Errata

p. 285, Results, Population growth, line 21 (Fig. 1A, 2B) should read (Fig. 1A, 2A) p. 288, 290, Figures 5 and 6 The illustration labelled "Fig 5" is the illustration for Fig6 and vice-versa. p. 289, line 35 "unpublished" should read "published".