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Ecology


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Notes on the Lab Report Write-up comparing Barbara’s Lake (a natural lake in Laguna Canyon in orange county California)
and a human-created lake in William R. Mason Regional Park in Irvine orange county California
This study is a comparison of Barbara’s Lake, the largest of the three Laguna Lakes in Laguna Canyon and the only
surviving “natural” lake in the County, with a human-created lake in William R. Mason Regional Park. Your comparison
should focus primarily on the differences between the natural and artificial lakes. As with your first lab report, you
should plan to discuss both abiotic and biotic conditions of the two lakes and describe how the different factors
contribute to each lake as an ecosystem. In addition, you will be able to compare your data from Barbara’s Lake with an
earlier study done by James Needham in 1924.
• You are expected to formulate a hypothesis that relates to the comparison between the two lakes. You need to do a
T-test to get the P value and you need to show your work. You need to use the data for both weeks in order to have enough
data to do the T-test.
• Your report should be 5 pages long, and should include the following sections:
Abstract: A succinct discussion of all the major parts of your report. [Your abstract should be a summary of your paper.
To be safe, make sure it’s a 1-2 sentence summary of each of your paper’s sections]
Introduction: Introduce the context of the lakes, the lakes themselves, the details of your study, and clearly state your
hypothesis. [Frame your work in some broader context. It isn’t enough to simply say that you’re comparing a natural and
an artificial look to see if and how they are different. You need to provide sufficient context to give your work some
sort of broader implications (Why it’s important and how your work can affect how we look at the things you tested in
this area and other areas)]
Materials and Methods: Describe all the relevant methods used to obtain your data. [If those data are reported in the
data section, the methods must mention it! BEWARE if you missed points for that last time.] It might help to organize
this section with a couple of subheaders. Make sure to include the statistical analyses you did.
Data: Describe the relevant trends in your data. [You should have two tables: one for Mason Park and the other for Laguna
Canyon. Each table should have data from both days of the visits, your group and the other group’s day. When discussing
trends, compare both lakes using average values for clarity and simplification.]
Discussion: Discuss what kinds of conclusions your data supports, describe how your data illustrates differences between
the two ecosystems; and, consider the differences between your observations at Laguna Lake with those taken by Needham in
1924 in order to compare you need to do the T-test and get the P value and discuss the data and numbers and compare them
and say if there is any significant difference between the two lakes. [Be sure to discuss all trends and patterns seen.
These should be the ones stated in the data section. Also, don’t forget to discuss the differences between your
observations at Laguna Lake with those by Needham in 1924 means the vegetations and if they are oligotrophic or
eutrophic.]
Think carefully about organizing your discussion section. Start off the discussion with a general statement to remind
your reader what you are studying (Don’t go straight into a sentence such as “DO was higher in Pond X than Pond Y). Also
try not to end abruptly on a sentence such as the one above, wrap your discussion up with a brief summary/
implication/future work sentence.
Table: You are required to provide a table of data. [For both lakes for both days. Figures are optional and not
required.] Make sure to include a table caption at the top of the table. This should be a brief description of what is in
your table.
Works Cited: You are required to cite a minimum of 4 sources – our webpage resources will help with this. At least 2 of
your sources must be published scientific peer-reviewed journals.
Additional Notes:
In 1924 James Needham, a famous limnologist and wetland ecologist, studied the (then 3) Laguna Lakes, including
Barbara’s Lake, which we visited. His study (Needham, 1924) allows us to compare what we find with his descriptions of
lake conditions and wildlife 91 years ago. We will also be able to compare two morning and afternoon of our own data
sets with each other. Today there is only one lake, Barbara’s Lake, which we visited on Monday, April 27 and Monday, May
4, 2015.
The lake in William R. Mason Regional Park was created in 1978. See the Park’s website at:
httpss://www.ocparks.com/masonpark/
This much appreciated 345 acre Regional Park is near UCI, and among its use restrictions are no wading or swimming.
Thus, our sampling will be restricted to what we can reach from the bank.
For Barbara’s lake at laguna canyon these are the helpful websites:
httpss://socalhiker.net/hiking-ridgeline-loop-to-barbaras-lake/
httpss://www.caopenspace.org/barbaraslake.html
This paper should have an hypothesis – perhaps something like – the ecological and physical conditions of a
natural lake are very different from those of a created lake. The null hypothesis might be that there is not detectable
difference.
Some of the things to keep in mind when comparing Needham’s early study with the present situation in Barbara’s Lake are:
– his study was conducted in the late summer
– Lake 1 (dry in this drought) was by this time like a green soup, while Lake 3 (= “Barbara’s Lake”) was clear – it was
murky during our visits
– exotic animals either deliberately introduced or just invaders since Needham’s time include the South African clawed
frog, red eared slider, and the bullfrog; mosquito fish and catfish; the impact of severe overgrazing was not as big a
problem in the early 1920s as was since then; grazing has been terminated, so now we are in a period post-grazing
recovery
– and, of course, the retirement community of Leisure World contributes polluted water continuously into Barbara’s Lake
(“Lake 3”)
– Laguna Canyon Road was re-located to keep its impacts away from the Lakes – the current parkway has four lanes and
doesn’t abut Barbara’s Lake
– Needham found a very different invertebrate community (including 3 new species) than exists in the lakes today
-Because of grazing, sediment shedding was probably much greater in the past 50 years (no grazing now) than in the 1920s
Keep in mind that Needham was a tremendously gifted invertebrate/wetland specialist – he would always find more than we
would (and he could identify it).
This paper should have an Abstract, Introduction, Materials and Method, Results and Discussion, and a Literature
Cited section.
Photographing or sketching a site is extremely useful – it reminds you of what you saw and allows you to point
specifically to things you wish emphasize (emergent vegetation, water color, a bird, surrounding vegetation, and so
forth).
A map is useful to indicate exactly where on a lake you did your sampling. Provide complete captions for all
Tables, and then cite every table you use.
Here is the citation for the Needham paper, which has been posted on our website:
Needham, J.G. 1924. Observations of the Life of the Ponds at the Head of Laguna Canyon. Pomona Journal of Entomology and
Zoology 16: 1-12.
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