Today’s Christmas Eve sunrise was spectacular. Fleeting, as always, but well worth braving the chilly air as nuthatches chittered, woodpeckers squawked, and mallards in the adjacent wetland greeted the light with argumentative-sounding quacks.
Winter is the only season that permits sunrises to penetrate the tall trees that I am blessed to share my home with, so I cherish every one I can. I don’t even want to guess how many photos of winter sunrises crowd my files, and I don’t care.
Every sunrise is slightly different, but all evoke the same emotions in me:
- joy at the beauty of creation,
- love for the creatures greeting the morning all around me as I stand on my deck snapping photos,
- and a tinge of melancholy prompted by the fleeting nature of these sunrise moments.
For all my readers who celebrate Christmas, I wish you a very merry one. May you be surrounded by joy and love. May your days be merry and bright. And may all your sunrises be glorious.
As I pondered our seasonal turn to winter, this fell out of my fingers. Happy Solstice to all.
Light a candle against the darkness.
Light a fire, watch it burn.
Beneath the warmth of extra blankets,
dream deeply as the seasons turn.
Feel the light always within you,
your connection to the divine.
Like roots beneath a forest,
we are all intertwined.
Plant dream seeds in the moonlight.
Your heart knows they will grow.
A spring garden of beauty and love awaits you
when it is time to reap what we sow.
I learned a new ecological term this week. Johnny Randall, the Director of Conservation Programs at the NC Botanical Garden, mentioned it while we were discussing material for an article we are collaborating on for the spring issue of their magazine, Conservation Gardener. Although the term was new to me, the meaning behind it was not unfamiliar.
Three researchers from the University of Tartu in Estonia developed the concept of dark diversity in a paper they published in 2011. Their term was chosen to parallel the notion of dark matter in astrophysics. As with dark matter, dark diversity can be inferred from data, but it cannot be seen or directly measured.
Conservation ecologists, especially those attempting to restore or sustain ecosystems, are using the idea of dark diversity to help them assess the health of the system they are studying. Imagine a healthy ecosystem, one with all its components, where every plant, fungus, insect, bird, etc. that should live there actually does live there. This is almost never true anymore. Humans have fragmented and/or destroyed so much now that nearly every bit of forest, field, stream, coral reef, etc. is missing species that were, until fairly recently, components of those ecosystems.
Thus, these days when conservation ecologists attempt to preserve/restore special examples of ecosystems, often those containing rare plants, they not only must identify the species present on the site; they must also attempt to figure out what species are missing. Species still present can be seen and counted, their viability assessed; this is visible diversity. The absent species, the ones that should be there but aren’t define dark diversity.
I’m oversimplifying the concept a bit, but, basically, ecologists estimate dark diversity by looking at species diversity in the region in which their study site is located. If, for example, a section of forest being restored was missing wood thrushes (one of my favorite summer visitors of our forests), but those birds were known to live in patches of forest in the region, wood thrushes would be identified as part of the dark diversity of the study site – a species that should be there, based on its presence in the region, but is absent.
As I can best understand the concept, by measuring the amount of dark diversity, ecologists can better guess how difficult it would be to restore a given site to full diversity – to bring back all the missing species that should be living on a site but aren’t.
Dark Diversity on Our Five Acres
When Johnny Randall mentioned the concept of dark diversity, it immediately resonated with me, because Wonder Spouse and I have been playing with the dark, as it were, on our five acres for over three decades now. When I first saw this land on a cold January day almost 33 years ago, it was an ecosystem with substantial dark diversity. The previous owner had eliminated almost all the native grasses, wildflowers, shrubs, and understory trees, leaving only towering canopy-level trees and a lawn full of non-native grasses. I could hear birds, but I rarely saw them in our yard. There was nothing for them to eat near ground level, and no good nesting sites.
However, the floodplain forest on the other side of the creek teemed with ferns, wildflowers, and a healthy shrub layer. Bird song echoed across our empty yard from that area. I knew that all of those species should also be living on our side of the creek. Those species not present on our land but living nearby were dark diversity – the missing pieces. I wanted to bring them back.
Through trial and error, luck, and hard work, we have rebuilt much of the species diversity that lived on our property before it was damaged by the previous owner. Fruit-bearing shrubs provide food for an array of species. Dense plantings of shrubs, grasses, ferns, and wildflowers provide food and shelter for insects, reptiles, amphibians, birds, and an array of mammals.
I am certain that our amateur habitat restoration efforts would not pass muster with the professionals, but I think our results speak for themselves. What once was unseen – dark – is now visible. The species that were nearby but absent on our land have returned. I do not have adequate words to describe how deeply gratifying it has been to bring the dark into light, to bring the missing species home.
Contemplating the dark seems an entirely appropriate occupation as we rapidly approach the darkest night – winter solstice. A wise person recently told me that, when navigating dark times, it is important to trust the invisible. It seems wise folks from astrophysicists to ecologists follow this guidance. Darkness – what we cannot see with our eyes – teems with life, with knowledge. It may well be true that we can learn more from the unseen than from our visible world.
Where is your heart? I ask, because I’ve been thinking about a familiar cliché – home is where the heart is. I’ve been asking myself that question as I ponder what I am thankful for during this season of blessing-counting. Where is home for me? Where is my heart?
My instant answer is that my home is, above all else, my soul mate, my Wonder Spouse. With him, I am always warm and safe and entirely loved. He is a blessing I try never to take for granted.
Home is also this five acres of land Wonder Spouse and I have nurtured together for over three decades. To the real estate industry and government, we are owners of this piece of Piedmont paradise, but we know better. We are collaborators with all that lived here before us and those who have arrived since. We know the trees do not belong to us, though we do our best to care for them, and always appreciate them. We know the birds, frogs, foxes, and turtles who dwell among us do not belong to us, but we welcome their presence and try to encourage it by creating habitats that are heart homes for them.
Wonder Spouse and I have worked hard to make our five acres healthier and more diverse than when we first arrived. Stripped gradually of human artifices such as lawns and non-native plants that feed no one, this Piedmont patch grows more alive with every passing season. Truly, this land is our heart, our home, our family, and we feel deeply blessed to have found it, joyfully embracing our work to return it to vibrant native diversity.
I know how blessed we are. Many humans around the globe have no home. They are hungry, often cold and afraid. To my mind, the inequities among humans reflect attitudes about all our relationships, beginning with how we treat Mother Earth and all her non-human inhabitants. Perhaps the perpetrators of these inequities rationalize their behavior by believing they are doing it to Someone Else.
However, I believe that anyone with open eyes can see the interrelatedness of everything, from the air we breathe and the water we drink to the food we eat. Equally accessible sustainable ecosystems are necessary for all our families to thrive.
On this American day of thanksgiving when you give thanks for your family gathered round tables laden with abundance, for their health, for whatever other blessings you acknowledge, please consider also giving thanks for the fact that none of those blessings is possible without the blue-green planet that nurtures everything, home to us all. Give thanks for Mother Earth, and consider making a promise with your family to do more for her sustainable health. It is the only way we may be assured of Thanksgivings for many generations to come.
As promised in my previous post, this is my summary of the presentations given on the second day of the virtual conference of the NC Invasive Plant Council this past week. I apologize for the length. I tried to be as succinct as possible.
That was the title of the talk, just the generic name of the herbicide better known to many by the commercial product with the name that rhymes with groundup. This presentation was given by a professor from NC State University. Although it is much more than a land-grant institution concerned with agriculture and engineering today, those areas were its original focus, and are still very important. Much academic effort remains focused on supporting what I think of as the traditional agriculture and horticulture industries. I assume it is that focus that explains the approach taken by this speaker. I feel obliged to go into some detail about this presentation. I think my reasons will become evident quickly.
From my perspective as a well-educated woman with a substantial knowledge of ecology and gardening, his talk began inauspiciously. His opening slide portrayed a woman dressed in the 1950’s cliché style of a “typical housewife” – perfect dress, high heels, permed hair, and make-up. She was standing on an immaculate green lawn in front of a house. Behind her, she pulled a large clunky-looking machine that was spraying what I assume was supposed to be an herbicide mixture onto her lawn, all while smiling prettily for the camera.
I pondered what message the speaker intended to convey with this image. Was he harkening back to “the good old days” when women knew their place and happily spread poisons without worrying about safety protocols? Did he think he was being funny? I tried to continue listening with an open mind, but the talk went downhill from there for me.
This professor was not the most coherent of speakers, but I think his primary point was that anyone worried about glyphosate is misinformed and should shut up and leave the poisons to the “experts.” He showed a few graphs demonstrating how much less toxic glyphosate is than some of the herbicides farmers used in the recent past. That’s true. Glyphosate doesn’t persist in the environment as long as those more toxic herbicides, and it is probably less dangerous to humans.
His next words raised my hackles. He showed the label from the Non-GMO Project that appears on food products that have been certified by that organization. At the same time, he said, “Not to be sexist or anything, but women buy most of the food in the house.” I braced myself. As best as I could make out, his point was that women are so stupid that we think the Non-GMO Project label means the food was produced without the use of herbicides and that makes the food safer, which is why we buy it. I can’t speak for women everywhere, but I can tell you that I – a woman for some decades now – know the Non-GMO Project label certifies that the food was not created by bioengineering methods that genetically modified it.
The speaker never really articulated his objection to the Non-GMO label, but I can guess what it might be. Traditional agricultural operations that produce hundreds of acres of soybeans, corn, and other staple crops have been moving substantially toward the use of genetically modified seeds that contain genes making the food crops resistant to the application of glyphosate. Now, instead of needing to till crop rows to control weeds, farmers merely spray their entire fields with glyphosate, thus killing all the weeds while the food crop survives.
I imagine that my readers can come up with all kinds of reasons for being uncomfortable with the idea that food they might eat is grown this way. Personally, I’ve been grateful for the Non-GMO product certification label since it began appearing. And I’ve always known that the label does not necessarily imply that the food was grown organically and/or without the use of herbicides/pesticides. It merely indicates the food was not bioengineered so that poisons could kill weeds in the field without killing the crop.
After insulting female food-buyers everywhere for being stupid enough to conflate non-GMO foods with those grown organically, the speaker spoke at length about the fact that no government agency has declared that glyphosate causes cancer in humans or other mammals. He made a point of stating it that way for good reason. Scientists have been studying the effects of glyphosate on non-mammals for quite some time. Here are a few relevant journal articles:
- Glyphosate inhibits melanization and increases susceptibility to infection in insects
- Common weed killer – believed harmless to animals – may be harming bees worldwide: Glyphosate appears to alter the bacteria in the insect’s guts, making them more vulnerable to infection
- Effects of the Herbicide Glyphosate on Honey Bee Sensory and Cognitive Abilities: Individual Impairments with Implications for the Hive
- Amphibians Are Not Ready for Roundup
- Chronic exposure to a glyphosate-based herbicide makes toad larvae more toxic
For those who think I’m cherry-picking journal articles, here’s one for the pro-glyphosate team:
I am not an expert on herbicides, but it appears to me that the most generous statement one can make is that, at best, data are mixed on the impacts of glyphosate on non-mammalian wildlife. I suspect that, as the last article above states, when used correctly at appropriate concentrations and appropriate application techniques, glyphosate is a useful tool in the battle to control non-native invasive plants. If the presenter of this talk had said this, instead of “mansplaining” to women he deems too stupid to understand, I would not be writing all this. However, because this professor’s job is to support the agriculture industry’s use of glyphosate, I think he chose to obfuscate with a tirade about non-GMO labeling on food products. Moving on…
Response of Invasive Plants to Fire at Picture Creek Diabase Barrens
After the previous talk, it was a great relief to me when this presenter began. A plant ecologist, she is the Program Manager for the North Carolina Department of Agriculture’s Plant Conservation Program, a group whose mission is to protect rare plants in North Carolina.
Picture Creek Diabase Barrens is a site containing a remnant community of Piedmont prairie plants. Hanging on by the merest of threads, it survived because it grows beneath high-tension powerlines, which means the power company has been keeping that area free of forest encroachment for decades. Until fairly recent times, the trees were removed manually, which is probably why the rare plants survived. These days, of course, utility companies prefer to spray herbicides on such lines. In my area, they do it using helicopters. Many areas deploy teams of workers with backpacks full of herbicide to kill everything growing within the utility right-of-way.
Conservation groups, including the NC Botanical Garden and the Friends of Plant Conservation have been helping to restore this particular rare ecosystem. In addition to tackling the non-native invasive plants encroaching on the area, they’ve collected seed from some of the rare plants, which they grew out and then planted on the site. Controlled burns are very effective at controlling unwelcome plant species in Piedmont prairies. It was the way they were maintained by Native Americans before European colonists arrived. Burns don’t always control all unwanted species. Careful applications of correct concentrations of glyphosate are also used to battle invasive species on this site. The presenter emphasized the need for careful applications. Her staff is trained to recognize desirable and undesirable species. It is slow, painstaking work to move through this fragile plant community spraying herbicide only on unwelcome species.
The speaker emphasized this because of unhappy experiences with crews from the power company that are paid to spray herbicides on the powerline right-of-way. They are not trained to recognize one plant from another. They douse anything green with poison, and they move quickly, which may explain how they missed the signs marking this protected rare plant community as a no-spray zone. The speaker told us it has taken years of hard work to persuade the power company to allow conservation experts to manage rare plants beneath powerlines. After a recent incident in which power company contractors missed the signs and sprayed herbicide on the protected rare plants in this location, the speaker told us all parties sat down together again to discuss how they might prevent this from happening in the future. The good news is that they all agreed to meet together once per year for the indefinite future to ensure that all parties are always current on agreed-upon procedures, thereby decreasing the likelihood of future communication lapses.
Invasive Plants in Glades
The man who presented this talk is a Public Lands Field Biologist for MountainTrue, a conservation organization that “champions resilient forests, clean waters, and healthy communities in the Southern Blue Ridge.” I would describe his interesting slide presentation as, at best, tangentially related to the subject of non-native invasive plants. He spent almost all of his time describing the interesting, often rare plants that occur in glade plant communities. His definition of what constituted a glade was a tad fuzzy to me, but suffice it to say these communities grow on the sides of mountains on relatively steep slopes. He mostly showed us many photos of interesting plants. At the end of his talk, he mentioned the non-native invasive plants that he usually sees encroaching on glade communities. I don’t remember if he talked about how he controlled them.
Emerald Ash Borer and Other Invasive Pests
As far as I’m concerned, this was the most depressing presentation of the conference. The speaker, a Ph.D. entomologist for a local big tree-care company, described the non-native invasive insect species that he believes will impact our local ecosystems most significantly. I’ve written several times about one of them. I may have mentioned the second invader at least once, and I don’t think I’ve described the other one before.
I’ve written about this phenomenally destructive insect several times in this blog. Enter “Emerald Ash Borer” in the search box to find those entries. I also wrote an article about it for the magazine of the NC Botanical Garden.
This insect from Asia is systematically killing every ash tree in North America. In northern states like Michigan, the only ash trees still alive are the ones treated every other year with systemic insecticide. The insecticide is injected into the tree, the poison permeates the entire tree, and any insect that takes a bite of a treated tree dies. Federal agencies are experimentally releasing four different species of parasitic wasps from Asia that target varying life cycle stages of EAB. The speaker said that at least one of those wasp species was found the following year, meaning it successfully reproduced by feeding EABs to its larvae. This potentially good news is not great news. First, these releases are still experimental. Regular folks and even tree companies, such as this speaker’s employer, do not have access to these wasps. Also, the speaker noted, no one believes these wasps can eradicate EAB. At best, if the wasps successfully multiply, it might be possible – maybe – for the wasp and EAB populations to reach a sort of truce that might allow some ash trees to survive. Maybe.
A lot of us were hoping, I think, that the wave of marauding EABs would pass through an area, then leave after killing all the ash trees. Alas, according to this speaker, that is not what is happening. Up north, where EAB has been present for 20 years, he saw instances in which a homeowner decided it was safe to stop treating the ash tree on their property, because all untreated ash trees were dead. In such cases, EAB infestations killed such trees five years after insecticide treatments were stopped.
The speaker told us that it is hard to tell when EABs have infested an ash tree, because they begin by boring into branches at the top of the tree, where it is hard to see the dieback. By the time most folks notice their ash trees are unwell, EAB infestation is too far along for systemic insecticide treatments to be effective. He said that if more than 30% of the branches in the canopy are dead, the tree is doomed. He also said that he has seen ash saplings with trunks the diameter of his thumb infested with EAB, which is how the invader persists in an area indefinitely. The species also enjoys dining on our native fringe trees. Barring a miracle, I think it is safe to assume North American ash forests are doomed.
He also mentioned one other fact about dead ash trees that I did not know. When dead, this species becomes dangerously brittle very quickly. He told us that any “tree expert” who claims he can climb your dead ash tree to cut it down from the top is risking his life. No sane arborist, he said, will ever climb a dead ash tree, because it can break and send him tumbling in an instant. Either the tree must be felled in its entirety by cutting it at its base, or a bucket truck must be used to safely access the top of the tree to remove branches.
When the non-native Redbay Ambrosia Beetle lays its eggs inside plants in the laurel family (Lauraceae), it also injects a fungus, called Laurel Wilt, that kills the tree within months. Redbay (Persea borbonia) is a dominant member of plant communities growing in the southeastern coastal plain. In North Carolina, when you drive past areas where this species once dominated, you see miles and miles of dead trees.
Redbay Ambrosia beetles also kill spicebushes (Lindera spp.) and sassafras trees in the Southeastern US. Somehow the beetle has made it to California, where it is posing a grave threat to avocado groves and native California bay laurel trees. The speaker told us that female Redbay Ambrosia beetles are parthenogenic, which means they lay fertile eggs without the need for insemination by a male. One female beetle, the speaker told us, can kill a tree simply by laying her eggs in it.
The speaker joked about the beetle as a grave threat to guacamole lovers everywhere. I’m more worried about Spicebush and Palamedes Swallowtail butterflies. Their caterpillars dine exclusively on plants in the Lauraceae family. And think of the native fruit-eating birds that rely on the fruits of redbay, spicebush, and sassafras. What will they eat when all these species are dead? He also mentioned that the latest data show this insect has been detected in a county less than a hundred miles from mine. It is moving inland from the coast, no doubt on the lookout for spicebushes and sassafras trees.
I warned you this speaker’s talk depressed me.
Study the pictures in the link above to learn what this insect looks like. If you see it, report it to your local extension agent. The speaker said this insect is not quite in NC yet, but is expected any time now. This is not good news.
Larvae of this insect happily eat and damage many different species, including fruit trees. According to the expert, this insect may not kill trees outright, merely damage them. Being from Asia, they evolved with Tree of Heaven (Ailanthus altissima). This Asian invasive tree has invaded North Carolina forests and roadsides and is a favorite food of Spotted Lanternfly – just another example of why non-native invasive plants are not our friends.
The speaker showed a short, truly creepy video of thousands of larvae of Spotted Lanternfly swarming up the trunk of a fruit tree, covering every inch of it. It reminded me of videos of fire ants swarming over an animal. Scary stuff.
The entomologist said the larvae damage but do not usually outright kill trees. However, they do kill vines, and the larvae love to eat vines, especially grape vines. The speaker says he’s even seen this insect kill poison ivy vines. I wanted to ask him if he knew whether it would eat Asian wisteria or kudzu – two Asian invasive vines I’d love to see disappear, but the virtual format of the meeting and a tight timeframe did not give me that opportunity.
I am assuming that the insects kill vines, because vines are smaller. The larvae literally drain them dry. He emphasized that the wine industry is terrified of this insect, because of its fondness for grape vines. He said that Spotted Lanternfly has been sighted in western Virginia along its border with NC, just above NC’s Yadkin river basin – a region acclaimed for its wineries.
Breaking News Regarding NC’s Spotted Lanternfly Situation!
A Master Gardener friend, just pointed me to this article. The NC Dept. of Agriculture and Consumer Services Plant Industry Division has recruited two canines to aid in detecting this insect, which the experts suspect may have already begun infiltrating the state. Here’s hoping their excellent noses can find early infestations that their human coworkers can eliminate!
I hope my posts about this conference have been helpful. When the NC-IPC makes videos of the presentations available on their web site, I’ll note that in this blog, so that you can view them yourself and draw your own conclusions.
This past week, I attended the annual conference of the North Carolina Invasive Plant Council (NC-IPC). The continuing pandemic necessitated that the conference was virtual. The up side of that was that I didn’t have to travel or pay anything to attend. The down side was that I was thoroughly depressed by most of what I heard from the experts. This post summarizes the presentations given on the first day of the conference.
NOTE: To offer a little visual relief, I’m interspersing recent photos taken in my yard. They have nothing to do with the subject, except to serve as reminders of the beauty and diversity of native Southeastern Piedmont flora and fauna.
Most of the people who attend this conference about non-native invasive plants are professionals who deal with these plants daily as part of their jobs. Many of them work for conservation organizations that are trying to preserve special ecosystems and/or rare/endangered plants in preserves scattered across North Carolina. Some attendees are university students and professors who study related subjects, such as the impacts of non-native invasive plants on our native ecosystems. Some are associated with botanical gardens and plant nurseries. Some run small companies that specialize in invasive plant removal and habitat restoration. And some are just plain folks like me, who like to keep abreast of what invaders the professionals are most worried about and the methods they are using to combat non-native invasive plants.
Before attending the conference, I assumed that the NC-IPC was still a non-profit organization, so I sent them $20 to re-join the group. However, after the conference, I got a note from an officer in the group who thanked me for my donation and warned me it isn’t tax-deductible, because the group lost its non-profit status. He did not elaborate, but I’m guessing that this all-volunteer organization fell into disarray during the pandemic, and necessary paperwork wasn’t filed. I’m sure they aren’t the only organization still struggling with such issues. The NC-IPC officer did note that the group is working to regain its non-profit status. I wish them well.
Attendees were assured that all virtual presentations were recorded and will be made available to us. I hope so. I missed bits of some of them, and others showed relevant URLs in slides that I didn’t have time to jot down. I’m hoping they’ll simply put them all up on their web site, so that everyone can benefit from the presentations.
While we wait for the recordings to appear, here’s my summary of what I learned on the first day of the conference. I apologize to presenters in advance for any inaccuracies in my summaries. It is hard to take notes, watch slides, and investigate URLs simultaneously.
Exotic Invasive Seed Bank
The professor from UNC-Asheville who gave this talk demonstrated some out-of-the-box thinking that I appreciated. She spoke about Living Web Farms, an organization in three locations in the Asheville area. She described the group as experts on the cutting edge of all aspects of organic, sustainable gardening/living, and she mentioned a product they use, called EM-1, which is a microbial inoculant. As best as I can tell, EM-1 is a concentrated soup of fungi and bacteria that, when diluted and applied to soils, stimulates impressive vigor in plants. The professor said the presentation she heard about it made claims about EM-1 that included elimination of body odor, among other things. She did not provide details.
However, she did apply EM-1 to the soil in her established vegetable garden and got what she considered to be very beneficial results – improved vigor, more fruit production, disease resistance – everything a gardener wants. It also supposedly provides improved seed germination. This clever professor decided to test that last claim by applying EM-1 to test beds of seeds of plants, such as alfalfa. In some plots, she added a bit of sugar or molasses to the mix, because, she said, sugar often improves seed germination. This was news to me.
She discovered that EM-1 most definitely improved germination rates of seeds in her test plots. She wondered what would happen if she added a higher-than-recommended concentration to seed beds. The alfalfa germinated at impressive rates, but the radicle – the root tip – died, which meant the entire plant died. This led the professor to wonder if applying this higher concentration of EM-1 to beds full of seeds of non-native invasive plants would cause these species to also germinate and die. I won’t bore you with the details, but it appeared likely that she did succeed in encouraging germination of weed seeds at high rates, and those seedlings then died.
Why does this matter to those of us attempting to control invasive plants? Because seeds of plants like Japanese stiltgrass can remain viable in the soil for 7-10 years. However, if one had a way to encourage all those seeds to germinate and die simultaneously, it might be possible to exhaust their seed banks (seeds lurking in soil), thereby reducing populations of these pernicious species.
I think this is a gosh darn clever notion. I especially like it because no poisons of any kind were necessary. I hope she pursues and refines this research so that “regular folks” can try this approach. Meanwhile, I have ordered a bottle of EM-1 to test out on my vegetable garden. I’ll let you know what happens.
Bird Friendly Landscaping
The woman who spoke next is the current president of my local Audubon chapter. This local group has been advocating successfully for restoring native plants to landscapes in order to improve habitat for native wildlife, especially birds. The group’s very professional Web site is jam-packed with wonderful information on this subject. Readers interested in learning more should start here.
Using Imazamox to Control Japanese Knotweed
I confess I sort of snoozed through this man’s talk. If the subject is of interest to you, check the NC-IPC Web site for videos of the conference when they appear.
The Skewed Logic of Invasive Defenders
The man who gave this talk is an active conservationist who has founded local groups to restore/preserve native ecosystems in areas where he has lived. He is a very thoughtful, articulate guy, and feels obliged to argue with folks who write/speak in defense of non-native invasive species. Whole books have been written about this. These invader-supporters advocate a live-and-let-live approach, saying non-native invasive species have a right to be here even if that means entire native ecosystems perish as a consequence.
The speaker’s presentation described the most common arguments invasive-defenders make, and then identified the fallacies in those arguments. He also recounted how he has debated – in writing and in person – with some of these invasive-lovers with mixed results. In Nature’s Best Hope by Douglas Tallamy, one of the appendixes in the book offers counter-arguments to those who advocate on behalf of non-native invasive species. It saddens me that this is necessary.
NC-IPC’s Ficaria verna Program (as a model for others)
The common name for this invasive plant is Fig Buttercup. It is a relatively recent invader to our area, notorious for overwhelming native wetland habitats. It has a pretty flower, which is how it got here. The presenter described how the NC-IPC has allotted money for an education campaign about this plant in the Research Triangle area of North Carolina, where the invader is beginning to get a foothold. For those of you who live in this area, check out the application (Find Fig Buttercup Near You!) they’ve built to help you figure out how close this invader is to your property. This link from the Duke Forest web site describes this invader and why it is a problem. Please keep an eye out for this invader wherever you live. It is tricky to eradicate.
Invasive Plants in Urban Forests: Effects on Forest Structure and Arthropod Communities
The woman who gave this presentation described her Ph.D. thesis, as indicated in the title. I’ve found that newly minted Ph.D. earners are often unable to summarize their work. After all, they’ve been immersed in the minutia of their subject matter for years. They probably dream about it. It is thus understandable that this young woman began by describing in exhaustive detail the methodology she employed in her study. Forgive me, but it was lunch time by then and I was hungry. It was the last presentation for the day, so I left the meeting to eat lunch. I figure I’ll zip through the video to her conclusions when that video becomes available. I’ll be surprised if she did not find a reduction in overall arthropod species, and probably a change in species proportions, because that’s what usually happens when invasive species disrupt native ecosystems. But I’ll check when the video becomes available.
Thus ended the first day of presentations. I found the presentations during the second day to be, in order of presentation, really annoying, interesting and inspiring, interesting, and very depressing. I offer details in the blog post that follows this one. I’ll post it tomorrow.
All gardeners know that fall is for planting. It also marks a rise in wonderful presentations on gardening-related subjects. Case in point: the amazing Debbie Roos, one of the agricultural extension agents for Chatham County, NC, will give what promises to be a great webinar from 6:00-8:00 p.m. on November 10.
To read more about Creating Wildlife Habitat with Native Plants and to register to virtually attend, visit the link. You will learn much, I promise!
For those of you deeply interested in invasive plants, the expert members of the NC Invasive Plants Council will be virtually gathering for two half-days of presentations on November 9-10. Presentations can get a tad technical for the layperson, but you will learn about control methods, which species the experts are most worried about, and other useful information.
You can attend for free, but please consider joining the group to help fund their efforts. To see the agenda and register, go here.
Greetings, my fellow native plant lovers!
This post is to alert you to what sounds likely to be an excellent virtual presentation by experts on North American oak species, including how many of those species are declining and how we gardeners can help reverse that trend.
The Zoom presentation will be on Tuesday, November 9 from 7:00 – 8:30 p.m. EST.
For a small fee, tune in to learn much from the folks who know much.
For details, go here.
If you haven’t read Douglas Tallamy’s book, The Nature of Oaks, I highly recommend that you put it on your to-read list. This book is shorter than his others, because he focuses on one tree species – oaks – instead of entire forest and field ecosystems. By so doing, he is more successful at vividly painting a picture of the complex web of life supported by these long-lived forest giants.
A White Oak’s Tale
To tell the story of oaks, Tallamy centers his tale around one oak tree, likely planted by a blue jay as an acorn several decades earlier. Every chapter chronicles one month in the life of the tree. The entire book is worth reading, but with autumn’s recent arrival, I want to focus today on leaves – the ones discarded by deciduous trees about this time every year, including most oak species. When left alone as Nature designed them to be, these fallen leaves form what Tallamy rightly describes as “priceless litter.”
Magic Beneath the Trees
March is the chapter in which Tallamy tells readers about the magic of fallen oak leaves (He spent his October and November chapters on acorns). As an entomologist, Tallamy is better acquainted than most with the millions of insects and other creatures – most quite tiny – that spend their lives in leaf litter. Soil ecologists call these creatures detritivores. They consume dead plant parts or the bacteria and fungi that help break down plant cellulose in fallen leaves. Dozens of species of moth caterpillars are part of this mix; they eat dead leaves instead of green ones. Of course, these creatures are also eaten by detritivore predators, which number in the hundreds of species. These leaf-litter dwellers provide a critical function by recycling nutrients in dead leaves back into forms plants can absorb via their roots.
All fallen leaves contribute to this mostly unseen web of decomposers critical to nutrient recycling that fuels all life. But oaks, Tallamy tells us, create leaf litter that sustains decomposer populations better than all other tree species. The 700,000 leaves that fall from a mature oak tree decay more slowly than those of most other species, providing ideal litter for up to three years. Decomposers need consistent conditions to survive. Bare soil cannot sustain them; it lacks the nutrients and even moisture levels they need. Slowly decaying oak leaves piled beneath their mother trees provide ideal conditions for the occupants of this intricate food web to perform their magic.
Water for Tomorrow
Tallamy notes that a thick carpet of leaf litter also acts like a sponge during rains. Instead of running off bare ground into storm drains, raindrops soak into leaf litter, which is especially beneficial during heavy rains. Tallamy notes that almost all of a 2-inch downpour – more than 54,000 gallons/acre – is absorbed by leaf litter in an oak forest. Slowly, that water seeps down into the water table, where we and the plants can use it in the future.
While that captured downpour is seeping through the litter, it is purified. Excessive nutrients (for example, runoff from overfertilized lawns) and pollutants are captured by the litter, allowing clean water to filter down to the water table. Instead of flooded streams full of pollutants and eroded soil, clean water slowly seeps downward, replenishing streams downhill gradually, ensuring that flora and fauna relying on those aquatic environments are not disrupted.
More Oaks for More Magic
Tallamy’s message in this book is straightforward. He asks that we all plant oaks appropriate to our region now. It is true that oaks planted now will not mature in our lifetimes, but that is not a reason not to plant them. Gardeners know. We plant for our grandchildren. We plant to enrich habitats for native wildlife. We plant to heal our deeply wounded planet. We plant for the magic created by our vision and effort – not just oaks, of course, but yes, definitely oaks too.
This fall – the ideal season for planting trees and shrubs in the Southeastern Piedmont – please do plant some oaks and other native trees and shrubs. But there is something else you can do that will help. Stop destroying the leaves your plants return to Mother Earth this season. Leave those leaves in place wherever possible. If you must move them, move them gently, to minimize damage to the tiny creatures using those leaves.
Leave Your Leaves
In my yard, wherever practical, I simply rake fallen leaves around their donor trees. In the few areas where I’m still maintaining a “lawn,” I gently rake the leaves around nearby trees. I’ve created a wonderful, increasingly spongy leaf litter bed in my front yard over the last two years by raking about half of the fallen leaves from a massive southern red oak around two ornamental trees. Their leaves also contribute to the litter, but it is definitely those slowly decomposing oak leaves that have created a magically moist, fertile bed into which I’m now adding native ferns and spring ephemeral wildflowers.
Store-bought mulches cannot substitute for leaf litter mulch. They don’t contain the nutrients the millions of detritivores need to survive. It is past time for us to discard old landscaping practices that promote military neatness. Leaves are not the enemy. They are our salvation.
My local Audubon chapter (New Hope Audubon) is currently conducting a wonderful program in collaboration with Triangle Community Foundation and Keep Durham Beautiful, Inc. to promote preserving our leaf litter in place. It’s called Leave Your Leaves. The campaign provides brochures, posters, and yard signs promoting this program. You can read all about it here.
Even if your aren’t a Durham, NC resident, please consider visiting the Pledge To Leave Your Leaves link and signing the pledge. The grant that provided funding for this effort is tracking the number of folks who sign the pledge as a measure of the campaign’s success. If this campaign is successful, it will be easier to win future grants for additional environmental education programs.
Learn More About Healthy Yard Alternatives
Next Thursday, October 21, one of my area’s local conservation organizations (Chatham Conservation Partnership) is holding its quarterly meeting. It will feature several speakers presenting information on healthy yard alternatives. The good news for all my readers is that this meeting will be virtual. If you have the time and a decent internet connection, you are welcome to register and attend the meeting at no cost to you. For details on the meeting and how to register, go here.
A big step toward bringing the magic of a healthy ecosystem to your landscape is leaving fallen leaves in place to shelter the millions of tiny creatures who need them. They, in turn, feed plants with the nutrients they recycle. And the plants feed us all.
Bring back the magic. Leave your leaves.