Archive for September, 2017

2017 Summer Plant Census

September 29, 2017

Twice a year the Portal crew gets a little larger, and spends a few extra days, and we count plants on all 384 quadrats. Despite some of us being in our second decade of visiting the site, and everyone on the plant crew being intimately familiar with most of the species at the site, and that the rodent RA has been watching the plants grow and giving us monthly updates, we still never really know what we’re going to find once we get out there. The desert does what it wants.

The uncertainty seems especially high for the summer plant community. Some years we arrive to an ocean of grass, waving in the breeze. Those are the years we spend a lot of ‘quality time’ with each quadrat. Other years we arrive to a dustbowl. We walk around the site laying our PVC quadrat down and picking it back up again and saying ‘zero’ 384 times. [Okay, we don’t really ever get all zeros. But it feels like that when you’re out there.] And some years we show up to find some new arrivals, species that finally decided to show up after 40 years. Then we spend less time counting individual blades of grass, and more time pouring over our regional species list and plant ID guides.

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Summer 2014, Morgan, Tom and Erica counting Aristida adscensionis and Bouteloua aristidoides, a lot of it

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Summer 2015, ‘Who are you and where did you come from?’

 

This summer was pretty good for forb diversity. Forb species like Dalea, Cassia, Kallstroemia, Ipomea and Sida were relatively abundant.
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Kallistromia

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In the summer we also measure shrub cover on the plots, so we get some bonus quality time with the plants.

 

There are lots of other bonuses to the summer plant census that make up for the brain-melting heat. As we’re walking around the plots, we get to see snakes (Mojave rattler, Common king snake, gopher snake, coachwhip, and Coral snake on this trip), horned lizards, turtles, tarantulas and exceptional insect diversity that are not out and about from October to May.

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And there’s nothing like a Portal monsoon sunset.

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Portal Plant Census and Florida Hurricanes

September 18, 2017

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.

Hermine

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.

Newton

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!

Ode to six-legged wonder

September 8, 2017

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.

Davidson, D.W., Inouye, R.S., Brown, J.H. 1984. Granivory in a Desert Ecosystem: Experimental Evidence for Indirect Facilitation of Ants by Rodents. Ecology, 65(6), 1780-1786.

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

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.