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RESPONSE OF COMPLEX FOOD WEBS TO REALISTIC EXTINCTION SEQUENCES
Author(s) -
Srinivasan U. Thara,
Dunne Jennifer A.,
Harte John,
Martinez Neo D.
Publication year - 2007
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/06-0971
Subject(s) - extinction (optical mineralogy) , biodiversity , trophic level , ecology , ecosystem , extinction debt , biology , pelagic zone , extinction event , global biodiversity , habitat destruction , population , paleontology , biological dispersal , demography , sociology
Although an ecosystem's response to biodiversity loss depends on the order in which species are lost, the extinction sequences generally used to explore such responses in food webs have been ecologically unrealistic. We investigate how several extinction orders affect the minimum number of secondary extinctions expected within pelagic food webs from 34 temperate freshwater lakes. An ecologically plausible extinction order is derived from the geographically nested pattern of species composition among the lakes and is corroborated by species' pH tolerances. Simulations suggest that lake communities are remarkably robust to this realistic extinction order and highly sensitive to the reverse sequence of species loss. This sensitivity is not well explained by the known sensitivity of networks to the loss of highly connected species but appears to be better explained by our observation that trophic specialists preferentially consume widely distributed species at low risk of extinction. Our results highlight an important aspect of community organization that may help to maintain biodiversity amidst changing environments.