Chinese Giant Salamanders
(Andrias davidianus)
How does the
pace of change
compare to the
speed at which
the species is
able to evolve?
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Ancestors of the Cryptobranchidae diverged from all other
amphibians over 170 million years, ago during the Jurassic
Period.
This proves that the CGS had little evolution over the years if
at all.
So combined with the sudden increase of human poaching,
pollution, and habitat loss, which happened in span of a few
decades. It is safe to say that the pace of change is too fast for
the CGS to evolve and combat.
What influence is
the human action
having on the
genetic diversity
of the threatened
species? Is there a
risk of causing
genetic
bottleneck?
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In previous years the Chinese Giant Salamander was thought
to be one species, now recent studies show it could actually be
up to 8 individual species.
As a result of CGS farms continuing to abide by old
information, when told to release some of the salamanders,
they do not take into consideration if the salamanders they
were releasing were of different species
This results in unwanted hybridization because then the
offspring are not able to reproduce either, which hinder
population growth and damage genetic diversity.
The risk of genetic bottleneck comes from the fact that the
farm salamanders are different to those living in the wild, and
bring with them traits that the wild ones do not have when
the breed, such as a average smaller size.
What influence is
the human action
having on the
genetic diversity
of the threatened
species? Is there a
risk of causing
genetic
bottleneck?
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Released salamanders and other endangered animals that are
kept at the farm are not screened for disease or for their
genetic provenance.
This is how “genetic pollution” results in that weaker genes
that were spread throughout the farm, will also weaken the
offspring of the wild salamander offspring as well.
The internal CGS trade amongst farms across large parts of
China, including across the watersheds, also drive these
disease and genetic threats to wild CGS.
Farms sometimes release these Salamanders in a group with
other family members into areas with no salamander
population, which leads to these animals inbreeding with each
other.
Farms are also known to take salamanders from the wild,
reducing the amount of possible different genes in the gene
pool of mates.
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By the year 2000, 90% of the Chinese giant salamanders' habitats are destroyed
or uninhabited.
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How do new
conditions
compare to the
conditions under
which threatened
species evolved?
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It is paramount that the CGS reside in more oxygenated waters because of their
complex method of receiving oxygen.
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The loss of habitable land can be attributed to multiple sources such as Siltation, the building
of dams, the expiration of land, and most problematic, the water pollution. These conditions
differ greatly from past when CGS habitats were much safer.
As a result of the CGS receiving oxygen through its skin it is also more susceptible to the toxic
chemicals in the water as well. Such chemicals didn’t exist in the past and in relation CGS
populations were healthier.
It is also bad that CGS has lost so much habitable land because it requires fast flowing and cool
water to intake the oxygen best, so when it’s forced to migrate to still water, neither situations
are ideal for its survival. In contrast to the past, land wasn’t destroyed for anthropogenic uses
thus fragmentation didn’t exist.
It is also suboptimal that the waters are so polluted because of the delicate
fertilization process.
○ As a result of CGS eggs having no protective outer layer, it is very easy
chemicals in the water such pesticides and herbicides to infiltrate the
egg.
○ This has caused an ample increase of unfertilized eggs compared to when
there wasn’t any chemicals in the waters and eggs could develop
normally.
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How do new
conditions
compare to the
conditions under
which threatened
species evolved?
CGS are ectothermic, so temperature variability is a concern
when choosing a habitat
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Algal blooms can prevent oxygen from reaching CGS
As a result of fertilization runoff algal blooms can form which extracts a
lot of the oxygen from the water around it, which also make it hard for
the CGS to survive. These weren’t as common in the past
As a result of increasing anthropogenic land-use changes, the range of the CGS is
currently thought to be fragmented into 12 separate areas, With the distance
between these areas, natural migration would be impossible.
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Pollution can also affect the temperature because a decrease in dissolved
oxygen, in turn causes thermal pollution that can increase temp. since
warm water holds less oxygen than cold water does. Again, chemical
pollution didn’t exist in the past so more CGS would survive because the
temp. range was cooler.
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Consider ways of
halting or
reversing the
human actions
that are
responsible for
threatening
species.
Strengthen current laws surrounding the protection of
the CGS.
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The fine for poaching is extremely low ($6USD), with a more than
attractive reward ($250-$400 USD/kg). If the fine were to be increased
poaching would be decreased.
Most of the poaching of CGS is within the “protected” areas specifically
for these animals.
Have the government buy the salamanders back from the
farms.
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If the government were to buy back the salamanders
facilities would be built where the salamanders could safely
develop.
Salamanders could also be properly released back into the
wild.
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The proper release of Salamanders
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Consider
alternatives that
do not reduce the
ability for the
species to evolve.
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The kidnapping of wild Salamanders
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Upon release of a salamander, the identification of its native habitat is
crucial.
With this information, the hybridisation and the homogenisation of
the CGS gene pool of one species with another that is supposed to be
living in a different habitat is eliminated, thus reducing the risk of
genetic bottleneck and the unnatural genetic variation.
If possible, it would be massively beneficial if farms that were found to
have obtained many salamanders from kidnapping them from the wild
were to be shut down.
The investigation of CGS farms to see if they’re not taking too many or
unethically taking salamanders from the wild would be of great help.
Putting a weight limit on farmable salamanders
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Studies show that mature salamandres have an increased chance of
survival compared to infant salamanders
Thus reducing the amount of farmed (mature) salamander might slow
down endangerment rates because they are more resilient.
This might be difficult because mature salamander weigh and have
more meat than younger salamanders so a compromise will be the best
course of action. (weight/size limit).
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Identify actions
that might
enhance the
ability of the
threatened
species to adapt
to new
environmental
conditions.
The protection of and prevention of destruction of habitats is the
most important task in saving the Chinese Giant Salamander
○ It is a necessity not only for the CGS, but also for
most organisms that all types of industry find a
different way to get rid of waste, instead of dumping
it in water.
○ This includes everything from agriculture to
factories.
○ Destruction of habitats in many different forms also
needs to be stopped.
○ This includes everything from deforestation to
poachers using terrible tactics such as dynamiting.
● The ban or limited use of chemicals such as pesticides
○ The control or ban of pesticides would be a hugely
beneficial thing to the CGS. Many chemicals used
commonly are very harmful to CGS, even their eggs.
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Make a
Decision
Law
The increase the severity of the law would be most
beneficial for the CGS
○ The main problem with the law enforcement
surrounding the CGS is there is not a large enough
penalty for hunting and killing these animals.
○ If the fine for poaching salamanders as equal to how
much the salamanders were actually worth, their
population rates would surely rise.
○ In addition if people were to serve time for
poaching, the risk to reward ratio would make
hunting for the salamanders futile.
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Make a
Decision
Farms
The reduction of accidental hybridization of different
species is a must.
○ The salamanders from farms must be properly
identified and brought to the right habitat as to
not mix the different species of CGS upon
release into the wild.
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Make a
Decision
Prevention of
Habitat
Loss/Pollution
The main type of destruction and pollution of nature
which most affects the CGS is water.
○ Agricultural sites and industrial buildings must be
stopped from simply releasing waste or getting
chemicals into water sources. The effect which they
have upon not just the CGS, but on all organisms is
massive. If water is too polluted, it makes areas
where the CGS lives inhabitable and makes
habitable areas near fatal for them.
○ These chemicals and waste are extremely harmful
towards the CGS and its eggs.
Polluted Habitat/Reserves of
the CGS
Chinese Giant Salamander eggs
Poorly kept CGS farm that
allows for disease to spread
Map that shows
Extensive
Fragmentation of
CGS population.
Walmart in China
Selling live CGS
And contributing to
Its endangerment
Multiple alarming problem
with the CGS reserves
Chart showing length and
weight of CGS in relation
To age
Shows a a big different in size of captive CGS to the ones released
in the wild. Smaller CGS have a lower chance of surviving in the
wild compared to those that are fully grown.
Citations
Snell, J. (2014, December 4). Temperature effects on the Chinese giant salamander. Phys.org. Retrieved May 6, 2022,
from https://phys.org/news/2014-12-temperature-effects-chinese-giant-salamander.html
Wikimedia Foundation. (2022, May 6). Chinese giant salamander. Wikipedia. Retrieved May 6, 2022, from
https://en.wikipedia.org/wiki/Chinese_giant_salamander
Chinese giant salamander: Millions farmed, nearly extinct in the wild. Mongabay Environmental News. (2015,
November 23). Retrieved May 6, 2022, from
https://news.mongabay.com/2015/11/chinese-giant-salamander-millions-farmed-nearly-extinct-in-the-wild/
Chinese giant salamander conservation. Zoological Society of London (ZSL). (n.d.). Retrieved May 6, 2022, from
https://www.zsl.org/conservation/regions/asia/chinese-giant-salamander-conservation
Chinese giant salamander (Andrias Davidianus) - extinction.photo by Marc Schlossman. Extinction. (n.d.).
Retrieved May 6, 2022, from https://www.extinction.photo/species/chinese-giant-salamander/