Portal Plant Census and Florida Hurricanes

September 18, 2017 by

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.

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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.

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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.

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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.

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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!

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Ode to six-legged wonder

September 8, 2017 by

If four legs are great, six legs are better. Right? For forty years now, the Portal Project has primarily focused on two-legged creatures trapping, studying, and sometimes cuddling small, furry four-legged creatures. But we haven’t ignored the six-legged inhabitants of our long-term research site, and I am going to tell you more about them now.

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Which one of these is least like the other?

I am the Ernest lab entomologist, who doesn’t consider herself an entomologist. I am interested in biodiversity, community, and macroecological patterns like those studied by generations of Portal rodent researchers. I just happen to study them using bees. There are over twenty thousand species of bees in the world, and about four thousand in North America. My research so far has focused on the community ecology of native bees in a global hotspot of bee diversity in California. But as fate or luck would have it, another documented haven for native bees lies just down the road from our long-term rodent site in Portal. Between 2000 and 2007, bee researcher Robert Minckley documented 383 different species and 69 genera of bees from the San Bernardino Valley of Arizona and Mexico. The Smithsonian’s Southwestern Research Station, which is nestled up in the hills only a few miles from our rodent site, also celebrates the insect diversity of this area with field courses focused on bees or ants that attract dozens of eager entomologists from all around the world every summer.

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Look familiar? This is the San Bernardino Valley on the border of Arizona and Mexico, just 50 miles south of our Portal research site. By BAlvarius – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11806210

A few months ago, I set out to see what kind of six-legged creatures we have scurrying around at Portal. My adventurous and ever-curious lab mates were willing to help, and (I think) even had a bit of fun learning to collect, pin, and curate bugs. During the March and May 2017 rodent censuses, we used a variety of passive (let the insects come to the trap) and active (go get ’em!) methods of insect collection to sample the local diversity on six legs:

  • Pan traps are brightly colored bowls full of soapy water that (passively) attract flying insects like bees that visit the bowls, fall into the water, and can be strained out and examined later.
  • Aerial nets (or “butterfly nets”) can be used to actively snag insects flying by or foraging on flowers, or can be used to more methodically sweep the ground to sample insects hiding in the grass or shrubs.
  • Blacklights lit underneath a white sheet at night passively bring in moths, roaches, and other nocturnal creatures that are drawn to ultraviolet wavelengths, perhaps because they confuse them with the moonlight they use to navigate, and can be scooped into collecting vials from their perches on the sheet.
  • Pitfall traps are plastic containers that are buried in the ground with their top openings flush with the ground level and covered with a coarse mesh with a hole in the center. Insects walking along the ground cross the mesh, fall into the hole, and are preserved in a small amount of ethanol at the bottom of the container. Do you think this is active or passive insect collecting? (Hint: we leave them out all day and only come back at dusk to check what is there.)
  • The crowd favorite was probably the “beat sheet,” which is simply a white sheet placed on the ground underneath an intriguing shrub, which is then vigorously beat with a piece of PVC pipe, a shovel, a hockey stick — really any bludgeoning tool will work. Insects that fall onto the sheet are then sucked up into an aspirator device — like a tiny, scientific, human-powered vacuum — and transferred into a collecting vial. This method of collecting is pretty active!

The spoils of our collecting efforts were creepy, crawly, and diverse.  The field crew had fun learning to pin them using the cooler and truck tailgate as our insect lab. Then I mailed them back to the lab and have been working on labeling, curating, and identifying our new Portal insect collection.

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Then just last week I took them to campus for a photo glam session with the fancy microscope camera. Take a look:

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I’m certainly not the only one who has been interested in the insect fauna in and around the rodent plots at Portal. Ants were actually a big part of the original research design. Between 1977 and 2009, ant colonies were censused once a year at every stake on all the plots, and between 1988 and 2009 ants were also baited (with Pecan Sandies!) and counted at 25 stakes in the thirteen unmanipulated plots. Research papers using this data, which is available to the public on the Weecology GitHub PortalData repository, have been authored by Tom Valone, Mike Kaspari, and more. Other brilliant ecologists like Deborah Gordon and Nate Sanders have also studied ant diversity, behavior, and community composition in the valley around our research site. I was actually following some of these researchers’ work long ago when I was first looking for graduate advisers and nerding out over my giant book about ants. And now here I am, working with the rodent branch of the legendary Portal Project while focusing on bees for my own work. It’s a small world after all, full of small six-legged wonder.

 

Learn more by checking out some of the published science on the ecological entomology around Portal:

Gordon, Deborah M. 1999. Ants at work: how an insect society is organized. Simon and Schuster.

Kaspari, M., & Valone, T. J. 2002. On ectotherm abundance in a seasonal environment—studies of a desert ant assemblage. Ecology, 83(11), 2991-2996.

Minckley, R. 2008. Faunal composition and species richness differences of bees (Hymenoptera: Apiformes) from two north American regions. Apidologie. 39: 176–188.

Sanders, Nathan J., and Deborah M. Gordon. 2003. Resource‐dependent interactions and the organization of desert ant communities.” Ecology 84.4: 1024-1031.
Sanders, N. J., & Gordon, D. M. 2000. The effects of interspecific interactions on resource use and behavior in a desert ant. Oecologia, 125(3), 436-443.
Valone, T. J., & Kaspari, M. 2005. Interactions between granivorous and omnivorous ants in a desert grassland: results from a long‐term experiment. Ecological Entomology, 30(1), 116-121.

 

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This four-legged creature thinks Portal is just the best place she’s ever been.

 

 

The Spectabulous Spectabs of Portal

September 1, 2017 by

Much beloved by those who have worked at the Portal Project, the banner-tailed kangaroo rat (Dipodomys spectabilis) is one of the most charismatic rodents at the site (for us smammal lovers who think rodents can be charismatic, anyway). The fact that they have a nickname—spectabs—attests to this fondness. Look at that mighty tufted tail! Those giant, majestic furred feet! Weighing in at over 100 grams as adults, they are twice the size of our other kangaroo rat species (D. ordii and D. merriami). What’s not to love?

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Dipodomys spectabilis

As avid readers of the Portal blog might recall, the site used to be much grassier back in the day. At the start of the project in 1977, spectabs were running the show at Portal; we even had some plots that excluded only D. spectabilis because they were so dominant! For the spectabs, this was a desert paradise, as they tend to prefer grassier habitats. As the site became shrubbier, however, the reign of the spectabs came to a slow end in the 1990’s. Since then, a few individuals have popped up here and there but haven’t stuck around, often heading for greener (grassier?) pastures.

For me, experiencing Portal for the first time in the summer of 2015, D. spectabilis seemed more like a mythical creature than a real species. I resigned myself to the probability that I would never actually get to see this massive kangaroo rat species and would have to be content with its smaller (and equally adorable, mind you) congenerics.

Then Stephanie showed up.

Of course, rodents don’t arrive at the site wearing name tags; names have to be earned. In April of 2016, Erica excitedly reported back from the field that she had caught—you guessed it—a spectab. This young female, weighing only 70 grams, was the first spectab caught at the site since a quick resurgence lasting from 2008-2010.

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We assumed she was just passing through. Yet May arrived, and there she was. I finally went out in June, trying desperately not to get my hopes of finally seeing a spectab too high. Over to plot 11 I went, my heart was pounding a little faster than usual. One of the first traps I picked up was very heavy! I’d caught my first spectab! I made my volunteer take a picture of me with Stephanie. You can’t quite tell, but I was teary-eyed with happiness; that might sound a little embarrassing, but I don’t mind admitting it. I was so excited! It felt like I’d completed some type of Portal rite of passage.

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Ellen (that’s me!) with Stephanie, who is far less excited about this picture than I am.

I’m not sure when I decided that our new resident spectab needed a name, but I unilaterally decided on Stephanie and, somehow, it stuck. Most of us assumed she’d disappear pretty quickly; since the 90s, most of the spectabs that have been caught have quickly moved on. And especially since she was young, we figured she was just on some rodent version of rumspringa. But month after month, there she was. Same plot, nearly the same stake every time. Spectabs are known for their well-kept, cultivated mounds, and Stephanie’s was shaping up over in the northwestern corner of Plot 11.

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A typical spectab mound: raised, multiple holes, and well-manicured.

Soon there was talk of whether Stephanie would get a “boyfriend” or not, which rapidly devolved into thoughts of setting up a twitter account for her or making her a profile on that new-fangled dating app, Granvr: the Dating App for Modern Granivores. Stephanie continued to grow, and we started wondering if she would be the exception to the 21st-century spectab rule and actually stay around. In the end, she stuck around for nearly a year; February was the last time we saw her.

Or was it?

In June, our newest Portal RA, Renata, was in her second month of training. We arrived at Plot 11, and what came out of her trap but a spectab! In shock and excitement, I lurched forward and grabbed the bag with the discombobulated rodent out of her hands without thinking or asking (not my best moment, I admit…). Stephanie was back! Or so we thought. Our volunteer managed to capture a dynamic set of pictures that explains the series of events better than any prose can:

Image uploaded from iOS

“Stephanie!!!?!”

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“Oh…hmmmmm.”

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“That is definitely not Stephanie…”

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“I shall name him Stephen!”

That’s right. I was holding a very scrotal male…definitely not Stephanie. Stephen hasn’t shown up again, and we assume he’s gone on his way.

Even though we have 40 years of data, the site is still reminding us that we have many unanswered questions. Where are these spectabs coming from? Where are they going? Why now? Will there be more? We sure hope so! And rest assured, we’ll report about them right here.

Portal Phenocam

August 25, 2017 by

You may have noticed the super-cool daily images featured in last week’s post. They’re from our new network camera.

For starters, it allows us to do things like watch our desert field site turn from brown to green in no time flat (and back to brown again this winter).

 

 

 

 

But even cooler, our camera is part of the PhenoCam Network. They’re organizing a network of near-surface remote sensing images from sites all over the world. This creates a time series of images, in RGB and infrared, that can be used for phenology monitoring by the PhenoCam folks, us, or anyone who’s interested.

 

 

 

 

The PhenoCam folks make all the imagery freely available to download. From installation and configuration to image analysis, they provide awesome support. And their R package phenopix provides a quickstart to using phenocam imagery.

How fast can a desert turn green?

August 18, 2017 by

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 1st was definitely not peak green:

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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!

 

 

Pregnancy in Kangaroo rats

August 9, 2017 by

~While everyone’s busy at ESA this week, we’d like to keep the 40th anniversary ball rolling with a guest post from a visiting researcher at Portal. Jess Dudley has been using the Portal area to compare pregnancy in kangaroo rats and Australian marsupials. We’ll be featuring other guest posts through the rest of the year. (If you’d like to do something similar, please send us your info!)~

 

In July 2015 I travelled the 24+ hours from Sydney, Australia to the beautiful town of Portal to research pregnancy in Kangaroo rats. To everyone’s astonishment we do not have Kangaroo rats in Australia! I am sure I don’t need to explain my fascination with Kangaroo rats with this audience but in terms of pregnancy they have some unique features which differ from most rodents. This finding by King and Tibbitts in the 1960’s led me to wonder how the placenta forms during pregnancy in these resilient animals. To answer these questions I was lucky enough to visit Portal twice in the summers of 2015 and 2017 to trap Kangaroo rats and collect tissue from the females. I have completed Transmission and Scanning Electron Microscopy as well as Western blotting and Immunofluorescence microscopy on the uterine samples from pregnant Merrriam’s kangaroo rats to determine what structural and molecular changes are needed for implantation of the early embryo and ultimately a successful pregnancy.

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Fat tailed dunnart (Sminthopsis crassicaudata) (https://museumvictoria.com.au)

 

My initial research into the molecular mechanisms of implantation and pregnancy began in an Australian marsupial species the Fat tailed dunnart (Sminthopsis crassicaudata) which has the same partly invasive placenta as the Kangaroo rat.

Fat tailed dunnart (Sminthopsis crassicaudata) (https://museumvictoria.com.au) range. IUCN (International Union for Conservation of Nature) 2016.

 

Through these comparative studies we have found that the molecular mechanisms allowing for successful pregnancy are conserved among eutherian and marsupial mammals during the early stages of pregnancy regardless of how invasive their placenta becomes.

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An Immunofluorescence image showing localization of adhesion molecules in green and cell nuclei in blue from a non-pregnant Merriams’ Kangaroo rat. Uterine Epithelial Cells = UEC. Lumen = L.

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Transmission Electron Microscopy image of uterine epithelial cells from a Merriams’ Kangaroo rat in the
early stages of pregnancy.

It has been an amazing experience to work in the Chihuahuan Desert. I was introduced to animals that I had never heard of and witnessed countless stunning sunrises and sunsets as well as beautiful starry night skies. It was an experience I will never forget. I would like to thank Glenda Yenni, Leigh Nicholson and all of the wonderful people at the Southwestern Research Station for their assistance and advice during the completion of this project.

nullA male K-rat hiding behind a SWRS intern (©Leigh Nicholson)

 

Jessica S. Dudley | PhD candidate
The University of Sydney

Portal at the Ecological Society of America Meeting

August 2, 2017 by

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 11th

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

July 26, 2017 by

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.

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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

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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.

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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!

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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.

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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

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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)

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The mountains are still stunning

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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 40th 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!

Walking the beat

October 12, 2016 by

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Last month we highlighted the brains (and a little brawn) of The Portal Project, with a description of the new regime shift research and the requisite hardware-cloth-battle of 2015.  This month we bring out the big brawn guns (and some brains) to show you how the site keeps its youthful glow year after year in the unforgiving desert.  If we could bottle this Portal magic, it would be a best-seller for sure. Here’s our best attempt:

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Do you like long walks in the desert?  Do you love cute, cuddly animals?  Do you like to take long walks in the desert with rattlesnakes, scorpions, and tarantulas when it’s 115 degrees out, and do you still love cute, cuddly animals when they bite you and poop on you?  If you answered yes to the last question, you might be Portal Protectors! material. (By the way, Morgan is recruiting another PhD student to work at Portal.  Please see her announcement about that here.) If you answered ‘yes’ to questions one and two but ‘no’ to question three, this blog post, accessed from the comfort of your armchair, is our gift to you.

To be a Portal Protector! is to be a biologist, a naturalist, an outdoor enthusiast/athlete, a team player, and a bit of a masochist. We get up early. We go to bed late. And we spend many of the intervening hours digging trenches, moving large rocks, pounding stakes into the ground, lugging heavy equipment to and fro, crawling around on our hands and knees amidst sharp objects, and catching small critters.  If any of these images below speak to you, then we’re on the same mental page:

Before you assume that these types of activities must only be for blockbusters, game shows, soldiers, or insane people, let us instead convince you how they are necessary and beloved steps in the quest towards scientific truth (I sense a blockbuster there…).  In fact, walking the beat of the Portal Project, including all of the aforementioned digging/crawling jobs, was the start to a successful career in science for a long and distinguished list of people.  Maybe you are one of them!  For that, we salute you.

Nearly every month, for approximately the last 453 months, one of the Portal Research Assistants has traveled to the site with a brave volunteer to census the rodent community.  Journeying from the original University of New Mexico headquarters, then from Utah State University, and most recently all the way from the University of Florida, they give up their weekends to keep the research going. (Keep the Lights Burning, Abbie…anyone?)  The current Portal RAs, Erica Christensen and Ellen Bledsoe, leave Florida on a Thursday to travel to Tuscon, Arizona, where they then pick up the truck, gather supplies and drive three hours to the site on Friday to set rodent traps on 12 of the 24 quarter-hectare plots before the sun goes down. Early the next morning they process the rodents caught in the traps, recording the species, sex, hind foot length, weight and pit tag number. They then bait and set traps on the other 12 plots to census the next nights’ activity, hauling wooden boxes of metal Sherman traps around a dizzying desert maze — like a Halloween corn maze, but made of spiny acacia bushes and located even more in the middle of nowhere.  After recording details about those rodents the next morning, they download data from the local weather station and make their way back to Florida by Monday night. It all looks something like this:

Many interesting scientific findings about how body size, metabolism, rain, species interactions, and temporal dynamics influence the structure of a rodent community, as well as a unique and impressive long-term community ecology dataset have come out of this workAnd since ecology is all about understanding the ways in which groups of living things interact with each other, additional results have come out of pairing the rodent census data with information collected twice a year about plants.

In both March and September of 2016, the current conglomeration of the Portal Protectors! traveled from Florida to Arizona to chase rodents, crawl around on our hands and knees counting plants, and perform our biannual trench-digging, rock-moving, stake-pounding, equipment-lugging rituals.  The Science Gods demand some weird sacrifices to ensure the everlasting bounty of Portal data.  And we must obey.  For the biannual plant census, we work together to record the sources of greenery around the site. We use meter quadrats (squares made out of PVC pipe, 0.25m on a side), placed at 16 permanent locations evenly spaced across each plot, to count and identify every tiny bud and blade of grass. We then string transect tape in a giant “X” across each plot and measure the width and height of every shrub it crosses. It’s spiny, tedious work. But the show must go on. In blistering heat and unrelenting sun, or through shivers and downpour, the plant census process takes about four long days each season, and looks something like this:

We often return from a plant census bruised, bloody, and burned, ready for a soft bed, a warm shower, a flushing toilet, and a clean shirt.  But we are only out there for a week.  Portal herself must endure the savage sun, devastating aridity, and seasonal deluges year-round.  Four-hundred and fifty-three rodent censuses and thirty-five plant censuses under the daily assault of the desert would take their toll on anyone.  So when the Portal Protectors! make our biannual pilgrimage from the lab to the site, we usually reserve some time, and some brawn, for a little Portal TLC.

Next time on the Portal blog, we’ll unveil both the long-overdue makeover of Plot 24, and our brand new shiny weather station!  This is where all the real trench-digging, rock-moving, stake-pounding, and equipment-lugging comes into play.  We might even include some original pictures of us doing these activities, instead of just George Clooney’s excellent portrayal of our work.  So stay tuned.  And stay safe.  It’s a crazy, dusty, desert world out there. But someone has to keep the lights burning.

abbie

ALL GOOD THINGS MUST END, OR SHIFT

August 3, 2016 by

We return this week from our special, breaking-news post about the recent reappearance of our one-hit-wonder, Twitter-sensation, spectabulous Banner-tailed Kangaroo Rat. This T-Rex of Portal may not be here to stay, but we’re sure excited she stopped by. What is here to stay is that pesky plot switch we mentioned last month. We’re going to continue our series of Portal science updates and tell you all about that now:


REGIME SHIFTS AND A NEW FRONTIER AT PORTAL

The last time we checked in at this blog prior to the 2015 plot switch, Erica was battling monsoon season to record desert rodent dynamics on the twenty-four long-term experimental plots that have been censused almost monthly since the site was established in 1977 by James Brown, James Reichman, and Diane Davidson. That’s thirty-nine years of tracking the occurrence of various species of small mammals. That’s over four hundred visits to Portal, AZ to trap, measure, weigh, and tag rats. And it all started before scientists had thought very much about why fluctuating species abundances in a community might be interesting.

This is cool because now we have decades of data (most of it publicly available) on how these scurrying, hopping, burrowing creatures have been interacting at Portal, just in time to see a surge of researcher interest in community ecology and species dynamics. For example, we were able to document an abundance of the small, pink flower Erodium cicutarium in plots where the competitive seed-foraging Kangaroo rats were excluded (Allington et al, 2013). And, after many years of pondering its absence, we recorded a resurgence of the Northern pygmy mouse, Baiomys taylori, a peculiar trend that would have gone undetected without regular sampling efforts. We’ve seen shrubs increase in both size and abundance, changing the entire look of those plots, not to mention the nature of the local foraging and shade resources. Ecology, in all its complexities, happens over long time scales. To understand it, we must record it over short ones. Few studies exist that have managed to do both, and we are excited about the scientific opportunities the history at Portal affords us and others who use our data.

Erodium cicutarium (left) has been increasing in abundance in plots where Kangaroo rats are excluded.  Baiomys taylori (right), the Northern pygmy mouse, has resurged from apparent rarity.

So now that we have amassed this monstrous dataset and finally understand more about how these rodents have been faring, cohabiting, and influencing the plants of these twenty-four plots in long-term treatment groups over nearly forty years, naturally we decided to turn it all on its head. Yes, after over four hundred samples of the twenty-four plots in their original treatment states, we got a grant from the National Science Foundation to switch them all around. Why? Because we’re scientists, and we like to poke systems to see what happens.

Because we scientists often want to be useful in addition to curious, we also like to simulate real expected ecological change so that we can predict likely outcomes and plan for them. Our world is rapidly changing. We need to understand how ecological communities will respond. When we’re not watching and recording, or sometimes even when we are, seemingly small changes can add up to big shifts. A breeze, a little water vapor, a small temperature change can suddenly turn into a monstrous hurricane, for example, that introduces a whole new set of rules and challenges to human existence.  Similarly, ecological systems can undergo extreme, abrupt changes in state that are very hard to understand and manage unless they have been tracked before, during, and after that transformation.

Questions surrounding the idea of regime shifts, described as dramatic changes in populations, communities, and ecosystems over short periods of time (Hare & Mantua, 2000), represent relatively new challenges in the field of ecology, ones that the Portal project may be uniquely situated to address.  Understanding regime shifts, or how communities of rodents may suddenly shift in their relative species abundances or resource usage, at Portal may help us understand what to expect from other ecosystems undergoing unprecedented levels of environmental change.  We’re not promising X-(woman)-like vanquishing of Hurricanes. We study rats, not wolverines after all. But this is important stuff.

Hurricane

While hurricanes are exceedingly rare in the Arizona desert, there are subtler forces at work which may cause shifts in our Portal rodent community. Knowledge of these forces may help us, and other scientists, understand similar sudden disruptions in unmonitored groups and ecosystems. It’s the scientists’ mutant superpower — studying one thing ‘over here’ can help us predict and manage another thing ‘over there’ which we may have actually never seen…except in our mind’s eye.

The figure below, from Dr. Ernest’s 2014 grant proposal, shows three scenarios in which ecosystems and drivers (e.g. climate, nutrient input, biotic interactions) can be related in ways that might represent system-disrupting regime shifts. Sudden shifts in drivers (e.g. hurricanes) could cause a corresponding shift in ecosystems (e.g. massive urban destruction), which would constitute a regime shift. The same ecosystem pattern, however, could be triggered by simply crossing a threshold along some seemingly innocuous linear increase of a driver (like a slowly rising sea level that causes the sudden collapse of a city when it finally submerges the business district, or the state of water as it’s gradually heated past its boiling point). Regime shifts, like the melting of sea ice caps, can be hard to undo. Sometimes an ecosystem can be brought back down from a boil by turning down the driver dial. But sometimes an ecosystem will fail to revert back to its original state after a driver has increased and then decreased again, taking the ecosystem along a new trajectory. At Portal, where neither massive urban destruction nor hurricanes are a major concern, this might come in the form a plant that fails to return to a location after a particularly dry summer even after rains have resumed, or a Banner-tail Kangaroo rat who once reigned mighty and may never be seen again.

Fig1


To poke the system and test this at Portal, in March 2015, we reversed some of the long-standing plot treatments. We also, of course, maintained some of the plots in their original treatments to serve as reference plots, against which we can test the existence and magnitude of potential regime shifts caused by introducing a large granivore as a driver. This has rarely been experimentally tested because few systems have the long-term data, ability to simultaneously cause a jump in an ecosystem driver in both directions, and enough plots to maintain replicates with reversed and reference plots.

Fig2

The Portal project’s twenty-four plots and well-monitored, gated rodent communities is an ideal system to study regime shifts because it does not have these common experimental design limitations. Because we manipulate rodent access to plots via gates of different size, it is also shockingly easy to change the rodent community on a plot – we can make new gates by clipping holes in the fencing, remove gates by applying patches over them, or change the size of gates (and the species that can enter the plot) by either patching or clipping to create new hole sizes. So last spring, Dr. Morgan Ernest led the hardware-cloth-stripping-team in reassigning plots to their new experimental treatment, ending an era, but never the science:

Erica securing the new hardware cloth pieces to close the old gates (left).  This little guy (right) wishes we could strip the hardware cloth off him.  But we are done with that task.

In a gesture of inclusiveness and diversity characteristic of the Weecology lab group ideology, we broke down barriers between different rodent communities by enlarging or creating gates in some of the plots that had previously excluded the granivorous, large-skulled (and adorable) Kangaroo rats:

KRat

A Kangaroo rat, Dipodomys merriami.  What plot wouldn’t want these cuties?

But because this is science and not social revolution after all, we are also testing the influence of these large-skulled favorites as ecosystem drivers by excluding Kangaroo rats from some of their previous home plots by patching up or narrowing gates in plot fences that had previously allowed them to pass into these areas.

Example of a gate in a Control plot, open (left) and closed (right), which provides free, open access for all knowledge-(or seed)-seeking rodents!
Example of a gate in a Kangaroo rat exclosure plot, open (left) and closed (right), which is very oppressive of Krats, but great for controlling their influence in plots as a driver.

 

In case you have ever doubted the dedication of field biologists, thinking perhaps that we enjoy a life of sipping Coronas in a scenic field station after a day of wandering through the hills sniffing at plants, we would like to explain to you the unnatural nature of hardware cloth. Hardware cloth is not cloth. It is, however, hard. It is also pointy and sharp and vexingly narrow. To enact the plot treatments switch described above, the valiant hardware-cloth-team-of-2015 used pliers to strip countless thin layers of wire off of small metal squares of fencing, creating exposed, pointy wire ends along the hardware cloth, which must then be woven through the tiny squares in the existing plot fence to close off or narrow old treatment gates. They then cut or adjusted new treatment gates in the existing fence hardware cloth to create new access for the Kangaroo rat ‘drivers.’ Science is not all high-tech gadgets and sophisticated computer algorithms. Sometimes real science is stabbing yourself with hardware cloth one thousand times and squatting on the ground in the blazing hot desert to sew patches over gates in metal fences because you want to see what the rats will do. We happen to actually love this type of self-brutality in the name of science, and how it makes our evening Coronas, enjoyed together around the campfire at our beautiful field station, taste that much better.

Ramada

The field crew taking a break at the Ramada, our two-sided field station.

And that is the story of how the plot switch, and the finger-massacre, of 2015 was recorded in Portal history. We won’t show you the blood, but we will show you the final plot map result, and a much cleaner schematic of plot treatment shifts:

Fig3

Fig4

 

Next time on the Portal blog we will fast-forward to a year after this historic plot switch when, wiser, hardier, and with more Band-Aids and guacamole in tow (though there is never, ever enough guacamole), the Weecology field crew hit the road again, in our new University of Florida vehicle, to undertake the 447th sampling of desert rodents, and the twelfth under a possible new regime.