An expert-based global assessment of threats and conservation measures for subterranean ecosystems

Subterranean ecosystems host unique biodiversity and deliver important services to humans. Yet, available data for subterranean ecosystems are limited in space and/or taxonomic scope and global monitoring programs are absent, preventing practitioners to develop effective conservation and management strategies. Expert opinion may help overcome some of these knowledge gaps. We designed a global survey to quantify the importance of anthropogenic impacts and conservation measures for subterranean ecosystems. We obtained 279 responses from 155 experts in different subterranean habitats, taxa, and regions. Experts perceived surface habitat change, direct habitat destruction (e.g., pollution, damming, mining), and climate change as the most relevant threats impacting subterranean ecosystems. Legislation, land protection, and education were scored as the most effective conservation measures, whereas species-level conservation was deemed less relevant. Whenever lacking hard data, expert opinion may be an effective, largely available, yet often overlooked source of information to implement timely conservation interventions for subterranean ecosystems. ### Competing Interest Statement The authors have declared no competing interest.