· The Desert Tortoise (Gopherus agassizii)
State the scientific name and common name of your
organism, its taxonomic Order, and taxonomic Family.
Kingdom: Animalia. Phylum: Chordata. Class: Reptilia. Order:
Testudines. Family: Testudinidae. Scientific Name: Gopherus agassizii. Common name: Desert Tortoise.
Include two photos or one video (no more than
two minutes in length) illustrating the organism in its natural setting. Do not
use any material showing harm to this organism.
Explain this organism’s ecosystem role. Since the desert
tortoise is a primary consumer, their pray consists of various mammals, avian
(birds), and reptile predators. Desert tortoises are also called ecosystem engineers because they make
us of other animals’ hard work like digging burrows that are used as shelters
by snakes (Serpentes), lizards (Sauria), birds (Aves),
rodents (Rodentia),
javelinas (Pecari
tajacu), and insects (Insecta) and
other invertebrates. Desert tortoises themselves take advantage of packrat (Neotoma
albigula) houses for shelter. In one study, desert tortoises were found
sheltering with large colonies of Africanized honeybees (Apis
mellifera)--a very effective defense against predators! Finally, desert
tortoises have few external parasites, but they are host to intestinal pinworms
(Oxyurida).(Crozier).
Describe at least two ecological
services this organism provides for humans and other species (at least two
ecological services for each, humans and other species). This might involve its
food web.
In the
past, desert tortoises were used by indigenous peoples of the American
Southwest for food and medicine, and the shells were used to make bowls,
ladles, and shovels. Desert tortoises were also central figures in the folklore
of the region. Desert tortoises are occasionally still used for food in some
parts of Mexico. In addition, many people in Arizona keep desert tortoises as
pets, though the keeping of captive tortoises is strictly regulated: tortoises
must not be collected from the wild, only one tortoise is allowed per family
member.(Crozier).
Include and explain in words, a chart or
graph showing population of this organism over time.
State how the equation I = PAT is involved in
the threats to this organism.
I = PAT stands for (I) Environmental impact =
population (P), affluence (A) and technology (T) to environmental impact (Santa Barbara Foundation Family). As our population grows this animal becomes
more prone to threat. Since our actions as one affects our environment, it also
impacts every organism on the planet in some way shape or form. As population increases we build more, which
in return results in more roads etc. This is where affluence comes in because
we can’t seem to stop building and humans want more and more. We feel as though
we must make more roads to get places and to build in places that are
necessary. Which bring us into technology, we need the technology to build and
develop these new places. For example, in 1995, populations in areas of the
Mojave and Colorado deserts with comparatively little human activity were
generally stable or declining more slowly than populations in areas with high
levels of human activity (Santa Barbara Foundation Family).
Referring to figure 9-3 in your text book,
determine and describe the characteristic(s) that endanger(s) your species.
The Desert Tortoise extinction falls under every part of
HIPPCO. Habitat
degradation from overgrazing, vehicle use, and invasion by nonnative grasses
may have substantial negative impacts on desert tortoises. The impacts of
severe grazing on their habitat suggest that high levels of grazing likely have
negative impacts on desert tortoises. Potential effects of intense grazing that
could negatively impact desert tortoises include soil compaction, decreased
cover of annual plants, introduction of nonnative species, competition for
forage, and the potential for trampling desert tortoises and their burrows.
Invasion of nonnative grasses and the potential for a nonnative grass/fire
cycle pose major threats to desert tortoises. The release of captive desert
tortoises with upper respiratory disease syndrome, which is typically fatal,
into the wild may have resulted in the infection of wild desert tortoises (Santa Barbara
Foundation Family).
Although a new species is not being introduced, I feel it is an example that
could fall into introducing a new species that result in destruction to the
species. Climate change may negatively affect the desert tortoise if droughts
become more frequent or severe or if precipitation increases and results in the
spread of nonnative plant species (Santa Barbara Foundation Family).
Determine if this organism is affected by
density dependent and/or density independent factors. Explain the situation in
some detail.
The Desert Tortoise would be
considered to be affected by density independent because of the main threat of
humans including, but not limited to fire mostly human caused.
Describe the feedback loops involved.
A positive feedback group is involved with the Desert
Tortoise especially because of the invasive plant life. This plant life is
burned it causes a decrease in habitat for the tortoise. Since most of their
food comes from plant life this causes a worse and worse situation for the
essential habitat of the tortoise.
Describe how global climate change is
affecting or is predicted to affect this organism’s habitat.
Climate, like
stated above is having a negative effect on this species because of the plant
life. The habitat is in need of native plant species and thus a drought
inclines their habitat to inhabit nonnative plant species more frequently.
Referring to the three principles of
sustainability, why should humans care about this organism?
This species is
considered ‘keystone’ to the Mojave – meaning that it plays a significant role
in maintaining the integrity of the desert ecosystem and, if lost, will put
other species at risk for extinction. (Collaborating for a sustainable future for wildlife). Maintaining our
impact on this species by educating the public of this threatened species will
in return help us a unit to make changes to help our ecosystem survive. The
Desert Tortoise spends about 95% of its time underground in the burrows they
make, which act as a protector for other species as well. This acts as a very
important role for many species living in the desert (Leon).
Name and give a two or three-sentence
description of two individuals (not groups) who are champions of this organism.
Roy Averill-Murray, Gopherus agassizii expert, is a part of
the U.S. Department of Fish and Wildlife Service, of which is working to
protect the Gorpherus agassizii (Richards-Dimitrie).
Roy is the Desert Tortoise Recovery Coordinator that is from the Nevada office
and has been with the U.S. Fish and Wildlife Service since 2004 (Averill-Murray). Christopher R. Tracy is an expert on
the desert tortoise (gopherus agassizii), having written an entire
manuscript, “Desert Tortoise Recovery Plan Assessment”. He
is an assistant professor at California State University, Fullerton,
having gotten his masters at the University of Oklahoma, and his PhD at
the University of Wisconsin, Madison. His research includes
Physiological Ecology of Reptiles and Amphibians, Physiology
of Terrestrial Vertebrates, Ecology of Desert Vertebrates (Christopher R. Tracy).
Name and give a two or three-sentence
description of two individuals (not groups) who do not want this organism
protected, at least not in their “own backyard.”
Cliven
Bundy, who is against preserving the Desert Tortoise. Clive stated that he
“will not willingly sell their grazing privileges to create another preserve”(Fuller).
Unfortunately, after strenuous research, I was unable to find another specific
name associated with another individual against the protection of the Desert
Tortoise. Although, there are many ranchers who are also opposed to the idea
none were publicized by name. However, it was fought that the government is
acting hypocritical in that they will be euthanizing these animals’ dues to
budget cuts.
Include a link to one recent scientific
article or story about this organism that was written or produced in the last
year. Suggestions for sources include ScienceNews, ScienceDaily,
and NPR. Your article or story must include some peer-reviewed material
or state the view of scientific experts. Introduce the links in your report by
giving a one or two-sentence summary of each.
An article written in April earlier this year, talks about how the
Desert Tortoise will soon be euthanized due to federal funds. The Desert
Tortoise Conservation Center near Las Vegas has been in operation for decades
and now the funds to run the conservation are dwindling. There has been many
laws put into effect to help these critters to stay safe from human
destruction. As a result any new tortoises brought to the center will now be
euthanized as there are no other options (Animalsoul). <http://ireport.cnn.com/docs/DOC-1119214>
State the Precautionary Principle in your own
words.
The precautionary principal
involves taking precautionary measure to prevent species from being extinct. We
can become more aware that our actions are affecting extinction of every
species even if we are lacking scientific knowledge of this happening for some
species.
Works Cited
“Collaborating for a sustainable future for wildlife.” C2S2 Conservation Centers for Species
Surival. Web. 2014 July 18
<http://conservationcenters.org/species-conservation-priorties/desert-tortoise/>.
“Christopher R. Tracy.”
California State University, Fullerton: Biological Sciences. April 7, 2014. Web July 19, 2014. <http://www.fullerton.edu/biology/People/facultypages/tracycr.asp>
Crozier,
G. 1999. "Gopherus agassizii" (On-line), Animal Diversity Web. July
19, 2014 <http://animaldiversity.ummz.umich.edu/accounts/Gopherus_agassizii/>.
“Desert
tortoise (Gopherus agassizzi).” U.S.
Fish & Wildlife Service Species Profile.” 18 July 2014. Web. 18 July 2014.
<http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=C04L>.
“Gopherus
agassizii.” The IUCN Red List of
Threatened Species. Web. 16 July 2014.
<http://www.iucnredlist.org/details/9400/0>.
Mayer, Rachelle. Gopherus agassizii. 2008. 18 July
2014 <http://www.fs.fed.us/database/feis/animals/reptile/goag/all.html>.
“Mojave
Population of the Desert Tortoise (Gorpherus agassizzi).5-Year Review: Summary
and Evalutation.” U.S. Fish and Wildlife
Service Desert Tortoise Recovery Office Reno, Nevada.” 30 September 2010.
Web. 18 July 2014. Pg18 <http://ecos.fws.gov/docs/five_year_review/doc3572.DT%205Year%20Review_FINAL.pdf>.
“The Sustainable Scale Project.” Santa Barbara Foundation Family.
2003. 18 July 18
<http://www.sustainablescale.org/ConceptualFramework/UnderstandingScale/MeasuringScale/TheIPATEquation.aspx>.
Tuma, Michael. “Agassiz’s Desert Tortoise Gopherus agassizii.” Reptiles of Arizona. 2008. Photograph.
Web. 15 July 2014. <http://www.reptilesofaz.org/Turtle-Amphibs-Subpages/h-g-agassizii.html>.
Wildertography. Desert Toroise (Gopherus
agassizii) Attacks! 15 April 2012. <https://www.youtube.com/watch?v=Z4hDadw7HVc>.
