Identifying and Eradicating Invasive Species
Invasive Species – What is all the Bother
For those of you who may or may not have noticed, there is a biological invasion happening right in your backyards. Back in the days, we used to simply worry about Multiflora Rose; that prickly shrub that smells, oh so, sweet in May. Japanese Honeysuckle, not often noticed until its flowers perfume the spring air; when children (and a few adventurous adults) would taste the sweet nectar that covers its anthers. Oriental Bittersweet adorned our fall decorations with berries of gold and red. By comparison the invasive species of today make as lament for those of yesterday.
Porcelain Berry and Mile-a-Minute Vine use Multiflora Rose as a trellis and form impenetrable tangles in our landscapes. Porcelain Berry is still being offered by nurseries for the home gardener who enjoys its sapphire blue berries in late summer. Do these folks understand that this plant is covering our natural areas and smothering the native vegetation? If they do understand, do they care? Mile-a-Minute Vine was first found growing in a nursery pot in Pennsylvania just over a decade ago. It now covers much of the northeast.
So what’s the bother? Why do we care, what’s more why should we care? Most folks enjoy songbirds and butterflies. If they were to understand that the existence of these species is directly related to the health of our native flora; would they then be moved to act as stewards of their own yards in removing invasive species and re-planting native species? Perhaps they would, perhaps not. In the event that you are interested here are some of the facts.
Prior to European settlement, this region was almost entirely forested. Some estimates indicate that the forest cover was more than ninety-5 percent. After settlement, many of the forests were cut to provide timber for the European markets and to grow crops for the settler’s consumption. Today, the forest cover in London Grove Township is a meager 18 percent. Wildlife in this region co-evolved within a forested ecosystem that means insects, birds, amphibians, reptiles and mammals depend on the forest for food and shelter. Complex and synergistic relationships between plants and wildlife developed over the millennia in a stable and balanced ecosystem. When the forest was removed, many of the critical life support needs such as food and shelter were lost leaving wildlife literally hungry and homeless. Since plants provide food for all wildlife either directly or indirectly, anything that compromises plant life manifests throughout the food chain.
Food offered by many invasive plants is not available to many of the insects that form the base of the food chain. Many insects are host specific, meaning that they have adapted certain enzymes that allow them to break down the chemical defenses of the plant and receive nourishment from their host. As these host plants are replaced by non-native species, these insects are not able to find food sources. It is like is going into a supermarket where there used to be an array of food choices and now there are only a couple of different types of food on the shelves. As the diversity of insects decreases so do the number and diversity of birds and butterflies etc. A recent statistic indicates that 1 third of our bird populations are in trouble.
Native Americans managed the forest through burning understory areas to create clearings to make game more visible when hunting. They created canopy gaps so they could cultivate edible and medicinal plants. All of these “disturbances” were relatively minor and did not exceed the recoverability of the forested ecosystem. Today’s disturbances, I liken to a catastrophic illness. When our immune systems are healthy, our bodies are able to defend against infection. When our systems are “down”, this resilience is compromised. It is the same with an ecosystem. Small disturbances are able to be assimilated and can even promote species diversity. However, large scale disturbances like repeated clear cuts, massive soil disturbances created by bulldozers and the like exceed the ability of the system to recover. This imbalance then leaves the system vulnerable to invasion from pests and invasive species. As a result, what was once a diverse and thriving ecosystem is increasingly simplified and its ability to support wildlife and provide function diminishes.
This conditions is what best describes the landscape we live in – a compromised, imbalanced system that has been overrun by invasive species. The populations of some native species, such as White Tailed Deer, have exploded and are creating further havoc in an all ready stressed system. Without natural predators (except sadly the automobile) and with an abundant source of food created by a preponderance of “edge habitat”, White Tailed Deer populations are literally preventing the regeneration of our remaining woodlands through voraciously grazing virtually all of the tree seedlings. This population explosion, along with those of invasive species is symptomatic of a system that is seriously out of balance.
This sad state of affairs is where we find ourselves. If you are one of those interested individuals, what can be done? Since there is strength in numbers if we all do our part, (always the optimist) at the very least, we may feel better, at best, we may be able to preserve some of the integrity of our local flora and fauna. One thing to remember is that nature abhors a vacuum so that anytime an area is not robustly vegetated; it provides an opportunity for invasion. Be mindful of these areas and undesirable opportunities on your own property. Likewise, take care to not trade 1 problem for a bigger 1 such as removing Multiflora Rose and not immediately replanting. This vacuum will quickly be filled with something potentially worse like Mile-a-Minute Vine. From the category of lessons learned the hard way, do not get ahead of yourself. Better to remove invasive species on a modest portion of your property and replant the area immediately, then to clear a large area and not have the funds or energy to stabilize before moving on. Likewise, do not clear and re-plant an area larger than you can manage. As the job of invasive species removal, unlike many other jobs these days, has job security. Just because you spent a summer on your hands and knees cutting and pulling invasive species does not mean that the same area will not be invaded in the future. You need to be honest about what you can manage.
Should you have Multiflora Rose, Oriental Bittersweet, or Porcelain Berry growing in your backyard, your best bet of course is to weed them out before they become large. At this size, the job is relatively simple and can be done by pulling them out anytime that is convenient for you during the growing season when identification is easier. Should you not be so fortunate and you find these species well entrenched on your property, a combination of manual work and the very judicious use of herbicide will be in order. Something to keep in mind is that herbicide works best on “woody” species in late August through September when the energy in the plant is returning to the roots for the dormant period. As distasteful as it is to recommend the use of any chemical, a strong recommendation is for you to perform your own research to determine what you can live with. Just like taking medicine, it is up to us to determine what we are comfortable ingesting. It is the same for any chemical that we apply to the land. We need to understand that there are ramifications for any action that we take. Our astute observation will reveal whether our choices have desirable outcomes. For me, the only herbicides I use (with reluctance) are those glyphosate- based products that are registered for use in wetland areas.
Large Oriental Bittersweet and Porcelain Berry vines may be cut near the ground; herbicide may be applied judiciously to the cut using a paint brush. It is important to apply the chemical within 5 to 15 minutes of cutting before the plant has sealed the cut. The herbicide is to be used according to the manufacturer’s instructions. The remaining vines are to be left in the trees as ultimately they will fall of their own accord. The same technique may be used for Multiflora Rose.
Mile-a-Minute Vine is an herbaceous annual. It is prudent to begin its removal as it germinates. Germination of this plant in this region begins in late April and continues through June. Because the plant has a re-curved barb, it is best to wear gloves when weeding. A rake is effective at times in pulling it from larger areas that are primarily vegetated with this species. Alternatively, spot applications of herbicide during the growing season will also be effective. Take care to not kill off entire areas without being prepared to re-plant. It is important to control this plant before it starts going to seed in July.
If you are not by now thoroughly discouraged, I do hope that altruism will carry you through what can be at times a thankless job. I leave you with a quote from Chris Maser.
“The very process of restoring the land to health is the process through which we become attuned to Nature and, through Nature, with ourselves. Restoration, therefore, is both the means and the end, for as we learn how to restore the land, we heal the land, and as we heal the land, we heal ourselves.”
Written by: Jessie Laurel Benjamin
Photos by: Laura Miller