Beskrivning: Klimatförändringar och beteendekaskaders betydelse för klarvattenfasen i sjöar. Sjöa... more Beskrivning: Klimatförändringar och beteendekaskaders betydelse för klarvattenfasen i sjöar. Sjöar med riklig förekomst av undervattenväxter anses ha ett högt naturvärde. De har klart vatten samt rikligt med sjöfågel och rovfiskar. I vegetationsrika sjöar finns under sommaren många olika miljöer för bl. a. småfisk, djurplankton och olika insekter att gömma sig eller söka föda i. Under vintern, när aktiviteten är låg hos många djur, försvinner många vattenväxter för att återkomma igen till våren.
Abstract The impact of young-of-the-year (YOY) fish predation on zooplankton dynamics and cascadi... more Abstract The impact of young-of-the-year (YOY) fish predation on zooplankton dynamics and cascading effects down to phytoplankton were studied in lake enclosures using different densities of larval and juvenile European perch (Perca fluviatilis). Two experiments, one in June and one in August, were performed in Lake Dagstorpssjön, a slightly eutrophic lake in Scania, southern Sweden.
SUMMARY 1. We performed both a large-and a small-scale echo sounding study on the spatial and tem... more SUMMARY 1. We performed both a large-and a small-scale echo sounding study on the spatial and temporal distribution of fish (mainly roach, Rutilus rutilus and perch, Perca fluviatlis), as well as a small-scale study of zooplankton distribution in the small, shallow and eutrophic Lake Hanebjerg in Denmark. In the small-scale study, sampling was conducted in open water as well as in the edge zone immediately outside two different types of vegetation. 2.
Abstract: Simple models, based on Lotka-Volterra types of interactions between predator and prey,... more Abstract: Simple models, based on Lotka-Volterra types of interactions between predator and prey, predict that enrichment will have a destabilizing effect on populations and that equilibrium population densities will change at the top trophic level and every second level below. We experimentally tested these predictions in three aquatic food web configurations subjected to either high or low nutrient additions.
It is well known that the effects of direct (lethal) predator-prey interactions propagate through... more It is well known that the effects of direct (lethal) predator-prey interactions propagate through food webs (the trophic cascade). However, in the present study we show for the first time that, parallel to the trophic cascade, there exists a" behavioral cascade" in the sense that behavioral responses, induced by the nonlethal presence of a top predator, are transmitted down the food chain over more than one trophic link.
Abstract In Lake Washington, juvenile sockeye salmon (Oncorhynchus nerka) strongly prefer Daphnia... more Abstract In Lake Washington, juvenile sockeye salmon (Oncorhynchus nerka) strongly prefer Daphnia over other prey, switching uniformly to Daphnia when the threshold abundance of 0.4 Daphnia L− 1 is achieved.
In order to disentangle if and when resource supply and adult and young-of-the-year (0+) fish pre... more In order to disentangle if and when resource supply and adult and young-of-the-year (0+) fish predation affect zooplankton dynamics during spring, we monitored zooplankton during three consecutive years in a lake in southern Sweden. We also experimentally assessed 0+ fish predation rates and estimated changes in predation rates of adult fish on zooplankton. Decline in abundances of large-sized zooplankters in early spring was not caused by 0+ fish predation.
Abstract The interactions between consumers and prey, and their impact on biomass distribution am... more Abstract The interactions between consumers and prey, and their impact on biomass distribution among trophic levels, are central issues in both empirical and theoretical ecology. In a long–term experiment, where all organisms, including the top predator, were allowed to respond to environmental conditions by reproduction, we tested predictions from 'prey–dependent'and 'ratio–dependent'models.
Beskrivning: Klimatförändringar och beteendekaskaders betydelse för klarvattenfasen i sjöar. Sjöa... more Beskrivning: Klimatförändringar och beteendekaskaders betydelse för klarvattenfasen i sjöar. Sjöar med riklig förekomst av undervattenväxter anses ha ett högt naturvärde. De har klart vatten samt rikligt med sjöfågel och rovfiskar. I vegetationsrika sjöar finns under sommaren många olika miljöer för bl. a. småfisk, djurplankton och olika insekter att gömma sig eller söka föda i. Under vintern, när aktiviteten är låg hos många djur, försvinner många vattenväxter för att återkomma igen till våren.
Abstract The impact of young-of-the-year (YOY) fish predation on zooplankton dynamics and cascadi... more Abstract The impact of young-of-the-year (YOY) fish predation on zooplankton dynamics and cascading effects down to phytoplankton were studied in lake enclosures using different densities of larval and juvenile European perch (Perca fluviatilis). Two experiments, one in June and one in August, were performed in Lake Dagstorpssjön, a slightly eutrophic lake in Scania, southern Sweden.
SUMMARY 1. We performed both a large-and a small-scale echo sounding study on the spatial and tem... more SUMMARY 1. We performed both a large-and a small-scale echo sounding study on the spatial and temporal distribution of fish (mainly roach, Rutilus rutilus and perch, Perca fluviatlis), as well as a small-scale study of zooplankton distribution in the small, shallow and eutrophic Lake Hanebjerg in Denmark. In the small-scale study, sampling was conducted in open water as well as in the edge zone immediately outside two different types of vegetation. 2.
Abstract: Simple models, based on Lotka-Volterra types of interactions between predator and prey,... more Abstract: Simple models, based on Lotka-Volterra types of interactions between predator and prey, predict that enrichment will have a destabilizing effect on populations and that equilibrium population densities will change at the top trophic level and every second level below. We experimentally tested these predictions in three aquatic food web configurations subjected to either high or low nutrient additions.
It is well known that the effects of direct (lethal) predator-prey interactions propagate through... more It is well known that the effects of direct (lethal) predator-prey interactions propagate through food webs (the trophic cascade). However, in the present study we show for the first time that, parallel to the trophic cascade, there exists a" behavioral cascade" in the sense that behavioral responses, induced by the nonlethal presence of a top predator, are transmitted down the food chain over more than one trophic link.
Abstract In Lake Washington, juvenile sockeye salmon (Oncorhynchus nerka) strongly prefer Daphnia... more Abstract In Lake Washington, juvenile sockeye salmon (Oncorhynchus nerka) strongly prefer Daphnia over other prey, switching uniformly to Daphnia when the threshold abundance of 0.4 Daphnia L− 1 is achieved.
In order to disentangle if and when resource supply and adult and young-of-the-year (0+) fish pre... more In order to disentangle if and when resource supply and adult and young-of-the-year (0+) fish predation affect zooplankton dynamics during spring, we monitored zooplankton during three consecutive years in a lake in southern Sweden. We also experimentally assessed 0+ fish predation rates and estimated changes in predation rates of adult fish on zooplankton. Decline in abundances of large-sized zooplankters in early spring was not caused by 0+ fish predation.
Abstract The interactions between consumers and prey, and their impact on biomass distribution am... more Abstract The interactions between consumers and prey, and their impact on biomass distribution among trophic levels, are central issues in both empirical and theoretical ecology. In a long–term experiment, where all organisms, including the top predator, were allowed to respond to environmental conditions by reproduction, we tested predictions from 'prey–dependent'and 'ratio–dependent'models.
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Papers by Pia Romare