Applications from food web and ecosystem theory - Ecological Applications: Toward a Sustainable World - page 263

Fig. 9.15 The economic
value of retaining or
converting natural
habitats expressed in
US$ per hectare, each
estimated over a 30- to
50-year period. In each
case, the less intensive
exploitation regimes are
shown as light
histograms and the
heaviest exploitation as
dark histograms. (a)
Tropical forest in
Malaysia; (b) tropical
forest in Cameroon; (c)
mangrove in Thailand;
(d) coral reef in the
Philippines; (e) wetland
in Canada. (After
Balmford et al., 2002.)

(a) (b)

15,000

3000
2000
1000

10,000
5000
0

0
-1000
-2000

Reduced-
impact
logging

Conventional
logging

Reduced-
impact
logging

Small-
scale
farming Plantation

(c) (d)

80,000

4000
3000
2000
1000
0

60,000
40,000
20,000
0

Intact Shrimp

farming

Sustainable
fishing

Destructive
fishing

(e)

10,000
8000
6000
4000
2000
0

Intact Intensive

farming

account the loss of ecosystem services from timber and nontimber products, char-
coal, offshore fi sheries and the storm protection associated with the intact ecosystem
(Figure 9.15c). And the picture is similar for coral reefs in the Philippines. Despite
high initial benefi ts from destructive fi shing (involving dynamite), the combined
benefi ts from sustainable fi shing and tourism, when added to the reef's ecosystem
service of coastal protection from storms, far outweigh any short-term gain (Figure
9.15d). Had there been more intact reefs around coasts hit by the 2004 Pacifi c-wide
tsunami, who can say how many lives and livelihoods would have been saved
(Section 9.1).
Finally, the draining of freshwater marshes for agriculture often produces private
benefi t (sometimes, as in this case, because of drainage subsidies provided by the
government). However, ecosystem services from intact wetland include recreational
opportunities (hunting, trapping and angling) and the uptake of nutrients as these
move from land to rivers and beyond; when the dollar values of these are taken into
account the overall economic value of intact wetland exceeds converted land by
about 60% (Figure 9.15e).
Most often a number of species contribute to each ecosystem service and it is
important to remember that some may make a more important contribution than
others, something that managers need to recognize when assessing threats. I
described earlier the contribution made to watermelon pollination by wild bees that