Biological invasions: The Unseen Threat

Climate & Environment

Franck Courchamp

Ecologist and Research Director at the CNRS Institute AXA Chair in Invasion Biology at the University of Paris-Saclay

We have all heard about climate change.

Pollution, habitat destruction, overfishing and deforestation. You will also be aware of these environmental threats.

But have you ever heard of biological invasions? These pose a major threat to our environment, but one that remains under most people’s radar. I'm talking here about invasive alien species: plants and animals of every kind from distant countries that, once established in a new territory, wreak havoc on local ecosystems.

With Dr. Franck Courchamp, discover what we can do collectively to combat this little-known threat. Because you also have the opportunity to play a decisive role. 

What you will learn

  • What are these so called “invasive species”

  • How their spread is threatening our ecosystems

  • The financial impact of biological invations

  • What we can do to reverse the course of invasions

19mn | Video

The masterclasss in 3 main chapters

Chapter 1

When worlds collide: the rise of invasive alien species

05:42 | Video

1.1 The enemy with a thousand names 
What is an invasive species and what impact does it have on the ecosystem it invades? In today’s globalized world where goods and people travel freely, many species are transported across continents to habitats they could never previously have accessed.

1.2 From ship's rats to ballast water: a brief history of invasive species 
The introduction of exotic species resulted in biological invasions right around the world ever since we began to explore it. All it takes to change the course of things is a single shipment…

1.3 The recent acceleration in biological invasions
Climate change is drastically accelerating the number of biological invasions. Territories that were once protected by climatic barriers are now open to species that are able to survive there all year round. 

Chapter 2

Silent and underestimated: the triple threat of invasions

04:17 | Video

2.1 The second leading cause of species extinction
So what's the problem with species traveling from elsewhere and establishing themselves in new territories? Quite simply because a species that invades an ecosystem new to it does so at the expense of an existing species.

2.2 A threat to human health
While parenthood has no impact on men’s careers, it has negative repercussions on women’s careers. This is what economists call the “child penalty” or the “family gap”.

2.3 More expensive than earthquakes and tornadoes
By way of comparison, and as surprising as it may seem, biological invasions are more costly than earthquakes or tornadoes. But why are biological invasions so costly? 

Chapter 3

How to reverse the course of invasion

07:12 | Video

2.1 Fighting back against living things to protect living things
Fighting back against biological invasions often seems counter-intuitive, because it means us taking action against living things to preserve biodiversity. Fighting back against invasive species means making difficult decisions, including the elimination of an entire population.

2.2 Prevent, respond, control... or suffer the effects.
As the old adage goes “prevention is better than cure”, but we could usefully add that it's better to apply that cure at the earliest opportunity, because then it's much more effective. Implementing preventive measures is always costly, but inaction is even more expensive…

2.3 From technology to education: a broad range of solutions
Fortunately, it is now possible to control and prevent biological invasions, and technology is a major ally. 


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