Thelizards and lizards will die of heat, literally,if CO 2 emissions are not reduced, according to a study carried out by an international team of 26 scientists, with Spanish participation. Researchers hope6% extinction of these reptile species by 2050, and 20% by 2080.
In total, according to a mathematical model validated with field work carried out on four continents,Some 1,300 of the 5,100 known species of saurians could disappear through the gradual extinction of 39% of their local populations. The disappearance of these animals, which number more than 5,000 species, would cause apopulation explosion of their prey, such as insects, invertebrates, and small vertebrates.
The investigation began with the finding that certain populations ofbog lizardZootoca vivipara)of France had become extinct. Likewise, team members verified, out of a total of 48species of Mexican lizards of the genusSceloporus, that the animals had disappeared in 12% of the 200 sampled localities, despite the fact that their habitat remained apparently intact. These findings led the team to develop an artificial lizard model with microchips that measured operating temperature under different conditions for four months, both in locations where populations of these reptiles had survived and where they had disappeared. The test results were conclusive:in places where extinctions had occurred, lizards would not have had time to feed or reproduce properly, since the high temperatures would force them to stay most of the time sheltered in their shelters.
The new model relates the parameters of the thermal physiology of lizards with the predictions of global warming. “Lizards have a series of physiological requirements that limit their behavior and this fundamentally interferes with the time of activity available both to feed themselves and to reproduce and for all their vital functions”, explains Ignacio De la Riva, researcher at the National Museum of Natural Sciences (CSIC) and co-author of the study.
Mountain and viviparous, the most threatened
The most threatened species will be mountain speciesbecause they tend to change their distribution area altitudinally, that is, if a species lives in a cold area and the climate is getting warmer, it will need to go up and in some cases it will find that it no longer has anywhere go ?, declares De la Riva. Added to this is the fact that lowland species are going to colonize higher and higher areas and are going to displace those in the mountains. Also, viviparous lizards are more in danger than oviparous ones.
One of the main reasons for these extinctions is thatlizards adapt very slowly to rising temperatures. “The time frame to reach a higher body temperature is too long for lizards because the genetic bases of these traits are not very heritable,” says Sinervo.
Many of these extinctions, especially those of those species that inhabit tropical mountainous regions, could be prevented if successful in reducing global CO emissions2by 2080. And as an immediate solution, the researchers propose “multiplying the shadow areas and the water points.”
