Cold, rushing water splashes over boulders and logs and around my legs as I try to find footing on the slippery rocks of Steven’s Creek. In the upper reaches of this coastal mountain stream near Cupertino, a shield of alders and bay trees protects against the hot July sun, lowering the temperature by about ten degrees. Rays of light shine through openings in the canopy and enliven the otherwise dimly lit setting. Moving downstream through the fast-flowing water, I use the five-foot handle of my insect net as a walking stick and am grateful for the extra support. Then suddenly and from a distance, I see a Spiketail flying about a foot above the water, heading straight toward me.
“This dragonfly adds a note of mystery to the scene,” wrote Clarence Hamilton Kennedy, who surveyed dragonfly communities throughout California in 1914, “for the individuals with their strange ophidian coloration glide noiselessly up stream or down.” I swing the net and miss, feeling a twinge of disappointment, while the mysterious black and yellow dragonfly carries on aloof, “moving straight ahead as though drawn irresistibly onward.” Kennedy once lamented that the collector had only a single chance at a Spiketail. If so, I just missed mine. Whatever else has changed since 1914, the behavior of this species remains the same, which is unsurprising given that dragonflies have inhabited the earth for over 300 million years.
Kennedy was the first to carry out a comprehensive census of dragonflies in the western United States. While working on a graduate degree in entomology from Stanford in 1914-1915, he travelled by railroad as far north as Chico; as far east as Carlin, Nevada; and as far south as Los Angeles. He compiled lists of species at specific sites along with notes on environmental conditions. During that time, many naturalists were documenting biodiversity throughout the country, finding and describing new species, but detailed historical information for insect communities is rare. Kennedy’s work is a valuable source of information on freshwater habitats and insect communities at a time when widespread urban development was beginning, and more than 50 years before there was any thought of global warming. Aquatic insects often serve as biological indicators of freshwater ecosystem health. Shifts in the diversity and community composition of dragonflies in California and Nevada over the past century could indicate that similar changes are occurring in other aquatic insect groups and freshwater ecosystems as a whole.
I have been revisiting Kennedy’s sites to determine how dragonfly communities have responded to large-scale intensive land use, water regulation, and climate warming. Along the way, I also found myself comparing our personal, cultural and environmental experiences at each location. Accounts from six of the 44 sites that I have re-surveyed illustrate some of our shared experiences collecting and observing dragonflies within settings that are worlds apart. Both the Chico River, running through Bidwell Park, in Chico, and the relatively undeveloped Humboldt River, in Nevada, invoke a feeling of unity with the past, while the Truckee River, Lake Tahoe and Donner Lake, in the Sierra Nevada Mountains, remind me of how different our lives and environments have become. Steven’s Creek starts out, in its headwaters, relatively undeveloped but becomes a highly urbanized stream before it empties into the San Francisco Bay. Patches of habitat pop up as the stream meanders through city parks. To follow Kennedy’s footsteps nearly a hundred years later is to examine the world with a renewed awareness of surroundings and the passage of time.
At its headwaters, in the northern Central Valley, the Chico River runs through the center of Bidwell Park, where the original habitat is largely preserved. Here I encountered all the same species that Kennedy observed, and more. We both witnessed the Western River Cruiser flying above the water as if on a bomb run. Similar to the Spiketail in both appearance and behavior, this species flies straight up and down the river, only at much faster speeds. We both captured the Gray Sand Dragon, whose larvae live in sand-bottomed areas of streams. They burrow through the sand, just below the surface, so that their backs are covered, and thus avoid being carried away by the flowing water and shifting sands. The Pale-Faced Club Skimmer, which Kennedy described as the most graceful dragonfly he had ever seen, is also still flying in healthy numbers. He admired a female cutting figure eights through a swarm of small flies. This dragonfly is black with clear wings, a long, thin abdomen, and a large white dot on its bulbous, clubbed end. My heart skipped a beat when I saw one elegant individual flying toward me. Just as Kennedy described, this clubtail was indifferent to several passes of the net before I finally succeeded in capturing it.
Our experiences converged again along the Humboldt River, in Nevada, where not much seems to have changed over the past century – except for piles of old cars embedded in the riverbanks (in a town called Carlin, of all places). The river itself remains a muddy alkali stream with many tight meanders and loops. In Golconda, the Humboldt is so muddy that when I attempted to cross it I found myself waist-deep in muck. As detailed in his notes, this is where Kennedy first saw the Brimstone Clubtail, unfortunately flying away from him, and waited with great suspense to see if it would land or continue to fly out of reach. On hands and knees, he approached the rare clubtail, and, as he wrote, “was greatly relieved…to see that he, still unmindful of his danger, was busily engaged scratching his head with his foot.” Such accounts from the field are perfectly clear, involving no head-scratching on my part, after prowling the same sites and engaging in the same task as Kennedy. I have felt the same relief while successfully stalking a hard-to-catch dragonfly, and the satisfaction that comes from then capturing the gray-eyed and elusive Brimstone Clubtail.
Outside of protected habitat and relatively undeveloped regions like the Nevada desert, my experience differed significantly from Kennedy’s. The most obvious change since 1914 is the sheer number of people who live in or visit any given locale. The population of California, for instance, has increased from 2.7 million to 37.9 million people over the past 100 years. As a result, the traveler’s experience is now burdened by crowds and traffic, particularly in popular vacation spots such as Truckee and the Lake Tahoe area. Additionally, with the expansion of urban areas, agriculture and dams, freshwater habitat has become less diverse. Some aquatic species benefit from the introduction of lake-type habitat, retention ponds, canals and ditches in California, while many others do not.
Over the Fourth of July weekend, I found throngs of people floating down the Truckee River, some in yellow inner tubes with drink coolers attached, others in big blue rafts seating four to eight each. One party of around 40 people, all holding onto one another, made a long chain of floating donuts. After marveling at the spectacle, I bought a raft in Tahoe city and joined them. I started at the outlet of Lake Tahoe and floated down the river en masse with about 1,000 vacationers, although instead of drinking beer and sunbathing I was catching dragonflies— like the Four-Spotted Skimmer, Paddle-Tailed Darner, and Western Red Damsel. Kennedy would have been shocked to find such a scene. Those 1,000 people would have represented half of Truckee’s population in 1914, all floating down the river at once during a four-hour period. Today close to 17,000 people live in the town, and many more visit during the summer. While the total number of dragonfly species was essentially the same as in 1914, the percentage of generalist species (those able to inhabit a variety of pond, lake and stream habitats) increased from 41% of species along the Truckee River in 1914, to 63% in 2012, while specialist species declined from 59% to 37%.
Another aspect of life that has changed since Kennedy’s time is transportation, and it, too, has affected dragonflies. The Truckee River flows from Lake Tahoe, which has been a popular holiday destination since the early 1900s. I traveled there in my car from Berkeley along two to four lane roads, at an average speed of 70 miles per hour. The entire journey took about four hours. In 1914, limited transportation through the mountains made it much more difficult for travelers who, like Kennedy, took the railroad to Truckee and then made their way to the lake. The road connecting southern Lake Tahoe to the western shore of the lake – what is now Highway 89 – was just completed in 1913, after months of dynamiting granite out of the mountain slopes. Originally, this rough one-lane road only supported light traffic— open-air Model-T’s and Oldsmobile’s with a top cruising speed of 30 miles per hour. Kennedy explored the lake itself aboard a steamer, as did most vacationers at the time.
Such conveniences have not come without a cost. Although today Lake Tahoe is world-renowned for its clarity, it was even more majestically clear during Kennedy’s time. Dust from the very roads that make traveling to Tahoe easier, allowing more people to live and travel here were a major factor in degrading the lake. Aboard the steamer, Kennedy observed fish 20 feet below the surface and noticed distinct scratches of paint on the keel, so that looking over the boat deck gave him the feeling of “floating on air.” He must have been delighted when, in Emerald Bay, a single Great Basin Snaketail flew aboard the steamer, considering that the nutrient-poor lake generally supports little aquatic vegetation or insect life. This multi-colored species is about 50 mm long with a big blue eyes, yellow face, olive-green thorax, and yellow triangles atop each of its ten abdominal segments. White adorns the sides of the abdomen tip where it flares out into a club-shape. I did not see the Great Basin Snaketail at Lake Tahoe, or anywhere else for that matter.
Many other stream and lake-breeding species are less abundant and more narrowly distributed today than they were in 1914. Several of them, including the Great Basin Snaketail, belong to the clubtail family, Gomphidae, named after their club-shaped abdomen. About 40 miles northeast of Emerald Bay, Kennedy hit the jackpot with this species, catching over 100 Snaketails on the fine-gravel beaches of Donner Lake. He then caught 80 Pacific Clubtails, also a common clubtail species in his time, while I caught only one—the only one I saw during two days of collecting. The shoreline habitat has been eliminated or drastically changed—by a road and docks along the northern length of the lake and vacation homes right on the water on the south. As a result, the two clubtail species that once thrived in this habitat are no longer present or they are rare.
Back at Stevens Creek County Park, after missing the first Spiketail in the upper reaches of stream, I soon saw another one. This individual, like the first, made its way up the stream without regard to my presence and, to my great excitement, I nabbed it. Then, I saw another…and another, until I realized that this beautiful snake-like dragonfly was abundant here in the headwaters during this time in the season. I had sampled here twice before, earlier in the summer, and this was the first time I saw it. With the Spiketail, I had caught all the same species that Kennedy observed here in 1914.
Eventually, Stevens Creek settles down onto a flatter terrain and winds its way through Cupertino and Mountain View before emptying into San Francisco Bay. The heart of Silicon Valley and the “Dot-com” boom, this area of the stream has become highly urbanized in recent years. The surrounding neighborhood is covered in concrete and buildings. In general, as large regions become urbanized or converted to agriculture, the diversity of aquatic habitats declines. Dragonflies reflect habitat homogenization and their communities also become more similar across individual sites. Habitat generalists thrive and expand, because they can survive as long as there is water and some aquatic vegetation, while habitat specialists decline in abundance or in the extent of their distribution with the loss of their particular type of bog or stream habitat.
As I visit the creek in a Cupertino park, bright orange Flame Skimmers chase one another playfully, and cherry-red Cardinal Meadowhawks perch upon Tule reeds. This small patch of habitat is alive with dragonflies. Sure, they are not the same species that Kennedy encountered – all are fairly tolerant to habitat change and pollution—but they are still wonderfully charismatic. They are an eye-catching sign that life is possible in urban streams, as long as vegetation grows on the banks and in the water channel, with areas of open canopy that let the sun shine on the water. The vitality of ecosystems in many urban areas is limited, to be sure, and they will never be the same as in the past. But a good starting point to restoring urban streams is converting concrete-covered water drainage systems back into habitat for these vibrant insect predators. It helps that humans can relate to the big eyes and personalities of dragonflies, and can enjoy their activity on a pleasant stroll through the park. All the while, the charming red, blue, orange, white, spotted, green and purple individuals dart through the sky, and from reed to reed, eating mosquitoes.
Most of Kennedy’s specimens and his field notes are currently located in the Museum of Zoology at the University of Michigan; special thanks to Mark O’Brien for his assistance with this material. Kennedy’s species lists and notes are formally detailed in “Notes on the Life History and Ecology of the Dragonflies of Central California and Nevada” (Kennedy, 1917). Some specimens are also held in the California Academy of Sciences, the United States National Museum, the Essig Museum of Entomology, and the Florida State Collection of Arthropods.