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Chronology of an Invasion
In 1980, a cold-resistant strain of Caulerpa Taxifolia was distributed to several
aquariums, including the Oceanographic Museum at Monaco. 4 years later, a small patch
of this alga was observed underneath the Monaco museum. At the time, it was not
considered alarming enough to have pulled it out by hand. By 1989, 2 ½ acres had grown
under the museum. Alexandre Meinesz embarks on a mission to contain the threat. Over
the next several years, he and other scientists attempt to engage first the French, and then
other Mediterranean countries. Unfortunately, much of the scientific discussion devolves
into bickering about the source of the infestation, particularly the involvement, or lack
thereof, of the Mediterranean government.
By 1998, concern about the alga reached the UN. In 1999, the French launched an
investigation into the government’s slow response to the threat. The US officially listed
c. taxifolia as a noxious weed.
By 1992, over 1000 acres are infested, near Monaco, France, Italy, and Spain. It
spreads to Croatia in 1994, and has reached California by 2000. In 2001, the alga was
discovered near Sydney Australia. As of 2003, the spread of the alga continues despite
world efforts to contain it.
Impact of Invasive Species
The impact of an invasive species depends on factors such as the extent to which the
species invades the territory. The author identifies 4 levels of damage. At level 1, species
simply enter a small range of spaces without overly the native inhabitants. At level 2, ,
they become more dangerous by competing with or threatening a few native species, as
the gray squirrel did to the native red squirrel in Great Britain.
At Level 3, the introduced species can threaten an entire ecosystem, like the comb
jellyfish, which has singlehandedly decimated the fish population in the Black Sea since
its introduction in 1982. This jellyfish was transported into the Black Sea, and promptly
ate all the plankton and fish larvae, destroying the catches of anchovies, sprat, and horse
mackerel. The numbers have dropped in recent years but there are still occasional
blooms.
Level 4, introduced species affect more ecosystems. These are usually species that
are less specialized and can live in many different places. One example is the water
hyacinth, which was deliberately imported from the Amazon as an ornamental plant. In
Louisiana and Florida, the plant interfered with navigation and choked out life in rivers
and lakes. The plant has now colonized Lake Victoria in Africa and parts of Asia. Its
impacts include interference with machinery, and its effects on native species are still
unknown.
C. Taxifolia is another example of a Level 4 invader. Other examples are Kudzu
and Spartina Alterniflora in the US.
Matching aliens with impact
Has toxic skin … cane toad
Kills crabs … crazy ant
Crop killer … feral pig
Taking over Tahiti … Miconia
European invader … Purple loosestrife
Eats rats and more …. Small Indian mongoose
Little bully … Mosquito fish
Thicket expansion … strawberry guava
Likes its plankton …. Zebra mussel
Super fast spreader …. Water hyacinth
Saving the Magpie Robin
The magpie robin was down to a population of less than 20 birds on a single island in the
Seychelles. The population has since been increased to 90 birds on 3 islands.
The magpie robin is native to canopy forest in the Seychelles and only has 2
natural predators, a skink and a snake. However, when Europeans arrived in 1770, they
began cutting the forest and habitat was lost. Bird collectors killed them, as did
introduced predators.
In the 1970s, conservationists attempted to start new colonies, but the attempts
failed. BirdLife International started a project to observe the robins in their native habitats
and find out the causes of their near extinction. Factors found were loss of habitat, lack of
nesting sites, predation by mynah birds, and pesticides.
The conservationists responded by building nests, feeling the birds, planting trees,
getting rid of the mynah birds, and banning pesticides. Once the population of birds had
doubled, they established a new colony of birds on Cousin, a small island nearby. In
1987, after colonies had been established on Cousine, the bird was removed from the
endangered species list. The next goal is to establish a colony on Aride, but so far that
effort has been unsuccessful.
Continued activities include international partnerships, improving release and
feeding methods, and the development of aviaries. The magpie robin is on the road to
recovery but still faces many threats, including the possibility of decreased awareness and
reintroduction of predators.
Why do Islands Breed Giants?
Animals colonizing new islands tend to become either giants or dwarfed.
Giant animals include Komodo dragons, Madagascar hissing cockroaches, and the
New Zealand moa (extinct). Dwarf animals include foxes, rabbits, snakes, and even a
mammoth.
In 1964 Bristol Foster categorized animals by their sizes on islands compared
with mainland counterparts. He found that big animals tended to shrink, and small
animals tended to get bigger. He suggested it might be because of fewer predators and
competitors. Smaller animals might survive better if there were scarce resources.
In 1967 MacArthur & Wilson published the Theory of Island Biogeography,
which encouraged scientists to study how plants and animals evolve on islands.
In 1978, Ted Case expanded on Foster’s work, pointing out some serious
omissions and inconsistencies. He noticed that the same animal sometimes dwarfed on
one island and became giant on another. Case decided that the main factor was the
amount of energy an animal could take in, in a set period of time. Other factors were the
available niches, and the tendency of increased size to interfere with other abilities, such
as flying.
Large creatures can have more offspring and use a wider range of resources.
Smaller creatures don’t need as many resources, and can hide better.
Changes in size can occur very rapidly, on the scale of a few thousand years.
Humans can also affect the change in size, as they tend to hunt larger animals from larger
species, causing dwarfing of the remaining animals.
Kanzai the Bonobo
Sue Savage-Rumbaugh
Kanzai is different from other language learning apes. He was raised by his mother
because he was part of an endangered species. All other ape language students were taken
from their mothers. He had no training. No rewards, etc. Researchers talked and used
symbols around him, and he learned. He learned graphic symbols instead of hand signs.
They are written so they can be used on a screen, or used with a camera. There is a record
of what the ape has done, as opposed to with hand signs. They’re geometric symbols.
There are about 360 symbols on the board, and he knows them all. It’s harder to know
how many words he knows. He knows words like “it”, and can respond appropriately if
you say “Can you get it?” He can play games like keep-away and video games. He
learned to play Ms Pacman by following English instructions. Kanzai and his researchers
have become very close and are respectful of each other. The researchers are confident
that Kanzai is using language and want to know how it helps apes organize into cultural
groups.
Read my Lips
The apes have facial expressions and body language for interacting with other bonobos.
They play airplane with young apes. They hold hands to show friendship. They wrestle
while making a play face to show that they are playing, not fighting. Adults also play
with each other, not just with children. Adults can ask for food by pursing their lips. They
show fear by grinning with teeth bared. They also kiss as a sign of affection or as a
greeting.
Jewel of the Underground
Lechuguilla in New Mexico’s Guadalupe Mountains is one of the deepest and largest
caves in America. It is closed to the public permanently. One room is Glacier Bay, which
has huge blocks of gypsum and water dripping down a shaft. Lake Chandalar is getting
covered over with shelfstone. Hoodoo Hall is a room of raft cones with aragonite bushes.
The Chandelier Ballroom has stalactites up to 20 feet long. Underground Atlanta contains
huge stalagmites and a 278 foot drop down to a pit called the Chicken Little Room. Lake
Louise has ‘mammallaries” hanging form the ceiling. The Chandelier Graveyard has a lot
of gypsum stalagmites that look like tombstones. The Oasis has calcite formations and
the remains of a lake. Nirvana has a floor of red flowstone and white dripstone on the
ceiling. Coralloids are called cave popcorn, and are formed by evaporation.
How Caves Form
Rainwater: Limestone caves are made when the rain seeps into the soil. The water joins
with C02 to form carbonic acid. The carbonic acid gets into the water table and eats away
the limestone right below the water table. It dissolves the limestone in channels. The cave
stops enlarging when the water table drops.
Waves: Waves can make sea caves. An overhang can form because the waves beat at the
base of the cliff. They are typically found in soft rock like limestone.
Lava: Lava waves are formed within a lava flow. Slow moving lava on the outside
hardens while fast moving lava in the flow continues to flow like liquid through a straw.
When the lava stops, the tube empties. The end of the tube is blocked with hardened lava,
and only becomes visible if part of the cave collapses.
Bacteria: Extremophiles (heat-loving bacteria) put off Hydrogen sulfide, which travels up
into the cave through the groundwater. It forms sulfuric acid which dissolves the
limestone. Other bacteria can eat sulfur, manganese, and other minerals. Lechiguilla Cave
is thought to have been formed this way.