Try a mix of elmers glue and water. If your habitat material is real heavy you may need to glue down the bigger pieces individually. But for the leaves and twigs and grass and such, just spray the base with a 2 parts water to 1 part elmers glue in a misting bottle.Scatter your material on the dampened base and then spray it again with an even coat to cover everything, that should lock it all down very well. Give it a shot.Good Luck.