Indigenous: the word describes a species of plant which originated and evolved in the place where it is found. The dictionary definition should be enough to show what is meant by indigenous vines, an inheritance which is indissolubly linked to an area's past.
This inheritance risked being wiped out by the arrival of phylloxera, which led to the planting of vines more orientated towards the market than to tradition. Even now the whole world has heard of the international varieties of vine (Chardonnay, Cabernet, Pinot, Sauvignon) which were taken to the new vinegrowing countries with little tradition of winemaking (California, Australia, New Zealand) and which force many producers to follow them along this road, forgetting the many varieties linked to thousands of years of history.
Luckily nowadays in countries with an ancient viticultural tradition, like Italy - where each area has its indigenous varieties developed over centuries - people are rediscovering the unique features of these grape varieties, the indelible result of an area and its history.