Figure 3

Negative binomial regression models for functional groups showing significant association between mean seed density (no. m^™2) and time-since-fire for seed bank soil samples taken from Archbold Biological Station in January and July 1992, August 2008, and January 2009. (a) Ruderal herbs, quadratic model (ratio of residual deviance over degrees of freedom = 1.4; P = 3.2e^™8; w _i = 0.69). (b) Subshrubs, quadratic model (ratio = 1.7; P = 0.005; w _i = 0.44). (c) Scrub herbs, cubic model (ratio = 1.6, not selected as the best model; P = 0.008; w _i = 0.07). Analyses were conducted using centered time-since-fire values but graphed using original values.