Carbon Dioxide and Earth's Future Pursuing the ... - Magazooms

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conditions within the cell, and thus provide imprecise values of the probability of occurrence of
species along a thermal gradient.”
In testing this “local high-elevation habitat persistence hypothesis,” as they described it, the
group of Swiss, French and Danish researchers assessed “whether climate change-induced
habitat losses predicted at the European scale (10 x 10’ grid cells) are also predicted from localscale
data and modeling (25-m x 25-m grid cells).” And in doing so, they found that for 78
mountain species modeled at both European and local scales, the “local-scale models predict
persistence of suitable habitats in up to 100% of species that were predicted by a Europeanscale
model to lose all their suitable habitats in the area.”
In discussing their findings, Randin et al. suggested that the vastly different results they
obtained when using fine and coarse grid scales might help to explain what they call the
Quaternary Conundrum, i.e. “why fewer species than expected went extinct during glacial
periods when models predict so many extinctions with similar amplitude of climate change
(Botkin et al., 2007).” In addition, they noted that “coarse-resolution predictions based on
species distribution models are commonly used in the preparation of reports by the
Intergovernmental Panel on Climate Change,” which are then used by “conservation planners,
managers, and other decision makers to anticipate biodiversity losses in alpine and other
systems across local, regional, and larger scales,” but which, unfortunately, give a highlywarped
and erroneous view of the subject.
Moving one year closer to the present, Erschbamer et al. (2009) documented and analyzed
changes (from 2001 to 2006) in plant species number, frequency and composition along an
altitudinal gradient crossing four summits from the treeline ecotone to the subnival zone in the
South Alps (Dolomites, Italy), where minimum temperatures increased by 1.1-2.0°C during the
past century with a marked rise over the last decades. In describing their findings, the four
researchers stated that “after five years, a re-visitation of the summit areas revealed a
considerable increase of species richness at the upper alpine and subnival zone (10% and 9%,
respectively) and relatively modest increases at the lower alpine zone and the treeline ecotone
(3% and 1%, respectively).” In addition, with respect to threats of extinction, they reported
that “during the last five years, the endemic species of the research area were hardly affected,”
while “at the highest summit, one endemic species was even among the newcomers.”
The Austrian scientists thus concluded that “at least in short to medium time scales, the
southern alpine endemics of the study area should not be seriously endangered.” Moreover,
they indicated that “the three higher summits of the study area have a pronounced relief
providing potential surrogate habitats for these species.” And they also reported that “recently
published monitoring data from high altitudes indicate a consistent increase of species richness
in the Alps,” citing the work of Pauli et al. (2007) and Holzinger et al. (2008).
Working contemporaneously in the nearby Swiss Alps, Stocklin et al. (2009) studied the
consequences of the highly structured alpine landscape for evolutionary processes in four
different plants (Epilobium fleischeri, Geum reptans, Campanula thyrsoides and Poa alpina),
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