Brett K. Sandercock, Norwegian Institute for Nature Research: Use of Occupancy Models in Ecological Monitoring in Norway

The Norwegian Institute for Nature Research (NINA) is a private research institute with responsibility for monitoring of plants and animals of management interest in Norway: invasive species, harvested species, and red-listed species of conservation concern. Long-term ecological monitoring of these taxa requires efficient sampling methods that provide information on population trends and habitat requirements, while controlling for the problem of imperfect detection rates under field conditions. Occupancy models are a mark-recapture model based on repeated sampling that has the advantage that sampling can be based on detections of unmarked animals. Detections can be recorded with a variety of different kinds of sampling gear, including eDNA for freshwater species, Malaise traps for insects, den checks for mammals, or sound recordings for birds. I will introduce occupancy models and available software tools. To demonstrate the utility of occupancy models for ecological monitoring, I will discuss a variety of recent case studies where models based on single season sampling, multilevel sampling designs, and multiple detection states have provided insights into early detection of invasive species, and population trends and key ecological drivers for harvested populations and species of conservation concern in Norway.