Tour Stop 3: Biodiversity
From far away they came, European starlings, kudzu vines, purple loosestrife, gypsy moths, long-horned beetles, and wooly adelgids, to our backyards to etch away at the fabric of nature that native species once knew. In many cases these species were brought here with the best intentions: to control erosion (kudzu), to beautify gardens (loosestrife), for experimentation (gypsy moths) and even to celebrate Shakespearian writing (starlings). But all have in some way negatively impacted our country’s biodiversity.
The picture you see here is one of many examples of our efforts to combat foreign invaders. Watershed Association volunteers have replaced the non-native multiflora rose and tartarian honeysuckle that covered this area with an early successionary stage now dominated by a variety of native plantings. Where once two species of plants existed, there are now over a hundred (see database of plants and animals found on this site). With all this diversity we gain the added benefit of attracting other species that feed, lay eggs and utilize native plants to fulfill an aspect of their life history.
This diversity strengthens and stabilizes the system so that it is better equipped to handle disturbance. Think of it in terms of a scaffold. You wouldn’t dare to climb up a scaffold that consists of only three or four supports, but one with a hundred would certainly be secure. The butterflies, wasps, bees, beetles, birds, mammals, amphibians and reptiles that take advantage of our plantings act like “biostrings” that attach themselves in some way to other “biostrings,” all the while adding to the stability, vigor and strength of the system.
Nature’s wall-to-wall carpet. Hard to believe, but there is a pathway here, delineated by log railings. It has been completely hidden by stilt grass, an invasive species.
The photographer photographed. Blaine documents the presence of one of our threatened species, a wood turtle. One indicator of a healthy wetlands eco-system is the number and variety of the plants and animals found there.
Floral Miscreants
“The Earth does not belong to us, we belong to the Earth” — Chief Seattle
Excepting the problems associated with escalating deer populations the greatest threat to our success as land stewards deals with the escaped convicts of the botanical world. I am referring to invasive plants that have found their way to this country by a number of insidious ways which I will explain shortly. Plants that have found their way to places they never existed before usually do well in an environment devoid of competition. Many of these plants can “take over” in short order once freed from competitions shackles. On our Conservation Area Site we wrestle with four plants on the “most wanted list” of floral miscreants.
First and foremost is the barbed wire shrub called multiflora rose. Farmers call this plant “pasture snatcher” in light of the fact it can grow very fast and take over an abandoned field in less than a couple of growing seasons. This plant can be found throughout the site and takes endless man-hours to remove. Careful attention must be taken to remove the entire plant and root stock in order to ensure complete annihilation and success against new shoots from rearing their ugly heads the following year. Any one who has had this unenviable usually goes away with a little less blood volume in their system due to the micro-cuts this plant delivers. If I had a dollar for every curse word I heard during the removal of this beast I would surely be sipping martinis on some island right now.
This shrub is not without its merits. It provides good cover for many animals, especially nesting songbirds that take advantage of the protection the plants thorns provide. In late winter the rose-hips are consumed by small mammals and songbirds that await the arrival of spring, and can often mean the difference between life and death in times of severe winters. It is also well known to those who have chanced by it in spring when in bloom, where the redolent scent of its flowers graces the air. We have left this plant alone along the steam banks and ditches in order to control erosion and take advantage of the shrub’s fore-mentioned attributes.
The reason multiflora rose is here in the first place is due to the Department Of Transportation’s (DOT) planting of the shrub along the side and in the median of highways across the nation. They thought it was a good choice because of all this plant had to offer from an aesthetic, and wildlife protection standpoint, never once imagining it would spread throughout our forests and farmlands as it has.
Multiflora rose will never be fully eradicated on our site and will always need constant vigil and maintenance to control. In many ways this is indicative of everything we must do to steward our property effectively.
Number two on the most-wanted list of floral reprobates on our site is the pervasive and ever-present tartarian honeysuckle. Many of our native honeysuckles are out-fought by this Asian immigrant. Like most honeysuckles the flowers give off a pleasant smell and the red berries can be an attractive element in landscape design. This is the most likely reason why it was widely planted and helps explain why it has escaped into our woodlands. Because it is not favored by deer it is one of the only plants that you see in the shrub layer of our forest community. It seems to prefer floodplains and bottomland environments where its seeds are spread as the undigested part of songbird and small mammal droppings. I believe that white-footed mice play a major role in this plant’s success on site. Our trapping survey of mice in the summer of 1999 gave us a glimpse into the population size on the property. In some areas that we surveyed we would achieve 80% positive traps (The traps we used were non-lethal capture-and-release traps). I must reiterate that this is just a glimpse of the potential for a sizable population of white-footed mice and that a more formal survey with statistically significant parameters is needed to draw a more credible conclusion. This being said, we know that songbirds only consume this berry when other more desirable types are depleted. How then is it that this plant has found its way to almost every square foot of this property? It is this question that draws our attention to the mice as the major propagating vector for this plant.
More study is needed to investigate my hypothesis and GSWA welcomes any science student or professional who wishes to help us unravel the mystery.
Number three on the most wanted list of floral malefactors on our site is Japanese stilt grass. This woodland grass at first glance can be very beautiful in the way it carpets the herbaceous layer in a sea of verdant green. The operative word here is “carpet” — this plant is so invasive that it crowds out most every other herb and forbs in its path. The only technique that we use to deal with this nemesis is to manually pull it from the ground. This must be done before its seeds are ripe (July-Sept.) or all you are doing is helping the plant propagate elsewhere. Because this plant is virtually everywhere on this site we limit this activity to the deer enclosures and our trails. Scientists are trying to find a biological control and an herbicide that can be used to safely rid us of this insidious component of our woodlands. This is one plant that appears will be with us for a long time.
Last but by no means not least, number four on the most wanted list of floral trouble makers on site is the ever-abundant garlic mustard. This plant gets its name from the fact that when crushed it gives forth a repugnant odor reminiscent of garlic. Like most members of the mustard clan garlic mustard bears its seeds in elongated pods that, once ripe, explode out and can be broadcast a distance from the parent plant. As with stilt grass if you decide to remove while in fruit all you are doing is help the plant propagate. One of the first plants to bloom in spring, we try to pull it early. This has become one of the more important early spring tasks for our volunteers. After five years of this I am proud to report we have substantially reduced the occurrence of garlic mustard on the six acres west of the silver brook.
Garlic mustard is one of the most prevalent invaders to our eastern woodlands. You can find it in almost any soil type from wet to dry, full sun or shade, and it will do especially well in areas that have been previously disturbed. Because this plant is one of the first to grow in spring it is important to p ull it early so that our native spring ephemeral plants have a chance to fulfill their life cycle.
Unfortunately these four plants are not the only invasive plants on the site. The following is a list of plants that can be found on the property, are considered to be nuisance plants that have escaped from gardens, have been planted by government organizations for specific purposes, have found their way here through commerce, or have been inadvertently relocated through international travel:
- Dames rocket
- Tansy mustard
- Purple loosestrife
- Canada Thistle
- Calico Aster
- Crown Vetch
- Japanese Barberry
- Russian OliveReed Canary Grass
- Japanese Barberry
The GSWA Conservation Area is a microcosm of what ecologists consider to be a holocaust worldwide — the sterilizing of environments into a monoculture of a few species. Hawaii, New Zealand and Australia have some of the worst cases of invasive intrusions anywhere on earth, but all continents are now riddled with misplaced biota. Some may argue; who cares that their are only a few species where once many existed? How does that effect mankind? The answer to this question lies in the basic principals of ecological science — that all things have evolved over millennium and that genetic stability is strengthened by competition with others. When you supplant one species where many once existed you weaken the system’s ability to function efficiently, hence compromising ecosystems, free services of water and air purification. I like to draw the analogy of an ecosystem being the equivalent of a many-tiered scaffold where the supporting beams are tantamount to species. Sure you can remove a cross beam here and a vertical strut there and still have the scaffold support a person. The problem is that if you continue to remove beams at some unknown threshold the scaffold will collapse with disastrous results. Weakening an environment through the removal of species is the equivalent of playing Russian roulette with earth’s life support system.
The desperate situation the biosphere has found itself in can at times seem overwhelming and insurmountable, with so many foreign plants, animals and for that matter disease causing havoc worldwide. Like so many problems the answer lies in education to the cause — that’s what our efforts on the site are hopefully doing. If we can educate people to their connection with the earth and get them to be better stewards of their own backyards we may just beat the clock on the impending doom waiting to come to our environment.