C18 When prevention fails or is not possible, 
preparedness, early detection and rapid response 
are effective at reducing rates of invasive alien 
species establishment in terrestrial and closed 
water systems, and critical for marine and 
connected water systems (well established) {5.4.2, 
5.5.1, 5.5.3, 5.5.2, 5.6.3.3}. Horizon scanning and risk 
analysis are examples of the many decision-support tools 
used to identify and prioritize emerging invasive alien 
species to support preparedness (well established) {5.2}. 
Such tools can inform the development of rapid response 
plans in advance of an incursion to guide action effectively 
following the detection of priority invasive alien species (well 
established) {5.2.2.1.a, 5.2.2.1.b, 5.5.1}. Early detection of 
invasive alien species can enable rapid intervention to 
contain and eradicate invasive alien species before they 
spread (well established) {5.1.1, 5.3.1.1, 5.5.2}. General 
surveillance strategies (e.g., through citizen science, sentinel 
sites, and remote sensing) for detecting new invasive alien 
species can also underpin effective preparedness 
(established but incomplete) {5.3.1.1, 5.4.2.1.a, 5.4.2.2.a, 
5.5.2, Box 6.20}. For example, in Africa, Asia and Latin 
America, the PlantwisePlus programme assists smallholder 
farmers with the identification of pests and damaged crops, 
contributing to early detection of invasive alien species 
outbreaks (well established) {5.5.2}.
SUMMARY FOR POLICYMAKERS
19SUMMARY FOR POLICYMAKERS
BACKGROUND
Table SPM 1 Objectives and actions for managing biological invasions. 