  Chains of parametrically driven, damped pendula are known to support
soliton-like clusters of in-phase motion which become unstable and seed
spatiotemporal chaos for sufficiently large driving amplitudes. We show that
the pinning of the soliton on a "long" impurity (a longer pendulum) expands
dramatically its stability region whereas "short" defects simply repel solitons
producing effective partition of the chain. We also show that defects may
spontaneously nucleate solitons.
