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Recently, Sinervo et al. (2010, Science, 328: 894–899) reported declines of lizard biodiversity due to local warming trends and altered thermal niches. Herein, we applied the Sinervo et al. (2010) physiological model to predict the local extinction risk of three species of lizard from Patagonia. Whereas the previous model used a single equation (for the extinctions of Blue Spiny Lizard (Sceloporus serrifer Cope, 1866) in the Yucatan Peninsula) relating environmental temperatures (Te) to hours of restriction (i.e., the period when lizards are forced into retreat sites because environmental temperatures are too high), we measured habitat-specific equations for the Te values of each species. We analyzed the vulnerability of Darwin’s Ground Gecko (Homonota darwinii Boulenger, 1885), Bariloche Lizard (Liolaemus pictus (Duméril and Bibron, 1837)), and Mountain Slope Lizard (Liolaemus elongatus Koslowsky, 1896) to climate change considering thermal physiological constraints on activity during the reproductive period. While Sinervo et al. (2010) predicted that the Phyllodactylidae family will not suffer from impacts of climate change, our physiological model predicted that 20% of the H. darwinii populations could become extinct by 2080. The physiological model also predicted that 15% of L. pictus populations and 26.5% of L. elongatus populations could become extinct by 2080. The most vulnerable populations are those located near the northern and eastern boundaries of their distributions.

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The coexistence of desert small mammals can be explained by differences in microhabitat use, morphology, body size, diet and foraging. The aim of this study was to quantify the structure of small mammal assemblages and the seasonal fluctuations in their abundance using mark – recapture techniques in habitats of different structural heterogeneity (mesquite forest, creosotebush community, and sand dunes) in the temperate Monte desert of Argentina. Habitat heterogeneity was characterised by 10 vegetation variables. The mesquite forest and the creosotebush community showed the highest diversity and habitat heterogeneity. The relative abundance of each species underwent remarkable variations between habitats. The sigmodontinae rodents

Modes of locomotion and escape tactics are attributes that affect the structure of animal communities, promoting exploitation of different microhabitats and the coexistence of different species. Bipedal locomotion is considered to be more effective than a quadrupedal gait in escaping attacks by predators because it allows for higher speed, a faster response to attack, sudden changes of direction and better detection of aerial raptors. The aim of this study was to determine the type of locomotion used at the moment of escape by three rodent species of the Monte desert –Eligmodontia typus, Akodon molinae and Graomys griseoflavus. The study was carried out in three plant communities of the Ñacuñán Reserve (Mendoza). All three species showed differences in both mode of escape and locomotory pattern. Graomys griseoflavus exhibited the highest proportion of escapes using quadrupedal saltation. The mode of locomotion employed by E. typus varied according to the type of plant communities it inhabited. Those occurring at open sites (Medanal community) exhibited a greater propensity to jump during escapes than those from more sheltered habitats (Algarrobal community). Akodon molinae relied primarily on a quadrupedal gait when fleeing from predators, which would explain its greater dependence on plant cover. Therefore, the morphological and behavioural characteristics of these species are related to their mode of locomotion and the strategies they employ to diminish the risk of predation.

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