The destruction of the Amazon rain forest by commercial forces—and of the lifestyle of its indigenous people—is the underlying theme of Colombian director Ciro Guerra’s remarkable historical drama “Embrace of the Serpent,” but it’s dealt with obliquely, through the figure of Karamakate, a shaman and one of the last survivors of his tribe, who interacts with European explorers at two points in his life, revealing through the juxtaposition of those experiences the impact of western colonialism on his world. Shot by cinematographer David Gallego in luminous widescreen black-and-white (except for a brief burst of color in a transcendent finale) and smoothly edited by Etienne Boussac and Cristina Gallego, the film captures the wonder of the setting, but insistently provokes meditation on its degradation in the face of commercialism and foreign influence.

The script by Guerra and Jacques Toulemonde is an imaginative construct loosely derived from the travel diaries of two real-life explorers, Theodor Koch-Grunberg and Richard Evans Schultes. Karamakate first appears in the person of Nilbio Torres, who in 1909 is living a solitary existence in harmony with the forest, following the traditional rules of respecting one’s surroundings. He’s approached by Manduca (Yauenku Miguee), a semi-westernized native from a different tribe, who brings with him Theo (Jan Bijvoet), a German explorer who has fallen ill. They’re seeking a legendary—perhaps non-existent—flower called the yakruna, which might be the only thing that can save him. Rightfully indignant over the impact of rubber companies on the land, Karamakate at first refuses to help in their search, but when Theo remarks that he’s met others of Karamakate’s tribe, the Cohiuano, they reach an agreement: if the shaman will take him to the flower, Theo will show him where the remnant of his people can be found. A mystical dream involving a jaguar and the serpent of the title is an important part of the equation.

Episodes from that early journey are intercut with those from one that occurs nearly forty years later, when Karamakate (now played by Tifillama-Antonio Bolivar Salvador) is approached by another European, Evan (Brionne Davis), who claims to be a biologist searching for the yakruna for purely scientific reasons. The old shaman, who claims to have forgotten the earlier journey, agrees to accompany the man on his search, which—of course—is not a simply scientific one. Throughout both journeys the majesty of the river is emphasized, as are the habits of mind that Karamakate is at pains to impart to the outsiders as the means of living in proper conformity with the environment and preserving it. He’s particularly averse to westerners’ obsession with things—a materialism that he derides as crazy, though he’s open to appreciation of foreign beauty, like the orchestral introduction of Haydn’s “Creation” that Evan plays for him on the crank-style phonograph he carries about with him (a nod to Herzog, no doubt).

But along the way there are powerful proofs of the dire impact of colonialism and the “progress” that it inevitably brings on the region and its people. That’s certainly evident at the end of the first journey, when Karamakate comes face to face with the reality of what has happened to his people and responds with fury. (An earlier moment, when the group encounters one of the natives forced into slave labor at a rubber plantation, is no less dramatic.)

But it’s an encounter with a dictatorial friar (Luigi Schiamanna) at a Franciscan mission that makes the deepest impression; the excoriation of religious imperialism is as shocking as anything one will find in Bunuel’s “Viridiana.” During the 1909 stopover, the priest’s treatment of the children under his control—youngsters orphaned when their parents were forced onto the plantations—is brutal, totally insensitive to the local culture. But what the travelers find in the forties is even more appalling: the cleric’s acolytes have become a grotesque cult led by a self-proclaimed messiah (Nicolas Cancino) and practicing a perverted version of Christianity that, in its insane literalism, ultimately integrates the worst of local custom into its ritual.

Yet “Embrace of the Serpent” is not merely an assault on cultural and socio-economic contamination. In an astonishing culmination it suggests that might still not be too late for humanity to reach an enhanced understanding that will bring the species into harmony with the cosmos. A visually captivating finale rivaling the head trip of “2001: A Space Odyssey” makes the point.

Presumably one could dispute, from a theoretical perspective, the implicit criticisms of western capitalism and the colonialism it spawned that Guerra’s film dramatizes. But from a purely cinematic standpoint this cinematic journey into an Amazonian heart of darkness is a haunting and unforgettable experience.