A1 More than 37,000 established alien species, 
including more than 3,500 invasive alien species 
with documented impacts, have been recorded 
worldwide (well established) {2.1.4, 4.2}. Alien 
species (plants, animals, fungi and microorganisms, 
including pathogens) are being introduced globally at an 
unprecedented rate; currently, approximately 200 new alien 
species are recorded every year (well established) {2.2.1}. 
Invasive alien species represent a subset of alien species, 
consisting of those that have established and spread and 
are known to have a negative impact on nature and, in 
some cases, people (Figure SPM.1). Although their 
numbers are likely to be underestimated and expected to 
increase, to date 1,061 alien plants (6 per cent of all 
established alien plants), 1,852 alien invertebrates (22 per 
cent), 461 alien vertebrates (14 per cent) and 141 alien 
microbes (11 per cent) are known to be invasive globally 
(established but incomplete) {4.2}. Although some invasive 
alien species can provide benefits for people (e.g., through 
provision of food and fibre), those benefits do not mitigate 
or undo their negative impacts on nature, nature's 
contributions to people, and good quality of life across all 
regions and taxa globally (well established) {1.3.4, 4.1.2, 
4.3, 4.4, 4.5}. In addition to their impacts on nature, about 
16 per cent of invasive alien species have negative impacts 
on nature's contributions to people, and about 7 per cent 
on good quality of life (Figure SPM.2) (established but 
incomplete) {4.2}. Based on data and information included 
in this assessment, most impacts are reported in the 
Americas (34 per cent), Europe and Central Asia (31 per 
cent) and Asia-Pacific (25 per cent), with fewer reported in 
Africa (7 per cent) (established but incomplete) {4.2}. 
Twenty per cent of all impacts are reported from islands 
(established but incomplete) {4.2}. A disproportionate 
number of documented negative impacts have been 
reported from the terrestrial realm (75 per cent), especially 
temperate and boreal forests and woodlands and cultivated 
areas (including agricultural land) (established but 
incomplete) {Table 4.2}. About one quarter of the 
documented negative impacts have been reported from 
aquatic realms (freshwater: 14 per cent; marine: 10 per 
cent), especially from inland surface waters/waterbodies 
and shelf ecosystems (established but incomplete)
{Table 4.2}.
A2 Invasive alien species are a major direct driver 
of change, causing biodiversity loss, including local 
 <Section-header> A. Invasive alien species are a major threat to nature, 
nature's contributions to people, and good quality of li </Section-header> 

SUMMARY FOR POLICYMAKERS
19SUMMARY FOR POLICYMAKERS
BACKGROUND
A. Invasive alien species are a major threat to nature, 
nature's contributions to people, and good quality of li