Geoscience Reference
In-Depth Information
Table 4.2
Examples of methods used to project the impacts of future climate change on species and ecosystems, summarizing some of the
advantages and disadvantages of e
ach
Tool
How it works
What it tells us
Advantages & disadvantages
Paleoecology:
clues from the
past
Uses fossil data to
reconstruct how species and
ecosystems responded to
past climate changes.
“Greenhouse climates” in the past were generally not
favourable for the persistence of species (Mayhew
2012) and even relatively slow climate changes have
been associated with surprisingly abrupt regional
change. Past climate change has been associated with
large-scale shifts in biomes, species extinctions, and
re-assortment of species assemblages creating novel
communities (Williams and Jackson 2007). Species
responded individualistically to climate change, with
some able to disperse rapidly over long distances,
while others expanding from small populations in
climatic refugia.
While some examples of rapid warming occurred
on regional scales within just a few decades and
thus provide useful comparisons, no past changes
are exact analogues of the change projected for the
next century. Past responses of biota to climate also
occurred in intact, unfragmented landscapes without
human impacts.
Comparative
phylogeography
Past climatic changes have
driven changes in species
distributions and these
changes have left “genetic
signatures” in present day
species and populations.
Parallel evolutionary patterns in different groups of
species indicate common responses to past climatic
luctuations. In areas of relatively high geographic
relief, species were able to disperse in response to
climatic change. In areas of low relief, however,
species are most likely to have persisted in the
landscape within patchy, localized refugia, rather than
moving long distances (Byrne 2007).
Phylogeographic comparisons are a useful complement
to paleoecological studies based on fossils, especially in
areas where the fossil record is incomplete.
Extrapolation
from recently
observed
changes
Long term datasets of
species phenology (life
cycles), distributions,
morphology, and physiology
provide information on
the sensitivity of species to
climate change, and their
ability to adapt.
Climate change over recent decades has affected
species and ecosysems in all regions (Chen et al.
2011), (Thackeray et al. 2010). Changes have
been observed in life cycles, distributions, genetic
composition, morphology, and productivity (see
(Steffen et al. 2009).
Long term datasets in Australia are relatively rare
compared to the Northern Hemisphere, limiting
investigation of climate sensitivity. Uncertainty
remains about the role of non-climatic drivers, such
as changes in ire, grazing and land-use. Extrapolation
to future warming is limited by lack of understanding
of the linearity of responses, and the wide variability
displayed even by closely related species.
