Mediterranean Ecosystems Worldwide: Climate Adaptation - Recent Advances and Issues in Environmental Science - page 41

plant species in all mediterranean regions, except perhaps Chile, are well adapted to
natural fi re regimes, but a hotter and drier climate has been observed to promote [31]
and is projected to promote signifi cant alterations to the fi re regime beyond those
created by decades of human fi re management [28, 32, 33]. While rising atmospheric
CO 2 levels could provide benefi ts to mediterranean plant species [34], the effects are
altered when multiple factors of change are considered, including fi re, drought, tem-
perature increase, nitrogen deposition, and invasive species [35-38]. The rich plant
diversity of mediterranean systems is explained in part by the plant adaptations to
survive in low nutrient soils, such as California's serpentine soils, Australia's kwon-
gan, and South Africa's fynbos [3, 4, 9]. The patchy nature of soils will act as a barrier
and will make species migration in response to a changing climate more diffi cult. The
intrinsic adaptation potential of some mediterranean endemics, particularly in South
Africa and Australia, is limited by the relatively short seed dispersal distances and lack
of colonization ability of these plants [11, 29, 39, 40]. While these indirect and inter-
acting impacts of climate change are not explicitly considered in this analysis, they are
likely to further limit the adaptation potential of mediterranean species.
Despite the signifi cant projected contractions in the MCE, this analysis does of-
fer some reasons for hope and some guidance to direct future conservation action.
Approximately 50% of the biome is projected to remain stable with confi dence, even
under the high emissions scenario. Establishment and management of protected areas
in these areas in all fi ve regions represent sound investments given our current under-
standing of future change, and will help to secure future refugia for endemic species
from other threats such as land conversion. However, given the uncertainties associ-
ated with the indirect effects of climate change, a conservative conservation approach
should also include gene banking and ex-situ conservation for the rich fl oras of highly
threatened regions like Israel, Morocco, South Africa, and Australia.
Since this analysis was conducted using a consistent methodology across all fi ve
regions, we can use the results to determine the highest priority regions for action. As
shown in Figure 3, South Africa and Australia have the large projected contractions in
the MCE. The existing protected area network covers almost 7% of the current MCE
in these two regions. In South Africa, the protected areas are concentrated in the higher
elevations where the MCE is projected to remain stable, so 77% of the current pro-
tected areas are projected to retain mediterranean climate and only 3% are projected to
have a different climate in the future with high confi dence, even under the high emis-
sions scenario. In contrast, the protected areas in southwest Australia are concentrated
in the drier inland portions of the MCE, so only 10% of the current protected areas
will remain stable while 17% will likely shift to a new climate. These results suggest
that some of the fi rst strategies to enhance the extrinsic adaptation potential and to
reduce the threat of climate change to the rich biodiversity of the mediterranean biome
might include establishing new protected areas within areas projected to remain stable,
improving land management, and restoring native habitat in southwest Australia. In
particular, restoration efforts could focus on creating corridors or stepping stones of
native habitat to connect isolated remnant vegetation patches in the areas with project-
ed MCE contraction to the native habitat in the areas projected to remain stable. While
this strategy has been advocated before [41, 42], and is currently underway in projects