Past, Present, and Future Climate Change: Can Palaeoecology Help Manage a Warming World? - Biodiversity Conservation and Environmental Change - page 111

Improved modelling that incorporates multiple drivers of species and biome distributions,
alongside hindcasting and analysis of future uncertainties, will help in understanding the
range of possible future scenarios. Such modelling can be integrated into adaptive ecosystem
management, because surprises are inevitable, given the uncertainty of future climate change
predictions, and the possibility that changing biotic interactions, trophic cascades, alien spe-
cies, and pathogens might lead to ecosystem reorganization and novel communities (Parme-
san 2006, Williams and Jackson 2007, Spangenberg et al. 2012).

No-analogue futures?

Ecosystem and species responses to the interacting effects of climate change and land cover
transformation are uncertain. Current rates of climate change are higher than the MWP and LIA
and this may impact on how well species and ecosystems can respond through migration and
adaptation (Diffenbaugh and Field 2013). Furthermore, CO 2 , rainfall, and temperatures will
occur in combinations never seen before, and by 2100, no-analogue climates will be common in
tropical and subtropical regions (Williams and Jackson 2007, Williams et al. 2007). Furthermore,
species will respond and migrate at different rates, some arriving in new climate space quickly,
others surviving in areas where they will no longer be able to recruit (Jackson and Sax 2009).
Some species may adapt by changing their life history or physiological tolerance, which will
render simulations based on current distributions or tolerances inaccurate.
Climate change can cause new ecological communities to assemble, because species
responses to climate are individualistic; species reshuffling can occur as species with differ-
ent tolerances to temperature, rainfall, and other climate parameters adjust their distribu-
tion. Thus, long-lasting species associations can start to break down and new species
combinations of species will arise (see Figure 5.11) (Williams and Jackson 2007). Such

(a) (b)

Present
Climate
Space

Future
Climate
Space

Species 2 Species 3 Species 3

Species 2

Species 1

Species 1

Climate Variable 1 Climate Variable 1

Figure 5.11 A conceptual diagram showing how no-analogue communities arise in novel climates. The
light grey oval indicates climatic conditions. Dark grey shapes indicate occurrence of a species. Dotted
lines indicate the fundamental niche in terms of climate variables 1 and 2. (a) Species 1 and 2 coexist in
the present climate space. (b) Species 1 and 3 coexist in the future climate space—a new species associa-
tion. Adapted from Williams and Jackson (2007).