causal factors of threat are likely to be more difficult to compare and to interpret.
The following sections of this chapter present in a series of maps the situation of threatened species by country as a percentage of the total number of each species group. Other species are threatened but could not be included because information is not complete. Because of this and the reasons given above, maps in the following section are likely to understate the situation. Due to different approaches by individual countries, direct comparisons between national data can be misleading, indicating the need for international harmonisation of species inventories.