The US forests got used to not having them, so now some trees like maples need a thick layer of leaves on the ground to trap moisture around their roots so they don’t dry out. There are also native plants that need this layer to help protect them from temperature swings.
A couple of sources: https://nysufc.org/earthworms-implicated-sugar-maple-decline/2017/11/28/ https://wormwatch.d.umn.edu/forest-ecology-and-worms/forest-ecology/about-forest
And more penguin species live outside the Antarctic region than in it