Quiz 2 Flashcards
Q: Where do most non-native species come from?
A: Europe provides the most non-native species to the world, especially to North America. There are 10 times more species movements from Europe to North America than vice versa (Pyšek et al. 2003).
Q: What are the hypotheses explaining asymmetry in non-native species movements at inter-continental scales?
A:
Purely anthropogenic reasons: Variable number of introduction attempts.
Ecological/anthropogenic reasons:
Diverse communities are more resistant to invasion.
Differences in recent and past habitat disturbances.
Early human disturbances in Europe led to communities adapted to disturbance.
Asymmetry in sampling bias.
Q: What is the “Ecological Imperialism” hypothesis?
A: European immigrants brought native species to new lands, causing an asymmetry in non-native introductions, especially to North America.
Q: What does “invasibility” mean in ecological terms?
A: Invasibility refers to a geographic region’s susceptibility to higher rates of invasion. Regions with high invasibility are more prone to being invaded by non-native species.
Q: How does recent disturbance influence species invasions?
A: Disturbance can promote biological invasion, but it likely doesn’t explain continent-level asymmetries in invasions. Violent storms are localized, whereas human-caused disturbances occur globally and are more consistent.
Q: What is meant by “human-altered habitats” in Europe, and how does this relate to non-native species?
A: Native species in Europe are adapted to long-standing human-altered habitats. This pre-adaptation may make them better suited to invade newly disturbed habitats, such as those in North America.
Q: What factors contribute to the accelerating rate of non-native species introductions since 1960?
A:
Increased trade.
New pathways for species movement.
Increased awareness and more scientific sampling.
Q: What are the major vectors for non-native species introductions?
birds, marine, plants
Birds & Mammals: Pet trade (since 1700).
Marine: Attachment (1700s) and ballast water (2000s).
Terrestrial plants: Silviculture (1700s) and ornamentals (2000s).
Q: Why might there be an asymptote in non-native species introductions in some areas? two hypotheses
Hypothesis 1: Fewer non-native species arriving in ports, possibly due to reduced trade or increased inspections.
Hypothesis 2: Saturation of the non-native species pool, where fewer new invaders are likely to arrive over time as species have already established.
Q: What are species accumulation curves and how are they used?
A: Species accumulation curves are used to estimate biodiversity and control for different sample sizes or areas. They help in understanding species richness and the saturation point in non-native species accumulation.
Q: What is “invasion debt”?
A: Invasion debt refers to the current non-native species richness explained by historical socioeconomic factors. Non-native species richness in an area may be a result of past human activities.
Q: Where do invasions occur latitudinally?
A: Invasions tend to be low at high latitudes and in the tropics. The peak invasibility occurs in sub-tropical regions.
Q: What is the ecological concept behind low invasion rates at high latitudes?
A: High latitudes have low energy, which limits species adaptation and results in a small species pool. Only species adapted to cold can survive, reducing potential invaders.
Q: What are the ecological concepts behind low invasion rates in the tropics?
Carrying capacity: High diversity in the tropics results in a low availability of resources for invaders.
Competition: Tropical regions have high competition among native species, creating barriers for non-native species.
Ecological disturbance: Tropical regions tend to have low disturbance, which also reduces invasibility.
Q: What is the alternative explanation for low invasion rates in the tropics?
A: Less developed tropical countries may have lower trade and, therefore, fewer non-native species arriving compared to developed regions.
Q: What are the two hypotheses for why the rate of non-native species invasion may decline over time?
A:
Decrease in trade, which reduces the arrival of new species.
Saturation of the species pool, where fewer new non-natives are likely to arrive as those with high potential to invade have already established.
Q: What latitudinal zone experiences the highest invasibility?
A: The sub-tropical and lower temperate regions experience the highest invasibility.
Q: What are the three hypotheses for the asymmetries in non-native species movements?
A:
Purely anthropogenic: Variable introduction attempts.
Ecological/anthropogenic reasons:
Diverse communities resist invasion. Differences in habitat disturbances.
Differences in past human disturbances.
Asymmetry in sampling bias: More scientifically invested regions have inflated records of non-native species due to better sampling efforts.
Q: How can historical events influence non-native species accumulation?
A: Historical events such as the removal of the Berlin Wall, the opening of trade with China, or other wars can change trade routes and patterns, altering the rate of species accumulation.
Q: What is a propagule?
A: A propagule is biological material (e.g., seeds) used to propagate an organism into the next generation through dispersal.
