Distance to Mainland and Nearest 
Larger island, 
I calculated distance to mainland 
and distance to the nearest larger 
island for each of the 423 islands in 
the study using the measuring tool in 
GAIA. This tool returns the number 
of pixels between two user-defined 
points. I then converted those values 
into kilometers to produce a measure 
of an island’s isolation. 
Diversity versus Biodiversity. 
According to the equilibrium theory 
of island biogeography (MacArthur 
and Wilson 1967) all things being 
equal larger islands and islands with 
long shorelines should equilibrate 
with greater numbers of plant and 
animal species than small islands 
with less shoreline. Also, islands 
with relatively high habitat diversity 
should support greater numbers of 
birds, mammals and other 
vertebrates. To test this I compared 
the richness of mammals among 18 
islands (Crowell 1986) that varied 
with regards to size, habitat diversity, 
isolation and shoreline. 
RESULTS AND DISCUSSION 
Table one lists the variables that are surveyed, are the 18 islands for 
readily extractable from satellite which mammal richness data is 
imagery using GAIA software. These available, 
islands, a subset of the 423 islands I 
Table 1. Example of data retrieved from SPOT MS imagery in conjunction with 
GAIA and Image software packages. (Mammal data from Crowell 1986) 
NAME 
P (km) 
C 
A(km A 2) 
s 
H 
Hmax 
Dm(km) 
Di(km) 
MAM. (spp.) 
Potato 
0.49 
1.19 
0.01 
14 
2.34 
2.64 
14.08 
0.24 
1.3 
Mark 
0.72 
1.14 
0.03 
25 
2.77 
3.22 
16.99 
1.04 
2.1 
Scraggy 
1.22 
1.79 
0.04 
21 
2.42 
3.04 
17.99 
1.46 
2.0 
Farrell 
1.41 
1.46 
0.07 
31 
2.80 
3.43 
16.60 
1.44 
2.0 
Rock 
0.52 
1.20 
0.02 
18 
2.60 
2.89 
15.95 
0.40 
2.0 
Matinicus 
11.02 
1.71 
3.29 
52 
3.72 
3.95 
23.80 
18.24 
2.0 
Camp 
2.78 
1.48 
0.28 
43 
3.20 
3.76 
11.41 
1.09 
2.5 
Eagle 
6.36 
1.59 
1.27 
51 
3.68 
3.93 
10.11 
2.89 
3.0 
Hardwood 
0.93 
1.10 
0.06 
31 
. 3.06 
3.43 
16.91 
0.51 
3.0 
Crotch 
6.40 
1.99 
0.83 
51 
3.55 
3.93 
14.08 
0.34 
3.5 
Merchants 
6.93 
1.93 
1.03 
50 
3.29 
3.91 
16.29 
1.55 
4.5 
Kimball 
9.45 
1.91 
1.95 
51 
3.25 
3.93 
18.39 
0.19 
7.0 
Isle-Au-Haut 
45.19 
2.44 
27.23 
51 
3.35 
3.93 
16.83 
10.11 
10.0 
Hog 
6.95 
1.76 
1.24 
42 
2.78 
3.74 
0.25 
0.67 
10.0 
Islesboro 
75.70 
3.91 
29.83 
52 
3.50 
3.95 
2.50 
12.09 
10.0 
Vinalhaven 
138.43 
5.24 
55.46 
53 
3.69 
3.97 
10.60 
9.50 
11.0 
Deer Isle 
139.08 
4.51 
75.67 
52 
3.71 
3.95 
1.76 
14.65 
17.0 
Second 
0.54 
1.15 
0.02 
17 
2.26 
2.83 
16.56 
0.61 
1.5 
P = perimeter; C = index of convolutedness; A= area; s = habitat richness; H = habitat diversity; 
Dm = distance to mainland; and Di = distance to nearest larger island. 
Landscape diversity is positively 
correlated to island area (Figure 2.). 
This is consistent with the 
equilibrium theory of island 
biogeography (MacArthur and 
Wilson 1967) which reasons that 
larger islands have a greater 
likelihood of supporting a diverse 
array of habitats. Yet there are 
islands that are an exception to this 
pattern, that is, relatively large 
islands with low diversity. These 
“outliers” (set off by a box in Figure2.) 
turn out to be isolated outer islands 
exposed to environmental 
Log(10) Area (km A 2) 
Fig. 2. The relationship between landscape 
diversity and island area tor 423 islands in 
Penobscot Bay, Maine (the box indicates 
outliers discussed in text). 
45