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Brad NelsonBIOL 7083
Community Ecology
Robert H. MacArthur:Life, Work, and Legacy
Biographical Sketch
Robert H. MacArthurApril 2, 1930 – November 1, 1972
Personal Background• Born in Toronto, Ontario• Youngest son of John Wood
MacArthur (geneticist)• Married Elizabeth
Whittemore (1952)• Had four children• Died of renal cancer at the
age of 42
Biographical Sketch
Robert H. MacArthurApril 2, 1930 – November 1, 1972
Academic Background• Undergraduate degree
from Marlboro College, 1951• M.S. in Mathematics
from Brown University, 1953• Ph.D. from Yale University, 1958
(under G. Evelyn Hutchinson)• Postdoc at Oxford University• Professor at University of
Pennsylvania (1958-1965)• Professor at Princeton
University (1965-1972)
MacArthur Publications
Pianka and Horn (2005)
MacArthur Publications
Pianka and Horn (2005)
MacArthur Publication Characteristics
• Hypothetico-Deductive (H-D) method
• Most ecological studies at the time were descriptive
MacArthur Publication Characteristics
• Use of simple analytical models to generate and test hypotheses
MacArthur Publication Characteristics
• Circumvented traditional peer review process
• Proceedings of the National Academy of Science
• Princeton Monograph Series
• Journal of Theoretical Population Biology
MacArthur Publication Characteristics
• “Weak” tests of hypotheses
• Observational, not experimental
• Theory of Island Biogeography– Not tested
experimentally until 1969
• Warbler paper (1958)
MacArthur Publication Characteristics
• Many published mistakes
• MacArthur and Levins’ limiting similarity paper (1967)
• Warbler paper (1958):
• Limited use of citations
MacArthur Publication Characteristics
MacArthur and Pianka 1966
Selected Publications
The Theory of Island Biogeography
• About 4,150 citations since 2000 (Google Scholar)
On Optimal Use of a Patchy Environment (MacArthur and Pianka 1966)
• Search time vs. pursuit time• Considers effects of patchy environment• Landmark paper in optimal foraging theory
and behavioral ecology• About 110 citations since 2000 (Google
Scholar)
On Optimal Use of a Patchy Environment (MacArthur and Pianka 1966)
• N = number of items in diet
• TN = Time per food item
• TNS = Search time per
food item• TN
P = Pursuit time per food item
• Food types ranked from most efficient to least (calories/time)
• What is the optimal number of items to include in the diet?
On Optimal Use of a Patchy Environment (MacArthur and Pianka 1966)
Search vs. Pursuit (Uniform prey item abundance)
Search vs. Pursuit (Non-uniform prey item abundance)
On Optimal Use of a Patchy Environment (MacArthur and Pianka 1966)
Hunting time vs. travelling timeIn a patchy environment
Patches ordered by prey density
(Number of patches utilized)
On Optimal Use of a Patchy Environment (MacArthur and Pianka 1966)
Population Ecology of Some Warblersof Northeastern Coniferous Forests
Population Ecology of Some Warblersof Northeastern Coniferous Forests
• Five congeneric species of warblers found together without obvious interspecific differences
• How do they coexist?
Population Ecology of Some Warblersof Northeastern Coniferous Forests
• MacArthur notes: “…differences … are neither always necessary nor always sufficient to prevent competition and permit coexistence”
• He then documents species differences and concludes that they permit coexistence
Population Ecology of Some Warblersof Northeastern Coniferous Forests
• Data– Local censuses• Staggered population changes
– Museum and diet records– Field observation• 27 to 90 minutes of continuous
observation
– Wintering grounds observation
Population Ecology of Some Warblersof Northeastern Coniferous Forests
• Warbler coexistence attributed to differences in foraging zone (MacArthur 1958)
• If competition limits diversity (limiting similarity), more species should exist in more complex habitats because more types of foraging sites are available, reducing competition (MacArthur 1958, 1972)
Population Ecology of Some Warblersof Northeastern Coniferous Forests
• Evidence of competition and food limitation indirect or absent
Martin 1993:
• Alternative: “Potential-prey-site hypothesis”
• Bird species nest preferentially in different foliage• Predators should search
foliage where abundant species nest
• Preferential nest predation allows persistence of rare species
Population Ecology of Some Warblersof Northeastern Coniferous Forests
Martin 1993
MacArthur’s Legacy
• Added open-mindedness to the list of traits desirable in a scientist (along with empiricism and skepticism) (Fretwell 1975)
• Popularized H-D method in ecology– In roughly 5% of Ecology papers before MacArthur
and 50% by 1975 (Fretwell)• Optimal foraging and island biogeography
theory continue to be fruitful avenues of research
MacArthur’s Legacy
• Many ecologists tried to adapt the style of his warbler paper, typically with less success (Fretwell 1975, Kaspari 2008)
• Differences between species continued to be used as explanation for coexistence despite the lack of quantitative testing
MacArthur’s Legacy
• Does MacArthur’s research style have a place in community ecology today?
• Still common in biogeography (Esselstein?), where patterns can be observed, but laboratory and field experiments are not often possible
“To spread, a scientific meme should be correct. But it has to be infectious.”
--Kaspari (2008)
ReferencesFretwell, S.D. The impact of Robert MacArthur on Ecology. Annu. Rev. Ecol. Syst.
1975.6: 1-13.Kaspari, M. 2008. Knowing your warblers: thoughts on the 50th anniversary of
MacArthur (1958). Bulletin of the Ecological Society of America.MacArthur, R. H. 1958. Population ecology of some warblers of Northeastern
coniferous forests. Ecology 39: 599-619.MacArthur, R.H. and E.R. Pianka. 1966. On optimal use of a patchy environment.
The American Naturalist 100(916): 603-609.MacArthur, R.H. and E.O. Wilson. 1967. The theory of island biogeography.
Princeton University Press. 205 pp.Martin, T.E. 1993. Nest predation and nest sites: new perspectives on old
patterns. Bioscience 43(8): 523-532.Pianka, E. R. and H. S. Horn. 2005. Ecology's Legacy from Robert MacArthur.
Chapter 11 (pp. 213-232) in K. Cuddington and B. Biesner, eds. "Ecological Paradigms Lost: Theory Change." Academic Press.
Wilson, E.O. and G.E. Hutchinson. 1989. Robert Helmer MacArthur. Biographical Memoirs 58: 318-327.
Questions?