• invasive species;
  • feeding tactics;
  • prey selection;
  • freshwater fishes

Abstract –  Feeding tactics, body condition and size structure of two populations of pumpkinseed Lepomis gibbosus from Cabañeros National Park (Guadiana River basin, central Spain) were compared to provide insight into the ecological requirements favouring levels of success/failure in relation to human intervention. Habitat, benthic macroinvertebrates and pumpkinseed were quantified in Bullaque (regulated flow, affected by agricultural activities) and Estena (natural conditions) rivers, from May to September of 2005 and 2006. Significant differences were found in the limnological characteristics between the two rivers. Spatial and temporal variations in diet composition were likely related to opportunistic feeding and high foraging plasticity. Diet diversity was higher in Bullaque River. Electivity of benthic prey showed variation between sized individuals and populations. The body condition of pumpkinseed was better in Bullaque River. Current results show that this invasive species is favoured by human intervention in Bullaque River.