|SREL Reprint #1838|
Tropical Mass Extinctions and the Scientific Method
John B. Dunning Jr.
Institute of Ecology, University of Georgia, Athens, GA 30602
Kangas (1992) argues that there is a paradox concerning the mass extinctions projected from current rates of tropical deforestation. He states that there is wide acknowledgment that the vast majority of species in the tropics are undescribed, thus the projected mass extinction will be dominated by the loss of unknown species. Kangas proposes, however, that this generates an unfaisifiable hypothesis: because we cannot prove the extinction of species that we do not know to exist, we cannot study the extinctions that we know to be occurring. Kangas concludes that the tropical mass extinction "will be a terrible loss," but it will be a loss that we cannot use the scientific method to study.
Kangas would be right if the extinction process can be studied only by
specifically identifying each threatened species and then documenting its
extinction. In fact, we do not need to know the identities of the threatened
species. Instead, we can study the extinction process if we know the expected
number of undescribed species that would go extinct with the loss of a particular
area of tropical forest. If we knew the mean and variance of the expected
number of undescribed species in 100 ha of tropical forest, for instance, then we
could generate predictions as to how many undescribed species might be
destroyed by the loss of specific tracts of forest. These predictions then could be
tested as falsifiable hypotheses on the extent of extinction in a particular region.
SREL Reprint #1838
Dunning, J.B., Jr. 1994. Tropical mass extinctions and the scientific method. Bulletin of the Ecological Society of America 75:44-45.