Silent Springs and Fruitless Falls

The Impending Pollination Crisis

STEVE REMEMBERS:

The Virgin River basin of southwestern Utah is a place of rarities, from towering crimson canyon walls and Joshua trees to a host of low-lying, lesser-known living treasures. It was my first time to the Virgin, but Gary had made pilgrimages here before, collecting rare wild sunflowers to be used in breeding disease resistance into commercial hybrid sunflower crops. This trip, however, we came to the Virgin not for its sunflowers but to stalk a rare diminutive poppy. That poppy grew on gypsum-laced bluffs and hummocks too bleak for much of anything else to grow, but it had one local animal associated with it that we hoped to meet—a bee as rare as the plant itself.

We had flown into the virtual-neon-baking-hot reality of Las Vegas one morning in late spring. There we rented a vehicle to take us two hours to the northwest, into the higher reaches of the Virgin watershed where the crimson cliffs of the Chinle Formation enclosed sandy valleys. Below us, in one valley, a patchwork of greener-than-green alfalfa fields juxtaposed themselves against the badlands of pink dunes, cocoa-colored mudstones, and pale gray, bleached-out gypsum hummocks. From the very base of the nearby cliffs, low-growing familiar shrubs of pungent creosote, snakeweed, and saltbush were sparsely dotted across the flats, their roots competing for the meager rainfall of that semi-arid land. It seemed like an unlikely spot for us to look for one of the most endangered pairs of plant and animal in all of North America, but our hunt was on.

The poppy in question has a lovely, ivory-colored blossom, but a name that few people have heard: Arctomecon humilis. One animal associate of the "bearclaw" poppy is recognized by even fewer people, for it is a bee recently described as a new species: Perdita meconis. The story of their barely surviving together in a not-so-virgin habitat is a reminder of how little we know about the rarest-of-the-rare, even in a nation that spends more on environmental monitoring and protection than any other country in the world.

It could be that the bearclaw poppy was never widespread nor naturally abundant. Nevertheless, it has become exceedingly rare over the last century of habitat degradation, and the last decade of frequent drought. It was listed as a federally endangered species in 1979. Soon after that, during a five-year dry spell, nearly every seed-producing poppy plant died off, and hardly any new seedlings were recruited to replace them. Most of these perennials live a scant five years at the most, but far less than that when stressed. By the late 1980s, bearclaw poppy numbers had become so thinned that the conservationists who knew it best could only predict that it would be extinct by the year 2000.

We arrived at the end of a wet spring, so the prognosis did not look so bleak to us. Still, Gary and I wandered up and down the mudstone and gypsum hummocks of the Moenkopi Formation for well over an hour before I stumbled across the first flowering poppy. Excitedly I yelled for Gary to come over, for I doubted that he could see it from any distance away: it was barely 6 inches tall, with waxy blue leaves. The flowers bore velvety white petals and a central mass of bright orange-yellow stamens, looking like a miniature fried egg, sunny-side up.

We looked around, and realized that we were in a broad arc-like swath of a hundred poppies or more spread over 50 yards or so. Most of the plants had finished flowering, but the bulk of them had bloomed later than usual, so we were lucky to see quite a few blossoms. In fact, we were lucky to see any poppies at all. Cattle hoofprints and off-road vehicle tracks wandered right through the largest patch of poppies, despite a plethora of formidable signs posted nearby warning that the area was closed to traffic.

The abundant rains had encouraged high fruit production for the coming season, but when I knelt to examine the fruit, I realized that good weather was not enough to ensure that the fruits would contain a full complement of seeds. Each partially opened fruit looked like a miniature Easter basket, complete with handle, holding the seeds until they could germinate with the summer rains. A fully pollinated fruit might have over 30 thick, shiny black seeds in it. Yet many of the fruits that I scanned were already shrunken from lack of pollination, or perhaps from abortion resulting from the poor nutritional condition of the mother plant.

We took no seeds from the site, but we could easily count their numbers in the earliest-maturing fruits. They had just begun to dehisce, drying and splitting in fissures. A few fruits had 25 to 30 seeds in them, but most had far fewer. I rattled off my counts to Gary: 23, 20, 12, 14, 7, 18, 1, 4, and 11 seeds per fruit. Either many of the plants lacked the nutritional reserves to mature all the ovules into viable seeds in their fruits, or their flowers had not been pollinated to begin with: the average fruit held less than half the maximum seed complement it could produce under optimal conditions.

The only potential pollinators we saw during our dawn and dusk visits to the poppies were introduced honeybees, likely from a nearby apiary. They were busy on evening primrose and buckwheat blossoms, and for the most part, they left the bearclaw blossoms alone. Native pollinators may have been more active on this site earlier in the season, but they were nowhere to be seen while we were present over a two-day period.

Fortunately, in 1988, a group of entomologists from Utah State University had better luck at the site than we did. In May of that year, Vince Tepedino, a USDA-ARS research entomologist stationed in Logan, Utah, encouraged his student assistant Bonnie Snow to collect at the site. Bonnie swept up a species of solitary bee hitherto undescribed by entomologists, one that had evaded notice for more than a century after the poppies themselves had been described by biologists.

In fact, the bee had been collected just once before, on another kind of poppy, in the Kelso Dunes of eastern California well over a hundred miles west of the Virgin River. Terry Griswold was the collector of the Kelso Dunes bee, and when he saw that Bonnie Snow brought the same kind into his lab, he realized that these...