Species Introduction in a Tropical Lake: A newly introduced piscivore can produce population changes in a wide range of trophic levels.

摘要: Probably in early 1967, a piscivore from South America, Cichla ocellaris, was introduced to Gatun Lake the Panama Canal Zone. As this predator population spread through lake, initial effect dramatic reductions almost all secondary consumers. These species produced, turn, second- and third-order changes at other trophic levels of ecosystem. The resulting lake community can be seen best by examining general food web. decrease numbers important planktivore Melaniris has resulted within zooplankton community, as illustrated cladoceran Ceriodaphnia. tertiary-consumer populations, such tarpon, black terns, kingfishers, herons, formerly dependent on small fishes for food, appear less frequently areas lake. There also been, possibly, resurgence local mosquito populations (which are malaria vectors), caused reduction insect-eating fishes. Even primary producers may affected introduction. Although present ecosystem is undergoing rapid changes, we anticipate an eventual return some form equilibrium. However, it will time before evaluate permanence or transience many produced introduction single, top-level system.