the Ecology of Ignorance

One of the main purposes of this blog is to provide a reference point, and indeed a compendium, for the various resources I expect to accumulate for those interested in educating himself or herself in the various principle of backyard ecology.  References are important because I suspect that ignorance is a major source of the problem when it comes to the preponderance of invasives in our residential environments.  When I say ignorance I don't mean in it a derogatory way, rather I mean just the simple condition that what people do not know is causing harm.  I sincerely believe that a significant percentage of the population would approach plant selection, lawn care, or landscaping in general in a different way if they understood more about issues at hand.  For this reason I believe one of the core purposes of the Domicle Ecophile is to educate, to eliminate that ignorance.  Let me provide two simple examples to illustrate my point.

Typical signs at a local nursery in the Northeastern US.

First, take a look at a common dynamic in the Northeast; the selection of the 'deer-resistant' plant.  And for a specific example, we'll look at my favorite villain, the Japanese Barberry.  Here is a case where what looks like a simple and innocuous decision is actually the root of a very serious problem. Deer browsing is a serious landscaping problem in the Northeastern United States.  (This is itself an issue due to humans' complete removal of all native predators of deer, but that's another issue for another time.)  The simple choice many landscapers and homeowners make is to choose a deer-resistant shrub like the Japanese Barberry over a plant that is likely to become a deer snack.  Let us consider this: Why is barberry deer resistant? This answer is that deer don't eat it.  For every barberry planted it means one more plant deer will not eat and one more place a deer-susceptible plant cannot grow.  Most of the shrubs that deer eat are the ones with which they have been cohabiting for thousands of years; the ones which are native to North America.  There are notable exceptions, but what this boils down to is as much a choice between exotic or native as it is between deer-resistant or deer-susceptible.

But the story isn't over yet.  Japanese Barberry produces small berries that birds eat.  (The nutritional value of these berries, or lack thereof, can be discussed at another time.)  Nonetheless, the birds spread the seeds and produce new plants.  The plants are tough, not grazed significantly by any North American species, and are fast-growing.  As the plants spread there is increasing pressure on deer to graze the remaining palatable natives and gradually the deer clear out the natives and the barberry happily invade the space left vacant, creating huge monotypic groves.  Monoculture promotes ecosystems lacking diversity at all levels and this is only compounded by the fact that in this case the monoculture plant is nearly useless to native animals.  In some of our state parks I have personally seen sections with nothing but acres of barberry.  Sadly, once these plants escape to the wild what was  supposed to be an innocent landscaping decision transforms into an amorphous, ecological disaster.  I have provided a link to some additional info on the threats posed by barberry from the U.S. National Park Service.  A direct quote from the document pretty much sums it up, "Do not plant Japanese barberry."

Take the case of Buddleia as a second example of the "ecology of ignorance."  The species Buddleia davidii is often sold at plant nurseries and even wildlife stores under the name "Butterfly Bush."  I would suspect that many of my readers have heard of this plant and may even have one.  The plant is advertised as attracting many species of butterflies to its nectar.  While it does attract butterflies to its flowers, it does not provide food to caterpillars.  This is because while adult butterflies do drink its nectar, but like many other exotics the leaves are inedible or unpalatable to their earlier life stages--the caterpillars.  So what's the problem?  The problem is that if there is no food for caterpillars, there will never be butterflies to come to the flowers later.  Remember the life cycle of the butterfly from elementary school?  Far better than an exotic that feeds only adults is a native plant like milkweed that provides food for multiple life stages and can serve as host for reproduction.  What is worse is that in some climates the Buddleia can be an invasive, spreading into wild habitats and displacing native species.  Take a minute to look what authorities in Kings County, Washington have to say of the plant.  The irony, of course, is that many if not most of those who buy one of these plants think that they are helping wildlife.  At best they are installing a second-rate plant with some ecological value, but at worst they are displacing native flora, encouraging nurseries to further stock exotics like the Buddleia, and making it harder for the very butterflies they want to attract to reproduce and exist in the first place.

The bottom line is that the average homeowner probably makes landscaping choices without knowing the full story about what they are planting.  Individual plants might not make or break the existence of individual species, but when those decisions are multiplied by tens of thousands of suburban properties they can make a huge impact.  This is why I will continue to urge homeowners to do some research and find out about what they are planting and how it will affect many animals they may never even see.  Let's create a suburban ecology built on sustainable choices that support our indigenous wildlife rather than exclude it.