Columbey National Park was reserved due to its significant vegetation features, including twelve vegetation communities. Three of these communities are listed as endangered ecological communities. These are the Lower Hunter Spotted Gum – Ironbark Forest, Floodplain Redgum-Box Forest, and Hunter Lowlands Redgum Forest.
Recent fauna surveys recorded the vulnerable small marsupial brush-tailed phascogale in the park. The park provides suitable habitat for other threatened animal species which have been recorded nearby and may be present in the park.