Data from: The future distribution of the savannah biome: model-based and biogeographic contingency

The extent of the savanna biome is expected to be profoundly altered by
climatic change and increasing atmospheric CO2 concentrations. Contrasting
projections are given when using different modelling approaches to
estimate future distributions. Furthermore, biogeographic variation within
savannas in plant function and structure is expected to lead to divergent
responses to global change. Hence the use of a single model with a single
savanna tree type will likely lead to biased projections. Here we compare
and contrast projections of South American, African, and Australian
savanna distributions from a physiologically-based statistical
distribution model - the Thornley transport resistance model (TTR-SDM) -
and three versions of a dynamic vegetation model (DVM) designed and
parameterized separately for specific continents. We show that attempting
to extrapolate any continent-specific model globally biases projections.
By 2070 all DVMs generally project a decrease in the extent of savannas at
their boundary with forests, whereas the TTR-SDM projects a decrease in
savannas at their boundary with aridlands and grasslands. This difference
is driven by forest and woodland expansion in response to rising
atmospheric CO2 concentrations in DVMs, unaccounted for by the TTR-SDM. We
suggest that the most suitable models of the savanna biome for future
development are individual-based dynamic vegetation models designed for
specific biogeographic regions.