Global warming and marmot's hibernation: Mathematical modeling of burrow temperature in changing climate [Le réchauffement de la planète et l'hibernation de la marmotte : modélisation mathématique de la température du terrier au cours du changement de climat].

Résumé

Temperature inside burrow is mainly determined by surrounding ground temperature, which is, in its turn, determined by temperature of surface and underlying thermoneutral layers. The most obvious method of burrow temperature estimating in case of climate changes is mathematical modeling, which showed good results in nowadays burrows temperatures’ analyses. Model shows that temperature regime changes depend on burrows depth and speed of climate changes, because deep ground warming is an inertial process. Since there is no generally accepted global warming forecast we analyzed three possible scenarios. 1. Equal 3° C increase of all mean month temperatures (equal scenario). This amplitude is commonly used in discussion about Holocene climate changes. 2. Rising of only winter half-year temperatures (from October till March, winter scenario). 3. Summer scenario: rising of summer half-year temperatures (from April till September). All scenarios result in rising of every month’s average temperature. In « equal » and « winter » scenarios temperature during hibernation is considerably higher than nowadays. For example, for Ukrainian population of Marmot bobak it is shown temperature increase out of optimum range (0 +5° C) at depth from 1.4 to 4.5 m. Transbaikalian Marmota sibirica’s deep (3m) burrows’ temperature remains optimal and period of negative temperature at 1.5 m depth decreases from 6 to 4 months. « Summer » scenario affects mainly summer and autumn burrow temperatures, so most changes will be in marmot’s foraging activities and behavior. Model shows that climate changes affect marmot’s populations variously, depending on environmental conditions. Enhancing precision of climate changes forecast let us make more detailed estimates.