Faculty of Sciencee and Technology
University of Bolzano,
B
Bolzano
Italy
Bolzano, 14.12.2010
“Invasive Ex
xotic Species”
Asst.. Prof. Seergio Angeli
Asst
Insect Che
emoecology
Why worry about Exxotic (Alien) species?
Value of exotic species
•It
It has
h been
b
estimate
ti t th
h t in
hat
i USA exotic
ti species
i
produce 98% of food su
upply, equal to 500 billion
d ll
dollars
•Only
O l some exotic
ti specie
ies become
b
i
invasive
i
Invasivee Species
•Definition:
“Invasive
Invasive species
species” means an alien sp
pecies whose introduction does or is
likely to cause economic or environm
mental harm or harm to human
health. USA Executive Order 13112 (Feb. 3, 1999)
• The “10 percent rule”, 0.1% of
o alien species that arrive
become invasive
- 10 % of the arriving ones establish
h in the new natural environment
(=10% )
- 10 % of the establishing ones spreaad in the new natural environment
(=1%)
-10 % of the spreading ones become invasive
(=0.1%)
Cost of Invaasive species
Invasive species cause econ
nomic damage:
-About ¼ of agricultural GNP is
i lost because of agricultural
p
pests
- In USA ca. 120- 140 billion doollars are lost annually because
of invasive species
- Costs eexcludes
cl des damage to natural
ral ecos
ecosystems
stems
How do invasive speecies cause damage?
Invasive species cause damage
d
by:
-Eliminating indigeno
ous species
-Disrupting ecosystem
m processes
-Reducing biodiversitty
- Cause
C
h
human h
health
lth
h or economic
i problems
bl
How do invasive sspecies get here?
Why are invasive species
s
successful?