Fall colors redux

For those of us in temperate deciduous regions, now is the time of landscapes splashed in red, orange and gold. Here is a link to a post I wrote back in March about the evolutionary meaning of autumn colors. It seemed appropriate to dig it up.

Adaptation and dispersal = (mal)adapted

Ever since Darwin, we often think of organisms as being in a constant battle against other organisms and local environments. Thus natural selection and the resulting arms race results in organisms highly adapted to local conditions and against local antagonists. At the same time, and especially driven by theoretical advances in the 1990's, researchers began to ask how dispersal -that is, the flow of genetic material from elsewhere, can disrupt local adaptation. On the one hand it may provide genetic variation allowing for novel solutions to new difficulties. On the other hand, dispersal may reduce the prevalence of fitness-increasing genes within local populations.

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 (

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Evolution DOI: 10.1111/j.1558-5646.2009.00825.x

Mycorrhizal Networks: Socialists, capitalists or superorganisms?

Mycorrhizal networks – fungal mycelium that colonize and connect roots of one or more plant species – are a very intriguing type of fungal-plant association. There is evidence of substantial facilitation between plant individuals via these fungal networks. This can have drastic implications for our understanding of nature, given that the common perception is that other mechanisms, like competition, herbivory or dispersal, are the main drivers of plant community associations. This may be far from reality if the existence of “socialist” networks is widespread (e.g. the ability to connect and profit from a network may be more important than competitive abilities). In the last issue of the Journal of Ecology ( that has a very interesting special feature on facilitation in plant communities), Marcel Van der Heijden and Tom Horton conducted a review of the topic. They found a general positive effect of mycorrhizal networks on seedlings and large plants (i.e. plants tend to grow better if they are associated with a network). However, the reviewers also found some networks can have a neutral or even a negative effect on plants. The plant responses were highly variable depending on other variables including fungal species, nutrients availability, and plant identity. The positive effect of some fungal networks on seedlings growing nearby adult trees of its same species is somehow opposite to the predictions of the Janzen-Connell hypothesis. We need further studies to understand the overall importance of mycorrhizal networks in relation to other better understood mechanisms.

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

The making of an open era

With the availability of open access (OA) journals, academics now have a choice to make when deciding where to send their manuscripts. The idealistic version of OA journals represents a 'win-win' for researchers. The researchers publishing their work ensure the widest possible audience and research has shown a citation advantage for OA papers. The other side of the 'win-win' scenario is that researchers, no matter where they are, or how rich their institution, get immediate access to high-caliber research papers.

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.

The Nobel prize and the grandeur view of life

As news of the latest Nobel prizes in physics and medicine were announced, science became a central story for many news outlets. Numerous stories and interviews were held about the discoveries that earned the laureates their just rewards. I’ve heard interviews with medicine winners, Elizabeth Blackburn and Carol Greider (2/3 of the prize, the other being Jack Szostak), about their discovery of telomeres and telomerase, and with Willard Boyle (for physics) on inventing an imaging semiconductor circuit (i.e., digital recording of light). The media play up the applications to humanity. Telomeres and telomerase offer a deeper understanding of cancer and potential treatments. The digital recording of light gave us digital cameras (among a plethora of other technologies).

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.

Blog your way to North Carolina!

(sorry for reiterating what you may have already seen)

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!

Exotic plants integrate into plant-pollinator networks

At almost any spot on the globe, there are species present that are not native to that locale, having been transported by human activities. Whether and how exotic species impact communities is a multifaceted problem that requires understanding the multitude of direct and indirect species interactions that occur. In a paper published in the Proceedings of the Royal Society, B, Montserrat Vila and colleagues asked if exotic plants where integrated into plant-pollinator networks, and whether this integration had any observable impacts on these networks. This is an important question, as most ecological theory predicts that plant-pollinator networks are actually quite resilient to perturbations since most associations tend to be between generalists as opposed to the more susceptible specialists.

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

How to keep up on your favorite journals

Researchers live busy lives. Either you are spending your waking hours writing grant proposals, running experiments, analyzing data, writing papers, preparing lectures, supervising students, attending committee meetings, and not to mention taking care of your personal life. Often the activity that slips to the bottom of this list is keeping up on the current literature. How should one go about maximizing their ability to efficiently peruse recent publications. I think the best approach is to use journals RSS feeds (otherwise known as Really Simple Syndication). RSS is a web format that allows publishers to syndicate the abstracts of papers as they are published online.

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:

or

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).

Global warming and shifts in food web strucutre

Predicting the effects of global warming on biological systems is of critical importance for informing proactive policy decisions. Most research so far has been on trying to predict shifts in species distributions and changes in interactions within local habitats. But what many of these studies assume is that the basic biological processes and requirements of the individual species will not change -that is their biology is fixed and they simply need to find the place that best suits them. Not so, say Mary O'Connor and colleagues, in a just-released study in PLoS Biology.

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

Everything but extinct: invasion impacts on native diversity

There has been a persistent debate in the plant invasions literature about whether exotic plant invasions are a major threat to native plant persistence. While there are clear examples of animal invasions resulting in large scale extinction -e.g., the brown tree snake or Nile perch, evidence has been ambiguous for plants. Most ecologists are not so sanguine as to actually conclude that plant invasions are not a threat, and I think most believe that plant invader effects are an issue of temporal and spatial scale and that the worst is yet to come.

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