Fungerar AHA-metoden för epifytiska lavar och mossor?

En studie av naturvärdesindikatorer hos träd i park- och kyrkliga kulturmiljöer

Abstract

Old trees in cultural environments are receiving increasing attention in nature conservation due to their high conservation values and provide important habitat for endangered plant and animal species. The purposes of the study were to investigate whether Sörensson's AHA-method is applicable also to mosses and lichens, as well as to compare two environments with old trees. 443 trees were inventoried in Kristianstad, of which 230 in Tivoliparken and 213 in Östra begravningsplatsen. The trees were assessed based on the occurrence of: cavities, barkless areas, and so on. These findings were used to assign each tree to the five AHA classes of varying conservation value. Trees were also searched for predetermined lichens and mosses signalling high conservation value, and a simple count was made of the total number of trivial cryptogam species on each tree. Tivoliparken had a wider scatter of trees among the AHA classes; 56 in the highest value classes (class I and II), 114 in class III, and 60 as resource trees. At Östra begravningsplatsen, half of the oldest trees were in the two highest value classes and 93 in class III. The remaining trees ended up as resource trees. In total, 89 records of 6 signal species were made, and one wood fungus. There was a significant association between AHA class and richness of trivial species when trees of all species were pooled, but no association when beech and linden were assessed separately. These results suggest that the AHA method does not work on cryptogams.