Biological invasions
ð 20% group presentation oral exam (written preparation) 80%
ð Review papers are also part of the course (class is based on this more than on cursus)
Upon completion of the course a student must be able to:
• Explain invasion science.
• Outline the stages of the invasion process.
• Describe and critically evaluate the hypotheses to explain biological
• invasions.
• Summarize the effects of invasions on communities and ecosystems.
• List the possible management strategies for invasions and their pros and cons.
• Frame biological invasions within the science-policy interface
• Understand the added value of education and public awareness for successful
prevention and management of invasive species.
• Synthesize and critique about primary literature.
• Discuss literature with fellow scientists and orally present.
Topics
20/10: Invasion process and pathways of introduction
27/10: Invasiveness, invasibility and hypotheses on biological invasions
3/11: Impacts and impact assessment
10/11: Policy, risk assessment and management methods
17/11: Integrated management with biocontrol
24/11: Conflicts in management, outreach, and education on biological invasions
1/12: Guest speakers
15/12: student presentations
HOC 1:
1. Invasion process
2. Pathways of introduction
3. Trends in the number of invaders
4. Natural prehistoric vs. current biological invasions
5. Range shifts vs biological invasions
Intro to invasion science
An introduction to invasion science
= The study of the human mediated introduction of organisms, especially introductions
outside the potential range of given organisms as defined by their natural dispersal
mechanisms and biogeographical barriers
• Addresses all aspects relating to introduction of organisms, their ability to establish,
naturalize and invade in the target region and their interactions with resident
organisms in their new location
• Considers costs and benefits of their presence and abundance with reference to
human value systems
“The severe global threat posed by invasive alien species is underappreciated,
underestimated, and often unacknowledged”
, ð Comes from IPBES report from 2019, the first time that several scientists agreed that
invasive species are a problem, only in 2019, this is way too late, we realized it
IPBES report
In 2019, the IPBES (Intergovernmental Science-Policy Platform on Biodiversity and
Ecosystem Services) Global Assessment Report found that invasive alien species
are one of the five most important direct drivers of biodiversity loss – alongside
changes in land- and sea-use, direct exploitation of species, climate change and
pollution.
Based on this finding, Governments tasked IPBES to provide the best
available evidence and policy options to deal with the challenges of biological
invasions. The resulting report was produced by 86 experts from 49 countries,
working for more than four and a half years. It draws on more than 13,000
references, including very significant contributions from Indigenous Peoples and
local communities, making it the most comprehensive assessment ever carried
out of invasive alien species around the world.
You expect a Lot of media coverage: Made this first report, but it was not in the media
Invasive species are 2nd cause of biodiversity loss!
An underestimation, an undervaluation of this problem
Charles Elton: the Darwin of invasive species
• first book to examine the phenomenon (1958): the ecology of invasions by animals
and ants
• identified invasions as a threat to the world
• examined factors that promote or inhibit invasions
• recognised the importance of human activities in reshaping species distributions
• proposed hypotheses that are still being tested today
"biological invasions are so frequent nowadays in every continent and island, and even in the
oceans, that we need to understand what is causing them and try to arrive at some general
viewpoint about the whole business”
The ecology of invasion by animals and plants => its frequent happening everywhere, new
species coming and having an impact, we need to understand and find a solution
Proposed hypothesis
Some of the hypotheses still assess to today => very influential book
Graph: Quick view of how interest in invasion science has changed through time. No
citations until start of 90’s of papers that dealt with invasive species. Only 35 ys that this
field has been cited etc. This is a young brand of biology but rapidly growing, 2007 own
handbook is quite late.
Two graphs:
• Invasion biology/ecology/science is a young branch of biology, but rapidly growing as
the scientific interest in impacts and management has accelerated in the last
decades.
, • Own handbook (first edition 2007) : ‘Invasion Ecology’
• Covered in many high impact journals, but own journals too (biological invasions,
aquatic invasions, neobiota, management of biological invasions…)
impact factor increasing, more people getting involved in invasion biology
Field is very broad: ecology, evolution, biogeography of alien species, economic part (how
much does management costs), failures are harder to publish (we need to know if a
management technique doesn’t work tho! So it is not repeated, so try out and publish even
if it doesn’t work),….she listed more things
Focus:
• ecology, evolution and biogeography of non-indigenous aquatic and terrestrial
animals, plants, fungi and micro-organisms,
• mechanisms that drive the introduction, establishment and spread of these species,
• ecological, evolutionary, economic and other consequences of biological invasions,
• The management of invasions in any part of the world.
• papers on ethical, social, legal and policy issues related to biological invasions.
Social-ecological systems figure:
Invasive science vs invasive biology (only focuses on
organisms etc).
invasion science: at the interface of various scientific
disciplines: ecology, evolutionary biology, geography,
climatology, socio-political sciences, conservation
biology.
Various approaches: observational, experimental,
citizen-science, questionnaires, satellite data,
modelling, meta-analyses…
=> same methods as in other fields, more or less
BIOLOGICAL INVASION
Northern snakehead fish: Read the story of the northern snakehead fish (Channa argus)
this is how it starts: we find a species we don’t know yet; this ex is from 2000 and still going
on today. Bought by person that released it. Still happening today: people bring invasive
species in places. It is a top-down effect (predator fish). Even movie.
, Invasive range: invasive across the United States
Native range: native to China and possibly Korea and Russia
Introduction and spread:
• aquarium owners discarded their unwanted exotic captive species into local
waterways
• intentionally released into waterways to create a local food source for fisherman
Impact: top predator and disrupts the natural aquatic feeding structure in ecosystems
The arrival and spread of the Northern snakehead is a classical example of a biological
invasion
LETS DISCUSS
what is an invasive species: (vs alien species: not all alien species are invase effects)
Do they need to have an harmful effect? => maybe depends on human perception of
harmful
Quinten: alien species causes value loss => she does say there is a problem if it depends on
the people, no framework
Alien (can’t reproduce), exotic (can reproduce)
Quinten thinks invasive species must be able to reproduce
1 Invasion process
The wicked terminological web we weave: an alien species
non-indigenous species, exotic species, non-native species, introduced species, noxious …
= a species living outside its native distributional range, which has arrived there by human
activity, either deliberate or accidental
Alien species: invasion is process (not an event) with diff stages, terminology is important!!
Everyting invasive is always alien but not other way around
ð 20% group presentation oral exam (written preparation) 80%
ð Review papers are also part of the course (class is based on this more than on cursus)
Upon completion of the course a student must be able to:
• Explain invasion science.
• Outline the stages of the invasion process.
• Describe and critically evaluate the hypotheses to explain biological
• invasions.
• Summarize the effects of invasions on communities and ecosystems.
• List the possible management strategies for invasions and their pros and cons.
• Frame biological invasions within the science-policy interface
• Understand the added value of education and public awareness for successful
prevention and management of invasive species.
• Synthesize and critique about primary literature.
• Discuss literature with fellow scientists and orally present.
Topics
20/10: Invasion process and pathways of introduction
27/10: Invasiveness, invasibility and hypotheses on biological invasions
3/11: Impacts and impact assessment
10/11: Policy, risk assessment and management methods
17/11: Integrated management with biocontrol
24/11: Conflicts in management, outreach, and education on biological invasions
1/12: Guest speakers
15/12: student presentations
HOC 1:
1. Invasion process
2. Pathways of introduction
3. Trends in the number of invaders
4. Natural prehistoric vs. current biological invasions
5. Range shifts vs biological invasions
Intro to invasion science
An introduction to invasion science
= The study of the human mediated introduction of organisms, especially introductions
outside the potential range of given organisms as defined by their natural dispersal
mechanisms and biogeographical barriers
• Addresses all aspects relating to introduction of organisms, their ability to establish,
naturalize and invade in the target region and their interactions with resident
organisms in their new location
• Considers costs and benefits of their presence and abundance with reference to
human value systems
“The severe global threat posed by invasive alien species is underappreciated,
underestimated, and often unacknowledged”
, ð Comes from IPBES report from 2019, the first time that several scientists agreed that
invasive species are a problem, only in 2019, this is way too late, we realized it
IPBES report
In 2019, the IPBES (Intergovernmental Science-Policy Platform on Biodiversity and
Ecosystem Services) Global Assessment Report found that invasive alien species
are one of the five most important direct drivers of biodiversity loss – alongside
changes in land- and sea-use, direct exploitation of species, climate change and
pollution.
Based on this finding, Governments tasked IPBES to provide the best
available evidence and policy options to deal with the challenges of biological
invasions. The resulting report was produced by 86 experts from 49 countries,
working for more than four and a half years. It draws on more than 13,000
references, including very significant contributions from Indigenous Peoples and
local communities, making it the most comprehensive assessment ever carried
out of invasive alien species around the world.
You expect a Lot of media coverage: Made this first report, but it was not in the media
Invasive species are 2nd cause of biodiversity loss!
An underestimation, an undervaluation of this problem
Charles Elton: the Darwin of invasive species
• first book to examine the phenomenon (1958): the ecology of invasions by animals
and ants
• identified invasions as a threat to the world
• examined factors that promote or inhibit invasions
• recognised the importance of human activities in reshaping species distributions
• proposed hypotheses that are still being tested today
"biological invasions are so frequent nowadays in every continent and island, and even in the
oceans, that we need to understand what is causing them and try to arrive at some general
viewpoint about the whole business”
The ecology of invasion by animals and plants => its frequent happening everywhere, new
species coming and having an impact, we need to understand and find a solution
Proposed hypothesis
Some of the hypotheses still assess to today => very influential book
Graph: Quick view of how interest in invasion science has changed through time. No
citations until start of 90’s of papers that dealt with invasive species. Only 35 ys that this
field has been cited etc. This is a young brand of biology but rapidly growing, 2007 own
handbook is quite late.
Two graphs:
• Invasion biology/ecology/science is a young branch of biology, but rapidly growing as
the scientific interest in impacts and management has accelerated in the last
decades.
, • Own handbook (first edition 2007) : ‘Invasion Ecology’
• Covered in many high impact journals, but own journals too (biological invasions,
aquatic invasions, neobiota, management of biological invasions…)
impact factor increasing, more people getting involved in invasion biology
Field is very broad: ecology, evolution, biogeography of alien species, economic part (how
much does management costs), failures are harder to publish (we need to know if a
management technique doesn’t work tho! So it is not repeated, so try out and publish even
if it doesn’t work),….she listed more things
Focus:
• ecology, evolution and biogeography of non-indigenous aquatic and terrestrial
animals, plants, fungi and micro-organisms,
• mechanisms that drive the introduction, establishment and spread of these species,
• ecological, evolutionary, economic and other consequences of biological invasions,
• The management of invasions in any part of the world.
• papers on ethical, social, legal and policy issues related to biological invasions.
Social-ecological systems figure:
Invasive science vs invasive biology (only focuses on
organisms etc).
invasion science: at the interface of various scientific
disciplines: ecology, evolutionary biology, geography,
climatology, socio-political sciences, conservation
biology.
Various approaches: observational, experimental,
citizen-science, questionnaires, satellite data,
modelling, meta-analyses…
=> same methods as in other fields, more or less
BIOLOGICAL INVASION
Northern snakehead fish: Read the story of the northern snakehead fish (Channa argus)
this is how it starts: we find a species we don’t know yet; this ex is from 2000 and still going
on today. Bought by person that released it. Still happening today: people bring invasive
species in places. It is a top-down effect (predator fish). Even movie.
, Invasive range: invasive across the United States
Native range: native to China and possibly Korea and Russia
Introduction and spread:
• aquarium owners discarded their unwanted exotic captive species into local
waterways
• intentionally released into waterways to create a local food source for fisherman
Impact: top predator and disrupts the natural aquatic feeding structure in ecosystems
The arrival and spread of the Northern snakehead is a classical example of a biological
invasion
LETS DISCUSS
what is an invasive species: (vs alien species: not all alien species are invase effects)
Do they need to have an harmful effect? => maybe depends on human perception of
harmful
Quinten: alien species causes value loss => she does say there is a problem if it depends on
the people, no framework
Alien (can’t reproduce), exotic (can reproduce)
Quinten thinks invasive species must be able to reproduce
1 Invasion process
The wicked terminological web we weave: an alien species
non-indigenous species, exotic species, non-native species, introduced species, noxious …
= a species living outside its native distributional range, which has arrived there by human
activity, either deliberate or accidental
Alien species: invasion is process (not an event) with diff stages, terminology is important!!
Everyting invasive is always alien but not other way around
