Species Invasions Lecture Review

A collection of flashcards based on lecture notes discussing species invasions, their impacts, and control strategies.

What is an Alien/Exotic/Introduced species?

A non-native species found outside the range where the species evolved.

What does Native/indigenous refer to?

Species that were present prior to European colonization.

What is meant by Naturalized species?

Non-native species that are well adapted to the local environment and have been present for a long time.

Define Invasive/Invader species.

Non-native species that spread rapidly and severely affect native species.

What does Endemic mean in ecology?

A species that is native and found only in one specific location or region.

What framework is proposed for understanding the invasion process?

The invasion process can be divided into stages with barriers to be overcome.

What are the key questions to address in the invasion process?

1) What are their impacts? 2) What factors influence success? 3) How are species introduced? 4) Control or prevention of invasions.

How many non-native plant species are found in NA prairies?

11% of plants in NA prairies are non-native.

What percentage of vertebrates worldwide are threatened by exotic species?

20% of all endangered vertebrates are threatened by exotics.

What example illustrates the increase in the rate of accumulation of introduced species?

In San Francisco Bay, from 1851-1960 there was 1 introduction every 55 weeks, while from 1961-1995 it increased to 1 every 14 weeks.

What were some intentional introductions of species?

Livestock, crops, sport fishing/hunting, pet/aquarium trade.

What significant economic damage has resulted from invasive species?

Eurasian zebra mussel ($100M/yr), Eurasian gypsy moth ($11M/yr), Eurasian shipworm ($200M/yr).

What public health threats are associated with species introductions?

Smallpox, avian and human malaria, cholera, ebola, bird flu.

How can invasive species impact biodiversity?

Impacts can be good or bad depending on context; they may increase richness in empty niches or threaten native species.

What are direct and indirect effects of an invader?

Direct effects are interactions like competition and predation, indirect effects include trophic cascades and habitat modifications.

What was a major consequence of the invasion by the brown tree snake in Guam?

The explosion of its population led to the gradual disappearance of native birds.

What is considered a significant threat to other islands due to introduced predators?

Predation from species like the introduced wolf snake which led to species extinctions such as the Christmas Island Blue-tailed Shinning-skink.

What are some infamous invasive predators?

Giant African snail introduced to Hawaii, Nile perch in Lake Victoria.

What are the impacts of introduced competitors?

They can cause population extirpations, disrupt local ecosystems and depend on competition and predation.

How has the Argentine ant impacted native ecosystems?

It competes with native ants and preys on insects, affecting survival rates of birds and small mammals.

What are some morphological impacts invaders can have on native species?

Invaders can cause changes in the behavior or morphology, such as developing thicker shells in response to predation.

What can hybridization with introduced species lead to?

It can alter native species' fitness or create aggressive/competitive hybrids.

What broader ecosystem impacts can invaders have?

They can alter habitat structure, disturbance regimes, and nutrient cycling.

How can we predict the relative impact of an invader?

Using the index I = RxAxE (impact = range x abundance x per capita effect).

What is propagule pressure?

The quantity, quality, and frequency of arriving organisms that influence the success of an invasion.

What affects the success of an invasion in terms of the invaded community?

Climate and habitat must be hospitable; local richness and interactions must accommodate the new species.

What role does disturbance play in species invasions?

Disturbance can make communities more susceptible to invasion by making resources available.

What approach is central to invasion prevention?

Identifying and regulating pathways for species introduction.

Which U.S. legislation aimed at controlling invasive species was enacted in 1990?

The National Aquatic Nuisance Prevention and Control Act.

What year was the National Invasive Species Act established?

1996.

What is a key principle of controlling species invasions?

The precautionary principle: guilty until proven innocent.

What is the primary objective of careful management in invasive species control?

To prevent invasions by identifying pathways and implementing regulations.

What role do government agencies play in managing invasive species?

They may mandate introductions of species for ecological or economic purposes.

What does the successful invasion of a species imply?

That it has overcome a series of ecological filters or barriers.

What is the relationship between invasive species and local biodiversity?

Invasive species can disrupt local ecosystems and negatively impact native biodiversity.

Why might a biological control approach lead to unintended consequences?

Nontarget species may be the most affected by the introduced control agents.