Seeds of change: trait shifts over time in wild plant populations revealed using

Seed banking supports conservation, but freshly collected and stored seed may differ in important characteristics. Our resurrection study assessed differences in seedling traits from stored and fresh populations of six native plant species in the Great Basin, where invasive annual grasses increase fire frequency to the detriment of native plants. We evaluated stored seed collected through the Seeds of Success programme and contemporary re-collections from the same population 3-11 years later, including sites that burned between collection dates and paired, unburned sites. We sowed seeds in a common garden and measured differences in seed mass, emergence (timing and total), survival, and multiple size traits. We observed temporal changes in trait means for at least one trait in every species irrespective of burn history. The direction of change varied among species, and very few traits changed in variance. Seed mass and emergence traits changed most frequently (12 of 17 measures changed over time), with fewer changes in mortality and size traits (6 of 24). Changes may reflect sampling, ageing, or maternal effects, or changes in gene frequency from drift or natural selection. Evidence consistent with adaptive evolutionary response to disturbance was observed in