GCI2016: Lecture: Global changes and biological invasion of alien species - Yury Dgebuadze

Lecture: Global changes and biological invasion of alien species
Yury Dgebuadze (International Union of Biological Sciences, A.N. Severtsov Institute of
Ecology and Evolution and Russian Academy of Science)
The biological invasion of alien species as establishment of species population
outside of their native range dramatically intensified in the end of the ХХ century. Thus
biological invasion is not only intentional introduction valuable species and accidental
introduction with traffic, ballast waters etc., but self-spreading of species because the
climate and density changes and anthropogenic destruction of native ecosystems.
In global scale biological invasions of alien species cause biota homogenization when
as a result both taxonomic (set of species) and ecological (set of ecological guilds,
communities and ecosystems) diversity are changing in many regions. In local scale
ecosystems transformation and sometimes degradation are observed. The last occurrence
connects with ecosystem persistence loss to any influences including natural changes.
Natural biological resources such as forest resources, water resources, pasturable
resources, and game resources, which exploited by humans in extensive way in such
transformed ecosystems sharply decreased. Alien species, which have cause and transmit
diseases or consume other organisms bring decline of biological production in artificial
ecosystems also.
The studies revealed that vulnerability of ecosystems to alien species introduction is
one of the least studied and the most difficult questions. However, from the data obtained it
is possible to assume that an ecosystem primary production growth and pressure of
predators make the system more vulnerable when aboriginal competitors and parasites
block invasions. Biological invasion process supposes that introduced species on the one
hand have to adapt to new climate of the region of introduction and on the other hand
discomfort aboriginal species. This allows presuming corresponding alterations in the
regulation of the vulnerability of ecosystems to invasions. Under climate warming
ecosystems are more vulnerable because of the primary production growth when the role of
aboriginal species in the regulation process lowers as many of them are discomforted. It is
obvious that introduced species from the warmer climatic zones receive a competitive
advantage. Data obtained during the last two decades in Eurasia confirm the correctness of
these assumptions. The analysis of the introduced species composition showed that
southern species predominate in many places of this continent. Global change as sum of
climate change and human impact promotes the invasion process through the growth of
primary production of ecosystems and ecological regulation of their vulnerability to alien
species invasions.
Many cases show that alien species invasions can nullify attempts to use ecosystems
or keep them from destruction. Insect pests, weed and allergen plants; rodents and some other mammals have already done severe damage to both artificial and natural ecosystems.
Some of them maintain and spread natural foci of diseases.
International Union of Biological Sciences (IUBS) promotes international
collaborations in this field among different countries, by organizing special program:
Biological Consequences of Global Change (BCGC), symposia, workshops and trainings.