Rock glacier and unvegetated ice-dominated moraine

As indicated by its name, a rock glacier is a mixture of frozen rock detritus and ice. It takes the form of a lobate, spatulate or tongue-like mass of angular boulders, behaving as a lava flow, due to the presence of internal ice that flows very slowly under gravity forces. This movement is 100 to 1000 times slower than in a true glacier. The origin of ice of rock glaciers can be glacial or periglacial; thereby, rock glacier occurs also when permafrost (frozen soil) creeps downslope during thaw periods. This habitat type is endangered by the global warming of the climate. Moraines are glacially formed accumulations of unconsolidated mineral debris. Ice-dominated moraines occur in the vicinity of retreating glaciers. Few organisms have the ability to colonize these particular habitats, because of the low temperatures and the mobility of the substrate. The flora is limited to pioneer plants, lichens and some vascular plants, occurring principally on the lateral and terminal borders of the rock glacier. Active rock glaciers have a very low vegetation cover, while inactive or relict ones are characterized by higher covers (>70%). The diversity of the fauna increases with the vegetation cover; it includes Collembola, spiders, Homoptera, Diptera, parasitoid wasps, ground beetles and aphids. These ice-rich formations are found in altitude or in high latitudes. In Europe, they occur only in the high mountain regions of the Alps, the Pyrenees, the Scandes, and in the arctic region. 

Indicators of good quality:

Independently of the poverty of the flora and fauna of this habitat, quality can be estimated by the degree of activity of the rock glacier. An active rock glacier moves because it has ice-rich frozen debris and its internal temperature is low. Inactive and fossil rock glaciers haven’t coherent ice-core and stop moving. 

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats