Summer World: A Season of Bounty - Bernd Heinrich (2009)
Chapter 21. Silent Summer
I BREW MYSELF SOME COFFEE AND THEN LEAVE TO revisit Huckleberry Bog, a haven for many plants and animals that are not found in the forest. It is surrounded by forest and edged by a cordon of dense brushy thickets growing in algae-covered water. I don tough pants and a shirt when I need to force my way through, but I don’t wear boots—they get filled with ice-cold muddy water when I get to hip-deep holes or beaver channels. Wet cold feet are obligatory, and I put on worn-out running shoes. With some relief I finally break through to enter the bog proper, where I am in the open and walk on an ancient mat of roots and sphagnum (peat) moss that has grown over a glacial pond. Some of the same tree species that grow at the periphery are also present—red maples, black spruce, and larch. But here they are scattered and look stunted, like bonsai. As if I were walking on a waterbed, each footstep depresses the root and moss mat, and it sinks a few inches, to rebound when I lift my foot—hence the name “floating bog.” Somewhere still preserved in the solid bottom below me is the pollen of plants that grew on surrounding hills after the last ice age. Did a woolly mammoth or two break through and leave its bones here also? Except for the refrain of the yellowthroat and six other birdsongs, the bog remains silent. It does not tell. But a white-throated sparrow flushes near my feet, and I gaze into its nest cup, which is sunk into the wet moss. I admire four blue-green eggs spotted and blotched in reddish brown. What don’t I see? Where is the olive-sided flycatcher? It always used to be here, perched on the tip of a tamarack and repeating its loud clarion call that seemed like the signature sound of the bog. Where are the bumblebees? They are the only bees able to forage, and pollinate, many of the bog plants (as well as commercial berry crops) when the weather is cool or otherwise not suitable for other bees.
In the early haze on this cool morning, the bog’s open expanse is a study in rich greens and pastels. The overwintered needles of the stunted black spruce are bleached to a yellowish tinge from the previous summer’s fresh blue-green. None of their leaf buds have yet opened, although the tamarack, also a conifer, had shed golden yellow needles in the fall and is now opening all of its buds on its black-and-white lichen-encrusted twigs, revealing tufts of light bluish green needles. An intricate intertwined tangle of evergreen perennials—leatherleaf, swamp laurel, rosemary, Labrador tea, lambkill, and cranberry—rests on the sphagnum, and as my feet sink in I see small clumps of bright pink blossoms of the swamp laurel, and shining white ones of the rosemary. At the water along the edge grow the taller and deciduous plants—high-bush blueberries, huckleberry, winterberry, chokeberry, and privet andromeda—all now putting on new yellowish to bluish green leaves. The color combinations of the leaves, buds, twigs, flowers, and berries—greens, browns, yellows, red, gray, black—are artistically perfect. I pick a selection of the plant riches to take home so that I can make a token sketch. It can be only a reminder of the beauty and perfection of this place, a piece of work of the Creation.
Bumblebee queens have been out of hibernation for at least two or three weeks, and by now they would have found nest sites and would be starting their annual colonies. All the flowers that are concentrated here should be a magnet for them. But today, like the last time I was here, I hear and see almost none. Even after slogging all around the bog until my feet are numb from the cold, I again see none of the many species expected. I see only one Bombus vagans and one B. ternarius, the latter a pretty black, yellow, and orange bee. Has something happened to the bees?
One species, Bombus terricola, which used to be the most common one from my clearing in the woods to the tops of the nearby mountains, into this bog, and into the woods in the northern Maine wilderness, seems to be totally gone. I have not seen it for years, and I am again shocked not to see it today. I have seen few bees of any kind, however, and I am not yet worried, because bumblebee populations, like populations of other social insects, such as wasps and hornets, keep growing throughout the season. Each queen will produce hundreds of workers as the summer progresses. By July the population will appear to have dramatically increased, since the queens who before then spent most of their time hidden inside nests where they incubated their eggs and larvae have produced crowds of workers and drones. Thus, late summer is the best time to see which species are locally present. Bombus terricola was still present, though very rare. During two years’ search I ended up seeing three workers in Maine and one in Vermont.
On this day in May the bog looked pristine and nothing seemed changed except for the apparently total absence of a species that hardly anyone would have looked for, or noticed. What happened?
SOME YEARS AGO I FOUND ABOUT A DOZEN MOUNDS OF Styrofoam chips mixed with peat buried in the bog to grow something above the water level. I think they were the remains of potting soil for marijuana plants that someone had grown in the most hidden spot he or she could find. The foreign plants had long since been removed, but I was appalled to see a substance in this natural ecosystem that did not belong here. I spent half a day digging it up; hauling it out through the woods and up to the road; trucking it away; and paying to leave it at a dump, even though I was trespassing myself in the bog (since I had no idea who owned it). This time the bog was apparently no longer being used as a dump for piles of Styrofoam (mixed with soil), but on my walk I had passed a real dump site on the side of the hill toward the bog, and I was again shocked, angry, and—more than anything else—also afraid. This dump site contained an unsightly collection of plastic, other discarded petroleum products, dozens of tires, and other detritus. Could poisons be released from any of these products of our chemically synthesized civilization to bio-accumulate and disrupt the metabolism of an ecosystem?
Any foreign chemical put into the ecosystem, whether the woods, a swamp, or the body, is by definition guilty until proved innocent. And innocence is difficult to prove, since effects may be slow, may be long delayed, and may pop up in the least expected places. I am talking about natural versus unnatural compounds, although I do not mean that natural compounds are nontoxic. On the contrary, some of the most toxic chemicals known to man are produced naturally by plants and animals and usually serve as a defense. These need to and do have immediate and all too painfully obvious effects, but they do not accumulate in the environment as plastic does.
There is an incredible toughness to life, but at the same time a frailty that borders on the absurd. We supplement our milk with vitamin D, which we need for our health, but vitamin D is also used as a rodenticide. A polar bear has a huge amount of vitamin A in its liver, enough to kill a human who eats it. I think I have been especially sensitive to frailty versus toughness because of my experience in trying to keep wild animals as pets or to domesticate wild plants—to say nothing about trying to get them to reproduce. Almost invariably, for any one species there is a huge list of what seem like absurdly fussy requirements related to its natural environment, requirements that are often almost impossible to consciously duplicate.
One chemical, which seemed so nontoxic that people offered to ingest it, turned out to be deadly. This was dichlorodiphenyltrichloroethane, more commonly referred to as DDT, an insect poison that broke down to dichlorodiphenyldichloroethylene (DDE), the active culprit that affected birds. It took years for the effects of this toxin to be identified. The offending chemical first had to be passed on from one organism to another; in some of these organisms it did no discernible harm, but eventually it reached some which it did harm. It was slow-acting and did not directly affect the birds’ mortality. It affected their behavior, and the thickness of their eggshells—especially in pelicans, who ate fish that fed on aquatic invertebrates; and in raptorial birds, particularly falcons, because they ate birds who had eaten insects. Thanks to the alerts sounded by naturalists, and to long, patient, expensive sleuthing, DDT was eventually identified as the source of the devastation. Heroic countermeasures were instigated, and they reversed the trend toward what would otherwise have been the obliteration of more than I dare to contemplate. The scary part is that DDT was solemnly sworn to be a safe chemical—it had been extensively tested before being released. And now, many decades later, we are still finding out more: for example, that exposure of girls to DDT prior to puberty greatly increases their risk of breast cancer later in life. We still release about fifty new chemicals into circulation per week. They are tested on lab rats—animals that never experience summer or winter, that live well in dumps, and that when tested have no relation to any ecosystem except a sterile cubic plastic box. The chemicals don’t get tested in a pristine bog where the olive-sided flycatcher sings and the bumblebees collect nectar and pollen from pink rhodora blossoms in early summer, and where blue pickerelweed flowers poke up out of the water of the languid stream flowing through it in July and August.
In the summer of 2008, I finally saw Bombus terricola again. I found one dead in Hinesburg, Vermont, and in Maine I regularly saw several live ones in three places where I looked (Hog Island, in Muscongus Bay; in western Maine on my hill, and near Orland). A continuing comeback of the species is likely. I suspect now that its severe setback for over two decades could have been due to a “wildfire” effect; a very high former population was dense enough for an emergent or new pathogen to easily spread from one bee to another. The high bee population favored the lethality of the pathogen on those bees. If this is correct, the surviving bees will now have evolved increased resistance, and the surviving pathogens will have evolved reduced virulence. A dieback by chemicals, on the other hand, would likely have affected many species simultaneously.