0198566123.pdf

140 °E

120 °E

100 °E

80 °E

60 °E

40 °E20°E20°W40°W

60 °W

80 °W

100 °

W

120 °W

Days elapsed

from time of

launch

5

100

90

40 30 75

50

15

20

65

80

95

35

55

45

35

25

10

70

60

0

5

102

0 °

160 °E 180 ° 160 °W

Figure 3.8Floristic affinities of Gough Island (Tristan da Cunha) in relation to predominant wind direction as revealed by the flight of a
balloon: areas sharing 20–25 species, cross hatch; 15–20 species, single hatching; 10–15 species, heavy stipple; 5–10 species, light stipple.
(After Moore 1979, Figs 1 and 2.)

yet essentially oceanic in character for organisms

with poor powers of dispersal through or across

seas (e.g. conifers, terrestrial mammals, and

freshwater fish). Moreover, there are some groups

of islands of mixed origins and types, e.g. the

Seychelles, or which appear to have been

partially connected at times of lowered sea

levels, such that they have biological

characteristics part way between oceanic

and continental, land-bridge islands (as

discussed for the avifauna of the Philippines

by Diamond and Gilpin, 1983).

58 THE BIOGEOGRAPHY OF ISLAND LIFE