The second type of biotope is often found alongside paths and roads, where the forest is more open. Sometimes the openness is the result of cutting trees, as is the case on location 12 and 13. Cutting of trees is in this part of the Vercors always done on a small-scale basis. Old trees growing at accessible locations are selected. By doing so, the structure of the soil is never disturbed on a large scale. This type of forestry can, in our view, not regarded as a potential threat for the occurrence of Orchis spitzelii. On the contrary, we have the impression that a complete banning of forestry would lead to the disappearance of open locations at the fringes of the forest, which will undoubtedly diminish the possibilities of Orchis spitzelii. Accompanying species include trees as Pinus sylvestris, Picea abies and Fagus sylvatica. Additionally, species which have their optimal position in forest fringes are accompanying species such as Carex flacca, Gentiana angustifolia, Polygala ssp., Cytisus sesselifolius, Globularia nudicaullis and Juniperus communis.. Locations 9 and 10 and most locations 15-20 can be considered as belonging to this type of location.
The Open Forest
It should not be overlooked that coniferous forests on nutrient poor soils with a thin layer of humus in the south-eastern Vercors, have always an open structure. Therefore, these locations have much in common with the previous type of location. Pinus sylvestris and Picea abies are characteristic trees for this type of forest. A typical example is the forest on location 36, where nearly 400 plants could be found, growing in a vast area. This forest is located at 1100 meters, which enables many southern species to grow there. Due to the open structure of the forest, many species can be found here such as Coronilla vaginalis, Cytissus sesselifolius, Coronilla minima and Carex flacca.
Probably, there are more locations in forests, where the potentials for Orchis spitzelii are high. But the total surface of adequate forests in the south-eastern Vercors is considerable. When the vegetation is low and scarce, it is necessary to search the total surface of the forest. In such a situation Orchis spitzelii can grow everywhere. We investigated some forests of this type with a quite rich type of vegetation, but we could not find any Orchis spitzelii. The locations 29, 30, 36 and 37 belong to this category.
Threats and Further Investigation
In all cases Orchis spitzelii is growing in an open vegetation or on a vegetationless substrate. There is always a dynamic factor. The stability of these dynamic influences is necessary for the occurrence of the species in the south-eastern Vercors. The influence of grazing on the distribution is not clear. Indeed, at the richest location in the Vercors in the neighbourhood of Chichiliane (36), small-scale grazing can be recognised which increases the dynamic situation for the vegetation. However, one cannot exclude the possibility that the number of plants would be higher without grazing. Therefore, further research on the effect of grazing is necessary.
Another potential threat is the expansion of skiing facilities on the slopes. However, taking into account the current distribution on the slopes, there is little evidence for that type of development, as the southward inclined slopes are rapidly loosing snowcover after heavy snowfall. These slopes are not suitable for skiing facilities. Stopping forestry activities is, in our view, a potential threat. This will undoubtedly lead to a decrease of open situations in the forests. Stopping of grazing activities in open forests can have the same effect. The maintenance of the openness of the forest is an important issue.
The most significant threat is the lack of knowledge of this species and the actual distribution pattern in the area. Without a profound knowledge of the species an adequate protection is not possible. On the basis of the current results of our research in a small part of the south-eastern Vercors, we assume that substantial populations of Orchis spitzelii can be found elsewhere in the Vercors, in the D�voluy, the Chartreuse, the Diois and the Baronnie.
As argued in the introduction of this article, Orchis spitzelii is one of the rarest European orchids. The populations in the Vercors are very relevant for the knowledge and the protection of the species in a European context. Therefore, we have the intention to realise further research in the Vercors in the coming years. We will pay attention to the distribution, the structure of the various populations and the pollination of Orchis spitzelii. This type of research can only be done in the first two weeks of June. We have the intention to realise this research with the help of an internationally orientated working group. People who are interested in this type of research can contact us via [email protected]. Seven persons told us already that they are willing to cooperate.
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