1. Introduced Species

2. Biological invasion:
occurs when a species arrives in an area in which it was previously not found

3. Exotic Species
an organism that has invaded an ecosystem in which it did not evolve
throughout the course of history, human beings have introduced many species to new ecosystems
in some regions a large number of the species present are not indigenous
Examples:
New Zealand: 47% of species have been introduced
Canada: 28% of species have been introduced
Hawaii: % of species have been introduced

4. not all species that were introduced survived
if 100 new species are placed in a new ecosystem:
87 will die off
10 will successfully colonize
2-3 will become pests

5. species can be introduced:
1. Intentionally: Agriculture Biotechnology
Pet trade
Ornamental
2. Accidentally: Ship ballast
Air travel
Escape from agriculture
introduced species have a HUGE impact on the balance of an ecosystem

6. Epic fail – the cane toad

7. Ecological Impacts Direct predation Plant pathogens
Disease transmission
Disruption of food web
Loss of biodiversity
Extinction

8. Economic Impacts Russian wheat aphid $130 million/year
Mediterranean fruit fly $897 million/year
Zebra mussel $5 billion/year
Boll weevil $50 billion (since 1890's)
The Russian wheat aphid (Diuraphis noxia) is an aphid that can cause significant losses in cereal crops.
the Mediterranean fruit fly, or medfly for short, is a species of fruit fly capable of causing extensive damage to a wide range of fruit crops.
The native distribution of the species is in the Black Sea and Caspian Sea in Eurasia. Zebra mussels have become an invasive species in North America, Great Britain, Ireland, Italy, Spain, and Sweden. They disrupt the ecosystems by monotypic colonization, and damage harbors and waterways, ships and boats, and water treatment and power plants. Water treatment plants are most impacted because the water intakes bring the microscopic free-swimming larvae directly into the facilities. The Zebra Mussels also cling on to pipes under the water and clog them.
The insect crossed the Rio Grande near Brownsville, Texas to enter the United States from Mexico in 1892[1] and reached southeastern Alabama in By the mid 1920s it had entered all cotton growing regions in the U.S., travelling 40 to 160 miles per year. It remains the most destructive cotton pest in North America. Mississippi State University has estimated that since the boll weevil entered the United States it has cost U.S. cotton producers about $13 billion, and in recent times about $300 million per year.

9. introduction of species to new environments can be prevented in a number of ways
1. Inspections at travel centres
2. Ballast regulations
3. Control of “established exotics”
shooting & trapping
mechanical removal (plants)
Pesticides
biological control

10. Organic Farming
organic farming involves using agricultural practices that are environmentally friendly
source of nitrates is manure and legumes with nitrogen-fixing bacteria within the roots
crops grown are very diverse and mature at different times of the year
this ensures that different nutrients are released from the different plants on a continual basis
relies on nature to control pests and weeds

11. crop diversity reduces the need for pesticides
due to susceptibility of crops to pests, smaller yields are produced resulting in higher prices
many health benefits are realized