Short-term fish predation destroys resilience of zooplankton communities and prevents recovery of phytoplankton control by zooplankton grazing

摘要: Planktivorous fish predation directly affects zooplankton biomass, community and size structure, may indirectly induce a trophic cascade to phytoplankton. However, it is not clear how quickly the structure cascading effects on phytoplankton recover unaffected state (i.e. resilience) once short-term by stops. The resilience has implications for ecological quality restoration measures in aquatic ecosystems. To assess against predation, we conducted mesocosm experiment consisting of 10 enclosures, 6 with 4 without fish. Plankton communities from natural lake were used establish mesocosms. High biomasses (about 20 g wet mass m-3) juvenile planktivorous (perch, Perca fluviatilis) allowed feed enclosures four days. Thereafter, removed observed recovery its effect interactions comparison no weeks. Short-term impaired modifying composition, as large zooplankton, such calanoids, decreased just after did re-appear afterwards, whereas small cladocerans rotifers proliferated. Total biomass increased within two weeks removal, at end even exceeded measured before addition. Despite high dominance released grazer control enclosures. Accordingly, indicating low resilience. In contrast, disturbance, zooplankton:phytoplankton ratio accompanied yield (Chlorophyll-a:Total phosphorus ratio) reflected over experimental period. Comprehensive views short long-term are essential management strategies ecosystems better predict responses global warming, higher densities