Friday, January 11, 2013

Student Film Festival: The Horrors of Invasive Plants

For those floraphiles out there who are also cinephiles, this post is for you.

Georgia Tech Students Study Streamside Urban Restoration

The Atlanta Botanical Garden recently played host to a mini-film festival.  The filmmakers were Georgia Tech students enrolled in Dr. Cara Gormally’s Biology 1511 laboratory.  The films capped a semester-long project investigating the biological effects of the Urban Habitat Restoration Project[1] at Mason Mill Park, part of an initiative to remove invasive species and restore native habitats in public parks and other areas in metro-Atlanta.  The class was divided into three groups tasked with generating a research question and a laboratory experiment designed to investigate it.  The students then wrote up their findings.  Finally, each group made a short educational film explaining a couple of concepts central to their research.  The films had to be narrative and were graded on their educational and entertainment values.

A number of people with a special interest in urban habitat restoration attended the screening:  David Butler, Dekalb County Greenspace Environmental Manager; Sally Sears, Executive Director of the South Fork Conservancy; and Dennis Krusac, Endangered Species Specialist at USDA Forest Service and Director of the Greater Atlanta Pollinator Partnership (GAPP).  Jenny Cruse-Sanders, Director of Conservation and Research at the Atlanta Botanial Garden introduced the films.  Marc Merlin, Director of the Atlanta Science Tavern, was also present.

The English ivy (Hedera helix) at Mason Mill made a strong impression on these students, and, according to Dr. Gormally, most were unaware that it is an invasive plant.  Whether due to its ability to outcompete every other species or simply its dark, leafy charisma all three groups chose to profile English ivy.

Without further ado, here are the films.

Biology Nightly

Filmmakers/Authors:  Elizabeth Burns, Tyler Clenney, Angela Como, Seth Dubin, Alex Huhman, JJ Netter, Kathryn Martin, Graham Sweeney

Paper title:  The effect of the invasive species, Hedera helix, versus the native species, Vitis rotundifolia, on soil microbial communities

Research question:  Do invasive plants affect the microbial communities in their root zones?  If so, does this have anything to do with their success as a competitor?

Floraphile review:  This newscast format features some professional-looking graphics and person-on-the-street interviews from the Georgia Tech campus.  What makes the former teacher in me want to stand up and cheer is that these students listened to the input from the audience and revised their film.  In this final version they define their terms, include material about how you can rid yourself of invasive species and suggest plants to use instead of English ivy. 

Audience questions/comments:  The students found more species of bacteria present in English ivy’s rhizosphere, and Dr. Jenny Cruse-Sanders encouraged the students to identify the bacteria. 

Bio Minute News

Filmmakers/Authors:  Laura Boyle, Meredith Christianson, Jessica Huynh, Drake Lee-Patterson, Diane Lin, Bonnie Rowland, Emily Slater

Paper title:  The Effects of Restoration on the Diversity of Species Present in the Soil Seed Bank at Mason Mill Park

Research question:  Does the seed bank (natural storage of seeds, often dormant, within the soil of most ecosystems) of a restored area have a greater diversity of seeds than that of an unrestored area? To assess the success of the restoration of native species in Mason Mill Park and understand the effect of invasive species on soil seed banks, this group examined the seed abundance and diversity of the seed banks within three different plots.

Floraphile review:  With this film we have a blending of genres:  newscast + horror film.  A monster, English ivy, is on the loose and attacking native plants: shading them out, taking their nutrients, and choking them in vines.  A very spirited performance of “English ivy” provides an excellent overview of how this invasive species displaces native species.  The revised version of the film is more informative and makes a wise substitute of the Southeast’s super invader, Kudzu, for the California scourge, ice plant. 

Audience questions/comments:  Dennis Krusac of the US Forest Service urged to the students to germinate the seeds they collected so that they can identify the plant species and learn what percentage of the seeds are still viable after years spent in the shade of English ivy and other invasives.

Felix, Killer of Hedera helix

Filmmakers/Authors:  Katie Fiedler, Sarah Gould, Chris Harwell, Meera Kuntawala, Riz Rafi, Kyle Sexton, Casey Smith, Mary Ann Thaliath, Neha Zaer 

Paper Title:  Functional Traits of Hedera helix compared to Vitis rotundifolia and Smilax rotundifolia

Research question: Why is English ivy such a good competitor?  This group compared Hedera helix leaves with those of two native species, muscadine grape (Vitis rotundifolia) and roundleaf greenbrier (Smilax rotundifolia).  They found that ivy has larger leaves, covers more ground, has a greater biomass and the leaves themselves have a higher nitrogen content than the two native species. 

Floraphile's review:  Felix, Killer of Hedera helix is a great spoof of Dexter, the TV show about a serial killer who preys on serial killers.  It probably got the biggest laughs.  Kudos to the filmmakers for working factual information into the dialogue, and to Meera Kuntawala for her megalomaniacal "English Ivy." 

Audience questions/comments:  Do you think people would quit planting English ivy if they knew what a scourge it is?  How do you get rid of it?  What should you plant instead?  What can serve as replacement for this seemingly maintenance-free groundcover? 

Students Embrace Native Aesthetic

Student comments:  The students said repeatedly that they appreciated doing a “real” lab rather than following a set of instructions toward a known outcome.  They also felt that devising their own research question, from a real-world situation like the Mason Mill Park restoration, gave them more investment in their research.  While working in a large group was sometimes challenging, finding times when they all could meet, for instance, the students thought the group project instilled the idea that science is collaboration, not a lone scientist gazing into a microscope.  A number of students were keen to remove English ivy from their campus.  Its omnipresence made it possible for students to film on campus, but it also got them thinking about the landscaping choices in their immediate surroundings.

Final remarks:  You learn just how well you know a thing when you are asked to teach it to someone else.   Of course, it’s not just how well you know a subject, but whether you are able to convey that knowledge to a particular audience.  You must internalize the perspective of your audience:  What do they know?  What knowledge and conceptual storehouse can I draw upon?  How can I draw on this storehouse to best convey a new set of ideas? 

An analogy that two of the films used was English Ivy as alien monster.  In this context I think the analogy is apt.  First, it’s quite a familiar narrative: From 1950s monster movies to episodes of Fringe, stronger, faster, smarter aliens come from outer space or another dimension to take over the world.  Second, English ivy is a species alien to this continent, and it really does compete like mad, engulfing native habitat and converting a varied landscape into a uniform sea of ivy, even bringing down trees in its wake.  Like “English Ivy” says in Felix, Killer of Hedera Helix, “I’m just better than all of them!”—better at ecological domination, that is.

So, for a teaching tool, the film was a great assignment.  It reinforced newly acquired knowledge and taught the students how to convey specialized knowledge to a general audience.  The hoped-for happy result is that the students will become scientists who can talk intelligibly about their work with regular folk. 

[1] Urban Habitat Restoration Project partners:  The Atlanta Botanical Garden Inc., Georgia Plant Conservation Alliance, DeKalb County Natural Resource Management Office, Atlanta Audubon Society, Chattahoochee River National Recreation Area, National Wildlife Federation, Butterfly Conservation Initiative and Georgia Public Broadcasting.  Funding sources:  Environmental Protection Agency (EPA), National Fish and Wildlife Foundation/Georgia Power (Southern Company) provide funding through their Five Star Grant program.

Friday, March 23, 2012

The Great Georgia Aster Hunt, Part 2: Appalachian Terminus

A view of a ridge of the Southern Appalachian Mountains of Alabama.
Leaving Talladega, we head southwest toward West Blocton and the very terminus of the Appalachian Mountains.  Being a Californian, I have a truly wretched knowledge of geography (see floraphile, post 1 for explanation), so I was shocked to learn that the Appalachians extend into Alabama.  Here the mountains, perhaps the oldest and once the tallest, have eroded for hundreds of millions of years into a series of ridges and valleys.  The road we drive twists and turns along their contours.  It’s late afternoon and we are scouting locations for the real search tomorrow.  Traveling alongside the Cahaba River National Wildlife Refuge, we look for the turnoffs, bridges, intersections and other features near our map points.  
The same geology that made Pennsylvania, West Virginia and the rest of Appalachia mineral rich is at work here.  This is old coal mining country, but the signs of a once dominant industry are now absent, with the exception of a few historical plaques.  People still live here, but it’s not clear what they do for a living.  The plaques intrigue me.  They commemorate the company towns where miners and their families lived.  My secret hope is that our hunt for Georgia aster will take us to these ghost towns and their abandoned mines.  
The communities along the old highway show signs of poverty.  Unchecked kudzu undulates along with the topography and engulfs abandoned homes.  Below one ruined dwelling I see a kitchen sink lying where it fell through the floor.  More than one emaciated hunting dog approaches the car.  They don’t bark at us, just peer inside with desperate eyes.  This atmosphere and the oncoming gloom of the setting sun put us on edge, so that we jump each time we pass the same waving bag caught in the limb of a tree.
Also eerie are the blow-downs.  Alabama was visited by a series of deadly tornadoes last April, and Bibb County was not spared their destruction.  The road is lined by forest, but when we hit a blow-down, the horizon opens because the forest is lying flat, like God is the middle of a game of Pickup Sticks.  Portions of trees remain vertical, twisted and splintered where the wind sheared them in half.   It must have been terrifying to be anywhere near here.
The effects of one of the tornadoes from last April. 
The blow-down gives me an opportunity to display my abysmal sense of direction.  We see one after another, which prompts me to exclaim, “My God, how many tornadoes went through here!”
Without a hint of disgust, Jenny replies, “Actually, it’s same blow-down.  The road is just winding through the tornado’s path.”
Sitting in the passenger’s seat designates me as navigator, but, as I have just shown, I am hopeless in this role.  Fortunately, Jenny has a sense of direction like some people have perfect pitch.  And she only has to glance at a map to orient herself.  But I am not completely useless.   In fact, as it would turn out, I have a somewhat uncanny ability to spot Georgia aster.  It helps that the flower is a very particular, vivid purple.  If Jenny can get us to the spot—no small feat given the sketchy descriptions we have of sites that haven’t been visited since the early 1990s—I’ll find what there is left find.
Jenny wants to look at one more location before we call it a day.  One of our map points is right next to Highway 10, so we drive through West Blocton and pick up the 10.  We pull over at what seems a likely spot and get out.  We scan the roadside: nothing.  We see a power-line cut that runs along the highway and begin walking, each taking a side to scan.  Still nothing.  The sun is down now, but there is some residual light.  Jenny is utterly unstinting when it comes to fieldwork (and, I suspect, work in general).  On another plant survey, a colleague half-jokingly remarked to Jenny, “You know, the plants don’t glow in the dark.”
Georgia aster: A vibrant, but not bioluminescent purple.
And then I see a spot of purple—The Purple.  It is indeed a Georgia aster, and at its center is a sleeping bee, florets clasped to its abdomen.  A moment before we were ready to turn back, but having found one, we had to look for more.  In the poor light, we stumble over the uneven ground.  But that was it.  Just one flowering plant left in what was once a modest population.  At least we know we were in the right place. 
That night, when I close my eyes, I see asters, or sometimes just The Purple.  Jenny tells me in the morning that she dreamed of grids and maps assembling before her.
See any purple?  Nope, me neither.
The next day is one of frustration. We meet Sarah Clardy, Manager of the Cahaba National Wildlife Reserve. She very generously spends a good bit of the morning with us as we fruitless search.  She is interested in the rare flower growing in her park.  And I am relieved when we that we find a couple of clumps in a power-line cut—Sara sighting one of them herself.  Not a complete bust, but for a small community to count, we need a minimum of 30 stems. Not even close.
Refuge Manager Sarah Clardy and Jenny Cruse-Sanders.
I ask Sarah about Piper, Belle Ellen and Coleaner, the company towns honored on the historical markers. 
“Oh, there’s nothing left,” Sarah says.  “The mining companies bulldozed them when it was no long profitable to mine here.  I heard they offered to sell the workers the houses, but they never made enough to meet the price.” 
I picture bulldozers pushing a wrecked town into a derelict mineshaft. 
Sarah leaves us to continue our hunt, which we do without result.  To stay on schedule, we need to find one more population, and the afternoon is getting on.  We decide to head to an isolated Baptist church, which our map shows had several populations.  Jenny’s navigational exertions are given a rest since a large, white sign with black lettering points the way to the church at each turn.  We arrive in broad clearing in the woods to find a blindingly white church surrounded by a blacktop parking lot.  The lines marking the parking places are so white they could have been painted yesterday.  Directly across from the church runs a creek.  Where the creek widens a bit, there are benches.  It occurs to me that these are real Baptists, who make use of the creek.  

Sadly, there is no point in searching for the creek-side population our map shows, since a lawn mower has been run right up to water.  These Baptists are big on maintenance, which is a testament to how much to revere their church and no doubt is a big reason why the church has survived more than a hundred years. Nevertheless, I take a mean pleasure in imagining the whole congregation, including grandmas and babies, with high and tight buzz cuts.
We walk the line:  Surely we'll find some over the next rise.
Jenny and I scramble across the creek and climb up the steeply wooded hillside opposite.  At the top we find a power-line cut.  It is sunny and hot.  I find an aster and mark the spot with the pullover I’ve shed.  We both expect that over the next rise we will find a true aster community, but what we find is just more pine saplings, shrubby growth, and, of course, catbrier.  The latter I have begun to think of as my personal cross.  Maybe it is the closeness of the church, but as I pull the catbrier from my thigh for the umpteenth time, I decide that when God curses Adam and Eve and speaks of thorns and thistles, He definitely had catbrier in mind.
Back at the car, hot and dispirited, Jenny and I consider our next move.  She fishes in her bag and pulls out a couple of peanut butter cups culled from her kids’ Halloween candy.  As she hands me one, Jenny says, “One of my professors always told us to have a piece of chocolate and look again.” 
According to our information there is an aster population behind the church cemetery.  And conveniently there is paved drive, so we hop in the car.  Jenny drives slowly, and we both chat animatedly trying to cheer the other, but neither of us has any real hope at this point. 
Then I see spots of purple against a low berm on the backside of the cemetery.  We see asters, lots of them.  We get out of the car and leap around.  The chocolate worked!  We have some more to celebrate, although what we both want now are cold beers.  Drinking in a church cemetery seems pretty wrong though (not that we have any with us), especially under such a frankly blue sky.  So, beerless, we set to work lying down our transect and marking stems to sample.  We estimate more than 300 plants.
Our work done, we head back to Atlanta.  It’s good to be going home, but this region haunts me.  It seems forsaken.  The forests were logged and carried away by rail, and what has grown back or was planted appears tenuous.  A once booming industry seems to have evaporated, leaving little of its infrastructure as reminder.  And a formerly massive mountain range has been worn down to inconsequential elevations. 
Nevertheless, there are signs of persistence.  People still make their home here, and they are proud of their history and of the lilies that bloom, like a miracle, in the middle of the Cahaba River. 
Cahaba lilies (Hymenocallis coronaria) blooming last May. Credit: Cecil Holmes.

Saturday, February 4, 2012

The Great Georgia Aster Hunt, Part 1: Talladega Day

Georgia aster in a typical roadside location.

Quick:  What’s the state flower of Georgia?  Did you guess the Cherokee rose?  Ten points for Gryffindor!  

Like many states, Georgia chose a non-native plant for its floral emblem.  Sometimes native-plant geeks toss around homegrown alternatives for our state’s flower.  For a time I was crusading for the Georgia aster (Symphyotrichum georgianum).  It has Georgia in both its common and scientific names, and the flower is a lovely shade of purple.  But it also has one great big drawback: The Georgia aster is so rare that few Georgians have ever laid eyes on one.  And what fun is a state flower you never see?
         This rare plant is only growing rarer.  Georgia aster is a candidate for federal listing under the Endangered Species Act.  About 30 populations had been observed in Georgia, but only 15 small populations survive.[i]  Georgia aster requires prairie-like conditions to grow and seems to prefer disturbed, bare patches of ground. A relict species of post oak savannas that existed in the southeast before widespread fire suppression and the extirpation of large native grazing animals, Georgia aster now grows in places where land management creates similar conditions: roads, railroads and utility rights-of-way like power-line cuts.  The species is further threatened as maintenance practices shift from mowing to spraying herbicides.  Georgia aster’s range includes Alabama, North Carolina, and South Carolina, but has but has been extirpated from Florida.[ii]
Right-of-way marker
         With the populations diminishing not only in numbers but also in size, another knock against the species is the threat of genetic depression.  Plants can reproduce sexually or, in cases like the Georgia aster, they can increase vegetatively through rhizomes (horizontal underground stems which puts out lateral shoots and roots).  All the growth you see in a small community could be from a single clone.  And as we all know by now, poor genetic diversity leads to poor survival rates in all species.
Studying the Means to Thrive
Jenny Cruse-Sanders, Director of Conservation and Research at the Atlanta Botanical Garden, and Danny Gustafson, a professor of Plant Molecular Ecology at The Citadel, are conducting a study of genetic diversity and seed viability for the species across its range.  The hope is that the results can inform the management of the remaining populations.  For instance, with a genetically inbred population, managers could plant asters from other populations and increase the genetic diversity.  Or, if the plants are producing seed but they aren’t growing into plants, then perhaps there is some other issue: Not enough bare soil, mowing at the wrong time, or not mowing often enough.  

This roadside population was mowed while in bloom.  Only the plants hanging over the embankment were spared.
         This is where I come in.  For the study, Jenny and Danny need leaf and seed samples from large and small populations across the aster’s range.  Leaf samples had been collected from Georgia and the Carolinas, but none from Alabama.  Jenny and I were in Alabama to find 6 populations of Georgia aster, 3 large and 3 small; take GPS points; map the boundaries of the community of plants; and take leaf samples for genetic analysis.         
Ryan Shurette and Jenny Cruse-Sanders surveying the large Georgia aster population beneath power-lines in the Talladega National Forest.
Our first stop is the Talladega National Forest, midway between Atlanta and Birmingham.  At the ranger station we meet up with Ranger Ryan Shurette, Forest Botanist, who shows us the way to a field of aster growing in a broad power-line cut.  Prairie plants are never what you call lush, but what we see is certainly robust.  The asters are waist-, even chest-high and festooned with blooms.  At around 2,000 plants, this would turn out to be the largest population I was to see.  Ryan is clearly doing a great job of managing it.  He’s even added out-plantings that are doing quite nicely despite the wretchedly hot, dry weather of this past summer.  
Such a profusion of blooms is truly a rare sight.

A Vital Collaboration
While we were working, employees of Alabama Power showed up to talk to Ryan about upgrades to the power-lines and their impact on the asters.  Jenny and I had lain our transect, and while Ryan shot the breeze with the Alabama Power guys, he also helped record our data. They mainly talked hunting and fishing.  I might have been irritated with Ryan for dividing his attention this way, but I had recently been witness to the importance of having a good relationship with the utility that maintains the power-lines running above rare species.
A few weeks before, I had visited a site in North Georgia with a good-sized aster population.  They, too, were growing beneath power-lines.  Due to some miscommunication, a maintenance crew had sprayed some of the asters with herbicides, intended no doubt for the long-leaf pines that left unchecked would interfere with lines.  On our first visit to the site, the sprayed asters were stressed, and on our second they were a crispy black.  These rare plants were well and truly dead.  Fortunately there were still over 100 healthy plants, but it was a blow nonetheless, and an avoidable one.

The effects of herbicide.  Aster can be seen in lower-left corner, stretching into the middle of the frame.
That the Alabama Power folks were having a nice long chat-and-chuckle with Ryan was not entirely surprising.  Ryan is Southern charm distilled, and it is encouraging that these asters have him as advocate. 
We had just finished our work when the sky opened with the heavy rain shower it had threatened all morning.  We hustled back to our cars.  The way to the asters had involved many turns down largely unmarked roads.  “I can carry you out,” Ryan offered.  When my brain clicked back in gear, I realized he meant take us out, lead us out in his car.  I’ve been living in the South for the better part of three years, and southern idioms still sometimes catch me by surprise.
Perhaps More Than Kissing Cousins
I’m glad that we saw the Talladega population first.  As they almost always are, the Georgia asters were growing among a related species, Symphyotrichum patens, and it gave me the opportunity of making a direct comparison between the two.  The species are difficult to tell apart.  The floral rays of the patens are smaller and lighter in color; the leaves are softer and narrower and lack the scabrous texture of georgianum.  The give-away is that the patens blossom has a yellow center.  I looked closely at the plants and touched the leaves of each species to see and feel the differences.

S. georgianum and S. patens: Can you spot the difference?
As I did so, all kinds of pollinators visited the flowers, traveling back and forth between both species.  Which brings up another tricky variable.  Jenny told me that S. georgianum and S. patens may be hybridizing.  They bloom at the same time and clearly share pollinators, so they have the opportunity to do so.  Moreover, we saw at the Talladega population, as were to see at other sites, individual S. patens that exhibited traits of S. georgianum, and vice versa.  Some S. patens had longer rays and rougher, broader leaves, while some S. georgianum blossoms were lighter in color and some had softer leaves.
None of these observations are conclusive of hybridization, especially since asters tend to exhibit a lot of variation plant-to-plant, but they certainly are suggestive.  This makes the problem of protecting S. georgianum even more complicated: How can you set guidelines for a plant’s protection if you cannot fix its taxonomic description?  You could even say that we may be losing S. georgianum to this process, but you could also say that hybridization is the key to its genetic survival: S. patens is flourishing, while S. georgianum is dwindling.  The S. georgianum traits could survive in a perhaps more vigorous and abundant hybrid.
Thanks to Talladega we had our “search image” firmly in place, which would prove vitally important.  We had sketchy information about the locations of the remaining Alabama populations, many of which had not been visited since the 1990s and, as we were to learn, had drastically diminished in size.  From the Talladega National Forest, we headed southwest to the terminus of the Appalachian Mountains, the haunting country that was once at the heart of Alabama’s coal mining industry.

[i] Chafin, Linda G. Field Guide to the Rare Plants of Georgia. Athens: University of Georgia Press, 2007.  p. 390.
[ii] The information in this paragraph was gathered from the Symphyotrichum georgianum entry in NatureServe Explorer at [updated July 2011].

Friday, January 27, 2012

Living in a Bird House

A common wintertime sight from my office window.
Relocating to Atlanta, Georgia, I never imagined that I was moving to a place where I would routinely be awakened by birdsongs and calls.  While Atlanta is certainly urban it is also filled with mature trees, especially in old neighborhoods like mine.  My bedroom and office are on the second floor, which brings me closer to the tree canopy and to the birds and their many activities.

In fall and winter, I enjoy the luxury of leaving the door to the sleeping porch open at night.  My ideal sleeping conditions are fresh air, a cool head, and nest of warmth beneath a thick down comforter.  From this pinnacle of coziness, I have woken in the night to sounds of barred owls calling to one another.  Who-cooks-for-you, who-cooks-for-you-all?  And then the female’s response ending with an extended, gurgling vibrato you-allllllllll.  There is at least one very active pair in my neighborhood, and I have heard them during evening walks calling to one another as they move from tree to tree.  I’ve even seen them in flight, one following closely behind the other.  Sometimes I don’t even need an open window to hear the owls call, but when I do, I generally stop what I am doing and step outside to listen and maybe catch a glimpse of this affectionate pair.

In the springtime, there is no sleeping in.  One morning I woke up laughing because of the sheer cacophony of bird noises.  Here’s a list of the birds I am pretty sure I heard:
Cardinals: Very insistent, somewhat mechanical and certainly repetitive tik.  They have other songs, but they love this one.
Robins have a rich, fruity voice to my ear.  Very dignified.  But in the mornings they seem moved to a truly hilarious chortle. 
Phoebes position themselves on the peaks of our roof and call out their own names, FEE-bee, FEE-b-be-be.  Just beneath them, under the eaves, are the beams on which they build their nests.  In fact, although it’s winter I can see a mud and stick nest above my office window.  Phoebe’s reuse their nests, and come spring there will be a tail of the nesting mother sticking out from the nest, followed by the rasping noises of the babies when the harried parents approach with that moment’s meal.
Carolina Wrens:  Fussy, territorial and exceptionally LOUD.  That such decibels come out of this tiny bird is truly miraculous.  If you were trapped in a room with a Carolina wren, I imagine you would emerge with a severe headache and measurable hearing loss.  The wren’s songs are ubiquitous in my neighborhood: TEA-KETTLE! TEA-KETTLE! TEA-KETTLE!  And CHO-WE! CHO-WE CHO-WE!  Or, when feeling especially extravagant, the three syllable LIB-ER-TY! LIB-ER-TY! LIB-ER-TY!  Always in all-caps with exclamation points. 
More birds than this were surely involved in that morning’s riot, and I look forward to identifying more of my early-morning songsters this coming spring.
For now, I am enjoying the enormous flocks of Red-winged Blackbirds that visit the neighborhood.  Agelaius phoeniceus is the species' scientific name, Aeglaius being a Greek word meaning "flocking." They swoop in, black as holes torn in the sky, and bring with them their screechy chatter.  Suddenly its as if I live beneath an enormous swing set, making the sound of a thousand rusty swings. Sometimes I can catch a glimpse of a male's red and gold shoulder patch. 
Lots of birds around here flock in the winter, for the safety of a crowd and improved chances of finding food.  Robins do the same thing, and songbirds make up mixed flocks of chickadees, kinglets, nuthatches and titmice.[i]  They forage together and look out for predators, the latter being of no small consideration.  I’ve already mentioned owls, but lots other raptors live in the neighborhood: I have seen sharp shined hawks and red-tailed hawks, often with fresh-caught meals in their talons.  Jays and crows are also dangerous to small birds.  Peregrine falcons are said to nest in downtown Atlanta.  Really, it’s no surprise that the local sports teams are named after birds: the Hawks, the Falcons, and (until last year) the Thrashers are all hometown teams. 
The one birdsong I cannot abide is that of the Mourning Dove.  And lately a dove has been sitting in a tree near the house cooing its mournful oh-woe-woe-woe.  This doleful repetition depresses and enrages me.  I want to throw a boot at the bird and shout, For God’s sake, go away! Or I WILL GIVE YOU SOMETHING TO CRY ABOUT!  And should the day come that I unleash this outburst, the Carolina Wren will have nothing on me.

Kroodsma, Donald.  The Backyard Birdsong Guide (Eastern and Central North America).  Bellevue, Washington: Becker&mayer, 2008.

Parrish, John, et al.  Birds of Georgia. Auburn, Washington: Lone Pine Publishing, 2006.

Friday, January 20, 2012

The Death of Big Gulp

Sarracenia leucophylla blooming in the Conservation Gardens at the Atlanta Botanical Garden.
Sometimes as a volunteer at the Atlanta Botanical Garden, you’re given jobs to more or less get you out of the way.  I don’t begrudge this, especially on such a beautiful morning.  The potting benches inside were full, so my sister volunteers and I were assigned to work on the Sarracenia growing behind the greenhouses.  They had accumulated more than their portion of weeds and spent growth. Johnette, Jo Ann and I were on the job!  David Ruland also instructed us to be especially pitiless with pitcherplants showing signs of Exyra moth infestation.      
Jo Ann Bertrand and Johnette Brosewood at work behind the main greenhouses at the Atlanta Botanical Garden.
Pitcherplant Moths    Pitcherplant moths can do what no other insect can:  Walk both down and up the slippery walls inside the pitchers.[i]  Young moth caterpillars feed around the pitcher, girdling it so that it topples over. Older Exyra caterpillars weave a silk roof at the mouth of the pitcher.  Almost all the plants we worked on were white-top pitcherplants (Sarracenia leucophylla), so I believe we were encountering the effects of Exyra semicrocea. We saw doubled-over pitchers and also the drainage holes that the more mature caterpillars make to prevent flooding while they pupate.   Exyra ridingsii are only found in the yellow pitcherplant (Sarracenia flava), and Exyra fax colonizes just purple pitcherplants (Sarracenia purpurea).[ii]
Drainage hole likely made by Exyra catepillar.
Order from Chaos
There is something so satisfying about taking a pot that is full of weeds and spent growth and cleaning in up so that it contains only the desired plant species looking its best.  Here are some of the botanical makeovers we performed.
[If I could figure out how to put these before/after pics side-by-side I would.]
Johnette Brosewood is the most experienced volunteer when it comes to working with pitcherplants.  She shepherds them through every stage of life, and I am learning how to care for pitcherplants by working alongside Johnette and Jo Ann. And we have our work cut out for us with a greenhouse full of Sarracenia.  Sometimes I feel like a member of the paint crew on the Golden Gate Bridge:  Once we’ve dragged our brushes over the entire bridge, we cross and start all over again, only in our cases, repotting, weeding, top-dressing and pruning.
Conservation Greenhouse
Why does ABG have so many Sarracenia?   Pitcherplant habitat is some of the most endangered habit in Georgia (and elsewhere).  Pitcherplants grew throughout the Southeast, but land conversion into agricultural fields and residential and commercial developments, fire suppression, and invasive species have drastically cut their numbers.  In fact, in Georgia, pitcherplant bogs have been eradicated from the Piedmont and nearly eradicated from the Blue Ridge Mountains.[iii]
The Sarracenia in the Conservation Greenhouse are a living gene bank of plants grown from seed collected from pitcherplants in all the remaining mountain bogs.  Should something happen to the plants in the wild we have back up plants.  Meanwhile, ABG and its conservation partners (government agencies, academic and botanical institutions, and landowners) work to restore and maintain their natural habitat. 
The Death of Big Gulp One of the white-top pitcherplants stood out among the rest.  It was considerably larger and whiter than its peers, and the mouth of its pitcher formed a yawning maw.  Many of us had stepped out behind the greenhouse just to marvel at this specimen.  I named it Big Gulp.  At a certain point in our labors I looked for Big Gulp and didn’t see him (if I can give it a name, I can give it a gender).  
Big gulp, before the tragic event.
Alarmed, Johnette fished through the bin where we tossed our cuttings and found the decapitated Big Gulp.  She had seen the drainage hole and simply snipped not realizing she had cut down our mascot.  As a joke, I put a stick into the bottom half of the cut pitcher so that we could stake Big Gulp back on.  And I teased Johnette, calling her Black Thumbs.
Big Gulp had his revenge though.  His oversized-gullet was so full of decaying insect carcasses that once opened, he released a terrific smell. And a mass of red-eyed flesh flies descended on his remains.  
A chagrined Johnette

[i] Folkerts, Debbie.  “EPSN Science Fact: Insect and Pitcherplant Interactions.  Insect Profiles by Dr. Debbie Folkerts, Auburn University.”
[ii] Ibid.
[iii] Chafin, Linda G. Field Guide to the Rare Plants of Georgia. Athens: University of Georgia Press, 2007. P. 444.