According to the Plant Conservation Alliance:
Some examples of native spring ephemerals include bloodroot, wild ginger, spring beauty, harbinger-of-spring, twinleaf, squirrel-corn, trout lily, trilliums, Virginia bluebells, and many, many others. These plants provide critical nectar and pollen for native pollinators, and fruits and seeds for other native insects and wildlife species. Because fig buttercup emerges well in advance of the native species, it has a developmental advantage which allows it to establish and overtake areas rapidly.
I'd blogged about some of those flowers on that list as they bloomed in my backyard. Imagen all of them getting replaced by one species that only blooms for a week or two. Granted it's an abundant sources of food but it's whipped out all other nectar sources in the bloom phase. Imagen having a lush garden of one crop that only produces food the first week of June and nothing else for the rest of the year.