Information gaps in indigenous and local knowledge for science-policy assessments

The need to understand nature's contributions to people and across a broad spectrum of cultures and ecosystems is increasingly advocated in science assessments and policy decision-making for sustainability. However, for services such as food and medicine, gaps in existing studies on indigenous and local knowledge may preclude inclusive assessments. Here, using a large database of indigenous and local knowledge about plant services for New Guinea, we show that there are biological and cultural documentation gaps that will exclude many plant services and indigenous groups from assessments that are based solely on published research. Further, we unveil that, like the common property of 'rarity' in species assemblages, most plant services exhibit high rarity. Gaps and rarity are probably pervasive in other regions and will affect how plant services are conceptualized, assessed and sustainably managed.