Dispersion and Colonization
by Mezenc Marmots

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Analysis of Demographic Accidents

Paysage du Mézenc
The demographic growing of Alpine marmots (Marmota marmota) introduced between 1980 and 1990 around Mezenc summit was not linear.
The observation of the chart of strength shows three moments when the number of marmots observed was lower than the former year. This happened for the years 1993, 1997 and 2001.
In these three cases, negative increasing rates were observed. The perturbation affected numbers as well as number of known or occupated sites, and the annual occupation factor (COA).
The quantitative terms of comparison are gathered in the table here-under.

Period1992 19931996 19972000 20012008 20092014 2015
Numbers before107171243504603
Numbers after96145204411479
Increasing Rate- 10 %- 15 %- 17 %- 18 %- 20 %
Nb Sites Known before/after23/2734/3747/53107/111137/137
Nb Sites Occupated before/after21/2531/3241/4498/8293/88
Annual Occupation Factor %91/9391/8687/8392/7468/64


Look at the mapping of each demographic accident:

Citation : mezenc.linneenne-lyon.org/cartoacc0.php - © 2012-2024, Le Berre M., Metral J. (ONCFS), Putz O. (LPO) & Ramousse R.

Dernière modification le 1970-01-01 01:00:00