Biology Reference
In-Depth Information
Fig. 2.17
Cumulative growth in reptile and amphibian introductions via the cargo pathway,
1850-1999. Blue line = data for cargo introductions; red line = best-fitting exponential equation
for those data, modelled by the function y = 6.0163e
0.2215x
, with R
2
= 0.9301
Fig. 2.18
Cumulative growth in reptile and amphibian introductions via the cargo pathway,
1890-1999. Blue line = data for cargo introductions; red line = best-fitting exponential equation
for those data, modelled by the function y = 10.991e
0.2943x
, with R
2
= 0.9888
(0.1766 and 39.1 years, respectively, for that same period). This accounts for the
late 20th century primacy of cargo-mediated over “intentional” introductions.
Another way to more simply summarize recent changes in pathway importance
is provided by looking at how the numbers of introductions/year have changed in
