The Desert Laboratory: Carnegie Science's Pioneering Role in American Ecology

In 1903, Carnegie Science established the Desert Botanical Laboratory in Tucson, Arizona—a boundary-pushing interdisciplinary facility that was the precursor to the Department of Plant Biology, now part of the Biosphere Sciences and Engineering Division. The first desert research center of its kind in the world, the Desert Laboratory was devoted to the study of desert plants and how they tolerate, adapt to, and interact with their environment.

Over its 37 years of active research, more than 60 investigators would conduct research at the lab, producing over 350 papers and books across multiple disciplines. Perhaps the Desert Lab's most significant contribution was to the nascent field of American ecology. Pioneering Carnegie Science researchers played a pivotal role in establishing this discipline, which found creative expression and realization at the Desert Lab.

The Desert Laboratory is Born

In January 1903, two young plant scientists, Frederick V. Coville, Chief Botanist of the USDA, and Daniel T. MacDougal, Director of the New York Botanical Garden, arrived in Tucson, a "cattle town" in the heart of the desert. The previous year, Carnegie Science’s Advisory Committee in Botany, headed by Coville (who had conducted desert fieldwork in Death Valley in 1891), recommended that "there should be established at some point in the desert region of the southwestern United States a laboratory for the study of the life history of plants under desert conditions."

Carnegie Science had enlisted Coville and MacDougal to identify the ideal location for the proposed desert laboratory--one that would provide a distinctly desert climate, desert flora as rich and varied as possible, ready accessibility, and habitability. After five weeks traversing the Southwest by train, horseback, and wagon, they concluded that Tucson perfectly met their requirements. 

The location boasted vast natural desert. It was accessible via the transcontinental Southern Pacific railroad (just four days travel by rail from New York) and communication would be available by telephone from the lab to Tucson, and then by telegraph and cable to the rest of the world. Recognizing the potential benefits of hosting such a facility, the Tucson Chamber of Commerce offered substantial incentives: 40 acres of land on Tumamoc Hill two miles west of town, water supply, electrical utilities, and road construction to the laboratory site.

With the site selected, Carnegie Science officially established the Desert Laboratory in December 1903. $8,000 were appropriated for the lab, which would be funded for a five-year probationary period.

Construction soon began on Tumamoc Hill. The L-shaped building was designed for the desert heat, featuring 18-inch-thick walls built from local volcanic rock and a roof of imported slate shingles with large projecting eaves to provide essential shade. The completed facility housed a laboratory, library, darkroom, and storeroom. The surrounding landscape teemed with iconic desert vegetation, including brittlebush, creosote bush, and the magnificent saguaro cactus, which would soon be officially renamed Carnegiea gigantea (from Cereus giganteus) to honor Andrew Carnegie.

By November 1904, the lab was complete. It would soon become a scientific hub, attracting researchers drawn by the unprecedented opportunity to study desert plants in their natural habitat. Some of these researchers would be pioneers in the developing field of ecology. 

The Early Years: Pioneering Desert Research

Early work at the Desert Laboratory was largely focused on the study of plants' response to environmental variables. Desert Laboratory scientists studied plant physiology under controlled conditions and conducted extensive fieldwork in the surrounding desert, establishing baseline observations of the landscape that would prove invaluable for future ecologists and introducing rigorous quantitative and experimental methods to field studies.

As historian Sharon E. Kingsland explains, "In establishing a research tradition that embraced a wide range of approaches to botany, from physiological experiments to descriptive studies of vegetation and climate, the laboratory's work helped to define the subject matter of ecology. The cumulative effect of this work was to give substance to the new science by creating a solid body of research and inaugurating a tradition of long-term inquiry in various locales. The Desert Laboratory, as a research community, was a nucleus around which the discipline of ecology could form."

William A. Cannon became the Desert Laboratory's first resident investigator in 1903. Previously an assistant at the New York Botanical Garden, the young plant anatomist initially oversaw the completion of the lab's construction before launching his research program. Cannon's charge was comprehensive: to investigate the "morphology, physiology, habit, and general life-history of the species indigenous to the desert." He got to work studying the roots of native desert plants, comparing the root depths of desert plants, and considering the implications for competition among the plant communities. Eventually he expanded his root research to laboratory experiments on the effects of temperature, moisture, and aeration on root development.

In December 1904, the distinguished botany professor Volney M. Spalding, arrived as the lab's first visiting investigator with his wife Effie Southworth Spalding, a scientist in her own right. A plant physiologist with ecological inclinations, Spalding embarked on a detailed ecological survey of Tumamoc Hill and its surroundings to study desert plant distribution patterns. His most enduring contribution was the establishment of nineteen permanent research plots—now recognized as the longest-running ecological research plots in history, continuously studied since 1906.

Expansion and Leadership

Carnegie Science President Robert S. Woodward visited the Desert Laboratory in 1905 and, impressed by the research underway, decided to elevate the facility to departmental status before the completion of its initially planned five-year probationary period. To head the newly established Department of Botanical Research, Woodward recruited MacDougal from the New York Botanical Garden.

MacDougal moved quickly to expand the laboratory's building, grounds, and scientific staff. He retained Cannon and hired several distinguished researchers, including Spalding, Burton E. Livingston, and Francis E. Lloyd as permanent investigators. The maverick British engineer and cowboy Godfrey Sykes joined as laboratory superintendent.

A plant physiologist and leader in laboratory-based evolutionary studies, MacDougal’s research primarily focused on evolution and physiology. Nevertheless, he supported ecological research and advocated for tightening the link between ecology and experimentation. His most significant ecological contribution was a nine-year study (1904-1913) of plant succession at the Salton Sea in southern California. There, flooding created a natural experiment in ecological succession as floodwaters gradually receded and desert plants repopulated the area. Though MacDougal eventually returned to pure laboratory research, his leadership at the Desert Laboratory created an environment where ecological innovation could flourish.

Widely-respected and genial, MacDougal effectively publicized the Desert Laboratory throughout scientific circles. The facility soon attracted substantial attention and hosted a growing number of visiting researchers each summer. These visitors—and initially the lab’s staff and their families—lived in 12x14 foot tents at the base of Tumamoc hill in an informal village community affectionately called "Tumamocville." It was a pleasant place to live and work. As MacDougal wrote, "The perfect good fellowship and fine personal contact of our group of workers…has always made possible the free discussion of a research in all of its stages and aspects." 

Some of the scientists' wives participated actively in research and joined field expeditions, initially traveling by horse and pack mule before the lab acquired its first automobile in December 1909—specially modified to transport scientific equipment.

Among the scientists attracted to the Desert Laboratory were Forrest Shreve and his new wife Edith Bellamy Shreve, who arrived at Tumamoc Hill in 1909. Forrest Shreve would become the scientist most closely identified with the Desert Laboratory, remaining on staff for over three decades while establishing himself as a preeminent desert ecologist and pioneer in the developing discipline.

Forrest Shreve: The Methodical Desert Ecologist

Forrest Shreve joined the Desert Laboratory staff in May 1908, replacing Spalding, who retired due to his declining health. Before coming to the lab, he had received his Ph.D. from Johns Hopkins University, taught at Goucher College, where he met Edith, and conducted research on native vegetation in Maryland and Jamaica.

On Tumamoc Hill, Shreve developed a love and deep knowledge of the desert and dedicated himself to understanding, in his words, "the whole pattern and design of desert life." He embodied the emerging ecological approach, combining strong interests in experimental physiology with meticulous field observations. His research centered on plant distribution patterns and how environmental factors shaped the evolution of plant communities across the desert landscape.

At the Desert Laboratory, Shreve analyzed the changes in the plant populations of Carnegiea and Foothill Palo Verde over time, discovering that the Carnegiea population was declining. His long-term study of the Santa Catalina Mountains, located 20 miles from the lab, employed an array of instruments—atmometers, rain gauges, soil thermographs—to measure environmental variables including precipitation, humidity, evaporation rates, air and soil temperature, and soil moisture content. Through his research, Shreve demonstrated that plant distribution formed a continuous gradient along mountain slopes and that physical environmental factors, rather than interspecies competition, primarily determined the existence, movements, and boundaries of plant communities.

From 1911 to 1920, Shreve served as editor of Plant World, a monthly scientific journal that would become Ecology, the official publication of the Ecological Society of America and the leading American publication for ecological research. The Society's 1915 founding marked a milestone in ecology's development as a self-conscious scientific discipline. Shreve, MacDougal, and Cannon were all charter members. Shreve served as the Society's first secretary-treasurer and later as its president.

Over his career Shreve published 85 papers and books, including several ecological classics. However, a modest and methodical man, Shreve failed to promote and publicize his ideas widely. By the time his landmark study Vegetation of a Desert Mountain Range as Conditioned by Climatic Factors appeared in 1915, another prominent Carnegie Science ecologist was capturing the field's attention: Frederic Clements.

Frederic Clements: The First Philosopher of Ecology

Frederic Clements received his Ph.D. in botany from the University of Nebraska in 1898. After teaching positions at Nebraska and the University of Minnesota, he joined Carnegie Science initially as a temporary research associate in 1913. Following return visits over the next two years, he became a permanent research associate in 1917.

Like Shreve, Clements remained with Carnegie Science until his retirement in 1941. Dubbed the "escaped professor" by his wife, he enjoyed extraordinary institutional freedom. Though he was affiliated with the Department of Botanical Research and spent portions of each year at the Desert Laboratory between 1917 and 1925, Clements also received funding to maintain an Alpine Laboratory he had established on Pikes Peak in Colorado (which became an institutional outpost) and to create a new Coastal Laboratory near Santa Barbara in 1925. This support extended to extensive field expeditions throughout the American Southwest, including conservation work with the Soil Conservation Service during the devastating Dust Bowl of the 1930s.

Often called the "first philosopher of ecology," Clements profoundly shaped the discipline's methodological and conceptual foundations. His most influential publications included Research Methods in Ecology (1905) and his magnum opus Plant Succession (1916)—a 500-page Carnegie publication. His extensive writings provided the emerging field of plant ecology with its essential vocabulary, methodological foundation, and theoretical framework.

Clements revolutionized ecological methodology by championing rigorous quantitative approaches. With Roscoe Pound, he developed the quadrat method—a technique for systematically sampling plant diversity and abundance by counting every plant within representative square plots on a landscape. This innovation marked a profound shift from naturalistic observation to statistical analysis and became a cornerstone of ecology. Research Methods in Ecology advocated for systematic quantitative, statistical, and experimental approaches, and was hailed as a blueprint for the budding discipline.

Serious, single-minded, and ambitious, Clements developed a comprehensive theoretical framework that dominated ecological thought for decades. His central theory conceptualized plant communities as "complex organisms" that developed through predictable stages toward a stable "climax" state. This organismic concept proposed that plant associations functioned as unified entities with developmental trajectories analogous to individual organisms. Clements emphasized competition within plant communities, arguing that succession toward the stable climax state involved the establishment of hierarchical relationships between competing plant forms.

By the 1950s, much of Clements' theoretical framework had been discredited and ecologists modified or abandoned his ideas on progressive succession and climax.

Despite these scientific shortcomings, Clements' legacy remains profound. His advocacy for experimental and quantitative approaches to ecology provided essential vocabulary and unifying statistical techniques for the emerging discipline. His work integrated ecological thought, defined the field's boundaries, framed its interpretive debates, and stimulated further research. His commanding presence and rigorous methodology formed the foundation of early 20th century American ecology.
 

Contrasting Perspectives: Shreve and Clements

A remarkable aspect of Carnegie Science's contribution to early ecology was its simultaneous support of two pioneering ecologists with fundamentally different scientific viewpoints. Both Shreve and Clements believed that environmental factors influence plant distribution patterns and that ecologists should employ precise instruments to study these relationships—but their similarities largely ended there.

Though Shreve never explicitly contradicted Clements' theories of community organization and succession, his research revealed a fundamentally different understanding of desert ecology. Shreve viewed plant communities as gradually changing assemblages and rejected the notions of competition and succession toward climax communities in desert environments. Both scientists found intellectual freedom at Carnegie Science, where they could pursue their divergent approaches while helping to crystallize American ecology as a distinct scientific discipline.

The Closure of the Desert Laboratory

By the 1920s, American ecology had achieved disciplinary coherence, and research activity at the Desert Laboratory had begun to taper. Historian Janice Bowers characterized the period from 1920 to 1927 as the "Carmel Brain Drain," as numerous Desert Laboratory researchers relocated their work to a Coastal Laboratory in Carmel, California, at least seasonally.

In 1928, Carnegie Science reorganized the department as the Division of Plant Biology under the leadership of Herman Spoehr, a chemist and plant physiologist with minimal interest in ecological research. Spoehr had initially arrived at the Desert Laboratory in 1910, before permanently relocating to the Carmel Coastal Laboratory. Under the reorganization, the division headquarters moved to a new plant physiology laboratory at Stanford University. Both Shreve, who managed the Desert Laboratory, and Clements, who oversaw the Alpine Laboratory, now reported to Spoehr.

The Great Depression of the 1930s severely impacted the Desert Laboratory as financial constraints prevented researchers from visiting. In 1929, 14 scientists had worked at the facility for at least 3 months, with an additional 42 making shorter visits. In 1932, visiting scientists had dwindled to just six, and the following year there were no visitors at all. 

The Desert Laboratory was officially closed in 1940. It was one of a number of programs terminated by Carnegie Science's new president Vannevar Bush (others included Clements' Alpine Laboratory, the Marine Laboratory at Dry Tortugas, and the institution's programs in archaeology, paleontology, and paleobotany). To avoid the "sacrifice of valuable elements," the Desert Laboratory facility was turned over to the U.S. Forest Service. Later, custodianship passed to the University of Arizona, which maintains the Desert Laboratory for ongoing research and public education to this day.
 

Legacy and Continuing Impact

The Desert Laboratory's pioneering work established a foundation for ecological research that continues to influence science today. During its 37-year history, the laboratory fostered research that helped transform ecology from a descriptive natural history pursuit into a rigorous scientific discipline with established methodologies and theoretical frameworks.

The permanent plots established by Spalding in 1906 remain the world’s longest continuously monitored ecological sites, providing invaluable data on desert ecosystem dynamics over more than a century. This unprecedented temporal perspective offers critical insights into long-term environmental change processes that would be impossible to observe over shorter timeframes.

As a full-circle moment, Spoehr's Department of Plant Biology would spin off a new Department of Global Ecology in 2002 as part of Carnegie Science's centennial celebrations. Established by Founding Director Chris Field and his longtime colleague Joe Berry, the department, now part of Biosphere Sciences and Engineering Division, advanced a new, Earth System approach to the discipline. 

As modern ecologists, including those in Carnegie’s Biosphere Sciences and Engineering division address urgent global challenges including climate change and destruction of ecosystems, the methodological innovations and ecological insights developed at Tumamoc Hill continue to inform current research approaches. The Desert Laboratory stands as a testament to Carnegie Science's enduring commitment to boundary-pushing scientific exploration.