Lecture 6 - guest lecturer Flashcards
What defines an alien invasive species (AIS)?
a) A native species that becomes dominant in its habitat
b) A species introduced accidentally or deliberately with no negative impacts
c) A species introduced outside its native range, causing significant negative effects
d) A species naturally migrating to a new habitat due to climate change
c) A species introduced outside its native range, causing significant negative effects
Explanation: AIS are defined by their introduction into non-native environments and their harmful ecological, economic, or social impacts.
Which of the following is NOT a common method of AIS introduction?
a) Ship ballast water
b) Construction of canals
c) Natural migration across oceans
d) Pet trade
c) Natural migration across oceans
Explanation: Natural migration is not a form of human-facilitated AIS introduction, unlike ballast water or the pet trade.
Explain the concept of “sleeper populations” in invasive species ecology.
Sleeper populations persist at low levels until triggered by an environmental shift, causing rapid population growth and ecosystem disruption.
Explanation: These populations represent a form of invasion debt, where impacts occur long after initial introduction.
Describe the role of ship ballast water in AIS introduction.
Ballast water taken up at one port often contains aquatic organisms, which are released at another port, introducing non-native species.
Explanation: This unintentional mechanism has facilitated the spread of species like the Chinese mitten crab.
What are the ecological impacts of the invasive American bullfrog?
The bullfrog preys on native species, competes for resources, and spreads diseases like chytrid fungus and rana virus.
Explanation: Its generalist diet and disease carrier status make it a significant threat to amphibian biodiversity.
How do biocontrol agents sometimes exacerbate invasive species problems?
Poorly chosen agents, like the cane toad, can fail to control the target species and instead disrupt local ecosystems.
Explanation: Introducing non-native predators or competitors may result in unintended ecological consequences.
Discuss the long-term ecological effects of Japanese knotweed on riparian ecosystems.
Japanese knotweed alters soil chemistry, disturbs nutrient cycling, and increases erosion and flooding risks, disrupting native plant and aquatic communities.
Explanation: Its extensive rhizomes and competitive dominance exacerbate these impacts.
Evaluate the effectiveness of functional eradication in managing AIS populations.
Functional eradication reduces population densities below damaging levels rather than complete removal, making it effective in high-priority habitats.
Explanation: This strategy balances ecological impact mitigation with the practical challenges of complete eradication.
Analyze the role of colonial history in shaping global AIS distributions.
Colonial trade routes and resource extraction facilitated the spread of species, resulting in lasting ecological similarities among previously colonized regions.
Explanation: Historical human activities created pathways for species introduction, evident in today’s global flora and fauna distribution.
Case Study: Cane Toad in Australia
Why was the cane toad introduced, and what were the consequences?
Introduced for biological pest control, the toad failed to control pests and became a highly invasive species, preying on and poisoning native fauna.
Explanation: This case highlights the risks of introducing non-native species without thorough ecological assessment.
Case Study: Pablo Escobar’s Hippos in Colombia
What are the ecological and social challenges posed by this invasive population?
The hippos alter aquatic ecosystems and pose safety risks, while their charisma complicates culling efforts.
Explanation: This example demonstrates how public perception can influence invasive species management.
Case Study: Zebra Mussels in North America
How have zebra mussels impacted aquatic ecosystems and infrastructure?
They clog water intake systems, outcompete native mussels, and alter food webs, causing significant economic and ecological harm.
Explanation: Their rapid reproduction and biofouling behavior create widespread impacts.
How does the Biotic Resistance Theory relate to AIS management?
It suggests that species-rich native ecosystems are more resistant to AIS due to reduced niche availability.
Explanation: Promoting biodiversity can serve as a preventative measure against invasions.
What factors influence whether an introduced species becomes invasive?
Factors include environmental compatibility, reproductive traits, absence of predators, and human activities.
Explanation: These factors determine the establishment and spread of introduced species.
Why is early detection and rapid response critical in AIS management?
Early interventions prevent population establishment, minimizing long-term ecological and economic impacts.
Explanation: Proactive measures are more cost-effective and reduce damage compared to delayed responses.
Compare manual removal and biological control as AIS management strategies.
Manual removal involves physically capturing or removing invasive species, while biological control uses natural predators or pathogens to suppress invasive populations.
Explanation: Manual removal can provide immediate population reduction but may be labor-intensive and inefficient in inaccessible habitats. Biological control can be cost-effective over time but carries the risk of unintended ecological impacts, such as affecting non-target species.
How does climate change amplify the risks of biological invasions?
Climate change creates new suitable habitats for invasive species, alters native species’ resilience, and disrupts ecological balances, facilitating invasions.
Explanation: As temperature, precipitation, and other environmental conditions shift, species once limited by climate may expand their ranges, outcompeting native species and creating cascading ecosystem effects.
What are the economic implications of invasive species for global agriculture and infrastructure?
Invasive species damage crops, spread pests and diseases, clog water systems, and degrade infrastructure, leading to billions of dollars in annual economic losses.
Explanation: Examples like zebra mussels and invasive carp demonstrate how invasions increase maintenance costs, reduce agricultural yields, and disrupt ecosystem services crucial for economic stability.
Discuss how eDNA technology aids in monitoring and managing AIS.
Environmental DNA (eDNA) allows for non-invasive detection of AIS by analyzing genetic material in water, soil, or air samples, enabling early detection and mapping of populations.
Explanation: eDNA is highly sensitive and can identify species presence even at low densities, making it a powerful tool for monitoring, assessing invasion risks, and guiding targeted management interventions.
Analyze the role of public participation in AIS eradication efforts, using lionfish derbies as an example.
Public participation, such as in lionfish derbies, mobilizes local communities to remove invasive species through organized events, increasing removal efficiency and awareness.
Explanation: These initiatives combine ecological management with education and recreation, fostering community involvement and reducing invasive populations in high-priority areas, such as coral reefs.
