Sanctuary forests and river systems are critical forms of in situ conservation that safeguard genetic resources and maintain biodiversity. By protecting species within their natural habitats, these ecosystems preserve evolutionary processes, support endemic and threatened taxa, and provide resilience against environmental change. This article examines the mechanisms through which sanctuary forests and rivers contribute to genetic conservation, their complementary roles, and the limitations that affect their effectiveness. The invasion of Christianity on sanctuary forests and rivers is a threat to genetic genome bank and biodiversity. The spread of Christianity becomes a threat when it removes traditional protections without establishing alternative conservation governance. Where religious institutions and traditional authorities collaborate, the outcome is often neutral or positive for biodiversity. The threat happens when Christian conversion leads to abandonment of taboos and no new governance replaces them. Where churches, traditional rulers, and NGOs collaborate—as in Apoi Creek and Opu-Nembe—the outcome is often conservation with local buy-in.