I've been kicking a few ideas around for the independent project. Ideally, I was hoping to be able to analyze some of my own data. However, the data I collected last summer has already been analyzed as fully as I believe it could/should be. I'll be collecting more data over spring break, but I'm concerned that will be too late to begin the project.
Instead, I think I'll work with the niche breadth and complementarity dataset of Tom's, which I began working with last fall but was put on hold while we waited for some samples from Tom's former advisor. The dataset includes information on foraging height, arthropod species consumed, habitat, maneuvers used, substrate, et al. for about a dozen species of rainforest-dwelling insectivorous birds in Costa Rica (mostly in or near La Selva). We're testing to see whether there is an inverse relationship between habitat and food specialization in this guild resulting in niche diffferentiation. That is, we expect that species that consume similar diets will be separated spacially (by habitat, height, etc.) and vice versa. We intend to combine this with a phylogenetic analysis (perhaps phylogenetic independent contrasts? need to look into this further) to identify which differentiation (habitat vs. food) developed first - the prediction is that similar species will differentiate spatially fairly rapidly, while specialized food habits will take longer to involve.
We plan to test this using Mantel tests, which can be run using an add-on package for R which you can download from CRAN. I haven't looked into this yet, but had good success with the VEGAN package which I used last summer, and I expect this will be similar.
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4 comments:
woah!
phylogenetic analyses and mantel tests are well beyond the scope of this course :) are you sure you're not going to be bored with us?
that said, i think it sounds like a great project and i'm happy to help in any way i can. and it might conceivably be useful to you to try to explain what you're doing to an audience whom you can assume will follow some of what you're doing but will need help with other parts. e.g. relating mantels to correlations among scalars.
also, i don't know if it'll help or not, but here's a paper in which i coincidentally use both mantel tests and a phylogenetic regression (~ p.i.c.s):
http://www.tulane.edu/~guill/Reprints/Guill_et_al_Syst_Biol_2003.pdf
Thanks for the paper - I don't know too much about either phylogenetics or Mantel tests at this point. That's why I'm taking Darwin's class, and I'm very glad to know that there's someone here who knows about Mantel tests (watch out, I'm sure I'll be questioning you about them often!).
I figured that this project was more than was typically expected, but I need to get this project done, so this will give me further impetus to wrap it up this semester. I won't have any unanalyzed data of my own until late March/early April, and I would rather put the time and effort in on something that can be published, rather than just "playing" with a dataset for the purposes of this class.
Wow! This all seems very interesting and complex. It is cool that you work with Tom though, he is really great! Cool picture by the way. It makes me want to visit Costa Rica.
Hi Nicole,
I really like the sound of your project, it reminds me of something I studied in Ecology. I can't remember the name of the guy who studied niche partitioning of birds in trees. He is pretty famous, you probably know who I mean. Also, I love your blog, I wish I had more time to really get into writing up what we have covered in class. are you writing all this straight from your memory?? If, so, then Im really impressed!!!
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