Mediterranean Ecosystems Worldwide: Climate Adaptation - Recent Advances and Issues in Environmental Science - page 34

were classifi ed as both protected and converted were considered converted. From
this combination of grids, we could determine the percent of the MCE that is pro-
tected and converted to human land uses.
The MCE at the end of the 20th century covered just over 1.5 million km 2 ,
according to Aschmann's [17] defi nition. This is a conservative defi nition of the
MCE and refl ects the core areas of the mediterranean biome. For comparison, on a
commonly used map the mediterranean biome covers 3.2 million km 2 [2], or over
twice the area in the current MCE. Approximately 60% of the current MCE occurs
in the Mediterranean Basin, and covers a portion or all of the following countries:
Algeria, Cyprus, Greece, Iran, Iraq, Israel, Italy, Jordan, Lebanon, Libya, Malta,
Morocco, Portugal, Spain, Syria, Tunisia, and Turkey. The remaining MCE occurs
in Australia (25%), the US/Mexico (9%), Chile/Argentina (4%), and South Africa
(2%).
The majority of AOGCM and emissions scenario projections of the MCE at the
end of the 21st century (or future MCE) are larger than the MCE at the end of the
20th century (or the current MCE). The median future MCE increases to 106, 107,
or 111% of its current size, for the low, medium, and high emissions scenarios,
respectively (Figure 1). However, this pattern is not consistent within each region.
Instead, there is a disparity between the regions with some projected to experience
an increase in the MCE in the future and some projected to experience a decrease
in the MCE. Almost all of the AOGCM simulations project an increase in the MCE
in the Mediterranean Basin with the median future MCE increasing to 115, 126,
or 132% of its current size for the low, medium, or high emissions scenarios, re-
spectively. The median projected increases are greater in Chile/Argentina, rang-
ing from 129% for the low to 153% for the high emissions scenario. In the US/
Mexico region, the projected change in the MCE is less dramatic, with the median
future MCE decreasing to 96, 95, and 94% of its current size, for the low, medium,
and high emissions scenarios, respectively. In South Africa, greater than 90% of
the AOGCM simulations project a decrease in the future MCE, with the median
estimates ranging from 83% of the current MCE for the low to 60% for the high
emissions scenario. In Australia, the projected area reduction is more extreme, with
median estimates ranging from 77% of the current MCE for the low to 49% for the
high emissions scenario.
By overlaying all of the future MCE projections, we were able to map all of the
grid cells on the globe where the MCE is likely to expand, contract, and remain stable
with varying levels of confi dence (Figure 2). We show that there are areas of contrac-
tion even within regions that are projected to have a net increase in the MCE. For
example, the median projection of the future MCE in the Mediterranean Basin is larger
than the current MCE, but most AOGCM simulations project contractions in Morocco
and in the Middle East. The geographic separation between the areas of contraction
and expansion within each region highlighted in Figure 2 will have important implica-
tions for adaptation of native plants and animals with limited dispersal or migration
capabilities.