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The consequences of climate change for ecosystem structure and function remain largely unknown. A 20-year study of a high-elevation riparian system in Arizona shows substantial changes in both structure and function related to climate change. Abundances of dominant deciduous trees have declined dramatically over the 20 years, correlated with a decline in over-winter snowfall. Snowfall can affect over-winter presence of elk, whose browsing can significantly impact deciduous tree abundance. Seven species of birds were found to initiate earlier breeding associated with an increase in spring temperature across years, with minimal consequences for populations. Climate had much larger consequences for these seven bird species by affecting trophic levels below (plants) and above (predators) them. In particular, climate-related declines in deciduous vegetation led to decreased abundance of preferred bird habitat and increased nest predation rates. In addition, summer precipitation declined over time, and drier summers also were further associated with greater nest predation in all species. The net result was local extinction and severe population declines in some previously common bird species; one species increased strongly in abundance, and two species did not show clear population changes. Thus, climate can alter ecosystem structure and function through complex pathways that include direct and indirect effects on abundances and interactions of multiple trophic components.

Declining snowfall over the 20 years of study have allowed elk to remain over winter and increase browsing pressure on the habitat. Here is a typical canyon maple stand showing the browse line and lack of understory vegetation below browse height. Note the dead understory limbs from over-browsing, and the open area in the forefront. Historically, stands such as this would have a thick understory. Many maple and quaking aspen ramets exist throughout this stand, but are browsed down.

Another typical canyon maple stand showing the browse line, lack of understory vegetation, and dead limbs in the understory. Also, note again the open areas in the background, showing that conifer incursion or other plants are not crowding out the deciduous vegetation.

The Red-faced Warbler (Cardellina rubifrons ) uses maple and fir habitats for nesting and feeding, and shows a mild decline in abundance over the 20 years of study, associated with decreased abundance of its habitat.

The Hermit Thrush (Catharus guttatus ), here feeding its normal brood size of four young, is a common species in this system. It nests and feeds in both conifers and maple. It does not have a clear population trend over the 20 years, but shows a clear decline over the last 15 years, associated with the decline in habitat and summer precipitation.

The Orange-crowned Warbler (Vermivora celata ) depends on maple for nesting and feeding. It has shown a major decline in abundance over the 20 years, associated with the decline in maple, but also associated with decreasing summer precipitation and increasing nest predation rates.

In their article, Helmuth et al. describe how latitudinal patterns of intertidal thermal stress may be more complex than anticipated. Using a series of biomimetic temperature loggers designed to mimic the thermal characteristics of mussels (Mytilus californianus), shown here, they measured temperature patterns at sites ranging from northern Washington to southern California.

Fig. 1

Some ecological ideas developed gradually and only gained coherence and details after they had become commonplace. The history of two interrelated ideas, food chains and food webs, is an example of a gradual, cumulative history. Here is a brief survey of these concepts from about 1700 to 1970 (Fig. 1).

The earliest identified food chains seem to have concerned hyper-parasitism (Egerton 2005, 2006a), which students of insects discovered in the later 1600s. But it was entrepreneurial naturalist Richard Bradley (Egerton 2006b) who generalized the concept (Bradley 1718, part 3:60–61):

…Insects which prey upon others are not without some others of lesser Rank to feed upon them likewise, and so to Infinity; for that there are Beings subsisting, which are not commonly visible may be easily demonstrated…in a Microscope.

Fig. 2

This was turned into verse by Jonathan Swift in 1733 (lines 341–344) (Fig. 2). So, Nat’ralists observe, a Flea Hath smaller Fleas that on him prey, And these have smaller yet to bite ‘em, And so proceed ad infinitum. In Bradley’s account, food chains illustrated the balance of nature (Egerton 1973:333–335). Swift was a prominent literary figure who had a general interest in science, but his lines on fleas were meant as a swipe at lesser poets. Neither Bradley nor Swift provided an illustration, so we can help them out with this one from Alfred Elliott’s 1957 Zoology textbook (Fig. 3), though Elliott borrowed the idea for the central figures of fleas from Robert Hegner’s 1938 book, Big Fleas Have Little Fleas, or Who’s Who Among the Protozoa.

Fig. 3

Carl Linnaeus, in an ecologically important essay, “The Economy of Nature” (Linnaeus [Latin] 1749; [English] 1775:114, 1977), briefly itemized the stages of two food chains, one terrestrial, one aquatic (Egerton 2007a). There are likely other naturalists between Linnaeus and Darwin who reported on food chains, but attracted little notice. Darwin may be the first to report a food web, occasioned by the Beagle’s stop over at the rather barren island of St. Paul on 16 February 1832. He gave its location as 0° 58’ north latitude and 29° 15’ west longitude, and 540 miles from America. He found only two species of birds, the booby (a gannet) and the Noddy Tern. The latter built a simple nest with seaweed. Then follows his food web (Darwin 1839:10):

By the side of many of these nests a small flying-fish was placed; which, I suppose, had been brought by the male bird for its partner…quickly a large and active crab (Craspus), which inhabits the crevices of the rock, stole the fish from the side of the nest, as soon as we had disturbed the birds. Not a single plant, not even a lichen, grows on this island; yet it is inhabited by several insects and spiders. The following list completes, I believe, the terrestrial fauna: a species of Feronia and an acarus, which must have come here as parasites on the birds; a small brown moth, belonging to a genus that feeds on feathers; a staphylinus (Quedius) and a woodlouse from beneath the dung; and lastly, numerous spiders, which I suppose prey on these small attendants on, and scavengers of the waterfowl.

After reading this account, Rear-Admiral William Symonds told Darwin that he had seen at St. Paul crabs drag young birds from nests and eat them. Darwin added his information to this passage in the second edition (1845) of his book on the voyage of the Beagle (Edwards 1985:34).

Fig. 4

In The Origin of Species (1859:73–74), Darwin reported the most famous example of a food chain in the scientific literature (Fig. 4).It is in chapter 3 on the “Struggle for existence,” and involves humble bees (called “bumble bees” in America) pollinating red clover; though some bees were eaten by field mice, the mice, in turn, were kept in check by domestic cats. Darwin speculated that if it were not for the cats, the mice would decimate the bees, and the clover would go unpollinated, since only humble bees pollinate clover. A later, unknown commentator extended this chain further (Milne and Milne 1966:6) by suggesting that old maids commonly kept cats, that clover-fed cattle were eaten by British seamen who protected the British Empire, and that if it were not for old maids, the British Empire would fall! In other words, Darwin’s food chain became a biological version of Englishman George Herbert’s well-known admonition (1640):

For want of a nail the shoe is lost,

For want of a shoe the horse is lost,

For want of a horse the rider is lost.

In America, this admonition is attributed to Ben Franklin, who borrowed it without acknowledgement for Poor Richard’s Almanac (1757). But getting back to Darwin’s food chain, in 1947 W. L. McAtee pointed out that Darwin’s food chain dynamic lacks full validity, since we now know that honey bees also pollinate red clover and that humble bees often appropriate mouse holes, so humble bees and mice have an ambiguous relationship. In Darwin’s defense, he heavily depended on H. W. Newman’s 1850–1851 study “On the habits of the Bombinatrices” (Darwin 1975:183).

The next discussion of note for our purposes is from a remarkable German zoologist, Karl Semper. In 1877, he gave 12 lectures at the Lowell Institute in Boston, published simultaneously in English and German editions in 1881. The English title is Animal Life as Affected by the Natural Conditions of Existence. This book was the first detailed synthesis of animal ecology. In a discussion of the food of herbivores and carnivores (Semper 1881:51–52), he pointed out that when herbivores transform vegetation into flesh, there is a loss of mass due to oxidation of organic material, and that the same is true when carnivores transform the flesh of their prey into their own flesh. To illustrate this, he arbitrarily assumed a 10 to 1 ratio of food to flesh. One thousand units of plant food could only support 100 units of a herbivore, and those 100 units of herbivore could only support 10 units of a carnivore. Although his book has 106 illustrations, this generalized food chain was not illustrated. However W. E. Pequegnat’s diagram (Fig. 5) from Scientific American (1958:86) captures Semper’s concept, even to the point of using a 10 to 1 ratio. Semper wrote at a time when there was little quantified thinking in natural history. He had first trained as an engineer and then as a physiologist (Mayr 1975), and that background came to the fore in this discussion. Although his book was widely read, apparently no one carried this line of quantitative thinking any further in the 1880s or 1890s.

Fig. 5

We are used to seeing food chains or webs diagrammed. The advantages are obvious: they provide a visual panorama of detailed information. The early history of such diagrams is elusive. The bibliography on food chains and webs that Allee, Emerson, Park, Park, and Schmidt compiled (1949:514) can assist in the search. However, they did not discover the earliest ones now known, published in 1880 by Lorenzo Camerano, which are reprinted in an English translation of his article (1994:377–378). Since Camerano’s two diagrams do not resemble any known from later zoologists, it seems likely that he did not have much, if any, influence on later diagrams. Joel Cohen (1994:353–355) suggests that Camerano was influenced by diagrams for other purposes in books by Darwin and by Hermann Helmholtz, though Camerano’s diagrams do not resemble theirs. Like Semper’s, Camerano’s food webs are generalized rather than specific.

The earliest specific food web I have found (Fig. 6) is on “The boll weevil complex,” published in 1912 by Pierce, Cushman, and Hood in a USDA Bulletin. Their motive was to promote bowl weevil eradication—by encouraging its predators and parasites. Theirs may not have been the first specific diagram published, because others appeared about the same time in different biological specializations, where it is unlikely that the members of one specialization were reading the literature of other specializations.

Fig. 6

Fig. 7. Victor Shelford at age forty in 1917, associate professor at the University of Illinois. Photo courtesy of V. E. Shelford personal papers.

The following year, University of Illinois animal ecologist Victor E. Shelford (Fig. 7; photo, Croker 1991) published Animal Communities in Temperate America as Illustrated in the Chicago Region, which contained diagrams of both aquatic (Fig. 8) and land food webs (Fig. 9). There is no reason to suspect that he was influenced by the boll weevil diagram of 1912. Shelford used both of his diagrams to show how the community tends toward equilibrium, although the terrestrial community was more complex than the aquatic community, and consequently its equilibrium was more precarious. Shelford became a leading American animal ecologist (Croker 1991); his book was reprinted in 1937 and 1977.

Fig. 8

Fig. 9

The earliest known food web diagram for a marine community was drawn by Danish fishery biologist Johannes Petersen (Fig. 10) in “A preliminary result of the investigations on the valuation of the sea”(1915). He studied the Kattegat region of shallow water between eastern Denmark and Sweden (Fig. 11), an area with maximum length of 150 miles and maximum width of 90 miles. Significantly, he attempted to establish the annual productivity for this region, and his diagram indicates the thousands of tons of each group of organisms, with both a number and a proportioned rectangle (Fig. 12). In the text he stated that the eel-grass (Zostera marina) figure of 24,000,000 tons represents only the amount produced in the summer, and that the annual production is twice that. Presumably, all the other figures are annual production and not just summer production. The tons of plaice and cod are the actual commercial catch of those fish from International Fishery Statistics for 1910, and that was possibly true also for the tons of herring given, though he did not say so. The numbers given for other animals seem to be estimates. Although he indicated on his diagram that herring fed on plankton, he thought plankton was much less important than Zostera as a foundation for this food web. He concluded that the Kattegat had a “very unfavourable proportion between producers and consumers”(Petersen 1915:32). What he meant by this seems to be indicated by the following sentence in which he stated that carp ponds have “even without artificial feeding, given a yield of fish per hectare several times greater than that of the Kattegat.” Petersen reproduced the same diagram with minor alterations in his final report, “The sea bottom and its production of fish-food”(1918:23).

Fig. 10	Fig. 11
Fig. 12

His colleague, H. Blegvad, also used rectangles in his diagram of “Food of fish and principal animals in Nyborg Fjord” (1916:24) (Fig. 13)but without attempting to represent precise quantities. However, he did give quantitative data in the text of his article, which provided some sense of the quantities of organisms involved at each level.

Fig. 13

In the same year as Blegvad, the American zoologist Harold Sellers Colton published what Jonathan A. D. Fisher calls (2005:145) “possibly the first intertidal marine food web ever illustrated.” It is in Colton’s article on a carnivorous snail, Thais lapillus (now Nucella lapillus), and shows both which animals the snail eats and which animals eat the snail (Fig. 14). Colton did not indicate what inspired his diagram, but his brief bibliography does include Shelford’s book (1913). Fisher did not find references in the later relevant literature to Colton’s two articles on this snail (probably due in part to Colton’s leaving marine biology for archeology [Miller 1991]), so we do not know of any influence that his diagram exerted.

Fig. 14

Fig. 15

Charles Elton (Fig. 15) helped make such diagrams commonplace. He went on an Oxford University Arctic expedition in 1921 to Spitsbergen and took along Shelford’s book as a possible model for his own study (Elton 1966:33). However, Elton soon realized that the community he studied had a different dynamic than Shelford’s aquatic and terrestrial ones. Elton was impressed by the transfer of food from sea to land, which is reflected in his diagram (Fig. 16) published in 1923.

Fig 16

Although V. S. Summerhayes is listed as the senior author of their joint study, since he was a botanist, we can assume that Elton developed this diagram, in which plants are not emphasized. Two years later, in 1925, Elton published this much simpler Canadian food web (Fig. 17),which includes information on the lengths of animals. In 1924, English fishery biologist A. C. Hardy published a diagram (Fig. 18)on food consumed by herring at different stages of development. It bears no similarity to any diagrams previously shown, and it seems likely that he either was inspired by some unidentified example from the fisheries literature, or that he independently developed his diagram. Be that as it may, in 1927 Elton published his classic textbook, Animal Ecology, which reprinted and explained these last three diagrams by himself and Hardy. In that book Elton also introduced (1927:55) the terms “food chain” and “food cycle.” Widespread use of his book popularized the use of food web diagrams. In both Hardy’s diagram and in Elton’s for 1925, more information was conveyed than merely which animal ate which food. Hardy’s additional information was on the age of herring in relation to food, and Elton’s was on the size of the consumer in relation to food. Elton also popularized the idea of a food pyramid (1927:68–70), which concept had been implied by Semper.

Fig. 17

Fig. 18

 

In 1926 Germany’s leading limnologist, August Thienemann (Fig. 19) published this unique food web of lakes (Fig. 20). His 50-page article on nutrient cycles in lakes introduced into limnology the terms “producers,” “consumers,” (though Petersen 1915 [quoted above] had used both terms in marine biology) and “reducers.”

Fig. 19

Fig. 20

Thienemann’s 1926 paper and two of his other papers influenced an American postdoctoral student, Raymond Lindeman, who produced one of the most influential diagrams in the history of ecology (Fig. 21), though few if any ecologists have published similar diagrams.

Fig. 21

It appeared in his posthumous paper, “The trophic–dynamic aspect of ecology” (1942). Like Thienemann’s diagram, Lindeman’s is a generalized food web, but both men had hard specific data backing up their concepts. In that respect theirs were similar to diagrams by Shelford, Elton, and Hardy, which illustrated specific food webs, and unlike Semper’s generalized food web, which was an educated guess. In the caption to his diagram Lindeman indicated that it was similar to one he had published the previous year. A comparison of his two diagrams indicates what he learned in his year at Yale University working under Evelyn Hutchinson (Cook 1977). The 1941 diagram is identical to the 1942 diagram except it lacks the symbols for trophic levels along the side. Lindeman (1942:159) used Thienemann’s terms “producers” and “consumers,” but suggested substituting the term “decomposers” for Thienemann’s term, “reducers,” to signify that the indicated process was not just chemical, but also biological.

Fig. 22

Fig. 23

In 1943, a year after Lindeman’s 1942 diagram appeared in the journal Ecology, Harvard marine ecologist George Clarke published this conventional food web (Fig. 22), but three years later, after he had studied Lindeman’s diagram and its explanation, Clarke published his diagram (Fig. 23) in Ecological Monographs, of a marine food web that emphasizes productivity and human removal of material. It also shows Clarke’s concern for the rate of production at each trophic level.

Fig. 24

Fig. 25

The Odum brothers, Eugene and Howard Thomas, carried Lindeman’s thinking further. The Atomic Energy Committee became interested in radiation ecology (Kwa 1989:48), and Eugene Odum (Fig. 24; photo, Craige 2001) developed a program at the University of Georgia to study food chains at the Savannah River Research Facility to trace radioactive pollution (Craige 2001). By injecting plant stems with radioactive phosphorus-32, he and his colleagues traced it up the food chain to leafhoppers, beetles, and spiders (Kwa 1989:58). About 1957 the programs at Oak Ridge and Savannah River converged, with both programs using radioactive tracers to measure the flow of materials up the food chain (Kwa 1989:66). In the second edition of Eugene Odum’s famous textbook, Fundamentals of Ecology (1959:47), there is a 1949 diagram of a food chain (Fig. 25). When I saw it, I assumed that Lindeman’s influence had flowed across the Atlantic in just a few years, but when I compared it with British ecologist Erichsen Jones’ own diagram, I discovered what Odum meant when he wrote that his diagram was “redrawn” from the one by Jones: Odum added the labels to the left of the diagram as a pedagogical aid.

Fig. 26	Fig. 27
Fig. 28

Howard Thomas Odum (Fig. 26; photo from Katherine Ewel) received his graduate training under Hutchinson at Yale. (In 1954 he taught me freshman zoology at Duke.) In 1956, he produced a diagram (Fig. 27) of matter and energy flow, in steady-state flowing-water communities in Florida. At that point, the reader could still understand the diagram without special training. However, H. T. Odum continued developing his thinking along the lines of systems ecology and used symbols from electrical engineering. By 1971 he published esoteric diagrams (Fig. 28) that integrate humans into the biotic community. This was an important step towards founding several applied ecological sciences (Mitsch 1994, Hall 1995, Egerton 2007b).

Other ecologists developed food chain and food web concepts in another direction. In 1948, D. E. Howell reported finding DDT in human fat, and by 1949 biologists were reporting that fish feeding on insects killed by DDT were also being killed (Hoffmann and Surber 1949, Langford 1949).

Fig. 29

Fig. 30

Rachel Carson (Fig. 29) publicized the discovery of insecticides traveling up the food chain in ever-increasing concentrations in her best-selling book, Silent Spring (1962:110–111), as did Robert Rudd in his less-read book, Pesticides and the Living Landscape (1964). Carson did not provide diagrams, and the ones Rudd used were quite simple. Here are four (Fig. 30) of the seven diagrams in his book. DDT was the most notorious insecticide, and in 1967 George Woodwell published a diagram (Fig. 31) in Scientific American showing increased concentrations of DDT as it progressed up the food chain. By 1970, Clive Edwards constructed a much more detailed food web (Fig. 32), showing DDT pathway and concentrations from the time of spraying DDT into the air, all the way up the food chain until it became concentrated in predatory birds, mammals, and humans.

Fig. 31

Fig. 32

From simple narratives around 1700, food chain and food web concepts have been developed into progressively more sophisticated vehicles for conveying ecological ideas (Polis et al. 2004, de Ruiter et al. 2005). Lorenzo Camerano’s two 1880 diagrams of food webs had no known influence, but after the visual stimulus of diagrams became established in the early 1900s, many ecologists found creative ways to express visually their discoveries concerning food chains and webs.

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Camerano, L. 1994. On the equilibrium of living beings by means of reciprocal destruction. Claudia M. Jacobi, translator. J. E. Cohen, editor. Pages 360–380 in S. A. Levin, editor. Frontiers in mathematical biology. Springer-Verlag, Berlin, Germany.

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Acknowledgments

This is a revised version of a talk given at the ESA Annual Meeting in August 2006 in Memphis, Tennessee. For comments preceding the talk, I thank Robert P. McIntosh, Professor Emeritus of Biology, University of Notre Dame (now in Florida). For several references used in the revision, I thank Jonathan A. D. Fisher, Department of Biology, University of Pennsylvania, Philadelphia.

Frank N. Egerton
Department of History
University of Wisconsin-Parkside
Kenosha WI 53141
E-mail: [email protected]

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All of his travel books and the dissertations are listed in B. H. Soulsby’s catalogue of Linnaeus’ works (1933:23–26, 99–151). Florence Caddy (1886–1887) provides two good maps on Linnaeus’ travels, though the caption to the one at the end of volume I is misdated 1735–1738 (read 1732–1738). Wilfrid Blunt (1971) includes maps and summaries of the trips in his biography of Linnaeus. Linnaeus’ travel books show his broad interest in plants, animals, geology (Merriam 2004), and economic uses of natural history (Linnaeus 1766, 1781:1–67, 1977, Koerner 1999, Müller-Wille 2003, Rausing 2003). David Black selected natural history extracts from Linnaeus’ books on the 1732 and 1741 trips, which he published with a map and modern illustrations by Stephen Lee (Linnaeus 1979).

Linnaeus’ first expedition was undertaken in 1732, begun on 12 May, his 25th birthday, and lasted until 10 October. He traveled north to Lapland and then west to the Norwegian coast. On the return journey he traveled in Finland down the eastern side of the Gulf of Bothinia to Åbo and then crossed to Stockholm. It was his longest journey—he estimated 633 Swedish miles or about 3800 English miles (1811, II:270, 1971)—and the subject of his longest travel book. It was also the one travel book that he illustrated. A historian of Swedish botany judged this trip “the most productive exploratory expedition ever undertaken in Sweden”(Fries 1950:18). It was sponsored by the Royal Academy of Sciences at Uppsala, which declined to publish his manuscript, and an English translation was published (1811) long before the Swedish version (1913). Linnaeus’ most recent biographer, who reads Swedish, judges some of his behavior and writings on this trip rather harshly (Koerner 1999:59–65). She says he doubled the actual distance he traveled in his report (her figure is 4500 miles) because he was to be paid per mile, that he drew a map indicating travel to places he had not visited, and that he later claimed to have stayed in Lapland much longer than he had. While I cannot check all her claims, this statement is doubly wrong: “He never passed the sixtieth degree north Latitude, which marks the Arctic Circle” (Koerner 1999:61). The Arctic Circle is actually at 66°30’, and he did cross it. He visited Jokkmokk (29 June) just north of that line, and more than half a dozen other places north of Jokkmokk (see map in Blunt 1971:41). She does not accuse him of inventing any of his natural history observations.

When he visited the cataract of the Elf-Carleby River on 13 May, he described the salmon fishery below the cataract, the foam and spray that the cataract generated, and surrounding plants. But he did not merely describe; he also pondered how species lived (Linnaeus 1811, I:13, 1971):

Oak trees grow on the summits of the surrounding rocks. At first it seems inconceivable how they should obtain nourishment; but the vapours are collected by the hills above, and trickle down in streams to their roots.

Linnaeus’s illustrations did not always represent what he discussed in most detail. For example, he made an excellent drawing of a crane fly but only recorded that he collected it at Umeå on 9 June.

Fig. 2. Crane fly (Pedicia rivosa). Linnaeus 1811, I:186, 1971.

Remarkably, he shot a hawk owl from his horse, “going on at a good rate” (Linnaeus 1811, I:204, 1971), at 12:15 am. Regrettably, it was too damaged by the shot to be stuffed, but at least he drew its picture.

Fig. 3. Hawk Owl (Surnia ulula). Linnaeus 1811, I:205, 1971.

For two insects collected at Lulea on 21 June, he provided both illustrations and discussion (Linnaeus 1811, I:233, 1971)

Fig. 4. Capricorn Beetle (Cerambyx sutor) and black fly (Culex equines). Linnaeus 1811, I: 232, 1971.

Fig. 5. Rhododendron lapponicum. Linnaeus 1811, I:301, 1971.

1. A large Capricorn Beetle, variegated with a lighter hue. (Cerambyn Sutor, the female.) The horns were longer than the body, black, consisting of ten joints, each joint ash-coloured at its base. Body black, rugged, its wing-cases besprinkled here and there with clustered dirty spots. Abdomen cylindrical, covered towards the thorax with beautiful red lice, (Acarus coleoptratorum).

2. A minute black fly, with a roundish body and white wings, (Culex equines). This infested the horses in infinite multitudes, running under the mane, and attacking them with great fierceness, being not easily driven off.

The scientific names of species he discussed or illustrated were added by the editor, James E. Smith, from Linnaeus’s Flora Lapponica (1737) and Fauna Svecica (1746). He also discussed at length a rhododendron he drew on 8 July in the Lapland Alps (Fig. 5), but only to describe it and to evaluate whether it belonged in the azalea genus (Linnaeus 1811, I:299–301, 1971).

On the Norwegian coast at Torfjorden he went fishing in a boat and caught with hook and line “plenty” of Sey-fish (Gadus virens), which he drew (Fig. 6). He found remora sticking to some of these 10-inch fish.

Fig. 6. Sey-fish (Gadus virens). Linnaeus 1811, I:342, 1971.

He also observed, collected, and drew four different kinds of medusa (jellyfish), but made no observations on their behavior or food (Linnaeus 1811, I:336–339, 1971). Two later Linnaean dissertations were on marine subjects: Noctiluca Marina (1752) on minute phosphorescent “insects,” and Natura Pelagi (1757) on fish, turtles, and cetaceans (Smit 1979:120–123).

Reindeer were important draft and milk animals to Laplanders, and Linnaeus discussed them repeatedly in Lachesis Lapponica (1811), but only illustrated bridle, harness, and antlers (Linnaeus 1811, I:103–110, 135, 1971). He illustrated reindeer themselves in the frontispiece of Flora Lapponica, 1737). Their antlers were beginning to sprout in June, initially covered by soft skin which was often bloody from mosquito bites.

Fig. 7. Frontispiece of Linnaeus, Flora Lapponica (1737), showing reindeer. The man seated in the foreground is Linnaeus. The steep mountains in the background do not represent the topography he found in Lapland.

Females have smaller antlers than males. Squirrels gnawed antlers from previous years (Linnaeus 1811, I:127–128, 1971). Linnaeus’ discussion of what reindeer eat is interesting (Linnaeus 1811, I:161–162, 1971):

The reindeer suffers great hardship in autumn, when, the snow being all melted away during summer, a sudden frost freezes the mountain Lichen (L. rangiferinus), which is his only winter food. When this fails, the animal has no other resource, for he never touches hay. His keepers fell the trees in order to supply him with the filamentous Lichens that clothe their branches; but this kind of food does not supply the place of what is natural to him. It is astonishing how he can get at his proper food through the deep snow that covers it, and by which it is protected from the severe frosts.

The reindeer feeds also on frogs, snakes, and even on the Lemming or Mountain Rat (Mus Lemmus), often pursuing the latter to so great a distance as not to find his way back again. This happened in several instances a few years ago, when these rats came down in immense numbers from the mountains.

But he also reported that they ate nothing in hot weather, when mosquitoes were very troublesome (Linnaeus 1811, I:308, 1971). Later, he commented that the Lapps were negligent not to gather Lichen rangiferinus and horsetail (Equisetum fluviatile) in summer for winter fodder (Linnaeus 1811, II:107–108, 1971). Females give birth in May and fawns grow simple antlers their first year (Linnaeus 1811, I:313, 1971). In warm weather reindeer are tormented by the bites of gadflies (Oestrus tarandi), which leave so many scars that one author mistakenly thought they were caused by smallpox. (For more details on this fly and reindeer, see Linnaeus 1739, 1746b; part of the latter is translated by Susan Novikoff in Usinger 1964:5–6.) One insect, “probably a species of Tabanus” (Linnaeus 1811, I:280–281, 1971) bores into reindeer and lays its eggs under the skin, and the young leave by the same hole. The Lapps squeeze out the larva from their pustules to lessen the reindeer’s pain. Another fly (Oestrus nasalis) lays eggs in reindeer nostrils (Linnaeus 1811, II:45, 1971). Reindeer also suffer from an epidemic disease that Laplanders called Pekke Kattiata that could be fatal (Linnaeus 1811, II:39–40, 1971). These observations were also included in a 1754 dissertation, Cervus Rheno, defended for a doctorate degree by Charles F. Hoffberg, and is translated into English (Linnaeus 1781:167–214, 1977).

On 17 July 1732, Linnaeus had a chance to see lemmings, which he described, and said they ate grass and reindeer moss. They lived mainly in the Scandinavian alps, but (Linnaeus 1811, II:19, 1971):

in some years thousands of them come down into the woodland countries, passing right over lakes, bogs, and marshes, by which great numbers perish. They are by no means timid, but look out, from their holes, at passengers, like a dog. They bring forth five or six at a birth. Their burrows are about half a quarter (of an ell?) deep.

(The parenthetic question about burrow depth was inserted by the book’s editor.) Later in the book, Linnaeus raised his estimate of their numbers from thousands to millions and admitted that “nobody knows what becomes of them” (1811, II:82–83). In a still later article (Linnaeus 1740; partly translated in Blunt 1971:60), he rejected the belief that lemmings fall from clouds.

Fig. 8. Linnaeus’ wedding portrait, 1739, by J. H. Scheffel, now at Hammarby, Linnaeus’ summer home, managed by Uppsala University. Color reproduction courtesy of Hunt Institute for Botanical Documentation.

Without publishing his travel journal, Linnaeus still publicized his achievements, and the governor of Dalecarlia province offered to fund a survey of that province. Linnaeus agreed, and seven medical students gained permission to come along at their own expense. They first traveled to Falun, the provincial capital (where Linnaeus met his future wife), and then departed on their expedition on 3 July 3 1734, taking along the governor’s two sons. Linnaeus was an organizing genius, and he delegated specialized tasks to each student: geography; climate and soils; stones, minerals and fossils; plants; animals; economics; and logistics. Every night each student added his report to whatever Linnaeus wrote. The last entries were dated 17 August, and when they returned to Falun, Linnaeus gave their Iter Dalecarlium to the governor. It was never published, but some account of the trip appeared in a Hamburg newspaper, and Linnaeus used some of their notes in later publications (Blunt 1971:76–79, Caddy 1886–1887, I:213–249).

Linnaeus did publish observations from subsequent field trips, and the book on his trip to Öland and Gotland in 1741 is also translated into English. The government (Swedish Estates of the Realm) asked him to make an economic survey, including natural history, of these islands. Accompanied by six young men, he departed from Stockholm on 15 May. It was quite cold, and Linnaeus suggested that “Spring should be measured according to climate and temperature rather than by the calendar”(Linnaeus 1973:23), and he then gave what we call phenological observations on the progress of the leaves and flowers or buds of several trees and herbs. Back in 1737 he had publicized a thermometer in the frontispiece to his Hortus Cliffortianus.

Fig. 9. Detail from frontispiece of Linnaeus, Hortus Cliffortianus (1737).

The thermometer was probably one he had obtained during three months spent in England, and he may have suggested to his friend Anders Celsius (1701–1744) that he reverse the scale he had developed, having boiling water at zero and freezing at 100 (Nordenmark 1935), because on 30 October 1758 Linnaeus wrote to a Montpellier botanist, Boissier de la Croix de Sauvages (English translation in Middleton 1966:100):

I was the first who decided to construct our thermometers in which the freezing point is 0, and the heat of boiling water 100; and this for the greenhouses of our garden.

Two subsequent dissertations were phenological: Vernatio Arborum (1753) and Calendarium Florae (1754), and are translated into English (Linnaeus 1775:133–158, 233–286, 1977).

When our explorers reached the copper smelter at Adelfors on 23 May 1741, Linnaeus noticed that the junipers looked like “trimmed cypresses”(Linnaeus 1973:34), which he attributed to smoke from the blast furnaces. Workers and residents at Adelfors complained about the air pollution. They reached Öland on 1 June, and Linnaeus made an inventory of its plants and animals. A gamekeeper told him the time of mating and the gestation periods of red and fallow deer, wild boar, and bear, which he recorded (Linnaeus 1973:48). He examined the nest of a Rook (Corvus frugilegus) containing three nestlings and numerous mites (Simulium reptans) bloated with nestlings’ blood. He counted annual rings of an oak stump and found it was 260 years old. Some rings were wider than others, which he thought was due to different severities of winters (Linnaeus 1973:58). Although modern botanists correlate annual ring width with summer moisture, this was a beginning of paleoclimatology. He knew that Francesco Redi had described 30 kinds of bird mites, which inspired Linnaeus (1973:69) to describe oystercatcher mites (Saemundssonia haematopi) and avocet mites (Vanellus vanellus). Along the seashore, he discovered that all plant species had succulent leaves, but that the majority of them growing elsewhere had ordinary dry leaves (Linnaeus 1973:72). Potentilla anserine grew on the sand and Senecio vulgaris on rotting seaweed. Cinnabar moths (Hipocrita jacobeae) were numerous on shore, and their larva ate the Senecio (Linnaeus 1973:86). He found that other plant species also had their own particular caterpillars, which he described and named, probably assisted by the entomologist Charles de Geer (Landin 1972), whom he visited at Medevi on 23 August (Linnaeus 1973:89, 199). Near the Lummelunda church he studied a marsh in which the sedge Cladium mariscus grew. This species had not previously been reported in Sweden; he emphasized the facts that cattle ate it in early spring and that it made good thatch for roofs. Since he learned that it grew in a former lake, he suggested that it be planted in Sweden’s many “sterile and useless bogs” that could not be drained (Linnaeus 1973:113). Beyond Stenkyrka, he found under stones in water a white oval leech (Hirundo [Nephelis] octoculata) that could also be found in the stomachs of small fishes, and he thought that the liver worms of sheep were probably the “spawn” of this leech, which the sheep swallowed when grazing in marshy places (Linnaeus 1973:118–119). After transcribing runic inscriptions in the Hangvar churchyard on 27 June, he commented that a white lichen (Kecabira cakcarea) grew on the limestone tombstones but not on granite ones (Linnaeus 1973: 119).

They reached Fårö Island, just north of Gotland and much smaller (see map, Linnaeus 1973:facing page 109), on 28 June. Its inhabitants hunted seals but not porpoises. They also ate eider and their eggs, but Linnaeus thought that “The time will probably come when the excellent down of these birds will save them from being shot” (Linnaeus 1973:126), but he did not explain how to collect it (possibly from their nests). He described in some detail the growth of “sandhafre” (Ammophila arenaria) on the sand dunes, and explained how it stabilized the dunes. He also found ant lions on the dunes that were “far more multicoulored than on Öland” (Linnaeus 1973:130). He referred the reader to Réaumur’s memoir on ant lions for details.

Five years later, from 12 June to 11 August 1746, Linnaeus traveled through West Gothland and published his findings in Wästgöte-Resa (1747). Caddy (1886–1887, II:165–206) summarized this book, turning it into a Linnaean travelogue (she followed his route). Among the translated extracts quoted by Blunt (1971:163) is this generalization:

…when animals die they are converted into mould, the mould into plants. The plants are eaten by animals, thus forming the animals’ limbs, so that the earth, transmuted into seed, then enters man’s body as seed and is changed there by man’s nature into flesh, bones, nerves, etc.; and when after death the body decomposes, the natural forces decay and man again becomes that earth from which he was taken.

These thoughts were not especially original (Isaiah 40:6 “All flesh is grass.”), but they are of interest as a prelude to the 1749 dissertation on the economy of nature.

Meanwhile, in 1744, the dissertation Oratio de telluris habitabilis incremento (On the increase of the habitable earth), defended by Johann Westmann, offered a novel geological theory (Frängsmyr 1983) and explanation of how the world had become populated with species (Linnaeus 1781:71–127, 1977b): (1) God created one pair of each sexual species and one individual of each hermaphroditic species; (2) since Adam named all species, the Garden of Eden must have been a mountain island; (3) each species increased in numbers every generation; (4) as they increased, they enlarged the geographical area they inhabited; and (5) the habitable land increased as the numbers of organisms increased. To support this argument, Linnaeus had to demonstrate the potential of all species to increase their populations. He listed the numbers of seeds reported for different flowers: Helenium 3000, Zea 2000, Helianthus 4000, Papaver 3200, and Nicotina 40,320. He then calculated correctly that an annual plant that only produced two seeds per year, if preserved from animals and accidents, would have 1,048,576 descendants in 20 years. That dissertation was only one of several publications that entitle Linnaeus to be called the founder of plant geography (Hofsten 1916:243–247, Browne 1983:16–23). Du Rietz (1957a) summarized his contributions to alpine phytogeography, paludology (on which see also Du Rietz 1957b), indicator plants, plant succession, limnology, and forest geography.

A fundamental difference between Linnaeus’ conception of an ecological science and ours is that in his, biotic interrelationships were designed by God to work harmoniously and permanently and for the benefit of humanity (Hofsten 1957:90–102), whereas in ours, interrelationships evolve and can lead to extinction of species. His conception was part of a general outlook in science: for example, in astronomy, celestial bodies were unchanging in substance and orbits; and in geology, ongoing changes in the landscape were considered minor compared to the changes caused by God in the Flood of Noah. Scientists’ study of a “static” universe gradually revealed that it is not static. This even happened to Linnaeus. In his Systema Naturae (1735, 1964) he confidently claimed that all species had been created by God at the beginning and no new ones had since appeared. However, the discovery of Peloria in 1741—so similar to Linaria, yet an apparently different species—shook his belief in the constancy of species. He eventually suspected that God had created only a few species, which later hybridized to form the great variety now seen (Hagberg 1952:196–205, Hofsten 1957:65–86, Larson 1971:94–121, Bowler 1989:64–68). On 18 August 1764, he explained this idea in a letter to Johannes Burmann (in Nicolas 1963:53).

Let us suppose God made a Ranunculus [and that] this species is crossed with a Helleborus, and Aquilegia, or a Nigella in hybrid generations. Through Divine Law the descendants of these hybrids will have, as in animals, the mother’s medulla and father’s cortex. As a result, there are so many of Ranuncula with either aquilegous leaves or nigellous ones that you could not separate them into arbitrary genera…

Linnaeus’ term “oeconomia naturae” (1749) is rather similar to the contemporary term for animal physiology, “animal economy,” which involved studying how the parts contributed to the functioning of the whole. He may have implied an analogy between organs in an animal and species in a biotic community (Linnaeus 1775:39, 1977a):

By the Oeconomy of Nature we understand the all-wise disposition of the Creator in relation to natural things, by which they are fitted to produce general ends, and reciprocal uses.

Having a passion for system, Linnaeus approached the economy of nature systematically. For each of the three kingdoms—stones (and soils), plants, and animals—he discussed a cycle of propagation, preservation, and destruction.

Surveying different kinds of stones under “Propagation,” he suggested that one or more kinds had organic origins (Linnaeus 1775:51, 1977):

…testaceous bodies and petrifactions resembling plants were once real animals or vegetables; and it seems likely that shells being of a calcareous nature have changed the adjacent clay, sand, or mould into the same kind of substance. Hence we may be certain, that marble may be generated from petrifactions, and therefore it is frequently seen full of them.

Under “Preservation,” he speculated, inaccurately, on how stones are generated and augmented by water, but under “Destruction” he was more accurate in describing the actions of weather and water in the gradual erosion of rocks. He also noted that certain animals also helped erode some kinds (Linnaeus 1775:57, 1977):

[Testaceous worms]…eat away the hardest rocks. That species of shell fish called the razor shell bores thro’ stones in Italy, and hides itself within them; so that the people who eat them are obliged to break the stones, before they can come at them. The cochlea F[auna] S[vecica number] 1299. a kind of snail that lives on craggy rocks, eats, and bores through the chalky hills, as worms do through wood. This is made evident by the observations of the celebrated de Geer.

God allegedly designed living beings to both survive and regulate each other (Linnaeus 1775:40, 1977):

…all living creatures should constantly be employed in producing individuals; that all natural things should contribute and lend a helping hand to preserve every species; and lastly, that the death and destruction of one thing should always be subservient to the restitution of another.

This explicit statement was an important contribution to the balance of nature concept, though Linnaeus did not name it (Egerton 1973:335–337).

Under plant propagation, he discussed sexual reproduction, then seed dissemination (Linnaeus 1775:64–65, 1977):

Berries and other pericarps, are by nature allotted for aliment to animals, but with this condition, that while they eat the pulp they shall sow their seeds; for when they feed upon it they either disperse them at the same time, or, if they swallow them, they are returned with interest; for they always come out unhurt. It is not therefore surprising, that if a field be manured with recent mud or dung not quite rotten, various other plants, injurious to the farmer, should come up along with the grain, that is sowed.

Under “Preservation,” he claimed that God had decreed (Linnaeus 1775:67–68, 1977): “that the whole earth should be covered with plants, and that no place should be void, none barren.” He had heard of deserts but had never seen one, so he confidently asserted that they have their own unique trees and herbs (which they do, but there is still bare ground). All environments—alpine, grassland, marshes, aquatic, deserts—have characteristic species, and he discussed examples. The graesmasken moth inhibits the spread of grass, leaving room for other plants. However, plants die, and their destruction is also part of God’s plan. Black mould, which nourishes new plants, comes from dead plants, and that cycle really begins with the liverworts that grow on bare rocks; when they die, they leave mould for mosses, and as mosses die, they leave mould for herbs and shrubs. This dissertation contains one of the earliest descriptions of plant succession (which Clements, 1916:10, credited to Biberg, the defendant). Insects contribute to the death of plants by eating parts, which make them vulnerable to other hazards (Linnaeus 1775:76–80, 1977).

Under animal propagation, Linnaeus surveyed all the known reproductive habits of different species, and although he rejected spontaneous generation, he admitted that (Linnaeus 1775:89),

The laws of generation of worms are still very obscure, as we find they are sometimes produced by eggs, sometimes by offsets, just in the same manner as happens to trees.

He pointed out that smaller animals tend to produce more offspring than larger ones: mites can increase to a thousand in a few days, but elephants only produce one offspring in two years. However, some hawks are smaller than the poultry they eat, and he acknowledged that hawks layer fewer eggs, without attempting to explain why. He calculated that two pigeons breeding nine times a year could produce 14,672 young in four years, but his translator pointed out that Linnaeus had mistakenly added in the original pair to reach this figure (Linnaeus 1775:90, 1977); however, the numbers 6 and 7 were accidentally transposed in the English edition; Linnaeus’ figure should have been 14,760 (Egerton 1967:174). In Politia Naturae (Latin, 1760, cited from the English translation, 1781:162, 1977b), he added that long-lived animals propagate slowly.

Under animal preservation, he discussed which species care for their young and which do not. Among polygamous species, “males scarcely take any care of the young” (Linnaeus 1775:93, 1977a), and cuckoos lay their eggs in the nests of wagtails and hedge-sparrows. Because of the great diversity of species, God assigned each one certain places to live and certain foods to eat. Linnaeus gave a brief survey of examples from the animal kingdom, but only provided details concerning the mutualism between the bivalve, Pinna, and the crab, Pinnotheres (Linnaeus 1775:111–113, 1977a). This relationship had been reported by Aristotle (Historia Animalium 547b16–17), but had been neglected by more modern naturalists until Linnaeus’ disciple, Fredrik Hasselqvist (1722–1752), traveled to the eastern Mediterranean (where he died) and confirmed it. Since this Oeconomia naturae dissertation was published in March 1749, and Hasselqvist did not leave Stockholm until 7 August 1749 (Blunt 1971:183–185), Linnaeus obviously added these comments on Pinna and Pinnotheres before the dissertation was republished in Amoenitates Academica, volume 2 (1751), the source of Benjamin Stillingfleet’s English translation.

Linnaeus’ survey of the destruction of animals included two food chains, one terrestrial and one aquatic (Linnaeus 1775:114, 1977a):

…the tree-louse lives upon plants. The fly called musca aphidivora lives upon the tree-louse. The hornet and wasp fly upon the musca aphidivora. The dragon fly upon the hornet and wasp fly. The spider on the dragon fly. The small birds on the spider. And lastly, the hawk kind on the small birds.

In like manner the monoculus delights in putrid water, the knat eats the monoculus, the frog eats the knat, the pike eats the frog, the sea calf eats the pike.

Next, he emphasized the importance of predators to prevent their prey from over-running everything, and the importance of scavengers to prevent the earth from being overwhelmed with carcasses (Linnaeus 1775:114–122, 1977a).

In 1734, while exploring Dalecarlia, Linnaeus had watched his expedition’s horses grazing certain plants and avoiding others. Both John Ray and René Réaumur had reported insects having very specific food plants (Egerton 2005:303 and 2006: ), but in the late 1740s Linnaeus and some students (eight named, plus others) ran 2314 experiments on livestock to determine their plant preferences. Their findings were reported in a dissertation entitled Pan Svecius (Latin 1749, cited from Stillingfleet translation: Linnaeus 1775:361, 1977a):

This was one of the earliest, if not the earliest, series of experiments on an ecological question, and surely the earliest such large-scale quantitative experiments. (Stillingfleet’s translation did not include all details in the original; more is translated in Ramsbottom 1959:162–167.) The reason for so many experiments was that, unlike the insects observed by Ray and Réaumur, these mammals were not limited to eating one or two species, but nevertheless were somewhat selective. Allegedly, God’s reason to make various animal species eat different plant species was to prevent some plant species from becoming extinct due to overeating and others from becoming too abundant because they were not eaten (Linnaeus 1775:347–349, 1977a). Also, in “Oeconomy of Nature”(1775:99–100, 1977a) Linnaeus mentioned “an oeconomical experiment well known to the Dutch,” of which he perhaps learned while he was in the Netherlands in 1735,

that when eight cows have been in a pasture, and can no longer get nourishment, two horses will do very well there for some days, and when nothing is left for the horses, four sheep will live upon it.

In 1774 a dissertation comparable to Pan Svecius appeared on the subject of plants and animals eaten by chickens, ducks, and geese, Esca Avium Domesticarum (Smit 1979:122).

Linnaeus’ second most important dissertation for ecology is Politia Naturae (1760), translated into English as ”On the Police of Nature” (1781:129–166). It is on the struggle and survival of species, including humans. A pessimistic conclusion that he drew about humans seemed also to apply to some extent to plant and animal species. Unfortunately, F. J. Brand, the English translator of this dissertation, omitted it. Fortunately, Alan Blair translated it in Kurt Hagberg’s biography of Linnaeus (1952:183).

…where the population increases too much, concord and the necessities of life decrease, and envy and malignancy towards neighbours abound. Thus it is a war of all against all!

The point of the dissertation was to explain why a war of all against all (competition) did not lead to extinction. A major reason was what we call ecological diversity: each species is confined to its own “station” (habitat). Sweden had about 1300 plant species, but only about 50–100 are in any one place (Linnaeus 1781:133, 1977b). Linnaeus argued that although it is received opinion that plants were created for the use of animals, actually, animals were created to regulate plants’ abundance. As proof, he cited numerous insect species that only eat a single plant species, doves eat surplus seeds, and other birds, bats, and anteaters eat insects to prevent them from consuming all of the plants they eat, and so on.

Linnaeus had a lifelong fascination with insects. Five of the dissertations translated by Brand were on insects and their interactions with other species of plants and animals (Linnaeus 1781:309–456, 1977b). Smit (1979:125) even claimed that Linnaeus made a major contribution to entomology, as evidenced by his Fundamenta Entomologiae (1767). If so, that dissertation was important because it synthesized briefly the works of others. Linnaeus praised as “immortal” the treatise by Réaumur, whom he had met in Paris, and he once sent Réaumur the eggs of the alpicola butterfly (Papilio Apollo). Réaumur’s thank-you note is published in Linnaeus’ correspondence (Smith 1821, II:477–479). However, Linnaeus also pointed out the necessity of providing official names for the species Réaumur had studied (Linnaeus 1772:13). Despite Linnaeus’ strong interest in both insects and plants, he never fully appreciated the role insects play in pollination, except for fig trees. He first named the nectary of flowers in 1735, and he did move from a belief that bees harm flowers by collecting nectar, to a belief that they help pollinate flowers, but never realized their crucial importance for flowers that are not wind pollinated (Miall 1912:322–324, Usinger 1964:6, Lorch 1978:518, 523, Eriksson 1983:105). He did, however, appreciate the danger of accidentally introducing American insect pests when American plants were brought to Europe. In 1739 he confessed to having brought American trees from England to the Netherlands in August 1736; these harbored aphids, which multiplied in a greenhouse and then escaped into botanical gardens in Amsterdam and Leiden (1781:325, 1977b). Pehr Kalm brought pea seeds when he returned to Sweden in 1751; he discovered that they contained live Dermestes pisorum insects, which he captured. However, Linnaeus warned against the danger of artificial introductions (Linnaeus 1781:386–387, 1977).

Linnaeus, physician and sometime professor of medicine, followed Richard Bradley (Egerton 2006:124–125) in arguing that minute organisms, “even smaller than the motes dancing in a beam of light”(Linnaeus quoted in translation from Smit 1979:123) transmit contagious diseases. He developed his argument in two dissertations, Exanthemata viva (1757) and Mundus invisibilis (1767). He also discussed and described parasitic worms. His speculations (1973:118–119) about some free-living worms being a different stage of internal parasitic worms was a reasonable hypothesis, but he supported it with unverified (and incorrect) examples (Foster 1965:32, Grove 1990:4, 40, 106, 386).

Linnaeus clearly deserves a prominent place among the founders of ecology, but was this a case like Mendel’s, in which his findings were only appreciated after others had rediscovered his basic ideas? No—many of his writings and the student dissertations were reprinted and translated into other languages, and contemporary and later naturalists, including Gilbert White and Charles Darwin, read them (Stauffer 1960, Limoges 1980).

Literature cited

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Bowler, P. J. 1989. Evolution: the history of an idea. University of California Press, Berkeley, California, USA.

Broberg, G. 2000. Carl Linnaeus, 1707–1777, Swedish naturalist and physician. Pages 417­–418 in A. Hessenbruch, editor. Reader’s guide to the history of science. Fitzroy Dearborn, London, UK.

Browne, J. 1981. The secular ark: studies in the history of biogeography. Yale University Press, New Haven, Connecticut, USA.

Caddy, F. 1886–1887. Through the fields with Linnaeus. Two volumes. Longmans, Green, London, UK.

Clements, F. E. 1916. Plant succession: an analysis of the development of vegetation. Carnegie Institution of Washington, Washington, D.C., USA.

Du Rietz, G. E. 1957a. Linnaeus as a phytogeographer. Vegetatio 7:161–168.

Du Rietz, G. E. 1957b. Linné som myrforskare. (English summary, pages 60–68.) Uppsala Universitets Årsskrift 5:1–80.

Egerton, F. N. 1967. Observations and studies of animal populations before 1860: a survey concluding with Darwin’s Origin of Species. Dissertation. University of Wisconsin-Madison, Madison, Wisconsin, USA.

Egerton, F. N. 1973. Changing concepts of the balance of nature. Quarterly Review of Biology 48:322–350.

Egerton, F. N. 2005. A history of the ecological sciences, part 18: Francis Willughby and William Derham. ESA Bulletin 86:301–313.

Egerton, F. N. 2006a. A history of the ecological sciences, part 20: Richard Bradley, entrepreneurial naturalist. ESA Bulletin 87:117–127.

Egerton, F. N. 2006b. A history of the ecological sciences, part 21: Réaumur and his history of insects. ESA Bulletin 87:212–224.

Ericksson, G. 1983. Linnaeus the botanist. Pages 63–109 in T. Frängsmyr, editor. Linnaeus: the man and his work. University of California Press, Berkeley, California, USA.

Foster, W. D. 1965. A history of parasitology. E. and S. Livingstone, Edinburgh, UK.

Frängsmyr, T. 1983. Linnaeus as a geologist. Pages 110–155 in T. Frängsmyr, editor. Linnaeus: the man and his work. University of California Press, Berkeley, California, USA.

Fries, R. E. 1950. A short history of botany in Sweden. Almqvist and Wiksells, Uppsala, Sweden.

Goerke, H. 1993. Linnaeus. D. Lindlley, translator. Charles Scribner’s Sons, New York, New York, USA.

Grove, D. I. 1990. A history of human helminthology. C.A.B International, Wallingford, UK.

Hagberg, K. 1952. Carl Linnaeus. Alan Blair, translator. Jonathan Cape, London, UK.

Hofsten, N. von. 1916. Zur älteren Geschichte des Diskontinuitätsproblems in der Biogeographie. Zoologische Annalen 7:197–353.

Hofsten, N. von. 1957. Linnaeus’s conception of nature. Kungliga Vetenskaps– Societetens Årsbok, 65–105.

Hulth, J. M. 1907. Bibliographia Linnaeana: matériaux pour server a une bibliographie Linnéenne. [Chronological order.] C. J. Lundström, Uppsala, Sweden.

Jackson, B.D. 1913. Authorship in the “Amoenitates Academicae.” Journal of Botany 51:101–103, 244.

Kiger, R. W., C. A. Tancin, and G. D. R. Bridson. 1999. Index to scientific names of organisms cited in Linnaean dissertations: together with a synoptic bibliography of the dissertations and a concordance for selected editions. Hunt Institute for Botanical Documentation, Pittsburgh, Pennsylvania, USA.

Koerner, L. 1999. Linnaeus: nature and nation. Harvard University Press, Cambridge, Massachusetts, USA.

Landin, B.-O. 1972. Charles de Geer (1720–78). Dictionary of Scientific Biography 5:328–329.

Larson, J. L. 1971. Reason and experience: the representation of natural order in the work of Carl von Linné. University of California Press, Berkeley, California, USA.

Limoges, C. 1974. Economie de la nature et idéologie juridique chez Linné. Thirteenth International Congress for the History of Science (Moscow 1971) Proceedings, Section 9: 25–30.

Limoges, C. Dec.1980. De l’économie de la nature aux ecosystemes: l’histoire de l’écologie esquissée à grands traits. Spectre: 9–14.

Lindroth, S. 1973. Carl Linnaeus (or von Linné), 1707–1778. Dictionary of Scientific Biography 8:374–381.

Lindroth, S. 1983. The two faces of Linnaeus. Pages 1–62 in T. Frängsmyr, editor. Linnaeus: the man and his work. University of California Press, Berkeley, California, USA.

Linnaeus, C. 1735. Systema naturae, sive regna tria naturae systematice proposita per classes, ordines, genera, & species. Theodorum Haak, Leiden, The Netherlands.

Linnaeus, C. 1737a. Flora Lapponica exhibens plantas per Lapponiam. Salomonem Schouten, Amsterdam, The Netherlands.

Linnaeus, C. 1737b. Hortus cliffortianus: plantas exhibens quas in hortistam vivis quam siccis, Hartecampi in Hollandia, coluit virnobillismus & generosissimus Georgius Clifford. Amsterdam, The Netherlands.

Linnaeus, C. 1739. Om renarnas brömskulor i Lapland. Kungliga Svenska Vetenskaps Akademien Handlingar 1:121–132.

Linnaeus, C. 1740. Anmarking öfwer de diuren, som sagas kåmma neder utur skyarna i norrige. Kungliga Svenska Vetenskaps-Akademien Handlingar 1:326–331. For later editions and translations, see Soulsby numbers 1112–19.

Linnaeus, C. 1746a. Fauna svecica sistens animalia Sveciae regni. Salvii, Stockholm, Sweden.

Linnaeus, C. 1746b. Oestrus rangiferinus descriptus. Acta Societatis Scientiarum Upsaliensis, for 1741, 102–115.

[Linnaeus, C.] 1775. Miscellaneous tracts relating to natural history, husbandry, and physick. To which is added the calendar of flora. B. Stillingfleet, translator. Edition 3. J. Dodsley, Baker and Leigh, London, UK.

[Linnaeus, C.] 1781. Select dissertations from the Amoenitates Academicae. F. J. Brand, translator. G. Robinson and J. Robson, London, UK.

Linnaeus, C. 1811. Lachesis Lapponica, or a tour in Lapland. C. Troilius, translator. J. E. Smith, editor. Two volumes. White and Cochrane, London, UK.

Linnaeus, C. 1964. Systema naturae 1735: facsimile of the first edition with an introduction and a first English translation of the “Observationes.” M. S. J. Engel- Ledeboer and H. Engel, translators. B. de Graaf, Nieuwkoop, The Netherlands.

Linnaeus, C. 1971. A tour in Lapland. [Reprint of Linnaeus 1811.] Arno Press, New York, New York, USA.

[Linnaeus, C.] 1972. L’équilibre de la nature. B. Jasmin, translator. C. Limoges, introduction and notes. Vrin, Paris, France.

Linnaeus, C. 1973. Linnaeus’s Öland and Gotland Journey, 1741. M. Åsbert and W. T. Stearn, translators. W. T. Stearn, introduction. Academic Press, London, UK.

[Linnaeus, C.] 1977a. Miscellaneous tracts relating to natural history, husbandry, and physick. B. Stillingfleet, translator. [Reprint of Linnaeus 1775.] Arno Press, New York, New York, USA.

[Linnaeus, C.] 1977b. Select dissertations from the Amoenitates Academicae. F. J. Brand, translator. [Reprint of Linnaeus 1781.] Arno Press, New York, New York, USA.

Linnaeus, C. 1979. Travels. David Black, editor. Stephen Lee, illustrations. Charles Scribner’s Sons, New York, New York, USA.

Lorch, J. 1978. The discovery of nectar and nectarines and its relation to views on flowers and insects. Isis 69:514–533.

Mayr, E. 1982. The growth of biological thought: diversity, evolution, and inheritance. Harvard University Press, Cambridge, Massachusetts, USA.

Merriam, D. F. 2004. Carolus Linnaeus: the Swedish naturalist and venerable Traveler. Earth Sciences History 23:88–106.

Miall, L. C. 1912. The early naturalists: their lives and work (1530–1789). Macmillan, London, UK.

Middleton, W. E. K. 1966. A history of the thermometer and its use in meteorology. Johns Hopkins Press, Baltimore, Maryland, USA.

Morton, A. G. 1981. History of botanical science: an account of the development of botany from ancient times to the present day. Academic Press, London, UK.

Müller-Wille, S. 2003. Nature as a marketplace: the political economy of Linnaean botany. Pages 154–172 in M. Schabas and N. de Marchi, editors. Oeconomies in the age of Newton. Duke University Press, Durham, North Carolina, USA.

Nicolas, J.-P. 1963. Adanson, the man. Volume I. Pages 1–121 in G. H. M. Lawrence, editor. Adanson: the bicentennial of Michel Adanson’s “Familles des plantes.” Hunt Botanical Library, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.

Nordenmark, N. V. E. 1935. Anders Celsius, Linné, och den hundragradiga thermometern. Svenska Linné-Sällskapets Årsskrift 18:124–133.

Ramsbottom, J. 1959. Caroli Linnaei pan suecicus. Botanical Society of Edinburgh Transactions 38:151–167.

Rausing, L. [Koerner]. 2003. Underwriting the oeconomy: Linnaeus on nature and mind. Pages 282–308 in M. Schabas and N. de Marchi, editors. Oeconomies in the age of Newton. Duke University Press, Durham, North Carolina, USA.

Schramm, E. 1984. Linné, Gedner und die biologische Kontrolle. Medinin historisches Journal 19:244–249.

Smit, P. 1979. The zoological dissertations of Linnaeus. Svenska Linnésällskapets Årsskrift for 1978, 118–136.

Smith, J. E., editor. 1821. A selection of the correspondence of Linnaeus, and other naturalists, from the original manuscripts. Longman, Hurst, Rees, Orme, and Brown, London, UK.

Soulsby, B. H. 1933. A catalogue of the works of Linnaeus (and publications more immediately relating thereto) preserved in the libraries of the British Museum. [Topical order.] Edition 2, British Museum, London, UK

Spary, E. C. 2002. Carolus Linnaeus (Carl Linnaeus, Carl von Linné:1707–78), Swedish naturalist. Volume 2. Pages 410–413 in A.C. Kors, editor. Encyclopedia of the Enlightenment. Oxford University Press, Oxford, UK.

Stafleu, F. A. 1971. Linnaeus and the Linnaeans: the spreading of their ideas in systematic botany. Oosthoek, Utrecht, The Netherlands.

Stauffer, R. C. 1960. Ecology in the long manuscript version of Darwin’s Origin of species and Linnaeus’ Oeconomy of nature. American Philosophical Society Proceedings 104:235–241.

Usinger, R.L. 1964. The role of Linnaeus in the advancement of entomology. Annual Review of Entomology 9:1–16.

Acknowledgments

For their assistance I thank Jean-Marc Drouin, Muséum National d’Histoire Naturelle, Paris; and Anne Marie Drouin-Hans, Université de Bourgogne.

Frank N. Egerton
University of Wisconsin-Parkside
Kenosha WI 53141
E-mail: [email protected]

ESA Statement on Massachusetts et al. vs. U.S. Environmental Protection Agency,
“The Certainty of Global Climate Change”

In response to the U.S. Environmental Protection Agency’s (EPA) argument in the U.S. Supreme Court case, Massachusetts et al. vs. U.S. EPA et al. that it would not regulate carbon dioxide due in part to scientific uncertainty, Alan Covich, President of the Ecological Society of America, the nation’s premier scientific society of ecological scientists, expressed dismay over the agency’s disregard for the widespread scientific consensus on the facts and effects of climate change. Covich said, “ESA strongly supports the scientific arguments regarding the certainty of climate change made by Massachusetts et al. as legitimate and accurate.”

The case currently before the Supreme Court was brought by a group of states, cities, and nonprofits, which argued that, under the Clean Air Act (CAA), carbon dioxide is a pollutant and contributor to climate change, and as such, the EPA must regulate carbon dioxide emissions. EPA argues, however, that it does not have the authority to regulate carbon dioxide and even if it had, the agency would not regulate carbon dioxide due in part to scientific uncertainty. The court’s decision will determine whether the CAA mandates that EPA regulate carbon dioxide, which may be a watershed decision for U.S. action regarding climate change.

The CAA states that absolute scientific certainty is not necessary for regulation of a pollutant. Instead, the pollutant must “reasonably be anticipated to endanger public health or welfare.” [Section 202(a)(1)] In arguing that carbon dioxide cannot reasonably be anticipated to endanger public health or welfare due to scientific uncertainty, EPA chose only the points highlighting the absence of certainty from the 2001 National Research Council Report on climate change, but disregarded a general scientific consensus that climate change is indeed occurring. While certain facets of climate are less certain than others, current scientific understanding verifies and supports the following statements:

• The physics of the greenhouse effect are well understood by scientists. Certain atmospheric gases (including carbon dioxide) absorb radiation, causing a warming effect, and that greater concentrations of these gases will lead to an increase in surface temperatures ( Energy Information Administration 2004).

• It is certain that human activities have increased the concentrations of carbon dioxide in the atmosphere above levels in the geologically recent historical record, which has led to the recent global climate change. Carbon dioxide levels remained constant from the period 1000–1750, then increased more than 25% in the last 150 years ( International Panel on Climate Change 2001, Energy Information Administration 2004). This had caused average global surface temperatures to rise approximately 0.6ºF; global average sea level to rise 0.1–0.2 meters; and ice extent in the Arctic to decrease by about 40% ( National Assessment Synthesis Team, U.S. Global Change Research Program 2000; International Panel on Climate Change 2001).

• It is virtually certain that greenhouse gas emissions, continued at the current rate, will cause additional warming. At the current emissions rate, carbon dioxide levels will double by 2100, leading to a likely temperature increase of 2.7º–10.4ºF ( National Assessment Synthesis Team, U.S. Global Change Research Program 2000; International Panel on Climate Change 2001).

• Climate change will increase threats to human health, especially in developing countries and lower income populations. Further increases in surface and ocean temperatures will cause an increase in drought, flood, and hurricane intensities, disrupt agricultural production, and expand the range of disease vectors ( National Assessment Synthesis Team, U.S. Global Change Research Program 2000; International Panel on Climate Change 2001).

• The ecological effects of climate change are already observable and have been well-documented. Ecosystem disruptions including fire, drought, invasion of species, habitat shifts and coral bleaching events result in reduced biodiversity, increased extinction risk, and loss of ecosystem services ( National Assessment Synthesis Team, U.S. Global Change Research Program 2000; International Panel on Climate Change 2001).

• The exact timing and magnitude of climate change depend on climate inertia and future emission rates. The elevated greenhouse gases currently in the atmosphere will continue to change the climate for an unknown period, even if all emissions are capped immediately. However, capping carbon dioxide emissions will significantly increase the timing of climate stabilization ( Committee on the Science of Climate Change, National Research Council 2001; International Panel on Climate Change 2001).

• It is likely that significant, intense, and abrupt events caused by climate change (such as local heat waves, intense droughts, or floods) will occur. The absence of a complete understanding of certain global processes may prevent predictions of events, including thermohaline circulation reduction, significant losses to Antarctic ice sheet, and altered Asian monsoons ( National Assessment Synthesis Team, U.S. Global Change Research Program 2000; International Panel on Climate Change 2001).

Although current scientific understanding, by definition, constantly changes, these statements represent the latest information and are supported by a wide group of climate scientists. Many other scientific bodies, including the American Geophysical Union (AGU), the Geological Society of America (GSA), and the joint National Academies of Science (NAS), have issued similar statements:

AGU: ‹http://www.agu.org/sci_soc/policy/positions/climate_change.shtml›

GSA: ‹http://www.geosociety.org/aboutus/position10.htm›

NAS: ‹http://nationalacademies.org/onpi/06072005.pdf›

Said Covich, “Communication and widespread awareness of climate change information remains essential not only to conservation of natural resources, but also to the general well-being of the nation. The recognition of these facts by the Court in Massachusetts et al. vs. U.S. EPA et al. will provide significant support to the certainty of climate change that the administration cannot ignore.”

Literature cited

National Assessment Synthesis Team, U.S. Global Change Research Program. 2000. Climate change impacts on the United States. 18 October 2006. ‹http://www.usgcrp.gov/usgcrp/Library/nationalassessment/overviewfindings.htm›

Committee on the Science of Climate Change, National Research Council. 2001. Climate change science: an analysis of some key questions. 18 October 2006. ‹http://newton.nap.edu/execsumm_pdf/10139.pdf›

International Panel on Climate Change. 2001. Climate Change 2001: Synthesis Report. 16 October 2006. ‹http://www.grida.no/climate/ipcc_tar/vol4/english/index.htm›

Energy Information Administration. 2004. Greenhouse gases, climate change, and energy. ‹http://www.eia.doe.gov/oiaf/1605/ggccebro/chapter1.html›

Contact: Nadine Lymn (202) 833-8773 x205; [email protected]

or Annie Drinkard (202) 833-8773 x211; [email protected]

Public Affairs Office
1707 H Street NW, Suite 400
Washington, DC 20006
Web: ‹www.esa.org/pao›

Note: Dr. Harold Ornes is the editor of Ecology 101. Anyone wishing to contribute articles or reviews to this section should contact him at the Office of the Dean, College of Science, Southern Utah University, 351 W. Center, Cedar City, UT 84720; (435) 586-7921; Fax: (435) 865-8550; E-mail: [email protected].

Whether you are teaching undergraduate or graduate-level field ecology, or you are a full-time researcher and in the midst of gleaning the maximum amount of information from your most recent field research sampling trip, I think you will agree that we almost never remember everything needed in the field, and likewise almost never have a perfectly smooth and uneventful field trip or season. Thanks to Carmen Wong, University of British Columbia, we can take a few moments, sit around the fire, feel her pain, and start planning for next season.

I would encourage you to share one or two of your field season horror stories with your peers through this column.

Preparing for the Field Season

I thought I was entering the field season for my Ph.D. research in good shape. I had over 5 years of experience as a consultant working on various field research projects. And, I had spent time in the field during my Master’s research ziplocking grizzly bear feces in the Yukon. So, as a seasoned field biologist embarking on my Ph.D. research, I finally had my research permit in place, lined up two great field assistants, and purchased several boxes of waterproof paper and printed colored maps of my potential study sites. But, I should have known that you can never be too prepared for fieldwork.

My first challenge was losing a field assistant on the first day. I didn’t actually lose him in the forest; rather, he took a permanent job with a consulting company. My promise of helicopter rides in the Rockies could not compare to a decent salary with health benefits. I spent the next month looking for another field assistant. It turns out the good candidates get snapped up early.

My second challenge was with my sampling design. I had wanted to use stratified random selection of stands containing whitebark pine in order to describe dynamics across large landscapes. Random selection using a vegetation inventory and GIS had worked in a pilot study the year before in another park. Using my beautiful colored maps, my remaining field assistant and I spent a week bushwhacking to mountaintops, only to find no whitebark pine where it was suppose be. It seems that I was mistaken in my assumption that I was using a vegetation inventory. An inventory did not exist and I was actually using a coarse-grain classification. Polygons indicated only a potential for containing whitebark pine … and clearly that potential was low. It turns out that having the home number of a biometrician is handy when one is revising a sampling design in the field.

My third challenge was in vexing the park wardens. We left the door of a warden cabin in the backcountry unlocked. We almost lost the privilege of using these cabins, which would have made my research impossible, but luckily the supervisory warden was understanding. It was clear, however, that a moment of carelessness can jeopardize one’s research.

So what should you walk away with after reading the above tales? Here are a few lessons I learned this summer that may help you during your next field project:

1. Apply early for your research permits. I knew of a Masters’ student who spent the entire summer waiting for his research permit and was not able to collect any data. As an example, it takes over 6 months to go through the application process to work in the provincial parks of Alberta and British Columbia in Canada. If you want to handle wildlife or do destructive sampling, count on much longer.
   
2. Make contacts with the relevant organizations . It is very likely that people are interested in your research and can contribute expertise. This summer numerous people in Parks Canada helped locate whitebark pine stands and gave ideas on how to apply my research results to management recommendations. Organizations such as protected area agencies or forestry companies are also often able to offer significant in-kind support. By contacting the right people, I was able to tag along on the survey flights of the fire crew; these flights saved us days of hiking and innumerable dollars.
   
3. Understand your sampling scheme. A pilot study is critical. Pilot data can indicate the amount of variability you can expect and thus guide you on your sampling intensity. If you can’t do a pilot study, then I recommend at least trying a couple of days in the field with your supervisor. Even the best methods devised in the office will be modified in the field due to some unforeseen variable. If your supervisor can’t come out, work together through different scenarios of what could affect your sampling plan and derive alternate methods. If possible, having the home phone number of your supervisor could prove useful. Both my supervisor and the biometrician on my committee were indispensable in the first 2 weeks of my field season. Decisions about what is done in the field take only a second to make. However, the statistical consequences of that decision could be untenable down the road.
   
4. Be safe . After working in the private sector and returning back to the university environment, I was appalled by how little attention most supervisors give to safety in field. There are crazy true stories of graduate students working in the backcountry with chainsaws with no means of communication and a 30-km hike to the nearest road. The most dangerous situation my field crew and I faced this summer was a bout of food poisoning. Normally, this would not have been a big deal, except we were 26 km from the nearest road and the day we hiked out was one of the hottest days of the summer. Take your responsibility as a crew leader seriously. At minimum, this means having safety protocol discussions with your field crew, regular check-ins at the end of the day, a regulation first aid kit (an Epi-pen would not be excessive), first aid training, and either a radio or a satellite phone with the relevant emergency contact numbers. If your supervisor is as smart as mine, they should provide these to you without question. Furthermore, educate yourself on the guidelines to be followed in order for compensation to be paid for injuries on the job.
   
5. Treat your field assistants well. Pay your field assistants well, which means paying them at least or above the average wage for field assistants. If you cannot afford this, then try to compensate with providing room and board. Feed your field assistants well because food makes people happy. Budget at least $10/person per day and do not complain if they want to look for fresh basil in the middle of small-town Alberta. Most important, be flexible to their needs, within reason, of course. Often fieldwork requires people to work long hours and weekends on a project they probably do not love as much as you do. The least you can do is to give them flexibility in choosing their days off or ending the day early so that they can run errands, visit the bank or post office.
   
6. Treat yourself well and remember your loved ones . Take time off for yourself, plan a debriefing with friends or others in your laboratory halfway during your field season, and realize that your friends and family are more important than another sample point. I lost a boyfriend this way after I spent two summers away from him.
   
7. Prepare for the worst . I know this sounds pessimistic but I think it makes you prepared. Assume that everything is going to break, that it will rain … hell, that it will snow every day. That way your field season can only be better than expected.

Finally, get out there and enjoy yourself. If you aren’t enjoying what you are doing, why are you doing it?

Carmen Wong
Tree Ring Laboratory, Department of Geography
University of British Columbia
Vancouver, BC Canada
(604) 224-5292
E-mail: [email protected]

Since the Bulletin has gone electronic, the hope is that our journal will fill the niche between the science papers of Ecology and Ecological Applications and the science/policy of Frontiers in Ecology and the Environment.

One area that has been suggested by readers is essays on papers that particularly influenced the ideas and approaches to ecology of ecologists who have contributed to that particular subdiscipline of ecology. The idea is that the essay will both identify a paper or papers that were particularly important in catalyzing future developments, at least to the writer of the essay, and will also be a personal viewpoint. The working title for this section is: “The Paper Trail.”

The Paper Trail: W. S. Cooper’s “Fundamentals of Vegetational Change” and a Fluent Mode of Thought for Ecology

It is a bit amazing to admit that a paper that influenced me is now 80 years old! I encountered Cooper (1926) first in graduate school, but I have revisited it at intervals, and have been repeatedly stimulated and refreshed by it. In spite of the fact that I originally consulted this paper for its insights into plant succession, it is important not so much for what is says about succession, but for the analytical approach it takes. I believe the approach is one that can benefit ecologists in any specialty and at any age.

First a little background is in order. William Skinner Cooper, a professor of Botany at the University of Minnesota, was one of the most important of the first generation of American ecologists (McIntosh 1985). If, by chance, you are an American plant ecologist, you may well trace your lineage back to him (Sprugel 1980). He was the major professor of a number of active members of the second generation, who in turn trained many academic grand- and great-grandchildren. Henry J. Oosting, Murray F. Buell, and Rexford Daubenmire were especially prolific members of the second generation. This legacy is certainly a noteworthy role in the field. But when one looks at the big debate of the day—the nature of community dynamics—Cooper is conspicuous in not holding a dogmatic view about succession, or in unfailingly supporting either Clements or Gleason, whose differences have come to symbolize the debate. Instead, Cooper was guided by careful observation of communities in the field, and was remarkably free of ideology. The paper under consideration perhaps explains his open-mindedness and ability to see beyond ideology and ossified positions. Here is what “The fundamentals of vegetational change” (Cooper 1926) did for me. ¹

Cooper opens with a goal of examining and constructively criticizing the basics of his discipline: “A periodic inspection of foundations is most desirable for any edifice, and particularly so when the superstructure is being continually added to, as in the development of scientific knowledge.” (Cooper 1926:391). This is challenging stuff, because at that time it had been a mere 10 years since the publication of Clements’ (1916) big book on succession, with its proliferation of terminology, and exclusion of special cases, that promoted the questionable “organismal” concept of the plant community. Of course, the assumption that communities or ecosystems are equivalent to organisms in their development and stabilization has long since been rejected (Botkin and Sobel 1975). At the time, however, it was a persuasive and widely held idea. Cooper is telling us, whatever the orthodoxy, to go back to basics, and see what should stay and what should be rejected. This is the deepest lesson of his paper, which invites each generation of ecologists to reexamine the foundations of their discipline.

What should a rigid and dogmatic classification of succession, or for that matter, any ecological phenomenon, be replaced with? Oddly enough, although the study of succession and community change was called “dynamic ecology” at the time, Cooper noted that there was a proliferation of static classification systems of succession, each type having a narrow set of specific causes associated with it. He was concerned that the rigidity of classification systems would force ecologists to put actual communities in boxes that were not appropriate, and at any rate, that the classifications did not really account for change. He said, “It is our task to give verbal expression to constantly changing phenomena in a way that will parallel their mutations as closely as humanly possible.” (Cooper 1926:396). This was a call for flexible concepts and terms that reflected the flexibility—or perhaps in today’s terms, complexity—of the world to which the concepts referred. Such flexible terms would emerge from the actual process itself, rather than emerging from an idealization of it. This meant that “We must, accordingly, rigorously exclude all stock ecological terms and phrases, and treat the phenomena in a purely descriptive manner.” (Cooper 1926:396). So clear articulation of what the core phenomenon is, separate from the assumptions about it that yield idealized patterns or processes, becomes a key intellectual activity in ecology.

The specific features that Cooper identified as fundamental in succession are less important for the story I am telling than the approach he used. However, his summary of the fundamentals proved helpful to me in sorting through the problems of succession that were becoming clear in the 1970s, when I first encountered his paper (Box 1). For example, he took as fundamental that change in vegetation is universal, and included both contemporary and paleoecological changes. Change in vegetation could be due to any cause, not just ones that were expected to make succession move “forward.” Cooper, furthermore, included causes that arose from the characteristics and interactions of plants themselves, as well as those that were external to plants. Such things as soil differences in a biome, or fire, or people were all acceptable causes to Cooper, although Clements and his adherents viewed them as exceptions to be excluded from the study of succession. He took the interaction of plants and environmental causes (including animal activities) as a system. His recognition that different causes acted on various scales seems quite prescient of contemporary interest in scale. Cooper also indicated that all causes are always acting on vegetation change, though to different degrees. It was the complex interaction of a broad array of causes that resulted in vegetation change.

All of this was summarized in a powerful metaphor of vegetation change as a braided stream, with some channels moving swiftly and idiosyncratically, and some broad, conspicuous channels bringing smaller streams together, and moving slowly. Although the concept of climax, and of a successional “sere,” or series of repeatable stages, could be accommodated by such a metaphor, there was no compelling need for climax, or for a repeatable sequence of stages, or strict directionality of succession in such a world. Indeed, the fact of consistent instability in the vegetation of the past was a compelling reason to expect the universality of change in contemporary vegetation. One should look for changes on any time scale, and examine the complex causes that yielded a net effect of change. It was important to recognize how different causes might dominate in different situations, while seeing that the braided stream and its causes presented a “complex whole governed by groups of causes, all of which constantly influence its course.” (Cooper 1926:409).

This insight of Cooper’s concerning the broad applicability of causes, appears later in the idea that net effects in succession reflect an array of mechanisms. A hierarchical set of causes, which may act differentially at different periods of succession, is one way to apply Cooper’s insight (Pickett and Cadenasso 2005). Also important to me was the insight that “Destruction is inherent in all successions” (Cooper 1926: 404), which of course helped me recognize the broad role of natural disturbance in communities (Pickett and White 1985). This was not the only paper of Cooper’s to make that point.

Cooper’s concern with all causes and scales of vegetation dynamics was an important exemplar for me. He sought principles to explain all sorts of vegetation change, ranging from evolution on one extreme, through the grand shifts of paleoecology, to detailed contemporary community alteration. Therefore, his work suggested a broad and inclusive framework that could account for the evolutionary basis of succession (Pickett 1976), to the role of animals, herbivores, and predators (which had long been neglected by plant ecologists). The pursuit of broad, open-ended, and intentionally mutable frameworks has become one of the tasks I have set for myself, in part due to the insights offered by Cooper so long ago.

Cooper’s fluid thinking was easy for me to apply to vegetation dynamics, since that field initially stimulated his essay. However, his charge for each generation to examine the fundamentals of its concepts and frameworks echoes throughout ecology. Rigid classificatory systems of ecological phenomena, inappropriate reification of idealized concepts, and narrow conceptions of trajectories and causes, is not uncommon in ecology. Cooper’s exhortation for us all, whatever speciality we practice, to periodically examine our fundamentals, is as cogent today as when he put pen to paper over 80 years ago.

Just as the process is more than the product, so the mode of thought is more fundamental than the result thereof. Therefore, while believing thoroughly in the truth and usefulness of the ideas outlined in this paper, I am even more seriously interested in urging upon ecologists the fluent mode of thought which I have endeavored to exemplify in the formulation and presentation of these ideas. (Cooper 1926:411)

I hope that the emerging and tentative frameworks for vegetation change (Pickett and Cadenasso 2005), boundary dynamics (Cadenasso et al. 2003), landscape heterogeneity, and patch dynamics (Pickett et al. 2000), show the mark of Cooper’s influence, and at their best, rise to the level of fluid thinking for fluid phenomena. In any event, his call to reevaluate the fundamentals seems as relevant to all parts of ecology today as his original call that emerged from vegetation dynamics in 1926.

Literature cited

Botkin, D. B., and M. J. Sobel. 1975. Stability in time-varying ecosystems. American Naturalist 109:625–646.

Cadenasso M. L., S. T. A. Pickett, K. C. Weathers, and C. G. Jones. 2003. A framework for a theory of ecological boundaries. BioScience 53:750–758.

Clements, F. E. 1916. Plant succession: an analysis of the development of vegetation. Carnegie Institution of Washington, Washington, D.C., USA.

Cooper, W. S. 1926. The fundamentals of vegetational change. Ecology 7:391–413.

McIntosh, R. P. 1985. The background of ecology: concept and theory. Cambridge University Press, Cambridge, UK.

Pickett, S. T. A. 1976. Succession: an evolutionary interpretation. American Naturalist 110:107–119.

Pickett, S. T. A., and M. L. Cadenasso. 2005. Vegetation succession. Pages 172–198 in E. van der Maarel, editor. Vegetation ecology. Blackwell Publishing, Malden, Massachusetts, USA.

Pickett, S. T. A., M. L. Cadenasso, and C. G. Jones. 2000. Generation of heterogeneity by organisms: creation, maintenance, and transformation. Pages 33–52 in M. Hutchings, editor. Ecological consequences of habitat heterogeneity. Blackwell, New York, New York, USA.

Pickett, S. T. A., and P. S. White, editor. 1985. The ecology of natural disturbance and patch dynamics. Academic Press, Orlando, Florida, USA.

Sprugel, D. G. 1980. A “pedagogical genealogy” of American plant ecologists. ESA Bulletin 61:197–200.

Steward T. A. Pickett
Institute of Ecosystem Studies
Millbrook, NY 12545
E-mail: [email protected]

¹ Rereading Cooper’s paper in 2006 raises two questions about style. His use of “man” rather than “people” or “humans” is something that I find jarring. While I realize that grammarians may argue that is an acceptable use, I must warn contemporary readers that they may have to read beyond that usage. Cooper’s style is otherwise just a little more formal than today’s most formal writing. It is remarkably clear writing in spite of that formality.

Upstart Views of Restoration Icons

As ecological restoration efforts become better known and better studied, and as more ecologists choose to conduct research in restoration sites, the gap between applied science and theory becomes narrower. Such was the case when Margaret Palmer catalyzed a symposium for the 2002 ESA meeting in Tucson, where ecologists indicated how theory could inform restoration practice. Several speakers then expanded their remarks in a book (Falk et al. 2006) that further merged ecological theory and practice. Still, gaps will remain if the icons relied upon by restorationists are inconsistent with the latest advances in theory and understanding of how ecosystems develop. Accordingly, this symposium set out to deconstruct some icons of restoration ecology, by applying contemporary ecological theory to restoration ecology. The combined result represents a paradigm shift, away from equilibrial, predictable models and toward a world of restored ecosystems that is at least partly stochastic, time-varying, and context dependent.

One pervasive icon is a simple illustration of how ecosystem structure and function develop following some restoration effort (Fig. 1). A. D. Bradshaw (1984) depicted restoration as having a single target that is hit after substrates are modified, with ecosystem structure and function developing along the same linear pathway. His diagram continues to appear in books, papers, and even the journal Science (Dobson et al. 1997), although evidence supporting this model has never been included in those publications (Zedler and Lindig-Cisneros 2000). Our concern is not with Tony Bradshaw, who is himself an important icon of restoration ecology, for he was among the earliest ecologists to address actual restoration problems (how to vegetate mine tailings) and to urge others to recognize the value of studying restoration sites as a test of ecological understanding (e.g., Bradshaw 1987). Instead, the issue concerns those who expect restoration efforts to follow overly simple models, or who promise unrealistic pathways and outcomes.

Fig. 1. Simplification of Bradshaw’s (1984) model of restoration, showing a single target, a straight path, and a linear correlation between community structure and ecosystem function.

Because there is no complete guide to the theoretical foundations of restoration ecology, and because ecologists have much to offer in helping restoration ecology mature as a science (Zedler 2005), we convened a symposium on “Upstart Views of Restoration Icons” to highlight some of contributions of the new book (Falk et al. 2006), while asking authors and other speakers to stretch beyond previous writings to close further the gap between theory and practice. Dan Larkin solicited the speakers and organized the session; Joy Zedler moderated the symposium; and Don Falk provided the wrap-up. As a disclaimer, we did not ask speakers to critique the icon in Fig. 1; rather, we selected results from their talks that address this widely published model of how restoration works; thus, our descriptions of each presentation are not fully representative (in keeping with instructions for symposium commentaries in the ESA Bulletin).

Ten speakers (names in boldface type) provided evidence that dispels key elements of a key restoration icon (Fig. 1). Their presentations failed to support (1) a single obvious target for restoration, (2) a straight path to the target, and (3) a linear relationship between structure and function.

Upstart view No. 1. There is no single, obvious target for restoration; that is, reference conditions represent dynamic, multivariate, and nonequilibrial processes.

Bob Peet (University of North Carolina) presented a model of relationships between environmental conditions and plant communities that suggests appropriate species lists, proportions of plants/species, and sequences for introducing plants to individual restoration sites. Science-based “designer plantings” should reduce restoration efforts and costs. North Carolina’s Department of Transportation is using this approach to restore lands in anticipation of the need to mitigate impacts of future highway construction projects.

Roberto Lindig-Cisneros (University of Michoacana) added human needs to the list of constraints on the restoration target. In southern Mexico, managers agreed to allow experimental restoration of tephra (unvegetated ash that persisted 60 years following eruption of Mt. Paracutín), but only if the target could be the two native pine species that provide livelihoods (Fig. 2). In exchange, local people helped establish experimental plantings (with and without bark mulch). As expected, mulching lowered soil temperature and enhanced pine establishment, but, unexpectedly, the effect was strong only in dry years.

Fig. 2 . Forest-restoration experiment in Comunidad Indigena de Neuvo San Juan (Michoacán), where two species of native Pinus were planted with and without mulch (pine bark) in tephra (ash from the 1943–1952 eruption of Parcutín volcano) and with and without fencing to exclude herbivores. Photo by R. Lindig-Cisneros.

Denise Seliskar (University of Delaware-Lewis) demonstrated that tailoring could extend below the species level. After planting a salt marsh restoration site in Delaware (Fig. 3, photo) as an experiment to test the effects of three genotypes of Spartina alterniflora (from Maine, Delaware, and Georgia), she and others documented numerous impacts on everything from canopy height and stem density (Fig. 3, graphs), to root and rhizome distributions, edaphic chlorophyll concentration, and decomposition rates. Even the numbers of larval fish caught in pit traps differed by a factor of 2. She and Jack Gallagher then extended their research by selecting genotypes of many halophytes via tissue culture. Some genotypes are broadly tolerant of stressful field conditions, while others perform best in specific sites. “Designer genotypes” could increase survival and growth.

Fig. 3. Photo: Construction of a tidal wetland with creeks and a pool created near Lewes, Delaware, by excavating soil from abandoned agricultural upland. Three genotypes of Spartina alterniflora (from Massachusetts, Delaware, and Georgia) were planted on the marsh plain in order to study their effect on marsh function. Graphs: Among the responses were differences in canopy height and stem density of Spartina alterniflora at the site (pink bars); values at their site of origin are in yellow. See Seliskar et al. (2000).

Stuart Findlay (Institute for Ecosystem Studies, New York) gave compelling evidence that multiple-function ecosystems are unrealistic targets for wetlands. While we might aim for clean water, high productivity, high biodiversity, flood reduction, and other functions, he argued that restoration sites are context dependent and typically do not provide all the ecosystem services expected of them, and that some combinations of functions are mutually exclusive (Fig. 4). If multiple driving factors are not correlated in space or time, individual sites cannot excel in several functions simultaneously. This leads to high interannual variability in site performance and argues for a relaxation of the restoration target. Thus, plans to restore multiple functions in a watershed will require multiple restoration sites and efforts.

Fig. 4. Functions may also have complex controlling factors, as in this example, which illustrates that the capacity of a patch of submerged aquatic vegetation to ameliorate high turbidity conditions is spatially contingent. Patches within ~100 m of the 5-m depth contour have a much lower likelihood of maintaining turbidity below 40 NTU (neothelometric turbidity units). Using this water clarity criterion as a performance measure would require relaxing the criterion for sites closer to deep waters. Graph by S. Findlay.

As Don Falk concluded, the paradigm of the “single target” should shift to that of “reference dynamics” (Falk, in press), where interactions, temporal and spatial variability, and stochastic processes are emphasized. This makes defining the ecological reference more complex, difficult, and uncertain—but also more realistic.

Upstart view No. 2. Restoration does not always follow a straight path to the target; more realistically, restoration is never finished.

Katie Suding (University of California-Irvine) offered evidence that California grasslands resist restoration and follow an alternative states model (Fig. 5), with internal feedbacks that help sustain each of the dominance states, namely, the native bunch grass (which competes more strongly for N) and exotic annual grasses (which compete more strongly for light). Through innovative experimentation, she showed that soils formed under the native tended to favor the native, and that soils formed under exotics favored exotics. These and other results collectively support the alternative state model. Thus, if restorationists plant the “right” species in the “wrong” soil, the site will not necessarily favor the native vegetation.

Fig. 5. Predictions of alternative states that have direct applicability to restoration ecology: threshold patterns (at X 1 and X 2), regional coexistence (dominance of one state or dynamic regime below X 1 and one state above X 2), multiple attractors where either state could exist (solid lines between X 1 and X 2; the dotted line is a repellor), the presence of positive feedbacks (to drive the system to one or the other state), and hysteresis (recovery trajectory is different from collapse trajectory). All these predictions can be tested in a restoration context; several lines of evidence are needed. A system that demonstrates these dynamics requires a shift from single-equilibrium steady-state management to an adaptive approach that incorporates regional refugia, legacy, and priority effects, and resilience into its tool set. Graph courtesy of Suding.

Dan Larkin (University of Wisconsin) tested the importance of intertidal pools and tidal creeks to salt marsh food webs in a large experimental salt marsh (Fig. 6) and found increased feeding opportunities at high tide (more algal biomass, more invertebrates in pools) than where pools were lacking. Also, killifish fed more in areas with pools than without. Furthermore, tidal creeks enhanced use by mudsuckers. Thus, feeding opportunities were best restored where topography mimicked natural heterogeneity (creeks plus pools), but the relationships between species and microhabitat were complex.

Fig. 6. An 8-ha experimental marsh in the southwesternmost corner of California allowed comparison of areas with and without tidal creeks and with and without tidal pools. At high tide, killifishes preferentially occurred and fed in pools, where algal and invertebrate foods were most abundant. Fig. 6a shows a 1-ha “cell” with a creek branching off the tidal channel at the base of the photo; Fig. 6b shows tidal pools at the opposite side of the marsh and the dominant plant, Salicornia virginica. July 2005 photos by J. Zedler.

Holly Menninger (University of Maryland) culled the literature for examples of real evidence that substrate heterogeneity increases the diversity of taxa. In contrast to the above speakers, she found none for a dozen experiments in streams, including the work of her co-author, Margaret Palmer (Fig. 7). While the experiments being done in streams have not enhanced diversity of the taxa being explored, a focus on restoring processes in streams might help researchers figure out how to enrich diversity.

Fig. 7. Invertebrate taxa richness did not differ among heterogeneity treatments imposed by Brooks et al. (2002) in a Virginia stream. Treatments differed in the variability of streambed particle sizes in entire riffles.
Redrawn from Brooks et al. (2002).

As Don Falk summed it up, the emerging view of the postrestoration state is one of complex, and at least partly stochastic, spatially contingent systems, with nonlinear response functions to treatments, nondeterministic outcomes, and nonequilibrial properties.

Upstart view No. 3. Structure and function are not linearly related.

Shahid Naeem (Columbia University) indicated that many plant species combinations might be viable restoration targets, based on biodiversity–ecosystem function (BEF) theory, and that the relationship to species richness will differ by function. He unveiled a new 5-year experiment (Fig. 8) that is underway in Mongolia, involving >700 plots (each 6 × 6 m) that will have controlled composition and species richness for the first years, before opening plots to grazing and assessing their functional capacity (including livestock production). “Combinatorial forecasting” could lead to recommendations for specific richness levels and/or assemblages for use in restoring specific ecosystem functions.

Fig. 8. Ambitious new 5-year experiment to test Biodiversity Ecosystem Function (BEF) theory in grasslands of Inner Mongolia. Plots are 6 × 6 m; weeded by hand to control species richness. Photo by S. Naeem.

Greg Bruland (University of Hawaii) tested the ability to restore both species and functions to a former forested wetland that was farmed (and flattened in the process), and then regraded to create a large experiment in topographic heterogeneity (1.3-m vertical range). Aboveground biomass accumulated least on hummocks and most in hollows, while species richness increased from hummocks to hollows to flats (Fig. 9)—not a linear correlation between these measures of function and structure. Overall, the specialization of species to microhabitats led to high diversity at the site scale.

Fig. 9. Mean species richness (i) and aboveground biomass (ii) in three microtopographic treatments in a restored wetland. Data are means ± 1 SE; a,b,c differed using ANOVA. Redrawn from Bruland and Richardson (2005).

Joy Zedler (University of Wisconsin) filled a gap in the program with Suzanne Kercher and Andrea Herr-Turoff’s data from wet prairie mesocosms. As an invasive grass expanded, biomass increased and species richness decreased. Then, despite killing the grass with herbicide, biomass remained high where few species remained. Productivity and species richness were negatively related, contradicting the notion of a positive linear correlation; furthermore, restorability was lower where stormwater treatments (flooding and nutrients) were continued than where they ceased.

Clever theorists and talented experimentalists continue to amass impressive data sets that challenge traditional views that restoration outcomes are predictable (we achieve a specific target), defined (variation is around a predetermined mean condition), and stable (we can keep the system that way). We summarize with:

Upstart view No. 4: Restoration outcomes are unpredictable, stochastic, and nonequilibrial, and the work is never finished.

While the “Bradshaw icon” might characterize some components of some restoration projects at some times, a more dynamic paradigm for restored ecosystems would accommodate variability and even unpredictability as positive signs of healthy, functioning systems.

Literature cited

Bradshaw, A. D. 1984. Ecological principles and land reclamation practice. Landscape Planning 11:35–48.

Bradshaw, A. D. 1987. Restoration: an acid test for ecology. Pages 23–29 in W. R. Jordan III, M. E. Gilpin, and J. D. Aber. Restoration ecology: a synthetic approach to ecological research. Cambridge University Press, Cambridge, UK.

Brooks, S. S., M. A. Palmer, B. J. Cardinale, C. M. Swan, and S. Ribblett. 2002. Assessing stream ecosystem rehabilitation: limitations of community structure data. Restoration Ecology 10: 156–168.

Bruland, G. L., and C. J. Richardson. 2005. Hydrologic, edaphic, and vegetative responses to microtopographic reestablishment in a restored wetland. Restoration Ecology 13:515–523.

Dobson, A. P., A. D. Bradshaw and A. J. M. Baker. 1997. Hopes for the future: restoration ecology and conservation biology. Science 227:515–522.

Falk, D. A. In press. Process-centered restoration and reference dynamics. Journal of Nature Conservation.

Falk, D., M. Palmer, and J. B. Zedler, editors. Foundations of restoration ecology. Island Press, Washington, D.C., USA.

Seliskar, D. M, J. L. Gallagher, D. M. Burdick, and L. A. Mutz. 2002. The regulation of ecosystem functions by ecotypic variation in the dominant plant: a Spartina alterniflora salt-marsh case study. Journal of Ecology 90:1–11.

Zedler, J. B. 2005. Restoration ecology: Principles from field tests of theory. San Francisco Estuary and Watershed Science. ‹ http://repositories.cdlib.org/jmie/sfews/vol3/iss2/art4›

Zedler, J. B., and R. Lindig-Cisneros. 2001. Functional equivalency of restored and natural salt marshes. Pages 565–582 in M. Weinstein and D. Kreeger, editors. Concepts and controversies in tidal marsh ecology. Kluwer Academic, Dordrecht, The Netherlands.

Joy B. Zedler, Botany Department and Arboretum, University of Wisconsin-Madison, Madison, WI 53706, E-mail: [email protected]

Donald A. Falk, Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721

Daniel J. Larkin, Botany Department, University of Wisconsin-Madison, Madison, WI 53706

Urban Food Webs: Errata. Revised Text and Figures

Urban Food Webs: Errata. Revised Text and Figures

In the October 2006 issue of the ESA Bulletin, two errors appeared in the Symposium Review “Urban Food Webs” (pages 387–393). In the list of authors, Thomas Parker should have appeared as Tommy Parker. And in Fig. 3a (page 389), the scientific name should be spelled “Habrophlebiodes,” as shown in the corrected figure below.

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