Morgan’s Favorite Portal Species

As part of our Portal 40^th anniversary celebration, some of us will contribute our thoughts on our favorite species at Portal. We’ve already had several posts on the Banner-tailed Kangaroo Rat (a universally beloved species at the site). But, I have a confession, while I love Banner-tails, they are not my favorite species at Portal (cue collective gasp). No, my favorite species is the grasshopper mouse. We have two species of grasshopper mice at Portal, the Northern and the Southern Grasshopper Mouse (Onychomys leucogaster and Onychomys torridus).

Northern Grasshopper mouse. Wikimedia Commons, Public Domain

Southern Grasshopper Mouse. Wikimedia Commons. Public Domain

They are similar in their biology and morphology. Both are small (usually less than 6 inches or 120-163 mm in length including the tail) and weigh less than 40 grams (or 0.088 lbs). Given their similarities, I like them equally well, so will simply refer to grasshopper mice generically for our purposes today.

Anyone who has interacted with a grasshopper mouse probably remembers the encounter. Grasshopper mice have sharp little teeth and love to use them. Keeping an eye on the front end wouldn’t be that hard if you didn’t also have to also keep a sharp eye on the back end. The teeth are just a distraction from the fact they are trying to coat you  with liquidy, yellowish diarrhea. Oh, and did I mention that grasshopper mice REEK. Yes, I do mean reek. Their oily, acrid scent curdles the nose hairs and lingers after the little rodent is gone (probably because they managed to smear some poo on you in retribution before they headed off).

So right about know, you’re probably wondering why this reeking, vicious little rodent is my favorite species at Portal (or you’re wondering what this says about my personality).  With so many amazing rodents to choose from at Portal, what makes the grasshopper mouse so special? The reason grasshopper mice are notably more aggressive than our other species is that grasshopper mice are predators – yes, predators. They will eat seeds when resources get scarce and cache seeds in their burrows (Ruffer 1965), but they actively hunt insects, small rodents, arthropods, and even reptiles. They even hunt scorpions – see for yourself. The video below shows in sequence an adult, a subadult, and a juvenile attacking a scorpion. The adult knows to chew off the stinger quickly. The younger ones….well, it’s definitely a more difficult experience for them, though they eventually get their meal.

Why can these mice withstand scorpion stings? Without getting into sodium ion channel-level detail , basically they have a special protein that binds to the scorpion’s neurotoxin that changes how it works (Rowe and Rowe 2008)– as a result not only doesn’t the sting hurt, it actually ends up numbing the area of the sting (Rowe et al 2013).

Grasshopper mice also have surprising social relationships. There are a variety of reports that male and female grasshopper mice form strong pair-bonds and that both sexes participate equally in offspring care (McCarty and Southwick, 1977) and make the nest burrows together (Ruffer 1965). Grasshopper mice have a calling behavior using sounds that are almost ultra-sonic (Hafner and Hafner 1979). Though members of a family group have similar calls, every individual has unique call characteristics, which means that Grasshopper mice may be able to use these calls to communicate with family members over long distances (Hafner and Hafner 1979). When they call, they stand on their hind legs and throw their heads back:

Some mammalogists cannot see past the reeking, bitty little animal with the magical stinking poo that seems to get on you no matter how hard you try to avoid it. But when I see a grasshopper mouse, I see a little mouse who thinks it’s a coyote. I see some cool evolution at play that takes a normal mouse and turns it into a scorpion-resistant killing machine. I also see a brave little mouse fearlessly taking on a scary world. There’s something about it that just makes me smile. And then I go get some hand sanitizer.

 

Scientific Studies Cited in this Post:

Hafner, M.S., and D.J. Hafner. 1979. Vocalizations of Grasshopper Mice (Genus Onychomys). Journal of Mammalogy 60:85-94

McCarty, R., and C. H. Southwick. 1977. Patterns of parental care in two cricetid rodents, Onychomys torridus and Peromyscus leucopus. Animal Behaviour 25:945–948.

Rowe, A. H., and M. P. Rowe. 2008. Physiological resistance of grasshopper mice (Onychomys spp.) to Arizona bark scorpion (Centruroides exilicauda) venom. Toxicon 52:597–605.

Rowe, A. H., Y. Xiao, M. P. Rowe, T. R. Cummins, and H. H. Zakon. 2013. Voltage-Gated Sodium Channel in Grasshopper Mice Defends Against Bark Scorpion Toxin. Science 342:441–446.

Ruffer, D. G. 1965. Burrows and Burrowing Behavior of Onychomys leucogaster. Journal of Mammalogy 46:241–247.

 

 

How do people use the Portal Data?

Every so often, someone asks me for a Portal reading list to come up to speed on what we know about the site. This seems like a simple questions, but it is actually pretty difficult. We define a “Portal Paper” as a paper using data collected at the study site (whether or not Portal Project people were involved), or data collected near the study site if that data was collected by the project or with substantive assistance from our project. Over the years, the site has contributed to over 120 papers and book chapters (our current estimate is 123, but we still find older papers that we didn’t know existed).

How the Portal Data is used has been changing in recent years. Historically, most papers were by people affiliated with the group. As we’ve blogged about before, starting in 2009 we have been working on making our data openly available through  number of venues. We post all of our data on the Portal GitHub Repo and we have also published two Data Papers through Ecology’s Ecological Archives. The nice thing about Data Papers is that they are indexed and cited just like regular scholarly papers, which is important because it allows us to 1)  document that the Portal Project is a valuable scientific resource to the community (which theoretically may be helpful on grant applications) and 2) let us here at the Portal Project keep informed of results coming out of the site that we’re not involved in.  So, how are scientists, external to our group, using our openly available data? Google Scholar lists 22 citations between the 2 data papers. (For the non-academics, citing other papers is in our own papers is an important part of scientific publishing. It allows us to give credit to those whose ideas, data, or methods we are working with. It also allows to us provide proof or support that statements we make in our papers are supported by things other people have been finding. Google Scholar is a database that keeps track of these citations). Here’s the breakdown of what Google Scholar says has been citing our Data Papers:

All the site focused research (papers that use our data as the primary focus of their analysis) was done by  or in collaboration with someone affiliated with the project. If other researchers are using our data, so far they tend to either use it as part of a meta-analysis (i.e. as one of many data points in the analysis) or to make a figure for their statistical or conceptual paper that has an empirical example of what they are talking about. (Three papers cite a Data Paper for reasons that defy classification. After reading their paper I have no idea why they cited us)! This number of citations listed by Google Scholar is probably a little lower than the database’s actual use in papers because data citations for meta-analyses often get shoved off into the supplementary materials and are not indexed by Google Scholar as a result. Our usage in meta-analyses is probably higher, but it is unlikely that we’ve missed a paper focused solely on data from our site.

We are hoping to increase Portal’s usability and we have some things in the works, which we will blog about later, that we hope will make it easier for people to get the data they need to use Portal as part of their analyses. We love seeing the data used but know that the history of the site and all the manipulation changes can make it difficult to figure out how to extract the data you need.

 

Portal Plant Census and Florida Hurricanes

Twice each year we head out to the site to do an intensive week of field work. We catch rodents as we do every month, but we also count every plant located in the 384 different plant quadrats, located across the site (for those who want more details: 16 quadrats per plot, locations marked with rebar, each 0.25 m^2 in size). Plants have been counted on these quadrats for nearly 40 years and we have been keeping the tradition alive. These extended trips occur sometime in August/September and March/April to match up with when most plants during that season are flowering or setting seeds (or as best we can given the constraints of the school year). Since the lab moved to Florida, the August/September census has gained an added piece of excitement: hurricanes.

Hurricanes?

Yes. Hurricanes.

Last year, as the crew was preparing to set out for Arizona, Hurricane Hermine  was lining up to hit Florida. Being the lab’s first hurricane experience (and the first hurricane to hit Florida since 2005), there was a lot of anxiety as the crew packed up to head out. Would they get out ahead of the storm? What would happen while they were gone?

The storm was an exciting experience for those of us who remained in Gainesville (in the ‘uh, wow, look at all those trees down’ way, not the ‘Whoo, let’s do that again’ way). Hurricane Hermine skirted Gainesville, delivering strong winds, rain, and some downed trees.

Image from Wikimedia Commons. Image uses background image from NASA and hurricane tracking data from NOAA. The yellowish color were it hits land indicates it was a Category 1 at landfall. The star is the approximate location of the University of Florida

Though the Portal crew was out in Arizona, they did not escape without their own hurricane experience, though! Hurricane Newton hit Baja California and then came up to the Portal area for a visit.

Image from Wikimedia Commons. Image uses background image from NASA and hurricane tracking data from NOAA. The star is the approximate location of the Portal Project. The blue triangle indicates that Newton was a tropical depression by the time it got close to the site.

Despite my anxiety for the crew, they just got really wet.

Ellen and Joan enjoying a tropical storm in the desert

We laughed about it and then forgot about all this until a couple of weeks ago when Hurricane Irma lined up on Florida as the Portal Plant Crew was preparing to head out to Arizona to count plants.

Hurricane Irma track. Gainesville was luckier than other places that received visits from Irma. It was only a tropical storm when it came by. Image from NASA, track data from NOAA, obtained from Wikimedia Commons

Shawn Taylor, one of Ethan White’s graduate students and regular Portal Plant counter, remarked on his déjà vu feeling in a message to the lab:

“Interestingly this is exactly how leaving for the fall plant census was last year as Hurricane Hermine was bearing down”

Now, any good scientist knows that correlation does not mean causation. Our sample size is also very small, with only two incidences so far. I’ll just say that it’s an interesting coincidence that Florida gets hit with hurricanes when the Portal Plant crew heads to Arizona in September. No one should contact FEMA to have “keep the Portal plant crew in Florida” added to their disaster preparation list. But at the very least, we probably need to add some “in case of hurricane” items to our summer plant census check list for next year!

How fast can a desert turn green?

In the desert, water is life. Without it, the desert is brown and dusty. At our site, the rains come twice a year – once during the ‘winter’ (I put that in quotes for our readers where winter means snow and/or extended periods below freezing) and once during the summer. Water in the summer and water in the winter don’t have the same effect on the desert, though. Plants need both warmth and water to grow. When rain falls in the desert in the winter, growth is slow and typically waits until the warmer temperatures of spring. In the summer, though, the high temperatures and the rain from Arizona’s monsoons make for an explosive combination. How fast can the desert turn green? Here’s a series of photos from our site – one per day for a week that we think conveys this better than words. Enjoy the slide show:

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You might be wondering if that was it. Was that as green as the desert got? Here it is, as of yesterday, 3 and a half weeks after that first brown picture: August 1^st was definitely not peak green:

The grasses are greening up nicely and there is no bareground to be seen in the foreground.Water, heat, and sunshine – a very powerful combo indeed!

 

 

Portal at the Ecological Society of America Meeting

Every year ecologists from across the U.S. descend upon a city to share their most recent findings with each other at the Ecological Society of America’s annual meeting. Normally, the locals are a little befuddled by the sudden influx of people wearing Tevas and Chacos and wearing clothing from various outdoor gear companies, but this year the meeting is being held in Portland, Oregon!

This year there are several presentations featuring data from the Portal Project, ranging from a poster to talks to a workshop. If you are going to be at the meeting and are interested in hearing about the site, learning more about the data, or taking a Data Carpentry that uses a teaching version of our data, check out the events listed below. These are just the things we happen to know about. If your talk uses data from Portal (either focused on the site or as part of a bigger meta-analysis / macroecological study), let us know in the comments and we’ll add you to the list!

Saturday, August 5th

8:00 AM-5:00 PM A105, Oregon Convention Center

Data Carpentry in Ecology Workshop

Organizers: Monica Granados, University of Guelph and Auriel M.V. Fournier, University of Arkansas – Fayetteville

(Paraphrased from the Meeting Program) This workshop uses a tabular ecology dataset from the Portal Project Teaching Database and teaches data cleaning, management, analysis and visualization. We use a single dataset throughout the workshop to model the data management and analysis workflow that a researcher would use.

Monday, August 7th

02:50 PM – 03:10 PM Oregon Convention Center – C120-121:

Novel approach for the analysis of community dynamics: Separating rapid reorganizations from gradual trends by Erica Christensen, S.K. Morgan Ernest and David J. Harris, Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, University of Florida.

03:20 PM – 03:40 PM Oregon Convention Center – C120-121:

Do existing communities slow community reorganization in response to changes in assembly processes? by Erica Christensen and S.K. Morgan Ernest, Wildlife Ecology and Conservation, University of Florida, Gainesville, FL

Thursday, August 10th

04:30 PM – 06:30 PM Oregon Convention Center – Exhibit Hall

DNA metabarcoding of fecal samples provides insight into desert rodent diet partitioning by Ellen K. Bledsoe, Samantha M. Wisely and S.K. Morgan Ernest, Wildlife Ecology and Conservation, University of Florida, Gainesville, FL

Friday, August 11^th

8:00 am-08:30 am Oregon Convention Center, Portland Ballroom 257

Advancing biodiversity-ecosystem function research by integrating community assembly: The CAFE approach by Katherine Bannar-Martin, Fisheries and Oceans Canada, Colin T. Kremer, Yale University, S.K. Morgan Ernest, University of Florida, Mathew A. Leibold, University of Texas at Austin, sCAFE working group, iDiv

Hope to see you there!

The Portal Project 40th Anniversary

Funded by the National Science Foundation to study the importance of competition and granivory in desert ecosystems, the Portal Project first started collecting data in the summer of 1977. The initial grant was just for 5 years, yet 40 years later the site is still collecting data on plants, rodents, and weather.

To our friends who study paleoecology, 40 years is an eyeblink but in the span of a human life, 40 years is a long time. As you might expect, much has changed on the project. For one thing, after 40 years, the team running the site has changed. The original team of scientists, Jim Brown, Dinah Davidson, and Jim Reichman have all retired from the daily challenges of training students and writing grants, though some are still doing science. In their place, Tom Valone and I do our best to keep things running, studying the mysteries of the desert, and training the next generation of scientists who will hopefully take our place.

But more than just the people have changed. The site has changed too. It was easier to gaze across the site back then, before the Acacia went wild and started to take over.

Left: Jim Brown in the late 1970s at the site (unknown photographer) Right: View from the ramada towards plot 1 (photo by Erica Christensen). Not a paired photo, but you get the idea.

The invasive plant, Erodium cicutarium, was a lot rarer back then

You can call Erodium cicutarium, redstem filaree, redstem stork’s bill, or common stork’s bill, but our rodents call it yummy.  Photo by Sarah Supp.

And Banner-tailed kangaroo rats (and their distinctive mounds) were abundant.

The distinctive cleared off mound of a Banner-tailed Kangaroo rat. Typically only one individual lives in a mound (unless the kids are still living in mom’s basement). Photo by Sarah Supp.

Our weather data is now recorded by an automated weather station that sends us the data via cellular signals, as opposed to laboriously transcribed from a contraption that would boggle the minds of younger ecologists!

Left: We don’t have any images of the original weather station, but we do have what it produced: large round sheets of paper with squiggles. Right: the new hotness in weather stations. A post about this bad boy will be coming in the future. The previous automated weather station, which is still running as we trouble shoot the new one, is to the left in the image.

But for all the things that have changed, there are many things that remain the same. We still collect data at the same plots at the same stakes using the same methods.

We still use quadrats to count the plants – though quadrat size was decreased to its current state back in the 1980s. Photo by Erica Christensen

The only change to the rodent processing has been the addition of PIT tags and we now process rodents at a central location on their plot. In the early years the number of rodents was lower and processing while picking up traps was common, but this is slow when numbers are high. Photo by Ryan O’Donnell

The site is still intellectually powered by motivated and creative young scientists who are inspired by the place and the data it generates

 

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We still collect data with paper and pencil (though we are debating moving to digital technologies there as well)

The mountains are still stunning

Photo by Glenda Yenni

And, most importantly, the Ramada is still where we gather to share stories, plan the day’s fieldwork, and commiserate over the inevitable challenges of doing fieldwork in a remote, challenging, but amazing location.

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To celebrate Portal’s 40^th Anniversary, we plan on having a blog a week for the next year (that’s our goal anyway!). These blog posts will focus on the science, the natural history, and the people who have helped make this one of the world’s longest running community ecology experiments.

We have reached out to many of the graduate students and postdocs who have worked at the site over the years asking for memories and stories, but we have not been able to find all of you. If you have a story about Portal or pictures from the site (especially from the early years!) that you’d like to share, let us know in the comments! We have 51 more weeks to fill!

The Banner-tailed Kangaroo Rat: The Once – but probably not future – King

In 1977 when Jim Brown, Diane Davidson, and Jim Reichman started the Portal Project, the site looked like this:

Photo of Portal Project from around 1977 (we think).

 

This desert heaven was home to a variety of small mammals. One of the most abundant of these was the Banner-tailed Kangaroo Rat. While I feel that most small mammals are adorable (*cough* *cough* Packrat), the Banner-tail is the one that is universally beloved by generations of Portal researchers.

 

Banner-tailed Kangaroo Rat (Dipodomys spectabilis). How can we tell? Note its size relative to the hand and the white tuft at the end of the tail.

Kangaroo rats in general are lovely creatures. As their name suggests, these nocturnal rodents hop around like kangaroos on enlarged backlegs. As least one scientist has seen a kangaroo rat use those strong back legs to leap 5 feet horizontally (with a two foot ground clearance)¹. They have a long tail which may play a role in locomotion¹ and fur-lined cheek pouches that they use like a bag to carry around seeds they gather from the environment. Most kangaroo rats eat primarily seeds. A study in Nevada found that Merriam’s Kangaroo Rat (a species we have at Portal) has a diet of  approximately 70-100% seeds (it varies over the year) and they eat a small number of insects as well.² Anyway, you get the idea, kangaroo rats in general are cool. Most kangaroo rats – like Merriam’s – are about 40-70 grams (that’s about 0.09-0.15 pounds). But there are a few kangaroo rats that are notably larger. The Banner-tailed Kangaroo Rat is one of these, being closer to ¼ of a pound.

 

So, in 1977 three kangaroo rats, alike in dignity in fair Portal where we lay our scene, coexisted without evidence of ancient grudge or new mutiny⁴: Banner-tails (Dipodomys spectabilis), Merriam’s (Dipodomys merriami) and Ord’s (Dipodomys ordii).

The plot below shows the population dynamics of the three kangaroo rats. The plot goes from 1977 to 2014⁵ and shows the population size in energy use⁶. I like energy use – especially when I’m dealing with Banner-tails – because large animals need more food than small animals. So one large banner-tail needs the equivalent amount of energy as 2¾ Merriam’s (based on their metabolic rates). By converting the population numbers to energy use, it helps correct for this difference in food consumption. So, the graph shows that early on in the study, Banner-tails were energetically more dominant than Merriam’s or Ord’s.

This is data from our long-term site. Photo credits: Merriam’s by Sarah Supp, Ord’s by Andy Teucher via ZoocodeZoo.com, Banner-tail by an unknown Portal researcher (i.e. we forgot to document who)

This all changes, though in the mid 1980s. Why? Blame Tropical Storm Octave which dumped nearly half of the annual rainfall in less than a week⁷. While the other kangaroo rats barely noticed this event, the Banner-tails hated it. Many individuals disappeared over the following months. The population tried to stage a comeback in the late 80s and early 90s, but like a one-hit wonder band, it fizzled. By the late 90s, the era of the Banner-tail was over. The last Banner-tail disappeared and there was much sadness among the researchers.

But you’ll notice some blips. Like a heart that beats irregularly, every few years a few little lost souls, wandering across the desert, find our site. Hopes and dreams of a new era of banner-tails spring anew only to be crushed by disappointment when once again they disappear.

Why did the Banner-tails disappear after Tropical Storm Octave and why can’t they seem to make it at our site now? It’s not entirely clear, but we think it has to do with shrubs. Banner-tails love grasslands. They don’t mind a scattered shrub here or there, but they don’t like too many shrubs ⁸. Sadly, since 1977, the site has become steadily shrubbier. Below are paired photos taken from approximately the same location at the site. On the left is Jim Brown on plot 4 in the late 1970s. On the right is 1995⁹. Notice any differences? The Banner-tails definitely do!

 

All of this is ancient history. So why blog about it now? Because we are happy to report the return of the Banner-tail! Well, kind of. I mean, we currently have one lonely female – probably fairly young given her weight and state of her fur when she showed up. We’ve caught her 3 months in a row now on plot 11. The students have joked about setting up a twitter feed for her. Tweets suggested include:

“4 months since I left home. The food here is great and all the other mice are small and easy to fight off. I’m gaining lots of weight”

“Returning to my favorite bed and breakfast this weekend. Predator-free and good but monotonous breakfast. Four out of five stars”

“Young professional female spectab [shortened form of the species name of Bannertails] seeking like-minded male. Looking for something casual and fun, no relationship. Interested suitors should arrive at Plot 11”

Needless to say, we’ve been excited by the Banner-tail. Every month we’ve been wondering “Is she still here?” One day, probably soon, the answer will be no because our site is too shrubby for a Banner-tail to be happy there, but for now we dream of fields of Banner-tails.

 

 

 

1. George Bartholomew and Herbert H Caswell. 1951. Locomotion in Kangaroo Rats and its Adaptive Significance. Journal of Mammalogy. Vol 32. Pages 155-169.
2. Glen Bradley and Roger A. Mauer. 1971. Reproduction and Food Habits of Merriam’s Kangaroo Rat, Dipodomys merriami. Vol 52 Pages 497-507.
3. Ana Davidson and DC Lightfoot. 2008. Burrowing rodents increase landscape heterogeneity in a desert grassland. Journal of Arid Environments. Vol 72 pages 1133-1145.
4. How Shakespeare should have written the opening to Romeo and Juliet. (Sorry, Shakespeare).
5. I had this data on hand and was too lazy to update with the newest data
6. How do we figure out energy use? We estimate it from metabolic rate. There is a well known relationship between the size of an individual and its metabolic rate – larger individuals have higher metabolic rates (i.e. they require more food per unit time than smaller organisms). We used an equation for the relationship between metabolic rate and weight that was calculated for wild rodents to figure out the metabolic rate for each individual and then summed across all individuals of the species.
7. Thomas J. Valone, James H. Brown, Carrie L. Jacobi. 1995. Catastrophic decline of a desert rodent, Dipodomys spectabilis: insights from a long-term study. Journal of Mammalogy, vol 76, pages 428-436.
8. Peter M. Waser and James M. Ayers. 2003. Microhabitat use and population decline in Banner-tailed Kangaroo Rats. Journal of Mammalogy vol 84. Pages 1031-1043.
9. I keep meaning to take a recent version of this, but haven’t remembered to do this when I’m at the site.

Another Source for Portal Project Related Posts

We have plans to write about some cool things going on at Portal right now: changes in the treatments at the site, beautiful winter annuals, some changes in the rodent community. In the meantime, I thought I’d point people towards Pacifica Sommer’s blog. Pacifica is a PhD student at the University of Arizona who has been using camera traps to study rodents. She’s been coming out to the site regularly to set up camera traps on our plots to compare what her camera traps are seeing with what our live-traps are catching. Her videos are a real treat and we’ve been luck to have Pacifica coming out to the site. She occasionaly writes about her Portal adventures on her blog. Here are some of her Portal related posts:

I have heard the howling of the grasshopper mice

Footage of the Mighty Predator: Onychomys torridus

Energy, Temperature, and Sex

Energy and Sexual Activity

 

The Portal Project Phase 2: Coming Soon

Winter annuals from 2012(?). Beautiful blooms like this seem to be an increasingly rare sight!

Stay tuned. The Portal Project blog is coming back on line with new material and new contributors! We’ve been busy at the site with some cool results and a new grant to fund new directions. We’ll start posting about it all soon. For those of you who follow this blog, previous contributors Sarah Supp and Glenda Yenni have both graduated, though they are both still working on Portal projects and come back to the site from time to time! Erica Christensen has taken their place and plans to post regularly about what’s going on at the site. In the meantime, let this beautiful picture by Glenda in the Portal archives suffice until we finish writing up some new material for the blog!

 

Portal at ESA 2011

If anyone still reads this blog, you may be wondering whatever happened to Portal. Well, rumors of our demise are…mildly exaggerated. Since I last blogged here, intrepid volunteers stepped forward and helped keep the project running on fumes. If you’re a Portal fan and you’re going to be at ESA this year, you should give the following people a hearty pat on the back (or better yet, buy them a beer): Kate Thibault, Karen Mabry, and Sarah Supp  (Glenda Yenni  is also on this list, but she won’t be at ESA this year, so you can just toast her in absentia). From May-December  of last year, we held things together with spit, duct tape, and fervent wishes. I even funded one of the trips by selling  a bunch of books to those used textbook people who seem to habitually lurk  the halls. Fortunately, Mother Nature was working with us and rodent numbers were so low that we could scale back our trips to every other month because rodent pressure on the exclosures was very low. Then the funding deities took some pity on us and we were awarded a 2 year NSF grant to keep the rodent side of things running. We’re still operating on some spit and duct tape, but we’re no longer hyperventilating. The plant side of things are a little more dire, but we’re all doing what we can.

Things at Portal are so not dead, in fact, that we have 4 different Portal presentations occurring at ESA this year. If you’re interested in hearing what’s been going on at the site stop by the following talks/posters (with short promos taken from their abstracts):

Tues: Multi-decadal climate cycles and the dynamics of a Chihuahuan Desert ecosystem. Morgan Ernest, Thomas Valone, James Brown. Poster Session 4:40-6:30 PM in Exhibit Hall 3, Convention Center

One of the greatest challenges facing ecology is understanding shifts in ecosystems that are being reported across the globe. However, understanding whether a particular shift in an ecosystem is the result of directional anthropogenic influences is complicated by the discovery of long-term climate cycles, such as the Pacific Decadal Oscillation (PDO), that fluctuate between alternative phases on decadal timescales. Because many currently operating long-term studies were implemented in the 1970s, 1980s, and 1990s, many of these studies have collected data only under one phase of these decadal-scale climate cycles, making it unclear whether the long-term trajectories documented in some ecosystems represent long-term lagged responses to large-scale shifts in climate due to naturally occurring climate cycles.

Thurs: Small mammal activities decrease soil organic carbon storage in dryland ecosystems. Jane Smith, Heather Throop, Thomas Valone, Morgan Ernest, James Brown. New Mexico State University. 8:20AM Ballroom F, Convention Center

Most of what we know about the terrestrial carbon (C) cycle comes from research conducted in mesic systems and dryland C cycling dynamics are more poorly understood.  However, arid and semi-arid systems cover 40% of Earth’s land surface and may provide an important C sink that will help mitigate the accumulation of CO₂ in the atmosphere.  In drylands small mammal disturbances such as digging and burrowing can affect a large proportion of the surface soil, and these disturbances have the potential to influence inputs to and stability of the soil organic carbon (SOC) pool.  We asked how small mammal activity affects SOC pools in dryland ecosystems. 

Thurs: Experimentally altering biotic interactions has different effects on static and dynamic macroecological patterns. Sarah Supp, Xiao Xiao, Morgan Ernest, Ethan White, Utah State University. 4:00 PM Rm 8, Convention Center.

A major focus in recent ecological research has been to elucidate if and when the details of biological interactions play a critical role in producing observed patterns of diversity.  Macroecology has increasingly become an important and popular approach in ecology. However, because it often ignores the inherent complexity within biological systems in its attempt to find generality across systems, its utility has been increasingly questioned. This has generated an important question: are macroecological patterns contingent on the specific networks of interactions among ecological particles or do patterns emerge from interactions regardless of the details of interactions?

Friday: Decline in biotic resistance and the reorganization of an annual plant community by an exotic invader. Ginger Allington & Thomas Valone, Saint Louis University. 8:00 AM Rm 10A Convention Center

Species interactions are considered an important mechanism that limits the abundance and distribution of exotic species, a process known as biotic resistance. Many studies documenting strong biotic resistance have been conducted over short time scales. However, given time-lags inherent in exponential growth and natural population fluctuations, the strength of biotic resistance may change over time.  Here, we use a thirty-year dataset to show an eventual decline in the strength of biotic resistance.