Community Ecology



Community Ecology

History of community ecology

 

Outline:

1. History of community ecology from pre-1700s to today

    A. pre-1700s: an unordered and mystical world

    B. 18th century: descriptive (natural history) studies

    C. 19th century: "ecology" coined, Darwinism

    D. late 19th/early 20th centuries: self-awareness of ecology, "community" coined

    E. 20th century: Clements/Gleason succession debate, emphasis on quantification and comparison to null model

2. Early emphasis was on pattern; more recent research has explored process

Terms/people:

Haeckel    von Humboldt      Clements        MacArthur

Darwin           Forbes                       Gleason               Hutchinson

Möbius           Cowles                       Elton                   Shelford

Buffon             superorganism             individualistic      oikos

Linnaeus Whittaker Lack

 

Ecology has proceeded rather like a relay race, with each “leg” of the race differing from others in terms of pace, trajectory, and influence.  The first major leg of ecology came from the age of exploration, with repeated patterns of species co-occurrences being noted.  The second leg of ecology’s history is from late 19th-century/early 20th-century physiologists who tried to determine form as a consequence of environment.  The third leg came from an emphasis on biotic interactions (especially competition).  The fourth leg witnessed a greater emphasis on discerning process and not merely documenting pattern, comparing patterns with null models, and being skeptical of competition as the main driving force behind communities.  Some may argue that we are now in the fifth leg, focusing on the importance of taking scale into account, applying community ecology to conservation, and coping with a rapidly changing world.  

 

pre 18th century:

-biology largely unordered (pre-Linnaeus)

-world still highly mystical

 

18th century:

-natural history - descriptive

-order/progress (influenced by the Church)

-equilibrium/”balance of nature”

-Carolus Linnaeus - orderly scientific nomenclature (hierarchical)

-Georges-Louis Leclerc, Comte de Buffon - naturalist, first described how environment shapes animals

19th century:  

-Alexander von Humboldt 1807 -

-1859: Charles Darwin’s Origin of Species: scientific revolution from natural selection

-Ernst Haeckel 1866 -

 

late 19th/early 20th centuries:

-crystallization of ecology, self-awareness of ecology

-Karl Möbius 1877 (translated in 1883) -

-Stephen A. Forbes 1887 -

-Henry Chandler Cowles 1899 - U. Chicago, succession, stability; studies changes in plant community on the sand dunes of Lake Michigan between 1898 and 1911. Emphasis on the dynamic nature of vegetation.

 

20th century:

-Victor Shelford 1915 - U. Nebraska, first president of ESA (founded 1915); looked at animal communities in the same manner that plant ecologists did

-Frederic Clements 1916, 1936 - U. Nebraska, one of the most influential ecologists

"superorganism" -

-Henry Gleason 1917, 1926 - IL Nat. Survey

    Individualistic view of community structure -

-Clements vs. Gleason debate of whether a community is a definable unit vs. a level of organization above that of populations in a given area: are communities simply equal to the sum of their parts, or do special properties emerge that define and control the community’s existence?

2 views of communities: the question is whether a community is a definable unit vs. a level of organization above that of populations in a given area

1) individualistic hypothesis - chance occurrence of species with similar habitat requirements, due to environmental filtering that results in an assemblage of species with traits that allow them to persist in a given area

2) superorganism concept - all species are closely tied together and locked into associations, species that make up the community function together as a unit, dependent on each other

C. vs. G. boiled down to whether communities were deterministic and discrete entities (C.) or stochastic and continuous (no clear boundaries, community change difficult to see; G.). Put another way, the difference between the two men’s views is whether communities are “open” or “closed”: a closed (Clementsian) community is a stable combination of species drawn from a regional species pool, and complementary sets of species in closed communities tend to replace each other at the same point along environmental gradients. Competition for limited resources can structure local compositions of species. An open (Gleasonian) community, on the other hand, is a fortuitous and dynamic assemblage of mostly noninteracting species. The species in open communities each align themselves independently along environmental gradients according to their own ecological requirements.

-Robert Whittaker’s gradient analyses helped resolve the C. vs. G. debate

-Charles Elton 1927 - animal ecologist, niche, food webs; book Animal Ecology (1927) written in a mere 85 days and is still in print

-David Lack 1940s – role of interspecific competition in shaping community structure

-1940-78 - G. Evelyn Hutchinson - limnologist and zoologist; niche; Ph.D. advisor for Robert MacArthur

-1950s-1960s - Odum brothers (Howard Tom and Eugene P.) - begin ecosystem studies, synthesize relatively new ideas on ecosystem ecology

-Robert H. MacArthur 1950s-60s - Hutchinson’s student; birds, very thoughtful and creative ecologist who tragically died young (in 1972 at age 42) but who formulated/influenced current thinking on competition, niche and habitat partitioning, biodiversity, food webs, extinction, importance of evolutionary life history traits, conservation biology and reserve design, and other topics; most influential ecologist in modern history

-1960s-1980s - increased emphasis on the need to describe community structure quantitatively (and against a null model)

1990s-2000s - development of multivariate statistical methods (and computer programs) needed to quantify community structure

-influence of non-English-speakers (e.g. Vasily Dokuchaev)

Early CE was devoted to noting which species were found in a particular area (pattern description); the question of why these species occurred but not others in a given area (process) was not addressed until later (1950s +). As with most disciplines, pattern description came before process explanations.

Current approaches in community ecology:

 

There have been various attempts to define the most important concepts or central themes of ecology. Here are what I believe to be the three central themes of contemporary community ecology:

1. Ecological systems are variable in space and time (cf. the equilibrium/homogeneity paradigm).

2. Ecological patterns and processes are scale-dependent (cf. scale is irrelevant or too messy).

3. Ecological systems are open to external influences (cf. the closed-system paradigm).

One key point: in studying communities, we must be able to distinguish pattern from “noise.” So next time: ecology as a science, the scientific method, hypothesis-testing.

References:

 

Gleason, H.A. 1926. The individualistic concept of the plant association. Bull. Torrey Bot. Club 53:7-26.

Golley, F.B. 1993. A History of the Ecosystem Concept in Ecology. Yale University Press, New Haven, CT.

 

Hagen, J.B. 1989. Research perspectives and the anomalous status of modern ecology. Biology and Philosophy 4:433-455.

 

Hagen, J.B. 1992. An Entangled Bank: The Origins of Ecosystem Ecology. Rutgers University Press, New Brunswick, NJ.

 

Kingsland, S.E. 1985. Modeling Nature: Episodes in the History of Population Ecology. University of Chicago Press, Chicago, IL.

McIntosh, R.P. 1985. The Background of Ecology. Cambridge University Press, Cambridge, UK.

 

McIntosh, R.P. 1995. H.A. Gleason’s ‘individualistic concept’ and theory of animal communities: a continuing controversy. Biological Reviews 70:317-357.

 

Odum, E.P. 1977. The emergence of ecology as a new integrative discipline. Science 195:1289-1293.

 

Sheail, J. 1987. Seventy-five Years in Ecology: The British Ecological Society. Blackwell Scientific Publications, Oxford, UK.

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