Incredible plants: giant sequoia

General Grant tree in the Grant Grove, Kings
Canyon National Park, 2014.

California is a land of superlatives, and especially so botanically. Trees are at the top of the list for California’s record breaking plants: the state is home to the world’s oldest trees (the bristlecone pines, Pinus longaeva), the world’s tallest trees (coast redwood, Sequoia sempervirens), and the world’s largest trees by volume (the giant sequoia, Sequoiadendron giganteum). Each of these record-setting trees occurs in different geographic areas and environments among California’s diverse set of geologies and climates. They are all conifers, a widespread group of gymnosperms (gymnosperms are seed-bearing, but flowerless, vascular plants).

The giant sequoia has a narrow geographic range, found solely on the western slopes of the Sierra Nevada range in central California. It occurs across a fairly broad range of elevations (825-2700 m), though most populations of the species lie between about 1800 and 2100 m above sea-level (Yu et al. 2017). Upper and lower elevations of the species may be limited by low temperatures and low precipitation respectively. The coast redwood is distributed in the coast ranges from central California to southwest Oregon. It typically grows at much lower elevations than the giant sequoia and generally in close proximity to the coast with its cool and foggy maritime air.

The coast redwood is believed to be the closet living relative of the giant sequoia. Both species are classified in the conifer family Cupressaceae which includes cedars, junipers, and cypresses. Metasequoia glyptostroboides (the dawn redwood), which occurs in China and was only discovered within the last century, is a cousin to the two California redwood species. Fossil evidence suggests that redwood-like trees were formerly much more widespread in distribution across the Northern hemisphere. Sequoiadendron for example, may have been distributed in the past in North America, Europe, and New Zealand. Thus, these three redwood species might be considered relict species with greatly constricted modern distributions relative to the past. Perhaps glacial cycles (increased northern latitude ice cover implicated in the case of Metasequoia) and other factors over time have led to the range constriction of this group of conifers.

Hypothesized evolutionary relationships among giant sequoia (Sequoiadendron giganteum), coast redwoods (Sequoia sempervirens), the dawn redwood (Metasequoia glyptostroboides) and other Cupressaceae. Tree after Kusumi et al. 2000. 

The giant sequoia is a behemoth, estimated to be greater in volume than any other tree species in the world. The largest individuals have an imposing presence in the mixed conifer forests in which they occur. The base of the trunk in the largest individuals can often reach up to 11 m in diameter and 90 m in height (a little shorter than the coast redwood). The giant sequoia has reddish fibrous bark like the coast redwood, with deep furrows evident in older, larger trees. Old growth individuals may live several millennia.

Needles and cones in the giant sequoia and coast redwood are different enough to enable easy identification (in addition to differences in native range between the species). The giant sequoia has short pointed leaves that emerge from stems in a radial fashion, whereas most leaves on the coast redwood are pinnate sprays of leaves flattened in one plane. (An interesting exception is the leaves at the very top of a coast redwood which look quite similar to giant sequoia leaves in overall form.) Giant sequoia trees have both male and female cones on the same individual. Female (seed-bearing) cones of Sequoiadendron and Sequoia are both egg shaped and similar in morphology, but cones of the giant sequoia are about twice as large, almost the size of a chicken egg. Female cones of the giant sequoia are produced in clusters high in the foliage and bear small papery seeds a few centimeters in size.

Foliage of giant sequoia (left) and coast redwood (right). Photos from Bearskin Grove, Sequoia National Forest (2014) and Ventana Wilderness, Los Padres National Forest, Big Sur (2015).

Female cones and seedling of giant sequoia, Tuolumne Grove, Yosemite National Park, 2017.

Several giant sequoias with other conifers in the
Tuolumne Grove, 2017.

Fire is a necessary ecological disturbance for the persistence of the species. Unlike coast redwoods which can grow semi-clonally (e.g., from burs), sequoias generally only produce new individuals from seed, though new shoots can develop from injured stumps in younger trees. Mature trees are resistant to fires of low to moderate intensity which remove understory plants and favor sequoia seed germination by exposing bare soils for germination and increasing light levels reaching the forest floor. When occurring in mixed conifer species forests, sequoias are often found with sugar pines (Pinus lambertiana) and white firs (Abies concolor). Lack of fire will promote white fir relative to giant sequoias.

Controlled fire is used today by some agencies to manage sequoia groves. Reducing woody biomass in the forest understory is a means of protecting groves from more intense large scale-fires made more likely by decades of fire suppression practices in the western US. 

With its immense size, the giant sequoia was a prized timber species in the 19^th century. Many of the 67 groves of living giant sequoia are currently protected on state or federal land. This includes three groves in Yosemite National Park and many groves in Sequoia and Kings Canyon National Parks. Additional groves within Sequoia National Forest were protected from commercial logging (which occurred up until the 1980s) with the creation of Sequoia National Monument in 2000. The groves vary greatly in size, old-growth forest extent, and logging history. The smallest of all groves is also the most northerly grove in Placer County west of Lake Tahoe. It has only 6 trees.

Panorama of the Muir Grove in Sequoia National Park, 2014. The sequoias are clustered at top center and can be distinguished from other conifer species by their slightly yellow-brown color and bushy crowns.

Sequoias are vulnerable to root disturbance and intense fires. Climate change might also present challenges to the species persistence, possibly through increasing drought impacts in the future in the Sierra. For instance, recent work by Yu et al. (2017) suggests that drought impacts may be more severe in sequoia groves than in nearby forests dominated by other tree species. However, Willard (2000) suggests that groves have been doing well recently, with many recovering from historic logging and some expanding in size.

References

Baldwin BG, Goldman DH, Keil DJ, Patterson R, Rosatti TJ, Wilken DH. 2012. The Jepson Manual. Vascular Plants of California. 2^nd ed. University of California Press, Berkeley, CA.

Eckenwalder JE. 2009. Conifers of the World. The Complete Reference. Timber Press, Portland OR.

Kusumi J, Tsumura Y, Yoshimaru H, Tachida H. 2000. Phylogenetic relationships in Taxodiaceae and Cupressaceae sensu stricto based on matK gene, chlL gene, trnL-trnF IGS region, and trnL intron sequences. American Journal of Botany 87:1480-1488.

Su Y et al. 2017. Emerging stress and relative resiliency of Giant Sequoia groves experiencing multi-year dry periods in a warming climate. Journal of Geophysical Research: Biogeosciences 122:3063-3075. Preprint link.

Weatherspoon CP. 1986. Silvics of giant sequoia. In Weatherspoon et al. Proceedings of the workshop on management of giant sequoia; May 24-25, 1985; Reedley, California. USFS General Technical Report PSW-95.

Willard D. 2000. A Guide to the Sequoia Groves of California.Yosemite Association, Yosemite National Park, CA.

Sequoias in the Muir Grove, 2014.

Cluster of female cones (left) and close-up of trunk (right), Tuolumne Grove, 2017.

The value of biodiversity

A controversial opinion piece on extinction and biodiversity conservation was published Thanksgiving week in the Washington Post by an evolutionary biologist. In the last few days, scathing assessments of the op-ed came across my Twitter feed, but I avoided the article until today. I finally dove in, and here are a few thoughts that emerged during the time I could muster on a Sunday evening.

Diverse assemblage of flowering plants in the understory
of a montane forest in the John Muir Wilderness,
California, summer 2017.

In the op-ed R. Alexander Pyron argues that “extinction is the engine of evolution”, states that almost all species that have ever lived on Earth have already become extinct, and notes that extinctions are inevitable for all currently living species. He argues that despite the loss of a species “the world will be none the poorer from it”. From this assortment of assertions (some obviously true like the inevitability of eventual extinction of all species), he then goes on to build a case that conservation is only prudent in-so-far as it benefits humankind.

In taking a rather extreme view of the role of conservation, the visceral reaction of many biologists to publication of this op-ed in a major media outlet is understandable. But does the author miss the mark? I think so on several major fronts:

1. The author paints an incomplete and superficial view of evolution and the production of biodiversity. Succinctly put, extinction is not the “engine” of evolution as the author claims. Rather, natural selection is the mechanism of evolutionary change, and as another evolutionary biologist S. Claramunt points out in a rebuttal, natural selection operates at the population level, not at the species level that Pyron discusses. Natural selection is one of the key processes of microevolution, which involves the generation of genetic variation within a species (novel genotypes and phenotypes) and its subsequent persistence or demise in the next generation by selection. This initial step in microevolution – the generation of genetic variability such as by mutation or genetic drift – is inherently a creative process, albeit a mostly random and inefficient one. In this light, the two major steps of microevolution (generation of variability and environmental selection) are both productive and destructive. Claramunt and Caroline Tucker address other controversial statements by Pyron here and here.

Where Pyron may be partially correct about extinction is its role in producing biodiversity at the macroevolutionary level. As one example, he cites the radiation of mammals and birds following the global mass extinction that wiped out the dinosaurs. However, while extinction may be an occasionally helpful mechanism for promoting radiations of new lineages over geologic time, it is certainly not necessary to generate new species. Speciation, on the other hand, is requisite for the creation of new biodiversity, and it can proceed easily enough in the absence of extinction through allopatric or sympatric mechanisms. A report just this week suggests the very rapid evolution of a new finch species in the Galapagos stemming from a hybridization event. Many species form from others without the parent lineage going extinct, increasing biodiversity. Moreover, when one surveys the history of life on Earth, despite messy fluctuations over geologic history, there may be more biodiversity today than during any geologic era of the past. For a net increase in global diversity to occur over the long term, long-term speciation rates have been greater than extinction rates. If anything speciation is the “engine” of evolution.

2. Though Pyron advocates for conservation if it serves a direct human need, the extent of species he seems willing to advocate for probably falls far short of the number really needed, even from simply a utilitarian point of view. The problem here is obvious: any argument about selective conservation of a smaller fraction of species fails to recognize the unknown inter-dependency of species in all ecosystems. What of the undiscovered connections and dependencies in the global web of life of which we are still woefully ignorant as ecologists? What of species that hold future drug discoveries, or that will only in the future be discovered to be critical to the persistence of other species or even the functioning of whole ecosystems? Even if impending extinction provokes difficult conservation decisions about which species to save in the future, those decisions need to be informed by understanding the ecological roles of the species and the relative loss of services that could result from extinction. I posit that we presently know very little about the ecological roles of the vast majority of species to be able to effectively triage our conservation efforts.

This notion of the interdependency of life is not just the poetry and song of nature lovers. Rigorous empirical research manipulating biodiversity levels at smaller spatial scales over the last two decades demonstrates that biodiversity often matters in order to sustain ecosystem productivity, stability, or other services upon which humankind depends (Cardinale et al. 2012, Lefcheck et al. 2015). Put simply, a grassland with two or three species is not the same as one with several dozen species; that extra plant biodiversity has measurable effects on the functioning of the grassland ecosystem. The importance of biodiversity for ecological functioning extends to genetic diversity within a species (Hughes & Stachowicz 2004), and by extrapolation (though we cannot experiment on continental or global scales) also reasonably extends to the whole biosphere: global diversity sustains a global suite of diverse ecosystem functions. A prudent, precautionary approach is to conserve as much global biodiversity as possible.

3. Finally, the op-ed fails on the ethical front. I won’t argue from a particular religious or philosophical point of view here, but rather simply from a humanistic one. To appreciate, conserve, and cultivate biodiversity is an inherently human experience. We need look no further than zoos and gardens to understand our intrinsic desire to connect with other species. As much as Homo sapiens is a destructive, warlike, compulsive, and competitive species, we are also inherently caring, empathetic, altruistic, and prudent. Biodiversity enriches our human experience, spiritually and aesthetically. And conservation of a mere fraction of Earth’s species upon which we are most dependent for food and shelter will not satisfy that enduring need for connection to the biosphere. Pyron’s anthropocentric arguments about conservation were taken to an extreme in the op-ed, and in so doing that viewpoint paradoxically harms our species by artificially disconnecting us from our deep human need for biodiversity.

The global, bipartisan efforts we put towards conservation, towards preservation of wilderness, towards city and national parks attest to the value we place on the conservation of other species. We cannot escape the deep connection (the “biophilia” of E.O. Wilson) that we have as humans to other forms of life. Though they lived long before the term “biodiversity” was coined, naturalists such as Humboldt, Haeckel, and Muir intuitively assessed the interconnected nature of life through observation of the natural world (Wulf 2015). Muir understood this dependency of all species on each other and asked a powerful ethical question useful as an antidote to an overly anthropocentric view of the value of biodiversity: “Why ought man to value himself as more than an infinitely small unit of the one great unit of creation?”

References

Cardinale et al. 2012. Biodiversity loss and its impact on humanity. Nature 486:59-67.

Hughes AR,  Stachowicz JJ. 2004. Genetic diversity enhances the resistance of a seagrass ecosystem to disturbance. Proceedings of the National Academy of Sciences 101:8998-9002.

Lefcheck et al. 2015. Biodiversity enhances ecosystem multifunctionality across trophic levels and habitats. Nature Communications 6:6936.

Wulf A. 2015. The Invention of Nature. Vintage Books, New York.

Yosemite VI: Wapama Falls at Hetch Hetchy

Our final Yosemite destination last weekend was Hetch Hetchy, my second visit to this remarkable and controversial valley at the northern end of Yosemite National Park. The valley is beautiful despite the reduction in its dimensions and grandeur by the controversial decision to build a dam and flood the valley a century ago. I cannot help but feel some sadness over that outcome, one that John Muir vigorously opposed in his last days. Only he and others of that era saw the valley before it was drown to satiate San Francisco’s thirst for water. I can only hope that the valley will be restored someday, with the water supply and hydroelectric energy the dam provides being provided elsewhere, though that presently doesn’t seem politically or legally likely.

Farther up the valley, beyond the reach of the dam lies an area of the park known as the “Grand Rapids of the Tuolumne River”, a backpacking destination that I hope I can visit someday. Backcountry wilderness trails crisscross the area to the north and south of Hetch Hetchy.

Crossing over the dam and through a tunnel blast into rock, a trail starts at the northern end of the reservoir heading along the west rim of the valley. The vegetation along the slopes is as much chaparral and shrub as forest, with manzanita, bay laurels, and oaks in abundance. At the four km point from the parking lot one reaches Wapama Falls which crashes down a steep granite face at the northern end of the valley. There are some pools near the base of the falls before it descends a bit further to reach the reservoir. Though not many plants are in bloom at this season in Yosemite, the rocky wetland gardens where the trail crosses the falls had a population of small attractive bright yellow flowers of the monkey flower genus Mimulus.

Wapama Falls on the north side of the Hetch Hetchy valley in the spring of 2011 (left) and fall of 2017 (right).

Flowers of Mimulus floribundus near
pools at the base of Wapama Falls.

Hetch Hetchy has been described as a companion valley to the much more famous and visited Yosemite Valley to the south. John Muir described it thus: “…it is a wonderfully exact counterpart of the great Yosemite, not only in its crystal river and sublime rocks and waterfalls, but in the gardens, groves, and meadows of its flowery, park-like floor”.

Views of the Hetch Hetchy Valley today from the north rim of the valley. At right
in center of photo is Kolana Rock.

Presently it is hard to gauge the original dimensions of the valley, but historical photos of the valley show its former glory. About 100 meters of water cover the valley floor currently. Taber’s historical photo from 1908 shows meadows (some perhaps actively grazed), wetlands, and a meandering Tuolumne River on the valley floor. Another photo taken a few years later farther up stream depicts the beautiful canyon and its forested and rocky slopes.

The Hetch Hetchy Valley in 1908 before dam construction. Wapama Falls can be seen at
center right in. Photo by Isaiah Taber, published in the Sierra Club Bulletin. Source.

Historical photo of the Grand Canyon of the Tuolumne River by F. Matthes of the USGS
in about 1914. The photo faces west towards the valley with Kolana Rock at center. Source.

Crossing over the dam to the north side of the reservoir, none of the information placards I viewed that are placed to inform the public show any such historical photos of what Hetch Hetchy looked like before its burial, something I note with some cynicism. With its swelling population and capricious annual precipitation, a reliable water supply is critical for California. However, there are alternatives to a dam at Hetch Hetchy, but like so many issues in conservation, the choice comes down to priorities and values. At a minimum we can strive to ensure that another decision like Hetch Hetchy is never made again in our most cherished national landscapes.

References

Wenk E. 2015. Wildflowers of the High Sierra and John Muir Trail. Wilderness Press, Birmingham, AL.

Worster D. 2008. A Passion for Nature. The Life of John Muir. Oxford University Press, New York, NY.

The O'Shaughnessy Dam as seen from the southwest
on the drive towards Hetch Hetchy Valley.

Yosemite V: To Nevada Falls

I’m not a fan of crowded trails, but the trail from Yosemite Valley up through Vernal and Nevada Falls is one of my favorite destinations in Yosemite National Park despite the swell of people it attracts.

Thankfully we started the hike early enough to avoid the swell. From the southeast corner of Yosemite Valley, the trail begins with a modest ascent towards the south and then to the east to gain a view of the Illilouette Valley. A footbridge across the Merced River offers the first glimpse of Vernal Falls in the distance to the east. A short while later one arrives at the southern side of the falls where there is a steep incline up the granite bedrock up to the top of the falls. In wetter seasons, Vernal Falls is a wide white ribbon that cascades over a sharp lip of granite, but at the tail end of a long dry season, the November falls were broken into three independent streams of water flowing down the rock.

Despite the diminished flow, Vernal Falls still seemed to have more water than some of the other waterfalls in the Valley, notably Yosemite Falls which was barely a humble trickle of water. I rather prefer to see Vernal Falls at this lower level of flow; the waterfall produced trickles and ribbons of water rather than a huge thunderous gush. The effect at the base of the falls is very different too since a full cascade of water produces so much spray that the trail becomes doused in mist.

Vernal Falls.

Nevada Falls.

At the top of Vernal Falls, the trail levels out to commanding views of the Illilouette Valley to the west, and the greeting of Emerald Pool, a temporary tranquil rest stop for Sierra snow melt before it plunges over the Vernal. The trail continues east and then crosses over the Merced River again back to its northern bank. Then the trail ascends steeply again in anticipation of reaching the top of Nevada Falls.   

Nevada Falls exceeds Vernal Falls in height, but the latter is more elegant in my opinion since it the sheer 90 degree drop at the crest of the falls results in an elegant plunge of water. At the head of Nevada Falls, the water seems to shoot out more forcefully where it then drops nearly vertically for some distance and finally hits a more sloping granite face where it slides further in sheets down the rocks. Anywhere else, a waterfall such as Nevada Falls would be the chief highlight of the area, but in Yosemite where there are an abundance of natural waterworks, one can be more choosy.

I hiked just a bit beyond Nevada Falls along the John Muir Trail where it heads into the Little Yosemite Valley and crosses into the Yosemite wilderness. Venturing a little off trail, I went just a ways up the eastern slope of Liberty Cap where there was an excellent view of the valley to the east. A pair of granite domes were visible some miles in the distance to the east. The domes appeared to be composed of sheets of granite, like Half Dome itself.  Where the sheets were partly broken, the laminar fractures produced dark shadows on the rocks. These patterns are one of my favorite manifestations of the diversity of granitic composition in the Sierra.

Panorama (looking east) of Little Yosemite Valley from the eastern slope of Liberty Cap.

The trail continues several miles to the summit of Half Dome and the broader Yosemite wilderness for overnight backpacking. Permits are required for both, and while both adventures sound very appealing, I’d prefer to find a time to when the crush of the crowds can be avoided. 

Sheets of water at the base of Nevada Falls.

Monterey's marine gardens

Rocky intertidal at Pt Pinos, with pelicans cruising in
 from the east.

The Monterey Peninsula juts out into the Pacific Ocean at the south end of Monterey Bay along the central California coast. The area is well known for posh homes, golf courses, and tourism, but has an equally wealthy abundance of marine life and history of human connection to the sea. The peninsula is well populated and busy with visitors, hardly wilderness on the terrestrial side, but the rocky intertidal and near-shore subtidal very quickly attenuates human presence and is the realm of rich marine diversity.

Point Piños is situated on the northwest tip of the peninsula and has been a tidepooling destination of mine for years. The intertidal shoreline here consists of smooth bedrock and boulders with only relatively small beaches of coarse sand linking the rocks to the low-elevation upland. Most of the rest of the peninsula is in fact rocky as well, miles of coastline that would take many years of low tides to thoroughly explore.

Yesterday afternoon’s tide was not particularly low, but sufficiently amenable to exploration because the water was calmer than I had expected given the weekend rain that has moved though the northern half of California. There was a light to moderate breeze and partial cloud cover. As the tide dropped, mounds of bright green surf grass (Phyllospadix) that covered low intertidal rocks became exposed. At slightly higher elevations, red seaweeds (many appearing more black then red) dominated the intertidal space. A bit higher still there were carpets of the rockweed Silvetia compressa.

Selected seaweeds at Point Pinos. Upper left: Codium setchellii; upper right: Bryopsis sp.; lower left: Silvetia compressa; lower right: Sarcodiotheca gaudichaudii.

Kelps were not particularly abundant, but I noted three species in the section of coastline that I explored. The feather boa (Egregia menziesii), nearly ubiquitous at all rocky intertidal sites along the Pacific coast, was the most abundant species. A more interesting species to me, Dictyoneurum californicum, was present in a few patches very low in the intertidal. This species grows as a mass of skinny brown blades that sway in unison as the surge flushes in and out of the low intertidal. The other kelp species was the perennial Laminaria setchellii, also quite frequent along the west coast of the US, though this species was not particularly abundant at Pt. Piños and seemed a little tattered by this time of year. 

Brown pelican in flight.

As the sun drifted lower on the horizon, an abundance of bird life filled the skies. Flocks of birds, some in more organized patterns like the lines of brown pelicans, cruised from east to west. In fact, all of these marine birds may have been there all along, but I was more oblivious to their presence as I focused on taking notes of seaweeds at the site.

The peninsula is well protected legally from resource exploitation and is also a conservation-minded community. Much of the rocky coastline and near shore areas of the peninsula are protected in state marine reserves or state marine conservation areas that completely limit take of all species (marine reserves) or allow limited fishing (conservation areas). Pt Piños itself is in the Pacific Grove Marine Gardens State Marine Conservation Area. Monterey is also at the center of the Monterey Bay National Marine Sanctuary, a large NOAA-administered marine protected area that extends along the outer coast from the Bay Area to Cambria south of Big Sur. Sanctuary status protects the nearshore region from oil drilling and mining.

Autumn along the eastern Olympic Peninsula

I’m presently in Washington for a research trip, but the weekend provides some non-work time to explore the magical Pacific Northwest. I drove up to Whidbey Island from southern Washington, but decided to travel along the eastern edge of the Olympic Peninsula instead of the usual route through Seattle. This afforded the chance for more scenic stops and a ride on the ferry, which I love.

Maples and conifer forest along Hood Canal.

Some jagged peaks in the Olympic range from the
Mt. Walker lookout point in the Olympic National
Forest.

The last few days have been sunny and relatively warm in the northwest, a pleasant and unpredictable occurrence this time of year. Autumn colors are in full glory, with bright yellow leaves of big leaf maples particularly abundant. Perhaps because the sun is lower on the horizon as the days shorten at these higher latitudes, colors seem rich and lighting is particularly attractive. The rain and clouds will return to dominate the winter and spring, but I’m fortunate to be up here during a brief window of pleasant weather.

Coastal marshes at the mouth of the Duckabush River
that empties into Hood Canal.

Mt. Rainier in the distance from the Olympic Peninsula.

Reflections of moonlight on water near Port Townsend.

Olympic National Forest.

Marin kayaking

There are few coastal areas along the west coast as urbanized as San Francisco Bay. But tied as our species is to land, the water of the Bay becomes the best place to experience open space. Sitting at essentially the water’s surface in a kayak, the Bay Area becomes more expansive and intimate at the same time. Water, salt and breeze are immediately present. The water is of course always in motion, so the kayaker cannot drift away in thought for too long. Constant awareness of ones’ surroundings is key.

I found a launch spot at a Marin County park on the Tiburon Peninsula and then proceeded to paddle south. The land along this part of the Bay is rocky and abrupt, leaving little easy room for development, so there is some semblance of naturalness on the peninsula. The elaborate coastal homes, some obscene in their size, are tacked onto hillsides or fill the small upland head of tiny beaches. San Francisco State’s marine science facility, converted from an old Navy installation, is located here too.

Looking across Raccoon Strait to the Golden Gate Bridge. Angel Island is to the
left and the Tiburon Peninsula is to the right.

The water enables views unattainable from land, especially along stretches of private land. With calm waters, I was able to row close to shore and observe the seaweeds on the inundated rocks, the lichens painted above the high tide line, and the trees that hang over the water.

A cruising pelican.

Pelicans passed by, some cruising at high speed just above the water surface. Still sporting a sort of dinosaurian vibe from their ancient ancestors, they are my favorite oceanic birds. I observed a dive or two during my time on the water. A diving bird descends rapidly from the sky and then hits the water in a sort of awkward splash. Some of these dives presumably end with a successful catch of fish. Every 20 minutes or so a harbor seal pokes up from under the water to peer at the visitors to his watery world, curious for a time before he dives back underwater. They probably don’t appreciate the boat traffic that criss-crosses the bay, but the smaller and quieter kayaks may be less intimidating to these animals.

North shore of Angel Island.

The Bay was reasonably calm and the main nuisance for a (non-oceanic) kayak was the motor boats that speed by quickly enough to leave wakes. Leaving the Marin mainland, I crossed Raccoon Strait (about 500 paddle strokes required) to arrive at the northern side of Angel Island. The entirety of the island is a state park. A tall island relative to its size, it has steep coastline like the Tiburon Peninsula to the north.

The island was vegetated with trees, shrubs and grasses. I found a narrow beach on the north shore, apparently inaccessible by foot, which would probably make a perfect secret picnic spot for someone arriving by small boat. I did not land on the island, but a visit ashore seems worth another trip to the island. Apparently one can camp at Angel Island too, probably an interesting camping experience in a less crowded oasis just miles away from millions of urban dwellers in all directions.

Curious harbor seal with the Richmond Bridge in the background.

Naturgemalde

Portrait of Alexander Humboldt by Mathew
Brady. Image source.

Alexander von Humboldt was one of the most pioneering naturalists to have lived since the reformation. Celebrated by his colleagues and contemporaries across the world, he was widely esteemed by other well-known global figures including Charles Darwin, President Thomas Jefferson, and the poet Goethe. His is honored in the naming of counties, a major oceanic current, and other geographic features worldwide, but in the United States he is less well known than his fame and accomplishments deserve.

Humboldt’s life was largely unknown to me too until reading Andrea Wulf’s recent biography of Humboldt, The Invention of Nature, published in 2015. Wulf walked in the footsteps of this remarkable man, following the intellectual journey of Humboldt and the other naturalists and thinkers he influenced over the last two centuries. Humboldt was a true “renaissance” individual, a student of an astounding diversity of intellectual disciplines including geology, botany, mining, anthropology, mountaineering, and poetry. Because of his prominence in the development of the fields of natural history and ecology, his life’s story alone would be compelling enough for me, but my appreciation for him deepened when Wolf’s biography enlightened me to his forward-looking social views (including a life-long contempt for colonialism, and slavery). That connection to Humboldt felt even more personal when surmising from his decades of particularly close friendships with men and his lack of marriage that he was probably gay as well¹. As a citizen of science, Humboldt was intensely restless and unendingly curious, traits that I share too, though surely in much less abundance and with much less profit than Humboldt.

Born and raised in Prussia in the late 1700s in relative wealth and comfort, Alexander and his older brother were eased into the intellectual life. At a young age both brothers began to associate with local intellectual figures including Goethe. Humboldt’s formal education and training included university studies and eventually turned to mining as a specialization. Soon he embarked on his first major scientific employment as a mining inspector, traveling throughout northern Europe. He worked hard at his new career, and used his spare time in the evenings to conduct experiments. Nevertheless his true love was exploration and natural history, topics that fueled grand ambitions to travel widely. Departure from Europe to realize his dream wasn’t possible immediately however, because he felt an obligation to family expectations and because Europe was embroiled in an unfavorable political environment at the time.

Two of Humboldt’s scientific publications: Essay on the Geography of Plants (left) and a later edition of Views of Nature (right). Images from the Biodiversity Heritage Library.

After several years waiting to leave what felt like the stifling confines of Europe, a unique opportunity finally befell the young adventurer. Humboldt was given extraordinary freedom by the King of Spain to travel to and explore the vast Spanish territories of Central and South America. With a young French botanist Aimé Bonpland, he sailed from Spain in 1799 to cross the Atlantic. Humboldt was 30 years old at the time, beginning a five year journey that would transform both the individual and the field of natural history itself.

Humboldt and Bonpland’s famous South American expedition brought them through thick tropical jungles, to hot savannas, and to the towering icy volcanic peaks of the Andes. Along the way, the two mapped the landscape and explored. In one excursion, they confirmed the existence of a river rumored to connect the great tropical rivers of the South American rain forest, the Orinoco and Amazon. Heading further south, the team climbed many of the Andean peaks – active volcanoes included – and made almost a full ascent of Mt. Chimborazo, an imposing Andean peak which was then believed to be the tallest mountain in the world.

After extensive travels in the northwestern region of South America, the two explorers also spent time in Mexico, Cuba, and the United States. Along their remarkable journey, Humboldt and Bonpland collected thousands of plant and animal specimens and made meticulous meteorological observations with instruments they brought over from Europe. Humboldt studied ancient indigenous cultures, observed agricultural practices, discovered that the magnetic equator was some six degrees south of the geographic equator, met famous and ordinary people alike, and grew to know more about South America than any other Europeans alive at the time.

Humboldt and Bonpland’s diagram of the distribution of plants with elevation at Mt. Chimborazo in the Andes which appeared in Essay on the Geography of Plants. This detailed figure – which includes data on altitude, climate data, and even the heights to which previous mountaineers had ascended – may be ecology’s first infographic. Image source.

Humboldt returned to Europe and began to publish extensively on his travels, beginning an extensive writing career that would eventually cover a remarkably broad array of scientific topics. The South American journey would turn out to be the most significant expedition that Humboldt took in his life. His desire to travel didn’t wane after returning to Europe from South America, and though he would be denied his deep desire to journey to India, he traveled widely within Europe over the next few decades of life. During this period of his middle age, he lived most of the time in Paris, Berlin, and London, supported in part by a royal stipend granted to him by the King of Prussia that funded his living expenses and publications. Humboldt notoriously failed to manage his finances well, concerning himself much more with science, travel, and publications. He lectured, wrote and received thousands of letters, met and conversed with the leading European scientists of the day, and was generous in supporting young scientists. He was an incessant talker and brash on occasion.

Detailed sections of Humboldt and Bonpland’s figure on the distribution of plants with altitude. The image includes hundreds of species and genus names including the Ericaceous shrub Vaccinium and grass Andropogon (at left), and, to my delight as an enthusiast of algae, the aquatic green algal genus Ulva (at right). Images from publications in Biodiversity Heritage Library.

The fruits of his travels in the Americas were bountiful, enabling many publications and advancing Humboldt to the highest intellectual circles in Europe. But he still wanted to see more. With India inaccessible (it was controlled by the Britian’s East India Company which probably didn’t like Humboldt’s outspokenly unfavorable disposition towards colonialism), he settled on a different adventure that would allow him to continue his study of mountains and confirm the patterns he had already observed in South America and Europe. At about age 60, decades after his South American travels, he embarked on a remarkable loop though Russia on a relatively speedy 8 month journey that covered over 10,000 miles. Relative to his South America expedition, he traveled in greater physical comfort, and with a larger crew of fellow scientists. This trip to the Urals, across Siberia, and to the Altai Mountains in central Asia provided confirmatory evidence for many of the scientific ideas he developed earlier. Though fruitful, in terms of length, biota, and intellectual freedom it could not overshadow the South American journey.

Humboldt’s wide ranging interests and tremendous intellectual capacity manifest throughout his life resulted in accomplishments in an astonishing array of fields. For instance, he wrote about the evolution of species, predating Darwin’s “Origin of Species” by decades (Darwin’s great accomplishment, aided by Wallace, was to piece together disparate lines of evidence to posit natural selection as the mechanism of evolution). He mused about a potential ancient connection between Africa and South America, hinting at the idea of the movement of crustal plates across the earth (plate tectonics), a key principle of modern geology that would not be widely accepted scientifically until 150 years later.

He dabbled in an astounding breadth of disciplines and never failed to impress even the most esteemed scientists of his day. One of his greatest talents was the ability to forge connections between disciplines and ideas, a holistic approach to science that was becoming increasingly rare even in his day when the tendency of scientists was to specialize and pursue reductionist approaches to studying the natural world. To Humboldt, everything in nature and human society was interconnected; mere catalogues of facts or collections of specimens inadequately captured that complexity and relationships.

Humboldt made profound advances in natural history, laying a solid foundation for the field of ecology that would more formally develop from natural history a century later. One of his greatest contributions was “naturgemälde”, a German concept that Wulf explains would roughly translate as “painting of nature”. Naturgemälde was Humboldt’s revolutionary way of depicting nature, a view that emphasized connection and unity between all of life and between life and the abiotic world. He saw the world as non-static and evolving, a key idea that underpins our modern understanding of astronomy, geology, evolution, and ecology.

One of the pivotal moments in the development of the holistic perspective of nature came to Humboldt as he scaled Chimborazo in the Andes. As he passed from the hot tropical forests that occurred at lower elevations to the cooler climate at greater heights, he observed how the flora changed with the ascent. From tropical species at the base of the mountain, the flora changed to finally consist of only lichens in the high alpine. As he climbed, he stopped periodically to make measurements of air pressure, temperature, and other variables. He thought of climate gradients throughout the world and what he knew of plant distributions in other geographic areas. Linking all of these facts, he made the connection between plant distributions and climate gradients, not just for Chimborazo but on a global scale. He would confirm his observations about the link between plants and climate in the Andes with observations in the Altai Mountains made during his travels of central Asia decades later.

Humboldt was the father of biogeography, inspiring the travels of other great naturalists including Charles Darwin and John Muir, both of whom traveled extensively prior to their literary accomplishments. Darwin and Muir both read Humboldt, the former marking his books with meticulous notes aboard the Beagle, and each longed to travel to South America in Humboldt’s footsteps.

A figure by William Woodbridge in 1823 dividing the world into climate zones based on temperature using isotherms. Humboldt invented isoclines, the concept of depicting data in two dimensions (e.g., a map) with lines that denote equal values of a parameter. Isoclines are used to show gradients of temperature (isotherms), barometric pressure (isobars), etc. Woodbridge used global temperature data gathered by Humboldt and others in his figure. Image source.

Humboldt made the connection between forests and ecosystem function, and he noted that a single species could affect an array of other species in an ecosystem. This insight came from observing that the palm trees that dominated the hot plains of the Llanos in Venezuela “spread life around it in the desert”. Humboldt was hinting at concepts that would later be termed “foundation species”, or “ecosystem engineer” by modern ecologists, the idea that one species provides the basis for an entire ecosystem (Dayton 1972, Jones et al. 1997).

In Humboldt’s worldview, humankind was also part of the fabric of nature, but often in negative ways. In both South America and in Russia, he saw the impact of poor agricultural practices on local ecosystems. He noted that deforestation raised local temperatures and decreased soil water capacity, making the vital connection between human effects on ecosystem and subsequent changes in climate at the local scale. He even presciently made this connection more generally, suggesting that the pollution humankind was emitting into the atmosphere could affect temperatures globally. The connections between climate, human activity, and ecosystems is of course one of the most profound environmental issues we face today.

Thanks to Wulf’s excellent biography, Humboldt is my newest intellectual hero and I’m eager to read some of his published work and to walk in his intellectual footsteps. He’s an excellent role model for thinking holistically, and of the ambition and creativity that move science forward.

Notes

1. As a social construct, “gay” or “lesbian” identities probably did not exist in the 18^th or 19^th century western world, but as a sexual and romantic orientation, non-heterosexuality has existed for thousands of years among diverse cultures worldwide. 

2. All images in this post are in the public domain.

References

Dayton PK. 1972. Toward an understanding of community resilience and the potential effects of enrichment to the benthos at McMurdo Sound, Antarctica. In: Proceedings of the Colloquium on Conservation Problems in Antarctica.

Jones CG, Lawton JH, Shachak M. 1997 Positive and negative effects of organisms as physical ecosystem engineers. Ecology 78:1946-1957.

Quammen D. 1996. The Song of the Dodo. Scribner, New York.

Wulf A. 2015. The Invention of Nature. Alexander von Humboldt’s New World. Vintage Books, New York.

Carson-Iceberg Wilderness

Folger Peak from the Carson-Iceberg Wilderness.

After a hot California summer (one for which I was admittedly away for a decent portion), fall appears to finally be here. There are cooler temperatures in the Central Valley and day length is noticeably shorter.

Last weekend I ventured to the crest of the Sierra for a short excursion into the Carson-Iceberg Wilderness, one of the more northerly of the string of wilderness areas, national parks, and national monuments that protect much of the Sierra Nevada. The Carson is south of the Mokelumne Wilderness and north of Emigrant Wilderness and Yosemite National Park. It straddles the crest of the mountains that Muir called the “Range of Light”, incorporating part of the Humboldt-Toiyabe National Forest to the east and the Stanislaus National Forest to the west. The name of the wilderness derives from an early California settler (Kit Carson) and a unique rock formation within the wilderness (named Iceberg).

Map of wilderness areas in the Sierra Nevada
range. Map from sierrawild.gov.

I hiked into the wilderness with B from the Tryon Meadow trailhead. The trail was not very distinct in places, and therefore probably not frequently used, but obvious enough to not get steered too far off course. It passed through lightly dense forests of pine and firs, crossing a few very tiny streams. Some remnant patches of snow lingered on the western flank of Folger Peak, but the evidence of the very wet 2016-2017 California winter was otherwise gone.

We ended the hike at Milk Ranch Meadow, a lovely expanse of sedge-dominated wetlands occupying a broad valley. The lush yellow-green Carex swayed with the mild gusts of wind. The air was cool, but there was a clear sky full of warming sun. Open water in the form of a small lake and even smaller ponds occurred within the Carex meadow, and the wetland itself had standing water.

I spent about an hour trying to photograph dragonflies busy with activity over the wetland. I walked out on to the white skeleton branches of a fallen tree that penetrated into the wetland like a decaying pier. There appeared to be three dragonfly species: a rarer black form, a smaller red species, and a larger blue species that occupied much of my time. The red species was relatively easy to photograph because it would land patiently on the tree branches. The blue species, however, was constantly in motion, hovering above the sedges for a second and then descending into the vegetation, then pairing with a friend (or competitor) to dash off to a new spot above the meadow. They moved nearly constantly, seldom landed, and often mid-flight took a sharp turn to move in a different direction, all aspects of behavior that made them a keen challenge to capture by camera.

The blue dragonfly species.

Wetland at Milk Ranch Meadow.

The wilderness and adjacent national forest had a variety of flowers in bloom, including a very abundant species of pink Sidalcea, blue lupines with large palmate leaves, Spiraea splendens, and yellow and blue asters. Ipomopsis aggregata showed off its flame red flowers, with a long floral tube and five sharp pointed petals.

The high Sierra had some signs of the approaching fall season like a few hints of yellowing branches on the otherwise green aspens. The abundant corn lilies (Veratrum californicum) with their poisonous leaves, growing in patches in open areas, were well on their way to senescence too. Snow apparently returned to the Sierra over the past few days, and while the initial dusting may melt, soon the high peaks will be blanketed again. In the fluctuating annual precipitation regimes of California, and the longer-term pressure of a changing climate, will this year being a return of drought conditions, another wet year, or something closer to the long-term average?

References

Wenk E. 2015. Wildflowers of the High Sierra and John Muir Trail. Wilderness Press, Birmingham, AL.

Wilson L, Wilson J, Nicholas J. 1987. Wildflowers of Yosemite. Sunrise Productions, Yosemite, CA.

The red dragonfly species.

Ipomopsis aggregata (Polemoniaceae) at left and Sidalcea sp. (Malvaceae) at right.