  Experiments measuring cosmic rays above an energy of 10^14 eV deduce the
energy and mass of the primary cosmic ray particles from air-shower
simulations. We investigate the importance of hadronic interactions at low and
high energies on the distributions of muons and electrons in showers on ground.
In air shower simulation programs, hadronic interactions below an energy
threshold in the range from 80 GeV to 500 GeV are simulated by low energy
interaction models, like Fluka or Gheisha, and above that energy by high energy
interaction models, e.g. Sibyll or QGJSJet. We find that the impact on shower
development obtained by switching the transition energy from 80 GeV to 500 GeV
is comparable to the difference obtained by switching between Fluka and
Gheisha.
