Physiological responses of Dipodomys merriami in grasslands and shrublands in the Chihuahuan Desert

摘要

The Chihuahuan Desert has been overgrazed by livestock ranching since the 16th century. This has changed the structure and dynamics of the ecosystem, and native species have developed physiological adaptations to survive these vegetation changes. We evaluated the changes in packed cell volume (PCV) and plasma protein of Dipodomys merriami, Merriam's kangaroo rats, inhabiting shrubland and grassland areas at Mapimi Biosphere Reserve, Chihuahuan Desert, Mexico. We captured 57 individuals from two vegetation types in March-April for two years. We found higher kangaroo rat packed cell volume in grassland than shrubland. However, the plasma protein/packed cell volume ratios were not significantly different between rats from both vegetation types, suggesting that an increase in PCV is a consequence of dehydration. Monitoring the packed cell volume can be a useful and rapid screening tool to assess responses to changes in habitat degradation in arid areas.