San Diego Ambrosia, a perennial herb in the sunflower family The San Diego County Board of Supervisors postponed a vote that would approve building a warehouse distribution center at Gillespie Field - which Amazon is expected to lease - in order to review the environmental studies. But environmental advocates say the city of El Cajon has already relocated 23,000 federally endangered San Diego Ambrosia plants from the county-owned land. "There's a problem here that we need to get to the bottom of," Frank Landis, Conservation Chair of the California Native Plant Society, told supervisors at the March 3rd meeting. "[The Amazon warehouse land] is a non-aviation private land lease on county-owned property associated with Gillespie Field Airport."