Ecology in history

DEFINITION: Development of the interdisciplinary scientific study of the interactions among organisms and their environments

Ecology, the science that studies the relationships among organisms and their biotic and abiotic environments, emerged as a discipline in the late nineteenth century. It gained prominence in the latter half of the twentieth century as general interest in and awareness of environmental issues increased.

The study of ecological topics arose in ancient Greece, but these studies were part of a catchall science called natural history. The earliest attempt to organize an ecological science separate from natural history was made by Carolus Linnaeus in his essay Oeconomia Naturae (1749; The Economy of Nature, 1749), which focused on the balance of nature and the environments in which various natural communities exist. Although the essay was well known, the eighteenth century was dominated by biological exploration of the world, and Linnaeus’s science did not develop.

Early Ecological Studies

The study of fossils led some naturalists to conclude that many species known only as fossils must have become extinct. However, Jean-Baptiste Lamarck argued in his Philosophie zoologique (1809; Zoological Philosophy, 1914) that fossils represent the early stages of species that evolved into different, still-living species. In order to refute this claim, geologist Charles Lyell mastered the science of biogeography and used it to argue that species do become extinct and that competition from other species seems to be the main cause. In his book On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for Life (1859) English naturalist Charles Darwin blends his own research with the influence of Linnaeus and Lyell in order to argue that some species do become extinct, but existing species have evolved from earlier ones. Lamarck had underrated and Lyell had overrated the importance of competition in nature.

Although Darwin’s book was an important step toward ecological science, Darwin and his colleagues mainly studied evolution rather than ecology. However, German evolutionist Ernst Haeckel realized the need for an ecological science and coined the name oecologie in 1866. It would be another three decades before steps were actually taken to organize this science. Virtually all the early ecologists were specialists in the study of particular groups of organisms, and it was not until the late 1930s that some efforts were made to write textbooks covering all aspects of ecology. Since the 1890s, most individual ecologists have viewed themselves as plant ecologists, animal ecologists, marine biologists, or limnologists.

Nevertheless, general ecological societies were established. The first was the British Ecological Society, which was founded in 1913 and began publishing the Journal of Ecology in the same year. Two years later, ecologists in the United States and Canada founded the Ecological Society of America, which launched the journal Ecology in 1920. The British Ecological Society and the Ecological Society of America have been the leading organizations in ever since, though other national and regional societies have also been established. More specialized societies and journals also began appearing; for example, the Limnological Society of America was established in 1936 and expanded in 1948 into the American Society of Limnology and Oceanography. It publishes the journal Limnology and Oceanography.

Although Great Britain and Western Europe were active in establishing ecological sciences, it was difficult for their trained ecologists to obtain full-time employment that utilized their expertise. European universities were mostly venerable institutions with fixed budgets; they already had as many faculty positions as they could afford, and these were all allocated to the older arts and sciences. Governments employed few, if any, ecologists. The situation was more favorable in the United States, Canada, and Australia, where universities were still growing. In the United States, the universities that became important for ecological research and the training of new ecologists were mostly in the Midwest. The reason was that most of the country’s eastern universities were similar to European ones in being well established with scientists in traditional fields.

Ecology After 1950

Ecological research in the United States was not well funded until after World War II. With the advent of the Cold War, science was suddenly considered important for national welfare. In 1950, the US Congress established the National Science Foundation, and ecologists were able to make the case for their research along with the other sciences. The Atomic Energy Commission had already begun to fund ecological research efforts by 1947, and under its patronage the Oak Ridge National Laboratory and the University of Georgia gradually became important centers for ecology research. (In 1966, five years after its formation, the Institute of Radiation Ecology at the University of Georgia would become simply the Institute of Ecology. In 2007, it would be renamed the Odum School of Ecology in memory of the University of Georgia professor widely regarded as the father of modern ecology.)

Another important source of research funds was the International Biological Program (IBP), which, though international in scope, depended on national research funds. Officially established in 1964, it began operations in 1967 after an extended planning phase. Even though no new funding sources were created after the IBP ended in 1974, its existence meant that more research money flowed to ecologists than in previous years.

Ecologists learned to think big. Computers became available for ecological research shortly before the IBP got under way, and so computers and the IBP became linked in ecologists’ imaginations. The first Earth Day in 1970 helped awaken Americans to the environmental crisis, and they expected ecologists to advise on environmental policy. The IBP encouraged a variety of studies, but in the United States, studies of biomes (large-scale environments) and ecosystems were most prominent. The IBP-funded studies were grouped under the headings of desert, eastern deciduous forest, western coniferous forest, grassland, and (a proposed tropical forest program was never funded). Even after the IBP ended, a number of the biome studies continued at reduced levels.

Ecosystem studies were also large in scale, at least in comparison with many previous ecological studies, though smaller in scope than biome studies. The goal of studies was to gain a total understanding of how individual ecosystems—such as a lake, a river valley, or a forest—work. IBP funds enabled research students to collect data and to use computers to process the data. However, ecologists could not agree on what data to collect, how to compute outcomes, and how to interpret the results. Therefore, thinking big did not always produce impressive results.

Plant and Animal Ecologies

Because ecology is enormous in scope, the discipline was bound to experience growing pains. It arose at the same time as the science of genetics, but because genetics is a cohesive science, it reached maturity much sooner than ecology. Ecology can be subdivided in a wide variety of ways, and any collection of ecology textbooks shows how diversely it is organized by different ecologists. Nevertheless, self-identified professional subgroups tend to produce their own coherent findings.

Plant ecology progressed more rapidly than other subgroups and has retained its prominence. In the early nineteenth century, German naturalist Alexander von Humboldt’s many publications on plant geography in relation to climate and topography were a powerful stimulus to other botanists. By the early twentieth century, however, the idea of plant communities was the main focus for plant ecologists. Henry C. Cowles began his studies at the University of Chicago in geology but switched to botany and studied plant communities on the Indiana dunes of Lake Michigan. He received his doctorate in 1898 and stayed at that university as a plant ecologist. He trained others in the study of succession.

Frederic E. Clements received his doctorate in botany in the same year from the University of Nebraska. He carried the concept of plant community succession to an extreme by taking literally the analogy between the growth and maturation of an and that of a plant community. His numerous studies were funded by the Carnegie Institute in Washington, DC, and even ecologists who disagreed with his theoretical extremes found his data useful. Henry A. Gleason was skeptical; his studies indicated that plant species that have similar environmental needs compete with each other and do not form cohesive communities. Although Gleason first expressed his views in 1917, Clements and his disciples held the day until 1947, when Gleason’s individualistic concept received the support of three leading ecologists. Debates over plant succession and the reality of communities helped increase the sophistication of plant ecologists and prepared them for later studies on biomes, ecosystems, and the degradation of vegetation by pollution, logging, and agriculture.

Animal ecology emerged from zoology. A good illustration of the transition is the career of Stephen A. Forbes, professor of zoology and entomology at the University of Illinois and head of the State Laboratory of Natural History. His responsibilities focused his attention on the practical uses of zoology for agriculture and for fish and wildlife management; he also had a theoretical interest in both evolution and ecology. He brought together these various interests in his 1887 essay “The Lake as a Microcosm.”

One important aspect of the early history of animal ecology was the attempt to understand and describe the growth or decline of animal populations mathematically. Mathematics is a universal language, and the fluctuation of animal populations is a universal problem. Therefore, this aspect of ecology developed globally rather than regionally. It was also possible to use the same mathematical methods to study changes from the standpoints of ecology, evolution, and genetics. This situation promoted a lively exchange and rapid progress in the development of population ecology in the United States, Great Britain, Australia, Italy, and the Soviet Union. The great challenge was to develop equations that could help predict the pattern of population fluctuations. It turned out to be easier to develop mathematical models than to understand or predict the fluctuations of real populations. Nevertheless, these efforts eventually paid off in the ability of fish and wildlife biologists to gauge the level of harvesting that could maintain stable populations versus the level that would cause a population to decline.

Limnology and Marine Ecology

Limnology, the scientific study of bodies of fresh water, is important for managing freshwater fisheries and water quality. The Swiss zoologist François A. Forel coined the term and also published the first textbook on the subject in 1901. He taught zoology at the Académie de Lausanne and devoted his life’s research to understanding Lake Geneva’s characteristics and its plants and animals. In the United States in the early twentieth century, the University of Wisconsin became the leading center for limnological research and the training of limnologists. There, zoologist Edward Birge and fellow faculty member Chancey Juday pioneered North American with their extensive field studies. The university, which has retained its preeminence in the field, established its Center for Limnology in 1982.

Marine ecology is viewed as a branch of either ecology or oceanography. Early studies were made either from shore or close to shore because of the great expense of committing oceangoing vessels to research. The first important research institute was the Statione Zoologica at Naples, Italy, founded in 1874. Its successes soon inspired the founding of others in Europe, the United States, and other countries. Karl Möbius, a German zoologist who studied oyster beds, was an important pioneer of the community concept in ecology. Great Britain dominated the seas during the nineteenth century and made the first substantial commitment to deep-sea research by equipping the HMS Challenger as an oceangoing laboratory that sailed the world’s seas from 1872 to 1876. Its scientists collected so many specimens and such quantities of data that they called upon marine scientists in other countries to help them write the fifty large volumes of reports (1885-1895). The development of new technologies and the funding of new institutions and ships in the nineteenth century enabled marine ecologists to monitor the world’s marine fisheries and other resources and provide advice on harvesting marine species.

The twentieth century brought advances in deep-sea exploration technology that allowed marine ecologists to gain a much more profound understanding of marine ecosystems. Pioneering work in oceanic acoustic research during World War I was followed by the development of acoustic sounding devices and other deep-marine electronic oceanographic instruments. Naturalist William Beebe and engineer Otis Barton ushered in the era of manned deep-sea exploration in the 1930s with their bathysphere dives. The next decade saw the advent of deep-ocean camera systems. Further advances included the first successful missions of untethered research submersibles in the 1950s and the unmanned remotely operated oceanographic systems that emerged in the 1960s. A landmark discovery came in 1977 when a manned submersible expedition explored the distinctive hydrothermal vent ecosystems along the mid-ocean ridge on the ocean floor near the Galápagos Islands.

Space-Based Ecological Observation

Since the late twentieth century, satellite-based capabilities have provided researchers with invaluable tools for assessing and monitoring ecosystems while enabling them to increase their understanding of the earth as a collection of integrated systems. Remote-sensing instrumentation aboard orbital platforms provides scientists with both localized details and an overall global view of terrestrial and marine ecosystems. Regular, repeated collection of data from a particular area affords a means for monitoring how that area is changing over time. Because the data are collected in digital form, they are comparatively easy to integrate with other data. Satellite coverage includes remote areas that would be difficult or impossible to monitor by other means.

Since the United States launched the first satellite in the Landsat series in 1972, a host of environmental satellites equipped with a variety of remote-sensing instruments have been deployed by a number of nations. Notable among these is the Earth Observing System (EOS) series of satellites. A project of the US National Aeronautics and Space Administration (NASA), EOS comprises several orbital missions to gather data on various factors influencing the earth’s climate system and their interactions. The first EOS satellite, Terra (originally called EOS AM-1), was launched in 1999.

Optical instruments that detect different wavelengths within the ultraviolet, visible, and infrared spectral regions, along with radars, light detection and ranging instruments (lidars), and more, provide researchers with insights into a wide range of earth systems. Remote sensing via satellite can be used to monitor and study surface temperatures, snowfield conditions, soil moisture, the contours of the surfaces and floors of the oceans, ocean temperatures, air chemistry, air quality, water quality, and matter in bodies of water, thermal pollution, weather patterns, urban influences on local climate, global climate change, alterations in land cover and land use, human activity and infrastructure, terrestrial and marine animal population size and distribution, loss, plant health and response to stressors, crop yields, deforestation, coral reef conditions, algal blooms, droughts, floods, fires, major oil spills, disease outbreaks and infestations, and encroachment of invasive species.

In combination with ground-based ecological studies, satellite-based research facilitates investigations exploring how individual ecosystems contribute to larger ecologies and how pervasive factors such as an increase in global temperature would affect those individual ecosystems. At a time when scientists are striving to understand the global impacts of human activity, the ability to view ecosystems and their functions within a worldwide context is critical.

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