Human isolation in mountain areas has an extra cost for the people living there, because they occasionally have to face harsh environmental conditions. Such adaptation to the environment can be faced in several ways, and in situ landrace conservation is a proposed strategy that concerns food acquisition and maintenance. However, human isolation could also be affected as a result of residing inside a protected area. In this paper, we assess the correlation between the in situ landraces conserved by farmers and the location of the farms inside or outside of a protected area (Montseny Mountains Biosphere Reserve and Natural Park). The variables of isolation, calculated as the time needed to reach the nearest market and the effect of altitude, were also considered. We interviewed 28 farmers, 12 inside and 16 outside of the protected area, and identified a total of 69 landraces. Those farms located inside the boundaries of the Natural Park retained more landraces than those located outside. There was also a positive and significant correlation between the landraces cultivated and the degree of isolation. The effect of altitude did not appear to be a relevant variable. Finally, a total of 38 landraces were located only on farms inside the Natural Park, 13 were found outside and 18 were cropped in both territories.