Forb seeds can be extremely long lived....which is great news for small ruminants (deer, goat and sheep) because their diet is rich in such plants when available. Why is that an ecological advantage? When catastrophic events weaken or destroy above ground vegetation or the soil upper surface, there will always be a forb seed available to restore soil function and start plant succession anew. Note, that many annual grass seeds are fairly short lived....thus, we have plants which are capable of restoring soil function and starting plant success given repeated annual catastrophic events. Attempting to control the inevitable 'weed'....is a mere exercise in futility....given the longevity of seed and myriad of seed dispersion avenues! The best we can hope to achieve is to keep forb density in line with management goals.
Weed Seeds and Their Longevity
https://www.no-tillfarmer.com/articles/6290-weed-seeds-and-their-longevity-dnt
Weed Seeds and Their Longevity
https://www.no-tillfarmer.com/articles/6290-weed-seeds-and-their-longevity-dnt