as others said,
call the cops and game commission
cops investigate the tresspassing, PGC follow up on the poaching,
they can and will work together,
PA has different levels of tresspasing,
from simple tresspassing for non posted properties
and criminal tresspassing on posted properties.
if posted , that is your notification,, no need to confront them to remind them,
if you know who is doing it, let the cops and pgc know,
as they will keep a look out while driving by and on patrol,