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238 THE LICHENOLOGIST Vol. 23 FIG. 1. Vegetation on a tree-covered spur of a mountain with a north-east facing slope (left part) and a south-west facing slope (right part). Distribution of cluster-groups. The vegetation was studied by cluster analysis and by principal component analysis (PCA). Good correlations between the vegetation and the distribution of abiotic factors such as light and pH were observed. A cluster analysis of the complete research area showed several groupings (Fig. 1, A-F) each representing homogeneous vegetation according to the rules of plant sociology. The principal species in each group, higher plants as well as lichens and mosses, and their abundance are given in Fig. 2. No lichens were present (epiphytic lichens were excluded) in the cluster groups A and B from the north-east facing slope. In group C the first species of Cladonia appear, but only C.furcata is found with large numbers of thalli. The main occurrence of Cladonia is in the cluster groups E and F, with a marked increase in Parmelia conspersa and Polytrichum piliferum in cluster group F. This means that on the southern-facing slope lichens and mosses could be used together with the higher plants for the definition of the cluster groups. A PCA of both slopes together included the cryptogams and resulted in a clear picture. Only the occurrence of the plants and not their abundance was used. The resulting scatter showed a gradient that could be separated into 10 parts (Fig. 3). The gradient shows a continuous change starting from the lower part of the northern slope, passing upwards to the transition zone between the two slopes and ending in three open areas at the margin of the south slope. A comparison between PCA and cluster analysis shows a high degree of conformity. The distribution of abiotic factors was also investigated by PCA and a high degree of conformity between the distribution of vegetation and the light intensity (Fig. 4), the pH and the ground cover by dead leaves was found.
1991 Microclimate influences on lichens—Canters et al. 239 Oxolis acetosella IW.VJ H * » * »1 Cardamine pratensis I.V.'.'.I Mercurialis perennis Anemone nemoroso Lamiastrum galeobdolon Dryopteris filix-mos Festuca altissima r Luzula luzuloides [•:• Polypodium vulgare I Polytrichum formosum Hypnum cupress i for me Dicronum scopar/um Avenella flexuosa Clodonia furcato Pleurozium schreberi Fagus sylvatica (seedling) Hierocium lacnenalii and H. glaucinum Clodonia coniocraea Cladonia orbusculo Quercuspetraea (seedling) Clodonia ciliota Cladonia squamoso Cladonio rangiferina Dicronun spunurn Calluna vulgarls Hieracium umbellatum Polytrichum piliferum Genista pilosa Parmelia conspersa X-Uv II LZZJL E23L •:-:ii II :VMK-:-:-:-II X-ires^k-: \mm\ tv 1 1 1 1 1 1 II II II II 1 II X-ll 1 II 1 M^FXy^ •XU-:- iK-x '•il.' :-:->HF>:-:-H it-:-'.-XJ N \[yy. ICv/ II 1 '.*. W.V.I lA A A A A 1 '.V.V.V.i 1 * A A A J s?i:-ga C-:-:*:-.M :•:•:•:•! Pv>:-:1 Ml WKMMMM If: •.vHEv.v] A A A A '!J t*i*i%*i"»%"»1 r A A A A AI CVXVXVH 1 1 1 1 1 It-: JI± It-: II II y-iwmm '»]••• 1 tvX-M lf#?SSSi| | I
Page 1: Lichenologist 23(3): 237-252 (1991)
Page 5 and 6: 1991 Microclimate influences on lic
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