Seed Bank

Death Valley 4/8/16

Flowers are desert chicory (Rafinesquia neomexicana), pebble pincushion (Chaenactis carphoclinia), golden evening primrose (Camissonia brevipes), desert dandelion (Malacothrix glabrata), showy gilia (Gilia cana triceps) to mention a few. 
Soil seed bank, to be precise. These are flowers in Death Valley, many of which are annuals, germinating from seeds in a rare year when rains are sufficient. Look up "Superbloom." The seeds have been in the soil for years, waiting for the right rains to come. 
The Soil Seed Bank is the repository of seeds in the leaf litter, soil surface, or soil layer. They are like a bank in that they are available for germination in a landscape that has failed to produce seeds in one growing season or more. This failure can happen in times of drought, fire, landslide, floods, hail, human disturbance. The seeds in the seed bank may germinate when favorable conditions return, restoring the historic array of species. That is, as long as the seeds remain viable over the course of the unfavorable conditions.
Seed banks are found wherever plants, animals, wind or other vectors deposit seeds: in the black prairie soils, the bottom of lakes, the muck in swamps, bogs, and marshes, dunes, badland soils, and even permafrost. Some species of seed may be viable for decades, even centuries. In 2012, Russian scientists regenerated Silene stenophylla (narrow-leaved campion, a plant found in Siberia and northern Japan) from a 32,000-year-old late Pleistocene seed that had been buried in the permafrost. Although this specimen wasn't regenerated from a seed, it indicates a potential for ancient germplasm in ice-age seed repositories. 
Some of the seeds in our modern soils may have a very long viability in the seed bank. In 1879, botanist William Beal put seeds from 20 species in glass bottles and buried them 20 inches deep. Every 5, 10, or 20 years scientists have dug up a bottle of his seeds to see which ones germinate. In 1980 they were able to germinate moth mullein (Verbascum blattaria), common mullein (Verbascum thapsus) and common mallow (Malva neglecta), over 100 years after their burial. 
So, the natural cycles of disturbance may play within these time limits, but we are not convinced that anthropogenic disturbances play by the rules. Like the story of the Romanov family, we have the alarming capacity to eliminate a whole lineage in one dark night.