Very nice! 
Must admit to being a little concerned by what looks like rust on the bonnet & passenger's door (Land Rover bodywork being all aluminium) but I could explain that away as tannins from rotted foliage bonded to the oxidised aluminium.
You answered your own curiosity.
Or it’s local dirt and dust that has accumulated. Any red clay roads in the area?
Could be many reasons. I searched many photos of such subject matter and there were a few with this type of coloration. So, again, this is not rust.
