Regulation of Diversity: Maintenance of Species Richness in Changing Environments

• Published in: Oecologia Vol. 126; no. 3; pp. 321 - 332
• Main Authors: Brown, James H., S. K. Morgan Ernest, Parody, Jennifer M., Haskell, John P.
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 01.02.2001; Springer
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Biological taxonomies; Birds; Ecosystems; Extinct species; Fundamental and applied biological sciences. Psychology; Population ecology; Reviews; Rodents; Species; Species diversity; Species extinction; Synecology; Terrestrial ecosystems; United States; North America; Europe; Arizona; America; Michigan; Modification; Stability; Population extinction; Plant community; Rodentia; Species diversity; Vertebrata; Regulation(control); Mammalia; Animal community; Habitat; Pollen; Spermatophyta; Desert; Aves; Colonization; Species richness; Birds; Regulation; Ecosystem processes; Plants; Mammals
• ISSN: 0029-8549; 1432-1939
• DOI: 10.1007/s004420000536

In order to assess how diversity changes over time at sites undergoing environmental change, we examined three data sets on long-term trends in taxonomic richness and composition: (1) 22 years of rodent censuses from a site in the Chihuahuan Desert of Arizona; (2) 50 years of bird surveys from a three-county region of northern Michigan; and (3) approximately 10,000 years of pollen records from two sites in Europe. In all three cases, richness has remained remarkably constant despite large changes in composition. The results suggest that while species composition may be highly variable and change substantially in response to environmental change, species diversity is an emergent property of ecosystems that is often maintained within narrow limits. Such regulation of diversity requires maintenance of relatively constant levels of productivity and resource availability and an open system with opportunity for compensatory colonizations and extinctions. In addition to studying the effects of diversity on biogeochemical processes, it will often be useful to think of species richness as an emergent consequence of ecosystem processes.