Lander says, "I can cause plants to grow more, nothing extreme, but enough to delay and annoy them. I could also try to have the animals do more damage."
That is a good start. We can also fray the lashings that keep the thatch in place so that a decent wind or movement will cause the thatching to fall off. We can do the same to the hut structures and beds. If there are any cisterns or water barrels, loosen the joints or put holes in them so most of the water leaks out. If it looks like they are using the plants on the island as a food source, we can strip the edible food bare or ruin it.
Maybe we can do something to the path up from the cove. I don't mean set any traps, that would be too obvious, but make the path harder to traverse.
Falcon will take a look around at the campsite to see just what can be done to make life aggravating for the pirates. Also, he will take a look at the path(s) down to the cove and see what can be done there