Related Experiment Video
Updated: Jul 18, 2026
06:25
A Real-Time Interactive System for Studying Confrontational Pursuit Behavior in Rodents
Published on: May 16, 2025
State-dependent invasion windows for prey in size-structured predator-prey systems: whole lake experiments
Lennart Persson1, André M De Roos, Pär Byström
1Department of Ecology and Environmental Science, Umeå University, SE-90187 Umeå, Sweden. Lennart.Persson@emg.umu.se
The Journal of Animal Ecology
|December 23, 2006
Summary
Successful roach recruitment into perch-inhabited lakes requires high roach fecundity and low perch predation. Long-term coexistence of roach and perch is fragile without a top predator like pike.
Area of Science:
- Ecology
- Aquatic ecosystems
- Population dynamics
Background:
- Species interactions shift between competition and predation in size-structured communities.
- Individual growth influences interspecific dynamics, affecting community structure.
- Understanding recruitment dynamics is crucial for managing aquatic ecosystems.
Purpose of the Study:
- To determine conditions for successful roach (Rutilus rutilus) recruitment in lakes with perch (Perca fluviatilis).
- To investigate the role of size-structured interactions in predator-prey dynamics.
- To test hypotheses regarding the influence of fecundity and predation pressure on prey recruitment.
Main Methods:
- Whole-lake introduction experiments with roach into four experimental lakes.
- Two replicated experiments conducted three years apart.
- Monitoring roach recruitment, population fecundity, predation pressure, and resource levels.
Main Results:
- Roach successfully recruited into three of four lakes, with two also containing pike (Esox lucius).
- Successful recruitment depended on high roach population fecundity and low perch predation pressure.
- Resource levels did not significantly impact roach recruitment success.
Conclusions:
- Coexistence between roach and perch is fragile and dependent on the presence of a top predator (e.g., pike) that preys on perch.
- Size-structured life-history omnivory theory predicts fragile coexistence between top predators and intermediate consumers.
- Ecological dynamics in size-structured communities are complex, requiring multiple factors for stable species interactions.
Related Concept Videos
02:39Predator-Prey Interactions
Predators consume prey for energy. Predators that acquire prey and prey that avoid predation both increase their chances of survival and reproduction (i.e., fitness). Routine predator-prey interactions elicit mutual adaptations that improve predator offenses, such as claws, teeth, and speed, as well as prey defenses, including crypsis, aposematism, and mimicry. Thus, predator-prey interactions resemble an evolutionary arms race.Although predation is commonly associated with carnivory, for...
00:30What are Populations and Communities?
Populations are groups of individuals of the same species that inhabit a shared environment. Communities include multiple co-existing, interacting populations of different species. Metapopulations span multiple populations of the same species that occupy different areas. Metapopulations interact through immigration and emigration, providing genetic diversity that lends resilience to harsh environments. Population size and density can be estimated using quadrat and mark and recapture...
01:28Microbial Interactions: Predation
Microbial predation refers to the process by which one microorganism kills and consumes another to obtain nutrients and energy. It encompasses both bacterial and protozoan predators. This interaction plays a crucial role in shaping microbial communities and regulating nutrient cycling.Bacterial Predators: Epibiotic vs. EndobioticBacterial predators are classified based on their mode of attack as either epibiotic or endobiotic. Epibiotic predators, such as Vampirococcus, attach to the surface of...
02:04Conservation of Small Populations
Small population sizes put a species at extreme risk of extinction due to a lack of variation, and a consequent decrease in adaptability. This weakens the chances of survival under pressures such as climate change, competition from other species, or new diseases. Large populations are more likely to survive pressures such as these, as such populations are more likely to harbor individuals that have genetic variants that are adaptive under new stresses. Small populations are much less likely to...