Red River Gorge, KY

Red River Gorge, KY

Wednesday, October 22, 2014

The Tale of The Bluegrass Savanna-Woodland


Griffith Woods, Kentucky. Photo by J. Cox. Used without permission

The Inner Bluegrass region of Kentucky is an area well known for its gently rolling hills, fertile cropland, bourbon, and Thoroughbred horses. Much of the region is dominated by agriculture and horse pasture land, while Lexington continues to expand its borders into the surrounding landscape. That the region's native biological communities are no longer completely intact is a widely known fact. However, upon closer investigation, it becomes very difficult to say specifically what the local plant communities may have once looked like in the Bluegrass region.

It has been noted time and again that the prominent botanist E. Lucy Braun described the Bluegrass region as the "most anomalous vegetation area in the eastern United States." Many early explorers wrote short depictions of the vegetation that they experienced as they passed through the area. Several of these observations depict great herds of large ungulates, such as bison and elk, grazing on an understory comprised of wild ryes, running buffalo clover, and an abundance of cane found growing in open, park-like savanna-woodlands.
"There are many canebreaks so thick and tall that is is difficult to pass through them. Where no cane grows there is abundance of wild rye, clover, and buffalo grass, covering vast tracts of country, and affording excellent food for cattle. The fields are covered with abundance of wild herbage not common to other countries."
                    -John Filson, 1784. The Discovery, Settlement, and Present Site of Kentucke
“On the north-west and south-east sides of the Ohio, below the great Kanhaway river, at a little distance from it, are extensive natural meadows, or savannas. These meadows are from 20 to 50 miles in circuit. They have many beautiful groves of trees interspersed as if by art in them, and which serve as shelter for the innumerable herds of buffalo, deer, etc. with which they abound.” 
-Thomas Hutchins. 1778a. A Topographical Description of Virginia, Pennsylvania, Maryland, 
and North-Carolina.
“In all the fertile parts covered by the forests the soil is completely barren; no herbage is seen except a few plants, scattered here and there; and the trees are always far enough apart that a stag may be seen a hundred or a hundred and fifty fathoms off. Prior to the Europeans settling, the whole of this space, now bare, was covered with a species of the great articulated reed, called arundinaria macrosperma, or cane, which is in the woods from three to four inches [check units] diameter, and grows seven or eight feet high...”
-Francois Andre Michaux. 1805. Summarizing geography of central Kentucky

The concept of the Bluegrass savanna became widespread after gaining prominence through the research of Dr. Mary Wharton, professor of botany at Georgetown College. Dr. Wharton's work finds its basis in Lucy Braun's supposition that pre-European Inner Bluegrass forests could not have been dense, and were likely open and park-like. In an article published in the September 1980 issue of the  journal Castanea, William Bryant and Dr. Wharton along with William Martin and Johnnie Varner found blue ash, bur oak, Shumard oak, and chinquapin oaks in upward of 395 years in age. In particular, they note that the bur oaks are not known to be species of closed canopy forests, which suggests that the forests in the Bluegrass during the mid to late 1700's had relatively open canopies. These pre-European Bluegrass savanna-woodlands would have included a dense herbaceous understory comprising of cane, clover, and cool season grasses such as Elymus spp. They assert that open conditions could have been maintained by large herds of buffalo and other ungulates rather than fire. The loss of this natural disturbance coincides with the displacement of native grasses and forbs by Kentucky bluegrass and fescue around the time of the earliest intensive settlement of the area by Europeans. This viewpoint of the Bluegrass savanna-woodland is best captured by the 1991 book "Bluegrass Land and Life" by Wharton and Barbour. It is also very commonly found in the descriptions of the region found on state agency website such as the Kentucky State Nature Preserves Commission, and in books about Kentuckys biota, such at "Kentucky's Last Great Places" by the late Thomas G. Barnes.

In a 2008 article published in the Journal of Biogeography (PDF), Ryan McEwan and Brian McCarthy present data that calls into question the extent of the Bluegrass savanna prior to European settlement. Using dendrochronology, or the scientific method of dating trees by counting their annual growth rings, these researchers found evidence of very slow growth of these large "savanna indicator" species prior to European settlement. After European settlement, McEwan and McCarthy found that the rings in these savanna indicator trees are wider, perhaps as a result of tree removal by Europeans in the forests of the Bluegrass region which could have released the remnant "savanna" trees from competition for light and increasing their growth rate.  Indeed, the very notion of the savanna as a widespread component of the Bluegrass region of Kentucky is questioned by these results.

I have not been able to find any other more recent research on the topic, although Julian Campbell has compiled a great deal of research on his website, which can be found here.  It would appear that the issue of pre-European settlement vegetation in the Bluegrass region of Kentucky continues to be something of a controversy - an interesting one that is at the heart of conservation and restoration ecology, and one that bears much more discussion as well as more research!

Until next time!

JA

Friday, October 3, 2014

Pollinator Decline and Citizen Science - How Can I Help?


In BIO 1164: Biology and Human Concerns, we have been discussing the importance of conservation, and what one could do to help the environment given the dire condition of our planet's biodiversity. At times, I fear my students look at the state of the world and see no hope. What is a concerned, conscientious person to do? One option might be to become involved in a citizen science program!

During lab on Thursday, 2-Oct-14, my students participated in a pollinator count on campus at Transylvania University. TU is situated very close to downtown Lexington, KY. It seems imperative to understand how pollinators use any available resources in this urban setting. 

Transylvania University in Lexington KY. 
Though autumn is quickly approaching (low temperatures this weekend should approach the upper 30's!) goldenrod is still in bloom in the campus rain gardens. And, there are still pollinators out there!

A carpenter bee foraging on goldenrod
The students paired up, and took turns making pollinator visit counts on the goldenrod for five minutes at two spots on campus. One location was more centrally located and the flower garden was smaller, while the other was larger and on the edge of campus. I have two lab sections: one early, the other later in the morning. My students made predictions about whether they'd see more pollinator visits early or late, and in the middle of campus versus the edge. 

Then the pollinator visit counts began!


Above: Tim focuses on pollinator visits while Katie records data
Below: Joey and Teddy recorded their pollinator visits

As the students suspected, the late lab section saw greater pollinator activity than the morning group. Temperatures rose 17 degrees between the two lab sections. However, we anticipated greater activity on the edge of campus. Instead, we saw greater numbers of pollinators on the interior of campus. However, one thing we did not take into consideration was the composition of the pollinators across the two locations. In the campus interior, we saw greater numbers of small, solitary Halictid bees, whereas on the edge larger bodied bees such as honey bees and carpenter bees were dominant.

This was just one day of sampling, but as a pilot study it raises a number of questions. Which pollinators take advantage of the flowers on campus at Transylvania University throughout the year? How could the campus community more effectively use native flowers in our landscaping to benefit pollinators? Early next year, I hope to organize more pollinator counts on campus, in order to answer some of the questions raised by this short lab project.

If you would like to become involved in local pollinator counts, or would like to learn more about using native plants to enhance pollinators in your yard, there are lots of resources available for you! Check out the Xerces Society's bumblebee watch page, and take part in the search for bumblebees! The University of Kentucky has publications covering a range of topics  that might be of interest as well, such as landscaping with wildflowers, how to attract butterflies with native plants, and more. 

Finally, there is a smartphone app called iNaturalist which looks very interesting. This might be a great way to collaborate on a city-wide or regional pollinator study and share the results in real time. I plan to download and try this app out soon, and will post later about how it works!  

Knowledge, concern, and collaboration are key to effective conservation programs. Recently, there have been some indications that the hole in the ozone layer is beginning to shrink. This was a result of a massive, international collaborative effort to reduce CFC emissions. So long as concerned, knowledgeable people care about the environment, there is hope! 

Until next time!