They're loose impediments. Brush them away. Just don't make your ball move.
Your "lie" might improve, but that's fine. You can move a stick if it's unattached, or a rock, or a candy bar wrapper (though now we're no longer talking about "loose impediments" - see the postscript), even if the stick or rock or candy wrapper are immediately behind or in front of your ball.
It's not "improving your lie" in the illegal (against the Rules of Golf) sense.
“Loose impediments’’ are natural objects, including:
- stones, leaves, twigs, branches and the like,
- dung, and
- worms, insects and the like, and the casts and heaps made by them,
provided they are not:
- fixed or growing,
- solidly embedded, or
- adhering to the ball.
Sand and loose soil are loose impediments on the putting green, but not elsewhere.
Snow and natural ice, other than frost, are either casual water or loose impediments, at the option of the player.
Dew and frost are not loose impediments.