By Michael Adamovic
ASK A PERSON WHO’S RECENTLY TAKEN A STROLL or a hike through the woods what the best part of their trip was, and the answers that often come up are spotting wildlife or reveling in the beauty of the woodland wildflowers. While we all love and appreciate the splendor and magnificence of trees, the flowers growing beneath their shade, with their flashy and colorful blossoms are apt to garner more admiration. And, unlike a chance encounter with wildlife, flowers are ubiquitous and regularly enjoyed in every season except the harshness of winter. But, while many of these showy species abound in stable forested habitats, they’re not as robust as one would imagine. They may seem hardy but are actually incredibly fragile, their very existence stacked atop a number of variables, which if not perfectly balanced, will topple the same as a pitted Jenga tower. It’s really a miracle they exist at all. It’s no surprise that the moment their forested environments begin to be destabilized by invasive species, logging or fragmentation by development and sprawl — and now frequently a combination of all three — these wonderful plants inevitably decline, causing a dramatic shift in the once diverse species composition.
On a recent spring visit to an opulent and spacious old-growth forest in the Adirondacks, I was reminded of just how vital these intact woodlands are to the integrity of flowering herbaceous species. Never having been logged, or seriously disturbed in any way, the land was absolutely pristine and useful as a tool for comparison in terms of biodiversity to compromised habitats. This was a place of massive and venerable trees, mixed among mid-aged individuals and saplings situated in an environment rich in vast quantities of fallen woody debris in various stages of decay, all sitting atop beds of delicate ferns and damp, verdant moss. These intertwined idyllic features are more than just aesthetically pleasing. Many wildflowers rely on these features for survival.
The best known spring ephemerals, for instance — Dutchman’s breeches, trilliums and bloodroot, among others — require a continuously damp substrate in order for their seeds to germinate. If these recalcitrant seeds happen to dry out, they become rather useless. A dense overhead canopy helps prevent moisture loss to the forest understory from the desiccating influences of direct sunlight, along with reducing subcanopy temperatures. Additionally, spongy mosses, like those I witnessed scattered throughout the Adirondack forest, slowly release water to the soil like miniature reservoirs. In sunnier and drier locales where moss has difficulty growing, thick layers of leafy duff will similarly do the trick. What’s more, these plants use a clever seed dispersal tactic known as myrmecochory, where ants are the primary agents of the distribution process. Elaiosomes, tiny lipid- and protein-laden appendages wrapped around the seeds, entice the insects to collect and bring them back to their nests where the fleshy appendages are removed and consumed. The remaining seed bodies are then dumped in nutrient rich waste pits optimal for germination. While effective in transporting seeds away from the parent plant, employing such diminutive creatures results in seeds rarely travelling more than a handful of feet. As such, populations expand quite slowly and are generally localized.
Slightly after the earliest of the spring ephemerals make an appearance, red columbine, with its red and yellow chandelier-like blossoms, erupt in flaming fury along exposed rocky slopes. These flowers are comprised of five long tubular structures, at the very end of which is located the nectar-reward for pollinators. The problem with these tubes is that only creatures with the longest of tongues can access the nectar — namely hummingbirds and bumblebees. Columbine has evolved to exploit a narrow niche, mainly meant to favor the dainty hummingbirds. The color red is well-known to attract these birds. Growing on bedrock outcroppings and steep cliffs, where dense trees and shrubbery can’t gain a foothold, ensures the flowers are easily spotted and accessible to the rocketing birds, which prefer to zip along unencumbered, a result of a high metabolism that requires them to always be seeking another flowery meal without a moment’s rest.
The point I’m trying to make here is that habitat loss doesn’t just destroy flowers in a physical sense, it destroys plant reproduction processes by eliminating important pollinators and seed dispersers from an area. How can the outlook for these wildflowers’ continued existence be anything other than bleak in a habitat devoid of beneficial organisms such as pollinators?
More finicky than the spring ephemerals — and perhaps any other group — the most beloved of our wildflowers, the orchids, are fast declining. To say they are picky is a grand understatement. Most orchids have an extremely narrow set of acceptable growing conditions. Undoubtedly the most important factor to their establishment is the presence of certain soil fungi. All orchids at some point in their lives rely on the symbiotic relationship they form with mycorrhizal fungi. The dust-like seeds of orchids lack endosperm, which in most plants provide seedlings with sustenance early on (think of an acorn). But for orchids, in order for an embryo to develop, seeds essentially need to become infected by a fungus. This “infection” is benign, in fact beneficial, with the seeds now being supplied with the necessary nutrients for successful germination. Later on as the orchid matures, the original investment of the fungus will be paid back with sugars produced by the plant’s photosynthesis.
Not just any fungus will do. Many orchid species have evolved to rely only on closely related fungi from a particular genus, and, in some cases, such as when it comes to lily-leaved twayblade, a single species. So, if the correct fungi are absent from the soil, even if all other conditions are properly met — the site having the correct habitat type, soil pH, moisture regimes, light conditions, etc., — the seeds will never sprout. Thus, when we actually find an orchid growing and thriving, it truly is in the “perfect” spot.
Even the slightest changes in the environment can adversely affect these fragile plants, even once established. While some orchids rely on fungi only during the early stages of life, numerous species keep the mutualistic association going throughout the entirety of their lives. This is why transplanting is futile. If removed from its fungal partner, much-needed nutrients delivered by the fungus to the orchid disappear, and the plant slowly withers. The valuable connection is almost never reestablished, the correct fungi rarely being present at the new site.
Likewise, if fungi happen to vanish from an ecosystem, the identical consequences inevitably result. The same fungi that support orchids are they themselves dependent on select tree species for similar mutualistic relationships. When forest tree composition changes, these pivotal fungi sometimes vanish. Large-scale disturbance, either natural or influenced by anthropogenic factors, can shift a habitat composed of mainly shade-tolerant climax forest species (sugar maple, beech, hemlock) to shade-intolerant pioneer trees (aspens, yellow poplar, white pine), in the process typically lowering diversity. A severe disruption of the canopy allows for shade-intolerant species to gain an edge until the forest completes the lengthy process of forest succession. Centuries may pass before we see the forest restored to its original composition of both trees and herbaceous species. In the meantime we can say goodbye to the rich diversity of orchids many mature, or climax forests, support.
Nicknamed the “rarest orchid east of the Mississippi,” the federally threatened small whorled pogonia is dependent on fungi that form a bond primarily with oaks, hickories and American beech. It typically inhabits moist environments on moderate slopes or occasionally at their base, which possesses a tough, impermeable upper layer of soil, known as a fragipan, that causes water to flow downhill similarly to the movements of a water slide, rather than soaking vertically into the soil. While tree species can be replaced with comparative ease, the obliteration of topographical and other abiotic features cannot. Destruction of a hill, disruption of a delicate microdrainage or the homogenizing of soil all lead to the same result. It’s worth repeating that these organisms’ lives, unlike those of weeds, aren’t robust — pull out a rivet or two, 10 or even 50 from a bridge and the structure will probably still stand. Orchids, such as the fragile small whorled pogonia, can be undone like a house of cards by even the smallest breeze or exhalation.
In terms of delicateness, parasitic plants face similar issues. Completely lacking chlorophyll in many instances, these oddities of the plant world cannot produce their own food, and instead must acquire it by pilfering the supplies of nearby trees. Some plant parasites, such as the ghostly Indian pipe and softhued pinesaps, form associations with fungi. While these interactions are of a mutualistic nature like that of the orchids, they use the fungi as an intermediary to steal carbohydrates (sugars) directly from trees without providing anything in return to their arboreal hosts. Others, like beechdrops and squawroot, tap directly into tree roots extracting what they need to survive.
Beechdrops, as the name suggests, are reliant solely on beech trees for survival. This group of herbaceous plants normally cause little damage to their hosts, a result of their comparatively small size. Parasitic plants are not equivalent to some insidious tapeworm, which only benefit themselves. A more apt comparison would be referring to them as a sort of Robin Hood. Apart from flowers providing resources to hungry insects, squawroot is regularly consumed by bears. Their springtime diet is typically composed of 10 percent of this strange, fungus-looking flower. In some southern reaches, this number is much higher; in Shenandoah National Park, it’s been shown that squawroot may constitute up to 40 percent of a bear’s diet in the lean months. It’s also quite important to deer and other smaller wildlife.
As we have seen, all the wildflowers just described can’t simply move elsewhere. Those that can, we frequently refer to as weeds, or worse — invasive species. Most of the flowers of our forests are of a different brand, evolved to exploit a so-called “stable-habitat” scenario. These longlived perennials put most of their energy into building tissue, such as large taproots to store energy, rather than devoting the lion’s share to the development of seeds. As a result, they can take many years to mature and are especially vulnerable to exploitation.
In complete contrast to lush and speciesrich old-growth, or of slightly younger, yet healthy maturing forests, a significant percentage of our secondary- growth forests are remaining indefinitely in a sickly adolescence devoid of any remarkable beauty. Invasive species proliferation is mainly to blame. Instead of regenerating to a climax state, non-native trees and shrubs, and even herbs, are mercilessly smothering native species, preventing a complex multi-tiered canopy and understory from developing. Japanese barberry, for example, is especially harmful to spring ephemerals. This thorny bush leafs out earlier than just about any other shrub or tree in eastern forests, prematurely shading out species that evolved to awaken early to exploit the abundance of vernal light reaching the understory. Instead of forest floors carpeted by picturesque arrays of trout lily or bloodroot, we have dense and oppressive monocultures of the ubiquitous garlic mustard, smartweed, Asiatic dayflower and Japanese stilt grass.
Walking through places infested with invasives is a heart-dampening experience. What should otherwise be colorful and cheery is anemic and lackluster, all because we altered, or might I say, desecrated the landscape. Healthy ecosystems are normally able to repel foreign invaders. But, loosen the soil, add a dose of bright light and eliminate our native defenders, and our forests are easily conquered. Encountering a vibrant wildflower pushing itself through the detritus of the forest floor on a cold spring morning can make all the difference to our day. We should preserve what we can. As Thoreau sagely put it, our forests and all they contain are “more to be admired and enjoyed than used.”
Mike Adamovic works at One Nature, LLC overseeing habitat restoration projects in southeastern New York, in addition to managing his photography business, Adamovic Nature Photography. He is the author of “Hudson Valley Reflections: Illustrated Travel and Field Guide” set to be published in July 2017.