title: On the regulation of populations of mammals, birds, fish, and insects.
abstract: A key unresolved question in population ecology concerns the relationship between a population's size and its growth rate. We estimated this relationship for 1780 time series of mammals, birds, fish, and insects. We found that rates of population growth are high at low population densities but, contrary to previous predictions, decline rapidly with increasing population size and then flatten out, for all four taxa. This produces a strongly concave relationship between a population's growth rate and its size. These findings have fundamental implications for our understanding of animals' lives, suggesting in particular that many animals in these taxa will be found living at densities above the carrying capacity of their environments.
authors.affiliation: School of Animal and Microbial Sciences, University of Reading, Whiteknights, Reading RG6 6AJ, UK. r.m.sibly@reading.ac.uk
authors.forename: Richard M
authors.initials: RM
authors.lastname: Sibly
authors.forename: Daniel
authors.initials: D
authors.lastname: Barker
authors.forename: Michael C
authors.initials: MC
authors.lastname: Denham
authors.forename: Jim
authors.initials: J
authors.lastname: Hone
authors.forename: Mark
authors.initials: M
authors.lastname: Pagel
mesh_terms: D000818:Animals; D000835:Animals, Wild; D001717:Birds; D003247:Conservation of Natural Resources; D016208:Databases, Factual; D017753:Ecosystem; D004777:Environment; D005399:Fishes; D007313:Insecta; D016015:Logistic Models; D008322:Mammals; D008433:Mathematics; D008954:Models, Biological; D010802:Phylogeny; D011156:Population Density; D011157:Population Dynamics; D011158:Population Growth; D012044:Regression Analysis