The purpose of this study was to assess how traditional ecological knowledge systems can be leveraged to achieve biodiversity conservation and build resilience to climate change. A sequential mixed-methods approach was used to study 379 local people residing around the Nyungwe National Park, Rwanda. Rusizi district was purposively sampled and as well as three sectors in it, within which random sampling was used to sample the villages, in which households were sampled conveniently and the locals purposively. Structured interviews and focus group discussions were used to collect data. Quantitative data collected were analyzed in SPSS 25 and the qualitative data was thematically analyzed. The results indicate that all biodiversity conservation principles were practiced by 71% (n = 270) of the local people. The widest spread species in Nyungwe National Park are trees (n = 219, 57.8%). However, bush burning is practiced outside the park (n = 328, 86.5%). Controlled tree cutting (adjusted odds ratio, AOR = 1.167, CI = 1.007–2.032), and awareness of biodiversity and practice measures that usually avoid harm to biodiversity (AOR = 1.610, CI = 1.029–2.519), are protective of biodiversity conservation. Biodiversity conservation is not universal among locals residing around Nyungwe National Park; only 7 in 10 of them are conservation-oriented. Knowledge about forest conservation and controlled bush-burning practices are most protective of conservation.