Alpacas live very lightly on the land.  Their soft padded feet and their light weight mean that they don't tear up the landscape.

The fact that the dung piles are cleaned up daily means that there is a minimum of run-off from alpaca waste.

Alpacas have three-part stomachs that digest hay and grass very efficiently.  They don't eat a great deal, nor do they require or even do well on rich, high-protein diets. This means that the need for herbicide and pesticide application on their pastures is minimal if you use them at all.

Alpacas don't challenge fences.  The real need for fencing is around the perimeter of the alpaca pasture-barn area to protect them from predators.