Friday, June 17, 2016

Ramble Report June 16 2016



Today's Ramble was lead by guest leader Lauren Muller and Linda Chafin.
Here's the link to Don's Facebook album for today's Ramble. (All the photos in this post are compliments of Don.)
Today's post was written by Don Hunter and Dale Hoyt.

Twenty-four Ramblers turned out today.

Introduction to our guest leader: Lauren Muller graduated last year from UGA with a degree in Horticulture. She is currently a graduate student in the Horticulture department working with Dr. Jim Affolter, working on milkweed propagation. Lauren is also involved with the Prairie restoration effort in the power line right-of-way. She agreed to tell us about that project and her own research on milkweed propagation.

Today's reading: is from The World of Northern Evergreens, 2nd ed., 2011, Comstock Publ.; by E. C. Pielou.
[ Here is her Wikipedia entry: Evelyn Chrystalla Pielou (born February 20, 1924) is a statistical ecologist. . . . Pielou was the second woman to win the Eminent Ecologist Award (1986) from the Ecological Society of America. She has contributed significantly to the development of mathematical ecology, the mathematical modeling of natural systems and wrote six academic books on the subject. She now lives in Comox, British Columbia, Canada, and writes popular books on natural history. ]

Outdoor people have a wide spectrum of interests. Specialists tend to specialize in 'interesting' items: a birder is more likely to concentrate on owls than on starlings, and the average plant-hunter finds orchids more fascinating than crabgrass. Because of this preoccupation with the hard-to-find, the beautiful, and the unusual, most of the commonest objects in nature are apt to be ignored. They are simply there, part of the background. But to assume that because a thing is common it is therefore uninteresting is a mistake.
For most outdoor people the fact that they will encounter rank upon rank of coniferous trees in excursion after excursion in the future neither pleases nor displeases them. They don't even think about it. If there are innumerable coniferous trees in your future, why not take advantage of the fact, look at the trees more closely, and learn something about them? Knowledge cannot fail to bring interest and appreciation.
Learning to identify the different species of coniferous trees is only a beginning. Once you know the trees, many things can be observed if you know what to look for. There is however, a world of difference between seeing and interpreting. The ability to interpret is the hallmark of the true naturalist and developing that ability is one of the pleasures of being a naturalist. The well-informed naturalist understands and enjoys a thousand things that the uninformed one doesn't even notice; and the more people who understand and enjoy the woods, the more there will be to protect them.

Today's route: We hustled over to the power line right-of-way where Lauren told us about the prairie restoration project she is involved in. From there she showed us the propagation facilities at the Mimsie Lanier Center for Native Plant Conservation. Then we proceeded to the upper reaches of the power line ROW to see what was currently blooming. When it got hot we retreated back to the parking lot and Donderos' Kitchen.

Test plot at the Power Line ROW:
Lauren gave us an overview of the prairie restoration project. The phase currently in progress is to determine the best way to eliminate the non-native grasses from the future prairie. The project is funded by an Institute of Museum and Library Services grant.

[DH; Note: The following account is my paraphrase of Lauren's presentation. Any errors or misinterpretation are mine, not Lauren's.]

Ramblers look over the test plot while listening to Lauren
This future "Prairie on the Hill" is presently covered by a lawn of non-native grasses between the White trail and Lanier Center access road. The first problem in converting this area to a prairie is to determine the best way to 1) get rid of the existing grasses and 2) establish the appropriate native species of herbs and grasses. Last March a test area was sprayed with the herbicide glyphosate (Roundup) to kill the grasses (mostly Fescue, Bermuda grass and Crabgrass). In May Crabgrass was sprayed a second time. In the meantime Heather Alley, Conservation Botanist at the Mimsie Lanier Center for Native Plant Studies, has been growing "plugs" of native grasses and herbs to plant in the study plot this coming October.

The purpose of the test plot is to determine the most effective way to treat the area before planting it. Would simply planting the new material directly into the existing duff of dead grasses work? Or should the area be tilled first? Or would it be best to cover the area with black plastic or landscaping fabric and cut holes to insert the new plants? To decide the best strategy the test plot will be subdivided and each sub-plot subjected to one of the several different treatments. The best method of converting the entire lawn into a native Piedmont prairie will be determined by comparing the results from these different plots.

Questions for Lauren:

Why does fescue (and the other non-native grasses) out-compete the native grasses? 

1.   The three grasses grow vigorously and spread via rhizomes and stolons.
2.   They have a fast life cycle, rapidly growing from seed to mature, sexually reproducing plant.
3.   They create dense mats that exclude other plants.
4.   Fescue is evergreen so it can photosynthesize and grow during winter.

How long does glyphosate persist in the environment after it's applied? 

Glyphosate will completely degrade over a period of several weeks.  It's also really a fairly benign herbicide.

Lauren's research:

She is investigating the most efficient method for propagating and establishing Butterfly weed, the common orange flowered milkweed native to our area. She is using raised beds at the Atlanta Botanical Garden in Gainesville to test different methods of propagation there. She selected Butterfly weed because, of the species native to Georgia, its seed is the most readily available.

She will test her methods at two sites, one here at the State Botanical Garden (further up the hill in the more established areas of the prairie) and one at Panola Mountain. The Panola Mountain site has a well established prairie which has been the subject of many prescribed burns and has been planted with an assortment of native plants. 

Plantings will start this fall and continue at different times next year.  Her seedling plants are coming along nicely and she said volunteers to help in planting the plugs this fall would be appreciated.

She will compare establishment of milkweed in three different treatments: 1) inter-planting milkweed among existing vegetation, 2) mowing before planting (this eliminates above ground competion, but leaves the root systems intact) or 3) spraying the existing vegetation with glyphosate to eliminate both above and below ground competition.

Establishment success will be determined over the next year by measuring the general survival of the plants and using various growth metrics; e.g., height, flowering and general health.

Lauren has also grown about eleven different milkweed species, including Asclepias obovata, A. verticillata, A. tuberosa, A. incarnata, A. exaltata and A. michauxuii, in raised beds at the Gainesville Conservation Nursery. Her seed sources are from populations within a 50 mile radius so they are adapted to our local climatic/ecological conditions. She wants to grow these local eco-types to get more seed for the SBGG prairie restoration project, as well as to see how well these species will grow.

Milkweed biology:

How are milkweeds pollinated?
The structure that contains pollen and is carried from one flower to another is called the pollinium. It is shaped like a wishbone. Where the two parts join together is a sticky gland called the corpusculum. Two arms, called translators, extend from the corpusculum and at their ends each carries a sack of pollen grains. Collectively the bags of pollen are called pollinia. To clarify, if the pollinium is a wishbone, the ends you and your opponent grab when making a wish are the pollinia, the two bones that are connected at the top are the translators and the place where they are attached together is the corpusculum.
When an insect visits a milkweed flower if its leg slips down into a slit where the pollinium is the sticky corpusculum adheres to it. When the insect pulls free the pollinium is pulled out of the flower. Now the pollinator has the little wishbone of two pollen sacks glued to its leg. When it flies to the next flower (assume that it on a different plant) it will pollinate it only if it steps into a slit where the pollinia can be scraped off. The position of the pollinia has to change to accomplish this. After the pollinium gets glued to the leg it takes a couple of minutes for them to swing to the new position. This repositioning of the pollinia is done by the translators.
Complicated, isn't it!
If you examine a milkweed during the fruiting period you will see very few pods (fruit), indicating that very few of the flowers are successfully pollinated. But all it takes is one flower to be pollinated and the resulting fruit will contain hundreds of seeds, each one formed when one of the pollen grains in the pollinium reached one of the ovules in the flowers ovary.

After pollination do milkweeds face any other problems?

Other dangers threaten maturation of the seed. Milkweed bugs penetrate the fruits with their piercing-sucking mouthparts and drain the seeds of all their nutrients. Milkweed beetle adults and larvae feed on the leaves, depriving the developing seeds of the energy needed to mature. Oleander aphids (yellow or orange in color), another non-native species, attack the milkweed stems and suck the nutrients out of the plant, making more aphids rather than milkweed seeds.

With all these problems how can you establish a population of milkweeds?

If the individual plants are dispersed and not concentrated in a dense stand the risk of attack is diminished. Other plants, like dogbane, are attractive to milkweed bugs and can "spread the load" if planted some distance away.

Is milkweed a good nectar source?

Butterfly weed produces a lot of high quality nectar and attracts many potential pollinators: bees, wasps, beetles, ants and butterflies. In addition to its importance as a nectar source it, as well as other milkweed species, serves as the larval host plant of the Monarch butterfly and its relatives. Monarchs lay their eggs on milkweeds and the caterpillars cannot successfully feed on any other plant. [DH: Some sources claim that Milkvines (Matelea sp. and Gonoloba sp.) can support the growth of Monarch caterpillars while other sources state that this is not the case.]

Mimsie Lanier Center for Native Plant Studies:

The IMSL grant is also funding work on the floodplain restoration. Heather Alley, Conservation Horticulturalist is growing plugs of grasses for this effort.

Lauren pointed out that some years in the past a large mulching device was used in this area to eradicate Chinese privet. It churned up the land, grinding up everything in its path. In subsequent years the privet reappeared, either from the seed bank or from chopped up root pieces. These new plants were controlled by applications of glyphosate. The occasional new sprouts are controlled by spot spraying.

Lanier Center Gate:

[DH: In the fall of 2012 a flock of sheep were brought into this small area of the flood plain to browse down the privet. They were released inside the fence and corralled by a portable fence to keep them concentrated in the desired area. After several days the flock moved on. Some anecdotal reports indicate that some agricultural weeds were found in the grazed area, but determining their source is a problem. Sheep are ruminants, which means that they chew their cud. (As they graze the ingested plant material goes into the first chamber of the stomach where it is mixed with fluids and digestive enzymes. After some time this mass, now called "cud," is regurgitated and chewed further. Then it is swallowed and passes into the other parts of the stomach where it is further digested and the bulk of the fluid reabsorbed. The result is tiny pellets that are defecated. The double chewing that occurs reduces the likelihood of any seed surviving the transit through the gut. I've never heard any more comments on the effectiveness or ineffectiveness of the sheep in controlling the target plants in this area. I welcome comments – use the comment box at the end of this post to start a discussion.]

At the Green houses:

Ramblers view prairie plant propagation
First greenhouse contained plants that Heather is growing for a future native plant sale.

Second greenhouse contains plants that are designated for the prairie grassland project.  Included are, among others:  Eupatorium, bluestem grass, Purple love grass, Mountian mint and Bee balm.  Heather has been growing these since the spring and they will be ready to go out in the fall.

Butterfly weed; will any of these produce fruit?
We walked outside where some Butterfly weed is planted. Most of the flowers have dropped and the presence of firm, upturned stems will indicate that their flowers were pollinated and fruit will begin to form. Each flower can potentially give rise to a single fruit, but each plant may have as many as one hundred flowers, but only produce 1-3 fruits, if that many. Last year no fruits were produced by this group of plants.

Linda's discussion about invasiveness:

Linda was asked about invasive plants and I hope I've captured the essence of her reply. Rosemary mentioned that on the wildflower pilgrimage several of the leaders referred to Rhododendron as invasive. Someone else said that they heard that Live oaks were invasive in the coastal plain. Linda addressed the latter. The coastal plain ecosystem was dominated by the Longleaf pine-wiregrass association before the advent of European colonization. This ecosystem was maintained by frequent, low intensity fires caused by frequent lightning strikes. The Longleaf pine is fire adapted and can withstand such fires, but Live oak saplings are killed by them. So as long as fire is frequent it prevents the growth of fire-sensitive woody plants in the coastal plain. The pines are adapted to a landscape where fire is common. In the absence of fire woody plants can establish and their growth shades the understory, suppressing the growth of young pines. With the advent of colonial agriculture fire was suppressed setting the stage for the establishment of Live oak or other woody plants. In addition the leaves of Live oak are thick and leathery. When they fall they have curled edges making them like tiny shallow cups. These mini-cups can hold water and this impedes the spread of fire. Thus, when the oaks become established they can suppress the spread or intensity of fires. As Sue pointed out, this is an ecological process called succession. [DH; my two bits: We need to be careful using terms that are emotionally laden when we label natural processes. This is a good example. On the one hand a plant can be portrayed as "invading" the domain of another plant and displacing it. On the other they can be viewed as simply being part of a natural process (succession). We should recognize that the value attached to a process is really external to that process. Remember that the disappearance of the Longleaf pine ecosystem was not due to the spread of Live oak. It was because humans harvested the Longleaf and replaced them with faster growing species, cities and farms.]
Upper Powerline ROW:
All the plants we noticed are listed at the end of the blog.
Praying mantis egg case
Praying mantis egg case:
Attached to a stem at the edge of the path someone spotted the egg case of a Praying mantis. Last fall a female mantis finished eating her mate and deposited her eggs in a group surrounded by a spongy mass that has the texture of styrofoam packing peanuts. It is also covered with a secreted layer of a water resistant substance, so her eggs pass the winter dry and insulated from the weather. She then dies. About this time of year the eggs hatch and the babies, looking like tiny versions of their mother, struggle out of the case and wander off, looking for small insects to capture and eat. There will be 50 to 100 babies produced, depending on the size and health of their mother.
Carolina Milkvine flowers

Carolina Milkvine fruit
Carolina Milkvine:
In the prairie to the west of the path we discovered a Carolina Milkvine with both flowers and a fruit. Milkvines are related to Milkweeds. Their shared name comes from the fact that most species exude the same milky, latex containing, fluid from cut stems or leaves. Carolina Milkvine has flowers that are entirely dark maroon and a fruit that is spiny or warty. Another species of Milkvine in found in our area, but we didn't see it today.
Carolina Horse-Nettle; note the cluster of yellow anthers 
Carolina Horse-Nettle and buzz pollination:
The flower of this plant resembles that of a tomato plant, or, for that matter, other members of the Nightshade family. It has long, yellow anthers that closely surround the central pistil of the flower. In addition the anthers open at the pointed end, instead of splitting open as in many other plants. The pollen inside the anthers is dry and dust-like; many other insect-pollinated plants have large, sticky pollen grains. These feature are seen in plants that rely on pollinators that can perform "buzz" pollination, typically bumblebees. In buzz pollination the bee grasps the flower and vibrates its flight muscles without moving its wings. When it does this it emits a buzzing sound that gives the process its name. That vibration is transmitted to the flower and the pollen is shaken out of the anthers. So how does the dust-like pollen get on the bee? When a bee flies through the air it acquires a charge of static electricity and the dry, dust-like pollen is attracted to the hairy body of the bee. Some of our important crops rely on buzz pollinating bees, blueberries being one of them. In locations where blueberries are produced in greenhouses growers find that more berries are produced if bee colonies are placed inside the greenhouse. Not honeybee colonies – colonies of other types of bees, because honeybees cannot buzz pollinate.

Other flowers seen:
Wild Bergamot 

Carolina Desert Chickory

Queen Annes' lace

Sensitive Brier

Wild Petunia

 

SUMMARY OF OBSERVED SPECIES:

Common Name
Scientific name
Power line ROW test plot
Crab grass
Digitaria sanquinalis
Tall fescue
Festuca arundinacea
Bermuda grass
Cynodon dactylon
Mimsie Lanier Center
Butterfly weed
Asclepias tuberosa
Virginia buttonweed
Diodia virginiana
Elaine Nash Prairie
Carolina desert chicory
Pyrrhopappus carolinianus
Queen Anne's lace
Daucus carota
Sensitive brier
Mimosa microphylla
Mountain mint
Pycnanthemum incanum
Bee balm
Monarda fistulosa
Praying mantis egg case
Insecta: Mantodea
Mockernut hickory
Carya tomentosa
Carolina milkvine
Matelea carolinensis
Carolina horsenettle
Solanum carolinense
Wild petunia
Ruellia caroliniensis



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