Introduced species and biodiversity

Summary

The video script delves into the complexities of introducing new species to ecosystems, highlighting the unintended consequences that can arise from both intentional and accidental introductions. It underscores the economic and ecological impact, with an annual cost of $1.4 trillion to the world economy. The script also discusses the concept of native habitats, the role of collections in preserving historical information, and the competitive advantages invasive species have due to lack of natural controls. Examples such as comb jellies in the Black Sea and Dutch Elm disease illustrate the devastating effects of invasive species on native populations and ecosystems, emphasizing the need for human intervention to mitigate these impacts.

Takeaways

• 🌱 Introducing new species to an area can seem like a good idea for increasing biodiversity, but it's more complex than simply adding species richness.
• 🌿 Introduced species, also known as exotic species, are those transferred by human activities to an area where they don't naturally occur.
• 🐄 Many species introductions are intentional, often for agricultural purposes, and have been happening since humans realized they could transport organisms.
• 🚢 Accidental introductions often occur alongside human activities, bringing along parasites and other organisms that can disrupt local ecosystems.
• 💸 Introduced species have a significant economic impact, costing the world economy 1.4 trillion dollars annually to manage their negative effects.
• 🔍 The concept of native habitat is complex due to the long history of human-induced species transfers, with some species' introduction history being unknown or 'cryptogenic'.
• 📚 Collections of species are vital for preserving historical information and establishing baselines to trace the origins of species introductions.
• 🍎 Not all introduced species are harmful; some provide new food sources or habitats and can be beneficial to native species.
• 🐍 Some introduced species become invasive due to competitive advantages and lack of natural controls, leading to negative impacts on native populations.
• 🌊 Invasive species can cause a cascade of ecological disruptions, altering food webs and reducing ecosystem function, as exemplified by the comb jelly in the Black Sea.
• 🦠 Invasive species can also include pathogens, which can lead to extinctions and have far-reaching effects on dependent species and ecosystems.

Q & A

What is the term 'introduced species' synonymous with?

The term 'introduced species' is synonymous with 'exotic species', referring to any species that has been knowingly or accidentally transferred by human activities from its native habitat to one where it doesn't naturally occur.

What is the main difference between an introduced species and a native species?

An introduced species is one that has been moved by human activities to an area where it doesn't naturally occur, while a native species is one that occurs naturally in an area without human intervention.

Why do humans intentionally introduce species to new areas?

Humans intentionally introduce species to new areas primarily for agricultural purposes, such as for food production or to serve other beneficial uses.

What are some examples of accidental introductions of species?

Examples of accidental introductions include rats coming off ships and snakes arriving in Guam with military movements during World War Two, both of which had significant negative impacts on native bird populations.

What is the annual cost to the world economy due to the negative impacts of introduced species?

The annual cost to the world economy due to the negative impacts of introduced species is 1.4 trillion dollars.

What does the term 'cryptogenic species' refer to?

Cryptogenic species refers to species for which the history of their introduction is uncertain or unknown, with 'crypto' meaning hidden and 'genic' referring to origin.

How can collections help in understanding the origins of introduced species?

Collections can preserve historical information about what species were present in an area beforehand, establishing baselines for future reference and helping to trace the origins of introductions.

Can introduced species sometimes have a positive impact on native species?

Yes, some introduced species can provide new food sources or habitats for native species, and native species can sometimes make use of the newcomers.

What are the characteristics of invasive species?

Invasive species are those that have competitive advantages, lack natural controls such as predators or diseases, and can reproduce rapidly and thrive in a wide range of environmental conditions, often overwhelming native populations.

What is the difference between introduced species and invasive species?

All invasive species are introduced, but not all introduced species are invasive. Invasive species are those that take over an environment at the expense of native species, causing significant harm to the ecosystem.

Can you provide an example of how an introduced species can cause a collapse in an ecosystem?

In 1992, an introduced species of comb jelly in the Black Sea led to the total collapse of the anchovy fishery due to the comb jellies' voracious appetite for fish larvae and eggs, demonstrating how introduced species can drastically alter ecosystems and food webs.

How do invasive species affect ecosystem function and why is it important to control them?

Invasive species can cause decreases in ecosystem function by outcompeting natives for resources, altering food webs, and introducing new diseases or parasites. Controlling them is crucial not only for moral reasons but also because these invasives can harm species we depend on and disrupt healthy ecological functions essential for all life, including humans.