If you can establish NWSG and wildflowers they will compete with other plants that are undesirable to wildlife quite well. If you�re planting right now an annual like annual rye grass or frost hardy winter wheat which makes it what to plant in the north you�ll be able to seed NWSG the next late spring or early summer by very lightly roughing up the surface, seeding, and restrawing. On an area such as a newly built dam that is more then likely subsoil and has very little seeds that will compete you�ll have very little competition. With NWSG being naturally selected for thousands of years for your area and its climate and with their 6-8� root systems they�re perfect for erosion control for a dam. I seeded mine this way last year and I�m doing the same thing with the area that we moved the dirt to that we dug making our pond bigger last week.