THE THEMATIC ASSESSMENT REPORT ON INVASIVE ALIEN SPECIES AND THEIR CONTROL
16SUMMARY FOR POLICYMAKERS
for eradication programmes but they are generally more 
cost-effective than long term and permanent control or the 
costs incurred through inaction.
KM-C4 Containment and control can be an 
effective option for invasive alien species that 
cannot be eradicated for various reasons from 
terrestrial and closed water systems, but most 
attempts in marine and connected water systems 
have been largely ineffective {C20}. Physical control 
alongside chemical control options in terrestrial and closed 
water systems are generally only effective at a local scale 
and can have non-target effects. Biological control can be 
applied for widely distributed invasive alien species and has 
been successful in managing some invasive alien plants, 
invertebrates and, to a lesser extent, plant pathogenic 
microbes and vertebrates, but it may also have non-target 
effects if not well regulated. International standards and 
risk-based regulatory frameworks for biological control have 
been used in many countries to manage risks, and continue 
to be successfully applied. Integrated management, where 
more than one containment or control option are used, can 
improve outcomes.
KM-C5 The recovery of ecosystem functions 
and nature's contributions to people can be 
achieved through adaptive management, including 
ecosystem restoration in terrestrial and closed 
water systems {C21}. Management outcomes can be 
improved by the integration of site- and/or ecosystembased management options that enhance ecosystem 
function and resilience. Frequent long-term monitoring 
of sites ensures early detection of invasive alien species, 
including re-invasions, and can inform further management 
actions. In marine and connected water systems, 
ecosystem restoration has so far proved to be largely 
ineffective. Adaptive management, possibly combining 
multiple options, will improve management of biological 
invasions under ongoing climate and land-use change. 
Integrating site and/or ecosystem-based approaches can 
improve management outcomes of biological invasions and 
also enhance ecosystem functioning under ongoing climate 
and land-use change.
KM-C6 Engagement and collaboration with 
stakeholders and Indigenous Peoples and local 
communities improve outcomes of management 
actions for biological invasions {C23, C24}. Engaging 
stakeholders, including the private sector, and Indigenous 
Peoples and local communities in the collaborative 
management of biological invasions is important for social 
acceptability and improving environmental, social and 
economic outcomes, particularly where there are conflicting 
perceptions of the value of invasive alien species and the 
ethics of management options. Management actions also 
benefit from sharing and collaboration across knowledge 
systems. Recognizing Indigenous Peoples' and local 
communities' knowledge, rights and customary governance 
systems in accordance with national legislation also helps to 
improve long-term management.
D. Ambitious progress to 
manage biological invasions8
can be achieved with integrated 
governance
One of the greatest threats to biodiversity, 
invasive alien species can be overcome 
through a context-specific integrated 
governance approach to biological invasions, 
including well-resourced, coordinated and 
sustained strategic actions, with closer 
collaboration across sectors and countries. 
Managing biological invasions is realistic 
and achievable, with substantial benefits for 
nature and people. 
KM-D1 Through a complementary set of strategic 
actions, integrated governance can limit the global 
problem of invasive alien species throughout the 
biological invasion process and at local, national 
and regional scales {D25}. Strategic actions to prevent 
the introduction and impact of invasive alien species 
include: enhancing coordination and collaboration across 
international and regional mechanisms; developing and 
adopting effective and achievable national strategies; 
sharing efforts and commitment and understanding the 
specific role of all actors; improving policy coherence; 
broad engagement across all stakeholders and Indigenous 
Peoples and local communities; resourcing innovation, 
research and technology; and supporting information 
systems, infrastructures and data sharing.
KM-D2 The threat of invasive alien species 
could be reduced with closer collaboration and 
coordination across sectors and countries to 
support the management of biological invasions 
{D26, D30} (Figure SPM.7). International, national 
and local agencies involved in developing policies for the 
environment, agriculture, aquaculture, fishing, forestry, 
horticulture, border control, shipping (including biofouling), 
tourism, trade (including online trade in animals, plants, and 
other organisms), community and regional development 
(including infrastructure), transportation and the health 
sector can all play a role in developing a coherent approach 
8. This assessment acknowledges that national and local legislation to 
address biological invasions differ between countries and may include 
different definitions appropriate to specific national and local contexts.
SUMMARY FOR POLICYMAKERS
The thematic assessment report on
INVASIVE ALIEN SPECIES
AND THEIR CONTROL
TIC ASSESSMENT REPORT ON INVASIVE ALIEN SPECIES AND THEIR CONT