Predicting impacts of an invading copepod by ecological assessment in the animal's native range

Karl Havens, John Beaver
2014 INLAND WATERS  
We assembled data from 11 years of observational research on zooplankton in subtropical Florida, USA, lakes to determine potential impacts of the copepod Arctodiaptomus dorsalis on biodiversity and biomass of co-occurring crustacean zooplankton. This synthesis provided insight into how the species might impact plankton in limnologically similar lakes that it invades outside of its native range. A. dorsalis recently was found in the Philippines, and it was suggested that it could invade lakes in
more » ... Asia and reduce biodiversity. In 7 shallow eutrophic lakes in Florida, we found no relationship between relative biomass of A. dorsalis and number of species of crustacean zooplankton, and we were equally likely to find a similar-sized copepod Diaptomus floridanus in lakes with or without A. dorsalis. In Lake Okeechobee, where a 7-year dataset existed for crustacean zooplankton, we found no evidence that A. dorsalis impacts the biomass of cladocerans or other dominant copepods. Gut analysis and grazing experiments documented that A. dorsalis is capable of eating bacteria and nearly all phytoplankton taxa, including cyanobacteria. This ability to exploit a broad range of resources and to execute rapid escape maneuvers to avoid fish predation may explain why A. dorsalis often is dominant in shallow eutrophic lakes with high densities of omnivorous fish. We conclude that A. dorsalis will not negatively affect the biodiversity of plankton in similar lakes of Asia; instead, it may fill a vacant niche in lakes with high fish predation where other copepods cannot survive. Further research is needed to determine how A. dorsalis will influence the plankton in less enriched lakes where food resources may be limiting.
doi:10.5268/iw-4.1.632 fatcat:pqyyhvu5ubc3bhfiep2oy7gv3u