Effets de la pression anthropique sur le comportement alimentaire de la marmotte alpine. Hiking impact on feeding behavior in Alpine marmot.

Résumé

Foraging in Alpine Marmot, an hibernating rodent, is a vital activity as marmots are active only during six months per year in order to insure the energy intake for active period and fat accumulation for winter period. In summer, perturbation due to an increasing hiking pressure could possibly affect marmot behaviour. Effect of different hiking pressures on foraging behaviour of marmots were investigated in two family groups during three different months. In each group of marmots, diet has been described and quantified using the micrographic technique for feacal analysis. Activity ryhthm has been assessed by scan sampling. Vigilance (look-ups while feeding) and tolerance to human presence (flight distance and time spent in the burrow after being disturbed) has been quantified by focal animal sampling. Marmots under the higher human pressure, on the contrary of the others, showed: 1. In August, - a less selective diet especially for Fabaceae - a decrease of feeding activity coinciding with daily tourist rush hours and during other periods an increase of this activity near the burrows. - a higher frequency of look-ups while feeding. 2. In September, - an original behaviour pattern : feeding on plants growing under stones. Tolerance to human presence by these marmots was always higher. Anthropic pressure seems to induce a qualitative and quantitative fall of diet through an increase of vigilance and a decrease of diet selectivity due to the difficulty to exploit their whole home range. These negative effects on marmot survival could be balanced by the increased tolerance to human presence.