Wilhelmine rule in German South West Africa was not the sole inspiration for [Fascist] policies in Eastern Europe, but it contributed ideas, methods, and a lexicon that Nazi leaders borrowed and expanded. Language, literature, media, institutional memory, and individual experience all transmitted these concepts, methods and terms to the [Fascists].

[…]

Colonial Namibia’s death camp at Shark Island was different from Spanish and British concentration camps in that it was operated for the purpose of destroying human life. Thus, it served as a rough model for later [Fascist] Vernichtungslager, or annihilation camps, like Treblinka and Auschwitz, whose primary purpose was murder.

The second variant, German South West African work camps, were also innovative: geared not merely toward incarcerating guerilla rebels and potentially sympathetic civilians, as in Cuba and South Africa, their purpose was to extract economic value from prisoners under conditions that camp administrators anticipated would lead to mass fatalities. Thus, the Second Reich’s colonial Namibian work camps provided a rough template for Third Reich concentration camps like Buchenwald and Dachau.

(Emphasis added.)

For a comprehensive look at this important subject, see The Kaiser’s Holocaust: Germany’s Forgotten Genocide and the Colonial Roots of Nazism.