Was doing some digging around on modern uses of the word ranger . . . . and I'm coming up with two broad uses.
The word originally seems to refer to someone who patrols, or ranges, over an area in a protective capacity . . . but not protecting citizens from the dangers of nature, but rather protecting a hunting area from the citizens for the elite. This concept evolves into today's park rangers, who patrol nature reserves to protect them from folks who would otherwise despoil them. Park rangers also, of course, have the mandate to protect visitors, tourists, from the dangers of the wild, or from their own lack of survival skills . . .
There is also the military ranger . . . military units that patrol, or range, over the landscape as scouts and guides. This meaning seems to have evolved into rangers-as-commandos . . . highly skilled, mobile troops who insert themselves into a landscape for all sorts of missions, including scouting, guiding, ambushing, assassination . . .
Tolkien's ranger, the basis for the D&D class, seems to evolve the word a bit further into solitary soldiers who roam the wilderness dealing with threats to citizens . . . monsters, orcs, servants of the Dark One . . . There's also the elven connection . . . Aragorn and the Rangers of the North were close allies to the House of Elrond and received training there . . .
Rangers aren't survivalists . . . but certainly employ wilderness survival skills in the course of their jobs. They aren't protectors of nature, not really, although modern park rangers might just view that as legitimate aspects of their jobs, and certainly have a reverence and love of nature. They have no connection to druids (IRL) or other "primal" or nature-serving specialists.
Fictional characters who have an affinity for nature, for animals . . . might fit into a very broad D&D ranger concept, but not into the classic D&D ranger concept. Most of the examples listed in this thread past Aragorn the Strider . . . . nah, not seeing it.
One thing I find humorous about the evolution of D&D's ranger . . . words pretty synonymous with ranger, including warden and forester, have been used to create ranger-like classes in the game to co-exist alongside the ranger for some reason . . .