Wednesday, December 30, 2009
Wednesday, December 16, 2009
This was the premise of a recent paper by Oliver Balmer and colleagues, studying trypanosome infection of mice hosts. They engineered two transgeneic strains of the protozoan parasite, Trypanosoma brucei (African sleeping sickness), to fluoresce different colors in order to assess infections. They infected mice with each strain separately and together and measured host survival and parasite density.
They found that when both strains were present, they competitively suppressed each other and that the level of suppression depended on the initial density of each strain. One of the strains was more virulent than the other, and infection by both strains reduced mortality by 15% compared to infection by the virulent strain only. This is due to the suppression of the virulent strain by the low virulent strain.
The authors argue that strain source and intraspecific genetic diversity can have an important effect on host mortality. I would also argue that understanding interspecific interactions and within-host niche differences, would also be critical.
What a cool use of molecular technology to test basic hypotheses about disease ecology.
Balmer, O., Stearns, S., Schötzau, A., & Brun, R. (2009). Intraspecific competition between co-infecting parasite strains enhances host survival in African trypanosomes Ecology, 90 (12), 3367-3378 DOI: 10.1890/08-2291.1
Thursday, November 26, 2009
These days, it seems like nearly everything in the supermarket is good for the environment in one way or another. Over the past decade, more and more companies have started using ecolabels to collect a premium on products that claim to contribute to environmental protection.
But not all ecolabels are created equal. The credibility of their claims varies widely, ranging from environmentally meaningful to downright exploitative.
A recent study by Adrian Treves and Stephanie Jones provides a model for policy-makers and consumers to discriminate between claims.
“In a nutshell, [we] were looking for a way to analyze this cloud of ecolabels out there, all of them claiming to be the best thing for a given species or the best thing for a given ecosystem,” said Treves in an interview.
In the early stages of their research, Treves and Jones realized that wildlife friendly ecolabels can be split along the same lines that have divided debating groups of conservationists. They drew upon these divergent perspectives to partition wildlife friendly ecolabels into three categories.
“Supportive” ecolabels such as Endangered Species Chocolate donate some percentage of revenues to conservation organizations. Verifying the claims for this category is compromised by the transfer of funds to a third-party recipient who is usually not accountable to consumers.
“Persuasive” ecolabels claim to improve production methods in a way that eliminates threats to wildlife, but do not assess actual conservation of wildlife. Although the persuasive category is more transparent and environmentally effective than the supportive one, this type of ecolabel bases its certification requirements on assumptions about threats to wildlife without testing how reduction of perceived threats impacts wildlife. Tuna labeled as Dolphin Safe is an example of a persuasive ecolabel.
“Protective” ecolabels certify wildlife conservation by assessing whether reduction of threats enhances wildlife populations. The Marine Stewardship Council certifies fisheries under a protective ecolabel. This category is the most meaningful to wildlife because it matches the recommendations of the latest conservation science. By following the scientific method, protective ecolabels can verify that they actually help humans and wildlife coexist.
Just as conservation is often pitted against economic interests like agriculture or development, ecolabels must balance a trade-off between consumer confidence and producer incentive.
Protective ecolabels gain the most consumer credibility but also require the greatest verification effort. Proving that producers conserved wildlife is costly, time-consuming, and logistically challenging. Wild animals habitually ignore property boundaries and can die or disperse for reasons unrelated to producer activities. Often, the costs associated with these challenges outweigh the economic incentive of being labeled as “green.”
Treves, A. and S. M. Jones. 2009. Strategic trade-offs for wildlife-friendly eco-labels. Frontiers in Ecology and the Environment. DOI:10.1890/080173
(Image courtesy of kateboydell at flickr under a Creative Commons license)
Wednesday, November 25, 2009
This study is the first field-based experiment of soil depth and coexistence, that I know of and the results are compelling. Plant species are segregating below-ground niches, and perhaps we look for other partitioning strategies for species that inhabit the same soil depth.
Dornbush, M., & Wilsey, B. (2009). Experimental manipulation of soil depth alters species richness and co-occurrence in restored tallgrass prairie Journal of Ecology DOI: 10.1111/j.1365-2745.2009.01605.x
Other notable recent papers on below-ground processes:
Bartelheimer, M., Gowing, D., & Silvertown, J. (2009). Explaining hydrological niches: the decisive role of below-ground competition in two closely related species Journal of Ecology DOI: 10.1111/j.1365-2745.2009.01598.x
Cramer, M., van Cauter, A., & Bond, W. (2009). Growth of N-fixing African savanna species is constrained by below-ground competition with grass Journal of Ecology DOI: 10.1111/j.1365-2745.2009.01594.x
Meier, C., Keyserling, K., & Bowman, W. (2009). Fine root inputs to soil reduce growth of a neighbouring plant via distinct mechanisms dependent on root carbon chemistry Journal of Ecology, 97 (5), 941-949 DOI: 10.1111/j.1365-2745.2009.01537.x
Sunday, November 22, 2009
Friday, November 20, 2009
"Differences in the information content of genomes led to the realization that, other things being equal, some organisms have intrinsically higher conservation worth than others." -Ross Crozier
Ross also recently was the handling editor, at Ecology Letters, on a paper of mine and his insights and support were greatly appreciated and helped to improve our manuscript in numerous ways.
Here are my two favorite papers of his.
Crozier, R. H. 1992. GENETIC DIVERSITY AND THE AGONY OF CHOICE. Biological Conservation 61:11-15.
Crozier, R. H. 1997. Preserving the information content of species: Genetic diversity, phylogeny, and conservation worth. Annual Review of Ecology and Systematics 28:243-268.
Thursday, November 19, 2009
In a combined study using field data and evidence of two experimental studies Eriksson et al. show that decline of top-predators and nutrient load have similar and additive effects on the abundance of ephemeral algae. Both factors together increased abundance of ephemeral algae many times! The field data revealed a strong negative correlation between the abundance of fish and ephemeral algae. When fish was depleted high abundances of their prey and at the same time high cover of ephemeral algae was observed. The experiments very nicely proofed these observations. By excluding predatory fish Eriksson et al. show that (i) the abundance of small mesopredators increased, (ii) the smaller gastropod grazers became smaller, and (iii) the net production of ephemeral algae increased. Moreover, the predator effect depended on grazers and habitat complexity. In the absence of grazers predator removal had no effect on algae growth. In the absence of canopy cover, i.e. a proxy for habitat complexity ephemeral algae growth doubled.
This paper makes a strong point that to successfully combat eutrophication the so far unidirectional view on either bottom-up or top-down forces should change towards an integrated approach taking into account both factors.
Britas Klemens Eriksson, Lars Ljunggren, Alfred Sandström, Gustav Johansson, Johanna Mattila, Anja Rubach, Sonja Råberg, Martin Snickars (2009) Declines in predatory fish promote bloom-forming macroalgae. Ecological Applications: Vol. 19, No. 8, pp. 1975-1988. doi: 10.1890/08-0964.1
Tuesday, November 17, 2009
The latest podcasts are fed into our blog roll on the right sidebar.
Monday, November 9, 2009
Washington State University ecologists, Renée Prasad and William Snyder convincingly show how behavioral responses to predation can fundamentally alter food web interactions and link previously independent predator-prey interactions. They used two spatially independent insect predator-prey links in a novel, factorially-designed experiment. The two food chains consisted of a ground-based one, where ground beetles consume fly eggs and a plant-based one, where green peach aphids feed on the plants and are consumed by lady beetles. Under the ground-based chain only, the ground-based chain plus aphids, or ground-based chain plus lady beetles, the ground beetles consume a high proportion of the fly eggs. However, when both aphids and lady beetles are present, aphids respond to lady beetles by dropping off the plants and the ground beetles switch from consuming fly eggs to aphids. Under this last treatment, very few fly eggs are consumed, fundamentally altering the strength of the linkages in the two food chains and connecting them together.
This research highlights the inherent complexity in trying to understand multispecies systems, where the actors potentially have behavioral responses to other species, changing the nature of interactions. These types of responses may also generally increase the connectedness of such networks, which may result in more stable food webs, but this would need to be empirically tested. Regardless, this type of experiment offers food-for-thought to scientists trying to work general processes into a broad understanding of food web dynamics.
Prasad, R., & Snyder, W. (2009). A non-trophic interaction chain links predators in different spatial niches Oecologia DOI: 10.1007/s00442-009-1486-7
Monday, November 2, 2009
At first glance, potato farms might seem like an unlikely candidate for conservation efforts.
But Wisconsin researchers are demonstrating that biodiversity can be restored even in the midst of large-scale farming.
Paul Zedler, professor of Environmental Studies at the University of Wisconsin (UW)-Madison, and his colleagues are working with potato farmers to restore pre-settlement habitats on growers’ lands.
In central Wisconsin, 42,600 acres are devoted to potatoes. Since the landscape is dominated by agriculture, some proportion of farmland must be set aside for conservation to preserve biodiversity in this part of the state.
Restoration is a requirement of the Wisconsin Healthy Grown potato program, a partnership between UW–Madison, the Wisconsin Potato and Vegetable Growers’ Association, and NGOs such as the International Crane Foundation, Defenders of Wildlife, and the World Wildlife Fund.
The groundwork for the Healthy Grown program was laid out in the 1980s, when a group of potato growers voluntarily discontinued use of the high-risk pesticide aldicarb. The farmers turned to UW-Madison researchers for pest-management advice. This grassroots movement eventually drew attention from conservation agencies.
To be certified under the Healthy Grown eco-label, potatoes must be grown under a set of standards that restrict pesticide and fertilizer use. The program was able to draw from an extensive body of UW-Madison research to guide the formulation of these in-field standards. But farmers and environmentalists were interested in doing more.
Since the program's conception, growers had expressed interest in managing their farms as whole ecosystems rather than just focusing on crop production on a field by field basis. At the same time, the NGOs saw the program as an opportunity to bring farmland into regional-scale conservation plans.
Satisfying this interest in developing a conservation standard for the eco-label was challenging for researchers because fewer precedents existed. Even the largest and most well-known eco-label, USDA Organic, does not include a conservation requirement in its certification standards.
Zedler and his colleagues looked to the Nature Conservancy, which had established a system for making strategic conservation decisions and measuring conservation success at sites where the objective is to improve biodiversity on whatever land can be spared from intensive human use.
Potato farms in central Wisconsin are unusual in their tendency to contain significant patches of marginal land without crops because these patches cannot be irrigated – a necessary factor in growing potatoes. The result is a complex mosaic of land in which remnant patches of disturbed natural habitat are isolated within an agricultural matrix. Zedler and his colleagues focused their research efforts on these patches of non-crop land.
Their research suggests that prescribed burns and control of invasive plant species can help restore disturbed non-crop land to the habitats that characterized central Wisconsin before European settlement: prairie, oak-pine savannah, and sedge meadow.
Thus far, the Healthy Grown program has restored more than 400 acres of privately owned farmland. According to Zedler and his colleagues, farmers’ strong ties to their land motivate their commitment to the conservation standard of the Healthy Grown eco-label.
Zedler, P. H., T. Anchor, D. Knuteson, C. Gratton, and J. Barzen. 2009. Using an ecolabel to promote on-farm conservation: the Wisconsin Healthy Grown experience. International Journal of Agricultural Sustainability 7(1): 61-74. DOI:10.3763/ijas.2009.0394
(Image courtesy of FotoosVanRobin at flickr under a Creative Commons license)
Thursday, October 29, 2009
- Writing/outlining research questions
- Taking courses
- Appointments with supervisor and committee
- Design/set-up experiments/studies
- Data collection
- Analyzing data
- Writing papers/chapters/articles
- Rewriting papers/chapters/articles
- Finding a publisher/lay out/submitting manuscripts
- Administrative duties
- The unexpected!
1 - Live by the calendar, die by the calendar. Basically, schedule everything. With freely available calendars like Google's or Sunbird there is no reason to not adopt a calendar. Web-based calendars, mean you can be anywhere, on any computer and still have access. Be sure to share the calendar with lab mates and professors, so they know when you are booked. Schedule everything from meetings, to large slots of time dedicated to time-intensive things like reviewing a manuscript or data analyses.
2- Gimme a break! Working for four straight hours without a break will cause you to be less productive, than four hours with a 5 minute break every 40-60 minutes. Don't be afraid to get up from your desk in between tasks to reset your brain. You could also call or chat with someone, make a coffee, watch a Daily Show clip, update your Facebook status, etc. Don't feel guilty about the 5 minute solitaire game (only about the 2 hour ones).
3- Leave. Have a secret work spot. It could the back corner of a library, a coffee shop, home, or some special place. The point is to have a productive site where you are not tempted to do nonproductive things when you need to be focusing on a task. Leave your e-mail behind if possible and do not let colleagues know where you are. Make it your time.
4- Delegate. You do not need to do everything yourself. If you are collaborating, don't be afraid to ask collaborators to do something. If you are at a big university, search for undergrad volunteers to help out. If you are really swamped, ask a friend to help out with an experiment.
5- Write it down or lose it. I write down everything, and I do it for two reasons. First, I will forget it if it is not written down in front of me (which saves me anxiety about forgetting things). Secondly, these notes become defacto to-do lists which saves me time from having to think about what to do next. If I have ten minutes before a meeting and my list has me e-mailing someone, then I get the reward of ticking something off the list.
6- Enough is enough. Remember, it will never be perfect. Likely, the 13th draft of paper is not appreciably better than the 12th. Plus, reviewers will ALWAYS recommend revisions and you will never win a literary award for it. So if you pour your soul into a manuscript and take 2 years to write it, likely you'll be devastated when you are asked for major revisions. The important thing is getting it submitted and learning when enough is enough can go a long way toward freeing up valuable time.
7- Have fun. Likely, you got into research because you love science. If your work is tedious and boring, find some fun research to offset it. If you have to choose between two projects, and one seems like it will be personally more enjoyable, go for that one. Don't be afraid to shelve a unrewarding project for one that is fun and exciting. Most importantly, reward your self! When you submit a paper, take the rest of the afternoon off. When you finish an intense summer of field work, go to the beach for four days. Tell your close colleagues when you get a paper accepted or an award -you are not bragging, and they will always say 'congrats' or 'awesome', which feels nice. Whatever works as a reward, use it.
Remember, at the end of the day what matters is getting papers out and being a good collaborator/student/mentor/human being. Control of priorities and successful time management will make it a lot easier to get those papers out and be a relaxed, good person to be around.
Monday, October 26, 2009
A colleague once said at a bar that she didn't believe in "conservation genetics". I'm not quite sure which aspect she was disputing, but one certain conflict is between gearing research toward conservation, while watching chemicals and consumables go into the waste stream. Most of the reactions in my lab are done using pipet tips and tubes made of virgin polypropylene. Nobody wants to recycle this stuff - even though 99% of the chemicals we use are fairly meek reagents like ethanol, water, nucleotides, and barnacle DNA, there's just no way to guarantee the waste stream coming from a building that does molecular research (e.g. you'd probably balk if that plastic got melted down and used for toys). Researchers have enough problems with reactions going wrong to also worry about whether their supplies are contaminated with the products of reactions past. Still, we have to constantly consider how we can minimize waste in the lab.
As a marine biologist, I'm also very conscious where all this plastic eventually ends up. I'm entertaining ideas for tip and tube recycling, though it is barely worth the effort for a single lab to do so: my lab probably consumes about 10kg of virgin polypropylene a year, into the trash. Super bummer. But that recycling effort could be balanced out if I just got my entire lab (including me) to stop drinking so much soda! Better would be to find institutional solutions, and we're a long way off on that.
Of course a lab is more than plastic. There are chemicals - which we've chosen to avoid some of the nastier ones, like ethidium bromide (using Ames-tested GelRed instead), isotopes (fluorescent-labeled primers), but still must use a little bit of polyacrylamide and a few other things in very small quantities that you wouldn't want to put in a smoothie. There are heating and cooling costs, which we can't do a lot about in our grumpy 1980's-era building at the University of Georgia (we'll assume that under budget constraints physical plant is doing what they can in that regard, though we did install some motion sensors on lights in the auxiliary rooms).
And then, there are all the gizmos. For the holidays I got a fun gift: a Kill-A-Watt. As procrastination during grant writing, I decided not only to check the energy consumption of things at home, but things in the lab. I don't know whether I believe paying to balance carbon emissions works (though at $3/month, I do it anyway), but it is interesting to know what the footprint of a lab like mine is. To make a long story short, it's mostly about the computers. Each computer in my lab used around 5kWh/day - up to $150 in annual energy bills, and actually the only things that compete with computers are my big chromatography fridge and my ultracold freezers (the -80° will use around 6000kWh/year!). Anyway, by unplugging some things that weren't being effectively used - one of the refrigerators, some water baths, an incubator, 2 of the computers - and ensuring that the rest were using the most appropriate power-saving settings - I cut the kWh consumption of my lab (only counting plug-in stuff) by over 10%.
The question is, how does this energy usage affect the science? One could argue that my research program hasn't expanded to fill the resources I had available, or that I can only cut back to the detriment of productivity. Only time will tell! We may have to devise a metric for productivity per kWh - but right now if I calculate my Hirsch index per kWh, it is not the thrilling kind of number I want to run to the administration with. I better get back to work.
Saturday, October 24, 2009
Wednesday, October 21, 2009
In a simple but elegant experiment, Jill Anderson and Monica Geber performed a reciprocal transplant experiment, moving Elliott's Blueberry plants between two habitats. One population was from highland, dryer habitats and the other from moist lowlands. They further evaluated performance in greenhouse conditions. Their results, published in Evolution, show that these two populations have not specialized to local conditions. Rather, due to asymmetric gene transfer, lowland individuals actually performed better when planted in highlands than compared to their home habitat. Further, in the greenhouse trials, lowland species did not perform better under higher moisture conditions. While genetic or physiological constraints may also limit adaptation, Anderson and Geber present a fairly convincing case that gene flow is the culprit.
These results reveal that populations may actually be relatively mal-adapted to local conditions, which has numerous consequences. For example, we need to be cognizant of adaptations to particular conditions when selecting populations for use in habitat restoration and when trying to predict response to altered climatic or land-use conditions. Importantly what does this mean for multi-species coexistence? Dispersal seems to limit the ability to adapt, and thus, better use local resources or maximize fitness, making for a better competitor. At the same time, dispersal can offset high death rates, allowing for the persistence of a population that would otherwise go extinct. Understanding how these two consequences of dispersal shape populations and communities is an interesting question, and work like Anderson and Geber's provides a foundation for future studies.
Anderson, J., & Geber, M. (2009). DEMOGRAPHIC SOURCE-SINK DYNAMICS RESTRICT LOCAL ADAPTATION IN ELLIOTT'S BLUEBERRY (
Evolution DOI: 10.1111/j.1558-5646.2009.00825.x
van der Heijden, M., & Horton, T. (2009). Socialism in soil? The importance of mycorrhizal fungal networks for facilitation in natural ecosystems Journal of Ecology, 97 (6), 1139-1150 DOI: 10.1111/j.1365-2745.2009.01570.x
Saturday, October 17, 2009
However, not all researchers have completely embraced OA journals. There are two commonly articulated concerns. The first is that many OA journals are not indexed, in most notably Thomson Reuters Web of Knowledge, meaning that a paper will not show up in topic searches, nor will citations be tracked. I for one do not like the idea of a company determining which journals deserve inclusion, thus affecting our choice of journals to submit to.
The second concern is that some OA journals are expensive to publish in. This is especially true for the more prestigious OA journals. Even though such OA journals often provide cash-strapped authors the ability to request a cost deferment, the perception is that you generally need to allocate significant funds for publishing in OA journals. While this cost may be justifiable to an author for inclusion in a journal like PLoS Biology, because of the level of readership and visibility. However, there are other, new, profit-driven journals, which see the OA model as a good business model, with little overhead and the opportunity to charge $1000-2000 per article.
I think that, with the rise of Google Scholar, and tools to assess impact factors (e.g., Publish or Perish), assessing difference sources for articles is available. The second concern is a little more serious, and a broad-scale solution is not readily apparent.
Number of Open Access journals
Regardless, OA journals have proliferated in the past decade. Using the directory of biology OA journals, I show above that the majority of OA journals have appeared after 2000. Some of these have not been successful having faltered after a few volumes, such as the World Wide Web Journal of Biology which published nine volumes with the last in 2004. I am fairly confident that not all these journals could possibly be successful, but I hope that enough are. By having real OA options, especially higher-profile journals, research and academia benefit as a whole.
Which journals become higher profile and viewed as an attractive place to submit a paper is a complex process depending on a strong and dedicated editorial staff and emergent property of the articles submitted. I hope that researchers out there really consider OA journals as a venue for some of their papers and become part of the 'win-win' equation.
Wednesday, October 14, 2009
However, in the interviews with these great scientists, there was a common thread in what they said. They reiterated the need to support basic science and that the pursuit of curiosity-driven science is a worthy and valuable enterprise. I found the fact that they found it necessary to reiterate this to be interesting and something that interviewers thought worthy of reiterating themselves. I know that news stories need to relate to a person’s everyday experience, but, I think, basic science offers something more. To quote Darwin “There is grandeur in this view of life”. That is, while the products of science have surely improved our quality of live, science has given us something deeper and more meaningful. Basic curiosity-driven research has changed our understanding of the world and our place in it. We now look up at the stars and have a pretty good idea of what they are. We know what causes thunder and lightening. We understand why our pet cat looks kinda of like a lion and gorillas like people. We no longer look to superstition and myth to explain these aspects of nature. To me, this is the fundamental contribution of science to humanity, and I wish this were as celebrated as technological advances. Though being able to take 2 gigabytes of photos and movies when my daughter is doing something cute is pretty cool too, I guess.
Friday, October 9, 2009
Science in a web-base universe now has the potential to link vast numbers of researchers together and be communicated to the global citizenry. Exploring the power of the web in science is the fourth annual Science Online 2010 conference, which will be held from Jan. 14-17 in the Research Triangle Park, NC. The conference is free, but of course you still must pay for travel and housing. Unless of course you've written an outstanding evolution blog post! NESCENT, the National Evolutionary Synthesis Center, is offering two $750 awards for the best evolution blog post about an evolutionary-oriented paper published in 2009.
For more details see the Deep-Sea News post. Be sure to tell your blogger friends!
Wednesday, October 7, 2009
They studied invaded plant communities across Europe, observing pollinator visits to flowers in multiple 50 x 50 m plots. They calculated connectance as the number of interactions standardized by network size. They showed that exotics fully integrated into plant-pollinator networks. Exotic species accounted for 42% of all pollinator visits and 24% of all network connections -a testament to the overall abundance of exotics in many communities. However, these exotics did not affect overall changes in network connectedness, revealing that these networks are quite robust to invasions.
That said, researchers must now ask if this is true in networks that do contain high numbers of specialists (e.g., orchids) or if the relative few specialists in generalist-dominated systems are more susceptible to changes from exotics.
Vila, M., Bartomeus, I., Dietzsch, A., Petanidou, T., Steffan-Dewenter, I., Stout, J., & Tscheulin, T. (2009). Invasive plant integration into native plant-pollinator networks across Europe Proceedings of the Royal Society B: Biological Sciences, 276 (1674), 3887-3893 DOI: 10.1098/rspb.2009.1076
Friday, October 2, 2009
The simplest way to do this is to make sure you have a Google account and use their Google reader. If you go to a journal's website you click on either of these symbols:
You'll be sent to their RSS feed page and at the top is a subscription option and you can select Google to subscribe using:
When you click on 'Subscribe Now', it prompts you to select the Google homepage or reader -I use reader, but that just depends on your preference. You can subscribe to as many Journals as you want, and I think that all the major ones have RSS set up. Then to keep up on recently published papers, you simply go to your Google reader and scroll through the journals you have RSS subscriptions. Or if you check it more often, the reader keeps a list of the most recent items from all your subscriptions. No more getting e-mail alerts and no more going to a bunch of different journal pages.
By the way, you can also subscribe to this blog in the same way (see 'subscribe to' links on side panel).
Friday, September 25, 2009
O'Connor and colleagues experimentally warmed marine microcosms and tested two alternative hypotheses on food web structure: 1) that productivity increases with warming; and 2) warming increases metabolic rates, thus changing consumer-autotroph (i.e., primary producers) interactions. What they found was that warming indeed altered consumer-autotroph interactions. Warming increased base metabolic rates of consumers, as well as primary production, and the net effect was that food webs shifted towards increasing consumer control (i.e., top-down control).
What this research means is that global warming may alter food web interactions by increasing resource needs of organisms as their metabolic rates increase. This may increase the stress on communities and change diversity patterns as increased needs may shift competitive hierarchies or affect autotroph's ability to withstand consumer effects.
O'Connor, M., Piehler, M., Leech, D., Anton, A., & Bruno, J. (2009). Warming and Resource Availability Shift Food Web Structure and Metabolism PLoS Biology, 7 (8) DOI: 10.1371/journal.pbio.1000178
Monday, September 21, 2009
In a forthcoming paper from Heinke Jäger and colleagues in the Journal of Ecology, Cinchona pubescens invasions on the Galápagos Islands were monitored in long-term plots for more than seven years. What they found was that there was a four-fold increase in Cinchona density as the invasion progressed and that this increase had measurable effects on native species abundance. While they did not observe any native extirpations in their plots, native densities decreased by at least 50%. Of the greatest concern was that Island endemics appear to the most susceptible to this invasion.
What these results show is that, while there were not any observed extinctions, there were serious deleterious changes to native diversity. Further, the native species, and especially the endemics, are now more susceptible to other invasions or disturbances due to their lower abundances. The impact of exotic invaders may not be readily apparent but may be a major contributor to increased extinction risk.
Jäger, H., Kowarik, I., & Tye, A. (2009). Destruction without extinction: long-term impacts of an invasive tree species on Galápagos highland vegetation Journal of Ecology DOI: 10.1111/j.1365-2745.2009.01578.x
Wednesday, September 9, 2009
- Ian Wright gave an interesting talk about the history of functional plant ecology. Basically, covering where trait ecology has been and where we are now. It is really amazing to see the truly large scale analysis and collaborations currently driving modern trait analysis.
- In another overview type talk, Gerlinde De Deyn, talked about carbon sequestration in soils. I'm sure to many ecosystem ecologists this maybe well known, but I found it fascinating. Did you know that tundra ecosystem have as much soil carbon as tropical rain forests? The reason is that tundra has very slow process rates (cold) while rain forests have fast production rates. In fertilization experiments, soil carbon is reduced, so in order to manipulate soil carbon stores one must understand the interaction between plant traits and soil organisms.
- Finally, Kyle Dexter, in a great field survey of Inga tree species in a region of Peru, showed that different functional diversity metrics show differing patterns of over- and under-dispersion. For example, phylogenetic diversity tends to be under-dispersed for Inga assemblages, while chemical and anti-herbivory traits are over dispersed and leaf size measures are under-dispersed.
Also, there was the annual general meeting, which was rather somber as three obituaries were read aloud. The three deceased, John Harper, Bob Jefferies and Simon Thirgood, were all superb ecologists who absences were obviously felt. Harper (my Master's advisor's advisor) and Jefferies (my colleague at Toronto) were both eminent ecologists with long and distinguished careers, while Thirgood (a fellow Senior Editor at the Journal of Applied Ecology) was in the prime of his very successful career.
I think that ecologists are often wary of GMOs and his talk was a convincing case for their use in basic research, and he advocated for a more reasoned approach to their use.
*Note: He has run into trouble with German authorities over using the title 'Dr.' -see here.
Monday, September 7, 2009
Check back for more.
Wednesday, September 2, 2009
I for one have been (overly) optimistic and really didn't buy the hype that the job market would crash this year and for the foreseeable future. I think that many institutions over-reacted to the recession. Of course some states, like California, are in absolute dire straights. But my feeling is that over the next couple of years many institutions will try to recover from their self-imposed professor deficits, meaning that many similar-sounding job searches will be active at the same time. The net result is that schools will be competing against one another for good researchers.
Tuesday, August 25, 2009
In a new publication in PNAS by Wood et al. -from the Loren Rieseberg lab (one of the best lab homepages BTW) this questions has been answered. The authors go through all available chromosome counts on the Missouri Botanical Garden's Index to Plant Chromosome Numbers, and assess the proportion of polyploid species. They find that about 15% of all angiosperm speciation events coincided with an increase in chromosome number (and about 30% of fern species). Further, about 35% of all genera contain polyploids. Looking across the phylogeny of major plant groups, they find that all major lineages, except Gymnosperms, have significant proportions of polyploids (again with ferns have the greatest proportion). Polyploidy is a ubiquitous feature of plant diversity and a major driver of plant speciation. And now we can quantify just how important.
Wood, T., Takebayashi, N., Barker, M., Mayrose, I., Greenspoon, P., & Rieseberg, L. (2009). The frequency of polyploid speciation in vascular plants Proceedings of the National Academy of Sciences, 106 (33), 13875-13879 DOI: 10.1073/pnas.0811575106
Tuesday, August 18, 2009
In a new paper in the Journal of Ecology, Andrew MacDougall, Benjamin Gilbert and Jonathan Levin use Peter Chesson's framework where ability for two species to coexistence (or conversely the strength of competitive exclusion) is a process relative to two factors -the magnitude of fitness differences and the degree of resource use overlap. Here competitive exclusion is rapid if species have a large fitness difference and high resource overlap, and slow if fitness differences are low. Species that are successful because of reduced resource overlap likely have little impact unless there are large fitness inequalities.
If we then view the invasions process on a continuum (see figure), then by determining basic fitness and resource use, we can predict success and impact. This is an exciting development and I hope it inspires a new generation of experiments.
MacDougall, A., Gilbert, B., & Levine, J. (2009). Plant invasions and the niche Journal of Ecology, 97 (4), 609-615 DOI: 10.1111/j.1365-2745.2009.01514.x
Thursday, August 6, 2009
Back to my real life tomorrow!
Wednesday, August 5, 2009
I am looking forward to more great talks!