The SLOSS Debate was a debate in ecology and conservation biology during the 1970s and 1980s as to whether a Single Large or Several Small (SLOSS) reserves was a superior means of conserving biodiversity in a fragmented habitat.

In 1975 Jared Diamond suggested some "rules" for the design of protected areas, based on Robert MacArthur and E. O. Wilson's Theory of Island Biogeography. One of his suggestions was that a single large reserve was preferable to several smaller reserves whose total area was the same as that of the single large reserve. Since species richness increases with habitat area, a larger block of habitat would support more species than any of the smaller blocks. This idea was popularised by many other ecologists, and has been incorporated into most standard textbooks in conservation biology, and was used in real-world conservation planning. This idea was challenged by Wilson's former student Daniel Simberloff who pointed out that this idea relied on the assumption that smaller reserves had a nested species composition - it assumed that each larger reserve had all the species presented in any smaller reserve. If the smaller reserves had unshared species, then it was possible that two smaller reserves could have more species than a single large reserve. Debate ensured as to the extent to which smaller reserves shared species with one another, leading to the development of nested subset theory by Bruce Patterson and Wirt Atmar in the 1980s and to the establishment of the Biological Dynamics of Forest Fragments Project (BDFFP) near Manaus, Brazil in 1980 by Thomas Lovejoy.

See also

• Island biogeography

References

• Atmar, W. and B.D. Patterson. 1993. "The measure of order and disorder in the distribution of species in fragmented habitat." Oecologia 96:373-382.
• Diamond, J.M. 1975. "The Island Dilemma: Lessons of Modern Biogeographic Studies for the Design of Natural Reserves". Biological Conservation '''Vol. 7
• MacArthur, R. H. and Wilson, E. O. 1967. The Theory of Island Biogeography Princeton University Press.
• Patterson, B.D. and W. Atmar. 1986. "Nested subsets and the structure of insular mammalian faunas and archipelagos." In: Heaney L.R. and Patterson B.D. (eds), Island biogeography of mammals. Academic Press, London, pp 65-82.
• Simberloff, D. S. and L. G. Abele. 1976. Island biogeography theory and conservation practice. Science 191: 285-286
• Simberloff, D. S. and L. G. Abele. 1982. Refuge design and island biogeograpic theory - effects of fragmentation. American Naturalist 120:41-56
• Wilcox, B. A., and D. D. Murphy. 1985. Conservation strategy - effects of fragmentation on extinction. American Naturalist 125:879-887