Monday 5 December 2016

Adders in the Réserve naturelle nationale de la vallée de Chaudefour, France

The Common Adder is not found in the warmer parts of France and is generally to only be found in the north and east. As such I thought this information about Adders in the Réserve naturelle nationale de la vallée de Chaudefour, France maybe of some interest. It certainly sounds like a great place to visit if nothing else.

The Vallée de Chaudefour is a glacial valley in the heart of the volcanic massif du Sancy in the Auvergne National Park with a unique range of species many of which are unique to mountain environments. It has no less than 976 species ranging from mammals such as chamois, mountain sheep and marmots to the Apollo butterfly, (Parnassius apollo), rock thrushes (Monticola saxatilis), and a population of Common Adders, (Vipera berus).

The Chaudefour Valley which is between 1137 and 1854 m above sea level has 820 ha of terraced landscape was classified as a National Nature Reserve in 1991. The syndicate of structures that manage the park together with the ONF, (Office National des Forêts), put in place a program that ran from 2011 to 2016 to record and document the adder population.

The inventory has been realised by Frederic Durand, of the Société d’histoire naturelle Alcide-d’Orbigny. The methodology consisted of field surveys with a systematic search and in all 248 Adders have been counted inside the reserve and 19 outside the reserve. They have all been identified, named with an individual tracking record. The colouring, the patterns of the head and arrangement of cephalic scales allow individual photographic recognition, rather like finger prints in humans.

The effective boundary between where the Asp Viper is to be found at lower altitudes and the Adder is directly on the boundary of the reserve where a hybrid pregnant female was found and is the third known case of such a hybridization identified in France.

In June of 2016, officers from the departmental ONCFS, (Office National de la Chasse et de la Faune Sauvage), for the Puy-de-Dôme participated in a day of recognition where 1 Grass snake  and 19 Adders were measured, weighed and photographed.

The ONCFS officers were able to practice finding the vipers which can be hard to find, especially males, (females that bask on rocks to thermoregulate are usually easier). They also had the opportunity to handle the snakes and discuss the monitoring program with specialists, (sounds like a fun day out).

The implementation of this virtually unprecedented comprehensive monitoring program and the relatively large number of snakes detected where they were thought to be scarce is very interesting given that overall this species is rapidly becoming threatened in much of its range. In general the loss of habitat and fragmentation of the population elsewhere has pushed this species from the status of "least concern" to "vulnerable" category on the 2015 red list. 

Principle source ONCFS

Office National des Forêts  ONF

Réserve naturelle nationale de la vallée de Chaudefour HERE

Adders in France HERE

Cheers, Chris