Friday, May 31, 2013

The Girls are in Bloom (too)

Admiring the opposite sex.
Quaking aspen don't get much attention these days.  Most people are gawking at and raving about brightly-colored spring wildflowers, especially the pasque flowers, while the aspen trees remain leafless, just standing there, seemingly doing nothing.
Quaking aspen, Populus tremuloides.
But looks are deceiving of course.  In reality their growing season is already well underway ... just look at the trunks.  Aspen are famous for smooth white bark, but in this stand it’s more of a pale green, especially on younger trees.  The bark contains chlorophyll, for converting sunlight to energy, and these trees are photosynthesizing even without leaves. In fact, the green bark may out-produce the leaves until well into the growing season (Pearson 1958).
Green aspen bark may to be more common where growing seasons are shorter (Pearson 1958). 
Not only are the aspen photosynthesizing, they’re in full bloom!  Few notice because the flowers are so small and drab ... though in the right light, they can be quite lovely.
Backlit male catkins (flower clusters).
Aspen are dioecious, i.e. male and female flowers are found on separate individuals.  Moreover, aspen readily spread by vegetative propagation (root sprouts), so an entire stand may be a single individual and all trees will be the same sex.  Until last week, all stands I had hiked through were male. 

Male aspen flowers are reduced, incomplete and imperfect ... but hardly inadequate!  They should be admired for their elegant efficiency.  They have just what it takes to produce pollen and cast it to the wind.  [reduced = tiny; incomplete = missing parts; imperfect = unisexual]
A male aspen flower is just a disc with stamens; hairy floral bract on right.  From FNA.
Male quaking aspen were featured in a previous post, The Boys are in Bloom. The only reason I didn't include female trees was that I hadn't seen any.  Now finally I have.
Female quaking aspen in full bloom.
The female flowers are showier than the males.  They're green for one thing, and bigger, especially as the ovaries ripen.
Female catkin with green flowers and brown fringed floral bracts;  ca 1 in long.  Photo courtesy dgm.
A female flower consists of a pistil perched on a cup-shaped disc.  The plump ovary is topped by a brown 2-lobed stigma, ready to receive pollen (click on photo above).  Below, pistil in cup-shaped disc on left; capsule on right has split to release seeds; from FNA.
With time, the ripening ovaries swell and the stigmas wither.  At maturity, each ovary becomes a capsule containing seeds topped with fine hairs.  Eventually the capsules will split, and the seeds will take to the wind.  In the photo above, suture lines are visible on some of the young capsules.  Note fringed floral bracts and remains of brown stigmas.

Why has it taken so long to find female trees?  Are they less common?  I can’t say as I haven’t sampled sufficiently (should hike more, work less).  Do females bloom later?  I don’t think so -- I saw both male and female catkins on my hike last week.  The males were drooping, looking tired and spent.  The females were fully elongated, with plump green capsules.  The flowering season was coming to an end.
I kept on through the shady grove.  It was chilly and I was thinking about turning around when suddenly I was surrounded by trees glowing in the sunshine.  They were starting to leaf out.  Young aspen leaves are yellow-green -- not nearly as showy as the brilliant gold and orange ones of fall, but gorgeous enough when backlit!

Literature Cited

Pearson, LC and Lawrence, DB.  1958.  Photosynthesis in aspen bark.  American Journal of Botany 45:383-387.

Tuesday, May 28, 2013

Good Morning, Good Morning!

Last week as I was walking along a trail through pines and aspen, looking at patterns of light and shade, I was suddenly halted in my tracks by a radiant cluster of pasque flowers, all glowing in the morning sunshine.  “Good morning, good morning!” they called sweetly.
You doubt me?  I assure you this is what I heard, though I had to listen very carefully because pasque flowers are shy -- that’s why they often turn their heads and always whisper.  But once upon a time, long ago, things were different ...
“In the long ago, whenever any of the people happened to pass by where these flowers were blooming they tried to show the friendliness which they felt for human beings by nodding their heads in the chilly spring wind, showing their smiling faces and saying, “Good morning! Good morning!”  But the people passed them unheeding.  They became abashed at this indifference, so nowadays still feeling friendly towards the people in spite of such rebuffs, they bashfully turn their heads to one side as they nod and call their kindly greetings in their sweet low voice.”  (Dakota story, from Gilmore 1922)
Just starting to bloom, these pasque flowers bashfully turn their heads.
How anyone could walk by pasque flowers "unheeding" is beyond me.  In fact most Wyoming folks are thrilled to find them -- they bring us great joy!  They're among the first plants to bloom in spring (May in the mountains), along with Easter daisies and sagebrush buttercups.  Even better, pasque flowers are large and showy.  Some of the plants I saw were a good six inches tall.  How do they manage to grow so quickly so early in the season?
Easter daisies stay small and low-to-the-ground, even when flowering.  Coin ca 0.5 in across.
A pasque flower in full bloom hardly seems shy.  Purple sepals ca 1 in long.
The pasque flower’s trick is to form buds the previous fall, buds covered with silky hairs that help keep them warm.  The downy coats are the source of another common name -- goslinweed.  Several emerging goslings are visible at the base of the plant above.

Pasque flower, goslinweed, prairie crocus, pulsatille, hokshi-chekpa wahcha (Dakota for twin flower) and prairie smoke (more commonly used for Geum triflorum) all are names for this plant.  In school we’re taught that scientific names, though constructed from a dead language (Latin), are what we should use because they don’t have the ambiguity and confusion associated with common names.  This is not the case with the pasque flower however.  The experts remain divided.  Some call it Pulsatilla patens, others Anemone patens, and a few try to maintain the original Pulsatilla ludoviciana, though declared invalid years ago.  In any case, the pasque flower is a member of the Ranunculaceae (buttercup family) and is closely related to anemones, if not actually one itself.
Six-to-eight petal-like sepals surround numerous stamens, with numerous pistils at the very center.
Though showy, pasque flowers are but a brief flash of color in the spring sunshine.  They soon drop their sepals, and the pistils mature into seed-bearing achenes with long tails.  This is when the leaves really get going.  Most vegetative growth occurs after flowering, and leaves are present through much of the growing season, converting sunshine to energy and finally to buds (goslings) for next year.
The Pasque Flower [source no longer available; March 2016]
When Melvin Gilmore was studying the ethnobotany of Great Plains tribes in the early 1900s (see Note below), he came across another charming story about the pasque flower.  Later in the spring, when many flowers are in bloom and brightly decorated with colorful petals, the pasque flower has already gone to seed.  So it sings a song to the other flowers, hoping to share its wisdom:

“I wish to encourage the children
Of other flower nations now appearing
All over all the face of the earth;
So while they awaken from sleeping
And come up from the heart of the earth
I am standing here old and gray-headed.”

(translated from the Dakota language by A. McG. Beede; in Gilmore 1919)
It's still early spring but already seeds are ripe, each topped by a long feathery tail.

Note:  In the early 1900s, Melvin R. Gilmore interviewed elderly Plains Indians who had once gathered native plants and still knew the old names and uses.  He was determined to gather this knowledge ...
"while it may still be obtained, before the death of all the old people who alone possess it ... The old people themselves appreciate this and have expressed themselves as glad to give me all the information they could in the matters of my inquiry, in order that, as they said, future generations of their own people as well as the white people may know and understand their manner of life."
Gilmore first reported his findings as a PhD dissertation at the University of Nebraska (1914).  In 1919, it was published by the Bureau of American Ethnology.  Several years later he wrote Prairie Smoke, a wonderful compilation of Plains Indian stories and legends.

Sources (and recommended reading!)

Gilmore, M.R.  1919.  Use of plants by the Indians of the Missouri River region.  Bureau of American Ethnology.

Gilmore, M.R.  1922.  Prairie smoke, a collection of lore of the prairies (2nd ed., revised). Bismark, ND.  Available online at the Project Gutenberg.

Ode, D.J.  2006.  Dakota flora, a seasonal sampler.  Pierre:  SD State Historical Society Press.

Friday, May 24, 2013

Easter Daisy Rescue

Between Laramie, Wyoming’s West Side and Interstate Highway 80 is a zone of undeveloped open space along the Laramie River.  This is an under-appreciated natural area -- a mix of riparian habitat, small wetlands, grassland and light industry.  All it takes is a bit of careful attention to discover treasures -- plants in bloom, animals doing their thing (foxes, muskrats, skunks, mice, deer, beaver, frogs, herons, kingfishers, hawks, ducks, orioles, goldfinches ... etc.), and the antics of the river (freeze, thaw, rise, drop, sparkle in the sunshine).
Wetland in winter -- cattails are on display all year round. 
Laramie River ice art, courtesy Jack Frost.
They may be small, but in early spring the Easter daisies are spectacular and make everyone smile!
Then every very four or five years, something gets built and the open space shrinks.  The largest area of grassland was split in half recently, when McCue Street was extended.  A Greenbelt Park was put in along the river, with a paved path -- great addition for Laramie citizens, but maybe not so great for wildlife in the riparian zone.  The land around the Territorial Prison was fenced, and we were told that anyone caught on the property without a pass would be arrested.  (Time would be served in the County Jail ... the Territorial Prison is a tourist attraction.)
Recent additions to the Territorial Prison.
The latest project in the works is a street that will connect the new viaduct across the Union Pacific Railroad tracks with Highways 130 and 230.  The route will cross the open space just west of the neighborhood, where I frequently walk.  There is quite a nice patch of Easter daisies (Townsendia sp.) directly in the path of the new street.  Can anything be done????
The “Blue Route” was chosen after much debate (not about Easter daisies).
Yes! ... call the Easter Daisy Rescue Team!!  Actually, I’m the entire “team” but I did seek help.  I emailed Cindy, long-time president of the Great Plains Native Plant Society and native plants gardener par excellence.
“There's a nice patch of townsendias in the open space west of my house that are due for destruction (street).  I'm thinking about snagging some for one of my wildflower beds.  Have you tried them?  Any suggestions?”
Her response was enthusiastic and very helpful:
“I think a good time would be just after they go to seed.  That would give them some time to recover from the stress of bringing all those buds to bloom, and yet still take advantage of the spring flush.  I get the best results when I can dig a good-sized clump of soil with the plant, rush it to its new home, and plop it into a hole of the same size.  Plastic grocery sacks make good transporters.  You won't even have to give them a sip out of your water bottle to tide them over during the trip to their new home! ... If there are plenty, why not dig some now, and some later?”
I proceeded exactly as directed.
By May 12, the threatened Easter daisies were almost done flowering.  Most of the heads had turned pink, and were closed up tight.
I dug up clumps -- plants with large chunks of soil -- put them in plastic grocery sacks and headed home.  There I dug appropriately-sized holes and "plopped" them in.
Easter daisies in their new home.
The transplanted Townsendias are doing well.  The leaves are all still vigorous and standing upright, not lying withered on the ground.  Last week, the heads opened once again, this time revealing little balls of winged seeds -- tiny “clocks” (as dandelion seed heads are called).  It was time for the second phase of the project.
Easter daisy clocks, ready for seed dispersal.
In exchange for Cindy’s helpful information, I was to collect seed for the Great Plains Native Plant Society’s seed exchange.  So I headed back to the Easter daisy patch where there were abundant seed heads.  Being a well-trained field botanist, I collected a voucher specimen to document the species, variety, genetic strain ... whatever ... of the seed source.  Easter daisies can be difficult to tell apart, so this voucher will be critical for determining which Townsendia this is, as will be seen in the sequel to this post.
Collecting tools.  A brick hammer is the best thing for getting a plant and its root out of tough prairie soils.  The specimen (near hammer head) with extra seed heads (left of hammer) go in the plastic bag.
Townsendia clocks, destined for the Great Plains Native Plant Society seed exchange.
At home, the specimen is cleaned of dirt and other debris ...
... revealing multiple stems in a single cushion.
This "cushion plant" is much too thick to press flat, so it is split, through the root.
Some heads are pulled off and pressed to reveal characters needed for identification.
Loose seeds are included.  They will go in a fragment envelope as part of the herbarium specimen.
The specimen in newspaper is placed between sheets of corrugated cardboard in the plant press ...
... and strapped up tight.  It was a sunny day, so I put the press on the dashboard of my parked car for drying.
And finally -- data, of course.  The necessary information was entered in my field book, including legal description following the old system still in place, and GPS coordinates for the inevitable change ahead.
My first collection of 2013.

Wednesday, May 22, 2013

The Record Keeper

Several weeks ago I posted a geo-challenge, What do these deposits have in common?, with photos of four diverse accumulations of organic matter:  a mass of amber-like gunk containing stems and seeds, a pile of leaves and twigs, more amber-ish gunk plastered on the wall of a rock crevice, and sticks and pieces of cow manure in a rock cavity.

And the answer is (~fanfare~) ... this guy (or one like him).
Each was deposited by a packrat (Neotoma sp.), also called woodrat.  Above, bushy-tailed woodrat at Chaco Canyon, New Mexico.  Courtesy USGS and NOAA.

Packrats are not true (Old World) rats, as are the infamous rats of urban ecosystems (Rattus rattus and R. norvegicus).  Rather they are members of the Cricetidae family, along with other New World mice and rats, for example deer mice, voles, lemmings and muskrats.  Packrats weigh in at 100-600 g (i.e. up to a pound), and have long tails, prominent ears and eyes, and strong feet for climbing trees and rocks (and rafters in the attic).  Twenty-one species inhabit North America, from Canada close to the Arctic Circle south to Nicaragua.  They live in diverse habitats -- boreal forests, tropical forests, chaparral, lava fields, alpine tundra, deserts of various kinds, and the nooks and crannies of human habitation.

In all environments, packrats depend on moist plant matter for both food and water, and so spend a lot of time foraging.  They have a strong propensity to collect non-food items as well, hence their name.  Collectibles in the mind of a packrat include plant fragments, bones, dung and a wide variety of "interesting" items, especially anything shiny.
Packrat den with nest found under outdoor grill.  Note pieces of aluminum foil.
It’s the packrat’s curious house-building that is of interest to us.  They construct dens in various styles, depending on the species, utilizing structures and materials available in their particular habitat.  For example in the chaparral of coastal California, the dusky-footed woodrat (Neotoma fuscipes) builds large mound-like dens of leaves, twigs and other debris (photo below) that provide protection from rain and predators, and insulation against temperature extremes.  Inside, the den is subdivided into chambers, including one for a nest, several pantries, and one on the periphery or just outside that serves as an outhouse and garbage dump -- a midden.  As we'll see shortly, some packrat middens are of great interest to humans.

Below, a dusky-footed woodrat den at the base of a sprawling coastal live oak, Montaña de Oro State Park, California.  For an entertaining tour of dusky-footed woodrat dens, including interior shots, see Living in the Sticks at nature of a man.
In areas with rock outcrops, packrats take advantage of natural structures and construct dens in crevices and cavities, requiring less effort and resources.  Plant fragments, bones and the usual collectibles are added.  Large mammal dung is popular in some places.
A packrat lined this rock cavity with sticks and pieces of cowpies (the Honeycombs in western Utah).
The middens of rock-outcrop-dwelling packrats, especially in arid environments, are the ones we value most.  Some are spectacular.  Protected from the elements deep in a crevice or cavity, large masses of packrat debris can accumulate, cemented together with highly-concentrated urine to form a hard, durable amber-like material called amberat (or occasionally "ratite").  In such a situation a packrat’s refuse pile may remain undisturbed for thousands of years, growing with each generation of residents.  The giant midden below is at least 28,000 years old (orange notebook is 7” x 4”).  Courtesy USGS.
Lovely golden amberat covers a crevice wall in volcanic tuff; Hickison Summit, central Nevada.
As you can see above, amberat can be beautiful ... and maybe even appealing:
"we came to a high cliff and in its face were niches or cavities as large as a barrel or larger, and in some of them, we found balls of a glistening substance looking like pieces of variegated candy stuck together ... It was evidently food of some sort, and we found it sweet but sickish, and those who were hungry ... making a good meal of it, were a little troubled with nausea afterwards" (party of Gold Rush miners headed for California in 1849, from Betancourt et al. 1990, p 3).
Amberat may be a terrible food substitute, but it’s invaluable nonetheless, for it contains a record kept by all packrats that ever lived in the den.  Plant fragments are well-preserved in amberat, and can be identified even after many thousands of years (photo below).  In the dry environs common in the American West, middens are a major source of evidence for reconstructing past vegetation and environments, from the Pleistocene (last glacial advance) through the Holocene (post-glacial time through the present).  Some middens have been found dating to at least 40,000 years before present.
A mummified 12,500-year-old snakeweed flower from a packrat midden is easy to identify.  Source.
Fossil middens, with the collections of many many many generations of packrats from prehistoric times to the present, allow us to look back on the vegetation of yesteryear and the way it has changed over time.  The Colorado Plateau is especially amenable to such paleoecological reconstruction.  In the arid environs of the Plateau, many fossil middens have been preserved.  The Plateau also is an area of high topographic relief, where vegetation can shift up and down in elevation in response to climatic change.  Vegetation and climate change from glacial times to the present have received a lot of attention.
Diagram courtesy USGS and NOAA (click on illustration for larger view).
During the last glacial period, boreal and montane forests were common on the Colorado Plateau.  Now these trees are restricted to montane sites, having moved up in elevation as much as 3000 feet (diagram above).  In other cases, plants responded by shifting their distribution along a north-south gradient.  For example, the piñon-juniper woodlands that are so common on the Colorado Plateau today were absent during the last glacial period, when they grew much further south.  They invaded northward as the climate warmed.
Modern-day piñon-juniper woodland; San Rafael Swell in central Utah. 
Interpreting a packrat’s record requires caution and a good understanding of the critter itself.  Though a great collector, a packrat’s foraging range is limited to within 30-100 m of its den.  And they can be picky, especially those that are dietary specialists.  For example, Stephen’s woodrat eats little aside from juniper, while a bushy-tailed woodrat living in the same area will have a much more diverse diet.  All packrats prefer moist plant parts (at least 50%  water by weight) as food is pretty much their only source of water.

Thus a packrat’s tastes distort the relationship between the record kept in its midden and the surrounding vegetation.  While middens may reveal some of the plant species that grew in the area, we can’t easily conclude that there weren’t others as well, even some that were common.  Perhaps the packrat just wasn’t interested (which seems to be the case for grasses, for example).
The bushy-tailed woodrat (Neotoma cinerea) is not a picky eater, and so its midden is a better indicator of the surrounding vegetation.  Photo courtesy MT Fish, Wildlife & Parks.
The abundance of a given plant species in a midden does not necessarily reflect its abundance in the surrounding area.  Trees are especially prone to over-representation because it’s not uncommon for trees to grow adjacent to rock outcrops in areas otherwise tree-less (more water, shade available).

Another confounding factor is change-in-ownership.  One can’t assume that the same species of packrat has occupied a den for thousands of years, especially if the climate changed during that time.  Indeed, some investigators found that when they removed a packrat from a den and a different species moved in, the new midden deposits changed noticeably ... due to change in packrat tastes rather than in the surrounding vegetation.

In spite of these complications, middens continue to be valuable indicators of paleovegetation, especially when multiple middens are used, and in conjunction with pollen data.  Fossil middens and fossil pollen provide complementary information.  Plant fragments from middens generally can be identified to species, but represent just the vegetation close to the den.  Pollen records come from larger areas, but most source plants can’t be identified beyond genus or even family.

The Pleistocene - Holocene transition is the most popular focus of midden study, but recent changes in vegetation also have been clarified using records kept by packrats, for example the contentious topic of whether juniper invasion has been facilitated by recent livestock grazing and fire suppression.  In the Pacific Northwest, midden data from lava tubes, combined with pollen analyses, indicate this trend is related to post-glacial warming, having begun long before humans, cattle and sheep arrived (Mehringer and Wigand, in Betancourt et al. 1990).
Piñon-juniper woodland possibly invading sagebrush.  For more detail, see Utah's Rangelands.
Cole et al. (1997) used midden data to look at historical changes in high-desert vegetation in Capitol Reef National Park.  Presettlement middens consistently contained a suite of palatable (to livestock) plant species that are now absent or greatly reduced, for example winterfat and Indian ricegrass.  Unpalatable species now present, such as snakeweed and Russian thistle, were not found in middens older than 200 years.  The authors concluded that “the most severe vegetation changes of the last 5400 years occurred during the past 200 years”, i.e. with introduction of livestock grazing.
Known packrat midden sites in western North America; last updated 05/20/2013; courtesy USGS.
Packrat middens are so common in the deserts of the American West that it seems all one has to do to find one is peek into enough crevices and cavities.  They are worth seeking out.  Amberat is distinctive and curious, and even beautiful in some cases.  If you're lucky, a midden will be close enough to the ground to examine its contents.
Stems and seeds preserved in amberat in a crevice in the Sevier River Formation, southern Utah.
Attentive readers will remember that amberat is not edible.  However there are claims (mainly by vendors) that it possesses healing properties due to “a unique complex of bioactive substances” (of course!).  But before you start scraping amberat off rock walls and ledges, you might want to read this recent post at The Eekosphere.
The beloved Eek.  Photo by T. Walsh, 2013; from The Eekosphere.
P.S.  While I was putting together this post, I happily stumbled upon The Eekosphere, a great blog about Eek, a dusky-footed woodrat (packrat) whose best friend is Scribble, a Norwegian rat.  No, this is not a children's book ... it's a true story! ... and highly-recommended.

Sources (in addition to links in post).

Betancourt, J.L., Van Devender, T.R., and Martin, P.S.  1990.  Packrat middens.  The last 40,000 years of biotic change.  Tucson:  Univ AZ Press.

Cole, K.L., Henderson, N., and Shafer, D.S.  1997.  Holocene vegetation and historic grazing impacts at Capitol Reef National Park reconstructed using packrat middens.  Great Basin Naturalist 57:315-326.

US Geological Survey in cooperation with Northern Arizona University.  2008.  Prehistoric Packrats Piled Up Clues to Climate Change (PDF).

USGS and NOAA.  Paleo Slide Set: Packrat Middens: Vegetation & Climate Variability in the Southwestern United States.  Last modified 12 October 2001.