Ecology of the corticolous lichens on Pinus radiata at five sites of increasing age near Linton, Victoria, Australia

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Abstract

Abstract Thirteen lichen species were studied on trunk segments of Pinus radiata D.Don between 1.0 and 1.5m above-ground from five plantings of known, different ages near Linton, Victoria. Significant frequency and size-class differences were found for most species between sites. These parameters generally increased up to 32 years, and then either declined or showed evidence of recolonization by small thallus size-classes in some species. Nevertheless, only relict populations for any species were present at 52 years. Most species had no aspect preferences; only three species had a significant majority of their thalli on the western trunk face. Site-species association frequency analyses clustered, as pairs, the 11 and 52, and 16 and 39 year old sites. These site patterns were correlated with a number of environmental factors as well as species abundance at the sites, but there is also a possible response by the community to bark shedding, seen after 32 years, with a return to earlier colonization states in the system. This cyclic pattern is similar to a competitive hierarchy succession, although due to accelerating chronic disturbance (bark shedding) the system may be subject to secondary succession and, ultimately, to severe degradation.

Ancillary