Mar. 6,
2013 — Climate change could see dozens of lizard species becoming extinct
within the next 50 years, according to new research published today. The often
one-directional evolutionary adaptation of certain lizard species' reproductive
modes could see multiple extinctions as the global temperature increases.
Globally it
has been observed that lizards with viviparous reproduction (retention of
embryos within the mother's body) are being threatened by changing weather
patterns. A new study suggests that the evolution of this mode of reproduction,
which is thought to be a key successful adaptation, could, in fact, be the species'
downfall under global warming.
Dr Daniel
Pincheira-Donoso, from the School
of Life Sciences
Researchers,
including academics from the University of Exeter, investigated the hypothesis
that historical invasions of cold climates by Liolaemus lizards -- one of the
most diverse groups of vertebrates on earth -- have only been possible due to
their evolution to viviparity (live birth) from oviparity (laying eggs).
Remarkably, once these species evolve viviparity, the process is mostly
irreversible and they remain restricted to such cold climates.
By analysing
this evolutionary transition in the lizards' reproductive modes and projecting
the future impact of climate change, the scientists discovered that increasing
temperatures in the species' historically cold habitats would result in their
areas of distribution being significantly reduced. As a consequence, if global
warming continues at the same rate, viviparous lizards are facing extinction in
the next few decades.
Dr Daniel
Pincheira-Donoso is one of the few people in the world who works on the ecology
and evolution of these lizard species. He said: "Lizards' reproduction is
largely linked to climatic temperatures and viviparous species are usually
found in cold environments. When reptiles initially moved to colder areas they
needed to evolve emergency measures to succeed in these harsh places, and we
believe viviparity is one of these key measures. However, this transition is
mostly one-directional and unlikely to be reversed. Rapid changes in the
environment's temperature would demand rapid re-adaptations to secure the species'
survival. Through the research we found that over the next 50 years nearly half
of the area where these species occur may disappear, causing multiple
extinctions due to climate change."
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