The science and application of ecological monitoring

We provide a broad overview of the underlying philosophy of ecological monitoring. We argue that the major characteristics of effective monitoring programs typically include: (1) Good questions. (2) A conceptual model of an ecosystem or population. (3) Strong partnerships between scientists, policy-makers and managers. (4) Frequent use of data collected.We classify monitoring programs into three categories – (1) Passive monitoring, which is devoid of specified questions or underlying study design and has limited rationale other than curiosity. (2) Mandated monitoring where environmental data are gathered as a stipulated requirement of government legislation or a political directive. The focus is usually to identify trends. (3) Question-driven monitoring, which is guided by a conceptual model and by a rigorous design that will typically result in a priori predictions that can be tested.There are advantages and disadvantages of mandated monitoring programs, which are typically large-scaled, and generally smaller-scaled, question-driven monitoring programs. For example, while question-driven monitoring programs can provide insights into the ecological processes giving rise to emergent environmental patterns, spatial generalization from them is difficult because results may not extrapolate well to other regions, states or to a national level. Conversely, while mandated monitoring can be useful for producing coarse level summaries of temporal changes in a target population or resource condition they may not identify the mechanism influencing a change in an ecosystem or an entity. A key remaining challenge is to develop much improved mandated monitoring programs through more widespread adoption of the features of successful question-driven monitoring programs in efforts to enhance biodiversity conservation and environmental management.