Transcript Invasions

Invasion species
Sapozhnikova Elena
Invasions are processes of the penetration of
alien species into ecosystems located outside
their natural areas and their impact to the native
communities.
Invasions can be caused by:



natural migrations of organisms by climatic changes
and fluctuations of population abundance
introduction of the economically useful organisms
accidental drift with ballast water, agricultural
products etc
The types of invasion species
influences on native species:


alien species can essentially change habitat
of indigenous species
invasion species can become superior
competitors, predators or pathogens for
native species and promote their replace
G. fasciatus is successful invader from Lake
Baikal.
1989
1989
1986
1986
1988
1988
1986
1986
1969
1977
1969
1973
1964
1968
1967
The main factors, which promoted replacement
of Gammarus lacustris by Gmelinoides fasciatus
in Lake Ladoga



G. fasciatus is superior competitor for food
G. fasciatus has shorter generation time and higher
productivity
G. fasciatus has a higher ability to avoid the fish
predation
Gammarus lacustris
Gmelinoides fasciatus
The ways of invasion prevention
careful studying of the influence of alien
species on native species at all levels
 toughening of the customs inspections
 informing of the population about possible
danger

Thank you for your attention!