Digging Around for the Facts

The eggs in the live-feed photo at right were laid by a captive raised Desert Tortoise female the Victor Valley located in the Western Mojave Desert. This clutch of Desert Tortoise eggs are being incubated in the LCER/AAE biology classroom using a water bath warmed with an aquarium heater. The water/air temperature fluctuated between 30 and 32.5 degrees C ( 86 to 92 degrees F). The hatchlings from this clutch will be adopted out to area K-12 teachers and students with the help of the High Desert Chapter of the California Turtle and Tortoise Club and will find their way into a classroom to be apart of our developing "tortoise in the classroom" project. To learn more about how to take care of a Desert Tortoise in the classroom visit this link and navigate to "Captive Care". If you are interested in adopting a tortoise, call Judy Roger, Adoptions Chairperson for the the High Desert CTTC, at (760) 243-4518.

SCIENCE STANDARDS: This WebQuest has been designed to specifically address the High School California Academic Content Standards for Biology/Life Sciences stressing the science and study of Ecology. This standard specifically states that the…

6. Stability in an ecosystem is a balance between competing effects. As a basis for understanding this concept, students know:

a. biodiversity is the sum total of different kinds of organisms, and is affected by alterations of habitats.

b. how to analyze changes in an ecosystem resulting from changes in climate, human activity, introduction of non-native species, or changes in population size.

c. how fluctuations in population size in an ecosystem are determined by the relative rates of birth, immigration, emigration, and death.

d. how water, carbon, and nitrogen cycle between abiotic resources and organic matter in the ecosystem and how oxygen cycles via photosynthesis and respiration.

e. a vital part of an ecosystem is the stability of its producers and decomposers.

f. at each link in a food web, some energy is stored in newly made structures but much is dissipated into the environment as heat and this can be represented in a food pyramid.

g.* how to distinguish between the accommodation of an individual organism to its environment and the gradual adaptation of a lineage of organisms through genetic change.

TASKS: Stability in an ecosystem is a balance between competing factors. The student's task will be to determine and describe a healthy, stable ecosystem that can support a viable population of “introduced” captive raised tortoises and/or their unhatched eggs. In order to accomplish this task each student will need to: 

Ø      Determine and describe the taxonomic classification (Kingdom à species) for the kind of tortoise being raised in the classroom.

Ø      Determine and describe what this kind of tortoise needs to survive, grow and reproduce in a natural ecosystem.

Ø      Determine and describe the abiotic and biotic factors that will influence the fluctuation of a population of captive raised and wild tortoises if they are to be reintroduced back into their natural habitat.

Ø      Determine and describe the role captive or wild tortoise will play in the cycling of energy and matter (carbon, oxygen, nitrogen) whether they live in a domestic setting or are free ranging "wild tortoises. in their terrestrial ecosystem?

Ø    Determine if the captive raised desert tortoises and/or their eggs should be released back into the wild.

SITUATION: It is June, the summer after your sophomore year at the University of California in Riverside. Your major is biology. You have just begun a summer internship with the California Department of Fish and Game (CDFG). Since your home address is in the Mojave Desert, you have been assigned to region 6, the “Inland Deserts” district of the CDFG.

Judy, your supervisor, has been busy all year participating with a statewide team of wild land managers to develop the “West Mojave Coordinated Management Plan”. The day you arrive she receives the following request from her supervisor in Sacramento:

“We need to know if a captive raised Tortoises and/or their unhatched eggs can be/should be repatriated back into the open Mojave Desert to help bolster the number of a declining population in the wild. A preliminary findings report is needed in Sacramento by July 1^st."

Because of her other time commitments, Judy decides to make this task your internship project. Giving you a couple of examples of other “preliminary finding” reports, you and Judy put together a rough outline of information that will be needed in the report:

SECTION 1: Title Page, Abstract and Problem Statement

1.      Title Page

a.     Title page consists only of:

• a descriptive title for the report,
• author's name, and
• the reports completion date.

2.      Abstract

Separate page abstract clearly summarizes the significant findings and preliminary conclusion in less than 200 words. Don’t mention anything in this section for the first time.

3.      Problem Statement

a.      A problem statement is brief and concise, clearly stating the problem that is being addressed.

b.     Include just enough background information to establish the importance for arriving at a solution or best finding.

SECTION 2: Review of Literature

1.      Tortoise Taxonomy: (4 or fewer paragraphs and an illustration)

a.      What is a tortoise? What kind of tortoises are native to the southwest, specifically the Mojave Desert?(one paragraph with an illustration)

b.      How are is the tortoise that is native to the Mojave Desert different from other tortoises? (one paragraph)

c.      What kind of tortoise is native to the Mojave Desert? Identify as many common and scientific names for this kind of tortoise as possible. (one paragraph)

d.   Illustrate the taxonomy of the “tortoise” that is native to the Mojave Desert. In the illustration include some examples of other tortoise ”kinds” that are closely related to the tortoise native to the Mojave Desert at the “family” and “genus” level of classification.

 Before conducting your research for this section of the report, review your notes and read (skim over) chapters __ and __ in your textbook (Biology: The Dynamics of Life, © 2002).

2.     Tortoise Life Cycle:

a.       Describe and illustrate the life cycle of wild Mojave Desert tortoise. (4 or fewer paragraphs with an illustration)

b.      Describe the stage(s) of this life cycle that is most sensitive to environmental change and why that is. (4 or fewer paragraphs with an illustration)

3.      Healthy Desert Habitat:

a.      What are the abiotic requirements needed to support the species before, during and after spawning. List and describe each requirement. (Where possible, research and find the “limits” or “range of tolerance” for each requirement that you identified.) (6 or fewer paragraphs)

b.      What are the biotic components needed to support the species (after the eggs have hatched). List and describe these components. (6 or fewer paragraphs)

c.      What are the biotic components of a tortoise’s environment that it must avoid in order to survive? List and describe these components. (4 or fewer paragraphs)

d.      What are the biotic components of a tortoise’s environment that aide in recycling its matter back into the greater ecosystem? List and describe these components. (6 or fewer paragraphs)

e.      Construct a chart and classify the biotic components you identified above as producers, prey, predators or recyclers. (2 or fewer paragraphs with a chart)

Before conducting this next two searches, read section 2.2 Nutrition and Energy Flow in your textbook (Biology: The Dynamics of Life, © 2002).

4.      Tortoises and Regional Biogeochemical Cycles: How do carbon, oxygen, and nitrogen cycle through tortoises?

a.      Identify major carbon sources that tortoises rely upon for their survival. Briefly describe the role carbon plays in tortoise anatomy (structure) and physiology (function). (3 or fewer paragraphs)

b.      Identify major nitrogen sources that tortoises rely upon for their survival. Briefly describe the role nitrogen plays in tortoise anatomy (structure) and physiology (function). (3 or fewer paragraphs)

c.      Identify major oxygen sources that tortoise rely upon for their survival. Briefly describe the role oxygen plays in tortoise anatomy (structure) and physiology (function). (2 or fewer paragraphs)

5.      Energy Flow: (4 or fewer paragraphs with diagram)

a.      Where in the “cascade” or flow of energy from the Sun to the vastness outer space do tortoises fit?

b.     Capture in a detailed and labeled diagram tortoise’s place in the ”cascade of energy”.

SECTION 3: Field Data

1.      Current & Historical Information: Abiotic Factors

a.      Describe the maximum, average and minimum temperature in selected location across the tortoises Mojave Desert home range.  This web site might be helpful: http://wgsc.wr.usgs.gov/mojave/climate-history (1 paragraph)

b.      Using information gathered in section 3.1.a, and available data or data freshly collected from your fieldwork, describe if repatriated tortoises and / or their eggs could survive in Mojave Desert landscape surrounding the Mojave River Campus of the Academy for Academic Excellence. Address any seasonal variations that might effect survival. (4 or fewer paragraphs)

2.      Current & Historical Information: Biotic Factors

a.      List and describe other terrestrial animal species that currently reside on or adjacent to the Mojave River Campus or have been identified by other as living in the here. (1 paragraph with a table)

b.       Determine if introducing tortoises and/or their eggs to the Mojave River Campus wildlands would jeopardize the survival of the existing animal residents . (4 or fewer paragraphs)

c.     Determine if the eating habits of repatriated tortoises would jeopardize the survival of any native flora or fauna. (4 or fewer paragraphs)

3.      Natural Reproduction Viability

Using information gathered in section 1.2.a-c, and available data or data freshly collected from your fieldwork, describe if the eggs laid by captive raised Tortoises should repatriated back into the wild (i.e. Mojave Desert). Address situation that might effect survival of the receiving population or of the repatriated tortoises. (4 or fewer paragraphs)

SECTION 4: Significant Findings & Preliminary Conclusion

1.      Compare the findings collected in your review of literature to what you learned about the "terrace" habitat and the surrounding desert and its inhabitants and highlight any important findings specific to the question of “should captive raised tortoises and/or their eggs be released or repatriated back into the Mojave desert.”  (1 paragraph)

2.     Give a preliminary answer to the question, “should captive raised tortoises and/or their eggs be released/ repatriated back into the Mojave Desert?”, and support it using findings gathered and stated in the report. (1 paragraph)

AVAILABLE RESOURCES: Besides making books in her field office’s library available to you, Judy has provided you with the following list of web resources that she uses when preparing similar reports. She also suggests that you check out resources that are available at local libraries and turtle and tortoises clubs in your community to help you with your task.

Judy’s Web Resource List:

Some of the following web sites will require that you download Acrobat Reader. It can be downloaded for free @ http://www.adobe.com/products/acrobat/readstep2.html

Links to Resources that support Mojave Desert Studies

• http://hegel.lewiscenter.org/users/mhuffine/subproject's/Instructor/IPBIO%20Main%20Page/mrss_MojDesCol.htm
• Desert Animal Survival Adaptations

Tortoise Information, Organization supporting research

• The Desert Tortoise Council
• Desert Tortoise Project, The Redlands Institute (current and past projects)
• California Turtle and Tortoise Club
• Tortoise Trust
• EMYsystem, Global Turtle/Tortoise Conservation database
• TortoiseAid
• Tortoise Group, Nevada
• The Desert Tortoise Preservation Committee
• Desert Tortoise Hub
• Turtle and Tortoise Owners Discussion Groups
• California Wildlife Habitat Relationships System ~ Desert Tortoise
  California Department of Fish and Game, California Interagency Wildlife Task Group
• Mojave Desert Tortoise GATF Project: Desert Tortoise Ecology
• Joshua Tree Kids Club Presents: HANDS OFF PARDNER!
• Desert Tortoise Research at WERC
• Answering Questions about Desert Tortoises
  • http://www.tortoise-tracks.org/gopherus/tortques.html
• List of links supporting tortoise research
• Some Notes on the Desert Tortoise (helpful)

Tortoise Taxonomy, Tortoise Identification, Distribution

• Tortoise Phylogentics
• An Online Taxonomic and Geographic Reference
• The Sonoran Desert Tortoise (about a book)
• Draft Desert Tortoise Taxonomy and basic ecological information

Tortoise “Kind” Gallery

• California Turtle and Tortoise Clubs Gallery

Tortoises of North America

• Neararctica
• Turtle & Tortoise list

Tortoise Biology

• Turtle Anatomy
• Turtles in the Past
• Tortoise Reproduction Biology
  • Studies of reproductive output of the desert tortoise at Joshua Tree National Park, the Mojave National Preserve, and comparative sites http://www.werc.usgs.gov/hq/pdfs/parksci.pdf
• Desert Tortoise Burrows
• Potential Impacts of Captive Pet Tortoises on Wild Populations
• Field Survey Protocols for any Federal Action that may Occur within the Range of the Desert Tortoise

Genetic Studies

• Analysis of Gene Flow Among Sonoran Desert Tortoise Populations Using Molecular Techniques and Radiotelemetry
• Society for the Study of Amphibians and Reptiles

Tortoise and Turtle Enhancement Programs

• Tortoise Conservation links
• Potential Assets and Liabilities Inherent to Desert Tortoise Hatchery Nurseries
• Mycoplasma agassizii sp. nov., isolated from the upper respiratory tract of the desert tortoise (Gopherus agassizii) and the gopher tortoise (Gopherus polyphemus).
• Predator-Proof Field Enclosures for Enhancing Hatching Success and Survivorship

Habitat requirements

Diet

• Diet: recommended plant list
• Known plants that can poison captive tortoise
• Diet and Growth
• Summary of scientific findings (including compositional studies of wild DT scat)

Tortoise Habitat Gallery

• USGS, Desert Tortoise Habitat Modeling (On-going Research)

Desert Food Webs & Chains

• A good place to start to understand the DT's place in a food web or chain...
• Desert Tortoise and the Early People of the Western Deserts
  • Tortoise Predators
    • http://www.deserttortoise.org/abstract/abstracts2001/2001abs39.html
    • http://www.ca.blm.gov/elcentro/limited_use.html
    • http://www.death-valley.us/article690.html

Tortoise Ecology / Biotic components

• General description of DT biology and ecology (detailed) PDF

Tortoise Ecology / Life Cycle

• Life Cycle of the Desert Tortoise

Mojave Desert Wildlife

• http://www.natureali.com/mojave.htm
• GIS Data base information
• Animals and Plants of the East Mojave
• Animals and Plants of the common along the Mojave River

Information Data Bases

• BLM’s California Desert District
• Turtle & Tortoise Links
• EMY System

Mojave River Weather Information

• Current and archived weather data @ the Lewis Center's Mojave River Campus
• Mojave Climate Data, Western Regional Climate Center

Collecting Data at the "terrace" and in the surrounding desert

• For more information, e-mail Mr. Huffine @ mhuffine@lcer.org or call @ 760-946-5414 ext. 238

PROJECT EVALUATION: Judy, your CDFG internship supervisor uses a rubric to evaluate her work before sending it on to Sacramento. She will be using the same rubric to evaluate your draft. Your summer internship program grade with the university will depend on her assessment. The rubric that she will use is as follows: