Dealing with global climate change - Ecological Applications: Toward a Sustainable World - page 318

Table 11.1 Average equilibrium ecological effects on forestry of a global climate change model
assuming a doubling of atmospheric CO 2 . North America has the smallest predicted increase in
forest productivity (cubic meters of wood per hectare per year) and, with Russia and China, a
particularly large increase in the percentage of forest lost (dieback) because of fi res, storms and
pests. South America and China have the biggest predicted increases in forest habitable area
under the climate change scenario. (From Sohngen & Sedjo, 2005.)

% Increase in % Increase in

forest productivity % Dieback forest area

North America 17 28 4

South America 23 10 27

Europe 34 9 7

Russia 52 21 14

China 38 20 20

11.4 Climate change
predictions based on
community and
ecosystem
interactions

Chapters 8 and 9 dealt with lessons for managers from the theories associated with
community and ecosystem functioning. Global climate change can be expected to
wreak effects on patterns of community succession (Section 11.4.1), via the com-
plexities of food-web interactions (Section 11.4.2) and to alter the range and type of
ecosystem services provided free to human society (Section 11.4.3).

11.4.1 Succession -
new trajectories and
end points

You saw in Chapter 8 how community composition is affected by disturbances,
whether these are natural (such as hurricanes or volcanic eruptions) or manmade
(such as forest clearing / burning for agriculture). The resulting community succes-
sions have characteristic trajectories and end points that are governed by local soils,
topography and climate. Climate change, fi rst, has the power to change disturbance
frequency - by altering storm patterns and fi res. Second, it can modify the interac-
tions among species, particularly competition and facilitation (Box 8.1), which so
infl uence the course of succession. And, third, as we have already seen, climate
change is predicted to affect successional end points or, in other words, the charac-
teristic biome of the area in question (Figure 11.3). Moreover, if species' ranges shift
at different rates, then species' richness may also be affected, if only transiently. For

Fig. 11.11 Projected
percentage increases in
annual forestry harvest
(in cubic meters per
year), averaged for two
climate change models
that involve a doubling
of atmospheric CO 2 .
The contrasting
regional patterns refl ect
predicted differences in
growth rate increase,
dieback (due to storm,
fi re and pests) and
changes to total tree
habitable area. The
models include the
assumption that
foresters will adapt to
climate change by
planting more
appropriate trees.
(From Sohngen &
Sedjo, 2005.)

70

North America
South America
Europe
Russia
China

60

50

40

30

20

10

0

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