Hypsilophodonts, like Gasparinisaura were one of many animals that where found fossilized in the footprint of a large Sauropod, when the animals had to cross a volcanic ashfield, the large Sauropod's footprints would have turned the ground beneath them into quicksand, meaning any animal that fell in the footprint met a drowning death. For protection, it lived in Argentinasaurus herds. and browsed on the ferns and other planets that the giant argentinosaurus ingnored. however liveing with such large animals does carry risks they could easily be squashed or trampled by the huge sauropods
Gaspariniasaura was a small herbivore with very long legs which meant it could run reasonably fast. It's small size meant that it could get into places in which were to small for bigger dinosaurs meaning that it could escape for big predators. It's size also meant that it needed less food than a giant sauropod like argentinosaurus meaning that it would not be hit so hard if a sudden shortage of food happened.