Isnīt the Farmland Bird Indicator incomplete or even deceptive, as it may go unnoticed that certain species decline and may run the risk to become extinct? How can we solve this problem?
AnswerThe Farmland Bird Indicator aims to give a general description of changes in bird populations. It is indeed possible that some bird species decline when the indicator is stable or goes up. Such a decline may be temporarily, due to natural fluctuations, but it may also be persistent, meaning that a species becomes endangered and deserves special attention. For this reason, PECBMS not only publishes multispecies indicators, but also yearly supranational trends of individual species. As our indicator doesnīt capture all changes in biodiversity, which no single metric can, we also recommend adding a Red List indicator to summarize if the number of threatened species in a country is increasing or decreasing over time (see Butchart et al., 2005).
Learn more in the related question "If a species becomes extinct (or undetectable by the monitoring scheme because it is becoming very rare), does it also disappear from an indicator?".