997, ISSN: 0046-5070. Abstract | Links | BibTeX | Tags: Blackwater River, diptera, larval chironomidae, rapid growth, Riparian, river food webs, SECONDARY PRODUCTION, size, STREAM, temperature @article{Gresens1997, title = {Interactive effects of diet and thermal regime on growth of the midge Pseudochironomus richardsoni Malloch}, author = {Susan E. Gresens}, url = {https://angelo.berkeley.edu/wp-content/uploads/Gresens_FreshwaterBiology1997.pdf}, doi = {10.1046/j.1365-2427.1997.00248.x}, issn = {0046-5070}, year = {1997}, date = {1997-10-00}, journal = {Freshwater Biology}, volume = {38}, number = {2}, pages = {365-373}, abstract = {1. Larvae of Pseudochironomus richardsoni were reared to pupation in individual enclosures, in one of three thermal habitats in a northern California stream. The average temperature range in cold seeps was 15-21 degrees C, while the main channel ranged from 20 to 27 degrees C, and side pools ranged from 18 to 33 degrees C. Diet consisted of either diatoms or algal detritus. 2. Specific growth rate ranged from 0.057 to 0.267 day(-1). Specific growth and developmental rates were highest on a diatom diet, and increased with temperature. Regressions of growth rate on mean microsite temperature were also significantly altered by diet. Differences in specific growth rate due to diet are magnified at higher temperatures. 3. Pupae reared on diatoms were larger than those reared on detritus. The mass of pupae reared on detritus decreased with increasing temperature. However, there was no significant relationship between pupal mass and temperature for larvae reared on diatoms. 4. The combined effects of food quality and thermal environment on growth of the midge P. richardsoni are significantly different from the independent effects of diet and temperature. Interactive effects of food quality and temperature may influence the contribution of certain aquatic habitats (algal mats) to invertebrate secondary production.}, keywords = {Blackwater River, diptera, larval chironomidae, rapid growth, Riparian, river food webs, SECONDARY PRODUCTION, size, STREAM, temperature}, pubstate = {published}, tppubtype = {article} } 1. Larvae of Pseudochironomus richardsoni were reared to pupation in individual enclosures, in one of three thermal habitats in a northern California stream. The average temperature range in cold seeps was 15-21 degrees C, while the main channel ranged from 20 to 27 degrees C, and side pools ranged from 18 to 33 degrees C. Diet consisted of either diatoms or algal detritus. 2. Specific growth rate ranged from 0.057 to 0.267 day(-1). Specific growth and developmental rates were highest on a diatom diet, and increased with temperature. Regressions of growth rate on mean microsite temperature were also significantly altered by diet. Differences in specific growth rate due to diet are magnified at higher temperatures. 3. Pupae reared on diatoms were larger than those reared on detritus. The mass of pupae reared on detritus decreased with increasing temperature. However, there was no significant relationship between pupal mass and temperature for larvae reared on diatoms. 4. The combined effects of food quality and thermal environment on growth of the midge P. richardsoni are significantly different from the independent effects of diet and temperature. Interactive effects of food quality and temperature may influence the contribution of certain aquatic habitats (algal mats) to invertebrate secondary production. |
1995 |
Power, Mary E; Sun, Adrian; Parker, Gary; Dietrich, William E; Wootton, Timothy J Hydraulic food chain models Journal Article BioScience, 45 (3), pp. 159-167, 1995, (See stable URL attached; file size exceeds maximum allowable for Angelo.). Links | BibTeX | Tags: consequences, dynamics, ecosystems, food webs, hetergeneity, patterns, productivity, Southern Ontario, STREAM, top-down @article{Power1995b, title = {Hydraulic food chain models}, author = {Mary E. Power and Adrian Sun and Gary Parker and William E. Dietrich and J. Timothy Wootton}, url = {http://www.jstor.org/stable/1312555}, doi = {10.2307/1312555}, year = {1995}, date = {1995-03-00}, journal = {BioScience}, volume = {45}, number = {3}, pages = {159-167}, note = {See stable URL attached; file size exceeds maximum allowable for Angelo.}, keywords = {consequences, dynamics, ecosystems, food webs, hetergeneity, patterns, productivity, Southern Ontario, STREAM, top-down}, pubstate = {published}, tppubtype = {article} } |