Ecological Archives E088-101-A3

Darren W. Johnson. 2007. Habitat complexity modifies post-settlement mortality and recruitment dynamics of a marine fish. Ecology 88:1716–1725.

Appendix C. Limitation functions for density-independent mortality, density-dependent mortality, and supply of recruits.

TABLE C1. Limitation functions for density-independent mortality, density-dependent mortality, and supply of recruits. Equations are derived from the Ricker model describing the relationship between recruits and 1-yr old blue rockfish: Nt = N0e(-α - βNo), where Nt = 1-yr old density, α = density-independent mortality, β = density-dependent mortality, N0= density of recruits, and k = level of perturbation (e.g., 1.1 for a 10% increase).  Nt (obs)= density of 1-yr olds predicted by the recruitment function when all processes are operating at ambient levels.

Source

Limitation function

Density-independent mortality

Nt = abs[Noe(-kα-βNo) - Nt(obs)]

Density-Dependent mortality

Nt = abs[Noe(-α-kβNo) - Nt(obs)]

Recruitment

Nt = abs[kNoe(-α-kβNo) - Nt(obs)]



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