More than 1,000 seed banks across the globe are preserving frail ecosystems as the Earth warms. The California Botanic Garden seed bank holds the genes of more than 6,000 species of seeds. It can take years of collection efforts to extract some of them. Rare plants are rare for a reason, says botanist Naomi Fraga. They might have reproductive issues, so we might only get like 100 seeds one year. Sometimes, the botanists get lucky and find well-preserved samples in the wild. In 2012, scientists brought back Silene stenophylla because ancient Siberian squirrels 32,000 years agostored the berries of the flowering plant. Because examples like this exist in the wild, scientists are optimistic that seed banks can secure biodiversity and help spur food security.