State‐dependent invasion windows for prey in size‐structured predator–prey systems: whole lake experiments

摘要: 1. In size-structured communities where individuals grow in size over their life cycle, interactions between species will shift competitive and predatory depending on relationships. The outcome of subsequently depend the strength interactions, respectively. 2. a whole lake experiment including four experimental lakes, it was tested under which conditions competing prey, roach Rutilus rutilus, could successfully recruit into systems previously occupied by predator, perch Perca fluviatilis. Two replicated introduction experiments were carried out 3 years apart. 3. Roach able to three lakes two also inhabited top predator pike Esox lucius. Resource levels unrelated whether as recruiting all feeding close maximum rate. 4. High population fecundity low predation pressure combined necessary ingredients for successful recruitment presence only one these did not result recruitment. 5. It is hypothesized that, although with present addition that pike, long-term coexistence depends another (e.g. pike) selectively preying perch. This hypothesis supported data co-occurrence different lakes. 6. Overall, results are accordance expectation life-history omnivory theory suggesting intermediate consumer fragile.