Invasive species

1
Invasive species
2
(No Transcript)
3
(No Transcript)
4
Examples of invasive plant species

• Miconia (Miconia calvescens)
• Purple loosestrife (Lythrum salicaria)
• Strawberry guava (Psidium cattleianum)
• Water hyacinth (Eichhornia crassipes)

http//www.pbs.org/wgbh/nova/algae/matc-nf.html
5
Miconia (Miconia calvescens)

• This plant from Central and South America was
  brought to Tahiti in 1937 and planted in a
  botanical garden. Fruit-eating birds have spread
  its seed, and now miconia covers more than half
  the island. It has become the dominant canopy
  tree in Tahiti, shading out many native plants.
  Unlike the island's indigenous trees, it has a
  shallow root system, which has led to landslides
  where the trees have grown on hillsides. It
  thrives in the tropical climate and spreads
  quickly. In its native habitat of Central and
  South America, fungi and insects control its
  spread.

6
Purple loosestrife (Lythrum salicaria)

• This plant from Europe and Asia came to North
  America in the early 1800s on the wool of
  European sheep and within ships that used soil as
  ballast. It was also brought as an ornamental
  plant and as a source of nectar for bees kept by
  beekeepers. By the 1830s the plant was common
  along the east coast of the U.S. Purple
  loosestrife is now found throughout most of the
  U.S. and Canada. It spreads rapidly and invades
  wetlands by displacing native plants, creating an
  environment that provides little food or shelter
  for native wildlife.

7
Strawberry guava (Psidium cattleianum)

• The strawberry guava, which is native to the
  Atlantic coast of Brazil, has now spread to
  Polynesia, Mauritius (an island in the Indian
  Ocean), Hawaii, Puerto Rico, and other tropical
  locations around the world.
• In Hawaii, the feral pig, another invasive
  species, assists in the spread of strawberry
  guava by eating its fruit and dispersing its
  seed. The plant was brought to Hawaii (and
  elsewhere) for its edible fruit but soon after
  its introduction escaped from gardens. A shrub or
  small tree that can reach 15 feet in height, the
  plant not only shades out underlying native
  vegetation, it also sends out feeder roots that
  inhibit native plants' growth. In Hawaii,
  strawberry guava is considered an especially
  invasive plant pest

8
Water hyacinth (Eichhornia crassipes)

• Native to South America, water hyacinth is one of
  the worst invasive species known. It spreads at
  extremely fast rates, in favorable conditions
  doubling its numbers in as little as 12 days. The
  plant, which floats on the water's surface, can
  cover large areas, thus limiting boat traffic,
  swimming, and fishing. By blanketing the surface,
  the plant also prevents sunlight from entering
  the water. Moreover, when it dies, the decaying
  plant matter robs the water of oxygen. The
  reduced amount of sunlight and oxygen in the
  water disrupts plant and animal life, adversely
  affecting the habitat's biodiversity.