IUCN recently published guidelines for Red List of Ecosystems (RLE) risk assessment . The RLE criteria include consideration of changes in an area and the geographic distribution of ecosystems but also of changes in the biotic and abiotic ecological quality of ecosystems. In widely distributed ecosystems, such as boreal forests in Finland, ecological quality is often more important than the spatial extent of an area in assessing threat status. Therefore, it is important to find quantitative variables that are good surrogates for the overall quality of an ecosystem.
In the RLE assessment of Finland, we divided boreal forests into 40 ecosystem types. Of these, forests with mineral soils (19 types) have a greater spatial extent than all other terrestrial ecosystem types in total (c. 300 types). We classified these forest types based on fertility, successional stage (young, mature and old) and dominant tree species (conifer or deciduous). For the assessment of their biotic quality, we used the data provided by the Finnish National Forest Inventories (NFI) which include several variables that can be used in the RLE assessment of forest ecosystems. Of them, we selected three: dead wood (m3/ha), large trees (number of trees/ha) and deciduous trees (% of volume of living trees). Following the IUCN guidelines, we calculated the relative severity of changes for each variable based on the present values and the reference values (50 years ago; RLE criterion D1) within each ecosystem type. The Red List category of the ecosystem type was based on the average of the severities of the changes in variables. For meeting also the RLE criterion D3 (reference year c. 1750), the historical values of dead wood and large trees were estimated based on expert opinions.
The RLE assessment in Finland was carried out at the national scale and separately for the northern and southern parts of Finland. For the forest types, we made the regional assessments first and from them calculated the average Red List categories at the national scale, weighted by the areas of each ecosystem type in northern and southern parts. The final report will be published by the end of 2018.
We highly encourage the use of the representative and continuously updated NFI data for RLE assessments whenever possible.
 IUCN 2017. Guidelines for the application of IUCN Red List of Ecosystems Categories and Criteria, Version 1.1. Bland, L. M., Keith, D. A., Murray, N. J., and Rodríguez, J. P. (eds). Gland, Switzerland: IUCN. 99 pp.