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Long‐term impact of an invertebrate predator, Heterocope septentrionalis , on an arctic pond zooplankton community
Author(s) -
O'Brien W. John
Publication year - 2001
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.2001.00650.x
Subject(s) - zooplankton , daphnia pulex , bosmina , predation , biology , ecology , population , invertebrate , predator , pulex , branchiopoda , arctic , fishery , daphnia , cladocera , demography , sociology
1. A long‐term field experiment to determine what forces structure and maintain the large‐bodied zooplankton assemblages in ponds which lack visual predators was undertaken at the Toolik Lake Research Station in arctic Alaska. Predatory copepods, Heterocope septentrionalis, were introduced to a pond that lacked both fish and invertebrate predators, but contained small‐ to medium‐sized zooplankton, Bosmina longirostris , Daphnia pulex , and Diaptomus pribilofensis. A second pond, which also lacked any predators but had a population of B. longirostris , but no other abundant species, served as a reference population for B. longirostris.
2. The introduction of H. septentrionalis caused the extinction of D. pulex within 1 year and drove B. longirostris to extremely low densities within 4 years. The population of B. longirostris in the reference pond fluctuated throughout the study period, but remained above five individuals per litre. This experiment demonstrates that H. septentrionalis , under natural conditions, made a numerical response to abundant prey and had the capacity to eliminate or reduce vulnerable prey populations of small‐ to medium‐sized zooplankton.