b3alien: Target 6 indicator
Indicator type
indicator to evaluate policy
Explanation
This headline indicator, calculated by applying the b3alien package, estimates the actual rate at which new invasive alien species (IAS) successfully establish permanent populations within a region. It screens wildlife observations against international alien checklists to track the speed of biological invasions:
- A fast-rising establishment rate implies that more non-native species are successfully breeding, surviving, and setting up permanent populations in the area.
- A low or decreasing establishment rate indicates that fewer new alien species are managing to gain a permanent foothold in the local ecosystem.
Applicability for policy
This metric serves as the official CBD Headline Indicator to monitor global and national progress toward Target 6 of the Kunming-Montreal Global Biodiversity Framework. Its direct policy goal is to reduce the introduction and establishment rates of known invasive species by at least 50% by 2030. Especially looking at this at longer time scales (as is suggested in the CBD documentation) can provide some insight in the effectiveness of policies.
Limitations
As a high-level headline indicator, it simplifies highly complex ecological processes into a single, generic number. It is highly sensitive to regional data gaps and uneven mapping across different species groups. Therefore, this metric must always be interpreted alongside local maps and expert ecological assessments. Importantly, basic measures for observation effort and special bias can also be retrieved from the package b3alien.
