While there is a saying that a butterfly can affect the creation of hurricanes, the reverse is definitely true–climate change can affect butterflies. In yesterday’s Randall Women in Science seminar series, Camille Parmesan (a University of Texas Austin lepidopterist and lead author of the IPCC that won the 2007 Nobel Peace Prize along with Al Gore) discussed the actual data in her lecture “Responses of Wild Life to Anthropogenic Climate Change: The Limits of Adaptation and Potentials of Ecosystem Restoration.” (Aside: The following includes my notes and recollections of the lecture. Any mistakes are my own and if anyone has addenda and corrections, please let me know.)
Despite this year’s bout of freak winter weather in the U.S., global mean temperatures have definitely increased in the 2000s compared to the 1990s. In fact, 2009 is the fifth hottest year on record. If one calculates this out, it’s about 0.7 degrees Celcius increase since 1900.
“Pah!” you might say. “0.7 degrees is nothing! I can’t feel the difference between, say 40 and 41 degrees.” Well, that 0.7 degrees has already had a profound ecological effect. It’s hard to see that if you’re mostly stuck in the temperature controlled suburban indoors. But in the field, it’s a different story. For example:
*Mismatch of trophic levels. Because of the increase in temperature, spring events have started to shift. In temperate northern climes, that’s a mean advance of 2.8 days per decade. This means that animals, such as amphibians and butterflies, are beginning their breeding cycles earlier and at a faster pace than plant life cycles. Eventually, there’s going to be a complete mismatch of the life cycles of animals and their food sources, thus putting the viability of those animals at risk.
*Habitat ranges are shifting northward and upward. Because a species’ historical habitat is becoming warmer, the species will naturally move north and to higher altitudes. Not all species will move north, though, and as a result, the entire range will decrease as the southern part of their range contracts. And there’s only so much you can go up as mountains are finite. In a couple of range studies done in Europe (where species surveillance is far more extensive than the U.S.), 65% of the species surveyed had colonized northward and 22% had contracted southern ranges.
*Community turnover. In a Nature study done by Parmesan, over 1,700 plant and animal species were surveyed worldwide. 62% of those species responded to temperature change and 52% changed where they lived. Because there was such variability between species, this means that there’s going to be a change in communities. That is, a particular ecosystem isn’t just going to shift a couple kilometers north. Animals and plants will respond differently so that it will be more of a staggered move. Different species that had never had contact with each other before will start sharing the same habitat and who knows what sort of interaction they will have.
*Expansion of disease range. Just because an oyster population, say, moves a couple hundred kilometers north, does that mean that species’ associated diseases will stay put in the old spot. The parasites will move with their hosts. And as they move to new locations, they will come in contact with new hosts that have yet moved with no developed defenses.
*Declines and range contractions of sea ice species. Take the prime example of the polar bear. Yes, its icy habitat is shrinking. But so is its food source. Polar bears require two kilograms of fat a day. If seals were still around, their nutritional needs would be met. But due to the decrease in seals, polar bears are now forced to hunt terrestrial animals which don’t have enough fat. Also, because it isn’t cold enough, the dens that pregnant females make are collapsing, killing the bears–further decimating the population.
*Climate change affects the nutritional value of food. One example is the koala. Increased carbon dioxide levels wreak havoc on the biochemistry in eucalyptus plants–the sole food of the koala–rendering the plants less nutritious. As a result the koala population is suffering from malnutrition.
*Humans are affected, too. In the northern polar region, native populations are having a harder time hunting traditional foods–so their diets have literally changed from seal to frozen pizzas. Seasonality is compressed and permafrost is being lost. Vector borne diseases are shifting north and infestations normally killed by the cold are now thriving.
*There are no genetic changes. One argument is that species are moving northward because there’s evolution happening, that these species are learning to adapt to a colder environment. This is not so. Analysis of species’ genomes have not revealed any genetic change that would help the animal or plant tolerate a temperature change. It is the temperature change itself that appears to be the likely culprit for species translocation.
Dr. Parmesan seemed skeptical that anyone will be reducing their emissions any time soon. In fact, she was resigned to the fact that global temperatures will rise in the foreseeable future. However, she pointed out some possible solutions (which might cause invasive species purists to go crazy): 1) assisted colonization or moving species outside of their range in anticipation of the range change; 2) restoration of historical habitats; and 3) creation of new habitats adapted to the future climate.
(note: some articles may require subscription or registration)
*Singer MC. “Complex Components of Habitat Suitability within a Butterfly Colony.” Science, Volume 176, Issue 4030, pp. 75-77 (abstract and full text)
*Fleishman E, Austin GT, Weiss AD. “An Empirical Test of Rapoport’s Rule: Elevational Gradients in Montane Butterfly Communities.” Ecology: Vol. 79, No. 7, pp. 2482-2493. (abstract and full text)
*Parmesan C, Yohe G. “A globally coherent fingerprint of climate change impacts across natural systems.” Nature. 2003 Jan 2;421(6918):37-42. (abstract and full text) (pdf)
*Seimon, TA et al. “Upward range extension of Andean anurans and chytridiomycosis to extreme elevations in response to tropical deglaciation.” Global Change Biology. Volume 13, Number 1, January 2007, pp. 288-299. (abstract and full text)
*Kunkel KE, Changnon SA. “Climate-Years in the True Prairie: Temporal Fluctuations of Ecologically Critical Climate Conditions.” Climatic Change. Volume 61, Numbers 1-2 / November 2003, pp. 101-122. (abstract and full text)
*Crozier L. “Winter warming facilitates range expansion: cold tolerance of the butterfly.” Oecologia. Volume 135, Number 4 / May 2003, pp. 648-656. (abstract and full text)
Question and Answer Session (Paraphrased)
Q: Aren’t there going to be unintended side effects to this ecosystem engineering?
A: Since there’s global warming already, there’s going to be a risk either way–whether you do nothing or engineer new ecosystems for species.
Q: Aren’t other places already considering habitat restoration, except with a monoculture? They might want to restore the Native American Prairies, but it would be easier just to plant one type of grass.
A: Yes, but conservationists will have to partner with industry if we want to keep biodiversity rather than just planting another crop.
Q: What exactly is an ecological community? And are people accepting of it?
A: Communities are dynamic and not stable. Idealy, it would be made up of species that are historic to that habitat and species with foreign genotypes for diversity. It would be interesting to introduce historic species and alternative species and see who wins. It also takes a lot of money to establish a community. Right now, there’s a community project going on in Copenhagen.
Q: Are climate models accurate enough so that we could already change habitats, say in the Palouse?
A: It depends on the geographical area. If the models are consistent for that particular geographical area, then yes. But if the models are conflicting, it is probably better to stick with traditional conservation.
Q: What about the “unseen majority”? How does climate change affect prokaryotes?
A: There’s some experimental data, such as on soil microbes, but not on the scale of animal studies. (So the answer to this, currently, is unknown.)
* * *
Twelve other graduate students and I were also lucky enough to attend a dinner with Dr. Parmesan. She mentioned that as a scientist, it’s somewhat frustrating going to climate change meetings. First, there are very few scientists who end up influencing policy. Mostly it’s politicians. And usually it’s the person who has the most endurance, i.e., the person stands and talks the longest. No matter your ideas, if you don’t have the endurance, you’re probably not going to be heard. Second, it’s difficult to get moving on solutions to the climate change problem because no one thinks long term. Politicians maybe think two years ahead–to when they’re re-elected. Industry doesn’t think much longer than that either–it’s concerned about profit and loss, not what is going to happen fifty or a hundred years in the future.
Dr. Parmesan also had several observations about being a woman in science:
1. In a Berkeley study, it was found that the person who did best in science was a married male with family. Why? Two reasons. One, the married male with family had a support group (spouse and kids–not just the spouse) who helped him roll with the punches–as opposed to single scientists of either gender. Two, the married male with family had more downtime available than his female counterpart who ended up doing the majority of the domestic chores along with her career. Downtime is critical for recharging energy and creativity for the career.
2. Take away from above study: If you’re a married woman with kids, make your husband do at least half of the housework.
3. For couples who, on the surface, appear to have everything from career to kids, it actually isn’t everything. Both the man and the woman in the relationship will have made certain sacrifices in order to get their lives at that point.
4. A woman shouldn’t compromise if she wants to further her career. Dr. Parmesan was fortunate in that her husband was willing to leave his career to go with her if she found a professorship elsewhere. Currently, she is very disappointed that all of her female grad students have decided to follow their husbands and settle for less rewarding jobs.
5. Being female in science isn’t really that much harder than being male. It’s just different. Women might worry about kids, but men have stuff to worry about, too. Case in point–
Dr. Parmesan related an anecdote during her time as a post-doc at an ecology center in California. The center held a number of workshops which she attended. Typically in these workshops, no one really knew each other beforehand. She noticed that in seminars attended by at least 30% women, there was a lot more collaboration and an air of wanting to get things done. When there were less than 30% women, the first day of the workshop became totally useless as the male scientists tried to one-up each other on who was right or wrong. Every time she would try to say something, they would totally ignore her.
She was very frustrated with this until she talked with a transgendered scientist who gave her some insight into the male psyche. Males need to establish a hierarchy first; females at this point are irrelevant. In order to do so, they engage in behavior that is very similar to macho tennis players lobbing balls at their opponent. Once they establish the hierarchy, then things will go back to normal. So Dr. Parmesan tried this–in workshops dominated by men, she would simply sit and listen on the first day while the men fought for dominance. On the second day (once all the posturing had ended), she started participating and found that the atmosphere was just like that of groups with more women.
“Taking an animal behavior course was very useful,” she concluded. “As a result, I was less annoyed.”