of biological invasion occur where land-use change interacts 
with one or more additional drivers (established but 
incomplete) {3.5.1, 3.5.2, 3.5.3}. For example, interactions 
among land-use change, climate change and nutrient 
pollution have driven the introduction, establishment and 
spread of Pontederia crassipes (water hyacinth) across 
Africa (well established) {Box 3.12}. Extraction of natural 
resources is closely linked with major economic and 
demographic drivers and can lead to a range of wider 
ecosystem impacts, including habitat degradation and loss, 
which facilitates invasive alien species (well established)
{3.3.2, 3.4.2}. Climate change is predicted to lead to major 
changes in land- and sea-use and, in some regions, in 
human migration patterns (established but incomplete)
{3.3.4}, but also to more extreme events among natural 
drivers, such as droughts, floods, wildfires, tropical storms 
29SUMMARY FOR POLICYMAKERS
19SUMMARY FOR POLICYMAKERS
BACKGROUND
Box SPM 2 The International Convention for the Control and Management of Ships' 
Ballast Water and Sediments: an example of international collaboration to 
prevent biological invasions.