caa a22 4500 475751647 CHVBK 20180406123525.0 cr unu---uuuuu 170329e20000601xx s 000 0 eng 10.1023/A:1009832507791 doi (NATIONALLICENCE)springer-10.1023/A:1009832507791 Community structure of epilithic lichens on the cliffs of the Niagara Escarpment, Ontario, Canada [Elektronische Daten] [Uta Matthes, Bruce Ryan, Douglas Larson] The spatial variation in epilithic lichen community structure was investigated as part of a larger study of the vegetation and ecology of the tall limestone cliffs within the Niagara Escarpment Biosphere Reserve in southern Ontario, Canada. The cover of all lichen taxa was visually estimated for a total of 199 samples taken from the top, middle, or bottom of the cliff face at five sites. Twelve environmental variables were also measured. Twenty-seven lichen taxa were identified on the samples. Multivariate ordinations of species composition (DCA, CCA, PCCA) revealed variation in community structure on multiple scales, but no groupings of sites that would have suggested the presence of several distinct species assemblages. A gradient in species composition from north to south, most clearly reflected in the decreasing cover of foliose and fruticose species, may reflect a gradient in human disturbance. There was also intermediate-scale patchiness in species composition in a horizontal plane across cliffs, but despite earlier claims made in the literature, no evidence of vertical zonation of the lichens on cliffs was found. Species composition also responded to small-scale factors possibly related to exposure, light, or moisture. Unlike community composition, the total cover of all lichens was homogeneous over large spatial scales and varied only on a small scale, illustrating that scale as well as resolution of a study may influence the ecological patterns seen. More than half of the species found on the Niagara Escarpment are rare on rock substrates elsewhere in southern Ontario, and two are new for North America (Candelariella heidelbergensis (Nyl.) Poelt and Lecanora perpruinosa Fröberg). The result that cliffs support a distinct flora containing many rare species suggests that they are a reservoir for biodiversity not just for vascular plants, but also for lichens. Kluwer Academic Publishers, 2000 Cliff vegetation nationallicence Canonical correspondence analysis nationallicence Detrended correspondence analysis nationallicence Rock faces nationallicence Saxicolous lichens nationallicence Spatial scales nationallicence Matthes Uta Cliff Ecology Research Group, Department of Botany, University of Guelph, N1G 2W1, Guelph, Ontario, Canada aut Ryan Bruce Department of Plant Biology, Arizona State University, Box 871601, 85287-1601, Tempe, AZ, USA aut Larson Douglas Cliff Ecology Research Group, Department of Botany, University of Guelph, N1G 2W1, Guelph, Ontario, Canada aut Plant Ecology Kluwer Academic Publishers 148/2(2000-06-01), 233-244 1385-0237 148:2<233 2000 148 11258 https://doi.org/10.1023/A:1009832507791 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1009832507791 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Matthes Uta Cliff Ecology Research Group, Department of Botany, University of Guelph, N1G 2W1, Guelph, Ontario, Canada aut NATIONALLICENCE 700 1- Ryan Bruce Department of Plant Biology, Arizona State University, Box 871601, 85287-1601, Tempe, AZ, USA aut NATIONALLICENCE 700 1- Larson Douglas Cliff Ecology Research Group, Department of Botany, University of Guelph, N1G 2W1, Guelph, Ontario, Canada aut NATIONALLICENCE 773 0- Plant Ecology Kluwer Academic Publishers 148/2(2000-06-01), 233-244 1385-0237 148:2<233 2000 148 11258 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer