Week 13 - Packrat Middens

This week we'll be reading:

Smith, Felisa A. and Julio L. Betancourt. 2006. Predicting woodrat (Neotoma) responses to anthropogenic warming from studies of the palaeomidden record. Journal of Biogeography 33: 2061-2076.

You might recognize the name of the first author as our official faculty member, Felisa! This is a paper on using middens to study how packrats have reacted to changing temperatures over time.

This paper focuses on using fecal pellets to study body size change in the woodrats. Traditionally the data sources from packrat middens are plant macrofossils and pollen. These are analyzed in a similar way to pollen from lake cores that we discussed earlier in the semester. We'll talk about using these data in class.

Packrat paleomiddens can also contain other material from the environment, such as archaeological artifacts, bones, and teeth. I'll probably throw in some teeth, since that's what I study for my research.

For our discussion on Thursday, I want you to start thinking about designing studies of your own. How has climate change affected species and ecosystems in the past? Design a study and post it in the comments.

Week 12 - Tree Rings

This week we'll be reading:


Li, Jinbao, Edward R. Cook, Rosanne D'Arrigo, Fahu Chen, Xiaohua Gou, Jianfeng Peng, and Jianguo Huang. 2008. Common tree growth anomalies over the northeastern Tibetan Plateau during the last six centuries: implications for regional moisture change. Global Change Biology 14: 2096-2107.


This week, when you are reading the paper about tree rings and climate in Tibet, be thinking about how those methods could apply to other studies.  Last week, we had a good discussion regarding the collapse of Copan.  If you were to conduct a study using tree rings and similar metrics to those used in the Tibet study, how would you apply those to Copan to answer hypotheses?  What other metrics would be useful?  Be specific about your hypotheses and sample sizes and describe what your hypothetical dataset would look like.  What other forms of data would be useful to determine the Copan collapse?  Think of at least three.  Be prepared to discuss your hypothetical experiment and blog post and have the class scrutinize them like we did for the palynology paper last week!

Week 11 - Palynology

This week we're learning about using pollen records to learn about paleoclimate. We'll be reading:

McNeil, Cameron L., David A. Burney, and Lida Pigott Burney. 2010. Evidence disputing deforestation as the cause for collapse of the ancient Maya polity of Copan, Honduras. PNAS 107:3, 1017-1022.
(Note that on the wiki, the paper is listed as McNeil et al 2009 - this is a typo.)

As you read this paper, think about how the data are analyzed and interpreted. What, if anything, would you have done differently with the pollen data?

Week 10: Fires, Landscapes and Climate

This week we will be investigating how changes in climate can affect the landscapes that we observe and also how landforms can be useful in understanding past climate.  In particular we will be looking at fire events.  In a changing world where the frequency of large stand replacing fires appears to be on the rise there is a need to understand how "abnormal" these fires are (Whitlock, C., 2004. Forest, fires and climate. Nature, 432, 28-29. This is posted as an intro to this week's topic).

The primary reading this week will focus on fire records from the Sacramento Mtns in southern New Mexico and is written by UNM folks!

Frechette, J.D., Meyer, G.A., 2009. Holocene fire-related alluvial-fan deposition and climate in ponderosa pine and mixed-conifer forests, Sacramento Mountains, New Mexico, USA. The Holocene, 19(4), 639-651.


It is about 10 pages, but there are lots of figures.  Pay attention to what the figures are trying to tell you as you read. Enjoy!

The Whitlock paper is optional, but highly recommended as a short, concise intro to the topic. It is posted on the wiki along with the primary reading.

For your blog post prior to Thursday's class here are a few questions to consider in your response:

1. What was one thing that you found interesting in the paper?
2. Is there one thing that you have questions about after reading the paper?  What were you confused by or feel you need more information about?
3. Were you convinced by the story that the authors proposed in the paper?  Why, why not or why maybe?  Be specific.

Final Project Discussion

Hey folks, it's finally time to start working on your final projects! I have posted the guidelines for your projects on the wiki. The gist is, you need to do an original analysis of freely available data or do a meta-analysis related to climate. I'm posting this entry so you can kick around ideas and ask questions in the comments. I hope you'll all keep an eye on this entry and help each other out.

Week 9: Microwear and Climate Change

Hey folks,

This week I want to do a special prompt for our blog discussion.  Of course, you may, as usual ask and answer questions about this week’s article on microwear, but I thought it’d be really fun to continue a discussion on current climate changes, its effects, and how we as a scientific community interpret and convey our results to the general public.

On last week’s blog, Mike provided some very extensive and excellent research articles regarding current mass extinction.  However, since I am a firm advocate of the scientific method and a proponent of questioning any study under the name of science, I’d like to play devil’s advocate for a moment and pose a few thoughts in response to the assertion that we are currently undergoing a mass extinction:

1)      The fossil record is not always a good proxy for past environments.  Barnosky and colleagues exclusively looked at mammals, citing that, on average, over the past 65 million year only 2 species per year went extinct.  Personally, I am a little concerned about this assumption because there is an obvious bias toward preservation of larger mammals over smaller and I believe it impossible to know the extinction rate of some of the smaller fauna not preserved in the fossil record (this is particularly pertinent since smaller mammals generally have a faster species turnover, fast-slow continuum anyone?).  Although the authors address this problem in their article and state our incomplete knowledge of extant species, I still believe these two records are not quite comparable.

2)      Some species have responded already to current climate change and I believe we will continue to see some species adapt and (potentially) a decline in the rate of extinction . Here’s just a short little review artcile on the subject from 2002, I’m sure much more has been explored since then: http://eebweb.arizona.edu/courses/Ecol206/Walther%20et%20al%20Nature%202002.pdf .  I also came across this article: http://www.law.arizona.edu/AdaptationConference/PDFs/ParmesanAREES_Impacts2006.pdf which, while it definitely emphasizes concern over the ability of animals to adapt sufficiently to climate change and  is a nice (albeit longer) review.

3)      Although I noticed that many of the articles mentioned in last week’s blog deal with increased rate of extinction in individual species(which I by no means doubt, I believe we have ample evidence), only a few deal with mass extinction, which is a whole other animal.  While I do believe that theoretically we could be heading in that direction, the studies explicitly dealing with mass extinctions are still projections. The actual rate of extinction, all animals taken together, is still not near the landmark of 75% of all species eliminated at the moment.    When all is said and done, we cannot be certain which animals will be able to exploit these new habitats and what new species will develop from this event (and believe me, a lot more research effort has been focused on looking at extinction, not speciation). I have no doubt that species diversity will decline (and has!) but I am still unconvinced it is on the level of a mass extinction at the moment.  I have a hard time accepting Barnosky’s assumption that threatened means inevitable extinction in the near future. However, I agree, without conservation efforts for threatened species, we are more at risk of entering a mass extinction.    I personally think we should continue conservation efforts full-force, but I do not believe there is ample evidence to call our current state a mass extinction (at the moment, though I’m open to having my mind changed with sufficient evidence). ….though I am considerably more worried about amphibians and coral now…

As I said, I am primarily worried about agriculture and while I by no means think we should flout conservation efforts, I do think we should address agriculture.  I turn it over to the peanut gallery though, what concerns you most and why?  If you want to debate my questioning of the mass extinction, I encourage it! Think of this as a free forum for the rest of the semester to discus climate change and its impacts.  Here’s a few questions to kick you off:

1)      What concerns you most about our current climate change?  (articles are always encouraged!)  Be ready to defend your answer…there are always multiple sides to one story and, as scientists, we must be as impartial as possible…..which means we’ve got to play devil’s advocate to our own initial proclivities.

2)      Whether we are going through a mass extinction or not, I have mixed feelings on the way it should be conveyed to the general public.  Sometimes a more extreme prompt can be very encouraging for change (which, of course, is a good thing!) though, unfortunately, sometimes it can have the opposite effect of isolating more conservative-minded folk who don’t put as much stock in science.  How do you think we should convey current issues to the general public?

3)      As students of science (who I hope will continue to be actively involved in looking at global climate change….and coming up with a few solutions…) how do you think we should approach climate change effects in the future?  

As always, you guys may discuss this week’s article as well…impressions, concerns, ideas for future research, I’m all ears!

Have fun and see you all on Thursday for some more fun with microwear!

Katie

Isotope Projects

Hey Folks! Sorry for the delay! Your isotope project descriptions and data are now posted on the wiki page.

Readings for the week after spring break are also now posted.