On Thursday, October 2nd, I was treated to a lecture by Doug Tallamy at the Finger Lakes Community College. It was quite a drive and I probably wouldn’t have made the trip but my teacher, mentor, and horticulturalist at the Cornell Cooperative Extension here in Jefferson County arranged a field trip for us to attend. It was myself, her, and a couple of other Master Gardeners. And I probably wouldn’t have heard about this event if not for subscribing to the wonderful Wild Ones Chapter of CNY in Syracuse’s invaluable newsletter each month, whose president, Janet Allen, also happened to be there. So, I have many people to thank for giving me the gift of this opportunity. We all purchased his books. I already owned “Bringing Nature Home,” but was looking forward to purchasing Doug’s new book “The Living Landscape.” I am now the proud owner of a signed copy.
Oh, but this is not a book review, even though I do recommend this book. This is an eye-opener. Because that is what Doug did for me years ago when I first read “Bringing Nature Home,” he opened my eyes to the importance of native plants in the garden and forever changed the way I garden. And now, today, he does it again by stressing the importance of native gardens as conservation and sustainability. With concepts like specialization, diversity maintains stability, ecosystem function and homegrown national parks I am viewing my garden, and all landscapes, in a whole new light. (And I am only a quarter of the way through my new book!)
It astounded me to learn that over 90% – 90%! – of insects have a specialized relationship with plants. The Monarch Butterfly is only one example. Learning of the existence of the Bolas Spider (of which I have never seen) is fascinating to me. This spider casts a single string of web with a sticky “lure” on the end much like a fishing line. Incredibly, it is a successful “fisherman” and why? Because the Bola Spider mimics the sex pheromone of a single species of moth within that “lure.” The moth may rely on the Black Cherry tree to reproduce. So, if your landscape is absent of the Black Cherry, it is absent of the moth, and therefore will be absent of the Bola Spider. So the special relationship the moth has with the tree also affects the presence of the spider. This specialization really hit me. I wonder if I have enough specialized relationships in my small landscape to sustain such life? Part of the problem we’re having is that we are introducing so many new plants without allowing the time needed for the specialized relationships to take place. Plants do not want to be eaten! It takes awhile – 100, 200, 300 years? – for an insect to figure out how to safely eat through a plant’s defenses. We are not giving them enough time. “In short, by becoming host plant specialists, insect herbivores can circumvent plant defenses well enough to make a living.”
Perhaps the best example that illustrates diversity maintains stability, Doug shared with us during his talk was his own backyard study of the Chickadee. I am listening to the call of a Chickadee in my garden right now with wonder. We all see Chickadees at our feeders eating Sunflower seeds or stashing them. Because this is what we predominantly see, we don’t realize that Chickadees also need insects. 96% – 96%! – of terrestrial birds in North America rear their young on insects according to my book. I got this when I read “Bringing Nature Home,” but what I didn’t get is that Carolina Chickadees rear their young exclusively on caterpillars – not crickets, not katydids, not millipedes, not beetles or spiders – caterpillars. (These statements are all derived from my new book.) A Carolina Chickadee brings somewhere between 390 and 570 caterpillars to their nest each day, and the parents feed their nestlings for 16 to 18 days before they fledge. That’s 6,240 to 10,260 caterpillars for one clutch of Chickadees folks. Because Doug is an entomologist, he could also identify what kinds of caterpillars the Chickadees were using for food and he knew the host plants of those caterpillars. He points out the Chickadee is a pretty small bird – what would a larger bird require? “What type of landscape is capable of producing insects in the numbers required to support viable food webs? A landscape built from a diversity of plants that have each developed specialized relationships with a diversity of insect species. A landscape occupied by organisms that have interacted with each other over evolutionary rather than ecological time spans.”
“Local extinction is rampant in human-dominated landscapes.” A study by one of Doug’s students found that hedgerows with few invasive plants produced five times more species of caterpillars and twenty-two times more caterpillars than hedgerows in which invasive Asian plants had replaced much of the native vegetation i.e. autumn olive, porcelain berry, Japanese honeysuckle.
Doug flipped through slides of caterpillars and their host plants. The point he made is that some plants only support a few caterpillars, while others, like Oaks, support many more. It was a well received point and very impressive. I planted a Pin Oak in my garden because the Oaks resonated with me from “Bringing Nature Home” as big supporters of life. I planted a Pin Oak because it was available at the nursery. A better choice might have been a White Oak or Swamp Oak because they are indigenous to our area, but I did all I knew at the time and I was concerned with space.
I planted the Woodland Edge section of my garden with layers in mind, but in this new book with Rick Darke, the authors peel back the layers – literal, cultural (influenced by human culture), and temporal – like an onion exploring the importance of each, as well as the importance of how they interact with one another. “As the layered organization of a landscape becomes apparent, it provides a framework for more detailed observation and understanding … to comprehend interactions between elements in the layers makes it ever more possible to recognize stability or to anticipate change … Gardens have layers, too, and an appreciation of patterns and processes in unmanaged systems is a powerful tool for deciding how and when to emulate or intervene in the landscape each of us calls home.”
Observations illustrate these relationships. Because white tailed deer populations are out of balance, woodland shrub and herbaceous layers are affected. Ferns are predominant as they are the least palatable to the deer. Exploring this further through the eyes of Doug and Rick, we question is it soley the shrub and herbaceous layers that are affected? Seedlings are eaten before they can mature – the future understory and canopy – and so the system is, will be, altered. Here is a photo from the book “The Living Landscape” illustrating a study by the Pennsylvania Department of Conservation and Natural Resources who maintain this deer enclosure to demonstrate the effects of deer grazing on woodland regeneration. Notice that the right side, unprotected, is mostly all ferns. The deer are native and so are the ferns, but the deer are out of balance with the plant life so systems and functions are altered. I can plant a bank of native ferns in my garden – great! native plants – but this does not establish a relationship with a woodland shrub layer or canopy layer unless I plant those layers as well, which is the kind of complexity we need to think about when designing our gardens and landscapes if we wish them to function = ecosystem function.
Included in Doug’s talk was a story of “accidental conservation.” This concept is also very eye opening to moi. After you hear about this story, just imagine all we can do! The Atala Butterfly specialized (that word again!) on a slow growing cycad called coontie (Zamia pumila) in Florida. When Florida was first occupied by the Spanish and then Americans, the Seminoles showed them how to eat the roots of the coontie. And so the sole host plant for the Atala (Eumaceus a tala), the coontie, nearly disappeared along with the Atala. Efforts to put the Atala on the endangered species list failed because there was no evidence that the butterfly still existed. Around the mid 1970s, landscape designers recognized the ornamental value of the coontie – a low growing, long lived, evergreen shrub adapted to the dry conditions of South Florida’s sandy soils. Soon, coontie were restored to Florida’s formal landscape plantings. Soon after that, the Atala butterfly reappeared! Imagine what we can do on purpose!
A small excerpt from “The Living Landscape”: Similarly, butterfly gardens that feature milkweed plants are enabling returning monarchs to breed successfully within greater landscapes from which milkweeds have been largely eliminated by development, agriculture and drought. One small 15 by 15 foot garden in a courtyard in the center of Dover, Delaware, produced 150 monarch adults in a single season by including several Asclepias syriaca plants as one of its species. Such successes are truly exciting and demonstrate the importance and potential of private gardens in providing the resources needed by wildlife.
Indeed! And I’ve only just begun the chapter entitled The Art of Observation. I want to leave you with this one thought which I still carry around with me after listening to Doug Tallamy. Our National Parks are not big enough to sustain life anymore – stability. They are too segmented and smaller populations cannot withstand fluctuations in nature such as weather, etc. Doug instilled us with the idea of a “homegrown national park.” The idea is to heavily plant all our gardens – connecting us all – leaving grass or lawn areas only as means to arrive at a destination, i.e. a grassy path to your shed or vegetable garden, or a patch to hold your BBQ. If we all planted this way we could create a National Park – a living landscape – bigger than Yellowstone and the Adirondacks and a host of others combined! Me, I am going to strive to serve up 500 caterpillars a day!