Tourist leave gates open, allowing animals to escape.
Tourists park on grass verges, leading to soil erosion. e.g. Luss.
Traffic congestion on narrow roads leads to air/noise pollution
Tourists causing footpath erosion and wandering off the paths, causing erosion elsewhere.
Stone walls can be damaged by tourists climbing over them.
Wild camping damages grass, open fires, litter.
Dropped litter can be eaten by wildlife = harm or kill them.
Dogs off the lead can scare sheep, they can have miscarriages or die and lose the farmer money.
Speed boats on Loch can erode beaches and leaking engine oil harms aquatic life.
Tourists buying holiday homes pushes prices up for locals and can lead to rural depopulation, leading to reduced demand for services, leading to closures.