management approach, including ecosystem restoration, 
depends on long-term monitoring to assess management 
efficacy using ecological and social indicators (established 
but incomplete) {5.5.2, 6.6.3}. Long-term monitoring of sites 
ensures early detection of new introductions, reintroductions 
and re-emergence of invasive alien species (e.g., from a 
seed bank that includes invasive alien plants) and can inform 
further management actions (well established) {5.4.3.3.b, 
5.5.6}. However, most studies failed to quantify the 
effectiveness of ecosystem restoration since they failed to 
measure the initial status of native vegetation. This has led 
to inconsistent conclusions regarding the best invasive alien 
plant control option which may lead to the most effective 
ecosystem restoration {5.4.3.3b; 5.5.6}. Regarding 
freshwater ecosystems, monitoring biodiversity using 
macroinvertebrate-based indices is a widely used method 
globally. However, knowledge is lacking on how invasive 
alien species may affect the metric scores and therefore 
classification of a river's status (established but incomplete)
{5.6.2.3}. In marine and connected water systems, 
ecosystem restoration has so far proved to be largely 
ineffective because the systems are open, leading to 
difficulties in implementing and evaluating management 
actions (established but incomplete) {5.5.6, 5.6.1.1}.
SUMMARY FOR POLICYMAKERS
19SUMMARY FOR POLICYMAKERS
BACKGROUND
Box SPM 4 Working for Water programme: an example of management of invasive alien 
species leading to recovery of nature's contributions to people.