Red River Gorge, KY

Red River Gorge, KY

Wednesday, September 24, 2014

Invasives and Natives - Emerald Ash Borer and Blue Ash

Last week I posted an introduction to the emerald ash borer (EAB: Agrilus planipennis), an exotic invasive wood-boring beetle that since 2002 has been spreading throughout the landscape of the eastern United States and Canada. As the name implies, EAB targets ash trees (genus Fraxinus) and infestations can lead to tree mortality very quickly.

Ash trees are important components of urban and suburban ecosystems, as they are very popular street trees. In central Kentucky, however, one species of ash represents much more than the ash trees used for ornamental landscaping. Blue ash (Fraxinus quadrangulata) is a major component of woodlands in the Bluegrass region. These large, impressive trees have narrow range restrictions, and are most often found in association with limestone-based soils, such as those found in the Bluegrass. This species, along with chinquapin oak (Quercus muehlenbergii), is indicative of an anomalous (and controversial!) vegetative community, the Bluegrass savanna-woodland. (Note: I hope to spend some time discussing that controversy sometime soon! Was the Inner Bluegrass made up of savanna-woodlands with sparse tree canopy cover and understories comprised of cane and clover? The answer is tricky, and none too clear!)

Blue ash and chinquapin oaks at Griffith Woods WMA, near Cynthiana, KY. Photo by Neil Pederson
Regardless of the precise pre-European vegetative composition of the Inner Bluegrass, these large, ancient (many date to the late 1600's/early 1700's!) blue ash trees are irreplaceable components of Kentucky's native biota. The emerald ash borer represents a dire challenge to the fitness of these stately trees, and a threat to overall biodiversity. What can you do to help? Next time, I plan to discuss ways in which interested naturalists and citizen scientists can play a huge role in the fight to preserve native ash trees and monitor the spread of EAB.

We are starting to discuss plants in more detail in BIO 1164: Biology and Human Concerns. On Thursday, 9/25/2014 we'll have lab outside, and we'll begin learning to identify some trees common to our region. There are many examples of native trees on campus at Transylvania University, so we'll have plenty of specimens to practice with! Beyond learning some tree ID skills, I hope that my students will become familiar with the ins and outs of using dichotomous keys. That's an important skill for any naturalist to have, one that will make identifying other groups such as birds or insects much easier for them!

Until next time!

JA

Tuesday, September 16, 2014

Backyard Ragnarök: The Emerald Ash Borer

Naturalists of all ages know that trees are cornerstones of the environment. Trees provide food and habitat for wildlife, play a major role in global oxygen and carbon cycles, help to stabilize soils and prevent erosion, and perform many other ecological tasks.

"The Ash Yggdrasil" (1886) by Friedrich Wilhelm Heine
Trees can also hold great emotional, aesthetic, and cultural value. From the ancient Babylonian and Greek societies to Native American tribes, many cultures revere trees to some extent. Trees were central in many tales of the Norse. According to the Prose Edda compiled by Snorri Sturluson, the nine worlds were held within the boughs of Yggdrasil, the World Tree. Yggdrasil was a giant ash tree where the gods held court. This immense, cosmic tree was a link that served as connective tissue for the Norse cosmology. Although the fate of Yggdrasil after Ragnarök, the Norse end-times, is never explicitly stated it is surmised that the survival of humankind rests solely upon this gigantic tree1.


I find this legend especially interesting given the serious threat that native ash trees face throughout the eastern United States. An exotic invasive insect called the emerald ash borer (Agrilus planipennis) has been rapidly dispersing throughout the eastern and midwestern United States, aggressively attacking native ash (Fraxinus) species. As adults, these beetles are metallic green, and feed on ash foliage. They do most of their damage as larvae, burrowing through the vascular tissue and disrupting the tree's ability to transfer food downward from the leaves.


Top: Emerald ash borer larva.
Bottom: Emerald ash borer adult.
Images from Bugwood.org

There are confirmed populations of emerald ash borer in Kentucky, and according to the Kentucky Division of Forestry, there are approximately 130 million individual ash trees in the Commonwealth. How might this invasion affect Kentucky? Native ash trees support a number of native insect species, mostly Lepidopterans (butterflies & moths) which subsist on ash foliage as caterpillars2.  Localized mortality of native ash trees in forests can cause canopy gaps to open, changing light levels within those forests, leading to increased temperature and reduced moisture on the forest floor. This can affect the composition of the forest floor plant community. One ash species, the blue ash (Fraxinus quadrangulata) is a tree indicative of a functionally extinct ecotype found only in Kentucky - the Bluegrass Savanna. The emerald ash borer invasion leads to an overall net reduction in biodiversity in our forests.

From an economic standpoint, Louisville Slugger baseball bats are made from northern white ash grown in Pennsylvania. Emerald ash borer is moving closer to these trees, and the company is evaluating other woods to use for bat production. Ash is also a popular urban tree in Kentucky, and is planted in neighborhoods and along roadsides to improve local aesthetics. Loss of these trees and the associated cost of removal represents an economic loss as well.

Recently, we have been discussing the importance of biodiversity in BIO 1164: Biology & Human Concerns. The threat that invasive species pose to native biota is alarming, and I will explore this topic in more detail later. But for now, let's return to our Norse myth. Each native species, from plants to insects to vertebrates, could each be represented by a branch on the World Tree, Yggdrasil. Since human society cannot be separated from nature, do we have an obligation to protect and conserve biodiversity to ensure a higher quality of life for future generations? If so, the parallel of the old Norse myth is an effective one, and it is in our best interest to protect Yggdrasil, or biodiversity, and stave off ecological Ragnarök for as long as we can!

For more information on emerald ash borer in Kentucky visit http://pest.ca.uky.edu/EXT/EAB/welcomeeab.html

Until next time!

JA

1. Larrington, Carolyne (Translator) (1999). The Poetic Edda. Oxford World's Classics. ISBN 0-19-283946-2
2. Wagner DL. 2007. Emerald ash borer threatens ash-feeding Lepidoptera. News Lepid Soc 49:10–11

Tuesday, September 9, 2014

What is Nature?

A recent topic we've been discussing in BIO 1164 is the idea of the place and role of humans in the scope of nature. What do we think of when we think of nature? Large tracts of unbroken forest, streams, and meadows? Hilltops and hollows, and ancient gorges carved into the rock by the wind and rain over millions of years? Certainly no one would argue with those descriptions.

Pine Mountain, Pineville, KY
Is there a problem with referring to nature as a place removed? Is nature a destination to which you need to pack up the car and travel, burning fuel on your way to enjoy a day hike? What does this separation signify about how we view our place in the world? Clearly, each of us lives within an ecosystem. If you open the door, no matter where you are, you can observe plant and animal species along with sunlight, soil, and water. It may be that you live in an urban area, with parks scattered around the city. On the other hand, you might live in a rural area and an idealize view of nature isn't far from you. Regardless, a view of nature that does not include humans and the large influence that we have on our environment is rather incomplete. Wendell Berry writes in the foreword to our textbook, "Kentucky's Natural Heritage" about the value of  knowing and observing local biota. This knowledge can tell us much about the health of the local environment that we all share. These are ideas that my students and I will develop and explore throughout the semester.

What is a naturalist? The role of the naturalist has changed throughout history, from ancient Greek philosophers to wealthy Victorian era plant and animal collectors and enthusiasts. We are discussing the history of natural history, and the interesting ways in which the field has been intertwined with philosophy, faith, and the arts. We have also been discussing what it means to be a naturalist, and the contributions that naturalists have made to science throughout history. Of course, the focus has been on Darwin, but soon we will delve into the writings of other important figures like John Muir, Aldo Leopold, and Rachel Carson. But, more importantly, we'll be spending some time outside on campus at Transylvania University, sharpening our plant and insect identification skills (= the fun stuff!)

Until next time!

Monday, September 1, 2014

It's a Brand New Semester!

Hello, I'm Josh, and I'm an entomologist.

Let's start over.

I'm Josh, and I'm a Kentuckian. I speak for the trees. I have interests which are wide and varied, but one of them is the natural world that surrounds us. Often, this world seems invisible, as though it's just beyond what we can see as we drive to work or walk to class, spend the day inside, and make our way back again. Yet this world can easily be seen if we take time from our routines and allow ourselves to see it, even if we are surrounded by an urban environment. This may sound a bit flowery, but I think it's vital that we each slow down and begin to pay attention to, and understand, local biodiversity.

The Fall 2014 term at Transylvania University gets underway on Tuesday, September 2! I feel a sense of great anticipation and eagerness for the semester to begin. In addition to coordinating labs in the Biology department, I'll be leading a non-majors course called BIO 1064: Biology and Human Concerns. Since I have some latitude in designing the course, we'll spend the semester discussing natural history, biodiversity, and conservation issues in Kentucky. We'll use Kentucky's Natural Heritage, edited by Abernathy, White, Laudermilk, and Evans.

You can find it on Amazon.com

This book is beautiful, and could easily pass as a coffee table book. However, many knowledgeable local ecologists, biologists, and naturalists contributed to this book, and as a result it provides the best holistic view of Kentucky's natural history, physical geography, and biodiversity out there.

My hope is that this course will provide my students some basic naturalist skills, an understanding of how natural history has been important to the development of the biological sciences, and why conservation and wise use of natural resources continues to be of critical importance. I also plan to spend as much time as possible outside, learning to identify native trees, birds, and insects! 

Finally, the students will be blogging this semester, and I look forward to reading their posts and seeing what topics they're interested in. I plan to post the links to their blogs as soon as they're set up, so you should be able to check them out as well! 

This should be a great semester!