Lecture 9: Invasive Species Flashcards
Invasive Species
a species that arrives (often with human assistance) in a habitat it had not previously occupied, then established a population and spreads autonomously.
Tend to be adaptable, fast reproducing, and are particularly common on islands.
Case Study: The Brown Tree Snake in Guam
- Brown Tree Snake was accidentally introduced on aircraft
- Rapid spread across the island
- Decimated Native Birds : excessive predation
Ecological Impacts of Invasive Species
- Ecosystem Modification
- Resource Competition
- Predation
- Herbivory
- Parasitism
- Invasional Meltdown
Ecosystem Modification
invasive species can modify entire ecosystems through:
- physical habitat changes
- overgrowth and shading
- changing the fire, water, nutrient regimes
- selective parasitism of a dominant species
Case Study: Japanese Stiltgrass in Tennessee
- Introduced to Tennessee as packing material in porcelain shipment from China
- Grows well in many light-conditions, especially in disturbed areas, and is resistant to herbivores
- Control through mechanical, biological, chemical
Resource Competition
when the invasive species uses resources more efficiently than the native competitor
Predation
predators are often released for “biological control” and some become highly invasive.
Herbivory
- Invasive goats decimate native vegetation, reducing food for Galapagos Turtles
- European rabbits have devastated native plants on island worldwide, causing erosion.
Case Study: Sea Lamprey Parasitism in the Great Lakes
-native to Atlantic Ocean
-resemble eels, but unrelated
attach to fish with their suction cup mouth, dig their teeth into flesh for grip, and rasp through the fish’s scales with sharp tongue.
-control: lampricides, pheromones and alarm cues, barriers and traps
Invasional Meltdown
when two or more introduced species interact, increasing the survival and/or ecological impact of atleast one of them.
