The Forest Specialist Index measures trends in the size of populations of threatened and non-threatened forest specialist vertebrate species. For the purpose of this indicator “forest specialists” are the species that live only in forest habitat, as opposed to forest generalists that live in forests but also occupy one or more other habitats.

The data can be used to assess if conservation actions are successful and if the status of forest species at the population level has changed. The underlying method is the same as for the global Living Planet Index so the indicator uses data that is of high temporal resolution and spatially explicit through being tied to a particular location. This allows for recording of metadata on local threats and conservation action and allows for disaggregation at different scales. Being based on annual changes in species populations on site level measures, the index is sensitive to annual change and reflects environmental conditions and impacts. Data sources and methods are publicly accessible online (www.livingplanetindex.org) and traceable.

Because the LPI data is site specific, it can be used in conjunction with the forest area indicator. The indicators can show the corresponding species abundance trends alongside changes in forest area for different regions.