Dealing with global climate change - Ecological Applications: Toward a Sustainable World - page 321

Fig. 11.13 Stress status
of river catchment areas
throughout Europe by
2080 according to four
different climate change
models. In a few areas,
water stress is reduced
in comparison to no
climate change (blue),
in many places there is
no change (yellow), but
in some areas water
stress is set to increase
(orange, red). (From
Schroter et al., 2005.)
(This fi gure also
reproduced as color
plate 11.13.)

Scenario 1 Scenario 2

Scenario 3 Scenario 4

Change in water stress status

moved out of stressed class
reduction in stress
basin never stressed
no significant change
increase in stress
moved into stressed class

of Protea species may be at risk of extinction due to climate change (Thomas et al.,
2004). And this conclusion is based on the optimistic assumption that all Protea
species are capable of dispersing to all currently uninhabited areas that become
inhabitable. If no dispersal is assumed, and future ranges are simply those reduced
parts of current ranges that remain inhabitable, 30-40% of species seem at risk of
extinction. Similar fates could await diverse animal and plant taxa around the world.
In many cases, though, suitable choice of protected areas can minimize the predicted
losses (Sections 11.5.1, 11.5.2).

11.5.1 Mexican cacti
- reserves in the
wrong place

Climate change poses a real conundrum for biodiversity managers. Will current
nature reserves, designed to protect particular elements of biodiversity, turn out to
be in the wrong places? Cacti are the dominant plant form in Mexico's Tehuacán-
Cuicatlán Biosphere Reserve. From knowledge of the biophysical basis of current
distributions and assuming one of three future climate scenarios, Téllez-Valdés and