How monitoring matters for nature conservation: 15 reasons framed in a theory of change

Monitoring is essential for nature conservation, but many programmes are criticized for lacking purpose. We argue that monitoring delivers impact only when grounded in a clear theory of how activities lead to change. We clarify and categorize 15 distinct reasons to monitor within a theory-of-change framework, outlining how these can guide decisions about where to invest effort. These reasons fall into five groups: basic and applied research aimed at causal evaluation; monitoring integrated with on-ground actions; monitoring to inform policy; monitoring that strengthens enabling conditions for conservation; and curiosity-driven monitoring. Efforts to quantify the benefits of monitoring often focus on narrow, intervention-specific purposes, typically within adaptive management or evidence-based conservation approaches. However, much ecological monitoring serves functions beyond these frameworks. A broader perspective reveals additional, often overlooked, reasons to monitor, especially those that build the enabling conditions required for effective policy and practice. The benefits of these reasons for monitoring have rarely been articulated or quantified. Before designing a monitoring programme, conservation organizations should articulate a theory of change that makes their reasons for monitoring explicit. We provide a checklist of 15 reasons to support transparent logic, intentional design and clear links between monitoring information and improved policy or management outcomes.