The impact onecosystems 171Figure 7.11Vegetation maps of the south-eastern United States during past
climate regimes: (a) for 18 000 years ago at the maximum extent of the last ice
age, (b) for 10 000 years ago, (c) for 5000 years ago when conditions were
similar to present. A vegetation map for 200 years ago is similar to that in (c).