An earlier rather common but rapidly declining species. The Dutch elm and ash dieback diseases are major threats.(Proposed by Göran Thor).
Suggested assessment by proposer:: VU on the A criterium (A2bc+3bc+4bc), population decrease 45 (40-90) % over 100 years.
Gyalecta ulmi is widely distributed on deciduous trees in most of Europe eastwards to Caucasus.
The species has decreased rapidly and is red-listed in e.g. Austria, Finland, Germany, Norway, Sweden and Switzerland.
The species is found mainly on Fraxinus spp. and Ulmus spp., very rarely on other tree species or on calcareous rocks or dolomite. It is mainly found in open forests as wooded meadows and is more common on pollarded trees.
The Dutch elm disease and the ash dieback disease are major threats. The species is most probably also sensitive to air pollution.
Remaining large populations should be protected. Focus should be on the populations on rocks and other tree species Fraxinus spp. and Ulmus spp.
The Information System on Italian Lichens. http://dbiodbs.univ.trieste.it/italic/italic03
Rote Listen Deutschland. http://www.bfn.de/0322_rote_liste.html
Red Lists: Threatened species in Switzerland. http://www.bafu.admin.ch/publikationen/publikation/01688/index.html?lang=en
Red List of Endangered Lichens in Austria. http://www.uni-graz.at/~hafell/redlist.htm