Linking demographic and habitat suitability modelling identifies the environmental determinants of successfully controlling invasive common carp ( Cyprinus carpio ) in south-eastern Australia

Common carp ( Cyprinus carpio ) are a serious invasive species of riverine habitats in Australia and several control measures have been proposed. The strategy and potential success of any control measure will be influenced by carp population dynamics. Carp survival and distribution are driven by abiotic environmental factors (e.g., water flow rates and habitat availability), which vary greatly in space and time in Australian river systems. To inform realistic control strategies, we developed a mechanistic (process-based) carp metapopulation model with parameters explicitly linked to spatio-temporal estimates of habitat suitability. To demonstrate the use of this model, we evaluated how recovery times following a one-time management action (that results in population reduction) varied across five river catchments in the Murray-Darling Basin (MDB), eastern Australia, using reconstructed environmental conditions from the early 1990s to 2016. We found that recovery time at the catchment scale can be highly dependent on the flood-drought cycle, with recovery varying from to 2 to 10 years between wet and dry periods. In more stable catchments, however, ~ 6 years (range 4–8 years) is more likely. Our results are consistent with the paradigm that carp are a highly successful invasive species, with strong recovery potential, especially during periods of access to quality nursery habitat (i.e., during floodplain and wetland inundation).